Patent Grant
12041846
The present invention relates to compounds for use as emitters, and devices, such as organic light emitting diodes, including the same.
Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of 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. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants.
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. 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.
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 EML device or a stack structure. Color may be measured using CIE coordinates, which are well known to the art.
One example of a green emissive molecule is tris(2-phenylpyridine) iridium, denoted Ir(ppy)3, which has the following structure:
In this, and later figures herein, we depict the dative bond from nitrogen to metal (here, Ir) as a straight line.
As used herein, the term “organic” includes polymeric materials as well as small molecule organic materials that may be used to fabricate organic opto-electronic devices. “Small molecule” refers to any organic material that is not a polymer, and “small molecules” may actually be quite large. Small molecules may include repeat units in some circumstances. For example, using a long chain alkyl group as a substituent does not remove a molecule from the “small molecule” class. Small molecules may also be incorporated into polymers, for example as a pendent group on a polymer backbone or as a part of the backbone. Small molecules may also serve as the core moiety of a dendrimer, which consists of a series of chemical shells built on the core moiety. The core moiety of a dendrimer may be a fluorescent or phosphorescent small molecule emitter. A dendrimer may be a “small molecule,” and it is believed that all dendrimers currently used in the field of OLEDs are small molecules.
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 processible” means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.
A ligand may be referred to as “photoactive” when it is believed that the ligand directly contributes to the photoactive properties of an emissive material. A ligand may be referred to as “ancillary” when it is believed that the ligand does not contribute to the photoactive properties of an emissive material, although an ancillary ligand may alter the properties of a photoactive ligand.
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.
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.
A compound having the formula:
Formula I is disclosed. In Formula I, R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution. X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″. R′, R″, R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any substitutions are optionally joined or fused into a ring. n is 1 or 2. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof. R has at least five carbon atoms.
An OLED is also disclosed, where the OLED comprises: an anode; a cathode; and an organic layer, disposed between the anode and the cathode, comprising a compound having the formula:
Formula I. In Formula I, R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution. X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″. R′, R″, R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any substitutions are optionally joined or fused into a ring. n is 1 or 2. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof. R has at least five carbon atoms.
A consumer product comprising the OLED is also disclosed.
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.
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 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 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 invention 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 invention 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 invention 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, 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, 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, and a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present invention, 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 degrees C.), but could be used outside this temperature range, for example, from −40 degree C. to +80 degree 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.
The term “halo,” “halogen,” or “halide” as used herein includes fluorine, chlorine, bromine, and iodine.
The term “alkyl” as used herein contemplates both straight and branched chain alkyl radicals. Preferred alkyl groups are those containing from one to fifteen 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 may be optionally substituted.
The term “cycloalkyl” as used herein contemplates cyclic alkyl radicals. Preferred cycloalkyl groups are those containing 3 to 10 ring carbon atoms and includes cyclopropyl, cyclopentyl, cyclohexyl, adamantyl, and the like. Additionally, the cycloalkyl group may be optionally substituted.
The term “alkenyl” as used herein contemplates both straight and branched chain alkene radicals. Preferred alkenyl groups are those containing two to fifteen carbon atoms. Additionally, the alkenyl group may be optionally substituted.
The term “alkynyl” as used herein contemplates both straight and branched chain alkyne radicals. Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group may be optionally substituted.
The terms “aralkyl” or “alylalkyl” as used herein are used interchangeably and contemplate an alkyl group that has as a substituent an aromatic group. Additionally, the aralkyl group may be optionally substituted.
The term “heterocyclic group” as used herein contemplates aromatic and non-aromatic cyclic radicals. Hetero-aromatic cyclic radicals also means heteroaryl. Preferred hetero-non-aromatic cyclic groups are 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, such as tetrahydrofuran, tetrahydropyran, and the like. Additionally, the heterocyclic group may be optionally substituted.
The term “aryl” or “aromatic group” as used herein contemplates single-ring groups and polycyclic ring systems. The polycyclic rings may have two or more rings in which two carbons are common to two adjoining rings (the rings are “fused”) wherein at least one of the rings is aromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls. Preferred aryl groups are those containing six to thirty carbon atoms, preferably six to twenty carbon atoms, more preferably six to twelve carbon atoms. Especially preferred is an aryl group having six carbons, ten carbons or twelve carbons. Suitable aryl groups include phenyl, biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene, preferably phenyl, biphenyl, triphenyl, triphenylene, fluorene, and naphthalene. Additionally, the aryl group may be optionally substituted.
The term “heteroaryl” as used herein contemplates single-ring hetero-aromatic groups that may include from one to five heteroatoms. The term heteroaryl also includes polycyclic hetero-aromatic systems having two or more 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, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls. Preferred heteroaryl groups are those containing three to thirty carbon atoms, preferably three to twenty carbon atoms, more preferably three to twelve carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocathazole, 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 may be optionally substituted.
The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group, aryl, and heteroaryl may be unsubstituted or may be substituted with one or more substituents selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
As used herein, “substituted” indicates that a substituent other than H is bonded to the relevant position, such as carbon. Thus, for example, where R′ is mono-substituted, then one R′ must be other than H. Similarly, where R′ is di-substituted, then two of R′ must be other than H. Similarly, where R′ is unsubstituted, R′ is hydrogen for all available positions. The maximum number of substitutions possible in a structure will depend on the number of atoms with available valencies.
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 fragment can be replaced by a nitrogen atom, for example, and without any limitation, 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.
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.
Disclosed herein are novel polycyclic substituents. Phosphorescent emitters with these substituents show higher external quantum efficiency (EQE) in devices. In the field of organic chemistry, a polycyclic compound is an organic chemical featuring several closed rings of atoms, primarily carbon. These ring substructures comprise cycloalkanes, aromatics, and other ring types. They come in sizes of three atoms and upward, and in combinations of linkages that include tethering (such as in biaryls), fusing (edge-to-edge, such as in anthracene and steroids), links via a single atom (such as in spiro compounds), and bridged cyclics such as adamantane. The term “polycyclic” is used in this disclosure to include rings including many rings as well as structures such as bicyclic, tricyclic, and tetracyclic.
According to an aspect of the present disclosure, heteroleptic tris-cyclometalated Iridium (III) complexes that has a high efficiency in OLED device are disclosed.
A compound is disclosed having the formula [LA]3-nIr[LB]n, having the structure:
Formula I. In Formula I, R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution. X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″. Each of R′, R″, R1, R2, R3, R4, and R5 is independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any substitutions are optionally joined or fused into a ring. n is 1 or 2. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof. R has at least five carbon atoms.
In some embodiments, each of R′, R″, R1, R2, R3, R4, and R5 is independently selected from the group consisting of hydrogen, deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, and combinations thereof.
In some embodiments, R has at least six carbon atoms. In some embodiments, R has at least seven carbon atoms.
In some embodiments, n is 2. In some embodiments, X is O.
In some embodiments, R comprises a cycloalkyl or heterocycloalkyl. In some embodiments, R1, R2, R3, R4, and R5 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, aryl, and combinations thereof.
In some embodiments, R is selected from the group consisting of:
In some embodiments of the compound, the compound is selected from the group consisting of
wherein R6 is selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
In some embodiments of the compound, LA is selected from the group consisting of LA1 to LA371 having a structure according to
in which R, R1, RA, RB, RC, RD, and RE are defined as provided below:
In some embodiments of the compound, LB is selected from the group consisting of LB1 to LB1471 having a structure according to
wherein RB1, RB2, RB3, and RB4 are defined as provided below:
In the embodiments of the compound where LB is one of LB1 to LB1471 defined above, the compound is selected from the group consisting of Compound A-x having the formula Ir(LA1)(LBj)2 or Compound B-x having the formula Ir(LAi)2(LBj); wherein x is an integer defined by x=1471i+j−1471, wherein i is an integer from 1 to 371, j is an integer from 1 to 1471, and wherein LA1 to LA371 have the following formula:
wherein R, R1, R2, R3, R4, R5, and R6 are defined as provided below:
An OLED is also disclosed, where the OLED comprises: an anode; a cathode; and an organic layer, disposed between the anode and the cathode, comprising a compound having the formula:
Formula I. In Formula I, R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution. X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″. Each of R′, R″, R1, R2, R3, R4, and R5 is independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any substitutions are optionally joined or fused into a ring. n is 1 or 2. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof. R has at least five carbon atoms.
In some embodiments of the OLED, each of R′, R″, R1, R2, R3, R4, and R5 is independently selected from the group consisting of hydrogen, deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, and combinations thereof.
In some embodiments of the OLED, the organic layer further comprises a host, wherein host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.
In some embodiments of the OLED, R in the compound has at least six carbon atoms. In some embodiments, R has at least seven carbon atoms.
A consumer product comprising the OLED is also disclosed, where the OLED comprises: an anode; a cathode; and an organic layer, disposed between the anode and the cathode, comprising a compound having the formula:
Formula I. In Formula I, R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution. X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″. R′, R″, R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any substitutions are optionally joined or fused into a ring. n is 1 or 2. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof. R has at least five carbon atoms.
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.
An emissive region in an organic light emitting device, the emissive region comprising a compound having the formula:
Formula I. In Formula I, R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution. X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″. R′, R″, R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any substitutions are optionally joined or fused into a ring. n is 1 or 2. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof. R has at least five carbon atoms.
In some embodiments of the emissive region, the compound is an emissive dopant or a non-emissive dopant.
In some embodiments, the emissive region further comprises a host, wherein the host comprises at least one selected from the group consisting of metal complex, triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-triphenylene, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.
In some embodiments, the emissive region further comprises a host, wherein the host is selected from the group consisting of:
and combinations thereof.
In some embodiments, the compound can be an emissive dopant. In some embodiments, the compound can produce emissions via phosphorescence, fluorescence, thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence), triplet-triplet annihilation, or combinations of these processes.
According to another aspect, a formulation comprising the compound described herein is also disclosed.
The OLED disclosed herein can be incorporated into one or more of a consumer product, an electronic component module, and a lighting panel. The organic layer can be an emissive layer and the compound can be an emissive dopant in some embodiments, while the compound can be a non-emissive dopant in other embodiments.
The organic layer can also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the hosts used maybe a) bipolar, b) electron transporting, c) hole transporting or d) wide band gap materials that play little role in charge transport. In some embodiments, the host can include a metal complex. The host can be a triphenylene containing benzo-fused thiophene or benzo-fused furan. Any substituent in the host can be 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≡C—CnH2n+1, Ar1, Ar1—Ar2, and CnH2n—Ar1, or the host has no substitutions. In the preceding substituents n can range from 1 to 10; and Ar1 and Ar2 can be independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof. The host can be an inorganic compound. For example a Zn containing inorganic material e.g. ZnS.
The host can be a compound comprising at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene. The host can include a metal complex. The host can be, but is not limited to, a specific compound selected from the group consisting of:
and combinations thereof.
Additional information on possible hosts is provided below.
In yet another aspect of the present disclosure, a formulation that comprises the novel compound disclosed herein is described. The formulation can include one or more components selected from the group consisting of a solvent, a host, a hole injection material, hole transport material, and an electron transport layer material, disclosed herein.
Combination with Other Materials
The materials described herein as useful for a particular layer in an organic light emitting device may be used in combination with a wide variety of other materials present in the device. For example, emissive dopants disclosed herein 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 compounds disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that may be useful in combination.
Conductivity Dopants:
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.
Non-limiting examples of the conductivity dopants that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: EP01617493, EP01968131, EP2020694, EP2684932, US20050139810, US20070160905, US20090167167, US2010288362, WO06081780, WO2009003455, WO2009008277, WO2009011327, WO2014009310, US2007252140, US2015060804 and US2012146012.
HIL/HTL:
A hole injecting/transporting material to be used in the present invention 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 Ar may be unsubstituted or may be substituted by a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
In one aspect, Ar1 to Ar9 is independently selected from the group consisting of:
wherein k is an integer from 1 to 20; X101 to X108 is C (including CH) or N; Z101 is NAr1, O, or S; Ar1 has the same group defined above.
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, Y101 and Y102 are independently selected from C, N, O, P, and S; L101 is an ancillary 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 one aspect, (Y101-Y102) is a 2-phenylpyridine derivative. In another aspect, (Y101-Y102) is a carbene ligand. In another aspect, Met is selected from Ir, Pt, Os, and Zn. In a further aspect, the metal complex has a smallest oxidation potential in solution vs. Fc+/Fc couple less than about 0.6 V.
Non-limiting examples of the HIL and HTL materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: CN102702075, DE102012005215, EP01624500, EP01698613, EP01806334, EP01930964, EP01972613, EP01997799, EP02011790, EP02055700, EP02055701, EP1725079, EP2085382, EP2660300, EP650955, JP07-073529, JP2005112765, JP2007091719, JP2008021687, JP2014-009196, KR20110088898, KR20130077473, TW201139402, U.S. Ser. No. 06/517,957, US20020158242, US20030162053, US20050123751, US20060182993, US20060240279, US20070145888, US20070181874, US20070278938, US20080014464, US20080091025, US20080106190, US20080124572, US20080145707, US20080220265, US20080233434, US20080303417, US2008107919, US20090115320, US20090167161, US2009066235, US2011007385, US20110163302, US2011240968, US2011278551, US2012205642, US2013241401, US20140117329, US2014183517, U.S. Pat. Nos. 5,061,569, 5,639,914, WO05075451, WO07125714, WO08023550, WO08023759, WO2009145016, WO2010061824, WO2011075644, WO2012177006, WO2013018530, WO2013039073, WO2013087142, WO2013118812, WO2013120577, WO2013157367, WO2013175747, WO2014002873, WO2014015935, WO2014015937, WO2014030872, WO2014030921, WO2014034791, WO2014104514, WO2014157018.
EBL:
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 the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and/or higher triplet energy than one or more of the hosts closest to the EBL interface. In one aspect, the compound used in EBL contains the same molecule or the same functional groups used as one of the hosts described below.
Host:
The light emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as light emitting material, and may contain a host material using the metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complexes or organic compounds may be used as long as the triplet energy of the host is larger than that of the dopant. Any host material may be used with any dopant so long as the triplet criteria is satisfied.
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, Y103 and Y104 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 one aspect, the metal complexes are:
wherein (O—N) is a bidentate ligand, having metal coordinated to atoms O and N.
In another aspect, Met is selected from Ir and Pt. In a further aspect, (Y103-Y104) is a carbene ligand.
Examples of other organic compounds used as host are 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, 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 option within each group may be unsubstituted or may be substituted by a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
In one aspect, the host compound contains at least one of the following groups in the molecule:
wherein R101 is selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. k is an integer from 0 to 20 or 1 to 20. X101 to X108 are independently selected from C (including CH) or N. Z101 and Z102 are independently selected from NR101, O, or S.
Non-limiting examples of the host materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: EP2034538, EP2034538A, EP2757608, JP2007254297, KR20100079458, KR20120088644, KR20120129733, KR20130115564, TW201329200, US20030175553, US20050238919, US20060280965, US20090017330, US20090030202, US20090167162, US20090302743, US20090309488, US20100012931, US20100084966, US20100187984, US2010187984, US2012075273, US2012126221, US2013009543, US2013105787, US2013175519, US2014001446, US20140183503, US20140225088, US2014034914, U.S. Pat. No. 7,154,114, WO2001039234, WO2004093207, WO2005014551, WO2005089025, WO2006072002, WO2006114966, WO2007063754, WO2008056746, WO2009003898, WO2009021126, WO2009063833, WO2009066778, WO2009066779, WO2009086028, WO2010056066, WO2010107244, WO2011081423, WO2011081431, WO2011086863, WO2012128298, WO2012133644, WO2012133649, WO2013024872, WO2013035275, WO2013081315, WO2013191404, WO2014142472,
Additional Emitters:
One or more additional emitter dopants may be used in conjunction with the compound of the present disclosure. Examples of the additional emitter dopants are not particularly limited, and any compounds may be used as long as the compounds are typically used as emitter materials. Examples of suitable emitter materials include, but are not limited to, compounds which can produce emissions via phosphorescence, fluorescence, thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence), triplet-triplet annihilation, or combinations of these processes.
Non-limiting examples of the emitter materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: CN103694277, CN1696137, EB01238981, EP01239526, EP01961743, EP1239526, EP1244155, EP1642951, EP1647554, EP1841834, EP1841834B, EP2062907, EP2730583, JP2012074444, JP2013110263, JP4478555, KR1020090133652, KR20120032054, KR20130043460, TW201332980, U.S. Ser. No. 06/699,599, U.S. Ser. No. 06/916,554, US20010019782, US20020034656, US20030068526, US20030072964, US20030138657, US20050123788, US20050244673, US2005123791, US2005260449, US20060008670, US20060065890, US20060127696, US20060134459, US20060134462, US20060202194, US20060251923, US20070034863, US20070087321, US20070103060, US20070111026, US20070190359, US20070231600, US2007034863, US2007104979, US2007104980, US2007138437, US2007224450, US2007278936, US20080020237, US20080233410, US20080261076, US20080297033, US200805851, US2008161567, US2008210930, US20090039776, US20090108737, US20090115322, US20090179555, US2009085476, US2009104472, US20100090591, US20100148663, US20100244004, US20100295032, US2010102716, US2010105902, US2010244004, US2010270916, US20110057559, US20110108822, US20110204333, US2011215710, US2011227049, US2011285275, US2012292601, US20130146848, US2013033172, US2013165653, US2013181190, US2013334521, US20140246656, US2014103305, U.S. Pat. Nos. 6,303,238, 6,413,656, 6,653,654, 6,670,645, 6,687,266, 6,835,469, 6,921,915, 7,279,704, 7,332,232, 7,378,162, 7,534,505, 7,675,228, 7,728,137, 7,740,957, 7,759,489, 7,951,947, 8,067,099, 8,592,586, 8,871,361, WO06081973, WO06121811, WO07018067, WO07108362, WO07115970, WO07115981, WO08035571, WO2002015645, WO2003040257, WO2005019373, WO2006056418, WO2008054584, WO2008078800, WO2008096609, WO2008101842, WO2009000673, WO2009050281, WO2009100991, WO2010028151, WO2010054731, WO2010086089, WO2010118029, WO2011044988, WO2011051404, WO2011107491, WO2012020327, WO2012163471, WO2013094620, WO2013107487, WO2013174471, WO2014007565, WO2014008982, WO2014023377, WO2014024131, WO2014031977, WO2014038456, WO2014112450.
HBL:
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 from the vacuum level) and/or higher triplet energy than the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and/or higher triplet energy than one or more of the hosts closest to the HBL interface.
In one aspect, compound used in HBL contains the same molecule or the same functional groups used as host described above.
In another aspect, compound used in HBL contains at least one of the following groups in the molecule:
wherein k is an integer from 1 to 20; L101 is an another ligand, k′ is an integer from 1 to 3.
ETL:
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 one aspect, compound used in ETL contains at least one of the following groups in the molecule:
wherein R101 is selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. Ar1 to Ar3 has the similar definition as Ar's mentioned above. k is an integer from 1 to 20. X101 to X108 is selected from C (including CH) or N.
In another aspect, 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.
Non-limiting examples of the ETL materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: CN103508940, EP01602648, EP01734038, EP01956007, JP2004-022334, JP2005149918, JP2005-268199, KR0117693, KR20130108183, US20040036077, US20070104977, US2007018155, US20090101870, US20090115316, US20090140637, US20090179554, US2009218940, US2010108990, US2011156017, US2011210320, US2012193612, US2012214993, US2014014925, US2014014927, US20140284580, U.S. Pat. Nos. 6,656,612, 8,415,031, WO2003060956, WO2007111263, WO2009148269, WO2010067894, WO2010072300, WO2011074770, WO2011105373, WO2013079217, WO2013145667, WO2013180376, WO2014104499, WO2014104535,
Charge Generation Layer (CGL)
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 above-mentioned compounds used in each layer of the OLED device, the hydrogen atoms can be partially or fully deuterated. Thus, any specifically listed substituent, such as, without limitation, methyl, phenyl, pyridyl, etc. may be undeuterated, partially deuterated, and fully deuterated versions thereof. Similarly, classes of substituents such as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc. also may be undeuterated, partially deuterated, and fully deuterated versions thereof.
Step 1
One 1 L 3-neck flask was charged with 2,4-dichloro-5-methylpyridine (15.28 g, 94 mmol), dibenzo[b,d]furan-4-ylboronic acid (20.0 g, 94 mmol), sodium carbonate (30.0 g, 283 mmol), DME (400 ml), water (40 ml) and tetrakis(triphenylphosphine)palladium(0) (2.180 g, 1.887 mmol). The reaction mixture was heated to reflux for 16 hrs. The reaction was then diluted with 150 ml water and extracted with 3×100 ml EtOAc. The extracts were washed with 100 ml water, dried and evaporated to dryness. The residue was purified by column chromatography (SiO2) to yield the desired product(19.8 g).
Step 2
One 500 ml 3-neck oven dried flask was charged with Pd2(dba)3 (0.411 g, 0.449 mmol), X phos (0.857 g, 1.797 mmol), 4-chloro-2-(dibenzo[b,d]furan-4-yl)-5-methylpyridine (4.4 g, 14.98 mmol), THF (75 ml) and cyclohexylzinc(II) bromide (0.5M in THF) (44.9 ml, 22.47 mmol). The reaction was heated to 65° C. for 24 hours. The reaction was then diluted with 150 ml water and extracted with 3×100 ml EtOAc. The extracts were washed with 100 ml water, dried and evaporated to dryness. The residue was purified by column chromatography (SiO2) to yield the desired product (9.3 g).
Step 3
One 200 ml flask was charged with 4-cyclohexyl-2-(dibenzo[b,d]furan-4-yl)-5-methylpyridine (4.7 g, 13.76 mmol), DMSO-d6 (38.5 ml, 551 mmol) and sodium 2-methylpropan-2-olate (0.661 g, 6.88 mmol). The reaction was heated to 60° C. for overnight. The reaction was then diluted with 150 ml water and extracted with 3×100 ml EtOAc. The extracts were washed with 100 ml water, dried and evaporated to dryness. The residue was purified by column chromatography (SiO2) to yield the desired product (4.2 g).
Step 4
One 250 ml r.b. flask was charged with 4-(cyclohexyl-1-d)-2-(dibenzo[b,d]furan-4-yl)-5-(methyl-d3)pyridine(1.76 g, 5.12 mmol), Iridium metal complexes(2.0 g, 2.56 mmol), Methanol (30 ml) and Ethanol (30.0 ml). The reaction was heated to 80° C. for 5 days. The solvent was evaporated to dryness. The residue was purified by column chromatography (SiO2) to yield the desired product (0.55 g).
All example devices were fabricated by high vacuum (<10−7 Torr) thermal evaporation. The anode electrode was 800 Å of indium tin oxide (ITO). The cathode consisted of 10 Å of Liq (8-hydroxyquinoline lithium) followed by 1,000 Å of Al. All devices were encapsulated with a glass lid sealed with an epoxy resin in a nitrogen glove box (<1 ppm of H2O and O2) immediately after fabrication with a moisture getter incorporated inside the package. The organic stack of the device examples consisted of sequentially, from the ITO Surface: 100 Å of HAT-CN as the hole injection layer (HIL); 450 Å of HTM as a hole transporting layer (HTL); emissive layer (EML) with thickness 400 Å. Emissive layer containing H-host (H1): E-host (H2) in 6:4 ratio and 12 weight % of green emitter; 350 Å of Liq (8-hydroxyquinoline lithium) doped with 40% of ETM as the ETL. The device structure is shown in Table 1 below. Table 1 shows the schematic device structure. The chemical structures of the device materials are shown below.
Upon fabrication, electroluminance (EL) and current density-voltage-luminance (J-V-L) of the devices were measured at DC 10 mA/cm2. Device performance is tabulated in Table 2 below.
Referring to Table 2, comparing Ir(LA96LB370) with the comparative example; the inventive compound has higher efficiency and lower voltage than the comparative compound. Presumably, the alkyl substitution in the peripheral ring has better alignment with transition dipolar moment of the molecule. The concept is illustrated in the diagram shown in
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.
This application is a continuation application of copending U.S. patent application Ser. No. 17/320,422, filed on May 14, 2021, which is a continuation of U.S. patent application Ser. No. 15/918,179, filed Mar. 12, 2018, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 62/479,730, filed Mar. 31, 2017 and U.S. Provisional Application No. 62/478,072, filed Mar. 29, 2017, the entire contents of which are incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4769292 | Tang et al. | Sep 1988 | A |
| 5061569 | VanSlyke et al. | Oct 1991 | A |
| 5247190 | Friend et al. | Sep 1993 | A |
| 5703436 | Forrest et al. | Dec 1997 | A |
| 5707745 | Forrest et al. | Jan 1998 | A |
| 5834893 | Bulovic et al. | Nov 1998 | A |
| 5844363 | Gu et al. | Dec 1998 | A |
| 6013982 | Thompson et al. | Jan 2000 | A |
| 6087196 | Sturm et al. | Jul 2000 | A |
| 6091195 | Forrest et al. | Jul 2000 | A |
| 6097147 | Baldo et al. | Aug 2000 | A |
| 6294398 | Kim et al. | Sep 2001 | B1 |
| 6303238 | Thompson et al. | Oct 2001 | B1 |
| 6337102 | Forrest et al. | Jan 2002 | B1 |
| 6468819 | Kim et al. | Oct 2002 | B1 |
| 6528187 | Okada | Mar 2003 | B1 |
| 6687266 | Ma et al. | Feb 2004 | B1 |
| 6835469 | Kwong et al. | Dec 2004 | B2 |
| 6921915 | Takiguchi et al. | Jul 2005 | B2 |
| 7087321 | Kwong et al. | Aug 2006 | B2 |
| 7090928 | Thompson et al. | Aug 2006 | B2 |
| 7154114 | Brooks et al. | Dec 2006 | B2 |
| 7250226 | Tokito et al. | Jul 2007 | B2 |
| 7279704 | Walters et al. | Oct 2007 | B2 |
| 7332232 | Ma et al. | Feb 2008 | B2 |
| 7338722 | Thompson et al. | Mar 2008 | B2 |
| 7393599 | Thompson et al. | Jul 2008 | B2 |
| 7396598 | Takeuchi et al. | Jul 2008 | B2 |
| 7431968 | Shtein et al. | Oct 2008 | B1 |
| 7445855 | Mackenzie et al. | Nov 2008 | B2 |
| 7534505 | Lin et al. | May 2009 | B2 |
| 8709615 | Kottas | Apr 2014 | B2 |
| 8722205 | Xia | May 2014 | B2 |
| 11056658 | Tsai | Jul 2021 | B2 |
| 11678563 | Tsai | Jun 2023 | B2 |
| 20020034656 | Thompson et al. | Mar 2002 | A1 |
| 20020134984 | Igarashi | Sep 2002 | A1 |
| 20020158242 | Son et al. | Oct 2002 | A1 |
| 20030138657 | Li et al. | Jul 2003 | A1 |
| 20030152802 | Tsuboyama et al. | Aug 2003 | A1 |
| 20030162053 | Marks et al. | Aug 2003 | A1 |
| 20030175553 | Thompson et al. | Sep 2003 | A1 |
| 20030230980 | Forrest et al. | Dec 2003 | A1 |
| 20040036077 | Ise | Feb 2004 | A1 |
| 20040137267 | Igarashi et al. | Jul 2004 | A1 |
| 20040137268 | Garashi et al. | Jul 2004 | A1 |
| 20040174116 | Lu et al. | Sep 2004 | A1 |
| 20050025993 | Thompson et al. | Feb 2005 | A1 |
| 20050112407 | Ogasawara et al. | May 2005 | A1 |
| 20050238919 | Ogasawara | Oct 2005 | A1 |
| 20050244673 | Satoh et al. | Nov 2005 | A1 |
| 20050260441 | Thompson et al. | Nov 2005 | A1 |
| 20050260449 | Walters et al. | Nov 2005 | A1 |
| 20060008670 | Lin et al. | Jan 2006 | A1 |
| 20060202194 | Jeong et al. | Sep 2006 | A1 |
| 20060240279 | Adamovich et al. | Oct 2006 | A1 |
| 20060251923 | Lin et al. | Nov 2006 | A1 |
| 20060263635 | Ise | Nov 2006 | A1 |
| 20060280965 | Kwong et al. | Dec 2006 | A1 |
| 20070190359 | Knowles et al. | Aug 2007 | A1 |
| 20070278938 | Yabunouchi et al. | Dec 2007 | A1 |
| 20080015355 | Schafer et al. | Jan 2008 | A1 |
| 20080018221 | Egen et al. | Jan 2008 | A1 |
| 20080106190 | Yabunouchi et al. | May 2008 | A1 |
| 20080124572 | Mizuki et al. | May 2008 | A1 |
| 20080220265 | Xia et al. | Sep 2008 | A1 |
| 20080297033 | Knowles et al. | Dec 2008 | A1 |
| 20090008605 | Kawamura et al. | Jan 2009 | A1 |
| 20090009065 | Nishimura et al. | Jan 2009 | A1 |
| 20090017330 | Iwakuma et al. | Jan 2009 | A1 |
| 20090030202 | Iwakuma et al. | Jan 2009 | A1 |
| 20090039776 | Yamada et al. | Feb 2009 | A1 |
| 20090045730 | Nishimura et al. | Feb 2009 | A1 |
| 20090045731 | Nishimura et al. | Feb 2009 | A1 |
| 20090101870 | Prakash et al. | Apr 2009 | A1 |
| 20090108737 | Kwong et al. | Apr 2009 | A1 |
| 20090115316 | Zheng et al. | May 2009 | A1 |
| 20090165846 | Johannes et al. | Jul 2009 | A1 |
| 20090167162 | Lin et al. | Jul 2009 | A1 |
| 20090179554 | Kuma et al. | Jul 2009 | A1 |
| 20100244004 | Xia | Sep 2010 | A1 |
| 20120153816 | Takizawa | Jun 2012 | A1 |
| 20120292601 | Kottas | Nov 2012 | A1 |
| 20130026452 | Kottas | Jan 2013 | A1 |
| 20130119354 | Ma | May 2013 | A1 |
| 20140231755 | Xia | Aug 2014 | A1 |
| 20160049597 | Ma | Feb 2016 | A1 |
| 20160049599 | Ma | Feb 2016 | A1 |
| 20160093814 | Hwang | Mar 2016 | A1 |
| 20160155962 | Hwang | Jun 2016 | A1 |
| 20160155963 | Hwang | Jun 2016 | A1 |
| 20170069848 | Zeng | Mar 2017 | A1 |
| 20180273563 | Choi | Sep 2018 | A1 |
| 20180282356 | Ji | Oct 2018 | A1 |
| Number | Date | Country |
|---|---|---|
| 0650955 | May 1995 | EP |
| 1238981 | Sep 2002 | EP |
| 1725079 | Nov 2006 | EP |
| 2034538 | Mar 2009 | EP |
| 200511610 | Jan 2005 | JP |
| 2007123392 | May 2007 | JP |
| 2007254297 | Oct 2007 | JP |
| 2008074939 | Apr 2008 | JP |
| 0139234 | May 2001 | WO |
| 0202714 | Jan 2002 | WO |
| 02015654 | Feb 2002 | WO |
| 03040257 | May 2003 | WO |
| 03060956 | Jul 2003 | WO |
| 2004093207 | Oct 2004 | WO |
| 2004107822 | Dec 2004 | WO |
| 2005014551 | Feb 2005 | WO |
| 2005019373 | Mar 2005 | WO |
| 2005030900 | Apr 2005 | WO |
| 2005089025 | Sep 2005 | WO |
| 2005123873 | Dec 2005 | WO |
| 2006009024 | Jan 2006 | WO |
| 2006056418 | Jun 2006 | WO |
| 2006072002 | Jul 2006 | WO |
| 2006082742 | Aug 2006 | WO |
| 2006098120 | Sep 2006 | WO |
| 2006100298 | Sep 2006 | WO |
| 2006103874 | Oct 2006 | WO |
| 2006114966 | Nov 2006 | WO |
| 2006132173 | Dec 2006 | WO |
| 2007002683 | Jan 2007 | WO |
| 2007004380 | Jan 2007 | WO |
| 2007063754 | Jun 2007 | WO |
| 2007063796 | Jun 2007 | WO |
| 2008056746 | May 2008 | WO |
| 2008101842 | Aug 2008 | WO |
| 2008132085 | Nov 2008 | WO |
| 2009000673 | Dec 2008 | WO |
| 2009003898 | Jan 2009 | WO |
| 2009008311 | Jan 2009 | WO |
| 2009018009 | Feb 2009 | WO |
| 2009021126 | Feb 2009 | WO |
| 2009050290 | Apr 2009 | WO |
| 2009062578 | May 2009 | WO |
| 2009063833 | May 2009 | WO |
| 2009066778 | May 2009 | WO |
| 2009066779 | May 2009 | WO |
| 2009086028 | Jul 2009 | WO |
| 2009100991 | Aug 2009 | WO |
| Entry |
|---|
| Adachi, Chihaya et al., “Organic Electroluminescent Device Having a Hole Conductor as an Emitting Layer,” Appl. Phys. Lett., 55(15): 1489-1491 (1989). |
| Adachi, Chihaya et al., “Nearly 100% Internal Phosphorescence Efficiency in an Organic Light Emitting Device,” J. Appl. Phys., 90(10): 5048-5051 (2001). |
| Adachi, Chihaya et al., “High-Efficiency Red Electrophosphorescence Devices,” Appl. Phys. Lett., 78(11)1622-1624 (2001). |
| Aonuma, Masaki et al., “Material Design of Hole Transport Materials Capable of Thick-Film Formation in Organic Light Emitting Diodes,” Appl. Phys. Lett., 90, Apr. 30, 2007, 183503-1-183503-3. |
| Baldo et al., Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices, Nature, vol. 395, 151-154, (1998). |
| Baldo et al., Very high-efficiency green organic light-emitting devices based on electrophosphorescence, Appl. Phys. Lett., vol. 75, No. 1, 4-6 (1999). |
| Gao, Zhiqiang et al., “Bright-Blue Electroluminescence From a Silyl-Substituted ter-(phenylene-vinylene) derivative,” Appl. Phys. Lett., 74(6): 865-867 (1999). |
| Guo, Tzung-Fang et al., “Highly Efficient Electrophosphorescent Polymer Light-Emitting Devices,” Organic Electronics, 1: 15-20 (2000). |
| Hamada, Yuji et al., “High Luminance in Organic Electroluminescent Devices with Bis(10-hydroxybenzo[h]quinolinato) beryllium as an Emitter, ” Chem. Lett., 905-906 (1993). |
| Holmes, R.J. et al., “Blue Organic Electrophosphorescence Using Exothermic Host-Guest Energy Transfer,” Appl. Phys. Lett., 82(15):2422-2424 (2003). |
| Hu, Nan-Xing et al., “Novel High Tg Hole-Transport Molecules Based on Indolo[3,2-b]carbazoles for Organic Light-Emitting Devices,” Synthetic Metals, 111-112:421-424 (2000). |
| Huang, Jinsong et al., “Highly Efficient Red-Emission Polymer Phosphorescent Light-Emitting Diodes Based on Two Novel Tris(1-phenylisoquinolinato-C2, N)iridium(III) Derivatives,” Adv. Mater., 19:739-743 (2007). |
| Huang, Wei-Sheng et al., “Highly Phosphorescent Bis-Cyclometalated Iridium Complexes Containing Benzoimidazole-Based Ligands,” Chem. Mater., 16(12):2480-2488 (2004). |
| Hung, L.S. et al., “Anode Modification in Organic Light-Emitting Diodes by Low-Frequency Plasma Polymerization of CHF3,” Appl. Phys. Lett., 78(5):673-675 (2001). |
| Ikai, Masamichi et al., “Highly Efficient Phosphorescence From Organic Light-Emitting Devices with an Exciton-Block Layer,” Appl. Phys. Lett., 79(2):156-158 (2001). |
| Ikeda, Hisao et al., “P-185 Low-Drive-Voltage OLEDs with a Buffer Layer Having Molybdenum Oxide,” SID Symposium Digest, 37:923-926 (2006). |
| Inada, Hiroshi and Shirota, Yasuhiko, “1,3,5-Tris[4-(diphenylamino)phenyl]benzene and its Methylsubstituted Derivatives as a Novel Class of Amorphous Molecular Materials,” J. Mater. Chem., 3(3):319-320 (1993). |
| Kanno, Hiroshi et al., “Highly Efficient and Stable Red Phosphorescent Organic Light-Emitting Device Using bis[2-(2-benzothiazoyl)phenolato]zinc(II) as host material,” Appl. Phys. Lett., 90:123509-1-123509-3 (2007). |
| Kido, Junji et al., 1,2,4-Triazole Derivative as an Electron Transport Layer in Organic Electroluminescent Devices, Jpn. J. Appl. Phys., 32:L917-L920 (1993). |
| Kuwabara, Yoshiyuki et al., “Thermally Stable Multilayered Organic Electroluminescent Devices Using Novel Starburst Molecules, 4,4′,4″-Tri(N-carbazolyl)triphenylamine (TCTA) and 4,4′,4″-Tris(3-methylphenylphenyl-amino) triphenylamine (m-MTDATA), as Hole-Transport Materials,” Adv. Mater., 6(9):677-679 (1994). |
| Kwong, Raymond C. et al., “High Operational Stability of Electrophosphorescent Devices,” Appl. Phys. Lett., 81(1)162-164 (2002). |
| Lamansky, Sergey et al., “Synthesis and Characterization of Phosphorescent Cyclometalated Iridium Complexes,” Inorg. Chem., 40(7):1704-1711 (2001). |
| Lee, Chang-Lyoul et al., “Polymer Phosphorescent Light-Emitting Devices Doped with Tris(2-phenylpyridine) Iridium as a Triplet Emitter,” Appl. Phys. Lett., 77(15):2280-2282 (2000). |
| Lo, Shih-Chun et al., “Blue Phosphorescence from Iridium(III) Complexes at Room Temperature,” Chem. Mater., 18 (21)5119-5129 (2006). |
| Ma, Yuguang et al., “Triplet Luminescent Dinuclear-Gold(I) Complex-Based Light-Emitting Diodes with Low Turn-On voltage,” Appl. Phys. Lett., 74(10):1361-1363 (1999). |
| Mi, Bao-Xiu et al., “Thermally Stable Hole-Transporting Material for Organic Light-Emitting Diode an Isoindole Derivative,” Chem. Mater., 15(16):3148-3151 (2003). |
| Nishida, Jun-ichi et al., “Preparation, Characterization, and Electroluminescence Characteristics of α-Diimine-type Platinum(II) Complexes with Perfluorinated Phenyl Groups as Ligands,” Chem. Lett., 34(4): 592-593 (2005). |
| Niu, Yu-Hua et al., “Highly Efficient Electrophosphorescent Devices with Saturated Red Emission from a Neutral Osmium Complex,” Chem. Mater., 17(13):3532-3536 (2005). |
| Noda, Tetsuya and Shirota, Yasuhiko, “5,5′-Bis(dimesitylboryl)-2,2′-bithiophene and 5,5″-Bis (dimesitylboryl)-2,2′5′,2″-terthiophene as a Novel Family of Electron-Transporting Amorphous Molecular Materials,” J. Am. Chem. Soc., 120 (37):9714-9715 (1998). |
| Okumoto, Kenji et al., “Green Fluorescent Organic Light-Emitting Device with External Quantum Efficiency of Nearly 10%,” Appl. Phys. Lett., 89:063504-1-063504-3 (2006). |
| Palilis, Leonidas C., “High Efficiency Molecular Organic Light-Emitting Diodes Based on Silole Derivatives and Their Exciplexes,” Organic Electronics, 4:113-121 (2003). |
| Paulose, Betty Marie Jennifer S. et al., “First Examples of Alkenyl Pyridines as Organic Ligands for Phosphorescent Iridium Complexes,” Adv. Mater., 16(22):2003-2007 (2004). |
| Ranjan, Sudhir et al., “Realizing Green Phosphorescent Light-Emitting Materials from Rhenium(I) Pyrazolato Diimine Complexes,” Inorg. Chem., 42(4):1248-1255 (2003). |
| Sakamoto, Youichi et al., “Synthesis, Characterization, and Electron-Transport Property of Perfluorinated Phenylene Dendrimers,” J. Am. Chem. Soc., 122(8):1832-1833 (2000). |
| Salbeck, J. et al., “Low Molecular Organic Glasses for Blue Electroluminescence,” Synthetic Metals, 91: 209-215 (1997). |
| Shirota, Yasuhiko et al., “Starburst Molecules Based on pi-Electron Systems as Materials for Organic Electroluminescent Devices,” Journal of Luminescence, 72-74:985-991 (1997). |
| Sotoyama, Wataru et al., “Efficient Organic Light-Emitting Diodes with Phosphorescent Platinum Complexes Containing NCN-Coordinating Tridentate Ligand,” Appl. Phys. Lett., 86:153505-1-153505-3 (2005). |
| Sun, Yiru and Forrest, Stephen R., “High-Efficiency White Organic Light Emitting Devices with Three Separate Phosphorescent Emission Layers,” Appl. Phys. Lett., 91:263503-1-263503-3 (2007). |
| T. Östergard et al., “Langmuir-Blodgett Light-Emitting Diodes of Poly(3-Hexylthiophene) Electro-Optical Characteristics Related to Structure,” Synthetic Metals, 88:171-177 (1997). |
| Takizawa, Shin-ya et al., “Phosphorescent Iridium Complexes Based on 2-Phenylimidazo[1,2- α]pyridine Ligands Tuning of Emission Color toward the Blue Region and Application to Polymer Light-Emitting Devices,” Inorg. Chem., 46(10):4308-4319 (2007). |
| Tang, C.W. and VanSlyke, S.A., “Organic Electroluminescent Diodes,” Appl. Phys. Lett., 51(12):913-915 (1987). |
| Tung, Yung-Liang et al., “Organic Light-Emitting Diodes Based on Charge-Neutral Ru II PHosphorescent Emitters,” Adv. Mater., 17(8)1059-1064 (2005). |
| Van Slyke, S. A. et al., “Organic Electroluminescent Devices with Improved Stability,” Appl. Phys. Lett., 69(15):2160-2162 (1996). |
| Wang, Y. et al., “Highly Efficient Electroluminescent Materials Based on Fluorinated Organometallic Iridium Compounds,” Appl. Phys. Lett., 79(4):449-451 (2001). |
| Wong, Keith Man-Chung et al., A Novel Class of Phosphorescent Gold(III) Alkynyl-Based Organic Light-Emitting Devices with Tunable Colour, Chem. Commun., 2906-2908 (2005). |
| Wong, Wai-Yeung, “Multifunctional Iridium Complexes Based on Carbazole Modules as Highly Efficient Electrophosphors,” Angew. Chem. Int. Ed., 45:7800-7803 (2006). |
| Number | Date | Country | |
|---|---|---|---|
| 20230276694 A1 | Aug 2023 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62479730 | Mar 2017 | US | |
| 62478072 | Mar 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17320422 | May 2021 | US |
| Child | 18301353 | US | |
| Parent | 15918179 | Mar 2018 | US |
| Child | 17320422 | US |
