Patent Grant
12082485
The present invention relates to novel ligands for metal complexes 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 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. 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.
This invention discloses novel ligands for metal complexes that are useful as a phosphorescent emitter in organic light emitting device. Applicant believes that incorporation of the new side chains on the ligands allow the fine tuning of emission color of the metal complex while maintaining good device efficiency and device lifetime.
According to an embodiment, a composition comprising a novel compound is disclosed, wherein the compound is capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature. The compound has at least one aromatic ring and at least one substituent R, wherein each of the at least one R is independently selected from the group consisting of partially fluorinated alkyl, partially fluorinated cycloalkyl, and combinations thereof, wherein each of the at least one R is directly bonded to one of the aromatic rings, wherein in each of the at least one R, C having an F attached thereto is separated by at least one carbon atom from the aromatic ring.
According to another embodiment, a first device comprising a first organic light emitting device is also provided. The first organic light emitting device can include an anode, a cathode, and an organic layer, disposed between the anode and the cathode. The organic layer can include the compound having at least one aromatic ring and at least one substituent R, wherein each of the at least one R is independently selected from the group consisting of partially fluorinated alkyl, partially fluorinated cycloalkyl, and combinations thereof, wherein each of the at least one R is directly bonded to one of the aromatic rings, wherein in each of the at least one R, C having an F attached thereto is separated by at least one carbon atom from the aromatic ring. The first device can be a consumer product, an organic light-emitting device, and/or a lighting panel.
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”), which 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. 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, cell phones, tablets, phablets, personal digital assistants (PDAs), laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, vehicles, a large area wall, theater or stadium screen, or 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,” “halide,” or “halogen” 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, isopropyl, butyl, isobutyl, tert-butyl, 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 7 carbon atoms and includes cyclopropyl, cyclopentyl, cyclohexyl, 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 “arylalkyl” 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 or 7 ring atoms which includes at least one hetero atom, and includes cyclic amines such as morpholino, piperdino, 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. 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 three heteroatoms, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine and pyrimidine, and the like. 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. Additionally, the heteroaryl group may be optionally substituted.
The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group, aryl, and heteroaryl may be optionally substituted with one or more substituents selected from the group consisting of hydrogen, 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 R1 is mono-substituted, then one R1 must be other than H. Similarly, where R1 is di-substituted, then two of R1 must be other than H. Similarly, where R1 is unsubstituted, R1 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.
According to an embodiment, a composition comprising a first compound is disclosed, wherein the first compound is capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature. The first compound has at least one aromatic ring and at least one substituent R, wherein each of the at least one R is independently selected from the group consisting of partially fluorinated alkyl, partially fluorinated cycloalkyl, and combinations thereof. Each of the at least one R is directly bonded to one of the aromatic rings. In each of the at least one R, a C having an F attached thereto is separated by at least one carbon atom from the aromatic ring. The first compound has the formula of M(L1)x(L2)y(L3)z; wherein M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Au, and Cu; wherein x is 1, 2, or 3; wherein y is 0, 1, or 2; wherein z is 0, 1, or 2; wherein x+y+z is the oxidation state of the metal M; wherein when L1, L2, and L3 are all present, at least one of L1, L2, and L3 is different from the others; wherein L1, L2, and L3 are each independently selected from the group consisting of:
wherein each X1 to X13 are independently selected from the group consisting of carbon and nitrogen; wherein 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″; wherein R′ and R″ are optionally fused or joined to form a ring; wherein each Ra, Rb, Rc, and Rd represents from a mono substitution to a maximum possible number of substitutions, or no substitutions; wherein each of R′, R″, Ra, Rb, Rc, and Rd 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, wherein any two adjacent substituents of Ra, Rb, Rc, and Rd are optionally fused or joined to form a ring or form a multidentate ligand; and wherein at least one Rc comprises at least one R. When one or both of L2 and L3 are present, L2 and L3 each can independently be
wherein Ra, Rb, and Rd are as defined above.
In some embodiments of the composition, X is selected from the group consisting of NR′, O, S, Se, CR′R″, and SiR′R″.
In some embodiments of the composition, each of R′, R″, Ra, Rb, Rc, and Rd 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 composition, the first compound has the formula of Ir(L1)2(L2). In some embodiments, L has the formula selected from the group AA consisting of
and wherein L2 has the formula:
In some embodiments, L2 has the formula:
wherein Re, Rf, Rh, and Ri are independently selected from group consisting of alkyl, cycloalkyl, aryl, and heteroaryl; wherein at least one of Re, Rf, Rh, and Ri has at least two carbon atoms; and wherein Rg is selected from 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, L1 and L2 are different and each of L1 and L2 is independently selected from the group AB consisting of
In some embodiments where L1 and L2 are different and each of L1 and L2 is independently selected from the group AB, at least one Rc is R.
In some embodiments, L1 and L2 in formula Ir(L1)2(L2) are each independently selected from the group consisting of:
In some embodiments, at least one Rc is R.
In some embodiments of the composition, the first compound has the formula of Pt(L1)2 or Pt(L1)(L2). In some embodiments, L1 can be connected to the other L1 or L2 to form a tetradentate ligand.
In some embodiments of the composition, at least one of Ra, Rb, Rc, and Rd includes an alkyl or cycloalkyl group that includes CD, CD2, or CD3, wherein D is a deuterium.
In some embodiments of the composition, the C having an F attached thereto is separated by at least two carbon atoms from the aromatic ring. In some embodiments, the C having an F attached thereto is separated by at least three carbon atoms from the aromatic ring. In some embodiments, the C having an F attached thereto is separated by at least one CD2 group from the aromatic ring, wherein D is a deuterium.
In some embodiments of the composition, each of the at least one R contains at least one CF3 group.
In some embodiments of the composition wherein L1 has the formula selected from the group AA, and L2 has the formula
wherein Re, Rf, Rh, and Ri are as defined above, at least one Rc is R.
In some embodiments of the composition, at least one of L1, L2, and L3 is a ligand LA, wherein LA is selected from the group AC consisting of:
and wherein RA1 through RA43 have the formulas:
In some embodiments of the composition, wherein at least one of L1, L2, and L3 is a ligand LA selected from the group AC, the first compound is selected from the group consisting of:
and wherein LBk has the following structures:
An organic light emitting device (OLED) is disclosed where the OLED comprises an anode, a cathode, and an organic layer, disposed between the anode and the cathode. The organic layer comprises a first compound, where the first compound is capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature. The first compound has at least one aromatic ring and at least one substituent R. Each of the at least one R is independently selected from the group consisting of partially fluorinated alkyl, partially fluorinated cycloalkyl, and combinations thereof. Each of the at least one R is directly bonded to one of the aromatic rings. In each of the at least one R, a C having an F attached thereto is separated by at least one carbon atom from the aromatic ring. The first compound has the formula of M(L1)x(L2)y(L3)z; wherein M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Au, and Cu; wherein x is 1, 2, or 3; wherein y is 0, 1, or 2; wherein z is 0, 1, or 2; wherein x+y+z is the oxidation state of the metal M; wherein when L1, L2, and L3 are each present, at least one of L1, L2, and L3 is different from the others; wherein L1, L2, and L3 are each independently selected from the group consisting of:
wherein each X1 to X13 are independently selected from the group consisting of carbon and nitrogen; wherein 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″; wherein R′ and R″ are optionally fused or joined to form a ring; wherein each Ra, Rb, Rc, and Rd represents from a mono substitution to a maximum possible number of substitutions, or no substitutions; wherein each of R′, R″, Ra, Rb, Rc, and Rd 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, wherein any two adjacent substituents of Ra, Rb, Rc, and Rd are optionally fused or joined to form a ring or form a multidentate ligand; and wherein at least one Rc comprises at least one R. Wherein when one or both of L2 or L3 are present, L2 or L3 each can independently be
wherein Ra, Rb, and Rd are as defined above.
In some embodiments of the OLED, X is selected from the group consisting of NR′, O, S, Se, CR′R″, and SiR′R″. In some embodiments, each of R′, R″, Ra, Rb, Rc, and Ra 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 is an emissive layer and the first compound is an emissive dopant or a non-emissive dopant. In some embodiments of the OLED, the organic layer further comprises a host, wherein the host comprises at least one selected from the group consisting of triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene. In some embodiments of the OLED, the host is a metal complex.
In some embodiments of the OLED, the 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≡C—CnH2n+1, Ar1, Ar1-Ar2, and CnH2n-Ar1, or the host has no substitutions; and wherein n is from 1 to 10; and wherein Ar1 and Ar2 are independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.
In some embodiments of the OLED, the host material is selected from the group consisting of:
and combinations thereof.
According to another aspect, consumer product comprising the OLED is also disclosed.
All reactions were carried out under nitrogen protections unless specified otherwise. All solvents for reactions are anhydrous and used as received from commercial sources.
2-amino-6-(trifluoromethyl)benzoic acid (20 g, 97 mmol) was dissolved in tetrahydrofuran (120 mL) in a 3-neck RB flask equipped with an addition funnel and a condenser. The solution was cooled in an ice-water bath. LiAlH4 (83 mL, 166 mmol) (2M solution in THF) was then added dropwise. After all of the LiAlH4 solution was added, the reaction mixture was allowed to warm to room temperature and stirred at room temperature overnight. The reaction was then quenched by adding 10 mL of Water, then 10 mL of 15% NaOH and then 25 mL of Water. The salts were filtered off and the solvents were evaporated under vacuum. The product was used as is (18 g, 97% yield).
A mixture of (2-amino-6-(trifluoromethyl)phenyl)methanol (18 g, 94 mmol), 1-(3,5-dimethylphenyl)ethanone (19.5 ml, 130 mmol), powdered potassium hydroxide (0.90 g, 16.0 mmol), and RuCl2(PPh3)3(0.45 g, 0.47 mmol) in toluene (310 ml) was refluxed overnight. Upon cooling to room temperature, the mixture was washed with water and extracted with ethyl acetate (3 times). The crude material was coated on celite and purified by CC starting with 5% EA in Heptanes. The product obtained was recrystallized from methanol to afford 2-(3,5-dimethylphenyl)-5-(trifluoromethyl)quinoline (10 g, 35% yield) as yellow crystals.
2-(3,5-dimethylphenyl)-5-(trifluoromethyl)quinoline (3.00 g, 9.96 mmol) was solubilized in ethoxyethanol (30 mL) and water (10 mL) and degassed with nitrogen for 30 minutes. Iridium chloride (0.92 g, 2.49 mmol) was then added to the solution and the reaction was refluxed under nitrogen for 24 hours. After cooling down to room temperature, the solid was filtered, washed with methanol and dried to give Ir(III) Dimer (1.0 g, 49% yield) as a brown powder.
The Ir(III) Dimer (1.08 g, 0.65 mmol) and 3,7-diethylnonane-4,6-dione (1.38 g, 6.52 mmol) were diluted in ethoxyethanol (22 mL) and the mixture was degassed by bubbling nitrogen gas for 15 minutes. K2CO3 (0.90 g, 6.52 mmol) was then added and the reaction was stirred at room temperature overnight. The mixture was diluted with dichloromethane (“DCM”), filtered through a pad of Celite, and washed with DCM. The crude material was purified by column chromatography (silica pre-treated with triethylamine (TEA)) using Heptanes/DCM 80/20 solvent system. The collected pure fractions were triturated from methanol and the solids were recrystallized from dichloromethane/methanol to afford the Comparative Compound 1 (0.85 g, 65% yield) as a dark red powder.
5-bromo-2-(3,5-dimethylphenyl)quinoline (1.15 g, 3.68 mmol), Palladium(II) acetate (0.017 g, 0.074 mmol), and CPhos (0.064 g, 0.147 mmol) were charged into a flask and diluted with 100 mL of tetrahydrofuran. This mixture was degassed with nitrogen followed by the addition of (3,3,3-trifluoropropyl)zinc(II) iodide (1.07 g, 3.68 mmol) via syringe. The reaction mixture was stirred at room temperature overnight. The reaction mixture was quenched with aqueous ammonium chloride then was extracted 2×200 mL of ethyl acetate, and dried over sodium sulfate. The crude material was coated on Celite and purified by column chromatography using a 20% DCM in Heptanes solvent system. The product was recrystallized in heptanes to afford 0.90 g of the target compound (81% yield).
2-(3,5-dimethylphenyl)-5-(3,3,3-trifluoropropyl)quinoline (1.80 g, 5.47 mmol) was solubilized in ethoxyethanol (15 mL) and Water (5 mL) and degassed with nitrogen for 30 minutes. Iridium Chloride (0.54 g, 1.46 mmol) was then added to the solution and the reaction was refluxed under nitrogen for 24 hours. After cooling down to room temperature, the solid was filtered, washed with methanol and dried to give Ir(III) Dimer (0.95 g, 74% yield) as a brown powder.
The Ir(III) Dimer (0.95 g, 0.537 mmol) and 3,7-diethylnonane-4,6-dione (1.14 g, 5.37 mmol) were diluted in ethoxyethanol (15 mL) and the mixture was degassed by bubbling nitrogen gas for 15 minutes. K2CO3 (0.74 g, 5.37 mmol) was then added and the reaction was stirred at room temperature overnight. The mixture was diluted with DCM, filtered through a pad of Celite, and washed with DCM. The crude material was purified by column chromatography (silica pre-treated with TEA) using Heptanes/DCM (100/0 to 97/3) solvent system. The collected pure fractions were triturated from methanol and the solids were recrystallized from dichloromethane/methanol to afford Compound 453 (0.83 g, 73% yield) as a dark red powder.
8-(5-chloroquinolin-2-yl)-2,6-dimethylbenzofuro[2,3-b]pyridine (3.40 g, 9.48 mmol), 2′-(dicyclohexylphosphino)-N2,N2,N6,N6-tetramethyl-[1,1′-biphenyl]-2,6-diamine (0.33 g, 0.76 mmol) and diacetoxypalladium (0.09 g, 0.38 mmol) were charged into a flask and diluted with THF (150 mL). This mixture was degassed by bubbling nitrogen followed by the addition of (3,3,3-trifluoropropyl)zinc(II) iodide (40 mL, 11.8 mmol) via syringe. This mixture was stirred at room temperature overnight. Upon completion of the reaction, it was quenched with aqueous ammonium chloride then was extracted two times with 200 mL ethyl acetate. These extracts were dried over magnesium sulfate then were filtered and concentrated under vacuum. The crude residue was purified by column chromatography using 20/80 Ethyl Acetate/Heptanes. The combined fractions were triturated in Heptanes to afford 2,6-dimethyl-8-(5-(3,3,3-trifluoropropyl)quinolin-2-yl)benzofuro[2,3-b]pyridine (2.55 g, 64% yield) as an off-white powder.
2,6-dimethyl-8-(5-(3,3,3-trifluoropropyl)quinolin-2-yl)benzofuro[2,3-b]pyridine (2.55 g, 6.07 mmol) was solubilized in 2-ethoxyethanol (19 mL) and water (6 mL) and degassed by bubbling nitrogen for 30 minutes. Iridium Chloride (0.56 g, 1.52 mmol) was then added to the solution (some ligand had precipitated) and the reaction was refluxed under nitrogen for 24 hours. After cooling down to room temperature, the solid was filtered, washed with methanol and dried to give Ir(III) Dimer (1.10 g, 68% yield) as a red powder.
The Ir(III) Dimer (1.00 g, 0.47 mmol) and 3,7-diethylnonane-4,6-dione (0.91 g, 4.26 mmol) were diluted in 2-Ethoxyethanol (14 mL) and the mixture was degassed by bubbling nitrogen gas for 15 minutes. K2CO3 (0.59 g, 4.26 mmol) was then added and the reaction was stirred at room temperature overnight. The mixture was diluted with dichloromethane, filtered through a pad of Celite, and washed with DCM. The crude material was purified by column chromatography (silica pre-treated with TEA) using Heptanes/dichloromethane 80/20 solvent system. The combined fractions were triturated from methanol and the solids were recrystallized from dichloromethane/methanol once. The title product was obtained as a red powder (0.8 g, 76% yield).
5-bromo-2-fluoro-1,3-dimethylbenzene (20 g, 100 mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (51 g, 200 mmol), Pd2(dba)3 (1.83 g, 2.00 mmol), dicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine (SPhos) (3.28 g, 8.00 mmol), potassium acetate (24.5 g, 250 mmol) and dioxane (600 mL) were combined in a three neck round bottom flask. A condenser was attached then the system was evacuated and purged with nitrogen three times. The reaction was heated to reflux overnight. Upon completion, the reaction was filtered through celite and washed with ethyl acetate. The filtrate was concentrated down to a dark red oil which was dissolved in 400 mL heptane and loaded on to a silica gel plug in a sintered filter funnel. The silica gel was washed with 2 L heptane portion then one 1 L of 98/2 heptane/ethyl acetate to recover most of the product and remove the bispinocolate. These portions were combined and concentrated down to 30 g of yellow oil which was purified with silica gel using heptane to 95/5 heptane/ethyl acetate solvent system. Fractions containing the desired product were combined and concentrated down to 17.5 g of a light yellow solid for a 70% yield.
4,7-dichloroquinazoline (4.0 g, 20.1 mmol), 2-(4-fluoro-3,5-dimethylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (5.53 g, 22.1 mmol), sodium carbonate (5.33 g, 50.2 mmol), palladium tetrakis (0.70 g, 0.60 mmol), dimethoxyethane (“DME”) (160 mL), and water (40 mL) were combined in a three neck round bottom flask. A condenser was attached then the system was evacuated and purged with nitrogen three times. The reaction was heated to a vigorous reflux overnight. The reaction was diluted with ethyl acetate, water and brine. The aqueous was partitioned off and the organic was washed once with brine, dried with sodium sulfate, filtered then concentrated down to a yellow solid. The yellow solid was purified with silica gel using DCM to 85/15 DCM/ethyl acetate solvent system to get 4.1 g of light yellow solid for a 710% yield.
7-chloro-4-(4-fluoro-3,5-dimethylphenyl)quinazoline (2.75 g, 9.59 mmol),2′-(dicyclohexylphosphino)-N2,N2,N6,N6-tetramethyl-[1,1′-biphenyl]-2,6-diamine (CPhos) (0.34 g, 0.77 mmol), and diacetoxypalladium (0.090 g, 0.38 mmol) and 100 mL anhydrous THF were placed in an oven dried three neck round bottom flask. The system was evacuated and purged with nitrogen three times. (3,3,3-trifluoropropyl)zinc(II) iodide (86 ml, 19.2 mmol) was added via syringe. Upon completion of the reaction, it was quenched with ammonium chloride solution then transferred to a separatory funnel with ethyl acetate. The aqueous was partitioned off, then the organics were washed once with brine, dried with sodium sulfate, filtered and concentrated down. The crude solid was purified with silica gel using DCM to 90/10 DCM/ethyl acetate solvent system to get 3.3 g of a brownish-red solid. The 3.3 g solid was purified using C18 cartridges using 80/20 to 85/15 acetonitrile/water solvent system. The combined fractions were concentrated down then dried in the vacuum oven overnight to get 2.36 g of a white solid for a 710% yield.
4-(4-fluoro-3,5-dimethylphenyl)-7-(3,3,3-trifluoropropyl)quinazoline (2.56 g, 7.34 mmol) was inserted in a RBF and was solubilized in ethoxythanol (23 mL) and water (8 mL). The mixture was degassed by bubbling nitrogen gas for 15 minutes and then iridium chloride (0.68 g, 1.84 mmol) was inserted and the reaction was heated at 105° C. for 24 hours. The reaction was cooled down to room temperature, diluted with 10 mL of MeOH, filtered and washed with MeOH. The Ir(III) Dimer (1.50 g, 89% yield) was afforded as an orange powder.
The dimer (1.50 g, 0.81 mmol), 3,7-diethylnonane-4,6-dione (1.73 g, 8.13 mmol), and 2-ethoxyethanol (50 ml) were combined in a round bottom flask. Nitrogen was bubbled directly into the suspension for 15 min. Potassium carbonate (1.12 g, 8.13 mmol) was added and the reaction was run at room temperature overnight. Upon completion, the reaction was filtered through celite and washed with DCM until the red color came off. The solution was concentrated down to a dark red oily solid, taken up in DCM and adsorbed on to celite. The sample was purified with silica gel to give 0.24 g of dark red solid with 13% yield.
Lithium chloride (1.87 g, 44.1 mmol) was charged into a reaction flask. The flask was evacuated and heated using a heat gun for 10 minutes. The flask was cooled down to room temperature and zinc (2.88 g, 44.1 mmol) was added to the flask. The flask was again evacuated and heated using a heat gun for 10 minutes. The flask was cooled to room temperature and THF (80 mL) was added via syringe into the reaction followed by 1,2-dibromoethane (0.42 mL, 4.90 mmol). This mixture was stirred for 30 minutes in an oil bath set at 60° C. The mixture was cooled to room temperature followed by the addition of chlorotrimethylsilane (0.12 ml, 0.98 mmol) and iodine (0.25 g, 0.98 mmol) dissolved in 4 mL of THF. The mixture was again stirred for 30 minutes in an oil bath set at 60° C. and cooled to room temperature. 1,1,1-Trifluoro-4-iodo-2-(trifluoromethyl)butane (7.50 g, 24.5 mmol) was then injected into the reaction mixture via syringe. The heterogeneous reaction mixture was stirred and heated in an oil bath set at 50° C. overnight. The reaction mixture was cooled to room temperature and the product was used without further purification.
8-(5-Chloroquinolin-2-yl)-2,6-dimethylbenzofuro[2,3-b]pyridine (3.40 g, 9.48 mmol), 2′-(dicyclohexylphosphino)-N2,N2,N6,N6-tetramethyl-[1,1′-biphenyl]-2,6-diamine (CPhos) (0.33 g, 0.76 mmol) and diacetoxypalladium (0.09 g, 0.38 mmol) were dissolved in THF (190 mL). This mixture was degassed by bubbling nitrogen for 15 minutes followed by the addition of (3,3,3-trifluoropropyl)zinc(II) iodide (35 mL, 10.4 mmol) via syringe. This mixture was stirred at room temperature overnight. Upon completion of the reaction, the mixture was quenched with aqueous ammonium chloride then it was extracted with 2×200 mL ethyl acetate. These extracts were dried over magnesium sulfate, filtered and concentrated under vacuum. The crude material was purified by column chromatography using heptanes/ethyl acetate (95/5 to 90/10 gradient mixture). The product was triturated with methanol and then recrystallized from heptanes to afford 2-(3,5-dimethylphenyl)-5-(4,4,4-trifluoro-3-(trifluoromethyl)butyl)quinoline (2.5 g, 51% yield) as a white solid.
2-(3,5-dimethylphenyl)-5-(4,4,4-trifluoro-3-(trifluoromethyl)butyl)quinoline (2.48 g, 6.02 mmol) was dissolved in ethoxythanol (24 mL) and water (8 mL). The mixture was degassed by bubbling nitrogen gas for 15 minutes and then Iridium chloride (0.72 g, 1.94 mmol) was added and the reaction was heated at 105° C. for 24 hours. The reaction was cooled down to room temperature, diluted with 10 mL of MeOH, filtered and washed with MeOH to afford the Ir(III) Dimer (1.2 g, 59% yield)
The Ir(III) dimer (0.50 g, 0.24 mmol) was solubilized in Ethoxyethanol (8 mL) and pentane-2,4-dione (0.25 mL, 2.39 mmol) was added. The mixture was degassed by bubbling nitrogen gas for 15 minutes and K2CO3 (0.33 g, 2.39 mmol) was then added. The reaction was stirred at room temperature overnight. Upon completion of the reaction, the mixture was diluted with DCM, filtered through celite and washed with DCM. The crude product was coated on Celite and purified by column chromatography (TEA pretreated) using heptanes/DCM (95/5) solvent system. The product was recrystallized 5 times from MeOH/DCM, EtOH/DCM, and THF/i-PrOH to afford 0.18 g (34% yield) of the target compound.
The Ir(III) dimer (0.70 g, 0.33 mmol) was solubilized in ethoxyethanol (15 mL) and 3,7-diethylnonane-4,6-dione (0.71 g, 3.34 mmol) was added. The mixture was degassed by bubbling nitrogen gas for 15 minutes and K2CO3 (0.46 g, 3.34 mmol) was then added and the reaction was stirred at room temperature overnight. Upon completion of the reaction, the mixture was diluted with DCM, filtered through celite and washed with DCM. The crude product was coated on Celite and purified by column chromatography (TEA pretreated silica gel) eluting with heptanes/DCM (95/5 to 90/10 gradient mixture) solvent system. The product was triturated from methanol to afford 0.21 g (26% yield) of the dopant.
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.
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 not limit 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. Wherein each Ar is further substituted by a substituent 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 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 not limit 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.
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. While the Table below categorizes host materials as preferred for devices that emit various colors, 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 organic compounds used as host are 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. Wherein each group is further substituted by a substituent 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 one aspect, the host compound contains at least one of the following groups in the molecule:
wherein R101 to R107 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, 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; k′″ is an integer from 0 to 20.
X101 to X108 is selected from C (including CH) or N.
Z101 and Z102 is selected from NR101, O, or S.
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 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 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.
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. encompasses undeuterated, partially deuterated, and fully deuterated versions thereof. Similarly, classes of substituents such as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc. also encompass undeuterated, partially deuterated, and fully deuterated versions thereof.
In addition to and/or in combination with the materials disclosed herein, many hole injection materials, hole transporting materials, host materials, dopant materials, exiton/hole blocking layer materials, electron transporting and electron injecting materials may be used in an OLED. Non-limiting examples of the materials that may be used in an OLED in combination with materials disclosed herein are listed in Table A below. Table A lists non-limiting classes of materials, non-limiting examples of compounds for each class, and references that disclose the materials.
All example devices were fabricated by high vacuum (<10−7 Torr) thermal evaporation. The anode electrode was 1200 Å of indium tin oxide (ITO). The cathode consisted of 10 Å of LiF 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, and a moisture getter was incorporated inside the package. The organic stack of the device examples consisted of sequentially, from the ITO surface, 100 Å of LG 101 (purchased from LG chem) as the hole injection layer (HIL); 400 Å of 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD) as the hole transporting layer (HTL); 300 Å of an emissive layer (EML) containing Compound H as a host (790%), a stability dopant (SD) (18%), and Compound 453, Compound 781, or Compound 699 as an emitter; 100 Å of Compound H as a blocking layer; and 450 Å of Alq3 (tris-8-hydroxyquinoline aluminum) as the ETL. The emitter was selected to provide the desired color and the stability dopant (SD) was mixed with the electron-transporting host and the emitter to help transport positive charge in the emissive layer. The Comparative Example device was fabricated similarly to the device examples except that Comparative Compound 1 was used as the emitter in the EML. Table 1 shows the composition of the EML in the device, while the device results and data are summarized in Table 2. As used herein, NPD, compound H, SD, and AlQ3 have the following structures:
Comparative Compound 1 used in the experiments has the following structure
Representative inventive compounds Compound 453, Compound 781, Compound 699, Compound 22, and Compound 473 used in the experiments have the following structures:
Table 1 below lists the compounds used as the emitter dopants in the EML layer of the experimental devices.
Table 2 below provides the device performance data for Inventive Device Examples 1, 2, 3, 4 and 5 and Comparative Device example 1.
Table 2 summarizes the performance of the experimental devices. The 1931 CIE values were measured at 10 mA/cm2. The luminous efficiency was measured at 1000 cd/m2. The EQE, and LT95% of comparative example 1 were set at a value of 1.00. The values obtained from the inventive examples are relative to that of the comparative example. All of the Inventive Device Examples exhibit higher external quantum efficiencies (EQE) than the Comparative example 1 (1.74, 1.74, 1.82, 1.64, 1.80 vs. 1.00). The lifetime represented by LT95% at 1,000 nits of the inventive compounds Compound 453, 781, 699, 22, and 473 (Inventive Device Examples 1, 2, 3, 4, and 5) were also more stable than that of the Comparative Compound 1 (Comparative example 1) (8.55, 9.09, 5.73, 1.53, 1.54 vs. 1.00).
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 of U.S. patent application Ser. No. 17/018,406, filed Sep. 11, 2020, which is a continuation of U.S. patent application Ser. No. 15/911,418, filed Mar. 5, 2018, now U.S. Pat. No. 10,854,826, which is a continuation-in-part of U.S. patent application Ser. No. 15/684,307, filed on Aug. 23, 2017, now U.S. Pat. No. 10,998,508, which is a continuation of U.S. patent application Ser. No. 15/177,906, filed on Jun. 9, 2016, now U.S. Pat. No. 9,799,838, issued on Oct. 24, 2017, which is a continuation of U.S. patent application Ser. No. 14/509,274, filed on Oct. 8, 2014, now U.S. Pat. No. 9,397,302, issued on Jul. 19, 2016.
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