Organic electroluminescent materials and devices
10811618 ยท 2020-10-20
Assignee
Inventors
Cpc classification
H10K85/381
ELECTRICITY
C09K11/025
CHEMISTRY; METALLURGY
International classification
C09K11/02
CHEMISTRY; METALLURGY
Abstract
Metal complexes containing heteroaryl and its analogues as ligands are disclosed in this application. These compounds may be useful as charge transport materials in OLEDs.
Claims
1. A compound comprising a ligand L.sub.A having the formula: ##STR00122## wherein X.sup.1 is selected from the group consisting of NR, CRR, and SiRR, wherein L.sub.A is coordinated to a metal M selected from the group consisting of Li, Be, Mg, Al, Ga, and Zn; wherein L.sub.A is optionally linked with other ligands to comprise a tridentate to possible maximum dentate ligand; wherein M is optionally coordinated to other ligands; wherein at least one pair of adjacent Z.sup.1 to Z.sup.3, or Z.sup.4 to Z.sup.6 are carbon atoms of which R.sup.1 or R.sup.2 attached thereto form a di-substitution having the following formula and are fused to ring A or B; ##STR00123## wherein the wave lines indicate bonds to ring A or B; wherein X.sup.2 is selected from the group consisting of NR, CRR, and SiRR; wherein Z.sup.1 to Z.sup.6 and Z.sup.11 to Z.sup.14 are each independently selected from the group consisting of carbon and nitrogen; wherein R.sup.1, R.sup.2, and R.sup.4 each independently represent a mono to possible maximum number of substitution, or no substitution; wherein R.sup.1, R.sup.2, R.sup.4, R, and R are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein any two adjacent substituents are optionally joined to form a ring.
2. The compound of claim 1, wherein the ligand L.sub.A is selected from the group consisting of: ##STR00124##
3. The compound of claim 1, wherein Z.sup.1 to Z.sup.6 and Z.sup.11 to Z.sup.14 are each a carbon atom.
4. The compound of claim 1, wherein at least one of Z.sup.1 to Z.sup.6 and Z.sup.11 to Z.sup.14 is nitrogen atom.
5. The compound of claim 1, wherein one of Z.sup.1 to Z.sup.6 and Z.sup.11 to Z.sup.14 is nitrogen atom, and the remaining Z.sup.1 to Z.sup.14 are carbon atoms.
6. The compound of claim 1, wherein each six-membered ring in the ligand L.sub.A has no more than one nitrogen atom.
7. The compound of claim 1, wherein the compound is selected from the group consisting of LiL.sub.A, Be(L.sub.A).sub.2, Mg(L.sub.A).sub.2, Al(L.sub.A).sub.3, Ga(L.sub.A).sub.3, and Zn(L.sub.A).sub.2.
8. The compound of claim 1, wherein the compound is heteroleptic.
9. The compound of claim 1, wherein the compound is selected from the group consisting of: Compound 1, wherein X.sup.1 is O; Compound 4, wherein X.sup.1 is O; Compound 2, wherein X.sup.1 is S; Compound 5, wherein X.sup.1 is S; Compound 3, wherein X.sup.1 is Se; Compound 6, wherein X.sup.1 is Se; Compound 7, wherein X.sup.1 is O; Compound 10, wherein X.sup.1 is O; Compound 8, wherein X.sup.1 is S; Compound 11, wherein X.sup.1 is S; Compound 9, wherein X.sup.1 is Se; Compound 12, wherein X.sup.1 is Se; Compound 13, wherein X.sup.1 is O; Compound 16, wherein X.sup.1 is O; Compound 14, wherein X.sup.1 is S; Compound 17, wherein X.sup.1 is S; Compound 15, wherein X.sup.1 is Se; Compound 18, wherein X.sup.1 is Se; Compound 19, wherein X.sup.1 is O; Compound 22, wherein X.sup.1 is O; Compound 20, wherein X.sup.1 is S; Compound 23, wherein X.sup.1 is S; Compound 21, wherein X.sup.1 is Se; Compound 24, wherein X.sup.1 is Se; Compound 25, wherein X.sup.1 is O; Compound 28, wherein X.sup.1 is O; Compound 26, wherein X.sup.1 is S; Compound 29, wherein X.sup.1 is S; TABLE-US-00003 ID Structure n M X.sup.1 X.sup.2 Compound 107 Compound 108 Compound 109 Compound 113 Compound 114 Compound 115 Compound 119 Compound 120 Compound 121
10. An organic light emitting device (OLED) comprising: an anode; a cathode; and a first organic layer, disposed between the anode and the cathode, comprising a compound comprising a ligand L.sub.A having the formula: ##STR00157## wherein X.sup.1 is selected from the group consisting of NR, CRR, and SiRR, wherein L.sub.A is coordinated to a metal M selected from the group consisting of Li, Be, Mg, Al, Ga, and Zn; wherein L.sub.A is optionally linked with other ligands to comprise a tridentate to possible maximum dentate ligand; wherein M is optionally coordinated to other ligands; wherein at least one pair of adjacent Z.sup.1 to Z.sup.3, or Z.sup.4 to Z.sup.6 are carbon atoms of which R.sup.1 or R.sup.2 attached thereto form a di-substitution having the following formula and are fused to ring A or B; ##STR00158## wherein the wave lines indicate bonds to ring A or B; wherein X.sup.2 is selected from the group consisting of NR, CRR, and SiRR; wherein Z.sup.1 to Z.sup.6 and Z.sup.11 to Z.sup.14 are each independently selected from the group consisting of carbon and nitrogen; wherein R.sup.1, R.sup.2, and R.sup.4 each independently represent a mono to possible maximum number of substitution, or no substitution; wherein R.sup.1, R.sup.2, R.sup.4, R, and R are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein any two adjacent substituents are optionally joined to form a ring.
11. The OLED of claim 10, wherein the first organic layer is an electron injecting layer.
12. The OLED of claim 10, wherein the OLED comprises a second organic layer, wherein the second organic layer is an emitting layer comprising a phosphorescent emissive dopant; wherein the emissive dopant is a transition metal complex having at least one ligand or part of the ligand if the ligand is more than bidentate selected from the group consisting of: ##STR00159## wherein each X.sup.1 to X.sup.13 are independently selected from the group consisting of carbon and nitrogen; wherein X is selected from the group consisting of BR, NR, PR, O, S, Se, CO, SO, SO.sub.2, CRR, SiRR, and GeRR; wherein R and R are optionally fused or joined to form a ring; wherein each R.sub.a, R.sub.b, R.sub.c, and R.sub.d may represent from mono substitution to the possible maximum number of substitution, or no substitution; wherein R, R, R.sub.a, R.sub.b, R.sub.c, and R.sub.d 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 any two adjacent substituents of R.sub.a, R.sub.b, R.sub.c, and R.sub.d are optionally fused or joined to form a ring or form a multidentate ligand.
13. The OLED of claim 10, wherein the OLED is incorporated into a device selected from the group consisting of a consumer product, an electronic component module, and a lighting panel.
14. A formulation comprising a compound according to claim 1.
15. A compound comprising a ligand L.sub.A having the formula: ##STR00160## wherein L.sub.A is coordinated to a metal M selected from the group consisting of Li, Be, Mg, Al, Ga, and Zn; wherein L.sub.A is optionally linked with other ligands to comprise a tridentate to possible maximum dentate ligand; wherein M is optionally coordinated to other ligands; wherein Z.sup.1 to Z.sup.10 are each independently selected from the group consisting of carbon and nitrogen; wherein R.sup.1 to R.sup.3 each independently represent a mono to possible maximum number of substitution, or no substitution; wherein R.sup.1 to R.sup.3 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein any two adjacent substituents are optionally joined to form a ring.
16. The compound of claim 15, wherein at least one of Z.sup.1 to Z.sup.10 is nitrogen atom.
17. The compound of claim 15, wherein the compound is selected from the group consisting of: TABLE-US-00004 Structure ID n M Compound 31 Compound 32 Compound 33 Compound 34 Compound 35
18. An organic light emitting device (OLED) comprising: an anode; a cathode; and a first organic layer, disposed between the anode and the cathode, comprising a compound according to claim 15.
19. The OLED of claim 15, wherein the OLED is incorporated into a device selected from the group consisting of a consumer product, an electronic component module, and a lighting panel.
20. A formulation comprising a compound according to claim 15.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
DETAILED DESCRIPTION
(3) 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.
(4) 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.
(5) 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.
(6)
(7) 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.
(8)
(9) The simple layered structure illustrated in
(10) 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
(11) Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties, organic vapor phase deposition (OVPD), such as described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety, and deposition by organic vapor jet printing (OVJP), such as described in U.S. Pat. No. 7,431,968, which is incorporated by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, and patterning associated with some of the deposition methods such as ink-jet and OVJD. Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having 20 carbons or more may be used, and 3-20 carbons is a preferred range. Materials with asymmetric structures may have better solution processibility than those having symmetric structures, because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.
(12) 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.
(13) Devices fabricated in accordance with embodiments of the invention can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into a variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include display screens, lighting devices such as discrete light source devices or lighting panels, etc. that can be utilized by the end-user product manufacturers. Such electronic component modules can optionally include the driving electronics and/or power source(s). Devices fabricated in accordance with embodiments of the invention can be incorporated into a wide variety of consumer products that have one or more of the electronic component modules (or units) incorporated therein. Such consumer products would include any kind of products that include one or more light source(s) and/or one or more of some type of visual displays. Some examples of such consumer products include flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully or partially transparent displays, flexible displays, laser printers, telephones, cell phones, tablets, phablets, personal digital assistants (PDAs), wearable device, laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, virtual reality or augmented reality displays, vehicles, a large area wall, theater or stadium screen, or a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as 18 degrees C. to 30 degrees C., and more preferably at room temperature (20-25 degrees C.), but could be used outside this temperature range, for example, from 40 degree C. to +80 degree C.
(14) 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.
(15) The term halo, halogen, or halide as used herein includes fluorine, chlorine, bromine, and iodine.
(16) The term alkyl as used herein contemplates both straight and branched chain alkyl radicals. Preferred alkyl groups are those containing from one to fifteen carbon atoms and includes methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, and the like. Additionally, the alkyl group may be optionally substituted.
(17) The term cycloalkyl as used herein contemplates cyclic alkyl radicals. Preferred cycloalkyl groups are those containing 3 to 10 ring carbon atoms and includes cyclopropyl, cyclopentyl, cyclohexyl, adamantyl, and the like. Additionally, the cycloalkyl group may be optionally substituted.
(18) The term alkenyl as used herein contemplates both straight and branched chain alkene radicals. Preferred alkenyl groups are those containing two to fifteen carbon atoms. Additionally, the alkenyl group may be optionally substituted.
(19) The term alkynyl as used herein contemplates both straight and branched chain alkyne radicals. Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group may be optionally substituted.
(20) The terms aralkyl or arylalkyl as used herein are used interchangeably and contemplate an alkyl group that has as a substituent an aromatic group. Additionally, the aralkyl group may be optionally substituted.
(21) The term heterocyclic group as used herein contemplates aromatic and non-aromatic cyclic radicals. Hetero-aromatic cyclic radicals also means heteroaryl. Preferred hetero-non-aromatic cyclic groups are those containing 3 to 7 ring atoms which includes at least one hetero atom, and includes cyclic amines such as morpholino, piperdino, pyrrolidino, and the like, and cyclic ethers, such as tetrahydrofuran, tetrahydropyran, and the like. Additionally, the heterocyclic group may be optionally substituted.
(22) The term aryl or aromatic group as used herein contemplates single-ring groups and polycyclic ring systems. The polycyclic rings may have two or more rings in which two carbons are common to two adjoining rings (the rings are fused) wherein at least one of the rings is aromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls. Preferred aryl groups are those containing six to thirty carbon atoms, preferably six to twenty carbon atoms, more preferably six to twelve carbon atoms. Especially preferred is an aryl group having six carbons, ten carbons or twelve carbons. Suitable aryl groups include phenyl, biphenyl, triphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene, preferably phenyl, biphenyl, triphenyl, triphenylene, fluorene, and naphthalene. Additionally, the aryl group may be optionally substituted.
(23) The term heteroaryl as used herein contemplates single-ring hetero-aromatic groups that may include from one to five heteroatoms. The term heteroaryl also includes polycyclic hetero-aromatic systems having two or more rings in which two atoms are common to two adjoining rings (the rings are fused) wherein at least one of the rings is a heteroaryl, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl, heterocycles, and/or heteroaryls. Preferred heteroaryl groups are those containing three to thirty carbon atoms, preferably three to twenty carbon atoms, more preferably three to twelve carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, 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 may be optionally substituted.
(24) The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group, aryl, and heteroaryl may be unsubstituted or may be substituted with one or more substituents selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
(25) As used herein, substituted indicates that a substituent other than H is bonded to the relevant position, such as carbon. Thus, for example, where R.sup.1 is mono-substituted, then one R.sup.1 must be other than H. Similarly, where R.sup.1 is di-substituted, then two of R.sup.1 must be other than H. Similarly, where R.sup.1 is unsubstituted, R.sup.1 is hydrogen for all available positions.
(26) The aza designation in the fragments described herein, i.e. aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more of the CH groups in the respective fragment can be replaced by a nitrogen atom, for example, and without any limitation, azatriphenylene encompasses both dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. One of ordinary skill in the art can readily envision other nitrogen analogs of the aza-derivatives described above, and all such analogs are intended to be encompassed by the terms as set forth herein.
(27) 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.
(28) It is hypothesized that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistics limit through delayed fluorescence. As described 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).
(29) On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the thermal population between the triplet states and the singlet excited states. Compounds that are capable of generating E-type delayed fluorescence are required to have very small singlet-triplet gaps. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A distinctive feature of TADF is that the delayed component increases as temperature rises due to the increased thermal energy. If the reverse intersystem crossing rate is fast enough to minimize the non-radiative decay from the triplet state, the fraction of back populated singlet excited states can potentially reach 75%. The total singlet fraction can be 100%, far exceeding the spin statistics limit for electrically generated excitons.
(30) 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 (E.sub.S-T). Organic, non-metal containing, donor-acceptor luminescent materials may be able to achieve this. The emission in these materials is often characterized as a donor-acceptor charge-transfer (CT) type emission. The spatial separation of the HOMO and LUMO in these donor-acceptor type compounds often results in small E.sub.S-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.
(31) In one aspect, the present invention includes novel metal complexes comprising a heteroaryl and analogues as ligands. These compounds have appropriate charge transport properties and may be useful as charge transport materials in electroluminescent devices.
Compounds of the Invention
(32) In one aspect, the present invention includes a compound comprising a ligand L.sub.A having the formula:
(33) ##STR00005##
(34) wherein X.sup.1 is selected from the group consisting of O, S, Se, NR, CRR, SiRR, and
(35) ##STR00006##
(36) wherein L.sub.A is coordinated to a metal M selected from the group consisting of Li, Be, Mg, Al, Ga, and Zn;
(37) wherein L.sub.A is optionally linked with other ligands to comprise a tridentate to possible maximum dentate ligand;
(38) wherein M is optionally coordinated to other ligands;
(39) wherein when X.sup.1 is selected from the group consisting of O, S, and Se; then M is Li;
(40) wherein when X.sup.1 is selected from the group consisting of NR, CRR, SiRR; then at least one pair of adjacent Z.sup.1 to Z.sup.3, or Z.sup.4 to Z.sup.6 are carbon atoms of which R.sup.1 or R.sup.2 attached thereto form a di-substitution having the following formula and are fused to ring A or B;
(41) ##STR00007##
(42) wherein the wave lines indicate bonds to ring A or B;
(43) wherein X.sup.2 is selected from the group consisting of O, S, Se, NR, CRR, and SiRR;
(44) wherein Z.sup.1 to Z.sup.14 are each independently selected from the group consisting of carbon and nitrogen;
(45) wherein R.sup.1 to R.sup.4 each independently represent a mono to possible maximum number of substitution, or no substitution;
(46) wherein R.sup.1 to R.sup.4, R, and R are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein any two adjacent substituents are optionally joined to form a ring.
(47) In one embodiment, X.sup.1 is selected from the group consisting of O, S, and Se. In another embodiment, X.sup.1 is selected from the group consisting of NR, CRR, and SiRR.
(48) In one embodiment, the ligand L.sub.A is:
(49) ##STR00008##
(50) In one embodiment, the ligand L.sub.A is selected from the group consisting of:
(51) ##STR00009##
(52) In one embodiment, Z.sup.1 to Z.sup.14 are each a carbon atom. In another embodiment, at least one of Z.sup.1 to Z.sup.14 is nitrogen atom. In another embodiment, one of Z.sup.1 to Z.sup.14 is nitrogen atom, and the remaining Z.sup.1 to Z.sup.14 are carbon atoms.
(53) In one embodiment, each six-membered ring in the ligand L.sub.A has no more than one nitrogen atom.
(54) In one embodiment, the compound is selected from the group consisting of LiL.sub.A, Be(L.sub.A).sub.2, Mg(L.sub.A).sub.2, Al(L.sub.A).sub.3, Ga(L.sub.A).sub.3, and Zn(L.sub.A).sub.2. In another embodiment, the compound is heteroleptic.
(55) In one embodiment, the compound is selected from the group consisting of:
(56) TABLE-US-00001
(57) TABLE-US-00002 Structure ID n M Compound 31 Compound 32 Compound 33 Compound 34 Compound 35
(58) According to another aspect of the present disclosure, an OLED is also provided. The OLED includes an anode, a cathode, and an organic layer disposed between the anode and the cathode. In one embodiment, the OLED includes an anode, a cathode, and a first organic layer disposed between the anode and the cathode. The organic layer may include a host and one or more emitter dopants.
(59) The emitter dopants can be phosphorescent dopants. The organic layer can include a compound comprising a ligand L.sub.A, and its variations as described herein as a host.
(60) In one embodiment, the organic layer is an emissive layer and the compound comprising a ligand L.sub.A is a host. In another embodiment, the organic layer is a blocking layer and the compound comprising a ligand L.sub.A is a blocking material in the organic layer. In another embodiment, the organic layer is a transporting layer and the compound comprising a ligand L.sub.A is a transporting material in the organic layer. In another embodiment, the first organic layer is an electron injecting layer
(61) In one embodiment, the organic layer further comprises a phosphorescent emissive dopant; wherein the emissive dopant is a transition metal complex having at least one ligand or part of the ligand if the ligand is more than bidentate selected from the group consisting of:
(62) ##STR00063## ##STR00064## ##STR00065## ##STR00066##
(63) wherein each X.sup.1 to X.sup.13 are independently selected from the group consisting of carbon and nitrogen;
(64) wherein X is selected from the group consisting of BR, NR, PR, O, S, Se, CO, SO, SO.sub.2, CRR, SiRR, and GeRR;
(65) wherein R and R are optionally fused or joined to form a ring;
(66) wherein each R.sub.a, R.sub.b, R.sub.c, and R.sub.d may represent from mono substitution to the possible maximum number of substitution, or no substitution;
(67) wherein R, R, R.sub.a, R.sub.b, R.sub.c, and R.sub.d 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
(68) wherein any two adjacent substituents of R.sub.a, R.sub.b, R.sub.c, and R.sub.d are optionally fused or joined to form a ring or form a multidentate ligand.
(69) In one embodiment, the OLED comprises a second organic layer, wherein the second organic layer is an emitting layer comprising a phosphorescent emissive dopant.
(70) The OLED can be incorporated into one or more of a consumer product, an electronic component module, and a lighting panel.
(71) In yet another aspect of the present disclosure, a formulation comprising a compound comprising a ligand L.sub.A is described. The formulation can include one or more components selected from the group consisting of a solvent, a host, a hole injection material, hole transport material, and an electron transport layer material, disclosed herein.
(72) Combination with Other Materials
(73) 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.
(74) Conductivity Dopants:
(75) 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.
(76) Non-limiting examples of the conductivity dopants that may be used in an OLED in combination with materials disclosed herein are exemplified below together with references that disclose those materials: EP01617493, EP01968131, EP2020694, EP2684932, US20050139810, US20070160905, US20090167167, US2010288362, WO06081780, WO2009003455, WO2009008277, WO2009011327, WO2014009310, US2007252140, US2015060804 and US2012146012.
(77) ##STR00067## ##STR00068## ##STR00069##
HIL/HTL:
(78) 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.
(79) Examples of aromatic amine derivatives used in HIL or HTL include, but are not limited to the following general structures:
(80) ##STR00070##
(81) 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, 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.
(82) In one aspect, Ar.sup.1 to Ar.sup.9 is independently selected from the group consisting of:
(83) ##STR00071##
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.
(84) Examples of metal complexes used in HIL or HTL include, but are not limited to the following general formula:
(85) ##STR00072##
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.
(86) In one aspect, (Y.sup.101-Y.sup.102) is a 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.
(87) 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.
(88) ##STR00073## ##STR00074## ##STR00075## ##STR00076## ##STR00077## ##STR00078## ##STR00079## ##STR00080## ##STR00081## ##STR00082## ##STR00083## ##STR00084## ##STR00085## ##STR00086##
EBL:
(89) 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.
(90) Additional Hosts:
(91) The light emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as light emitting dopant material, and may contain one or more additional host materials 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.
(92) Examples of metal complexes used as host are preferred to have the following general formula:
(93) ##STR00087##
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.
(94) In one aspect, the metal complexes are:
(95) ##STR00088##
wherein (ON) is a bidentate ligand, having metal coordinated to atoms O and N.
(96) In another aspect, Met is selected from Ir and Pt. In a further aspect, (Y.sup.103-Y.sup.104) is a carbene ligand.
(97) Examples of other organic compounds used as additional host are selected from the group consisting of aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; group consisting aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine; and group consisting 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Wherein each group is further substituted by a substituent selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
(98) In one aspect, host compound contains at least one of the following groups in the molecule:
(99) ##STR00089## ##STR00090##
wherein R.sup.101 to R.sup.107 is independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. k is an integer from 0 to 20 or 1 to 20; k is an integer from 0 to 20. X.sup.101 to X.sup.108 is selected from C (including CH) or N. Z.sup.101 and Z.sup.102 is selected from NR.sup.101, O, or S.
(100) Non-limiting examples of the additional host materials that may be used in an OLED in combination with the host compound 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,
(101) ##STR00091## ##STR00092## ##STR00093## ##STR00094## ##STR00095## ##STR00096## ##STR00097## ##STR00098## ##STR00099## ##STR00100##
Emitter:
(102) An emitter example is not particularly limited, and any compound may be used as long as the compound is typically used as an emitter material. 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.
(103) 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, WO007115970, 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,
(104) ##STR00101## ##STR00102## ##STR00103## ##STR00104## ##STR00105## ##STR00106## ##STR00107## ##STR00108## ##STR00109## ##STR00110##
HBL:
(105) 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.
(106) In one aspect, compound used in HBL contains the same molecule or the same functional groups used as host described above.
(107) In another aspect, compound used in HBL contains at least one of the following groups in the molecule:
(108) ##STR00111##
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:
(109) 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.
(110) In one aspect, compound used in ETL contains at least one of the following groups in the molecule:
(111) ##STR00112##
wherein R.sup.101 is selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. Ar.sup.1 to Ar.sup.3 has the similar definition as Ar's mentioned above. k is an integer from 1 to 20. X.sup.101 to X.sup.108 is selected from C (including CH) or N.
(112) In another aspect, the metal complexes used in ETL include, but are not limited to the following general formula:
(113) ##STR00113##
wherein (ON) or (NN) is a bidentate ligand, having metal coordinated to atoms O, N or N, N; L.sup.101 is another ligand; k is an integer value from 1 to the maximum number of ligands that may be attached to the metal.
(114) 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,
(115) ##STR00114## ##STR00115## ##STR00116## ##STR00117## ##STR00118##
Charge Generation Layer (CGL)
(116) 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.
(117) In any above-mentioned compounds used in each layer of the OLED device, the hydrogen atoms can be partially or fully deuterated. Thus, any specifically listed substituent, such as, without limitation, methyl, phenyl, pyridyl, etc. encompasses undeuterated, partially deuterated, and fully deuterated versions thereof. Similarly, classes of substituents such as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc. also encompass undeuterated, partially deuterated, and fully deuterated versions thereof.
EXPERIMENTAL
Synthesis of Compound 1
(118) ##STR00119##
(119) Into a solution of benzofuro[3,2-b]pyridin-9-ol (18.5 g, 100 mol) in methanol is added LiOH hydrate (6.3 g, 150 mmol). The reaction mixture is stirred at room temperature for 24 hours. After quenching with water, the reaction mixture is extracted with ether, dried over MgSO.sub.4. Upon evaporation of the solvent, the crude product is further purified by recrystallization to yield Compound 1 as a solid.
Synthesis of Compound 557
(120) ##STR00120##
(121) Into a degassed solution of 7,12-dihydropyrido[3,2-b:5,4-b]diindol-4-ol (5.49 g, 20 mmol), Phenyl iodide (6.15 g, 30 mmol), K.sub.2CO.sub.3 (8.3 g, 60 mmol) in dimethylformamide are added CuI (0.2 g, 1 mmol) and 1,2-diaminocyclohexane (0.45 g, 4 mmol). The reaction mixture is refluxed under nitrogen for 24 h. After cooling to room temperature, the solid is removed by filtration and the filtrate is concentrated. The crude product is purified by column chromatography on silica gel with heptane/ethyl acetate as eluent to yield 7,12-diphenyl-7,12-dihydropyrido[3,2-b: 5,4-b]diindol-4-ol as a solid.
(122) ##STR00121##
(123) Into a solution of 7,12-diphenyl-7,12-dihydropyrido[3,2-b:5,4-b]diindol-4-ol (4.25 g, 10 mol) in methanol and dimethylformamide is added LiOH hydrate (0.63 g, 15 mmol). The reaction mixture is stirred at room temperature for 24 hours. After quenching with water, the reaction mixture is extracted with ether, dried over MgSO.sub.4. Upon evaporation of the solvent, the crude product is further purified by recrystallization to yield Compound 557 as a solid.
(124) 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.