Organic electroluminescent materials and devices

Abstract

A luminescent compound that is a metal complex with ligands containing pyrrole or indole in the structure, where the pyrrole or indole has an aromatic substituent that has at least one ortho substitution is disclosed.

Claims

1. A compound selected from the group consisting of: ##STR00286## ##STR00287## ##STR00288## ##STR00289## ##STR00290## ##STR00291## ##STR00292## ##STR00293## ##STR00294## ##STR00295## ##STR00296## ##STR00297## ##STR00298## ##STR00299## ##STR00300## ##STR00301## ##STR00302## ##STR00303## ##STR00304## ##STR00305## ##STR00306## ##STR00307## ##STR00308##

2. A first device comprising a first organic light emitting device, the first organic light emitting device comprising: an anode; a cathode; and an organic layer, disposed between the anode and the cathode, comprising a compound selected from the group consisting of: ##STR00309## ##STR00310## ##STR00311## ##STR00312## ##STR00313## ##STR00314## ##STR00315## ##STR00316## ##STR00317## ##STR00318## ##STR00319## ##STR00320## ##STR00321## ##STR00322## ##STR00323## ##STR00324## ##STR00325## ##STR00326## ##STR00327## ##STR00328## ##STR00329## ##STR00330## ##STR00331##

3. A formulation comprising the compound selected from the group consisting of: ##STR00332## ##STR00333## ##STR00334## ##STR00335## ##STR00336## ##STR00337## ##STR00338## ##STR00339## ##STR00340## ##STR00341## ##STR00342## ##STR00343## ##STR00344## ##STR00345## ##STR00346## ##STR00347## ##STR00348## ##STR00349## ##STR00350## ##STR00351## ##STR00352## ##STR00353## ##STR00354## ##STR00355## ##STR00356## ##STR00357##

4. The first device of claim 2, wherein the first device is a consumer product.

5. The first device of claim 4, wherein the consumer product is one of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads up display, a fully transparent display, a flexible display, a laser printer, a telephone, a cell phone, a personal digital assistant (PDA), a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display, a 3-D display, a vehicle, a large area wall, theater or stadium screen, or a sign.

6. The first device of claim 2, wherein the organic layer is an emissive layer and the compound is an emissive dopant.

7. The first device of claim 2, wherein the organic layer is an emissive layer and the compound is a non-emissive dopant.

8. The first device of claim 2, wherein the organic layer further comprises a host.

9. The first device of claim 8, wherein 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 C.sub.nH.sub.n+1, OC.sub.nH.sub.n+1, OAr.sub.1, N(C.sub.nH.sub.n+1).sub.2, N(Ar.sub.1)(Ar.sub.2), CHCHC.sub.nH.sub.n+1, CCC.sub.nH.sub.2n+1, Ar.sub.1, Ar.sub.1Ar.sub.2, and C.sub.nH.sub.2nAr.sub.1, or the host has no substitution; wherein n is from 1 to 10; and wherein Ar.sub.1 and Ar.sub.2 are independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.

10. The first device of claim 8, wherein the host comprises at least one chemical group selected from the group consisting of carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

11. The first device of claim 8, wherein the host is selected from the group consisting of: ##STR00358## ##STR00359## ##STR00360## and combinations thereof.

12. The first device of claim 8, wherein the host comprises a metal complex.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an organic light emitting device that can incorporate the inventive host material disclosed herein.

(2) FIG. 2 shows an inverted organic light emitting device that can incorporate the inventive host material disclosed herein.

(3) FIG. 3 shows Formula 1 as disclosed herein.

DETAILED DESCRIPTION

(4) 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.

(5) 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.

(6) 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.

(7) FIG. 1 shows an organic light emitting device 100. The figures are not necessarily drawn to scale. Device 100 may include a substrate 110, an anode 115, a hole injection layer 120, a hole transport layer 125, an electron blocking layer 130, an emissive layer 135, a hole blocking layer 140, an electron transport layer 145, an electron injection layer 150, a protective layer 155, a cathode 160, and a barrier layer 170. Cathode 160 is a compound cathode having a first conductive layer 162 and a second conductive layer 164. Device 100 may be fabricated by depositing the layers described, in order. The properties and functions of these various layers, as well as example materials, are described in more detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which are incorporated by reference.

(8) 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 F.sub.4-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 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.

(9) FIG. 2 shows an inverted OLED 200. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole transport layer 225, and an anode 230. Device 200 may be fabricated by depositing the layers described, in order. Because the most common OLED configuration has a cathode disposed over the anode, and device 200 has cathode 215 disposed under anode 230, device 200 may be referred to as an inverted OLED. Materials similar to those described with respect to device 100 may be used in the corresponding layers of device 200. FIG. 2 provides one example of how some layers may be omitted from the structure of device 100.

(10) The simple layered structure illustrated in FIGS. 1 and 2 is provided by way of non-limiting example, and it is understood that embodiments of the invention may be used in connection with a wide variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures may be used. Functional OLEDs may be achieved by combining the various layers described in different ways, or layers may be omitted entirely, based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many of the examples provided herein describe various layers as comprising a single material, it is understood that combinations of materials, such as a mixture of host and dopant, or more generally a mixture, may be used. Also, the layers may have various sublayers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 225 transports holes and injects holes into emissive layer 220, and may be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an organic layer disposed between a cathode and an anode. This organic layer may comprise a single layer, or may further comprise multiple layers of different organic materials as described, for example, with respect to FIGS. 1 and 2.

(11) 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 FIGS. 1 and 2. For example, the substrate may include an angled reflective surface to improve out-coupling, such as a mesa structure as described in U.S. Pat. No. 6,091,195 to Forrest et al., and/or a pit structure as described in U.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated by reference in their entireties.

(12) 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.

(13) 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.

(14) Devices fabricated in accordance with embodiments of the invention may be incorporated into a wide variety of consumer products, including flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads up displays, fully transparent displays, flexible displays, laser printers, telephones, cell phones, 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.

(15) 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.

(16) The term halo or halogen as used herein includes fluorine, chlorine, bromine, and iodine.

(17) 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.

(18) 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.

(19) 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.

(20) 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.

(21) 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.

(22) The term heterocyclic group as used herein contemplates aromatic and non-aromatic cyclic radicals. Hetero-aromatic cyclic radicals also refer to 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.

(23) 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.

(24) 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.

(25) 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.

(26) 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.sup.1 is mono-substituted, then one R.sup.1 must be other than H. Similarly, where R.sup.1 is di-substituted, then two of R.sup.1 must be other than H. Similarly, where R.sup.1 is unsubstituted, R.sup.1 is hydrogen for all available positions.

(27) The aza designation in the fragments described herein, i.e. aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more of the CH 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.

(28) 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.

(29) As used herein, the phrase electron acceptor or acceptor means a fragment that can accept electron density from an aromatic system, and the phrase electron donor or donor means a fragment that donates electron density into an aromatic system.

(30) The present disclosure discloses metal complexes with ligands containing pyrrole or indole in the structure that are useful as emitters in phosphorescent OLEDs. The pyrrole or indole has an aromatic substituent that has at least one ortho substitution.

(31) According to an embodiment, a compound comprising a first ligand L.sup.1 having a structure according to Formula I shown below is disclosed.

(32) ##STR00003##
In Formula I, ring A and ring B are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;
wherein X is a neutral donor selected from the group consisting of N, C, and P; R.sup.A and R.sup.B each independently represent mono, di, tri, or tetra substitution, or no substitution;
R.sup.A, R.sup.B, R.sup.C, and R.sup.D are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;
R is selected from the group consisting of halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;
any two adjacent substituents are optionally joined to form a ring, which can be further substituted;
the ligand L.sup.1 is coordinated to a metal M;
the metal M can be coordinated to other ligands; and
the ligand L.sup.1 is optionally linked with other ligands to comprise a tridentate, tetradentate, pentadentate or hexadentate ligand.

(33) In one embodiment, M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Au, and Cu. In another embodiment, M is Ir or Pt.

(34) In one embodiment, the ligand L.sup.1 is selected from the group consisting of:

(35) ##STR00004##
wherein R.sup.N is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

(36) In one embodiment, the ring B is phenyl. In another embodiment, the ring B is a six-membered aryl or heteroaryl having substitutions on both ortho positions.

(37) In one embodiment, the compound is homoleptic. In another embodiment, the compound is heteroleptic.

(38) In one embodiment of the compound, R is selected from the group consisting of halogen, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof. In another embodiment, R is selected from the group consisting of 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, cyclopentyl, cyclohexyl, phenyl, 2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-diisopropylphenyl, and combinations thereof.

(39) In one embodiment, the compound has a neutral charge.

(40) In one embodiment of the compound, the ligand L.sup.1 is selected from the group consisting of:

(41) ##STR00005## ##STR00006## ##STR00007## ##STR00008## ##STR00009## ##STR00010## ##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016## ##STR00017## ##STR00018## ##STR00019## ##STR00020## ##STR00021## ##STR00022## ##STR00023## ##STR00024## ##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030## ##STR00031## ##STR00032## ##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044## ##STR00045## ##STR00046## ##STR00047## ##STR00048## ##STR00049## ##STR00050## ##STR00051## ##STR00052## ##STR00053## ##STR00054## ##STR00055## ##STR00056## ##STR00057## ##STR00058## ##STR00059## ##STR00060##

(42) In another embodiment, the compound has a structure according to formula of M(L.sup.1).sub.x(L.sup.2).sub.y(L.sup.3).sub.z; wherein L.sup.2 is a second ligand, and L.sup.3 is a third ligand, and L.sup.2 and L.sup.3 can be the same or different; 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 the second ligand L.sup.2 and the third ligand L.sup.3 are independently selected from the group consisting of:

(43) ##STR00061## ##STR00062## ##STR00063##

(44) wherein R.sub.a, R.sub.b, R.sub.c, and R.sub.d may represent mono, di, tri, or tetra substitution, or no substitution;

(45) wherein R.sub.a, R.sub.b, R.sub.c, and R.sub.d are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

(46) wherein two adjacent substituents of R.sub.a, R.sub.b, R.sub.c, and R.sub.d are optionally joined to form a fused ring or form a multidentate ligand.

(47) In another embodiment, the compound has a structure according to the formula of Ir(L.sup.1).sub.2(L.sup.2), where L.sup.1 and L.sup.2 are as defined above. In another embodiment of the compound having the structure according to the formula Ir(L.sup.1).sub.2(L.sup.2), L.sup.2 has a structure according to the formula:

(48) ##STR00064##
wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently selected from group consisting of alkyl, cycloalkyl, aryl, and heteroaryl;

(49) wherein at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 has at least two carbon atoms;

(50) wherein R.sup.5 is selected from group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

(51) According to an embodiment, the compound having a structure according to the formula M(L.sup.1).sub.x(L.sup.2).sub.y(L.sup.3).sub.z has a structure according to the formula of Pt(L.sup.1).sub.2 or Pt(L.sup.1)(L.sup.2), where L.sup.1 and L.sup.2 are as defined above. In another embodiment of the compound having the structure according to the formula Pt(L.sup.1).sub.2 or Pt(L.sup.1)(L.sup.2), L.sup.1 can be connected to the L.sup.2 or the other L.sup.1 to form a tetradentate ligand.

(52) According to an embodiment, the compound is preferably selected from the group consisting of:

(53) ##STR00065## ##STR00066## ##STR00067## ##STR00068## ##STR00069## ##STR00070## ##STR00071## ##STR00072## ##STR00073## ##STR00074## ##STR00075## ##STR00076## ##STR00077## ##STR00078## ##STR00079## ##STR00080## ##STR00081## ##STR00082## ##STR00083## ##STR00084## ##STR00085## ##STR00086## ##STR00087## ##STR00088## ##STR00089## ##STR00090##

(54) According to another aspect of the present disclosure, a first device comprising a first organic light emitting device is also disclosed. The first organic light emitting device comprises: an anode; a cathode; and an organic layer, disposed between the anode and the cathode. The organic layer comprises a compound comprising a first ligand L.sup.1 having a structure according to Formula I as defined above.

(55) In one embodiment, the first device can be a consumer product. The first device can be an organic light-emitting device. The first device can be a lighting panel.

(56) In one embodiment, the organic layer in the first device is an emissive layer and the compound is an emissive dopant.

(57) In another embodiment, the organic layer in the first device is an emissive layer and the compound is a non-emissive dopant.

(58) In another embodiment, the organic layer in the first device can further comprise a host material. The host material 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 C.sub.nH.sub.2n+1, OC.sub.nH.sub.2n+1, OAr.sub.1, N(C.sub.nH.sub.2n+1).sub.2, N(Ar.sub.1)(Ar.sub.2), CHCHC.sub.nH.sub.2n+1, CCC.sub.nH.sub.2n+1, Ar.sub.1, Ar.sub.1Ar.sub.2, C.sub.nH.sub.2nAr.sub.1, or no substitution;

(59) wherein n is from 1 to 10; and

(60) wherein Ar.sub.1 and Ar.sub.2 are independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.

(61) In one embodiment, the host material comprises at least one chemical group selected from the group consisting of carbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene. In another embodiment, the host material is selected from the group consisting of:

(62) ##STR00091## ##STR00092##
and combinations thereof.

(63) In another embodiment of the first device, the host material comprises a metal complex.

(64) According to another aspect of the present disclosure, a formulation comprising the compound comprising a first ligand L.sup.1 having a structure according to Formula I is also disclosed, wherein Formula I being as defined above. 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.

(65) Materials Synthesis

(66) All reactions were carried out under nitrogen protections unless specified otherwise. All solvents for reactions are anhydrous and used as received from commercial sources.

Synthesis of the Inventive Compound 58

Synthesis of 2-((2-chlorophenyl)ethynyl)pyridine

(67) ##STR00093##
Bis(triphenylphosphine)palladium(II) dichloride (0.99 g, 1.41 mmol), copper(I) iodide (0.54 g, 2.82 mmol), and triphenylphosphine (0.74 g, 2.82 mmol) were suspended in diisopropylamine (150 mL) in a flask. 1-Chloro-2-iodobenzene (6.15 ml, 50.3 mmol) then 2-ethynylpyridine (5.59 ml, 55.4 mmol) were added. A condenser was attached and then the system was evacuated and purged with nitrogen three times. The reaction was heated to 40 C. overnight. Upon completion, the reaction was filtered through Celite using ethyl acetate then concentrated down to a brown oil. The brown oil was taken up in ethyl acetate and washed sodium bicarbonate solution once, brine twice, dried with sodium sulfate, filtered and concentrated down to a brown oil. The sample was purified with silica gel using DCM (dichloromethane) to 97.5/2.5 DCM/ethyl acetate solvent system to get 11.3 g of a yellow oil for a quantitative yield.

Synthesis of 1-(2,6-diisopropylphenyl)-2-(pyridin-2-yl)-1H-indole

(68) ##STR00094##
To an oven dried three neck round bottom flask, palladium(II) acetate (0.58 g, 2.57 mmol), 1,3-bis(2,6-diisopropylphenyl)imidazolidine, chloride salt (1.10 g, 2.57 mmol) and dry potassium tert-butoxide (14.4 g, 130 mmol) were added. 2-((2-chlorophenyl)ethynyl)pyridine (11.0 g, 51.5 mmol) dissolved in dry toluene (220 mL), then 2,6-diisopropylaniline (10.7 ml, 56.6 mmol) were added to the reaction. The system was evacuated and purged with nitrogen three times, then heated to reflux overnight. The reaction was quenched with water then transferred to a separatory funnel with ethyl acetate. Brine was added, mixed and the aqueous layer was partitioned off. The aqueous solution was extracted with ethyl acetate twice. The combined organics were washed with brine twice, dried with sodium sulfate then concentrated down to a brown oil. The sample was purified by column chromatography to afford 1.13 g (6% yield) of the target compound.

Synthesis of Ir(III) Dimer

(69) ##STR00095##
1-(2,6-diisopropylphenyl)-2-(pyridin-2-yl)-1H-indole (1.15 g, 3.24 mmol) was solubilized in ethoxyethanol (9 mL) and water (3 mL) and degassed with nitrogen for 30 minutes. Iridium chloride (0.34 g, 0.93 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 the Ir(III) Dimer (0.33 g, 38% yield) as a red powder.

Synthesis of Compound 58

(70) ##STR00096##
The dimer (0.33 g, 0.18 mmol), 3,7-diethylnonane-4,6-dione (0.38 g, 1.77 mmol), and 2-ethoxyethanol (6 mL) were combined in a flask. Nitrogen was bubbled directly into the solution for 15 min and potassium carbonate (0.24 g, 1.77 mmol) was then added and the reaction was heated at 60 C. overnight. The reaction was filtered through Celite using DCM until all the dark red color came off. The sample was purified with silica gel, which was preconditioned with 75/20/5 heptane/triethyl amine/DCM solvent system then using 95/5 heptane/DCM solvent system. The combined fractions were concentrated down. The dark red solid was triturated in 50 mL of MeOH to afford 0.26 g (67% yield) of a dark red solid.
Combination with Other Materials

(71) 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.

(72) HIL/HTL:

(73) 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 MoO.sub.x; a p-type semiconducting organic compound, such as 1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and a cross-linkable compounds.

(74) Examples of aromatic amine derivatives used in HIL or HTL include, but not limit to the following general structures:

(75) ##STR00097##

(76) Each of Ar.sup.1 to Ar.sup.9 is selected from the group consisting aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; group consisting 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 group consisting 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.

(77) In one aspect, Ar.sup.1 to Ar.sup.9 is independently selected from the group consisting of:

(78) ##STR00098##
wherein k is an integer from 1 to 20; X.sup.101 to X.sup.108 is C (including CH) or N; Z.sup.101 is NAr.sup.1, O, or S; Ar.sup.1 has the same group defined above.

(79) Examples of metal complexes used in HIL or HTL include, but not limit to the following general formula:

(80) ##STR00099##
wherein Met is a metal, which can have an atomic weight greater than 40; (Y.sup.101Y.sup.102) is a bidentate ligand, Y.sup.101 and Y.sup.102 are independently selected from C, N, O, P, and S; L.sup.101 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.

(81) In one aspect, (Y.sup.101Y.sup.102) is a 2-phenylpyridine derivative. In another aspect, (Y.sup.101Y.sup.102) 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.sup.+/Fc couple less than about 0.6 V.

(82) Host:

(83) 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.

(84) Examples of metal complexes used as host are preferred to have the following general formula:

(85) ##STR00100##
wherein Met is a metal; (Y.sup.103Y.sup.104) is a bidentate ligand, Y.sup.103 and Y.sup.104 are independently selected from C, N, O, P, and S; L.sup.101 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.

(86) In one aspect, the metal complexes are:

(87) ##STR00101##
wherein (ON) is a bidentate ligand, having metal coordinated to atoms O and N.

(88) In another aspect, Met is selected from Ir and Pt. In a further aspect, (Y.sup.103Y.sup.104) is a carbene ligand.

(89) Examples of organic compounds used as host are selected from the group consisting aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; group consisting 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 group consisting 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.

(90) In one aspect, host compound contains at least one of the following groups in the molecule:

(91) ##STR00102## ##STR00103##
wherein R.sup.101 to R.sup.107 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. X.sup.101 to X.sup.108 is selected from C (including CH) or N.
Z.sup.101 and Z.sup.102 is selected from NR.sup.101, O, or S.
HBL:

(92) 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.

(93) In one aspect, compound used in HBL contains the same molecule or the same functional groups used as host described above.

(94) In another aspect, compound used in HBL contains at least one of the following groups in the molecule:

(95) ##STR00104##
wherein k is an integer from 1 to 20; L.sup.101 is an another ligand, k is an integer from 1 to 3.
ETL:

(96) 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.

(97) In one aspect, compound used in ETL contains at least one of the following groups in the molecule:

(98) ##STR00105##
wherein R.sup.101 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. Ar.sup.1 to Ar.sup.3 has the similar definition as Ar's mentioned above. k is an integer from 1 to 20. X.sup.101 to X.sup.108 is selected from C (including CH) or N.

(99) In another aspect, the metal complexes used in ETL contains, but not limit to the following general formula:

(100) ##STR00106##
wherein (ON) or (NN) is a bidentate ligand, having metal coordinated to atoms O, N or N, N; L.sup.101 is another ligand; k is an integer value from 1 to the maximum number of ligands that may be attached to the metal.

(101) 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.

(102) 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.

(103) TABLE-US-00001 TABLE A MATERIAL EXAMPLES OF MATERIAL PUBLICATIONS Hole injection materials Phthalocyanine and porphyrin compounds 07 Appl. Phys. Lett. 69, 2160 (1996) Starburst triarylamines 08 J. Lumin. 72-74, 985 (1997) CF.sub.x Fluoro- hydrocarbon polymer 09 Appl. Phys. Lett. 78, 673 (2001) Conducting polymers (e.g., PEDOT:PSS, polyaniline, polythiophene) 0 Synth. Met. 87, 171 (1997) WO2007002683 Phosphonic acid and silane SAMs US20030162053 Triarylamine or polythiophene polymers with conductivity dopants and EP1725079A1 Organic compounds with conductive inorganic compounds, such as molybdenum and tungsten oxides US20050123751 SID Symposium Digest, 37, 923 (2006) WO2009018009 n-type semi- conducting organic complexes US20020158242 Metal organometallic complexes US20060240279 Cross-linkable compounds US20080220265 Polythiophene based polymers and copolymers WO 2011075644 EP2350216 Hole transporting materials Triarylamines (e.g. TPD, -NPD) 0 Appl. Phys. Lett. 51, 913 (1987) US5061569 EP650955 J. Mater. Chem. 3, 319 (1993) Appl. Phys. Lett. 90, 183503(2007) Appl. Phys. Lett. 90, 183503(2007) Triarylamine on spirofluorene core Synth. Met. 91, 209 (1997) Arylamine carbazole compounds Adv. Mater. 6, 677 (1994), US20080124572 Triarylamine with (di)benzothiophene/ (di)benzofuran US20070278938, US20080106190 US20110163302 Indolocarbazoles Synth. Met. 111, 421 (2000) Isoindole compounds 0 Chem. Mater. 15, 3148 (2003) Metal carbene complexes US20080018221 Phosphorescent OLED host materials Red hosts Arylcarbazoles Appl. Phys. Lett. 78, 1622 (2001) Metal 8-hydroxyquinolates (e.g., Alq.sub.3, BAlq) Nature 395, 151 (1998) US20060202194 WO2005014551 WO2006072002 Metal phenoxy- benzothiazole compounds Appl. Phys. Lett. 90, 123509 (2007) Conjugated oligomers and polymers (e.g., polyfluorene) Org. Electron. 1, 15 (2000) Aromatic fused rings WO2009066779, WO2009066778, WO2009063833, US20090045731, US20090045730, WO2009008311, US20090008605, US20090009065 Zinc complexes 0 WO2010056066 Chrysene based compounds WO2011086863 Green hosts Arylcarbazoles Appl. Phys. Lett. 78, 1622 (2001) US20030175553 WO2001039234 Aryltriphenylene compounds US20060280965 US20060280965 WO2009021126 Poly-fused heteroaryl compounds US20090309488 US20090302743 US20100012931 Donor acceptor type molecules WO2008056746 0 WO2010107244 Aza-carbazole/ DBT/DBF JP2008074939 US20100187984 Polymers (e.g., PVK) Appl. Phys. Lett. 77, 2280 (2000) Spirofluorene compounds WO2004093207 Metal phenoxybenzo- oxazole compounds WO2005089025 WO2006132173 JP200511610 Spirofluorene- carbazole compounds JP2007254297 JP2007254297 Indolocarbazoles 0 WO2007063796 WO2007063754 5-member ring electron deficient heterocycles (e.g., triazole, oxadiazole) J. Appl. Phys. 90, 5048 (2001) WO2004107822 Tetraphenylene complexes US20050112407 Metal phenoxy- pyridine compounds WO2005030900 Metal coordination complexes (e.g., Zn, Al with N{circumflex over ()}N ligands) US20040137268, US20040137267 Blue hosts Arylcarbazoles Appl. Phys. Lett, 82, 2422 (2003) US20070190359 Dibenzothiophene/ Dibenzofuran- carbazole compounds WO2006114966, US20090167162 0 US20090167162 WO2009086028 US20090030202, US20090017330 US20100084966 Silicon aryl compounds US20050238919 WO2009003898 Silicon/ Germanium aryl compounds EP2034538A Aryl benzoyl ester WO2006100298 Carbazole linked by non- conjugated groups US20040115476 Aza-carbazoles US20060121308 High triplet metal organometallic complex 0 US71554114 Phosphorescent dopants Red dopants Heavy metal porphyrins (e.g., PtOEP) Nature 395, 151 (1998) Iridium(III) organometallic complexes Appl. Phys. Lett. 78, 1622 (2001) US20030072964 US20030072964 US20060202194 US20060202194 US20070087321 US20080261076 US20100090591 US20070087321 0 Adv. Mater. 19, 739 (2007) WO2009100991 WO2008101842 US7232618 Platinum(II) organometallic complexes WO2003040257 US20070103060 Osmium(III) complexes Chem. Mater. 17, 3532 (2005) Ruthenium(II) complexes Adv. Mater. 17, 1059 (2005) Rhenium (I), (II), and (III) complexes US20050244673 Green dopants Iridium(III) organometallic complexes Inorg. Chem. 40, 1704 (2001) 00 US20020034656 01 US7332232 02 US20090108737 03 WO2010028151 04 EP1841834B 05 US20060127696 06 US20090039776 07 US6921915 08 US20100244004 09 US6687266 0 Chem. Mater. 16, 2480 (2004) US20070190359 US 20060008670 JP2007123392 WO2010086089, WO2011044988 Adv. Mater. 16, 2003 (2004) Angew. Chem. Int. Ed. 2006, 45, 7800 WO2009050290 US20090165846 US20080015355 US20010015432 0 US20100295032 Monomer for polymeric metal organometallic compounds US7250226, US7396598 Pt(II) organo- metallic complexes, including poly- dentated ligands Appl. Phys. Lett. 86, 153505 (2005) Appl. Phys. Lett. 86, 153505 (2005) Chem. Lett. 34, 592 (2005) WO2002015645 US20060263635 US20060182992 US20070103060 Cu complexes WO2009000673 US20070111026 Gold complexes 0 Chem. Commun. 2906 (2005) Rhenium(III) complexes Inorg. Chem. 42, 1248 (2003) Osmium(II) complexes US7279704 Deuterated organometallic complexes US20030138657 Organometallic complexes with two or more metal centers US20030152802 US7090928 Blue dopants Iridium(III) organometallic complexes WO2002002714 WO2006009024 US20060251923 US20110057559 US20110204333 US7393599, WO2006056418, US20050260441, WO2005019373 0 US7534505 WO2011051404 US7445855 US20070190359, US20080297033 US20100148663 US7338722 US20020134984 Angew. Chem. Int. Ed 47, 4542 (2008) Chem. Mater. 18, 5119 (2006) Inorg. Chem. 46, 4308 (2007) WO2005123873 0 WO2005123873 WO2007004380 WO2006082742 Osmium(II) complexes US7279704 Organometallics 23, 3745 (2004) Gold complexes Appl. Phys. Lett. 74, 1361 (1999) Platinum(II) complexes WO2006098120, WO2006103874 Pt tetradentate complexes with at least one metal- carbene bond US7655323 Exciton/hole blocking layer materials Bathocuprine compounds (e.g., BCP, BPhen) Appl. Phys. Lett. 75, 4 (1999) Appl. Phys. Lett. 79, 449 (2001) Metal 8- hydroxyquinolates (e.g., BAlq) 0 Appl. Phys. Lett. 81, 162 (2002) 5-member ring electron deficient heterocycles such as triazole, oxadiazole, imidazole, benzoimidazole Appl. Phys. Lett. 81, 162 (2002) Triphenylene compounds US20050025993 Fluorinated aromatic compounds Appl. Phys. Lett 79, 156 (2001) Phenothiazine-S- oxide WO2008132085 Silylated five- membered nitrogen, oxygen, sulfur or phosphorus dibenzoheterocycles WO2010079051 Aza-carbazoles US20060121308 Electron transporting materials Anthracene- benzoimidazole compounds WO2003060956 US20090179554 Aza triphenylene derivatives US20090115316 Anthracene- benzothiazole compounds 0 Appl. Phys. Lett. 89, 063504 (2006) Metal 8- hydroxyquinolates (e.g., Alq.sub.3, Zrq.sub.4) Appl. Phys. Lett. 51, 913 (1987) US7230107 Metal hydroxybenzo- quinolates Chem. Lett. 5, 905 (1993) Bathocuprine compounds such as BCP, BPhen, etc Appl. Phys. Lett. 91, 263503 (2007) Appl. Phys. Lett. 79, 449 (2001) 5-member ring electron deficient heterocycles (e.g., triazole, oxadiazole, imidazole, benzoimidazole) Appl. Phys. Lett. 74, 865 (1999) Appl. Phys. Lett. 55, 1489 (1989) Jpn. J. Apply. Phys. 32, L917 (1993) Silole compounds Org. Electron. 4, 113 (2003) Arylborane compounds J. Am. Chem. Soc. 120, 9714 (1998) Fluorinated aromatic compounds 0 J. Am. Chem. Soc. 122, 1832 (2000) Fullerine (e.g., C60) US20090101870 Triazine complexes US20040036077 Zn (N{circumflex over ()}N) complexes US6528187

Experimental Data

(104) Table 1 shows the photophysical and thermal properties of the inventive Compound 1 and comparative compounds A and B. The PL spectrum was measured in dilute solution in 2-methyltetrahydrofuran at 77 K. The photoluminescence quantum yield (PLQY) listed in the table was the PLQY of the PMMA film doped with 1% of the emitter. The PLQY value of Compound A is normalized to 1. The values for Compound 1 and Compound B are relative to Compound A. The evaporation temperature was the temperature the compound started to sublime under high vacuum. (10.sup.5 torr). The melting point was measured by differential scanning calorimetry (DSC).

(105) TABLE-US-00002 TABLE 1 photophysical and thermal properties of the inventive Compound 58 and comparatives compounds A and B. PL Evaporation Melting (nm) PLQY temperature ( C.) point ( C.) Compound 58 666 1.5 225 332 Compound A 677 1.0 225 276 Compound B 658 1.7 220 254

Device Examples

(106) Table 1 shows the data comparing the inventive compound to the comparative compounds A and B. As shown by the photoluminescence (PL) values, Compound 58 emits very deep red color with a peak wavelength of 666 nm similar to the comparative compounds. All three compounds also have similar evaporation temperature, around 220 C. However, the inventive compound unexpectedly exhibited significantly higher melting point than the comparative compounds. Without being bound by the theory, the inventors believe that the increase in the melting point may be due to the steric created by the i-propyl side chains on the phenyl ring which locks the molecule into place and makes it harder to melt. The large difference between the evaporation temperature and melting point is advantageous since many of the iridium complexes start to decompose upon melting. For OLED mass production, the materials are often evaporated at a high rate to reduce takt time, which requires heating the materials at much higher temperature to speed up the evaporation. It is important that the materials do not decompose during the manufacturing process and many organometallic compounds decompose at high temperatures and provides limitations on reducing takt time. Therefore, the larger evaporation-melting temperature gap for the inventive organometallic complexes disclosed herein is desirable, ensuring the material stability during the mass production process. Therefore, the inventive compounds are more useful for OLEDs than the comparative compounds.

(107) The chemical structure of the compounds used in the device examples are shown below:

(108) Inventive Compound:

(109) ##STR00284##

(110) Comparative Compounds:

(111) ##STR00285##

(112) 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.