ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

20230006146 · 2023-01-05

Inventors

Cpc classification

International classification

Abstract

Compounds that are organic radicals that can have a dual function. The compounds can be fluorescent emitters that emit in the near-IR. The compounds can also facilitate reverse intersystem crossing (RISC) to convert triplet excitons in an OLED to singlet excited states to maximize utilization of generated excitons in the OLED and approach 100% internal quantum efficiency.

Claims

1.-19. (canceled)

20. An organic light emitting device (OLED) comprising: an anode; a cathode; and an organic layer, disposed between the anode and the cathode, the organic layer comprising a compound selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BG ##STR00300## wherein X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N; X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N; X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N; X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N; X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N; R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution; each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring; each R.sup.N is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of: ##STR00301## and any aza-analogue of each thereof, each of which is optionally substituted with R.sup.P, wherein R.sup.P is selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein R.sup.F to R.sup.I are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR′CR″, SiR′R″, and GeR′R″, wherein R′ and R″ are independently R.sup.N; with the proviso that the following compounds are excluded ##STR00302##

21. The OLED of claim 20, wherein the polycyclic group is selected from the group consisting of ##STR00303## ##STR00304## ##STR00305## ##STR00306## ##STR00307## ##STR00308## and aza-analogues thereof; wherein R.sup.F to R.sup.M and R.sup.O are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and the polycyclic group is attached through one of R.sup.1 to R.sup.M, R.sup.O or R′, wherein R′ is independently R.sup.N.

22. The OLED of claim 20, wherein the compound is selected from the group consisting of: ##STR00309## ##STR00310## ##STR00311## ##STR00312## ##STR00313## ##STR00314##

23. The OLED of claim 20, wherein the compound is selected from the group consisting of: ##STR00315## ##STR00316## ##STR00317## ##STR00318## ##STR00319## ##STR00320## ##STR00321## ##STR00322## ##STR00323## ##STR00324## ##STR00325## ##STR00326## ##STR00327## ##STR00328## ##STR00329## ##STR00330## ##STR00331##

24. The OLED of claim 20, wherein the organic layer is an emissive layer.

25. The OLED of claim 20, wherein the compound can produce emission.

26. The OLED of claim 20, wherein the compound produces emission via fluorescence or thermally activated delayed fluorescence.

27. The OLED of claim 20, wherein the compound is an emissive dopant.

28. The OLED of claim 20, wherein the organic layer further comprises a second compound, wherein the second compound is capable of emitting light by fluorescence or thermally activated delayed fluorescence.

29. The OLED of claim 28, wherein the second compound is selected from the group consisting of: ##STR00332## ##STR00333## ##STR00334## ##STR00335## ##STR00336## ##STR00337## ##STR00338## ##STR00339## ##STR00340## ##STR00341## ##STR00342## ##STR00343## ##STR00344## ##STR00345## ##STR00346## ##STR00347## ##STR00348## ##STR00349##

30. An organic light emitting device (OLED) comprising: an anode; a cathode; and an organic layer disposed between the anode and the cathode, the organic layer comprising a first compound and a second compound; wherein the first compound is selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BG ##STR00350## wherein X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N; X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N; X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N; X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N; X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N; R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution; each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring; R.sup.N is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.E, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of: ##STR00351## and any aza-analogue of each thereof, each of which is optionally substituted with R.sup.P, wherein R.sup.P is selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein R.sup.F to R.sup.I are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR′CR″, SiR′R″, and GeR′R″, wherein R′ and R″ are independently R.sup.N; with the proviso that the first compound is not ##STR00352## and wherein the second compound is a compound that is capable of emitting light by fluorescence or thermally activated delayed fluorescence.

31. The OLED of claim 30, wherein the first compound produces emission via fluorescence or thermally activated delayed fluorescence.

32. The OLED of claim 30, wherein the first compound is selected from the group consisting of: ##STR00353## ##STR00354## ##STR00355## ##STR00356## ##STR00357## ##STR00358## ##STR00359## ##STR00360##

33. The OLED of claim 30, wherein the first compound is selected from the group consisting of: ##STR00361## ##STR00362## ##STR00363## ##STR00364## ##STR00365## ##STR00366## ##STR00367## ##STR00368## ##STR00369## ##STR00370## ##STR00371## ##STR00372## ##STR00373## ##STR00374## ##STR00375## ##STR00376## ##STR00377## ##STR00378## ##STR00379## ##STR00380## ##STR00381##

34. The OLED of claim 30, wherein the second compound comprises one or more structures selected from the group consisting of: ##STR00382## and aza-analogues thereof; wherein Y.sup.1 and Y.sup.2 are each independently selected from the group consisting of O, S, Se, NR′ and CR′R″; wherein R′ and R″ are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein any two adjacent substituents R′ and R″ may optionally join to form a ring.

35. The OLED of claim 30, wherein the second compound is selected from the group consisting of: ##STR00383## ##STR00384## ##STR00385## ##STR00386## ##STR00387## ##STR00388## ##STR00389## ##STR00390## ##STR00391## ##STR00392## ##STR00393## ##STR00394## ##STR00395## ##STR00396## ##STR00397## ##STR00398## ##STR00399## ##STR00400## ##STR00401##

36. An organic light emitting device (OLED) comprising: an anode; a cathode; and an organic layer disposed between the anode and the cathode, the organic layer comprising a mixture of a first compound and a second compound; wherein the first compound is selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BG ##STR00402## wherein X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N; X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N; X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N; X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N; X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N; R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution; each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring; R.sup.N is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of: ##STR00403## and any aza-analogue of each thereof, each of which is optionally substituted with R.sup.P, wherein R.sup.P is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein R.sup.F to R.sup.I are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR′CR″, SiR′R″, and GeR′R″, wherein R′ and R″ are independently R.sup.N; with the proviso that the first compound is not ##STR00404## and wherein the second compound comprises one or more structures selected from the group consisting of: ##STR00405## ##STR00406## ##STR00407## ##STR00408## ##STR00409## wherein R.sup.1 to R.sup.9 each independently represent from mono to maximum number of substitutions they can have, or no substitution; wherein R.sup.1 to R.sup.9 are each 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; and wherein each Y.sup.1 is the same or different and is selected from the group consisting of O, S, Se, NR.sup.N and CR′R″; wherein R.sup.N, R′, and R″ are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

37. The OLED of claim 36, wherein the molar ratio of the first compound to the second compound is from 5:95 to 40:60.

38. The OLED of claim 36, wherein the first compound is selected from the group consisting of: ##STR00410## ##STR00411## ##STR00412## ##STR00413## ##STR00414## ##STR00415## ##STR00416## ##STR00417## ##STR00418## ##STR00419## ##STR00420## ##STR00421## ##STR00422## ##STR00423## ##STR00424## ##STR00425## ##STR00426## ##STR00427##

39. The OLED of claim 36, wherein the second compound is selected from the group consisting of: ##STR00428## ##STR00429## ##STR00430## ##STR00431## ##STR00432## ##STR00433## ##STR00434## ##STR00435## ##STR00436## ##STR00437## ##STR00438## ##STR00439## ##STR00440## ##STR00441## ##STR00442## ##STR00443## ##STR00444## ##STR00445## ##STR00446## ##STR00447## ##STR00448##

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 shows an organic light emitting device.

[0032] FIG. 2 shows an inverted organic light emitting device that does not have a separate electron transport layer.

DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] More recently, OLEDs having emissive materials that emit light from triplet states (“phosphorescence”) have been demonstrated. Baldo et al., “Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices,” Nature, vol. 395, 151-154, 1998; (“Baldo-I”) and Baldo et al., “Very high-efficiency green organic light-emitting devices based on electrophosphorescence,” Appl. Phys. Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), are incorporated by reference in their entireties. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporated by reference.

[0036] 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.

[0037] The invention is directed to select organic radicals. The organic radicals can have a dual function. First, many of the inventive organic radicals are known to be fluorescent emitters with an emission in a range from 700 nm to 1100 nm. Second, and perhaps more importantly, the doublet state of the organic radical can facilitate reverse intersystem crossing (RISC) to convert triplet excitons in an OLED to singlet excited states to maximize utilization of excitons generated in the OLED to approach 100% internal quantum efficiency. Radical-assisted RISC can be achieved by both chemical and physical blending of a fluorescent emitter and the organic radical into an emissive layer of an OLED device. In addition to radical-assisted RISC, if a pendent organic radical is conjugated to the fluorescent emitter, the emitter becomes a doublet emitter that also utilize all injected carriers to approach 100% internal quantum efficiency. Many of these organic radicals are what those skilled in the art would deem to be air-stable.

[0038] The organic radical can facilitate reverse intersystem crossing (RISC) when the radical and the emitter have no electronic communication (for example, compound 77, 2015, 2984, etc.), or make the fluorescent emitter become a doublet emitter when the radical can interact with the fluorescent chromophore through resonance (for example, compound 69, 715, 1038, etc.). In both cases, the radical in combination with a fluorescent emitter makes it possible to achieve 100% internal quantum efficiency (IQE) in an OLED. So far there are only two types of emitters that are widely used and can approach 100% IQE: i) phosphorescent emitters and ii) TADF (thermal-assisted delay fluorescence) emitters. Radical-assisted RISC emitters and doublet emitters will be the next generation highly efficient OLED emitters.

[0039] 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 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties, organic vapor phase deposition (OVPD), such as described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety, and deposition by organic vapor jet printing (OVJP), such as described in U.S. Pat. No. 7,431,968, which is incorporated by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, and patterning associated with some of the deposition methods such as ink-jet and organic vapor jet printing (OVJP). Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having 20 carbons or more may be used, and 3-20 carbons 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.

[0044] 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.

[0045] Devices fabricated in accordance with embodiments of the invention can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into a variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include display screens, lighting devices such as discrete light source devices or lighting panels, etc. that can be utilized by the end-user product manufacturers. Such electronic component modules can optionally include the driving electronics and/or power source(s). Devices fabricated in accordance with embodiments of the invention can be incorporated into a wide variety of consumer products that have one or more of the electronic component modules (or units) incorporated therein. A consumer product comprising an OLED that includes the compound of the present disclosure in the organic layer in the OLED is disclosed. Such consumer products would include any kind of products that include one or more light source(s) and/or one or more of some type of visual displays. Some examples of such consumer products include flat panel displays, curved displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully or partially transparent displays, flexible displays, rollable displays, foldable displays, stretchable displays, laser printers, telephones, mobile phones, tablets, phablets, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, camcorders, viewfinders, micro-displays (displays that are less than 2 inches diagonal), 3-D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screen, and a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as 18 degrees C. to 30 degrees C., and more preferably at room temperature (20-25 degrees C.), but could be used outside this temperature range, for example, from −40 degree C. to +80 degree C.

[0046] 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.

[0047] The terms “halo,” “halogen,” and “halide” are used interchangeably and refer to fluorine, chlorine, bromine, and iodine.

[0048] The term “acyl” refers to a substituted carbonyl radical (C(O)—R.sub.s).

[0049] The term “ester” refers to a substituted oxycarbonyl (—O—C(O)—R.sub.s or —C(O)—O—R.sub.s) radical.

[0050] The term “ether” refers to an —OR.sub.s radical.

[0051] The terms “sulfanyl” or “thio-ether” are used interchangeably and refer to a —SR.sub.s radical.

[0052] The term “sulfinyl” refers to a —S(O)—R.sub.s radical.

[0053] The term “sulfonyl” refers to a —SO.sub.2—R.sub.s radical.

[0054] The term “phosphino” refers to a —P(R.sub.s).sub.3 radical, wherein each R.sub.s can be same or different.

[0055] The term “silyl” refers to a —Si(R.sub.s).sub.3 radical, wherein each R.sub.s can be same or different.

[0056] In each of the above, R.sub.s can be hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, and combination thereof. Preferred R.sub.s is selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl, and combination thereof.

[0057] The term “alkyl” refers to and includes both straight and branched chain alkyl radicals. Preferred alkyl groups are those containing from one to fifteen carbon atoms and includes methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, and the like. Additionally, the alkyl group is optionally substituted.

[0058] The term “cycloalkyl” refers to and includes monocyclic, polycyclic, and spiro alkyl radicals. Preferred cycloalkyl groups are those containing 3 to 12 ring carbon atoms and includes cyclopropyl, cyclopentyl, cyclohexyl, bicyclo[3.1.1]heptyl, spiro[4.5]decyl, spiro[5.5]undecyl, adamantyl, and the like. Additionally, the cycloalkyl group is optionally substituted.

[0059] The terms “heteroalkyl” or “heterocycloalkyl” refer to an alkyl or a cycloalkyl radical, respectively, having at least one carbon atom replaced by a heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si and Se, preferably, O, S or N. Additionally, the heteroalkyl or heterocycloalkyl group is optionally substituted.

[0060] The term “alkenyl” refers to and includes both straight and branched chain alkene radicals. Alkenyl groups are essentially alkyl groups that include at least one carbon-carbon double bond in the alkyl chain. Cycloalkenyl groups are essentially cycloalkyl groups that include at least one carbon-carbon double bond in the cycloalkyl ring. The term “heteroalkenyl” as used herein refers to an alkenyl radical having at least one carbon atom replaced by a heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, and Se, preferably, O, S, or N. Preferred alkenyl, cycloalkenyl, or heteroalkenyl groups are those containing two to fifteen carbon atoms. Additionally, the alkenyl, cycloalkenyl, or heteroalkenyl group is optionally substituted.

[0061] The term “alkynyl” refers to and includes both straight and branched chain alkyne radicals. Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group is optionally substituted.

[0062] The terms “aralkyl” or “arylalkyl” are used interchangeably and refer to an alkyl group that is substituted with an aryl group. Additionally, the aralkyl group is optionally substituted.

[0063] The term “heterocyclic group” refers to and includes aromatic and non-aromatic cyclic radicals containing at least one heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, and Se, preferably, O, S, or N. Hetero-aromatic cyclic radicals may be used interchangeably with heteroaryl. Preferred hetero-non-aromatic cyclic groups are those containing 3 to 7 ring atoms which includes at least one hetero atom, and includes cyclic amines such as morpholino, piperidino, pyrrolidino, and the like, and cyclic ethers/thio-ethers, such as tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, and the like. Additionally, the heterocyclic group may be optionally substituted.

[0064] The term “aryl” refers to and includes both single-ring aromatic hydrocarbyl groups and polycyclic aromatic 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 an aromatic hydrocarbyl group, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls. Preferred aryl groups are those containing six to thirty carbon atoms, preferably six to twenty carbon atoms, more preferably six to twelve carbon atoms. Especially preferred is an aryl group having six carbons, ten carbons or twelve carbons. Suitable aryl groups include phenyl, biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene, preferably phenyl, biphenyl, triphenyl, triphenylene, fluorene, and naphthalene. Additionally, the aryl group is optionally substituted.

[0065] The term “heteroaryl” refers to and includes both single-ring aromatic groups and polycyclic aromatic ring systems that include at least one heteroatom. The heteroatoms include, but are not limited to O, S, N, P, B, Si, and Se. In many instances, O, S, or N are the preferred heteroatoms. Hetero-single ring aromatic systems are preferably single rings with 5 or 6 ring atoms, and the ring can have from one to six heteroatoms. The hetero-polycyclic ring systems can have two or more 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. The hetero-polycyclic aromatic ring systems can have from one to six heteroatoms per ring of the polycyclic aromatic ring system. Preferred heteroaryl groups are those containing three to thirty carbon atoms, preferably three to twenty carbon atoms, more preferably three to twelve carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine, preferably dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, triazine, benzimidazole, 1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazine, and aza-analogs thereof. Additionally, the heteroaryl group is optionally substituted.

[0066] Of the aryl and heteroaryl groups listed above, the groups of triphenylene, naphthalene, anthracene, dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, pyrazine, pyrimidine, triazine, and benzimidazole, and the respective aza-analogs of each thereof are of particular interest.

[0067] The terms alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aralkyl, heterocyclic group, aryl, and heteroaryl, as used herein, are independently unsubstituted, or independently substituted, with one or more general substituents.

[0068] In many instances, the general substituents are selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

[0069] In some instances, the preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.

[0070] In some instances, the preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silyl, aryl, heteroaryl, sulfanyl, and combinations thereof.

[0071] In yet other instances, the more preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof.

[0072] The term “substituted” refers to a substituent other than H that is bonded to the relevant position, e.g., a carbon. For example, where R.sup.1 represents mono-substituted, then one R.sup.1 must be other than H. Similarly, where R.sup.1 represents 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. The maximum number of substitutions possible in a structure (for example, a particular ring or fused ring system) will depend on the number of atoms with available valencies.

[0073] As used herein, “combinations thereof” indicates that one or more members of the applicable list are combined to form a known or chemically stable arrangement that one of ordinary skill in the art can envision from the applicable list. For example, an alkyl and deuterium can be combined to form a partial or fully deuterated alkyl group; a halogen and alkyl can be combined to form a halogenated alkyl substituent; and a halogen, alkyl, and aryl can be combined to form a halogenated arylalkyl. In one instance, the term substitution includes a combination of two to four of the listed groups. In another instance, the term substitution includes a combination of two to three groups. In yet another instance, the term substitution includes a combination of two groups. Preferred combinations of substituent groups are those that contain up to fifty atoms that are not hydrogen or deuterium, or those which include up to forty atoms that are not hydrogen or deuterium, or those that include up to thirty atoms that are not hydrogen or deuterium. In many instances, a preferred combination of substituent groups will include up to twenty atoms that are not hydrogen or deuterium.

[0074] 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.

[0075] As used herein, “deuterium” refers to an isotope of hydrogen. Deuterated compounds can be readily prepared using methods known in the art. For example, U.S. Pat. No. 8,557,400, Patent Pub. No. WO 2006/095951, and U.S. Pat. Application Pub. No. US 2011/0037057, which are hereby incorporated by reference in their entireties, describe the making of deuterium-substituted organometallic complexes. Further reference is made to Ming Yan, et al., Tetrahedron 2015, 71, 1425-30 and Atzrodt et al., Angew. Chem. Int. Ed. (Reviews) 2007, 46, 7744-65, which are incorporated by reference in their entireties, describe the deuteration of the methylene hydrogens in benzyl amines and efficient pathways to replace aromatic ring hydrogens with deuterium, respectively.

[0076] 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.

Compounds of the Invention

[0077] A compound selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF. A person of ordinary skill recognizes that the dot represents the radical in the compound, and further understands that its respective stated position in the compound is not fixed at the one atom shown. Instead, the free-radical is more likely distributed among the overlapping molecular orbitals of the compound, which is known to provide the additional stability observed in the compounds.

##STR00006##

[0078] For the respective compounds of Formulae BB, BC, BD, BE, BF, and BF:

[0079] X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N;

[0080] X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N;

[0081] X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N;

[0082] X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N;

[0083] X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N;

[0084] R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution;

[0085] each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring;

[0086] R.sup.N is independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, heteroalkyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, and combinations thereof;

[0087] wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of:

##STR00007## ##STR00008##

and any aza-analogue of each thereof, each of which is optionally substituted with R.sup.P, wherein R.sup.P is selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof;

[0088] wherein R.sup.F to R.sup.I are independently selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof; and

[0089] Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR′CR″, SiR′R″, and GeR′R″, wherein R′ and R″ are independently R.sup.N;

[0090] with the proviso that the following compound is excluded

##STR00009##

[0091] In one embodiment, each R.sup.1 to R.sup.5, and each R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, fluorine, chlorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silyl, aryl, heteroaryl, nitrile, and combinations thereof. In another embodiment, each R.sup.1 to R.sup.5, and each R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, fluorine, chlorine, nitrile, alkyl, aryl, heteroaryl, and combinations thereof.

[0092] In one embodiment, at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E comprise a structure capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device with an internal quantum efficiency of greater than 3% at room temperature. In one embodiment, at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E comprises a structure capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device with an internal quantum efficiency of greater than 6% at room temperature. In one embodiment, at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E comprises a structure capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device with an internal quantum efficiency of greater than 9% at room temperature.

[0093] Polycyclic groups of interest are selected from the group consisting of

##STR00010## ##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016##

and aza-analogues thereof;

[0094] wherein R.sup.F to R.sup.M and R.sup.O are independently selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof, and the polycyclic group is attached through one of R.sup.F to R.sup.M, R.sup.O or R′, wherein R′ is R.sup.N.

[0095] In one embodiment, the compound of Formula BB is selected from the group consisting of:

##STR00017## ##STR00018## ##STR00019##

[0096] In one embodiment, the compound of Formula BE is selected from the group consisting of:

##STR00020## ##STR00021## ##STR00022##

[0097] In one embodiment, the compound of Formula BD is selected from the group consisting of:

##STR00023## ##STR00024##

[0098] Select compounds of interest are selected from the group consisting of:

##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030## ##STR00031## ##STR00032## ##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042##

[0099] In one embodiment, the compounds of Formulae BB, BC, BD, BE, BF, and BF, will have a peak emission wavelength λ.sub.max in a range from 700 nm to 1100 nm. In one embodiment, the compound has a peak emission wavelength λ.sub.max in a range from 800 nm to 100 nm. In one embodiment, the compound has a peak emission wavelength λ.sub.max in a range from 825 nm to 950 nm.

[0100] The invention is also directed to a compound of formula A-L-B; wherein Component A is a fluorescent emitter, which includes fluorescent compounds that are known and referred to in the art as thermally-assisted delayed fluorescence emitters. Alternatively, Component A is a structure listed in Table 1 below. Component B comprises a structure selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF, above; and L is a direct bond or an organic linker. Alternatively, Component B is B1 to B10 listed in Table 1 below.

[0101] The invention is also directed to a formulation, or a mixture, of a Component A and a Component B. Component A is a fluorescent emitter that includes fluorescent compounds known and referred to in the art as thermally-assisted delayed fluorescence emitters. Alternatively, Component A is a structure listed in Table 1 below. Component B comprises a structure selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF, above; and L is a direct bond or an organic linker. Alternatively, Component B is B1 to B10 listed in Table 1 below.

[0102] In the two distinct embodiments above, that is, in a compound of formula A-L-B, or a mixture of Components A and B, Component A can include a structure or compound, respectively, selected from the group consisting of:

##STR00043## ##STR00044## ##STR00045## ##STR00046## ##STR00047## ##STR00048## ##STR00049## ##STR00050## ##STR00051## ##STR00052## ##STR00053## ##STR00054## ##STR00055## ##STR00056## ##STR00057## ##STR00058## ##STR00059## ##STR00060## ##STR00061## ##STR00062##

Component B may be a structure or compound, respectively, selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF:

##STR00063##

For the respective compounds of the Formulae BB, BC, BD, BE, BF, and BF:

[0103] X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N;

[0104] X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N;

[0105] X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N;

[0106] X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N;

[0107] X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N;

[0108] R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution;

[0109] each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring;

[0110] R.sup.N is independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, heteroalkyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, and combinations thereof;

[0111] wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of:

##STR00064##

and any aza-analogue of each thereof, each of which is optionally substituted with R.sup.P, wherein R.sup.P is selected from the group consisting of deuterium, fluorine, chlorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof;

[0112] wherein R.sup.F to R.sup.I are independently selected from the group consisting of deuterium, fluorine, chlorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof; and

[0113] Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR′CR″, SiR′R″, and GeR′R″, wherein R′ and R″ are independently R.sup.N;

[0114] with the proviso that the following compound is excluded

##STR00065##

Alternatively, Component B is B1 to B10 listed in Table 1 below.

[0115] For the compounds, A-L-B, organic linkers of interest are selected from a direct bond, a divalent aryl, or a divalent heteroaryl. In one embodiment, L can include 2-36 carbon atoms or an aromatic group. In one embodiment, L comprises a carbocyclic group. Select organic linkers of interest can be selected from one of L1 to L17 below.

[0116] In one embodiment, the compound is a Compound X having the formula Ai-Lf-Bk.

[0117] Lj is selected from the group consisting of:

##STR00066## ##STR00067##

[0118] Bk is selected from the group consisting of:

##STR00068## ##STR00069##

[0119] * attaches to Lj [0120] * represents the point of attachment of Bk to the linker Li; and Ai is indicated below to provide the following compounds listed in Table 1.

TABLE-US-00001 TABLE 1 Ai Ci Lj Bk x equals to Compound x [00070] embedded image i is an integer from 1 to 19 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 323(k − 1) Compound 1-3230 [00071] i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 3230 Compound 3231-6120 [00072] embedded image i is an integer from 1 to 22 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 374(k − 1) + 6120 Compound 6121-9860 [00073] i is an integer from 1 to 20 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 340(k − 1) + 9860 Compound 9861-13260 [00074] embedded image i is an integer from 1 to 20 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 340(k − 1) + 13260 Compound 13261-16830 [00075] i is an integer from 1 to 21 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 357(k − 1) + 16830 Compound 16831-20400 [00076] embedded image i is an integer from 1 to 21 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 357(k − 1) + 20400 Compound 20401-23970 [00077] i is an integer from 1 to 7 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 119(k − 1) + 23970 Compound 23971-25160 [00078] embedded image i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 25160 Compound 25161-27540 [00079] i is an integer from 1 to 11 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 187(k − 1) + 27540 Compound 27541-29410 [00080] embedded image i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 29410 Compound 29411-29580 [00081] i is an integer from 1 to 16 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 272(k − 1) + 29580 Compound 29581-32300 [00082] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 32300 Compound 32301-34510 [00083] embedded image i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 34510 Compound 34511-34680 [00084] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 34680 Compound 34681-36890 [00085] i is an integer from 1 to 10 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 170(k − 1) + 36890 Compound 36891-38590 [00086] embedded image i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 38590 Compound 38591-38760 [00087] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 38760 Compound 38761-40970 [00088] i is an integer from 1 to 15 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 255(k − 1) + 40970 Compound 40971-43520 [00089] embedded image i is an integer from 1 to 12 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 204(k − 1) + 43520 Compound 43521-45560 [00090] i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 45560 Compound 45561-47940 [00091] embedded image i is an integer from 1 to 11 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 187(k − 1) + 47940 Compound 47941-49810 [00092] i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 49810 Compound 49811-49980 [00093] i is an integer from 1 to 16 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 272(k − 1) + 49980 Compound 49981-52700 [00094] embedded image i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 52700 Compound 52701-54910 [00095] i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 54910 Compound 54911-55080 [00096] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 55080 Compound 55081-57290 [00097] embedded image i is an integer from 1 to 10 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 170(k − 1) + 52700 Compound 57291-58990 [00098] i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 58990 Compound 58991-59160 [00099] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 59160 Compound 59161-61370 [00100] embedded image i is an integer from 1 to 15 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 255(k − 1) + 61370 Compound 61371-63920 [00101] i is an integer from 1 to 12 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 204(k − 1) + 63920 Compound 63921-65960 [00102] embedded image i is an integer from 1 to 9 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 153(k − 1) + 65960 Compound 65961-67490 [00103] i is an integer from 1 to 9 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 153(k − 1) + 67490 Compound 67491-69020 [00104] embedded image i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 69020 Compound 69021-71400 [00105] i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 71400 Compound 71401-73780 [00106] embedded image i is an integer from 1 to 25 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 425(k − 1) + 73780 Compound 73781-78030 [00107] i is an integer from 1 to 21 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 357(k − 1) + 78030 Compound 78031-81600 [00108] embedded image i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 81600 Compound 81601-84490 [00109] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 84490 Compound 84491-86700 [00110] embedded image i is an integer from 1 to 21 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 357(k − 1) + 86700 Compound 86701-90270 [00111] i is an integer from 1 to 25 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 425(k − 1) + 90270 Compound 90271-94520 [00112] embedded image i is an integer from 1 to 16 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 272(k − 1) + 94520 Compound 94521-97240 [00113] i is an integer from 1 to 20 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 340(k − 1) + 97240 Compound 97241- 100640 [00114] embedded image i is an integer from 1 to 8 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 136(k − 1) + 100640 Compound 100641- 102000 [00115] i is an integer from 1 to 15 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 255(k − 1) + 102000 Compound 102001- 104550 [00116] embedded image i is an integer from 1 to 15 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 255(k − 1) + 104550 Compound 104551- 107100 [00117] i is an integer from 1 to 10 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 170(k − 1) + 107100 Compound 107101- 108800 [00118] embedded image i is an integer from 1 to 15 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 255(k − 1) + 108800 Compound 108801- 111350 [00119] i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 111350 Compound 111351- 113730 [00120] embedded image i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 113730 Compound 113731- 116110 [00121] i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 116110 Compound 116111- 119000 [00122] embedded image i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 119000 Compound 119001- 121380 [00123] i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 121380 Compound 121381- 124270 [00124] embedded image i is an integer from 1 to 31 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 527(k − 1) + 124270 Compound 124271- 129540 [00125] i is an integer from 1 to 29 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 493(k − 1) + 129540 Compound 129541- 134470 [00126] embedded image i is an integer from 1 to 29 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 493(k − 1) + 134470 Compound 134471- 139400 [00127] i is an integer from 1 to 35 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 595(k − 1) + 139400 Compound 139401- 145350 [00128] embedded image i is an integer from 1 to 29 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 493(k − 1) + 145350 Compound 145351- 150280 [00129] i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 150280 Compound 150281- 152660 [00130] embedded image i is an integer from 1 to 24 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 408(k − 1) + 152660 Compound 152661- 156740 [00131] i is an integer from 1 to 22 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 374(k − 1) + 156740 Compound 156741- 160480 [00132] embedded image i is an integer from 1 to 22 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 374(k − 1) + 160480 Compound 160481- 164220 [00133] i is an integer from 1 to 28 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 476(k − 1) + 164220 Compound 164221- 168980 [00134] embedded image i is an integer from 1 to 22 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 374(k − 1) + 168980 Compound 168981- 172720 [00135] i is an integer from 1 to 7 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 119(k − 1) + 172720 Compound 172721- 173910 [00136] embedded image i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 173910 Compound 173911- 176290 [00137] i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 176290 Compound 176291- 178500 [00138] embedded image i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 178500 Compound 178501- 180710 [00139] i is an integer from 1 to 16 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 272(k − 1) + 180710 Compound 180711- 183430 [00140] embedded image i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 183430 Compound 183431- 185640 [00141] i is an integer from 1 to 6 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 102(k − 1) + 185640 Compound 185641- 186660 [00142] embedded image i is an integer from 1 to 13 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 221(k − 1) + 186660 Compound 186661- 188870 [00143] i is an integer from 1 to 10 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 170(k − 1) + 188870 Compound 188871- 190570 [00144] embedded image i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 190570 Compound 190571- 193460 [00145] i is an integer from 1 to 16 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 272(k − 1) + 193460 Compound 193461- 196180 [00146] embedded image i is an integer from 1 to 9 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 153(k − 1) + 196180 Compound 196181- 197710 [00147] i is an integer from 1 to 5 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 85(k − 1) + 197710 Compound 197711- 198560 [00148] embedded image i is an integer from 1 to 12 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 204(k − 1) + 198560 Compound 198561- 200600 [00149] i is an integer from 1 to 11 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 187(k − 1) + 200600 Compound 200601- 202470 [00150] embedded image i is an integer from 1 to 11 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 187(k − 1) + 202470 Compound 202471- 204340 [00151] i is an integer from 1 to 14 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 238(k − 1) + 204340 Compound 204341- 206720 [00152] embedded image i is an integer from 1 to 11 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 187(k − 1) + 206720 Compound 206721- 208590 [00153] i is an integer from 1 to 5 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 85(k − 1) + 208590 Compound 208591- 209440 [00154] embedded image i is an integer from 1 to 3 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 51(k − 1) + 209440 Compound 209441- 209950 [00155] i is an integer from 1 to 9 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 153(k − 1) + 209950 Compound 209951- 211480 [00156] embedded image i is an integer from 1 to 5 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 85(k − 1) + 211480 Compound 211481- 212330 [00157] i is an integer from 1 to 10 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 170(k − 1) + 212330 Compound 212331- 214030 [00158] embedded image i is an integer from 1 to 11 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 187(k − 1) + 214030 Compound 214031- 215900 [00159] i is an integer from 1 to 9 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 153(k − 1) + 215900 Compound 215901- 217430 [00160] embedded image i is an integer from 1 to 9 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 153(k − 1) + 217430 Compound 217431- 218960 [00161] i is an integer from 1 to 8 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 119(k − 1) + 218960 Compound 218961- 220150 [00162] embedded image i is an integer from 1 to 6 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 102(k − 1) + 220150 Compound 220151- 221170 [00163] i is an integer from 1 to 12 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 204(k − 1) + 221170 Compound 221171- 223210 [00164] embedded image i is an integer from 1 to 4 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 68(k − 1) + 223210 Compound 223211- 223890 [00165] i is an integer from 1 to 5 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 85(k − 1) + 223890 Compound 223891- 224740 [00166] embedded image i is an integer from 1 to 23 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 391(k − 1) + 224740 Compound 224741- 228650 [00167] i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 228650 Compound 228651- 228820 [00168] i is an integer from 1 to 19 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 323(k − 1) + 228820 Compound 228821- 232050 [00169] embedded image i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 232050 Compound 232051- 232220 [00170] i is an integer from 1 to 21 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 357(k − 1) + 232220 Compound 232221- 235790 [00171] i = 1 j is an integer from 1 to 17 k is an integer from 1 to 10 j + 17(k − 1) + 235790 Compound 235791- 235960 [00172] embedded image i is an integer from 1 to 19 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 323(k − 1) + 235960 Compound 235961- 239190 [00173] i is an integer from 1 to 21 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 357(k − 1) + 239190 Compound 239191- 242760 [00174] embedded image i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 242760 Compound 242761- 245650 [00175] i is an integer from 1 to 17 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 289(k − 1) + 245650 Compound 245651- 248540 [00176] embedded image i is an integer from 1 to 19 j is an integer from 1 to 17 k is an integer from 1 to 10 17(i − 1) + j + 323(k − 1) + 248540 Compound 248541- 251770

[0121] In one embodiment, A is capable of emitting light by fluorescence or what is referred to in the art as thermally activated delayed fluorescence (TADF). Of particular interest are fluorescent or TADF emitters with emission in the blue to green region of the visible spectrum.

[0122] Of particular interest are compounds A-L-B that have a peak emission wavelength λ.sub.max in a range from 400 nm to 550 nm. The different embodiments of compounds A-L-B are described above. In another embodiment, the compounds A-L-B have a peak emission wavelength λ.sub.max in a range from 425 nm to 500 nm, a have a peak emission wavelength λ.sub.max in a range from 440 nm to 480 nm.

[0123] Of particular interest are mixtures of a Component A and a Component B, each of which is described above, that have a peak emission wavelength λ.sub.max in a range from 425 nm to 500 nm, a have a peak emission wavelength λ.sub.max in a range from 440 nm to 480 nm.

[0124] The invention is also directed to an organic light emitting device (OLED) comprising an anode; a cathode; and an organic layer disposed between the anode and the cathode. The organic layer includes a compound selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF:

##STR00177##

For the respective compounds of the Formulae BB, BC, BD, BE, BF, and BF:

[0125] wherein

[0126] X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N;

[0127] X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N;

[0128] X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N;

[0129] X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N;

[0130] X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N;

[0131] R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution;

[0132] each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring;

[0133] R.sup.N is independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, heteroalkyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, and combinations thereof;

[0134] wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of:

##STR00178##

[0135] wherein R.sup.F to R.sup.I are independently selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof; and

[0136] Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR′CR″, SiR′R″, and GeR′R″, wherein R′ and R″ are independently R.sup.N;

[0137] with the proviso that the following compound is excluded

##STR00179##

[0138] The present invention also includes an organic light emitting device (OLED) comprising an anode; a cathode; and an organic layer disposed between the anode and the cathode. In one embodiment, the organic layer includes one of the compound of formula A-L-B or select compounds of formula Ai-Li-Bk of Table 1. Component A described above is capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device. Component B is an organic radical selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF as defined above. L is selected from the group consisting of a direct bond and an organic linker. Alternatively, L can be one of the select organic linkers L2 to L17

[0139] In one embodiment, Component A is capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device with an internal quantum efficiency of greater than 3% at room temperature. In one embodiment, Component A is capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device with an internal quantum efficiency of greater than 6% at room temperature. In one embodiment, Component A is capable of emitting light from a singlet excited state to a singlet ground state in an organic light emitting device with an internal quantum efficiency of greater than 9% at room temperature.

[0140] In one embodiment, L is a direct bond. In one embodiment, L is a divalent aryl or heteroaryl. In one embodiment, L comprises 2-36 carbon atoms. In one embodiment, L comprises an aromatic group. In one embodiment, L comprises a carbocyclic group.

[0141] In some embodiments, the OLED has one or more characteristics selected from the group consisting of being flexible, being rollable, being foldable, being stretchable, and being curved. In some embodiments, the OLED is transparent or semi-transparent. In some embodiments, the OLED further comprises a layer comprising carbon nanotubes.

[0142] In some embodiments, the OLED further comprises a layer comprising a delayed fluorescent emitter. In some embodiments, the OLED comprises a RGB pixel arrangement or white plus color filter pixel arrangement. In some embodiments, the OLED is a mobile device, a hand held device, or a wearable device. In some embodiments, the OLED is a display panel having less than 10 inch diagonal or 50 square inch area. In some embodiments, the OLED is a display panel having at least 10 inch diagonal or 50 square inch area. In some embodiments, the OLED is a lighting panel.

[0143] It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistics limit through delayed fluorescence. As used herein, there are two types of delayed fluorescence, i.e. P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence is generated from triplet-triplet annihilation (TTA).

[0144] E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the thermal population between the triplet states and the singlet excited states. Compounds that are capable of generating E-type delayed fluorescence are required to have very small singlet-triplet gaps. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A distinctive feature of TADF is that the delayed component increases as temperature rises due to the increased thermal energy. If the reverse intersystem crossing rate is fast enough to minimize the non-radiative decay from the triplet state, the fraction of back populated singlet excited states can potentially reach 75%. The total singlet fraction can be 100%, far exceeding the spin statistics limit for electrically generated excitons.

[0145] E-type delayed fluorescence characteristics can be found in an exciplex system or in a single compound. Without being bound by theory, it is believed that E-type delayed fluorescence requires the luminescent material to have a small singlet-triplet energy gap (ΔEs-τ). Organic, non-metal containing, donor-acceptor luminescent materials may be able to achieve this. The emission in these materials is often characterized as a donor-acceptor charge-transfer (CT) type emission. The spatial separation of the HOMO and LUMO in these donor-acceptor type compounds often results in small AES-T. These states may involve CT states. Often, donor-acceptor luminescent materials are constructed by connecting an electron donor moiety such as amino- or carbazole-derivatives and an electron acceptor moiety such as N-containing six-membered aromatic ring.

[0146] In one embodiment, the organic layer further comprises a host, 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.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), CH═CH—C.sub.nH.sub.2n+1, C≡CC.sub.nH.sub.2n+1, Ar.sub.1, Ar.sub.1-Ar.sub.2, C.sub.nH.sub.2n-Ar.sub.1, or no substitution;

[0147] wherein n is from 1 to 10; and

[0148] 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.

[0149] In one embodiment, the organic layer further comprises a host, wherein the host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

[0150] In one embodiment, the host is selected from the group consisting of:

##STR00180## ##STR00181## ##STR00182##

and combinations thereof.

[0151] In some embodiments, the compound can be an emissive dopant. In some embodiments, the compound can produce emissions via phosphorescence, fluorescence, thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence; see, e.g., U.S. application Ser. No. 15/700,352, which is hereby incorporated by reference in its entirety), triplet-triplet annihilation, or combinations of these processes.

[0152] According to another aspect, a formulation comprising the compound described herein is also disclosed.

[0153] The OLED disclosed herein can be incorporated into one or more of a consumer product, an electronic component module, and a lighting panel. The organic layer can be an emissive layer and the compound can be an emissive dopant in some embodiments, while the compound can be a non-emissive dopant in other embodiments.

[0154] The invention is also directed to a consumer product comprising an organic light emitting device (OLED) described above. The OLED comprises an anode; a cathode; and an organic layer, disposed between the anode and the cathode. In one embodiment, the organic layer includes a compound selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF:

##STR00183##

[0155] wherein

[0156] X.sub.1 to X.sub.5 are independently selected from CR.sup.A or N;

[0157] X.sub.6 to X.sub.10 are independently selected from CR.sup.B or N;

[0158] X.sub.11 to X.sub.15 are independently selected from CR.sup.C or N;

[0159] X.sub.16 to X.sub.23 are independently selected from CR.sup.D or N;

[0160] X.sub.24 to X.sub.31 are independently selected from CR.sup.E or N;

[0161] R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E independently represent mono to the maximum allowable substitution, or no substitution;

[0162] each R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent R.sup.1 to R.sup.4, or any two adjacent R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E, can join to form a ring;

[0163] R.sup.N is independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, heteroalkyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, and combinations thereof;

wherein at least one of R.sup.1 to R.sup.5, R.sup.A, R.sup.B, R.sup.C, R.sup.D, or R.sup.E includes a polycyclic group selected from the group consisting of:

##STR00184##

and any aza analogue of each thereof, each of which is optionally substituted with R.sup.P, wherein R.sup.P is selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof;

[0164] wherein R.sup.F to R.sup.I are independently selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, amino, aryl, heteroaryl, silyl, nitrile, and combinations thereof;

[0165] and

[0166] Z and Z.sup.1 are independently selected from the group consisting of O, S, Se, NR.sup.N, CR.sup.1CR.sup.2, SiR.sup.1R.sup.2, and GeR.sup.1R.sup.2;

[0167] with the proviso that the following compound is excluded

##STR00185##

[0168] The present invention also includes a consumer product comprising an organic light emitting device (OLED) comprising an anode; a cathode; and an organic layer disposed between the anode and the cathode. In one embodiment, the organic layer includes a compound of formula A-L-B or A.sub.i-L.sub.i-B.sub.k described above. Alternatively, the OLED comprises an organic layer with a mixture of a Component A and a Component B as described above.

[0169] The present invention also includes a consumer product comprising an organic light emitting device (OLED) comprising an anode; a cathode; and an organic layer disposed between the anode and the cathode. In one embodiment, the organic layer includes a formulation comprising a Component A that functions as a fluorescent emitter in an organic light emitting device at room temperature; and a Component B. Component A is a fluorescent emitter that includes fluorescent compounds known and referred to in the art as thermally-assisted delayed fluorescence emitters. Alternatively, Component A is a structure listed in Table 1 below. Component B comprises a structure selected from the group consisting of Formulae BB, BC, BD, BE, BF, and BF, above; and L is a direct bond or an organic linker. Alternatively, Component B is B1 to B10 listed in Table 1 above. For the more preferred formulations, the molar ratio of Component A to Component B in the formulation is from 95:5 to 60:40, e.g., from 95:15 to 80:20, from 90:10 to 70:30.

[0170] In one embodiment, the consumer product is selected from the group consisting of a flat panel display, a curved display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a mobile phone, a tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display less than 2 inches diagonal), a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, and a sign.

[0171] In one embodiment, the consumer product is a virtual reality or augmented reality display.

[0172] The organic layer can also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the hosts used maybe a) bipolar, b) electron transporting, c) hole transporting or d) wide band gap materials that play little role in charge transport. In some embodiments, the host can include a metal complex. The host can be a triphenylene containing benzo-fused thiophene or benzo-fused furan. Any substituent in the host can be an unfused substituent independently selected from the group consisting of C.sub.nH.sub.2n+1, OC.sub.nH.sub.2n+1, OAr.sub.1, N(Ar.sub.1)(Ar.sub.2), CH═CH—C.sub.nH.sub.2n+1, C≡C—C.sub.nH.sub.2n+1, Ar.sub.1, Ar.sub.1-Ar.sub.2, and C.sub.nH.sub.2n-Ar.sub.1, or the host has no substitutions. In the preceding substituents n can range from 1 to 10; and Ar.sub.1 and Ar.sub.2 can be independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof. The host can be an inorganic compound. For example a Zn containing inorganic material e.g. ZnS.

[0173] The host can be a compound comprising at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene. The host can include a metal complex. The host can be, but is not limited to, a specific compound selected from the group consisting of:

##STR00186## ##STR00187## ##STR00188##

and combinations thereof.
Additional information on possible hosts is provided below.

[0174] The invention is also directed to a formulation that comprises one or more of the compounds described herein. 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, electron blocking material, hole blocking material, and an electron transport material, disclosed herein.

[0175] In one embodiment. Component A comprises one or more structures selected from the group consisting of:

##STR00189##

and aza-analogues thereof;

[0176] wherein Y.sup.1 and Y.sup.2 are each independently selected from the group consisting of O, S, Se, NR′ and CR′R″; wherein R′ and R″ are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; or optionally, any two adjacent substituents of R′ and R″ can join to form a ring.

[0177] In one embodiment, Component A comprises one or more structures selected from the group consisting of:

##STR00190## ##STR00191## ##STR00192##

[0178] wherein R.sup.1 to R.sup.9 each independently represent from mono to maximum number of substitutions they can have, or no substitution; wherein R.sup.1 to R.sup.9 are each 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; and

[0179] wherein each Y.sup.1 is the same or different and is selected from the group consisting of O, S, Se, NR.sup.N and CR′R″; wherein R.sup.N, R′, and R″ are defined above.

Combination with Other Materials

[0180] The materials described herein as useful for a particular layer in an organic light emitting device may be used in combination with a wide variety of other materials present in the device. For example, emissive dopants disclosed herein may be used in conjunction with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes and other layers that may be present. The materials described or referred to below are non-limiting examples of materials that may be useful in combination with the compounds disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that may be useful in combination.

Conductivity Dopants:

[0181] A charge transport layer can be doped with conductivity dopants to substantially alter its density of charge carriers, which will in turn alter its conductivity. The conductivity is increased by generating charge carriers in the matrix material, and depending on the type of dopant, a change in the Fermi level of the semiconductor may also be achieved. Hole-transporting layer can be doped by p-type conductivity dopants and n-type conductivity dopants are used in the electron-transporting layer.

[0182] Non-limiting examples of the conductivity dopants that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: EP01617493, EP01968131, EP2020694, EP2684932, US20050139810, US20070160905, US20090167167, US2010288362, WO06081780, WO2009003455, WO2009008277, WO2009011327, WO2014009310, US2007252140, US2015060804, US20150123047, and US2012146012.

##STR00193##

HIL/HTL:

[0183] A hole injecting/transporting material to be used in the present invention is not particularly limited, and any compound may be used as long as the compound is typically used as a hole injecting/transporting material. Examples of the material include, but are not limited to: a phthalocyanine or porphyrin derivative; an aromatic amine derivative; an indolocarbazole derivative; a polymer containing fluorohydrocarbon; a polymer with conductivity dopants; a conducting polymer, such as PEDOT/PSS; a self-assembly monomer derived from compounds such as phosphonic acid and silane derivatives; a metal oxide derivative, such as 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.

[0184] Examples of aromatic amine derivatives used in HIL or HTL include, but not limit to the following general structures:

##STR00194##

[0185] Each of Ar.sup.1 to Ar.sup.9 is selected from the group consisting of aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene; the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine; and the group consisting of 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Each Ar may be unsubstituted or may be substituted by a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acids, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

[0186] In one aspect, Ar.sup.1 to Ar.sup.9 is independently selected from the group consisting of:

##STR00195##

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.

[0187] Examples of metal complexes used in HIL or HTL include, but are not limited to the following general formula:

##STR00196##

wherein Met is a metal, which can have an atomic weight greater than 40; (Y.sup.101-Y.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.

[0188] In one aspect, (Y.sup.101-Y.sup.102) a is 2-phenylpyridine derivative. In another aspect, (Y.sup.101-Y.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.

[0189] Non-limiting examples of the HIL and HTL materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: CN102702075, DE102012005215, EP01624500, EP01698613, EP01806334, EP01930964, EP01972613, EP01997799, EP02011790, EP02055700, EP02055701, EP1725079, EP2085382, EP2660300, EP650955, JP07-073529, JP2005112765, JP2007091719, JP2008021687, JP2014-009196, KR20110088898, KR20130077473, TW201139402, U.S. Ser. No. 06/517,957, US20020158242, US20030162053, US20050123751, US20060182993, US20060240279, US20070145888, US20070181874, US20070278938, US20080014464, US20080091025, US20080106190, US20080124572, US20080145707, US20080220265, US20080233434, US20080303417, US2008107919, US20090115320, US20090167161, US2009066235, US2011007385, US20110163302, US2011240968, US2011278551, US2012205642, US2013241401, US20140117329, US2014183517, U.S. Pat. Nos. 5,061,569, 5,639,914, WO05075451, WO07125714, WO08023550, WO08023759, WO2009145016, WO2010061824, WO2011075644, WO2012177006, WO2013018530, WO2013039073, WO2013087142, WO2013118812, WO2013120577, WO2013157367, WO2013175747, WO2014002873, WO2014015935, WO2014015937, WO2014030872, WO2014030921, WO2014034791, WO2014104514, WO2014157018.

##STR00197## ##STR00198## ##STR00199## ##STR00200## ##STR00201## ##STR00202## ##STR00203## ##STR00204## ##STR00205## ##STR00206## ##STR00207## ##STR00208## ##STR00209## ##STR00210## ##STR00211## ##STR00212## ##STR00213## ##STR00214## ##STR00215##

EBL:

[0190] An electron blocking layer (EBL) may be used to reduce the number of electrons and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies, and/or longer lifetime, as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and/or higher triplet energy than the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and/or higher triplet energy than one or more of the hosts closest to the EBL interface. In one aspect, the compound used in EBL contains the same molecule or the same functional groups used as one of the hosts described below.

Host:

[0191] The light emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as light emitting material, and may contain a host material using the metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complexes or organic compounds may be used as long as the triplet energy of the host is larger than that of the dopant. Any host material may be used with any dopant so long as the triplet criteria is satisfied.

[0192] Examples of metal complexes used as host are preferred to have the following general formula:

##STR00216##

wherein Met is a metal; (Y.sup.103-Y.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.

[0193] In one aspect, the metal complexes are:

##STR00217##

wherein (O—N) is a bidentate ligand, having metal coordinated to atoms O and N.

[0194] In another aspect, Met is selected from Ir and Pt. In a further aspect, (Y.sup.103-Y.sup.104) is a carbene ligand.

[0195] Examples of other organic compounds used as host are selected from the group consisting of aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene; the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine; and the group consisting of 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Each option within each group may be unsubstituted or may be substituted by a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acids, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

[0196] In one aspect, the host compound contains at least one of the following groups in the molecule:

##STR00218## ##STR00219##

wherein R.sup.101 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acids, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. k is an integer from 0 to 20 or 1 to 20. X.sup.101 to X.sup.108 are independently selected from C (including CH) or N. Z.sup.101 and Z.sup.102 are independently selected from NR.sup.101, O, or S.

[0197] Non-limiting examples of the host materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: EP2034538, EP2034538A, EP2757608, JP2007254297, KR20100079458, KR20120088644, KR20120129733, KR20130115564, TW201329200, US20030175553, US20050238919, US20060280965, US20090017330, US20090030202, US20090167162, US20090302743, US20090309488, US20100012931, US20100084966, US20100187984, US2010187984, US2012075273, US2012126221, US2013009543, US2013105787, US2013175519, US2014001446, US20140183503, US20140225088, US2014034914, U.S. Pat. No. 7,154,114, WO2001039234, WO2004093207, WO2005014551, WO2005089025, WO2006072002, WO2006114966, WO2007063754, WO2008056746, WO2009003898, WO2009021126, WO2009063833, WO2009066778, WO2009066779, WO2009086028, WO2010056066, WO2010107244, WO2011081423, WO2011081431, WO2011086863, WO2012128298, WO2012133644, WO2012133649, WO2013024872, WO2013035275, WO2013081315, WO2013191404, WO2014142472, US20170263869, US20160163995, U.S. Pat. No. 9,466,803,

##STR00220## ##STR00221## ##STR00222## ##STR00223## ##STR00224## ##STR00225## ##STR00226## ##STR00227## ##STR00228## ##STR00229## ##STR00230## ##STR00231## ##STR00232## ##STR00233## ##STR00234## ##STR00235##

Additional Emitters:

[0198] One or more additional emitter dopants may be used in conjunction with the compound of the present disclosure. Examples of the additional emitter dopants are not particularly limited, and any compounds may be used as long as the compounds are typically used as emitter materials. Examples of suitable emitter materials include, but are not limited to, compounds which can produce emissions via phosphorescence, fluorescence, thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence), triplet-triplet annihilation, or combinations of these processes.

[0199] Non-limiting examples of the emitter materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: CN103694277, CN1696137, EB01238981, EP01239526, EP01961743, EP1239526, EP1244155, EP1642951, EP1647554, EP1841834, EP1841834B, EP2062907, EP2730583, JP2012074444, JP2013110263, JP4478555, KR1020090133652, KR20120032054, KR20130043460, TW201332980, U.S. Ser. No. 06/699,599, U.S. Ser. No. 06/916,554, US20010019782, US20020034656, US20030068526, US20030072964, US20030138657, US20050123788, US20050244673, US2005123791, US2005260449, US20060008670, US20060065890, US20060127696, US20060134459, US20060134462, US20060202194, US20060251923, US20070034863, US20070087321, US20070103060, US20070111026, US20070190359, US20070231600, US2007034863, US2007104979, US2007104980, US2007138437, US2007224450, US2007278936, US20080020237, US20080233410, US20080261076, US20080297033, US200805851, US2008161567, US2008210930, US20090039776, US20090108737, US20090115322, US20090179555, US2009085476, US2009104472, US20100090591, US20100148663, US20100244004, US20100295032, US2010102716, US2010105902, US2010244004, US2010270916, US20110057559, US20110108822, US20110204333, US2011215710, US2011227049, US2011285275, US2012292601, US20130146848, US2013033172, US2013165653, US2013181190, US2013334521, US20140246656, US2014103305, U.S. Pat. Nos. 6,303,238, 6,413,656, 6,653,654, 6,670,645, 6,687,266, 6,835,469, 6,921,915, 7,279,704, 7,332,232, 7,378,162, 7,534,505, 7,675,228, 7,728,137, 7,740,957, 7,759,489, 7,951,947, 8,067,099, 8,592,586, 8,871,361, WO06081973, WO06121811, WO07018067, WO07108362, WO07115970, WO07115981, WO08035571, WO2002015645, WO2003040257, WO2005019373, WO2006056418, WO2008054584, WO2008078800, WO2008096609, WO2008101842, WO2009000673, WO2009050281, WO2009100991, WO2010028151, WO2010054731, WO2010086089, WO2010118029, WO2011044988, WO2011051404, WO2011107491, WO2012020327, WO2012163471, WO2013094620, WO2013107487, WO2013174471, WO2014007565, WO2014008982, WO2014023377, WO2014024131, WO2014031977, WO2014038456, WO2014112450.

##STR00236## ##STR00237## ##STR00238## ##STR00239## ##STR00240## ##STR00241## ##STR00242## ##STR00243## ##STR00244## ##STR00245## ##STR00246## ##STR00247## ##STR00248## ##STR00249## ##STR00250## ##STR00251## ##STR00252## ##STR00253## ##STR00254## ##STR00255## ##STR00256## ##STR00257## ##STR00258## ##STR00259## ##STR00260## ##STR00261## ##STR00262## ##STR00263## ##STR00264##

HBL:

[0200] A hole blocking layer (HBL) may be used to reduce the number of holes and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies and/or longer lifetime as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and/or higher triplet energy than the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and/or higher triplet energy than one or more of the hosts closest to the HBL interface.

[0201] In one aspect, compound used in HBL contains the same molecule or the same functional groups used as host described above.

[0202] In another aspect, compound used in HBL contains at least one of the following groups in the molecule:

##STR00265##

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:

[0203] 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.

[0204] In one aspect, compound used in ETL contains at least one of the following groups in the molecule:

##STR00266##

wherein R.sup.101 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acids, ether, 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.

[0205] In another aspect, the metal complexes used in ETL contains, but not limit to the following general formula:

##STR00267##

wherein (O—N) or (N—N) 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.

[0206] Non-limiting examples of the ETL materials that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: CN103508940, EP01602648, EP01734038, EP01956007, JP2004-022334, JP2005149918, JP2005-268199, KR0117693, KR20130108183, US20040036077, US20070104977, US2007018155, US20090101870, US20090115316, US20090140637, US20090179554, US2009218940, US2010108990, US2011156017, US2011210320, US2012193612, US2012214993, US2014014925, US2014014927, US20140284580, U.S. Pat. Nos. 6,656,612, 8,415,031, WO2003060956, WO2007111263, WO2009148269, WO2010067894, WO2010072300, WO2011074770, WO2011105373, WO2013079217, WO2013145667, WO2013180376, WO2014104499, WO2014104535,

##STR00268## ##STR00269## ##STR00270## ##STR00271## ##STR00272## ##STR00273## ##STR00274## ##STR00275## ##STR00276## ##STR00277## ##STR00278##

Charge Generation Layer (CGL)

[0207] In tandem or stacked OLEDs, the CGL plays an essential role in the performance, which is composed of an n-doped layer and a p-doped layer for injection of electrons and holes, respectively. Electrons and holes are supplied from the CGL and electrodes. The consumed electrons and holes in the CGL are refilled by the electrons and holes injected from the cathode and anode, respectively; then, the bipolar currents reach a steady state gradually. Typical CGL materials include n and p conductivity dopants used in the transport layers.

[0208] In any above-mentioned compounds used in each layer of the OLED device, the hydrogen atoms can be partially or fully deuterated. Thus, any specifically listed substituent, such as, without limitation, methyl, phenyl, pyridyl, etc. may be undeuterated, partially deuterated, and fully deuterated versions thereof. Similarly, classes of substituents such as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc. also may be undeuterated, partially deuterated, and fully deuterated versions thereof.

Experimental

[0209] ##STR00279##

[0210] Intermediate-1 is synthesized according to reported procedure (Synth. Met. 2001, 122, 485-493). Compound 251788 is obtained by deprotection of Intermediate-1 by TBAF, followed by transition metal catalyzed C—N coupling between Intermediate-1 and carbazole and oxidation in the presence of PbO.sub.2 (J. Am. Chem. Soc. 2009, 131, 3700-3712).

##STR00280##

[0211] Intermediate-2 is synthesized according to reported procedure (PCT Int. Appl., 2013022046). Compound 251805 is obtained by transition metal catalyzed C—N coupling between Intermediate-1 and carbazole, followed by a literature oxidation procedure in the presence of MnO.sub.2 (J. Phys. Chem. A, 2016, 120, 2841-2853).

[0212] Time Dependent Density Functional Theory (TDDFT) calculations were used to predict the emission properties of select compounds described herein. The emission wavelength was calculated within the Gaussian software package using the B3LYP-D3 hybrid functional set and 6-31G* basis set, and derived from the relative energy of the first vertical excited doublet state compared to the corresponding ground state. A continuum solvent model was applied to simulate tetrahydrofuran solvent. The DFT calculations are summarized in Table 2.

[0213] The DFT calculations demonstrate that how substituent effects may be used to tune the emission properties of stable radical emitters over a wide range of wavelengths. For example, the α-nitronyl nitroxide compounds 1-4 vary over an emission range of 518-579 nm (green to yellow). These are useful wavelengths for the fabrication of organic light-emitting devices. Compounds 5-19 are all constructed around the triphenylmethyl radical, and exhibit emission over a very wide range of wavelengths—from yellow (e.g. compound 5) to red (e.g. compound 10) to near IR (e.g. compound 17)—depending on substitution. It may therefore be anticipated that these compounds will find application in organic light-emitting devices, including night-vision and virtual reality displays.

TABLE-US-00002 TABLE 2 Emission Representative Wavelength Compound No. Structure (nm) 1 [00281] embedded image 528 2 [00282] 544 3 [00283] 579 4 [00284] 518 5 [00285] 581 6 [00286] 1081 7 [00287] 610 8 [00288] 1015 9 [00289] 1279 10 [00290] 644 11 [00291] 687 12 [00292] 693 13 [00293] 1170 14 [00294] 1322 15 [00295] 670 16 [00296] 769 17 [00297] 982 18 [00298] embedded image 1485 19 [00299] 771

[0214] 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.

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