Patent Application
20250063941
The present disclosure generally relates to OLED devices and their uses in related electronic devices including consumer products.
Opto-electronic devices that make use of organic materials are becoming increasingly desirable for various reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting diodes/devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials.
OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting.
One application for phosphorescent emissive molecules is a full color display. Industry standards for such a display call for pixels adapted to emit particular colors, referred to as “saturated” colors. In particular, these standards call for saturated red, green, and blue pixels. Alternatively, the OLED can be designed to emit white light. In conventional liquid crystal displays emission from a white backlight is filtered using absorption filters to produce red, green and blue emission. The same technique can also be used with OLEDs. The white OLED can be either a single emissive layer (EML) device or a stack structure. Color may be measured using CIE coordinates, which are well known to the art.
In one aspect, the present disclosure provides an organic light emitting device (OLED) comprising a light emitting stack that comprises: a first electrode; a second electrode; a first layer disposed between the first electrode and the second electrode; wherein the first layer is selected from the group consisting of hole injecting layer (HIL), hole transporting layer (HTL), electron blocking layer (EBL), emissive layer (EML), hole blocking layer (HBL), electron transporting layer (ETL), and electron injecting layer (EIL); wherein the first layer comprises a first compound and a second compound mixed together; wherein the first compound comprises a first element (F1) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; wherein the second compound comprises a first element (S1) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; and wherein the first element (F1) of the first compound can be same or different from the first element (S1) of the second compound.
In another aspect, the present disclosure provides a consumer product comprising an OLED as described in the present disclosure.
Unless otherwise specified, the below terms used herein are defined as follows:
As used herein, “top” means furthest away from the substrate, while “bottom” means closest to the substrate. Where a first layer is described as “disposed over” a second layer, the first layer is disposed further away from substrate. There may be other layers between the first and second layer, unless it is specified that the first layer is “in contact with” the second layer. For example, a cathode may be described as “disposed over” an anode, even though there are various organic layers in between.
As used herein, “solution processable” means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.
As used herein, and as would be generally understood by one skilled in the art, a first “Highest Occupied Molecular Orbital” (HOMO) or “Lowest Unoccupied Molecular Orbital” (LUMO) energy level is “greater than” or “higher than” a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Since ionization potentials (IP) are measured as a negative energy relative to a vacuum level, a higher HOMO energy level corresponds to an IP having a smaller absolute value (an IP that is less negative). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) having a smaller absolute value (an EA that is less negative). On a conventional energy level diagram, with the vacuum level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A “higher” HOMO or LUMO energy level appears closer to the top of such a diagram than a “lower” HOMO or LUMO energy level.
As used herein, and as would be generally understood by one skilled in the art, a first work function is “greater than” or “higher than” a second work function if the first work function has a higher absolute value. Because work functions are generally measured as negative numbers relative to vacuum level, this means that a “higher” work function is more negative. On a conventional energy level diagram, with the vacuum level at the top, a “higher” work function is illustrated as further away from the vacuum level in the downward direction. Thus, the definitions of HOMO and LUMO energy levels follow a different convention than work functions.
The terms “halo,” “halogen,” and “halide” are used interchangeably and refer to fluorine, chlorine, bromine, and iodine.
The term “acyl” refers to a substituted carbonyl group (—C(O)—Rs).
The term “ester” refers to a substituted oxycarbonyl (—O—C(O)—Rs or —C(O)—O—Rs) group.
The term “ether” refers to an —OR, group.
The terms “sulfanyl” or “thio-ether” are used interchangeably and refer to a —SR, group.
The term “selenyl” refers to a —SeRs group.
The term “sulfinyl” refers to a —S(O)—Rs group.
The term “sulfonyl” refers to a —SO2—Rs group.
The term “phosphino” refers to a group containing at least one phosphorus atom used to be bonded to the relevant molecule, common examples such as, but not limited to, a —P(Rs)2 group or a —PO(Rs)2 group, wherein each Rs can be same or different.
The term “silyl” refers to a group containing at least one silicon atom used to be bonded to the relevant molecule, common examples such as, but not limited to, a —Si(Rs)3 group, wherein each Rs can be same or different.
The term “germyl” refers to a group containing at least one germanium atom used to be bonded to the relevant molecule, common examples such as, but not limited to, a —Ge(Rs)3 group, wherein each Rs can be same or different.
The term “boryl” refers to a group containing at least one boron atom used to be bonded to the relevant molecule, common examples such as, but not limited to, a —B(Rs)2 group or its Lewis adduct —B(Rs)3 group, wherein Rs can be same or different.
In each of the above, Rs can be hydrogen or the general substituents as defined in this application. Preferred Rs is selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, and combination thereof. More preferably Rs is selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl, and combination thereof.
The term “alkyl” refers to and includes both straight and branched chain alkyl groups. Preferred alkyl groups are those containing from one to fifteen carbon atoms, preferably one to nine carbon atoms, and includes methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, and the like. Additionally, the alkyl group can be further substituted.
The term “cycloalkyl” refers to and includes monocyclic, polycyclic, and spiro alkyl groups. Preferred cycloalkyl groups are those containing 3 to 12 ring carbon atoms and includes cyclopropyl, cyclopentyl, cyclohexyl, bicyclo[3.1.1]heptyl, spiro[4.5]decyl, spiro[5.5]undecyl, adamantyl, and the like. Additionally, the cycloalkyl group can be further substituted.
The terms “heteroalkyl” or “heterocycloalkyl” refer to an alkyl or a cycloalkyl group, respectively, having at least one carbon atom replaced by a heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, Ge and Se, preferably, O, S or N. Additionally, the heteroalkyl or heterocycloalkyl group can be further substituted.
The term “alkenyl” refers to and includes both straight and branched chain alkene groups. Alkenyl groups are essentially alkyl groups that include at least one carbon-carbon double bond in the alkyl chain. Cycloalkenyl groups are essentially cycloalkyl groups that include at least one carbon-carbon double bond in the cycloalkyl ring. The term “heteroalkenyl” as used herein refers to an alkenyl group having at least one carbon atom replaced by a heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, Ge, and Se, preferably, O, S, or N. Preferred alkenyl, cycloalkenyl, or heteroalkenyl groups are those containing two to fifteen carbon atoms. Additionally, the alkenyl, cycloalkenyl, or heteroalkenyl group can be further substituted.
The term “alkynyl” refers to and includes both straight and branched chain alkyne groups. Alkynyl groups are essentially alkyl groups that include at least one carbon-carbon triple bond in the alkyl chain. Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group can be further substituted.
The terms “aralkyl” or “arylalkyl” are used interchangeably and refer to an alkyl group that is substituted with an aryl group. Additionally, the aralkyl group can be further substituted.
The term “heterocyclic group” refers to and includes aromatic and non-aromatic cyclic groups containing at least one heteroatom. Optionally the at least one heteroatom is selected from O, S, Se, N, P, B, Si, Ge, and Se, preferably, O, S, N, or B. Hetero-aromatic cyclic groups may be used interchangeably with heteroaryl. Preferred hetero-non-aromatic cyclic groups are those containing 3 to 10 ring atoms, preferably those containing 3 to 7 ring atoms, which includes at least one hetero atom, and includes cyclic amines such as morpholino, piperidino, pyrrolidino, and the like, and cyclic ethers/thio-ethers, such as tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, and the like. Additionally, the heterocyclic group can be further substituted or fused.
The term “aryl” refers to and includes both single-ring and polycyclic aromatic hydrocarbyl groups. The polycyclic rings may have two or more rings in which two carbons are common to two adjoining rings (the rings are “fused”). Preferred aryl groups are those containing six to thirty carbon atoms, preferably six to twenty-four carbon atoms, six to eighteen carbon atoms, and more preferably six to twelve carbon atoms. Especially preferred is an aryl group having six carbons, ten carbons, twelve carbons, fourteen carbons, or eighteen carbons. Suitable aryl groups include phenyl, biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, pyrene, chrysene, perylene, and azulene, preferably phenyl, biphenyl, triphenyl, triphenylene, and naphthalene. Additionally, the aryl group can be further substituted or fused such as, but not limited to, fluorene.
The term “heteroaryl” refers to and includes both single-ring aromatic groups and polycyclic aromatic ring systems that include at least one heteroatom. The heteroatoms include, but are not limited to O, S, Se, N, P, B, Si, Ge, and Se. In many instances, O, S, N, or B are the preferred heteroatoms. Hetero-single ring aromatic systems are preferably single rings with 5 or 6 ring atoms, and the ring can have from one to six heteroatoms. The hetero-polycyclic ring systems can have two or more aromatic rings in which two atoms are common to two adjoining rings (the rings are “fused”) wherein at least one of the rings is a heteroaryl. The hetero-polycyclic aromatic ring systems can have from one to six heteroatoms per ring of the polycyclic aromatic ring system. Preferred heteroaryl groups are those containing three to thirty carbon atoms, preferably three to twenty-four carbon atoms, three to eighteen carbon atoms, and more preferably three to twelve carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine, preferably dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, triazine, benzimidazole, 1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazine, and aza-analogs thereof. Additionally, the heteroaryl group can be further substituted or fused.
Of the aryl and heteroaryl groups listed above, the groups of triphenylene, naphthalene, anthracene, dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, pyrazine, pyrimidine, triazine, and benzimidazole, and the respective aza-analogs of each thereof are of particular interest.
In many instances, the general substituents are selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, selenyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
In some instances, the preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, germyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.
In some instances, the more preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silyl, aryl, heteroaryl, nitrile, sulfanyl, and combinations thereof.
In some instances, the more preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, silyl, aryl, heteroaryl, nitrile, and combinations thereof.
In yet other instances, the most preferred general substituents are selected from the group consisting of deuterium, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof.
The terms “substituted” and “substitution” refer to a substituent other than H that is bonded to the relevant position, e.g., a carbon or nitrogen. For example, when R1 represents mono-substitution, then one R1 must be other than H (i.e., a substitution). Similarly, when R1 represents di-substitution, then two of R1 must be other than H. Similarly, when R1 represents zero or no substitution, R1, for example, can be a hydrogen for available valencies of ring atoms, as in carbon atoms for benzene and the nitrogen atom in pyrrole, or simply represents nothing for ring atoms with fully filled valencies, e.g., the nitrogen atom in pyridine. The maximum number of substitutions possible in a ring structure will depend on the total number of available valencies in the ring atoms.
As used herein, “combinations thereof” indicates that one or more members of the applicable list are combined to form a known or chemically stable arrangement that one of ordinary skill in the art can envision from the applicable list. For example, an alkyl and deuterium can be combined to form a partial or fully deuterated alkyl group; a halogen and alkyl can be combined to form a halogenated alkyl substituent; and a halogen, alkyl, and aryl can be combined to form a halogenated arylalkyl. In one instance, the term substitution includes a combination of two to four of the listed groups. In another instance, the term substitution includes a combination of two to three groups. In yet another instance, the term substitution includes a combination of two groups. Preferred combinations of substituent groups are those that contain up to fifty atoms that are not hydrogen or deuterium, or those which include up to forty atoms that are not hydrogen or deuterium, or those that include up to thirty atoms that are not hydrogen or deuterium. In many instances, a preferred combination of substituent groups will include up to twenty atoms that are not hydrogen or deuterium.
The “aza” designation in the fragments described herein, i.e. aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more of the C—H groups in the respective aromatic ring can be replaced by a nitrogen atom, for example, but not limited to, azatriphenylene encompasses both dibenzo[f;h]quinoxaline and dibenzo[f;h]quinoline. One of ordinary skill in the art can readily envision other nitrogen analogs of the aza-derivatives described above, and all such analogs are intended to be encompassed by the terms as set forth herein.
As used herein, “deuterium” refers to an isotope of hydrogen. Deuterated compounds can be readily prepared using methods known in the art. For example, U.S. Pat. No. 8,557,400, Patent Pub. No. WO 2006/095951, and U.S. Pat. Application Pub. No. US 2011/0037057, which are hereby incorporated by reference in their entireties, describe the making of deuterium-substituted organometallic complexes. Further reference is made to Ming Yan, et al., Tetrahedron 2015, 71, 1425-30 and Atzrodt et al., Angew. Chem. Int. Ed. (Reviews) 2007, 46, 7744-65, which are incorporated by reference in their entireties, describe the deuteration of the methylene hydrogens in benzyl amines and efficient pathways to replace aromatic ring hydrogens with deuterium, respectively.
As used herein, any specifically listed substituent such as, but not limited to, methyl, phenyl, pyridyl, etc. includes undeuterated, partially deuterated, and fully deuterated versions thereof. Similarly, classes of substituents such as, but not limited to, alkyl, aryl, cycloalkyl, heteroaryl, etc. also include undeuterated, partially deuterated, and fully deuterated versions thereof. A chemical structure without further specified H or D should be considered to include undeuterated, partially deuterated, and fully deuterated versions thereof. Some common smallest partially or fully deuterated group such as, but not limited to, CD3, CD2C(CH3)3, C(CD3)3, and C6D5.
It is to be understood that when a molecular fragment is described as being a substituent or otherwise attached to another moiety, its name may be written as if it were a fragment (e.g. phenyl, phenylene, naphthyl, dibenzofuryl) or as if it were the whole molecule (e.g. benzene, naphthalene, dibenzofuran). As used herein, these different ways of designating a substituent or attached fragment are considered to be equivalent.
In some instances, a pair of substituents in the molecule can be optionally joined or fused into a ring. The preferred ring is a five to nine-membered carbocyclic or heterocyclic ring, includes both instances where the portion of the ring formed by the pair of substituents is saturated and where the portion of the ring formed by the pair of substituents is unsaturated. In yet other instances, a pair of adjacent substituents can be optionally joined or fused into a ring. As used herein, “adjacent” means that the two substituents involved can be on the same ring next to each other, or on two neighboring rings having the two closest available substitutable positions, such as 2, 2′ positions in a biphenyl, or 1, 8 position in a naphthalene.
Layers, materials, regions, and devices may be described herein in reference to the color of light they emit. In general, as used herein, an emissive region that is described as producing a specific color of light may include one or more emissive layers disposed over each other in a stack.
As used herein, a “red” layer, material, region, or device refers to one that emits light in the range of about 580-700 nm or having a highest peak in its emission spectrum in that region. Similarly, a “green” layer, material, region, or device refers to one that emits or has an emission spectrum with a peak wavelength in the range of about 500-600 nm; a “blue” layer, material, or device refers to one that emits or has an emission spectrum with a peak wavelength in the range of about 400-500 nm; and a “yellow” layer, material, region, or device refers to one that has an emission spectrum with a peak wavelength in the range of about 540-600 nm. In some arrangements, separate regions, layers, materials, regions, or devices may provide separate “deep blue” and a “light blue” light. As used herein, in arrangements that provide separate “light blue” and “deep blue”, the “deep blue” component refers to one having a peak emission wavelength that is at least about 4 nm less than the peak emission wavelength of the “light blue” component. Typically, a “light blue” component has a peak emission wavelength in the range of about 465-500 nm, and a “deep blue” component has a peak emission wavelength in the range of about 400-470 nm, though these ranges may vary for some configurations. Similarly, a color altering layer refers to a layer that converts or modifies another color of light to light having a wavelength as specified for that color. For example, a “red” color filter refers to a filter that results in light having a wavelength in the range of about 580-700 nm. In general, there are two classes of color altering layers: color filters that modify a spectrum by removing unwanted wavelengths of light, and color changing layers that convert photons of higher energy to lower energy. A component “of a color” refers to a component that, when activated or used, produces or otherwise emits light having a particular color as previously described. For example, a “first emissive region of a first color” and a “second emissive region of a second color different than the first color” describes two emissive regions that, when activated within a device, emit two different colors as previously described.
As used herein, emissive materials, layers, and regions may be distinguished from one another and from other structures based upon light initially generated by the material, layer or region, as opposed to light eventually emitted by the same or a different structure. The initial light generation typically is the result of an energy level change resulting in emission of a photon. For example, an organic emissive material may initially generate blue light, which may be converted by a color filter, quantum dot or other structure to red or green light, such that a complete emissive stack or sub-pixel emits the red or green light. In this case the initial emissive material or layer may be referred to as a “blue” component, even though the sub-pixel is a “red” or “green” component.
In some cases, it may be preferable to describe the color of a component such as an emissive region, sub-pixel, color altering layer, or the like, in terms of 1931 CIE coordinates. For example, a yellow emissive material may have multiple peak emission wavelengths, one in or near an edge of the “green” region, and one within or near an edge of the “red” region as previously described. Accordingly, as used herein, each color term also corresponds to a shape in the 1931 CIE coordinate color space. The shape in 1931 CIE color space is constructed by following the locus between two color points and any additional interior points. For example, interior shape parameters for red, green, blue, and yellow may be defined as shown below:
More details on OLEDs, and the definitions described above, can be found in U.S. Pat. No. 7,279,704, which is incorporated herein by reference in its entirety.
As disclosed herein, emissive layers or materials, such as emissive layer 135 and emissive layer 220 shown in
Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties, organic vapor phase deposition (OVPD), such as described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety, and deposition by organic vapor jet printing (OVJP, also referred to as organic vapor jet deposition (OVJD)), such as described in U.S. Pat. No. 7,431,968, which is incorporated by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, and patterning associated with some of the deposition methods such as ink-jet and OVJD. Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having 20 carbons or more may be used, and 3-20 carbons is a preferred range. Materials with asymmetric structures may have better solution processibility than those having symmetric structures, because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.
Devices fabricated in accordance with embodiments of the present disclosure may further optionally comprise a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment including moisture, vapor and/or gases, etc. The barrier layer may be deposited over, under or next to a substrate, an electrode, or over any other parts of a device including an edge. The barrier layer may comprise a single layer, or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include compositions having a single phase as well as compositions having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate an inorganic or an organic compound or both. The preferred barrier layer comprises a mixture of a polymeric material and a non-polymeric material as described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos. PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporated by reference in their entireties. To be considered a “mixture”, the aforesaid polymeric and non-polymeric materials comprising the barrier layer should be deposited under the same reaction conditions and/or at the same time. The weight ratio of polymeric to non-polymeric material may be in the range of 95:5 to 5:95. The polymeric material and the non-polymeric material may be created from the same precursor material. In one example, the mixture of a polymeric material and a non-polymeric material consists essentially of polymeric silicon and inorganic silicon.
It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistics limit through delayed fluorescence. As used herein, there are two types of delayed fluorescence, i.e. P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence is generated from triplet-triplet annihilation (TTA).
On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the thermal population between the triplet states and the singlet excited states. Compounds that are capable of generating E-type delayed fluorescence are required to have very small singlet-triplet gaps. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A distinctive feature of TADF is that the delayed component increases as temperature rises due to the increased thermal energy. If the reverse intersystem crossing rate is fast enough to minimize the non-radiative decay from the triplet state, the fraction of back populated singlet excited states can potentially reach 75%. The total singlet fraction can be 100%, far exceeding the spin statistics limit for electrically generated excitons.
E-type delayed fluorescence characteristics can be found in an exciplex system or in a single compound. Without being bound by theory, it is believed that E-type delayed fluorescence requires the luminescent material to have a small singlet-triplet energy gap (AES-T). Organic, non-metal containing, donor-acceptor luminescent materials may be able to achieve this. The emission in these materials is often characterized as a donor-acceptor charge-transfer (CT) type emission. The spatial separation of the HOMO and LUMO in these donor-acceptor type compounds often results in small AES-T. These states may involve CT states. Often, donor-acceptor luminescent materials are constructed by connecting an electron donor moiety such as amino- or carbazole-derivatives and an electron acceptor moiety such as N-containing six-membered aromatic ring.
Devices fabricated in accordance with embodiments of the disclosure can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into a variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include display screens, lighting devices such as discrete light source devices or lighting panels, etc. that can be utilized by the end-user product manufacturers. Such electronic component modules can optionally include the driving electronics and/or power source(s). Devices fabricated in accordance with embodiments of the disclosure can be incorporated into a wide variety of consumer products that have one or more of the electronic component modules (or units) incorporated therein. A consumer product comprising an OLED that includes the compound of the present disclosure in the organic layer in the OLED is disclosed. Such consumer products would include any kind of products that include one or more light source(s) and/or one or more of some type of visual displays. Some examples of such consumer products include a flat panel display, a curved display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a cell phone, tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video walls comprising multiple displays tiled together, a theater or stadium screen, and a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present disclosure, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as 18 C to 30 C, and more preferably at room temperature (20-25 C), but could be used outside this temperature range, for example, from −40 C to 80 C.
The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may employ the materials and structures. More generally, organic devices, such as organic transistors, may employ the materials and structures.
In general parlance in the art, a “sub-pixel” may refer to the emissive region, which may be a single-layer EML, a stacked device, or the like, in conjunction with any color altering layer that is used to modify the color emitted by the emissive region.
As used herein, the “emissive region” of a sub-pixel refers to any and all emissive layers, regions, and devices that are used initially to generate light for the sub-pixel. A sub-pixel also may include additional layers disposed in a stack with the emissive region that affect the color ultimately produced by the sub-pixel, such as color altering layers disclosed herein, though such color altering layers typically are not considered “emissive layers” as disclosed herein. An unfiltered sub-pixel is one that excludes a color modifying component such as a color altering layer, but may include one or more emissive regions, layers, or devices.
In some configurations, an “emissive region” may include emissive materials that emit light of multiple colors. For example, a yellow emissive region may include multiple materials that emit red and green light when each material is used in an OLED device alone. When used in a yellow device, the individual materials typically are not arranged such that they can be individually activated or addressed. That is, the “yellow” OLED stack containing the materials cannot be driven to produce red, green, or yellow light; rather, the stack can be driven as a whole to produce yellow light. Such an emissive region may be referred to as a yellow emissive region even though, at the level of individual emitters, the stack does not directly produce yellow light. As described in further detail below, the individual emissive materials used in an emissive region (if more than one), may be placed in the same emissive layer within the device, or in multiple emissive layers within an OLED device comprising an emissive region. As described in further detail below, embodiments disclosed herein may allow for OLED devices such as displays that include a limited number of colors of emissive regions, while including more colors of sub-pixels or other OLED devices than the number of colors of emissive regions. For example, a device as disclosed herein may include only blue and yellow emissive regions. Additional colors of sub-pixels may be achieved by the use of color altering layers, such as color altering layers disposed in a stack with yellow or blue emissive regions, or more generally through the use of color altering layers, electrodes or other structures that form a microcavity as disclosed herein, or any other suitable configuration. In some cases, the general color provided by a sub-pixel may be the same as the color provided by the emissive region in the stack that defines the sub-pixel, such as where a deep blue color altering layer is disposed in a stack with a light blue emissive region to produce a deep blue sub-pixel. Similarly, the color provided by a sub-pixel may be different than the color provided by an emissive region in the stack that defines the sub-pixel, such as where a green color altering layer is disposed in a stack with a yellow emissive region to product a green sub-pixel.
In some configurations, emissive regions and/or emissive layers may span multiple sub-pixels, such as where additional layers and circuitry are fabricated to allow portions of an emissive region or layer to be separately addressable.
An emissive region as disclosed herein may be distinguished from an emissive “layer” as typically referred to in the art and as used herein. In some cases, a single emissive region may include multiple layers, such as where a yellow emissive region is fabricated by sequentially red and green emissive layers to form the yellow emissive region. As previously described, when such layers occur in an emissive region as disclosed herein, the layers are not individually addressable within a single emissive stack; rather, the layers are activated or driven concurrently to produce the desired color of light for the emissive region. In other configurations, an emissive region may include a single emissive layer of a single color, or multiple emissive layers of the same color, in which case the color of such an emissive layer will be the same as, or in the same region of the spectrum as, the color of the emissive region in which the emissive layer is disposed.
In one aspect, the present disclosure provides an organic light emitting device (OLED) comprising a light emitting stack that comprises: a first electrode; a second electrode; a first layer disposed between the first electrode and the second electrode; wherein the first layer is selected from the group consisting of hole injecting layer (HIL), hole transporting layer (HTL), electron blocking layer (EBL), emissive layer (EML), hole blocking layer (HBL), electron transporting layer (ETL), and electron injecting layer (EIL); wherein the first layer comprises a first compound and a second compound mixed together; wherein the first compound comprises a first element (F1) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; wherein the second compound comprises a first element (S1) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; and wherein the first element (F1) of the first compound can be same or different from the first element (S1) of the second compound.
It should be understood that the positional order of the group of layers EBL, HTL, and HIL and the group of layers HBL, ETL, and EIL in the OLED with respect to the EML and the anode and cathode electrodes is as shown in
In some embodiments, the OLED is a single-stack device having one light emitting stack defined herein. In some embodiments, the OLED can be a stacked device, which refers to an OLED in which two or more light emitting stacks are stacked in series. In a stacked device the electrode that is situated between two adjacent light emitting stacks is referred to as a CGL.
In the present disclosure, each component in the multi-component layers is referring to a chemical compound and it is intended to mean that the multiple chemical compounds in the layer are mixed together in that layer. In such multi-component layer, each of the chemical compounds can have a uniform concentration throughout the bulk of the layer or can be present with a concentration gradient profile through the thickness of the layer. In other words, if x-y-z coordinate system is applied to a layer with the x-y plane representing the plane of the layer, the concentration gradient profile of a chemical compound defines the variation in the concentration of that chemical compound along the z axis of the layer. Each chemical compound in a given layer independently has its own concentration gradient profile. In some embodiments, the concentration gradient profile of each of the two or more chemical compounds in a given layer can be the same or different.
As a general matter, some of the functional layers (e.g. HIL, HTL, EBL, HBL, EIL, ETL, regardless of whether they are multi-component type or not) may be absent in a given OLED device. However, the functional layer pairs HTL/HIL and/or ETL/EIL are considered as essential layers when their respective EBL and/or HBL are present in the OLED. In other words, EBL and HBL each can only be present where there are at least three different layers present between the respective electrode and the EML, where the three layers include EBL or HBL depending on which electrode side of the OLED. For example, If an OLED has an EBL adjacent the EML between the EML and the anode, there must be an HTL and an HIL between the EBL and the anode. If an OLED has an HBL adjacent the EML between the EML and the cathode, there must be an ETL and an EIL between the HBL and the cathode. The functional layer pairs HTL/HIL and/or ETL/EIL, however, can be present in an OLED without EBL or HBL present.
In some embodiments, the first compound further comprises a second element (F2) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; and wherein its first element (F1) is different from its second element (F2).
In some embodiments, the second compound further comprises a second element (S2) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; and wherein its first element (S1) is different from its second element (S2).
In some embodiments, the first compound further comprises a third element (F3) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; and wherein its first, its second and its third elements are different from each other.
In some embodiments, the second compound further comprises a third element (S3) selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se; and wherein its first, its second, and its third elements are different from each other.
In some embodiments, a substituent comprising F1 is defined as FS1, a substituent comprising F2 is defined as FS2, a substituent comprising F3 is defined as FS3, a substituent comprising S1 is defined as SS1, a substituent comprising S2 is defined as SS2, a substituent comprising S3 is defined as SS3.
In some embodiments, both the first element (F1) and the second element (F2) of the first compound are attached to the same ring. In some embodiments, any two of the first element (F1), the second element (F2), and the third element (F3) of the first compound are attached to the same ring. In some embodiments, the first element (F1), the second element (F2), and the third element (F3) of the first compound are all attached to the same ring.
In some embodiments, both FS1 and FS2 of the first compound are attached to the same ring. In some embodiments, any two of the FS1, FS2, and FS3 of the first compound are attached to the same ring. In some embodiments, each of the FS1, FS2, and FS3 of the first compound are all attached to the same ring.
In some embodiments, the first element (F1) and the second element (F2) of the first compound are attached to different rings. In some embodiments, each of the first element (F1), the second element (F2), and the third element (F3) of the first compound is attached to a different ring.
In some embodiments, the FS1 and FS2 of the first compound are attached to different rings. In some embodiments, each of the FS1, FS2, and FS3 of the first compound is attached to a different ring.
In some embodiments, both the first element (S1) and the second element (S2) of the second compound are attached to the same ring. In some embodiments, any two of the first element (S1), the second element (S2), and the third element (S3) of the second compound are attached to the same ring. In some embodiments, the first element (S1), the second element (S2), and the third element (S3) of the second compound are all attached to the same ring.
In some embodiments, both the SS1 and SS2 of the second compound are attached to the same ring. In some embodiments, any two of the SS1, SS2, and SS3 of the second compound are attached to the same ring. In some embodiments, each of the SS1, SS2, and SS3 of the second compound are all attached to the same ring.
In some embodiments, the first element (S1) and the second element (S2) of the second compound are attached to different rings. In some embodiments, each of the first element (S1), the second element (S2), and the third element (S3) of the second compound is attached to a different ring.
In some embodiments, the SS1 and SS2 of the second compound are attached to different rings. In some embodiments, each of the SS1, SS2, and SS3 of the second compound is attached to a different ring.
In some embodiments, the first compound and/or the second compound can comprise a Si substituted and deuterated aryl with a CN group. In some embodiments, the first compound and/or the second compound can comprise a Si substituted and deuterated aryl without a CN group.
In some embodiments, the first compound and/or the second compound can comprise a silyl substituted fluoroalkyl group.
In some embodiments, the first layer further comprises a third compound mixed with the first and the second compounds; wherein the third compound comprises at least one element selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se. In some of the above embodiments, the third compound comprises at least two different elements selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se. In some of the above embodiments, the third compound comprises at least three different elements selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se.
In some embodiments, the OLED further comprises a second layer disposed between the first electrode and the second electrode; wherein the second layer is selected from the group consisting of HIL, HTL, EBL, EML, HBL, ETL, and EIL; the second layer is a different type of layer from the first layer; and the second layer comprises a third compound; wherein the third compound comprises at least one element selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se. In some of the above embodiments, the third compound comprises at least two different elements selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se. In some of the above embodiments, the third compound comprises at least three different elements selected from the group consisting of D, F, CN, Si, Ge, P, B, and Se.
In some embodiments, the first layer is EML.
In some embodiments, the first layer is EBL or HBL.
In some embodiments, the first layer is HIL or HTL.
In some embodiments, the first layer is ETL or EIL.
In some embodiments, the first layer is EML; wherein the first compound is a first emitter, the second compound is a first host. In some such embodiments, the first element is D, and the first compound comprises both a fully or partially deuterated alkyl group and a fully or partially deuterated aryl group. In some of these embodiments, the first element (S1) of the second compound is B. In some such embodiments, the second element (S2) of the second compound is D. In some such embodiments, the first element S1 of the second compound is CN. In some such embodiments, the first element S1 of the second compound is Ge. In some such embodiments, the first element S1 and the second element (S2) of the second compound are Si and D.
In some embodiments, both the second and third compounds comprise Si. In some embodiments, both the second and third compounds comprise both Si and D.
In some of these embodiments, the first element (F1) of the first compound is selected from the group consisting of D, CN, and Si. In some of these embodiments, the second element (F2) of the first compound is selected from the group consisting of D, CN, and Si.
In some embodiments, both F1 and S1 are Si. In some embodiments, both F1 and S1 are CN. In some embodiments, both F1 and S1 are B. In some embodiments, F1 is Si and S1 is B. In some embodiments, F1 is Si and S1 is CN. In some embodiments, F1 is CN and S1 is B. In some embodiments, one of F2 and S2 is D. In some embodiments, both F2 and S2 are D. In some embodiments, the third compound comprises D, B, CN, or Si.
In some embodiments, the first layer is EML; wherein the first compound is a first emitter, the second compound is a second emitter.
In some embodiments, the first layer is EML; wherein the first compound is a first host, the second compound is a second host. In some of these embodiments, the first element (S1) of the second compound is B. In some of these embodiments, the first element (F1) of the first compound is selected from the group consisting of D, CN, Si, Se, and Ge. In some of these embodiments, the second element (F2) of the first compound is selected from the group consisting of D, CN, Si, Se, and Ge. In some of the above embodiments, the first compound comprises a group SiAr1 Ar2 Ar3 wherein Ar1, Ar2, and Ar3 are each independently a substituted or unsubstituted aryl or heteroaryl ring; Ar1, Ar2, and Ar3 can optionally be fused or joined to form a ring.
In some of the above embodiments, both F1 and S1 are Si and F2 is D. In some of the above embodiments, both F1 and S1 are CN. In some of the above embodiments, both F1 and S1 are B. In some of the above embodiments, F1 is Si and S1 is CN. In some of the above embodiments, F1 is Si, F2 is CN, and S1 is selected from the group consisting of Si, B, and CN. In some of the above embodiments, F1 is Si and S1 is B. F1 is B and S1 is CN. In some of the above embodiments, at least one of the first and second compounds comprises D. In some of the above embodiments, both of the first and second compounds comprise D. In some of the above embodiments, the third compound comprises D, B, CN, or Si.
In some of the above embodiments, the first compound has a structure selected from the group consisting of:
In some embodiments, the organic linker is selected from the group consisting of a direct bond, BR, BRR′, NR, PR, P(O)R, O, S, Se, C═O, C═S, C═Se, C═NR′, C═CR′R″, S═O, SO2, CR, CRR′, SiRR′, GeRR′, alkylene, cycloalkyl, aryl, cycloalkylene, arylene, heteroarylene, and combinations thereof.
In some of the above embodiments, at least one of RA′, RB′, RC′, RD′, RE′, RF′, and RG′ is selected from the group consisting of deuterium, fluorine, nitrile, partially or fully deuterated alkyl, partially or fully deuterated heteroalkyl, partially or fully deuterated aryl, partially or fully deuterated heteroaryl, partially or fully fluorinated alkyl, partially or fully fluorinate heteroalkyl, partially or fully fluorinate aryl, partially or fully fluorinate heteroaryl, alkyl silyl, heteroalkyl silyl, aryl silyl, heteroaryl silyl, alkyl germyl, heteroalkyl germyl, aryl germyl, heteroaryl germyl, boryl alkyl, boryl heteroalkyl, boryl aryl, boryl heteroaryl, boryl fluoro, borate, borole, azaborole, diazaborole, oxazaborole, azaborinine, oxaborinine, cyano substituted aryl, cyano substituted hetero aryl, cyano substituted alkyl, cyano substituted heteroalkyl, aryl selenyl, alkyl selenyl, heteroaryl selenyl, heteroalkyl selenyl, benzoselenophene, dibenzoselenophene, aryl phosphine, alkyl phosphine, heteroaryl phosphine, heteroalkyl phosphine, phosphine oxide, which may be further substituted.
In some embodiments, the first compound can be selected from the group consisting of
In some embodiments, at least one of the first, second, and third compound comprises a group selected from:
and aza variants thereof, fully or partially deuterated variants thereof, and combinations thereof;
In some embodiments, the second compound has a structure selected from the group consisting of
aza variants thereof, fully or partially deuterated variants thereof,
In some of the above embodiments, the first compound has a structure selected from the group consisting of:
In some embodiments, the first layer is EML; wherein the first compound is a first emitter, the second compound is a first host, the third compound is a second host. In some of these embodiments, the first element (S1) of the second compound is B. In some of these embodiments, the first element (F1) of the first compound is selected from the group consisting of D, CN, Si, Se, and Ge and the third compound comprises an element selected from the group consisting of D, CN, Si, Se, and Ge. In some of these embodiments, the first element (F1) of the first compound is selected from the group consisting of D, CN, F, and Si, and the third compound comprises an element selected from the group consisting of D, Si, and Ge.
In some of the above embodiments, the second element (S2) of the second compound is selected from the group consisting of D, CN, Si, Se, and Ge.
In some embodiments, the second compound has a structure of Formula I,
In some of the above embodiments, the second compound has a structure selected from the group consisting of
In some embodiments, the second compound has a structure selected from the group consisting of
In some of the above embodiments, at least one of RA, RB, RC, RA′, RB′, RC′, RD′, RE′, and RF′ comprises D.
In some of the above embodiments, the second compound comprises Si.
In some of the above embodiments, the second compound has a structure selected from the group consisting of
In some of the above embodiments, the first host is a hole transporting host, the second host is an electron transporting host. In some of the above embodiments, the first host and the second host form an exciplex.
In some embodiments, the first layer is EML; wherein the first compound is a first acceptor, the second compound is a first sensitizer, the third compound is a first host. In some embodiments, the first acceptor is a delayed fluorescent capable material or fluorescent material. In some embodiments, the first sensitizer is a phosphorescent or delayed fluorescent capable material.
In some embodiments, the first layer is EML; wherein the first compound is a first emitter, the second compound is a second emitter, the third compound is a first host.
In some embodiments, each component in a layer in direct contact with the EML has a higher T1 energy than any component in the EML by at least 0.1 eV.
In some embodiments, the first layer is EBL or HBL; and each component in the first layer has a HOMO energy within about 0.4 eV of each other, and/or a LUMO energy within 0.4 eV of each other.
In some embodiments, the first layer is EBL or HBL; and wherein the first compound is a hole transporting compound, and the second compound is an electron transporting compound.
In some embodiments, the first element (F1) of the first compound is attached to an unsaturated carbon atom. In some embodiments, the first element (F1) of the first compound is attached to a saturated carbon atom. In some embodiments, the first element (F1) of the first compound is attached to a Si or Ge atom. In some embodiments, the first element (F1) of the first compound is attached to a first ring. In some embodiments, the first element (F1) of the first compound is attached to a first fused ring system.
In some embodiments, the FS1 of the first compound is attached to an unsaturated carbon atom. In some embodiments, the FS1 of the first compound is attached to a saturated carbon atom. In some embodiments, the FS1 of the first compound is attached to a Si or Ge atom. In some embodiments, the FS1 of the first compound is attached to a first ring. In some embodiments, the FS1 of the first compound is attached to a first fused ring system.
In some embodiments, the first element (S1) of the second compound is attached to an unsaturated carbon atom. In some embodiments, the first element (S1) of the second compound is attached to a saturated carbon atom. In some embodiments, the first element (S1) of the second compound is attached to a Si or Ge atom. In some embodiments, the first element (S1) of the second compound is attached to a first ring. In some embodiments, the first element (S1) of the second compound is attached to a first fused ring system.
In some embodiments, the SS1 of the second compound is attached to an unsaturated carbon atom. In some embodiments, the SS1 of the second compound is attached to a saturated carbon atom. In some embodiments, the SS1 of the second compound is attached to a Si or Ge atom. In some embodiments, the SS1 of the second compound is attached to a first ring. In some embodiments, the SS1 of the second compound is attached to a first fused ring system.
In some embodiments, the second element (F2) of the first compound is attached to an unsaturated carbon atom. In some embodiments, the second element (F2) of the first compound is attached to a saturated carbon atom. In some embodiments, the second element (F2) of the first compound is attached to a Si or Ge atom. In some embodiments, the second element (F2) of the first compound is attached to a first ring. In some embodiments, the second element (F2) of the first compound is attached to a first fused ring system.
In some embodiments, the FS2 of the first compound is attached to an unsaturated carbon atom. In some embodiments, the FS2 of the first compound is attached to a saturated carbon atom. In some embodiments, the FS2 of the first compound is attached to a Si or Ge atom. In some embodiments, the FS2 of the first compound is attached to a first ring. In some embodiments, the FS2 of the first compound is attached to a first fused ring system.
In some embodiments, the second element (S2) of the second compound is attached to an unsaturated carbon atom. In some embodiments, the second element (S2) of the second compound is attached to a saturated carbon atom. In some embodiments, the second element (S2) of the second compound is attached to a Si or Ge atom. In some embodiments, the second element (S2) of the second compound is attached to a first ring. In some embodiments, the second element (S2) of the second compound is attached to a first fused ring system.
In some embodiments, the SS2 of the second compound is attached to an unsaturated carbon atom. In some embodiments, the SS2 of the second compound is attached to a saturated carbon atom. In some embodiments, the SS2 of the second compound is attached to a Si or Ge atom. In some embodiments, the SS2 of the second compound is attached to a first ring. In some embodiments, the SS2 of the second compound is attached to a first fused ring system.
In some embodiments, the third element (F3) of the first compound is attached to an unsaturated carbon atom. In some embodiments, the third element (F3) of the first compound is attached to a saturated carbon atom. In some embodiments, the third element (F3) of the first compound is attached to a Si or Ge atom. In some embodiments, the third element (F3) of the first compound is attached to a first ring. In some embodiments, the third element (F3) of the first compound is attached to a first fused ring system.
In some embodiments, the FS3 of the first compound is attached to an unsaturated carbon atom. In some embodiments, the FS3 of the first compound is attached to a saturated carbon atom. In some embodiments, the FS3 of the first compound is attached to a Si or Ge atom. In some embodiments, the FS3 of the first compound is attached to a first ring. In some embodiments, the FS3 of the first compound is attached to a first fused ring system.
In some embodiments, the third element (S3) of the second compound is attached to an unsaturated carbon atom. In some embodiments, the third element (S3) of the second compound is attached to a saturated carbon atom. In some embodiments, the third element (S3) of the second compound is attached to a Si or Ge atom. In some embodiments, the third element (S3) of the second compound is attached to a first ring. In some embodiments, the third element (S3) of the second compound is attached to a first fused ring system.
In some embodiments, the SS3 of the second compound is attached to an unsaturated carbon atom. In some embodiments, the SS3 of the second compound is attached to a saturated carbon atom. In some embodiments, the SS3 of the second compound is attached to a Si or Ge atom. In some embodiments, the SS3 of the second compound is attached to a first ring. In some embodiments, the SS3 of the second compound is attached to a first fused ring system.
In some embodiments, both the first compound and the second compound are non-metal-containing compounds.
In some embodiments, the first compound is a non-metal-containing compound; the second compound is a metal-containing compound.
In some embodiments, both the first compound and the second compound are metal-containing compounds.
In some embodiments, the OLED comprises an EML disposed between the first electrode and the second electrode; wherein the EML comprises a first emitter; wherein the first emitter can be a phosphorescent or fluorescent emitter. Phosphorescence generally refers to emission of a photon with a change in electron spin, i.e., the initial and final states of the emission have different multiplicity, such as from T1 to S0 state. Ir and Pt complexes currently widely used in the OLED belong to phosphorescent emitters. In some embodiments, if an exciplex formation involves a triplet emitter, such exciplex can also emit phosphorescent light. On the other hand, fluorescent emitters generally refer to emission of a photon without a change in electron spin, such as from S1 to S0 state. Fluorescent emitters can be delayed fluorescent or non-delayed fluorescent emitters. Depending on the spin state, fluorescent emitter can be a singlet emitter or a doublet emitter, or other multiplet emitter. It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistics limit through delayed fluorescence. There are two types of delayed fluorescence, i.e. P-type and E-type delayed fluorescence. P-type delayed fluorescence is generated from triplet-triplet annihilation (TTA). On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the thermal population between the triplet states and the singlet excited states. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). E-type delayed fluorescence characteristics can be found in an exciplex system or in a single compound. Without being bound by theory, it is believed that TADF requires a compound or an exciplex having a small singlet-triplet energy gap (ΔES-T) less than or equal to 300, 250, 200, 150, 100, or 50 meV. There are two major types of TADF emitters, one is called donor-acceptor type TADF, the other one is called multiple resonance (MR) TADF. Often, donor-acceptor single compounds are constructed by connecting an electron donor moiety such as amino- or carbazole-derivatives and an electron acceptor moiety such as N-containing six-membered aromatic ring. Donor-acceptor exciplex can be formed between a hole transporting compound and an electron transporting compound. The examples for MR-TADF include a highly conjugated boron-containing compounds. In some embodiments, the reverse intersystem crossing time from T1 to S1 of the delayed fluorescent emission at 293K is less than or equal to 10 microseconds. In some embodiments, such time can be greater than 10 microseconds and less than 100 microseconds
In some embodiment, the first emitter is capable of emitting light from a triplet excited state to a ground singlet state in an OLED at room temperature.
In some embodiments, the first emitter is a metal coordination complex having a metal-carbon bond.
In some embodiments, the first emitter is a metal coordination complex having a metal-nitrogen bond.
In some embodiments, the first emitter is a metal coordination complex having a metal-oxygen bond.
In some embodiments, the metal is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu.
In some embodiments, the metal is Ir.
In some embodiments, the metal is Pt.
In some embodiments, the first emitter has the formula of M(L1)x(L2)y(L3)z;
In some embodiments, the first emitter has a formula selected from the group consisting of Ir(LA)3, Ir(LA)(LB)2, Ir(LA)2(LB), Ir(LA)2(LC), Ir(LA)(LB)(LC), and Pt(LA)(LB);
In some embodiments, the first emitter has a formula selected from the group consisting of the structures in the following LIST E3:
In some embodiments, the first emitter has a formula selected from the group consisting of the structures in the following LIST E4:
In some embodiments of heteroleptic compound having the formula of M(L1)x(L2)y(L3)z as defined above, the ligand L1 has a first substituent RI, where the first substituent RI has a first atom a-I that is the farthest away from the metal M among all atoms in the ligand LA. Additionally, the ligand L2, if present, has a second substituent RI, where the second substituent RII has a first atom a-II that is the farthest away from the metal M among all atoms in the ligand L2. Furthermore, the ligand L3, if present, has a third substituent RIII, where the third substituent RIII has a first atom a-III that is the farthest away from the metal M among all atoms in the ligand L3.
In such heteroleptic compounds, vectors VD1, VD2, and VD3 can be defined as follows. VD1 represents the direction from the metal M to the first atom a-I and the vector VD1 has a value D1 that represents the straight line distance between the metal M and the first atom a-I in the first substituent RI. VD2 represents the direction from the metal M to the first atom a-II and the vector VD2 has a value D2 that represents the straight line distance between the metal M and the first atom a-II in the second substituent RII. VD3 represents the direction from the metal M to the first atom a-III and the vector VD3 has a value D3 that represents the straight line distance between the metal M and the first atom a-III in the third substituent RIII.
In such heteroleptic compounds, a sphere having a radius r is defined whose center is the metal M and the radius r is the smallest radius that will allow the sphere to enclose all atoms in the compound that are not part of the substituents RI, RII and RIII; and where at least one of D1, D2, and D3 is greater than the radius r by at least 1.5 Å. In some embodiments, at least one of D1, D2, and D3 is greater than the radius r by at least 2.9, 3.0, 4.3, 4.4, 5.2, 5.9, 7.3, 8.8, 10.3, 13.1, 17.6, or 19.1 Å.
In some embodiments of such heteroleptic compound, the compound has a transition dipole moment axis and angles are defined between the transition dipole moment axis and the vectors VD1, VD2, and VD3, where at least one of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 is less than 40°. In some embodiments, at least one of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 is less than 30°. In some embodiments, at least one of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 is less than 20°. In some embodiments, at least one of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 is less than 15°. In some embodiments, at least one of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 is less than 10°. In some embodiments, at least two of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 are less than 20°. In some embodiments, at least two of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 are less than 15°. In some embodiments, at least two of the angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 are less than 10°.
In some embodiments, all three angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 are less than 20°. In some embodiments, all three angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 are less than 15°. In some embodiments, all three angles between the transition dipole moment axis and the vectors VD1, VD2, and VD3 are less than 10°.
In some embodiments of such heteroleptic compounds, the compound has a vertical dipole ratio (VDR) of 0.33 or less. In some embodiments of such heteroleptic compounds, the compound has a VDR of 0.30 or less. In some embodiments of such heteroleptic compounds, the compound has a VDR of 0.25 or less. In some embodiments of such heteroleptic compounds, the compound has a VDR of 0.20 or less. In some embodiments of such heteroleptic compounds, the compound has a VDR of 0.15 or less.
One of ordinary skill in the art would readily understand the meaning of the terms transition dipole moment axis of a compound and vertical dipole ratio of a compound. Nevertheless, the meaning of these terms can be found in U.S. Pat. No. 10,672,997 whose disclosure is incorporated herein by reference in its entirety. In U.S. Pat. No. 10,672,997, horizontal dipole ratio (HDR) of a compound, rather than VDR, is discussed. However, one skilled in the art readily understands that VDR=1−HDR.
In some embodiments, the OLED comprises an EML disposed between the first electrode and the second electrode; wherein the EML comprises a first emitter; and wherein the first emitter is capable of functioning as a delayed fluorescent emitter in an OLED at room temperature.
In some embodiments, the first emitter is capable of functioning as a thermal activated delayed fluorescent emitter in an OLED at room temperature.
In some embodiments, the first emitter comprises at least one donor group and at least one acceptor group.
In some embodiments, wherein the first emitter is a metal complex.
In some embodiments, the first emitter is a non-metal complex.
In some embodiments, the first emitter is a Cu, Ag, or Au complex.
In some embodiments, the first emitter has the formula of M(L5)(L6), wherein M is Cu, Ag, or Au, L5 and L6 are different, and L5 and L6 are independently selected from the group consisting of the following structures (LIST E5):
In some embodiments of the OLED, the TADF emitter may be one of the following:
In some embodiments of the OLED, the TADF emitter is selected from the group consisting of the structures in the following TADF LIST:
In some embodiments, the first emitter comprises at least one of the chemical moieties selected from the group consisting of the structures in the following LIST E6:
In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments, the first emitter comprises at least one of the chemical moieties selected from the group consisting of nitrile, isonitrile, borane, fluoride, pyridine, pyrimidine, pyrazine, triazine, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-triphenylene, imidazole, pyrazole, oxazole, thiazole, isoxazole, isothiazole, triazole, thiadiazole, and oxadiazole. In some embodiments, the acceptor moieties and the donor moieties as described herein can be connected directly, through a conjugated linker, or a non-conjugated linker, such as a sp3 carbon or silicon atom.
In some embodiments, the OLED comprises an EML disposed between the first electrode and the second electrode; wherein the EML comprises a first emitter; and wherein the first emitter is capable of functioning as a fluorescent emitter in an OLED at room temperature.
In some embodiments, the first emitter comprises at least one organic group selected from the group consisting of the structures in the following LIST A1:
In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments of the OLED, the first emitter is selected from the group consisting of the structures in the following LIST A2:
In some embodiments, the first emitter is selected from the group consisting of the structures of the following LIST:
In some embodiments, the first emitter is selected from the group consisting of the structures of the ACCEPTOR LIST 1 as defined herein.
In some embodiments, the OLED comprises an EML disposed between the first electrode and the second electrode; wherein the EML comprises a first emitter; and wherein the first emitter comprises a lanthanide metal.
In some embodiments, the first layer may be an emissive layer and the first compound as described herein may be an emissive dopant or a non-emissive dopant. In some embodiments, the first layer may be an emissive layer and the second compound as described herein may be an emissive dopant or a non-emissive dopant. In some embodiments, the first layer may be an emissive layer and the third compound as described herein may be an emissive dopant or a non-emissive dopant.
In some embodiments, the OLED comprises an emissive region disposed between the first electrode and the second electrode; the emissive region can involve a sensitizing process. For example, the first compound can be a sensitizer compound that transfer energy to the second compound, and the second compound can be an acceptor which is an emitter. In some embodiments, the sensitizer compound is capable of emitting light from a triplet excited state to a ground singlet state in an OLED at room temperature. In some embodiments, the sensitizer compound is capable of functioning as a phosphorescent emitter, a TADF emitter, or a doublet emitter in an OLED at room temperature. In some embodiments, the acceptor compound is selected from the group consisting of: a delayed-fluorescent compound functioning as a TADF emitter in the OLED at room temperature, a fluorescent compound functioning as a fluorescent emitter in the OLED at room temperature. In some embodiments of the OLED, the sensitizer and acceptor compounds are in separate layers within the emissive region. In some embodiments, the sensitizer and the acceptor compounds are present as a mixture in one or more layers in the emissive region. It should be understood that the mixture in a given layer can be a homogeneous mixture or the compounds in the mixture can be in graded concentrations through the thickness of the given layer. The concentration grading can be linear, non-linear, sinusoidal, etc. When there are more than one layer in the emissive region having a mixture of the sensitizer and the acceptor compounds, the type of mixture (i.e., homogeneous or graded concentration) and the concentration levels of the compounds in the mixture in each of the more than one layer can be the same or different. In addition to the sensitizer and the acceptor compounds, there can be one or more other functional compounds such as, but not limit to, hosts also mixed into the mixture.
In some embodiments, the acceptor compound can be in two or more layers with the same or different concentration. In some embodiments, when two or more layers contain the acceptor compound, the concentration of the acceptor compound in at least two of the two or more layers are different. In some embodiments, the concentration of sensitizer compound in the layer containing the sensitizer compound is in the range of 1 to 50%, 10 to 20%, or 12-15% by weight. In some embodiments, the concentration of the acceptor compound in the layer containing the acceptor compound is in the range of 0.1 to 10%, 0.5 to 5%, or 1 to 3% by weight.
In some embodiments, the emissive region contains N layers where N>2. In some embodiments, the sensitizer compound is present in each of the N layers, and the acceptor compound is contained in fewer than or equal to N−1 layers. In some embodiments, the sensitizer compound is present in each of the N layers, and the acceptor compound is contained in fewer than or equal to N/2 layers. In some embodiments, the acceptor compound is present in each of the N layers, and the sensitizer compound is contained in fewer than or equal to N−1 layers. In some embodiments, the acceptor compound is present in each of the N layers, and the sensitizer compound is contained in fewer than or equal to N/2 layers.
In some embodiments, the OLED emits a luminescent emission comprising an emission component from the S1 energy (the first singlet energy) of the acceptor compound when a voltage is applied across the OLED. In some embodiments, at least 65%, 75%, 85%, or 95% of the emission from the OLED is produced from the acceptor compound with a luminance of at least 10 cd/m2. In some embodiments, Si energy of the acceptor compound is lower than that of the sensitizer compound.
In some embodiments, a T1 energy (the first triplet energy) of the host compound is higher than the T1 energies of the sensitizer compound and the acceptor compound. In some embodiments, S1-T1 energy gap of the sensitizer compound and/or acceptor compound is less than 400, 300, 250, 200, 150, 100, or 50 meV.
In some embodiments where the sensitizer compound provides unicolored sensitization (i.e., minimal loss in energy upon energy transfer to the acceptor compound), the acceptor compound has a Stokes shift of 30, 25, 20, 15, or 10 nm or less. An example would be a broad blue phosphor sensitizing a narrow blue emitting acceptor
In some embodiments where the sensitizer compound provides a down conversion process (e.g., a blue emitter being used to sensitize a green emitter, or a green emitter being used to sensitize a red emitter), the acceptor compound has a Stokes shift of 30, 40, 60, 80, or 100 nm or more.
One way to quantify the qualitative relationship between a sensitizer compound (a compound to be used as the sensitizer in the emissive region of the OLED of the present disclosure) and an acceptor compound (a compound to be used as the acceptor in the emissive region of the OLED of the present disclosure) is by determining a value Δλ=λmax1−λmax2, where λmax1 and λmax2 are defined as follows. λmax1 is the emission maximum of the sensitizer compound at room temperature when the sensitizer compound is used as the sole emitter in a first monochromic OLED (an OLED that emits only one color) that has a first host. λmax2 is the emission maximum of the acceptor compound at room temperature when the acceptor compound is used as the sole emitter in a second monochromic OLED that has the same first host.
In some embodiments of the OLED of the present disclosure where the sensitizer compound provides unicolored sensitization (i.e., minimal loss in energy upon energy transfer to the acceptor compound), Δλ (determined as described above) is equal to or less than the number selected from the group consisting of 15, 12, 10, 8, 6, 4, 2, 0, −2, −4, −6, −8, and −10 nm.
In some embodiments where the emission of the acceptor is redshifted by the sensitization, Δλ is equal to or greater than the number selected from the group consisting of 20, 30, 40, 60, 80, 100 nm.
In some embodiments, the emissive region comprises the third compound which can be a host.
In some embodiments, the first layer further comprises an additional host, wherein the additional host comprises a triphenylene containing benzo-fused thiophene or benzo-fused furan; wherein any substituent in the host is an unfused substituent independently selected from the group consisting of CnH2n+1, OCnH2n+1, OAr1, N(CnH2n+1)2, N(Ar1)(Ar2), CH═CH—CnH2n+1, C≡CCnH2n+1, Ar1, Ar1—Ar2, CnH2n—Ar1, or no substitution;
In some embodiments, the organic layer may further comprise an additional host, wherein the additional host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, 5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, azaborinine, oxaborinine, dihydroacridine, xanthene, dihydrobenzoazasiline, dibenzooxasiline, phenoxazine, phenoxathiine, phenothiazine, dihydrophenazine, fluorene, naphthalene, anthracene, phenanthrene, phenanthroline, benzoquinoline, quinoline, isoquinoline, quinazoline, pyrimidine, pyrazine, pyridine, triazine, boryl, silyl, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, and aza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).
In some embodiments, the additional host can be selected from the group consisting of the structures of the following HOST Group 1:
In some embodiments, at least one of R, R′, RA′, RB′, RC′, RD′, RE′, RF′, and RG′ comprises a structure selected from LIST A3.
In some embodiments, L′ is an organic linker selected from the group consisting of BR, BRR′, NR, PR, P(O)R, O, S, Se, C═O, C═S, C═Se, C═NR, C═CRR′, S═O, SO2, CR, CRR′, SiRR′, GeRR′, alkylene, cycloalkyl, aryl, cycloalkylene, arylene, heteroarylene, and combinations thereof.
In some embodiments at least one of J1 to J3 is N. In some embodiments at least two of J1 to J3 are N. In some embodiments, all three of J1 to J3 are N. In some embodiments, each YCC and YDD is independently O, S, or SiRR′, or more preferably O or S. In some embodiments, at least one unsubstituted aromatic carbon atom is replaced with N to form an aza-ring.
In some embodiments, the host is selected from the group consisting of EG1-MG1-EG1 to EG53-MG27-EG53 with a formula of EGa-MGb-EGc, or EG1-EG1 to EG53-EG53 with a formula of EGa-EGc when MGb is absent, wherein a is an integer from 1 to 53, b is an integer from 1 to 27, c is an integer from 1 to 53. The structure of EG1 to EG53 is shown below:
The structures of MG1 to MG27 are shown below:
In the MGb structures shown above, the two bonding positions in the asymmetric structures MG1, MG11, MG12, MG13, MG14, MG17, MG24, and MG25 are labeled with numbers for identification purposes.
In some embodiments, the host can be any of the aza-substituted variants thereof, fully or partially deuterated variants thereof, and combinations thereof. In some embodiments, the host has formula EGa-MGb-Egc and is selected from the group consisting of h1 to h112 defined in the following HOST Group 2 list, where each of MGb, EGa, and EGc are defined as follows:
In some embodiments, the additional host can be selected from the group consisting of:
partially or fully deuterated variants thereof and combinations thereof.
In some embodiments, the first layer can further comprise an additional host, wherein the additional host comprises a metal complex.
In some embodiments, the first compound and/or the second compound and/or third compound as described herein may be a sensitizer; wherein the device may further comprise an acceptor; and wherein the acceptor may be selected from the group consisting of fluorescent emitter, delayed fluorescence emitter, and combination thereof.
In yet another aspect, the present disclosure provides an OLED comprising a light emitting stack that comprises: a first electrode; a second electrode; a first layer disposed between the first electrode and the second electrode; wherein the first layer is selected from the group consisting of hole injecting layer (HIL), hole transporting layer (HTL), electron blocking layer (EBL), emissive layer (EML), hole blocking layer (HBL), electron transporting layer (ETL), and electron injecting layer (EIL); wherein the first layer comprises a first compound, a second compound, and a third compound; wherein the first compound comprises a first element (F1) selected from group one consisting of D, F, CN, Si, Ge, P, B, and Se; wherein the second compound comprises a first element (S1) selected from the group one; and wherein the first element (F1) of the first compound can be same or different from the first element (S1) of the second compound; wherein one of the first compound, second compound, or third compound is selected from a phosphorescent capable material or thermally activated delayed fluorescent capable material; wherein one of the first compound, second compound, or third compound is selected from a fluorescent material or thermally activated delayed fluorescent capable material; and wherein one of the first compound, second compound, or third compound is a host material.
In some embodiments, the first compound is a phosphorescent capable material. In some embodiments, the first compound is a phosphorescent capable material which comprises Si, B, or D. In some embodiments, the first compound is a TADF capable material which comprises Si, B, or D. In some embodiments, the first compound is a TADF capable material.
In some embodiments, the second compound is a Host. In some embodiments, the second compound is a Host which comprises Si, B, or D. In some embodiments, the second compound is a Fluorophore. In some embodiments, the second compound is a Fluorophore which comprises Si. CN, B, or D.
In some embodiments, the first compound is a phosphorescent capable material and the second compound is a Host. In some embodiments, the first compound is a phosphorescent capable material and the second compound is a Fluorophore. In some embodiments, the first compound is a TADF capable material and the second compound is a Host. In some embodiments, the first compound is a TADF capable material and the second compound is a Fluorophore. In some embodiments, the first compound is a phosphorescent capable material and the second compound is a TADF capable material. In some embodiments, the first compound is a fluorophore and the second compound is a Host.
In some embodiments, the third compound comprises a third element (T1) selected from the group one consisting of D, F, CN, Si, Ge, P, B, and Se.
In some embodiments, the host comprises Si and D, Si and B, or CN and D.
In some embodiments, the dopant comprises Si and D, Si and CN.
In some embodiments, the fluorophore comprises B and D, B and Si, B and CN, Si and D, B and D and Si, B and D and CN.
In some embodiments, each of the first, the second, and the third compounds comprises one of Si, B, D.
In some embodiments, each of the first, the second, and the third compounds comprises at least one atom of the same element selected from Si, B, D.
In some embodiments, each of the first, the second, and the third compounds comprises at least one atom of the different element selected from Si, B, D.
In some embodiments, each of the first, the second, and the third compounds comprises comprises at least one Si and at least on D.
In some embodiments, two of the first, the second, and the third compounds comprise B.
In some embodiments, two of the first, the second, and the third compounds comprise Si.
In some embodiments, two of the first, the second, and the third compounds comprise D.
In some of these embodiments, the phosphorescent capable material may be selected from the structures of LIST E3 and LIST E4 as defined herein.
In some embodiments LIST E3 and LIST E4, at least one of R, R′, R″, R′″, R10a, R11a, R12a, R13a, R20a, R30a, R40a, R50a, R60, R70, R97, R98, R99, RA1′, RA2′, RA″, RB″, RC″, RD″, RE″, RF″, RG″, RH″, RI″, RJ″, RK″, RL″, RM″, and RN″ comprises a structure selected from the group consisting of the structures of LIST A3 defined herein.
In some of these embodiments, the fluorescent compound comprises at least one of the chemical moieties selected from the group consisting of the structures of LIST A1 defined herein:
In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments, the fluorescent compound is selected from the group consisting of the structures of LIST A2 as defined herein:
In some embodiments, at least one of R, RF1, and R1S to R9S comprises a structure selected from LIST A3.
In some embodiments, at least one of R, R′, R″, R′″, R10a, R11a, R12a, R13a, R20a, R30a, R40a, R50a, R60, R70, R97, R98, R99, RA1′, RA2′, RA″, RB″, RC″, RD″, RE″, RF″, RG″, RH″, RI″, RJ″, RK″, RL″, RM″, and RN″ of LIST E3 and LIST E4 and the at least one of RF1, and R1S to R9S of the above fluorescent acceptor LIST A2 independently comprise a group selected from the LIST A3 defined below:
In some embodiments, the fluorescent material may be selected from the structures of the following LIST A4:
In some embodiments, the TADF emitter comprises at least one of the chemical moieties selected from the group consisting of nitrile, isonitrile, borane, fluoride, pyridine, pyrimidine, pyrazine, triazine, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-triphenylene, imidazole, pyrazole, oxazole, thiazole, isoxazole, isothiazole, triazole, thiadiazole, and oxadiazole.
In some embodiments, the emissive layer further includes a fourth compound. In some embodiments, the fourth compound is a host. In some embodiments, the fourth compound is an H-host.
In some embodiments, the emissive layer comprises a plurality of emissive layers and at least one of the plurality of emissive layers comprises both the first and second compounds.
In some embodiments, the emissive layer comprises a plurality of emissive layers, and each of the plurality of emissive layers emits only a single color.
In some embodiments, the OLED further comprises at least one layer from the group consisting of a hole injection layer, a hole transport layer, an electron blocking layer, an emission material layer, a hole blocking layer, an electron transport layer, electron injection layer and a capping layer.
In some embodiments, an OLED of the present disclosure comprises an emissive region disposed between the anode and the cathode; wherein the emissive region comprises a sensitizer compound and an acceptor compound; wherein the sensitizer transfers energy to the acceptor compound that is an emitter. In some embodiments, the sensitizer compound is capable of emitting light from a triplet excited state to a ground singlet state in an OLED at room temperature. In some embodiments, the sensitizer compound is capable of functioning as a phosphorescent emitter, a TADF emitter, or a doublet emitter in an OLED at room temperature. In some embodiments, the acceptor compound is selected from the group consisting of: a delayed-fluorescent compound functioning as a TADF emitter in the OLED at room temperature, a fluorescent compound functioning as a fluorescent emitter in the OLED at room temperature. In some embodiments, the fluorescent emitter can be a singlet or doublet emitters. In some of such embodiments, the singlet emitter can also include a TADF emitter, furthermore, a multi-resonant MR-TADF emitter. Description of the delayed fluorescence as used herein can be found in U.S. application publication US20200373510A1, at paragraphs 0083-0084, the entire contents of which are incorporated herein by reference.
In some embodiments of the OLED, the sensitizer and acceptor compounds are in separate layers within the emissive region.
In some embodiments, the sensitizer and the acceptor compounds are present as a mixture in one or more layers in the emissive region. It should be understood that the mixture in a given layer can be a homogeneous mixture or the compounds in the mixture can be in graded concentrations through the thickness of the given layer. The concentration grading can be linear, non-linear, sinusoidal, etc. When there are more than one layer in the emissive region having a mixture of the sensitizer and the acceptor compounds, the type of mixture (i.e., homogeneous or graded concentration) and the concentration levels of the compounds in the mixture in each of the more than one layer can be the same or different. In addition to the sensitizer and the acceptor compounds, there can be one or more other functional compounds such as, but not limit to, hosts also mixed into the mixture.
In some embodiments, the acceptor compound can be in two or more layers with the same or different concentration. In some embodiments, when two or more layers contain the acceptor compound, the concentration of the acceptor compound in at least two of the two or more layers are different. In some embodiments, the concentration of sensitizer compound in the layer containing the sensitizer compound is in the range of 1 to 50%, 10 to 20%, or 12-15% by weight. In some embodiments, the concentration of the acceptor compound in the layer containing the acceptor compound is in the range of 0.1 to 10%, 0.5 to 5%, or 1 to 3% by weight.
In some embodiments, the emissive region contains N layers where N>2. In some embodiments, the sensitizer compound is present in each of the N layers, and the acceptor compound is contained in fewer than or equal to N−1 layers. In some embodiments, the sensitizer compound is present in each of the N layers, and the acceptor compound is contained in fewer than or equal to N/2 layers. In some embodiments, the acceptor compound is present in each of the N layers, and the sensitizer compound is contained in fewer than or equal to N−1 layers. In some embodiments, the acceptor compound is present in each of the N layers, and the sensitizer compound is contained in fewere than or equal to N/2 layers.
In some embodiments, the OLED emits a luminescent emission comprising an emission component from the Si energy (the first singlet energy) of the acceptor compound when a voltage is applied across the OLED. In some embodiments, at least 65%, 75%, 85%, or 95% of the emission from the OLED is produced from the acceptor compound with a luminance of at least 10 cd/m2. In some embodiments, Si energy of the acceptor compound is lower than that of the sensitizer compound.
In some embodiments, a T1 energy (the first triplet energy) of the host compound is greater than or equal to the T1 energies of the sensitizer compound and the acceptor compound, and the T1 energy of the sensitizer compound is greater than or equal to the S1 energy (the first singlet energy) of the acceptor compound. In some embodiments, S1-T1 energy gap of the sensitizer compound, and/or acceptor compound, and/or first host compound, and/or second host compound is less than 400, 300, 250, 200, 150, 100, or 50 meV. In some embodiments, the absolute energy difference between the HOMO of the sensitizer compound and the HOMO of the acceptor compound is less than 0.6, 0.5, 0.4, 0.3, or 0.2 eV. In some embodiments, the absolute energy difference between the LUMO of the sensitizer compound and the LUMO of the acceptor compound is less than 0.6, 0.5, 0.4, 0.3, or 0.2 eV.
In some embodiments where the sensitizer compound provides unicolored sensitization (i.e., minimal loss in energy upon energy transfer to the acceptor compound), the acceptor compound has a Stokes shift of 30, 25, 20, 15, or 10 nm or less. An example would be a broad blue phosphor sensitizing a narrow blue emitting acceptor
In some embodiments where the sensitizer compound provides a down conversion process (e.g., a blue emitter being used to sensitize a green emitter, or a green emitter being used to sensitize a red emitter), the acceptor compound has a Stokes shift of 30, 40, 60, 80, or 100 nm or more.
In some embodiments, the difference between λmax of the emission spectrum of compound S1 and λmax of the absorption spectrum of the compound A1 is 50, 40, 30, or 20 nm or less. In some embodiments, the spectral overlap of the light absorbing area of the compound A1 and the light emitting area of the compound S1, relative to the light emitting area of the compound S1, is greater than 5%, 10%, 15%, 20%, 30%, 40%, 50%, or more.
One way to quantify the qualitative relationship between a sensitizer compound (a compound to be used as the sensitizer in the emissive region of the OLED of the present disclosure) and an acceptor compound (a compound to be used as the acceptor in the emissive region of the OLED of the present disclosure) is by determining a value Δλ=λmax1−λmax2, where λmax1 and λmax2 are defined as follows. λmax1 is the emission maximum of the sensitizer compound at room temperature when the sensitizer compound is used as the sole emitter in a first monochromic OLED (an OLED that emits only one color) that has a first host. λmax2 is the emission maximum of the acceptor compound at room temperature when the acceptor compound is used as the sole emitter in a second monochromic OLED that has the same first host.
In some embodiments of the OLED of the present disclosure where the sensitizer compound provides unicolored sensitization (i.e., minimal loss in energy upon energy transfer to the acceptor compound), Δλ (determined as described above) is equal to or less than the number selected from the group consisting of 15, 12, 10, 8, 6, 4, 2, 0, −2, −4, −6, −8, and −10 nm.
In some embodiments, a spectral overlap integral of compound A1 and compound S1 is at least 1014 nm4*L/cm*mol. In some embodiments, a spectral overlap integral of compound A1 and compound S1 is at least 5×1014 nm4*L/cm*mol. In some embodiments, a spectral overlap integral of compound A1 and compound S1 is at least 1015 nm4*L/cm*mol.
As used herein, “spectral overlap integral” is determined by multiplying the compound A1 extinction spectrum by the compound Si emission spectrum normalized with respect to the area under the curve. The higher the spectral overlap, the better the Förster Resonance Energy Transfer (FRET) efficiency. The rate of FRET is proportional to the spectral overlap integral. Therefore, a high spectral overlap can help improve the FRET efficiency and reduce the exciton lifetime in an OLED.
In some embodiments, compound A1 and compound S1 are selected in order to increase the spectral overlap. Increasing the spectral overlap can be achieved in several ways, for example, increasing the oscillator strength of compound A1, minimizing the distance between the compound S1 peak emission intensity and the compound A1 absorption peak, and narrowing the line shape of the compound S1 emission or the compound A1 absorption. In some embodiments, the oscillator strength of compound A1 is greater than or equal to 0.1.
In some embodiments where the emission of the acceptor is redshifted by the sensitization, Δλ is equal to or greater than the number selected from the group consisting of 20, 30, 40, 60, 80, 100 nm.
In the embodiments, the sensitizer compound is capable of functioning as a phosphorescent emitter in an OLED at room temperature, and the sensitizer compound can be a metal coordination complex having a metal-carbon bond, a metal-nitrogen bond, or a metal-oxygen bond. In some embodiments, the metal is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, and Cu. In some embodiments, the metal is Ir. In some embodiments, the metal is Pt. In some embodiments, the sensitizer compound has the formula of M(LA)x(LB)y(LC)z;
In some embodiments, the metal in formula M(LA)x(LB)y(LC)z is selected from the group consisting of Cu, Ag, or Au.
In some embodiments of the OLED, the sensitizer compound has a formula selected from the group consisting of Ir(LA)3, Ir(LA)(LB)2, Ir(LA)2(LB), Ir(LA)2(LC), Ir(LA)(LB)(LC), and Pt(LA)(LB);
In some embodiments of the OLED, the sensitizer compound is selected from the group consisting of the compounds of LIST E1 and LIST E2 as defined herein; wherein:
In some embodiments of the OLED where the sensitizer is selected from the group consisting of the structures in the SENSITIZER LIST, one or more of R, R′, R″, R′″, R10a, R11a, R12a, R13a, R20a, R30a, R40a, R50a, R60, R70, R97, R98, R99, RA1′, RA2′, RA″, RB″, RC″, RD″, RE″, RF″, RG″, RH″, RI″, RJ″, RK″, RL″, RM″, and RN″ comprises a moiety selected from the group consisting of fully or partially deuterated aryl, fully or partially deuterated alkyl, boryl, silyl, germyl, 2,6-terphenyl, 2-biphenyl, 2-(tert-butyl)phenyl, tetraphenylene, tetrahydronaphthalene, and combinations thereof.
In some embodiments, the sensitizer and/or the acceptor can be a phosphorescent or fluorescent emitter. Phosphorescence generally refers to emission of a photon with a change in electron spin, i.e., the initial and final states of the emission have different multiplicity, such as from T1 to S0 state. Ir and Pt complexes currently widely used in OLEDs belong to a family of phosphorescent emitters. In some embodiments, if an exciplex formation involves a triplet emitter, such exciplex can also emit phosphorescent light. On the other hand, fluorescent emitters generally refer to emission of a photon without a change in electron spin, such as from S1 to S0 state. Fluorescent emitters can be delayed fluorescent or non-delayed fluorescent emitters. Depending on the spin state, fluorescent emitter can be a singlet emitter or a doublet emitter, or other multiplet emitter. It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistics limit through delayed fluorescence. There are two types of delayed fluorescence, i.e. P-type and E-type delayed fluorescence. P-type delayed fluorescence is generated from triplet-triplet annihilation (TTA). On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the thermal population between the triplet states and the singlet excited states. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). E-type delayed fluorescence characteristics can be found in an exciplex system or in a single compound. Without being bound by a theory, it is believed that TADF requires a compound or an exciplex having a small singlet-triplet energy gap (ΔES-T) of less than or equal to 300 meV, and in some preferred embodiments, less than or equal to 250, 200, 150, 100, or 50 meV. There are two major types of TADF emitters, one is called donor-acceptor type TADF, the other one is called multiple resonance (MR) type TADF. Often, donor-acceptor single compounds are constructed by connecting an electron donor moiety such as amino- or carbazole-derivatives and an electron acceptor moiety such as N-containing six-membered aromatic ring. Donor-acceptor exciplex can be formed between a hole transporting compound and an electron transporting compound. The examples for MR-TADF include a highly conjugated boron-containing compounds. In some embodiments, the reverse intersystem crossing time duration from T1 to Si of the delayed fluorescent emission at 293K is less than or equal to 10 microseconds. In some embodiments, such time duration can be greater than 10 microseconds and less than 100 microseconds.
In some embodiments of the OLED, at least one of the following conditions is true:
In some embodiments of the OLED, the TADF emitter comprises at least one donor group and at least one acceptor group. In some embodiments, the TADF emitter is a metal complex. In some embodiments, the TADF emitter is a non-metal complex. In some embodiments, the TADF emitter is a Cu, Ag, or Au complex.
In some embodiments of the OLED, the TADF emitter has the formula of M(L5)(L6), wherein M is Cu, Ag, or Au, L5 and L6 are different, and L5 and L6 are independently selected from the group consisting of the structures of LIST E5 as defined herein.
In some embodiments of the OLED, the TADF emitter is selected from the group consisting of the structures in TADF LIST as defined herein.
In some embodiments of the OLED, the TADF emitter comprises at least one of the chemical moieties selected from the group consisting of the structures of LIST E6 as defined herein.
In some of the above embodiments of LIST E6, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments, the TADF emitter comprises at least one of the chemical moieties selected from the group consisting of nitrile, isonitrile, borane, fluoride, pyridine, pyrimidine, pyrazine, triazine, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-triphenylene, imidazole, pyrazole, oxazole, thiazole, isoxazole, isothiazole, triazole, thiadiazole, and oxadiazole.
In some embodiments, the acceptor is a fluorescent compound functioning as an emitter in the OLED at room temperature. In some embodiments, the fluorescent compound comprises at least one of the chemical moieties selected from the group consisting of the structures of LIST A1 as defined herein. In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments of the OLED, the fluorescent compound is selected from the group consisting of the structures of LIST A2 as defined herein.
In some embodiments, the acceptor compound is selected from the group consisting of the structures of the following ACCEPTOR LIST 1:
In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments, the acceptor compound comprises a fused ring system having at least five to fifteen 5-membered and/or 6-membered aromatic rings. In some embodiments, the acceptor compound has a first group and a second group with the first group not overlapping with the second group; wherein at least 80% of the singlet excited state population of the lowest singlet excitation state are localized in the first group; and wherein at least 80%, 85%, 90%, or 95% of the triplet excited state population of the lowest triplet excitation state are localized in the second group.
In some embodiments, the emissive region further comprises a first host. In some embodiments, the sensitizer compound forms an exciplex with the first host in the OLED at room temperature. In some embodiments, the first host has a LUMO energy that is lower than the LUMO energies of the sensitizer compound and the acceptor compound in the emissive region. In some embodiments, the first host has a HOMO energy that is lower than the HOMO energies of the sensitizer compound and the acceptor compound in the emissive region. In some embodiments, the first host has a HOMO energy that is higher than the HOMO energies of the sensitizer compound and the acceptor compound in the emissive region. In some embodiments, the first host has a HOMO energy that is higher than the HOMO energy of at least one of the sensitizer compound and the acceptor compound in the emissive region.
In some embodiments, the emissive region further comprises a second host. In some embodiments, the first host forms an exciplex with the second host in the OLED at room temperature. In some embodiments, the concentrations of the first and second hosts in the layer or layers containing the first and second host are greater than the concentrations of the sensitizer compound and the acceptor compound in the layer or layers containing the sensitizer compound and the acceptor compound. In some embodiments, the concentrations of the first and second hosts in the layer or layers containing the first and second host are greater than the concentrations of the acceptor compound in the layer or layers containing the sensitizer compound and the acceptor compound.
In some embodiments, the Si energy of the first host is greater than that of the acceptor compound. In some embodiments, T1 energy of the first host is greater than that of the sensitizer compound. In some embodiments, the sensitizer compound has a HOMO energy that is greater than that of the acceptor compound. In some embodiments, the second host has a HOMO level that is shallower than that of the acceptor compound. In some embodiments, the HOMO level of the acceptor compound is deeper than at least one selected from the sensitizer compound and the first host.
In some embodiments, the first host and/or the second host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, 5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, triazine, boryl, silyl, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, and aza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).
In some embodiments, each of the first host and/or the second host is independently selected from the group consisting of the structures of host group 1 as defined herein. In yet another aspect, the OLED of the present disclosure may also comprise an emissive region containing a formulation of the compounds as disclosed in the present disclosure. In some embodiments, the emissive region consists of one or more organic layers, wherein at least one of the one or more organic layers has a minimum thickness selected from the group consisting of 350, 400, 450, 500, 550, 600, 650 and 700 Å. In some embodiments, the at least one of the one or more organic layers are formed from an Emissive System that has a figure of merit (FOM) value equal to or larger than the number selected from the group consisting of 2.50, 2.55, 2.60, 2.65, 2.70, 2.75, 2.80, 2.85, 2.90, 2.95, 3.00, 5.00, 10.0, 15.0, and 20.0. The definition of FOM is available in U.S. patent Application Publication No. 2023/0292605, and its entire contents are incorporated herein by reference. In some embodiments, the at least one of the one or more organic layers comprises a compound or a formulation of the compound as disclosed in Sections A and D of the present disclosure.
In some embodiments, the OLED or the emissive region comprising an inventive composition disclosed herein can be incorporated into a full-color pixel arrangement of a device. The full-color pixel arrangement of such device comprises at least one pixel, wherein the at least one pixel comprises a first subpixel and a second subpixel. The first subpixel includes a first OLED comprising a first emissive region. The second subpixel includes a second OLED comprising a second emissive region. In some embodiments, the first and/or second OLED, the first and/or second emissive region can be the same or different and each can independently have the various device characteristics and the various embodiments of the inventive compounds included therein, and various combinations and subcombinations of the various device characteristics and the various embodiments of the inventive compounds included therein, as disclosed herein.
In some embodiments, the first emissive region is configured to emit a light having a peak wavelength λmax1; the second emissive region is configured to emit a light having a peak wavelength λmax2. In some embodiments, the difference between the peak wavelengths λmax1 and λmax2 is at least 4 nm but within the same color. For example, a light blue and a deep blue light as described above. In some embodiments, a first emissive region is configured to emit a light having a peak wavelength λmax1 in one region of the visible spectrum of 400-500 nm, 500-600 nm, 600-700 nm; and a second emissive region is configured to emit light having a peak wavelength λmax2 in one of the remaining regions of the visible spectrum of 400-500 nm, 500-600 nm, 600-700 nm. In some embodiments, the first emissive region comprises a first number of emissive layers that are deposited one over the other if more than one; and the second emissive region comprises a second number of emissive layers that is deposited one over the other if more than one; and the first number is different from the second number. In some embodiments, both the first emissive region and the second emissive region comprise a phosphorescent material, which may be the same or different. In some embodiments, the first emissive region comprises a phosphorescent material, while the second emissive region comprises a fluorescent material. In some embodiments, both the first emissive region and the second emissive region comprise a fluorescent material, which may be the same or different.
In some embodiments, the at least one pixel of the OLED or emissive regions includes a total of N subpixels; wherein the N subpixels comprises the first subpixel and the second subpixel; wherein each of the N subpixels comprises an emissive region; wherein the total number of the emissive regions within the at least one pixel is equal to or less than N−1. In some embodiments, the second emissive region is exactly the same as the first emissive region; and each subpixel of the at least one pixel comprises the same one emissive region as the first emissive region. In some embodiments, the full-color pixel arrangements can have a plurality of pixels comprising a first pixel region and a second pixel region; wherein at least one display characteristic in the first pixel region is different from the corresponding display characteristic of the second pixel region, and wherein the at least one display characteristic is selected from the group consisting of resolution, cavity mode, color, outcoupling, and color filter.
In some embodiments, the OLED is a stacked OLED comprising one or more charge generation layers (CGLs). In some embodiments, the OLED comprises a first electrode, a first emissive region disposed over the first electrode, a first CGL disposed over the first emissive region, a second emissive region disposed over the first CGL, and a second electrode disposed over the second emissive region. In some embodiments, the first and/or the second emissive regions can have the various device characteristics as described above for the pixelated device. In some embodiments, the stacked OLED is configured to emit white color. In some embodiments, one or more of the emissive regions in a pixelated or in a stacked OLED comprises a sensitizer and an acceptor with the various sensitizing device characteristics and the various embodiments of the inventive compounds disclosed herein. For example, the first emissive region is comprised in a sensitizing device, while the second emissive region is not comprised in a sensitizing device; in some instances, both the first and the second emissive regions are comprised in sensitizing devices.
In some embodiments, the OLED can emit light having at least 1%, 5%, 10, 30%, 50%, 70%, 80%, 90%, 95%, 99%, or 100% from the plasmonic mode. In some embodiments, at least one of the anode, the cathode, or a new layer disposed over the organic emissive layer functions as an enhancement layer. The enhancement layer comprises a plasmonic material exhibiting surface plasmon resonance that non-radiatively couples to the emitter material and transfers excited state energy from the emitter material to non-radiative mode of surface plasmon polariton. In some embodiments, the enhancement layer is provided no more than a threshold distance away from the organic emissive layer, wherein the emitter material has a total non-radiative decay rate constant and a total radiative decay rate constant due to the presence of the enhancement layer. A threshold distance is where the total non-radiative decay rate constant is equal to the total radiative decay rate constant. Another threshold distance is the distance at which the total radiative decay rate constant divided by the sum of the total non-radiative decay rate constant and total radiative decay rate constant is equal to the photoluminescent yield of the emissive material without the enhancement layer present.
To reduce the amount of Dexter energy transfer between the sensitizer compound and the acceptor compound, it would be preferable to have a large distance between the center of mass of the sensitizer compound and the center of mass of the closest neighboring acceptor compound in the emissive region. Therefore, in some embodiments, the distance between the center of mass of the acceptor compound and the center of mass of the sensitizer compound is at least 2, 1.5, 1.0, or 0.75 nm.
Preferred acceptor/sensitizer VDR combination (A): In some embodiments, it is preferable for the VDR of the acceptor to be less than 0.33 in order to reduce the coupling of the transition dipole moment of the emitting acceptor to the plasmon modes, compared to an isotropic emitter, in order to achieve a higher outcoupling efficiency. In some cases, when the VDR of the acceptor is less than 0.33, it would be preferable for the VDR of the sensitizer to be less than 0.33 in order to improve the coupling of the transition dipole moments of the sensitizer and acceptor to optimize the Forster energy transfer rate. Accordingly, in some embodiments of the inventive OLED, the acceptor compound in the inventive OLED exhibits a VDR value equal to or less than 0.33, 0.30, 0.25, 0.2, 0.15, 0.10, 0.08, or 0.05 when the VDR is measured with an emissive thin film test sample that has the acceptor compound as the only emitter; and the sensitizer compound in the inventive OLED exhibits a VDR value equal to or less than 0.33, 0.30, 0.25, 0.2, 0.15, 0.10, 0.08, or 0.05 when the VDR is measured with an emissive thin film test sample that has the sensitizer compound as the only emitter.
Preferred acceptor/sensitizer VDR combination (B): In some embodiments, it is preferable for the VDR of the acceptor to be less than 0.33 in order to reduce the coupling of the transition dipole moment of the emitting acceptor to the plasmon modes compared to an isotropic emitter in order to achieve a higher outcoupling efficiency. In some cases, when the VDR of the acceptor is less than 0.33, it would be preferable to minimize the intermolecular interactions between the sensitizer and acceptor to decrease the degree of Dexter quenching. By changing the molecular geometry of the sensitizer to reduce the intermolecular interactions, it may be preferable to have a sensitizer with a VDR greater than 0.33. Accordingly, in some embodiments of the inventive OLED, the acceptor compound in the inventive OLED exhibits a VDR value equal to or less than 0.33, 0.30, 0.25, 0.2, 0.15, 0.10, 0.08, or 0.05 when the VDR is measured with an emissive thin film test sample that has the acceptor compound as the only emitter; and the sensitizer compound in the inventive OLED exhibits a VDR value larger than 0.33, 0.4, 0.5, 0.6, or 0.7 when the VDR is measured with an emissive thin film test sample that has the sensitizer compound as the only emitter.
Preferred acceptor/sensitizer VDR combination (C): In some embodiments, it is preferable for the VDR of the acceptor to be greater than 0.33 in order to increase the coupling of the transition dipole moment of the acceptor to the plasmon modes compared to an isotropic emitter in order to decrease the transient lifetime of the excited states in the emissive layer. In some cases, the increased coupling to the plasmon modes can be paired with an enhancement layer in a plasmonic OLED device to improve efficiency and extend operational lifetime. In some cases, when the VDR of the acceptor is greater than 0.33, it would be preferable to minimize the intermolecular interactions between the senstizer and acceptor to decrease the degree of Dexter quenching. By changing the molecular geometry of the sensitizer to reduce the intermolecular interactions, it may be preferable to have a sensitizer with a VDR less than 0.33. Accordingly, in some embodiments of the inventive OLED, the acceptor compound in the inventive OLED exhibits a VDR value larger than 0.33, 0.4, 0.5, 0.6, or 0.7 when the VDR is measured with an emissive thin film test sample that has the acceptor compound as the only emitter; and the sensitizer compound in the inventive OLED exhibits a VDR value equal to or less than 0.33, 0.30, 0.25, 0.2, 0.15, 0.10, 0.08, or 0.05 when the VDR is measured with an emissive thin film test sample that has the sensitizer compound as the only emitter.
Preferred acceptor/sensitizer VDR combination (D): In some embodiments, it is preferable for the VDR of the acceptor to be greater than 0.33 in order to increase the coupling of the transition dipole moment of the acceptor to the plasmon modes compared to an isotropic emitter in order to decrease the transient lifetime of the excited states in the emissive layer. In some cases, the increased coupling to the plasmon modes can be paired with an enhancement layer in a plasmonic OLED device to improve efficiency and extend operational lifetime. In some cases, when the VDR of the acceptor is greater than 0.33, it would be preferable for the VDR of the sensitizer to be greater than 0.33 in order to improve the coupling of the transition dipole moments of the sensitizer and acceptor to optimize the Forster energy transfer rate. Accordingly, in some embodiments of the inventive OLED, the acceptor compound in the inventive OLED exhibits a VDR value larger than 0.33, 0.4, 0.5, 0.6, or 0.7 when the VDR is measured with an emissive thin film test sample that has the acceptor compound as the only emitter; and the sensitizer compound in the inventive OLED exhibits a VDR value larger than 0.33, 0.4, 0.5, 0.6, or 0.7 when the VDR is measured with an emissive thin film test sample that has the sensitizer compound as the only emitter.
VDR is the ensemble average fraction of vertically oriented molecular dipoles of the light-emitting compound in a thin film sample of an emissive layer, where the orientation “vertical” is relative to the plane of the surface of the substrate (i.e., normal to the surface of the substrate plane) on which the thin film sample is formed. A similar concept is horizontal dipole ratio (HDR) which is the ensemble average fraction of horizontally oriented molecular dipoles of the light-emitting compound in a thin film sample of an emissive layer, where the orientation “horizontal” is relative to the plane of the surface of the substrate (i.e. parallel to the surface of the substrate plane) on which the thin film sample is formed. By definition, VDR+HDR=1. VDR can be measured by angle dependent, polarization dependent, photoluminescence measurements. By comparing the measured emission pattern of a photo-excited thin film test sample, as a function of polarization, to the computationally modeled pattern, one can determine VDR of the thin film test sample emission layer. For example, a modelled data of p-polarized emission is shown in
To measure VDR values of the thin film test samples, a thin film test sample can be formed with the acceptor compound or the sensitizer compound (depending on whether the VDR of the acceptor compound or the sensitizer compound is being measured) as the only emitter in the thin film and a Reference Host Compound A as the host. Preferably, the Reference Host Compound A is
The thin film test sample is formed by thermally evaporating the emitter compound and the host compound on a substrate. For example, the emitter compound and the host compound can be co-evaporated. In some embodiments, the doping level of the emitter compounds in the host can be from 0.1 wt. % to 50 wt. %. In some embodiments, the doping level of the emitter compounds in the host can be from 3 wt. % to 20 wt. % for blue emitters. In some embodiments, the doping level of the emitter compounds in the host can be from 1 wt. % to 15 wt. % for red and green emitters. The thickness of the thermally evaporated thin film test sample can have a thickness of from 50 to 1000 Å.
In some embodiments, the OLED of the present disclosure can comprise a sensitizer, an acceptor, and one or more hosts in the emissive region, and the preferred acceptor/sensitizer VDR combinations (A)-(D) mentioned above are still applicable. In these embodiments, the VDR values for the acceptor compound can be measured with a thin film test sample formed of the one or more hosts and the acceptor, where the acceptor is the only emitter in the thin film test sample. Similarly, the VDR values for the sensitizer compound can be measured with a thin film test sample formed of the one or more hosts and the sensitizer, where the sensitizer is the only emitter in the thin film test sample.
In the example used to generate
Because the VDR represents the average dipole orientation of the light-emitting compound in the thin film sample, even if there are additional emission capable compounds in the emissive layer, if they are not contributing to the light emission, the VDR measurement does not reflect their VDR. Further, by inclusion of a host material that interacts with the light-emitting compound, the VDR of the light-emitting compound can be modified. Thus, a light-emitting compound in a thin film sample with host material A will exhibit one measured VDR value and that same light-emitting compound in a thin film sample with host material B will exhibit a different measured VDR value. Further, in some embodiments, exciplex or excimers are desirable which form emissive states between two neighboring molecules. These emissive states may have a VDR that is different than that if only one of the components of the exciplex or excimer were emitting or present in the sample.
In some embodiments, the OLED is a plasmonic OLED. In some embodiments, the OLED is a wave-guided OLED.
In some embodiments, the emissive region can further include a second host. In some embodiments, the second host comprises a moiety selected from the group consisting of bicarbazole, indolocarbazole, triazine, pyrimidine, pyridine, and boryl. In some embodiments, the second host has a HOMO level that is shallower than that of the acceptor compound.
In some embodiments, the OLED emits a white light at room temperature when a voltage is applied across the device.
In some embodiments, the OLED emits a luminescent radiation at room temperature when a voltage is applied across the device; wherein the luminescent first radiation component contributed from the acceptor compound with an emission λmax1 being independently selected from the group consisting of larger than 340 nm to equal or less than 500 nm, larger than 500 nm to equal or less than 600 nm, and larger than 600 nm to equal or less than 900 nm. In some embodiments, the first radiation component has FWHM of 50, 40, 35, 30, 25, 20, 15, 10, or 5 nm or less. In some embodiments, the first radiation component has a 10% onset of the emission peak is less than 465, 460, 455, or 450 nm.
In some embodiments, the sensitizer compound is partially or fully deuterated. In some embodiments, the acceptor compound is partially or fully deuterated. In some embodiments, the first host is partially or fully deuterated. In some embodiments, the second host is partially or fully deuterated.
In some embodiments, compound S1 and/or compound A1 each independently comprises at least one substituent having a spherocity greater than or equal to 0.45, 0.55, 0.65, 0.75, or 0.80. The spherocity is a measurement of the three-dimensionality of bulky groups. Spherocity is defined as the ratio between the principal moments of inertia (PMI). Specifically, spherocity is the ratio of three times PMI1 over the sum of PMI1, PMI2, and PMI3, where PMI1 is the smallest principal moment of inertia, PMI2 is the second smallest principal moment of inertia, and PMI3 is the largest principal moment of inertia. The spherocity of the lowest energy conformer of a structure after optimization of the ground state with density functional theory may be calculated. More detailed information can be found in paragraphs [0054] to [0059] of U.S. application Ser. No. 18/062,110 filed Dec. 6, 2022, the contents of which are incorporated herein by reference. In some embodiments, compound S1 and/or compound A1 each independently comprises at least one substituent having a Van der Waals volume greater than 153, 206, 259, 290, or 329 Å3. In some embodiments, compound S1 and/or compound A1 each independently comprises at least one substituent having a molecular weight greater than 167, 187, 259, 303, or 305 amu.
In some embodiments, one of the first and second hosts is a hole transporting host, the other one of the first and second host is an electron transporting host. In some embodiments, the first host is a hole transporting host; and wherein the first host comprises at least one chemical group selected from the group consisting of amino, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, and 5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole. In some embodiments, the first host is an electron transporting host; and wherein the first host comprises at least one chemical group selected from the group consisting of pyridine, pyrimidine, pyrazine, pyridazine, triazine, imidazole, aza-triphenylene, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, boryl, aza-5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, and aza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene). In some embodiments, one of the first and second hosts is a bipolar host comprising both hole transporting and electron transporting moieties.
In some embodiments, the OLED further comprises a color conversion layer or a color filter.
In some embodiments, a formulation can comprise at least two different compounds of the following compounds: a sensitizer compound, an acceptor compound and a host.
In some embodiments, a chemical structure selected from the group consisting of a monomer, a polymer, a macromolecule, and a supramolecule, wherein the chemical structure comprises at least two of the following components: a sensitizer compound, an acceptor compound and a host.
In some embodiments, a premixed co-evaporation source is disclosed that is a mixture that at least comprises a first compound and a second compound; wherein the co-evaporation source is a co-evaporation source for vacuum deposition process or OVJP process; wherein the first compound and the second compound are differently selected from the group 1 consisting of: a sensitizer compound, an acceptor compound, a first host compound; and a second host compound; wherein the first compound has an evaporation temperature T1 of 150 to 350° C.; wherein the second compound has an evaporation temperature T2 of 150 to 350° C.; wherein absolute value of T1-T2 is less than 20° C.; wherein the first compound has a concentration C1 in said mixture and a concentration C2 in a test film formed by evaporating the mixture in a vacuum deposition tool at a constant pressure between 1×10−6 Torr to 1×10−9 Torr, at a 2 Å/sec deposition rate on a surface positioned at a predefined distance away from the mixture being evaporated; and wherein the absolute value of (C1−C2)/C1 is less than 5%. In some embodiments, the mixture further comprises a third compound; wherein the third compound is different from the first and the second compound, and is selected from the same group 1; wherein the third compound has an evaporation temperature T3 of 150 to 350° C., and wherein absolute value of T1−T3 is less than 20° C.
In some embodiments, the first compound has evaporation temperature T1 of 200 to 350° C. and the second compound has evaporation temperature T2 of 200 to 350° C. In some embodiments, the absolute value of (C1−C2)/C1 is less than 3%. In some embodiments, the first compound has a vapor pressure of P1 at T1 at 1 atm, and the second compound has a vapor pressure of P2 at T2 at 1 atm; and wherein the ratio of P1/P2 is within the range of 0.90:1 to 1.10:1. In some embodiments, the first compound has a first mass loss rate and the second compound has a second mass loss rate, wherein the ratio between the first mass loss rate and the second mass loss rate is within the range of 0.90:1 to 1.10:1, 0.95:1 to 1.05:1, or 0.97:1 to 1.03:1. In some embodiments, the first compound and the second compound each has a purity in excess of 99% as determined by high pressure liquid chromatography. In some embodiments, the composition is in liquid form at a temperature less than the lesser of T1 and T2.
In some embodiments, a method for fabricating an organic light emitting device can comprises: providing a substrate having a first electrode disposed thereon; depositing a first organic layer over the first electrode by evaporating a pre-mixed co-evaporation source that is a mixture of a first compound and a second compound described above in a high vacuum deposition tool with a chamber base pressure between 1×10−6 Torr to 1×10−9 Torr; and depositing a second electrode over the first organic layer.
It should be understood that embodiments of all the compounds and devices described herein may be interchangeable if those embodiments are also applicable under different aspects of the entire disclosure.
In some embodiments, each of the first compound, the second compound, the sensitizer compound, the acceptor compound, the host compound, described herein can be at least 10% deuterated, at least 20% deuterated, at least 30% deuterated, at least 40% deuterated, at least 50% deuterated, at least 60% deuterated, at least 70% deuterated, at least 80% deuterated, at least 90% deuterated, at least 95% deuterated, at least 99% deuterated, or 100% deuterated. As used herein, percent deuteration has its ordinary meaning and includes the percent of possible hydrogen atoms (e.g., positions that are hydrogen or deuterium) that are replaced by deuterium atoms.
In yet another aspect, the OLED of the present disclosure may also comprise an emissive region containing a compound as disclosed herein.
In some embodiments, the emissive region can comprise a compound as described herein.
In some embodiments, at least one of the anode, the cathode, or a new layer disposed over the organic emissive layer functions as an enhancement layer. The enhancement layer comprises a plasmonic material exhibiting surface plasmon resonance that non-radiatively couples to the emitter material and transfers excited state energy from the emitter material to non-radiative mode of surface plasmon polariton. The enhancement layer is provided no more than a threshold distance away from the organic emissive layer, wherein the emitter material has a total non-radiative decay rate constant and a total radiative decay rate constant due to the presence of the enhancement layer and the threshold distance is where the total non-radiative decay rate constant is equal to the total radiative decay rate constant. In some embodiments, the OLED further comprises an outcoupling layer. In some embodiments, the outcoupling layer is disposed over the enhancement layer on the opposite side of the organic emissive layer. In some embodiments, the outcoupling layer is disposed on opposite side of the emissive layer from the enhancement layer but still outcouples energy from the surface plasmon mode of the enhancement layer. The outcoupling layer scatters the energy from the surface plasmon polaritons. In some embodiments this energy is scattered as photons to free space. In other embodiments, the energy is scattered from the surface plasmon mode into other modes of the device such as but not limited to the organic waveguide mode, the substrate mode, or another waveguiding mode. If energy is scattered to the non-free space mode of the OLED other outcoupling schemes could be incorporated to extract that energy to free space. In some embodiments, one or more intervening layer can be disposed between the enhancement layer and the outcoupling layer. The examples for intervening layer(s) can be dielectric materials, including organic, inorganic, perovskites, oxides, and may include stacks and/or mixtures of these materials.
The enhancement layer modifies the effective properties of the medium in which the emitter material resides resulting in any or all of the following: a decreased rate of emission, a modification of emission line-shape, a change in emission intensity with angle, a change in the stability of the emitter material, a change in the efficiency of the OLED, and reduced efficiency roll-off of the OLED device. Placement of the enhancement layer on the cathode side, anode side, or on both sides results in OLED devices which take advantage of any of the above-mentioned effects. In addition to the specific functional layers mentioned herein and illustrated in the various OLED examples shown in the figures, the OLEDs according to the present disclosure may include any of the other functional layers often found in OLEDs.
The enhancement layer can be comprised of plasmonic materials, optically active metamaterials, or hyperbolic metamaterials. As used herein, a plasmonic material is a material in which the real part of the dielectric constant crosses zero in the visible or ultraviolet region of the electromagnetic spectrum. In some embodiments, the plasmonic material includes at least one metal. In such embodiments the metal may include at least one of Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca alloys or mixtures of these materials, and stacks of these materials. In general, a metamaterial is a medium composed of different materials where the medium as a whole acts differently than the sum of its material parts. In particular, we define optically active metamaterials as materials which have both negative permittivity and negative permeability. Hyperbolic metamaterials, on the other hand, are anisotropic media in which the permittivity or permeability are of different sign for different spatial directions. Optically active metamaterials and hyperbolic metamaterials are strictly distinguished from many other photonic structures such as Distributed Bragg Reflectors (“DBRs”) in that the medium should appear uniform in the direction of propagation on the length scale of the wavelength of light. Using terminology that one skilled in the art can understand: the dielectric constant of the metamaterials in the direction of propagation can be described with the effective medium approximation. Plasmonic materials and metamaterials provide methods for controlling the propagation of light that can enhance OLED performance in a number of ways.
In some embodiments, the enhancement layer is provided as a planar layer. In other embodiments, the enhancement layer has wavelength-sized features that are arranged periodically, quasi-periodically, or randomly, or sub-wavelength-sized features that are arranged periodically, quasi-periodically, or randomly. In some embodiments, the wavelength-sized features and the sub-wavelength-sized features have sharp edges.
In some embodiments, the outcoupling layer has wavelength-sized features that are arranged periodically, quasi-periodically, or randomly, or sub-wavelength-sized features that are arranged periodically, quasi-periodically, or randomly. In some embodiments, the outcoupling layer may be composed of a plurality of nanoparticles and in other embodiments the outcoupling layer is composed of a plurality of nanoparticles disposed over a material. In these embodiments the outcoupling may be tunable by at least one of varying a size of the plurality of nanoparticles, varying a shape of the plurality of nanoparticles, changing a material of the plurality of nanoparticles, adjusting a thickness of the material, changing the refractive index of the material or an additional layer disposed on the plurality of nanoparticles, varying a thickness of the enhancement layer, and/or varying the material of the enhancement layer. The plurality of nanoparticles of the device may be formed from at least one of metal, dielectric material, semiconductor materials, an alloy of metal, a mixture of dielectric materials, a stack or layering of one or more materials, and/or a core of one type of material and that is coated with a shell of a different type of material. In some embodiments, the outcoupling layer is composed of at least metal nanoparticles wherein the metal is selected from the group consisting of Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, alloys or mixtures of these materials, and stacks of these materials. The plurality of nanoparticles may have additional layer disposed over them. In some embodiments, the polarization of the emission can be tuned using the outcoupling layer. Varying the dimensionality and periodicity of the outcoupling layer can select a type of polarization that is preferentially outcoupled to air. In some embodiments the outcoupling layer also acts as an electrode of the device.
In yet another aspect, the present disclosure also provides a consumer product comprising an organic light-emitting device (OLED) as described herein.
In some embodiments, the consumer product can be one of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cell phone, tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, a light therapy device, and a sign.
Generally, an OLED comprises at least one organic layer disposed between and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer(s). The injected holes and electrons each migrate toward the oppositely charged electrode. When an electron and hole localize on the same molecule, an “exciton,” which is a localized electron-hole pair having an excited energy state, is formed. Light is emitted when the exciton relaxes via a photoemissive mechanism. In some cases, the exciton may be localized on an excimer or an exciplex. Non-radiative mechanisms, such as thermal relaxation, may also occur, but are generally considered undesirable.
Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.
The initial OLEDs used emissive molecules that emitted light from their singlet states (“fluorescence”) as disclosed, for example, in U.S. Pat. No. 4,769,292, which is incorporated by reference in its entirety. Fluorescent emission generally occurs in a time frame of less than 10 nanoseconds.
More recently, OLEDs having emissive materials that emit light from triplet states (“phosphorescence”) have been demonstrated. Baldo et al., “Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices,” Nature, vol. 395, 151-154, 1998; (“Baldo-I”) and Baldo et al., “Very high-efficiency green organic light-emitting devices based on electrophosphorescence,” Appl. Phys. Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), are incorporated by reference in their entireties. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporated by reference.
More examples for each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Pat. No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003/0230980, which is incorporated by reference in its entirety. Examples of emissive and host materials are disclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which is incorporated by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. Patent Application Publication No. 2003/0230980, which is incorporated by reference in its entirety. U.S. Pat. Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entireties, disclose examples of cathodes including compound cathodes having a thin layer of metal such as Mg:Ag with an overlying transparent, electrically-conductive, sputter-deposited ITO layer. The theory and use of blocking layers is described in more detail in U.S. Pat. No. 6,097,147 and U.S. Patent Application Publication No. 2003/0230980, which are incorporated by reference in their entireties. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004/0174116, which is incorporated by reference in its entirety. A description of protective layers may be found in U.S. Patent Application Publication No. 2004/0174116, which is incorporated by reference in its entirety.
The simple layered structure illustrated in
Structures and materials not specifically described may also be used, such as OLEDs comprised of polymeric materials (PLEDs) such as disclosed in U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated by reference in its entirety. By way of further example, OLEDs having a single organic layer may be used. OLEDs may be stacked, for example as described in U.S. Pat. No. 5,707,745 to Forrest et al, which is incorporated by reference in its entirety. The OLED structure may deviate from the simple layered structure illustrated in
Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties, organic vapor phase deposition (OVPD), such as described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety, and deposition by organic vapor jet printing (OVJP), such as described in U.S. Pat. No. 7,431,968, which is incorporated by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, and patterning associated with some of the deposition methods such as ink-jet and organic vapor jet printing (OVJP). Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having 20 carbons or more may be used, and 3-20 carbons are a preferred range. Materials with asymmetric structures may have better solution processability than those having symmetric structures, because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.
Devices fabricated in accordance with embodiments of the present disclosure may further optionally comprise a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment including moisture, vapor and/or gases, etc. The barrier layer may be deposited over, under or next to a substrate, an electrode, or over any other parts of a device including an edge. The barrier layer may comprise a single layer, or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include compositions having a single phase as well as compositions having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate an inorganic or an organic compound or both. The preferred barrier layer comprises a mixture of a polymeric material and a non-polymeric material as described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos. PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporated by reference in their entireties. To be considered a “mixture”, the aforesaid polymeric and non-polymeric materials comprising the barrier layer should be deposited under the same reaction conditions and/or at the same time. The weight ratio of polymeric to non-polymeric material may be in the range of 95:5 to 5:95. The polymeric material and the non-polymeric material may be created from the same precursor material. In one example, the mixture of a polymeric material and a non-polymeric material consists essentially of polymeric silicon and inorganic silicon.
Devices fabricated in accordance with embodiments of the present disclosure can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into a variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include display screens, lighting devices such as discrete light source devices or lighting panels, etc. that can be utilized by the end-user product manufacturers. Such electronic component modules can optionally include the driving electronics and/or power source(s). Devices fabricated in accordance with embodiments of the present disclosure can be incorporated into a wide variety of consumer products that have one or more of the electronic component modules (or units) incorporated therein. A consumer product comprising an OLED that includes the compound of the present disclosure in the organic layer in the OLED is disclosed. Such consumer products would include any kind of products that include one or more light source(s) and/or one or more of some type of visual displays. Some examples of such consumer products include flat panel displays, curved displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully or partially transparent displays, flexible displays, rollable displays, foldable displays, stretchable displays, laser printers, telephones, mobile phones, tablets, phablets, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, camcorders, viewfinders, micro-displays (displays that are less than 2 inches diagonal), 3-D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screen, a light therapy device, and a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present disclosure, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as 18 degrees C. to 30 degrees C., and more preferably at room temperature (20-25° C.), but could be used outside this temperature range, for example, from −40 degree C. to +80° C.
More details on OLEDs, and the definitions described above, can be found in U.S. Pat. No. 7,279,704, which is incorporated herein by reference in its entirety.
The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may employ the materials and structures. More generally, organic devices, such as organic transistors, may employ the materials and structures.
In some embodiments, the OLED has one or more characteristics selected from the group consisting of being flexible, being rollable, being foldable, being stretchable, and being curved. In some embodiments, the OLED is transparent or semi-transparent. In some embodiments, the OLED further comprises a layer comprising carbon nanotubes.
In some embodiments, the OLED further comprises a layer comprising a delayed fluorescent emitter. In some embodiments, the OLED comprises a RGB pixel arrangement or white plus color filter pixel arrangement. In some embodiments, the OLED is a mobile device, a hand held device, or a wearable device. In some embodiments, the OLED is a display panel having less than 10 inch diagonal or 50 square inch area. In some embodiments, the OLED is a display panel having at least 10 inch diagonal or 50 square inch area. In some embodiments, the OLED is a lighting panel.
The organic light emitting device of the present disclosure may be used in combination with a wide variety of other materials. For example, it may be used in conjunction with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes and other layers that may be present. The materials described or referred to below are non-limiting examples of materials that may be useful in combination with the device disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that may be useful in combination.
A charge transport layer can be doped with conductivity dopants to substantially alter its density of charge carriers, which will in turn alter its conductivity. The conductivity is increased by generating charge carriers in the matrix material, and depending on the type of dopant, a change in the Fermi level of the semiconductor may also be achieved. Hole-transporting layer can be doped by p-type conductivity dopants and n-type conductivity dopants are used in the electron-transporting layer. In some embodiments, conductivity dopants comprise at least one chemical moiety selected from the group consisting of cyano, fluorinated aryl or heteroaryl, fluorinated alkyl or cycloalkyl, alkylene, heteroaryl, amide, benzodithiophene, and highly conjugated heteroaryl groups extended by non-ring double bonds.
A hole injecting/transporting material to be used in the present disclosure is not particularly limited, and any compound may be used as long as the compound is typically used as a hole injecting/transporting material. Examples of the material include, but are not limited to: a phthalocyanine or porphyrin derivative; an aromatic amine derivative; an indolocarbazole derivative; a polymer containing fluorohydrocarbon; a polymer with conductivity dopants; a conducting polymer, such as PEDOT/PSS; a self-assembly monomer derived from compounds such as phosphonic acid and silane derivatives; a metal oxide derivative, such as MoOx; a p-type semiconducting organic compound, such as 1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and a cross-linkable compounds.
Examples of aromatic amine derivatives used in HIL or HTL include, but not limit to the following general structures:
Each of Ar1 to Ar9 is selected from the group consisting of aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene; the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine; and the group consisting of 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Each of Ar1 to Ar9 may be unsubstituted or may be substituted by a general substituent as described above, any two substituents can be joined or fused into a ring.
In some embodiments, each Ar1 to Ar9 independently comprises a moiety selected from the group consisting of:
wherein k is an integer from 1 to 20; X101 to X108 is C or N; Z101 is C, N, O, or S.
Examples of metal complexes used in HIL or HTL include, but are not limited to the following general formula:
wherein Met is a metal, which can have an atomic weight greater than 40; (Y101-Y102) is a bidentate ligand, the coordinating atoms of Y101 and Y102 are independently selected from C, N, O, P, and S; L101 is an another ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal; and k′+k″ is the maximum number of ligands that may be attached to the metal.
In some embodiments, (Y101-Y102) is a 2-phenylpyridine or 2-phenylimidazole derivative. In some embodiments, (Y101-Y102) is a carbene ligand. In some embodiments, Met is selected from Ir, Pt, Pd, Os, Cu, and Zn. In some embodiments, the metal complex has a smallest oxidation potential in solution vs. Fc+/Fc couple less than about 0.6 V.
In some embodiments, the HIL/HTL material is selected from the group consisting of phthalocyanine and porphryin compounds, starburst triarylamines, CFx fluorohydrocarbon polymer, conducting polymers (e.g., PEDOT:PSS, polyaniline, polypthiophene), phosphonic acid and sliane SAMs, triarylamine or polythiophene polymers with conductivity dopants, Organic compounds with conductive inorganic compounds (such as molybdenum and tungsten oxides), n-type semiconducting organic complexes, metal organometallic complexes, cross-linkable compounds, polythiophene based polymers and copolymers, triarylamines, triaylamine with spirofluorene core, arylamine carbazole compounds, triarylamine with (di)benzothiophene/(di)benzofuran, indolocarbazoles, isoindole compounds, and metal carbene complexes.
An electron blocking layer (EBL) may be used to reduce the number of electrons and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies, and/or longer lifetime, as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and/or higher triplet energy than one or more emitters closest to the EBL interface. In some embodiments, the compound used in EBL contains at least one carbazole group and/or at least one arylamine group. In some embodiments the HOMO level of the compound used in the EBL is shallower than the HOMO level of one or more of the hosts in the EML. In some embodiments, the compound used in EBL contains the same molecule or the same functional groups used as one of the hosts described herein.
The light emitting layer of the organic EL device of the present disclosure preferably contains at least a light emitting material as the dopant, and a host material. Examples of the host material are not particularly limited, and any metal complexes or organic compounds may be used as long as the host won't fully quench the emission of the dopant.
Examples of metal complexes used as host are preferred to have the following general formula:
wherein Met is a metal; (Y103-Y104) is a bidentate ligand, the coordinating atoms of Y103 and Y104 are independently selected from C, N, O, P, and S; L110 is an another ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal; and k′+k″ is the maximum number of ligands that may be attached to the metal.
In some embodiments, the metal complexes are:
wherein (O—N) is a bidentate ligand, having metal coordinated to atoms O and N.
In some embodiments, Met is selected from Ir and Pt. In a further embodiment, (Y103-Y104) is a carbene ligand.
In some embodiments, the host compound contains at least one of the following groups selected from the group consisting of aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene; the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-carbazole, aza-indolocarbazole, aza-triphenylene, aza-tetraphenylene, 5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene; and the group consisting of 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Each option within each group may be unsubstituted or may be substituted by the general substituents as described herein or may be further fused.
In some embodiments, the host compound comprises at least one of the moieties selected from the group consisting of: k
wherein k is an integer from 0 to 20 or 1 to 20. X101 to X108 are independently selected from C or N. Z101 and Z102 are independently selected from C, N, O, or S.
In some embodiments, the host material is selected from the group consisting of arylcarbazoles, metal 8-hydroxyquinolates, (e.g., alq3, balq), metal phenoxybenzothiazole compounds, conjugated oligomers and polymers (e.g., polyfluorene), aromatic fused rings, zinc complexes, chrysene based compounds, aryltriphenylene compounds, poly-fused heteroaryl compounds, donor acceptor type molecules, dibenzofuran/dibenzothiophene compounds, polymers (e.g., pvk), spirofluorene compounds, spirofluorene-carbazole compounds, indolocabazoles, 5-member ring electron deficient heterocycles (e.g., triazole, oxadiazole), tetraphenylene complexes, metal phenoxypyridine compounds, metal coordination complexes (e.g., Zn, Al with N{circumflex over ( )}N ligands), dibenzothiophene/dibenzofuran-carbazole compounds, silicon/germanium aryl compounds, aryl benzoyl esters, carbazole linked by non-conjugated groups, aza-carbazole/dibenzofuran/dibenzothiophene compounds, and high triplet metal organometallic complexes (e.g., metal-carbene complexes).
One or more emitter materials may be used in conjunction with the compound or device of the present disclosure. The emitter material can be emissive or non-emissive in the current device as described herein. Examples of the emitter materials are not particularly limited, and any compounds may be used as long as the compounds are capable of producing emissions in a regular OLED device. Examples of suitable emitter materials include, but are not limited to, compounds which are capable of producing emissions via phosphorescence, non-delayed fluorescence, delayed fluorescence, especially the thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence), triplet-triplet annihilation, or combinations of these processes.
In some embodiments, the emitter material has the formula of M(L1)x(L2)y(L3)z;
In some embodiments, the emitter material is selected from the group consisting of the structures of LIST E3 and E4 as defined herein.
In some embodiments of the above LIST E3 and LIST E4, each unsubstituted aromatic carbon atom can be replaced with N to form an aza-ring. In some embodiments, the maximum number of N atom in one ring is 1 or 2. In some embodiments of the above Dopant Groups 2, Pt atom in each formula can be replaced by Pd atom.
In some embodiments of the OLED, the delayed fluorescence material comprises at least one donor group and at least one acceptor group. In some embodiments, the delayed fluorescence material is a metal complex. In some embodiments, the delayed fluorescence material is a non-metal complex. In some embodiments, the delayed fluorescence material is a Zn, Cu, Ag, or Au complex.
In some embodiments of the OLED, the delayed fluorescence material has the formula of M(L5)(L6), wherein M is Cu, Ag, or Au, L5 and L6 are different, and L5 and L6 are independently selected from the group consisting of the structures of LIST E5 as defined herein.
In some embodiments of the OLED, the delayed fluorescence material comprises at least one of the donor moieties selected from the group consisting of the structures of LIST E6 as defined herein. In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
In some embodiments, the delayed fluorescence material comprises at least one of the acceptor moieties selected from the group consisting of nitrile, isonitrile, borane, fluoride, pyridine, pyrimidine, pyrazine, triazine, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, aza-triphenylene, imidazole, pyrazole, oxazole, thiazole, isoxazole, isothiazole, triazole, thiadiazole, and oxadiazole. In some embodiments, the acceptor moieties and the donor moieties as described herein can be connected directly, through a conjugated linker, or a non-conjugated linker, such as a sp3 carbon or silicon atom.
In some embodiments, the fluorescent material comprises at least one of the chemical moieties selected from the group consisting of the structures of LIST A1 as defined herein. In some of the above embodiments, any carbon ring atoms up to maximum of a total number of three, together with their substituents, in each phenyl ring of any of above structures can be replaced with N.
A hole blocking layer (HBL) may be used to reduce the number of holes and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies and/or longer lifetime as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED. In some embodiments, the HBL material has a lower HOMO (further away from the vacuum level) and/or higher triplet energy than one or more of the emitters closest to the HBL interface.
In some embodiments, a compound used in the HBL contains the same molecule or the same functional groups used as host described above.
In some embodiments, a compound used in the HBL comprises at least one of the following moieties selected from the group consisting of:
wherein k is an integer from 1 to 20; L101 is another ligand, k′ is an integer from 1 to 3.
Electron transport layer (ETL) may include a material capable of transporting electrons. Electron transport layer may be intrinsic (undoped), or doped. Doping may be used to enhance conductivity. Examples of the ETL material are not particularly limited, and any metal complexes or organic compounds may be used as long as they are typically used to transport electrons.
In some embodiments, compound used in ETL comprises at least one of the following moieties in the molecule:
and fullerenes; wherein k is an integer from 1 to 20, X101 to X108 is selected from C or N; Z101 is selected from the group consisting of C, N, O, and S.
In some embodiments, the metal complexes used in ETL contains, but not limit to the following general formula:
wherein (O—N) or (N—N) is a bidentate ligand, having metal coordinated to atoms O, N or N, N; L101 is another ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal.
In some embodiments, the ETL material is selected from the group consisting of anthracene-benzoimidazole compounds, aza triphenylene derivatives, anthracene-benzothiazole compounds, metal 8-hydroxyquinolates, metal hydroxybenoquinolates, bathocuprine compounds, 5-member ring electron deficient heterocycles (e.g., triazole, oxadiazole, imidazole, benzoimidazole), silole compounds, arylborane compounds, fluorinated aromatic compounds, fullerene (e.g., C60), triazine complexes, and Zn (N{circumflex over ( )}N) complexes.
In tandem or stacked OLEDs, the CGL plays an essential role in the performance, which is composed of an n-doped layer and a p-doped layer for injection of electrons and holes, respectively. Electrons and holes are supplied from the CGL and electrodes. The consumed electrons and holes in the CGL are refilled by the electrons and holes injected from the cathode and anode, respectively; then, the bipolar currents reach a steady state gradually. Typical CGL materials include n and p conductivity dopants used in the transport layers.
In any compounds disclosed herein, the hydrogen atoms can be partially or fully deuterated. The minimum amount of hydrogen of the compound being deuterated is selected from the group consisting of 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, and 100%. As used herein, percent deuteration has its ordinary meaning and includes the percent of all possible hydrogen and deuterium atoms that are replaced by deuterium atoms. In some embodiments, the deuterium atoms are attached to an aromatic ring. In some embodiments, the deuterium atoms are attached to a saturated carbon atom, such as an alkyl or cycloalkyl carbon atom. In some other embodiments, the deuterium atoms are attached to a heteroatom, such as Si, or Ge atom.
It is understood that the various embodiments described herein are by way of example only and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures without deviating from the spirit of the invention. The present invention as claimed may therefore include variations from the particular examples and preferred embodiments described herein, as will be apparent to one of skill in the art. It is understood that various theories as to why the invention works are not intended to be limiting.
OLED devices were fabricated using several host and emitter materials comprising the elements, Si, CN, B, D, and F. The device results are shown in Table 3, where the EQE is taken at 10 mA/cm2 and the lifetime (LT90) is the time to reduction of brightness to 90% of the initial luminance at a constant current density of 20 mA/cm2.
OLEDs were grown on a glass substrate pre-coated with an indium-tin-oxide (ITO) layer having a sheet resistance of 15-Ω/sq. Prior to any organic layer deposition or coating, the substrate was degreased with solvents and then treated with an oxygen plasma for 1.5 minutes with 50 W at 100 mTorr and with UV ozone for minutes. The devices were fabricated in high vacuum (<10−6 Torr) by thermal evaporation. The anode electrode was 750 Å of indium tin oxide (ITO). All devices were encapsulated with a glass lid sealed with an epoxy resin in a nitrogen glove box (<1 ppm of H2 and O2) immediately after fabrication with a moisture getter incorporated inside the package. Doping percentages are in volume percent. The devices were grown in two different device structures.
The devices had organic layers consisting of, sequentially, from the ITO surface, 100 Å of Compound 1 (HIL), 250 Å of Compound 2 (HTL), 50 Å of EBL, 300 Å HHost X % of EHost, Y % of Emitter, 50 Å of HBL, 300 Å of Compound 5 doped wit 35% of Compound 6 (ETL), 10 Å of Compound 5 (EIL) followed by 1,000 Å of Al (Cathode). Wherein the EBL, HHost, EHost, HBL, X, and Y are each shown in Table 1. For each device in Table 1, the elements comprised within each material are shown in Table 2. The corresponding device data are given in Table 3. The EQE, and LT90 for each example are reported relative to the values for the comparison device Comparison 1.
The above data shows that each device Example 1-19 exhibited longer lifetime and/or higher efficiency than the comparison device, Comparison 1. The up to 40% increase in EQEs and the up to 810% longer lifetimes are beyond any value that could be attributed to experimental error and the observed improvement is significant. These substantial enhancements were achieved for optimized devices from a variety of different host and dopant structures, but all retained similar structural features, namely, a similar tetradentate platinum scaffold, an electron deficient comprising electron transporting host, and a 3,9-bicarbazole based hole transporting host. Based on the fact that the devices have similar structures with the primary difference being the incorporation of moieties comprising elements such as Si, CN, D, and B, the significant performance improvement observed in the above data was unexpected. Without being bound by any theories, this improvement may be attributed to the greater structural and energetic variability afforded by these less commonly used elements.
This application is a continuation-in-part application of co-pending U.S. patent application Ser. No. 18/177,200, filed on Mar. 2, 2023, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63/326,548, filed on Apr. 1, 2022; 63/318,269, filed on Mar. 9, 2022; 63/400,416, filed on Aug. 24, 2022; 63/329,688, filed on Apr. 11, 2022; 63/395,173, filed on Aug. 4, 2022; 63/329,924, filed on Apr. 12, 2022; 63/401,800, filed on Aug. 29, 2022; 63/342,198, filed May 16, 2022; and 63/367,818, filed Jul. 7, 2022, the entire contents of all the above applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63326548 | Apr 2022 | US | |
| 63329924 | Apr 2022 | US | |
| 63395173 | Aug 2022 | US | |
| 63400416 | Aug 2022 | US | |
| 63329688 | Apr 2022 | US | |
| 63401800 | Aug 2022 | US | |
| 63342198 | May 2022 | US | |
| 63367818 | Jul 2022 | US | |
| 63318269 | Mar 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18177200 | Mar 2023 | US |
| Child | 18830929 | US |
