Organic electroluminescent materials and devices

Abstract

The present application relates to organic electroluminescent materials and devices. An OLED configuration is disclosed which, despite containing an exciplex having an emission spectrum redder than that of an emitter, the emission from the exciplex is suppressed so that the overall OLED emission spectrum is still dominated by the emission of the emitter.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a continuation-in-part of U.S. patent application No. 16 / 683,507, filed on November 14, 2019, which is also a pending application. The patent application claims priority to U.S. Provisional Application No. 62 / 772,403, filed on November 28, 2018, under 35 U.S.C. §119(e), the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to organometallic compounds and formulations and various uses thereof, including as emitters in devices such as organic light emitting diodes and related electronic devices. Background Art

[0004] Optoelectronic devices utilizing organic materials are becoming increasingly popular for a variety of reasons. Many materials used to make the devices are relatively inexpensive, so organic optoelectronic devices have the potential to have cost advantages over inorganic devices. In addition, the inherent properties of organic materials (e.g., their flexibility) can make them more suitable for specific applications, such as manufacturing on flexible substrates. Examples of organic optoelectronic devices include organic light emitting diodes / devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials can have performance advantages over conventional materials.

[0005] OLEDs utilize organic thin films that emit light when a voltage is applied across the device. OLEDs are becoming an increasingly attractive technology for use in applications such as flat panel displays, lighting, and backlighting.

[0006] One application of phosphorescent emitting molecules is full-color displays. Industry standards for such displays require pixels that are suitable for emitting specific colors (called "saturated" colors). Specifically, these standards require saturated red, green, and blue pixels. Alternatively, OLEDs can be designed to emit white light. In conventional liquid crystal displays, an absorption filter is used to filter the emission from a white backlight to produce red, green, and blue emissions. The same technology can also be used for OLEDs. White OLEDs can be single-emission layer (EML) devices or stacked structures. Color can be measured using CIE coordinates well known in the art. Summary of the invention

[0007] An organic light-emitting device (OLED) is disclosed, which includes an anode, a cathode, and an organic emission layer disposed between the anode and the cathode, wherein the organic emission layer includes a first host material having a highest occupied molecular orbital (HOMO) energy and a lowest unoccupied molecular orbital (LUMO) energy, and an emitter material having a HOMO energy and a LUMO energy. The emitter is selected from the group consisting of: a phosphorescent metal complex and a delayed fluorescent emitter. The emitter and the host material in the organic emission layer satisfy the following conditions: a≤E T -ΔE≤b; where E T is the triplet energy T1 of the emitter, which is the lowest T1 energy among all materials in the organic emission layer; ΔE is the energy gap between the high HOMO energy and the low LUMO energy; wherein a is 0.00 to 0.15 eV, and b is 0.05 to 0.45 eV; and wherein the emission spectrum of the OLED is at least 95% similar to the emission spectrum of the OLED whose organic emission layer consists of the first emitter and the inert host. "High HOMO energy" is defined as the highest HOMO energy among all materials in the organic emission layer, and "low LUMO energy" is defined as the lowest LUMO energy among all materials in the organic emission layer.

[0008] A consumer product including the OLED is also disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An organic light emitting device is shown.

[0010] Figure 2 An inverted organic light-emitting device without a separate electron transport layer is demonstrated.

[0011] Figure 3 Curves showing measured photoluminescence intensities (PL) of emitter 1 compound and emitter 2 compound doped in host compounds 5 and 3, respectively, where both spectra are normalized to 1 and shifted to a peak wavelength of 468 nm.

[0012] Figure 4 Plot showing the absolute value of the difference in PL spectra, where the spectra are normalized to 1 and shifted to a peak wavelength of 468 nm between 2 films: one film of an emitter doped at 12 vol% in host compound 3; and a second film of the same emitter doped at 12 vol% in host compound 5. The difference between the two films is plotted for Emitter 1 and Emitter 2.

[0013] Figure 5Plots showing the normalized and shifted PL spectrum of emitter 1 (12 vol%) doped in host compound 5 and the normalized and shifted EL spectrum of emitter 1 (12 vol%) doped in a host that is a mixture of compound 5 and compound 4 (60 vol% compound 4).

[0014] Figure 6 Normalized and shifted EL spectra of emitter 1 doped in four different mixtures of compound 5 with compounds 1, 2, 3 and 4 are shown. DETAILED DESCRIPTION

[0015] Figure 1 An organic light-emitting device 100 is shown. The figures are not necessarily drawn to scale. The 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 emission 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 blocking layer 170. The cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. The device 100 can be manufactured by depositing the described layers in sequence. The properties and functions of these different layers and example materials are described in more detail in US 7,279,704, columns 6-10, which is incorporated by reference.

[0016] More examples of each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated by reference in its entirety. Examples of luminescent and host materials are disclosed in U.S. Patent 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. Patent Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entirety, disclose examples of cathodes including composite cathodes having a thin layer of a metal (e.g., Mg:Ag) with an overlying transparent, conductive, sputter-deposited ITO layer. The theory and use of barrier layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are incorporated by reference in their entirety. 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 can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated by reference in its entirety.

[0017] Figure 2 An inverted OLED 200 is shown. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole transport layer 225, and an anode 230. Device 200 can be manufactured by depositing the layers in order. Because the most common OLED configuration has a cathode disposed above the anode, and device 200 has cathode 215 disposed below anode 230, device 200 can be referred to as an "inverted" OLED. Materials similar to those described with respect to device 100 can be used in the corresponding layers of device 200. Figure 2 An example is provided of how some layers may be omitted from the structure of device 100 .

[0018] Figure 1 and 2The simple layered structures described in are provided by way of non-limiting examples, and it should be understood that embodiments of the present disclosure may be used in conjunction with a 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 obtained 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 the specifically described materials may be used. Although many of the examples provided herein describe the various layers as comprising a single material, it should be understood that a combination of materials may be used, such as a mixture of a host and a dopant, or more generally, a mixture. In addition, the layers may have various sub-layers. 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, the 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, for example, Figure 1 and 2 Multiple layers of said different organic materials.

[0019] Structures and materials not specifically described may also be used, such as OLEDs containing 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 another example, an OLED having a single organic layer may be used. OLEDs may be stacked, such as described in U.S. Pat. No. 5,707,745 to Forrest et al., which is incorporated by reference in its entirety. OLED structures may deviate from Figure 1 and 2 For example, the substrate may include angled reflective surfaces 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 entirety.

[0020] Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation, inkjet (as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, incorporated by reference in their entirety), organic vapor phase deposition (OVPD) (as described in U.S. Pat. No. 6,337,102 to Forrest et al., incorporated by reference in their entirety), and deposition by organic vapor jet printing (OVJP) (as described in U.S. Pat. No. 7,431,968, incorporated by reference in their 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 other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding (as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entirety), and patterning associated with some of the deposition methods such as inkjet and organic vapor jet printing (OVJP). Other methods may also be used. The material to be deposited may be modified to make it compatible with a specific deposition method. For example, branched or unbranched substituents such as alkyl and aryl groups, preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to withstand solution processing. Substituents having 20 or more carbons may be used, and 3 to 20 carbons are a preferred range. Materials having asymmetric structures may have better solution processability than materials having symmetric structures because asymmetric materials may have a lower tendency to recrystallize. Dendritic polymer substituents may be used to enhance the ability of small molecules to withstand solution processing.

[0021] Unless otherwise specified, the following terms used herein are defined as follows:

[0022] As used herein, the term "organic" includes polymeric materials and small molecule organic materials that can be used to make organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and a "small molecule" may actually be quite large. In some cases, a small molecule may include a repeating unit. For example, the use of a long chain alkyl group as a substituent does not remove a molecule from the "small molecule" category. Small molecules can also be incorporated into polymers, for example as a side group on a polymer backbone or as part of a backbone. Small molecules can also serve as the core portion of a dendritic polymer, which consists of a series of chemical shells built on the core portion. The core portion of a dendritic polymer can be a fluorescent or phosphorescent small molecule emitter. A dendritic polymer can be a "small molecule", and it is believed that all dendritic polymers currently used in the field of OLEDs are small molecules.

[0023] As used herein, "top" means farthest from the substrate, while "bottom" means closest to the substrate. When a first layer is described as being "disposed above" a second layer, the first layer is disposed farther from the substrate. Unless it is specified that the first layer is "in contact with" the second layer, there may be other layers between the first and second layers. For example, a cathode may be described as being "disposed on" an anode even though various organic layers are present between the cathode and the anode.

[0024] As used herein, "solution processable" means capable of being dissolved, dispersed or transported in and / or deposited from a liquid medium, either in solution or suspension form.

[0025] When a ligand is believed to directly contribute to the photosensitive property of an emissive material, the ligand may be referred to as "photosensitive." A ligand may be referred to as "ancillary" when the ligand is not believed to contribute to the photosensitive property of an emissive material, but the ancillary ligand may alter the properties of the photosensitive ligand.

[0026] As used herein, and as will be generally understood by one skilled in the art, a first "highest occupied molecular orbital" (HOMO) or "lowest unoccupied molecular orbital" (LUMO) energy level is "greater than" or "higher than" a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Since the ionization potential (IP) is measured as a negative energy relative to the vacuum energy level, a higher HOMO energy level corresponds to an IP with a smaller absolute value (less negative IP). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) with a smaller absolute value (less negative EA). On a conventional energy level diagram with the vacuum energy level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A "higher" HOMO or LUMO energy level appears to be closer to the top of this diagram than a "lower" HOMO or LUMO energy level.

[0027] As used herein, and as one skilled in the art would generally understand, a first work function is "greater than" or "higher than" a second work function if the first work function has a higher absolute value. Because work functions are typically measured as negative numbers relative to the vacuum level, this means that a "higher" work function is more negative. On a conventional energy level diagram with the vacuum level at the top, a "higher" work function is illustrated as being farther away from the vacuum level in a downward direction. Thus, the definition of HOMO and LUMO energy levels follows different rules than work functions.

[0028] The terms "halo," "halogen," and "halo" are used interchangeably and refer to fluorine, chlorine, bromine, and iodine.

[0029] The term "acyl" refers to a substituted carbonyl (C(O)-R s ).

[0030] The term "ester" refers to a substituted oxycarbonyl (-OC(O)-R s OR-C(O)-OR s ) group.

[0031] The term "ether" refers to -OR s Group.

[0032] The terms "thio" or "thioether" are used interchangeably and refer to -SR s Group.

[0033] The term "sulfinyl" refers to -S(O)-R s Group.

[0034] The term "sulfonyl" refers to -SO2-R s Group.

[0035] The term "phosphino" refers to -P(R s )3 groups, wherein each R s Can be the same or different.

[0036] The term "silyl" refers to -Si(R s )3 groups, wherein each R s Can be the same or different.

[0037] The term "boryl" refers to -B(R s )2 group or its Lewis adduct -B(R s )3 groups, wherein R s Can be the same or different.

[0038] In each of the above, R s It may be hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, and combinations thereof. s Selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof.

[0039] The term "alkyl" refers to and includes straight and branched chain alkyl groups. Preferred alkyl groups are those containing one to fifteen carbon atoms and include 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, etc. In addition, the alkyl group may be optionally substituted.

[0040] The term "cycloalkyl" refers to and includes monocyclic, polycyclic and spiroalkyl groups. Preferred cycloalkyl groups are cycloalkyl groups containing 3 to 12 ring carbon atoms, and include cyclopropyl, cyclopentyl, cyclohexyl, bicyclo[3.1.1]heptyl, spiro[4.5]decyl, spiro[5.5]undecyl, adamantyl, etc. In addition, the cycloalkyl group may be optionally substituted.

[0041] The term "heteroalkyl" or "heterocycloalkyl" refers to an alkyl or cycloalkyl group, 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. In addition, the heteroalkyl or heterocycloalkyl group may be optionally substituted.

[0042] The term "alkenyl" refers to and includes straight and branched alkenyl groups. 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. As used herein, the term "heteroalkenyl" refers to an alkenyl group in which at least one carbon atom is 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. In addition, alkenyl, cycloalkenyl or heteroalkenyl groups may be optionally substituted.

[0043] The term "alkynyl" refers to and includes straight and branched chain alkynyl groups. Alkynyl groups are generally alkyl groups that include at least one carbon-carbon triple bond in the alkyl chain. Preferred alkynyl groups are alkynyl groups containing two to fifteen carbon atoms. In addition, alkynyl groups may be optionally substituted.

[0044] The terms "aralkyl" or "arylalkyl" are used interchangeably and refer to an alkyl group substituted with an aryl group. Additionally, the aralkyl group may be optionally substituted.

[0045] The term "heterocyclic group" refers to and includes aromatic and non-aromatic cyclic groups 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. Aromatic heterocyclic groups can be used interchangeably with heteroaryl. Preferred non-aromatic heterocyclic groups are heterocyclic groups containing 3 to 7 ring atoms including at least one heteroatom, and include cyclic amines, such as morpholinyl, piperidinyl, pyrrolidinyl, etc., and cyclic ethers / thioethers, such as tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, etc. In addition, heterocyclic groups can be optionally substituted.

[0046] The term "aryl" refers to and includes monocyclic aromatic hydrocarbon groups and polycyclic aromatic ring systems. Polycyclic rings may have two or more rings in which two carbons are common to two adjacent rings (the rings are "fused"), wherein at least one of the rings is an aromatic hydrocarbon group, for example, the other rings may be cycloalkyl, cycloalkenyl, aryl, heterocyclic and / or heteroaryl. Preferred aryl groups are those containing six to thirty carbon atoms, preferably six to twenty carbon atoms, and more preferably six to twelve carbon atoms. Particularly preferred are aryl groups having six carbons, ten carbons or twelve carbons. Suitable aryl groups include phenyl, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, Perylene and azulene, preferably phenyl, biphenyl, terphenyl, triphenylene, fluorene and naphthalene. In addition, the aryl group may be optionally substituted.

[0047] The term "heteroaryl" refers to and includes monocyclic aromatic groups and polycyclic aromatic ring systems that include at least one heteroatom. Heteroatoms include, but are not limited to, O, S, N, P, B, Si and Se. In many cases, O, S or N are preferred heteroatoms. Monocyclic heteroaromatic systems are preferably monocyclic rings with 5 or 6 ring atoms, and the rings may have one to six heteroatoms. Heteropolycyclic ring systems may have two or more rings in which two atoms are common to two adjacent rings (the rings are "fused"), wherein at least one of the rings is a heteroaryl, for example, the other rings may be cycloalkyl, cycloalkenyl, aryl, heterocycle and / or heteroaryl. Heteropolycyclic aromatic ring systems may have one to six heteroatoms on each ring of the polycyclic aromatic ring system. Preferred heteroaryls are heteroaryls containing three to thirty carbon atoms, preferably three to twenty carbon atoms, and more preferably three to twelve carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridyl indole, 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, quinazole In some embodiments, the heteroaryl group is substituted with 1,2-azaborane, 1,3-azaborane, 1,4-azaborane, borazine and aza analogs thereof. In some embodiments, the heteroaryl group is substituted with 1,2-azaborane, 1,3-azaborane, 1,4-azaborane, borazine and aza analogs thereof. In some embodiments, the heteroaryl group is substituted with 1,2-azaborane, 1,3-azaborane, 1,4-azaborane, borazine and aza analogs thereof. In some embodiments, the heteroaryl group is substituted with 1,2-azaborane, 1,3-azaborane, 1,4-azaborane, borazine and aza analogs thereof. In some embodiments, the heteroaryl group is substituted with 1,2-azaborane, 1,3-azaborane, 1,4-azaborane, borazine and aza analogs thereof.

[0048] Among the aryl and heteroaryl groups listed above, triphenylene, naphthalene, anthracene, dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, pyrazine, pyrimidine, triazine and benzimidazole and their respective corresponding aza analogs are of particular interest.

[0049] As used herein, the terms alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aralkyl, heterocyclyl, aryl and heteroaryl are independently unsubstituted or substituted with one or more typical substituents.

[0050] In many cases, the general substituent is selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, boryl, and combinations thereof.

[0051] In some cases, preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, thio, boryl, and combinations thereof.

[0052] In some cases, more preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silanyl, boryl, aryl, heteroaryl, thio, and combinations thereof.

[0053] In other cases, the most preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof.

[0054] The terms "substituted" and "substituted" refer to the bonding of substituents other than H to the relevant positions, such as carbon or nitrogen. For example, when R 1 When it represents a single substitution, one R 1 must not be H (i.e., substituted). Similarly, when R 1 When it indicates disubstituted, the two R 1 must not be H. Similarly, when R 1 When it indicates zero substitution or no substitution, R 1 For example, it can be hydrogen with available valences for the ring atoms, such as the carbon atoms of benzene and the nitrogen atoms in pyrrole, or simply none for ring atoms with fully saturated valences, such as the nitrogen atoms in pyridine. The maximum number of substitutions possible in the ring structure will depend on the total number of available valences in the ring atoms.

[0055] As used herein, "combinations thereof" means that one or more members of the applicable list are combined to form a known or chemically stable arrangement that a person of ordinary skill in the art can envision from the applicable list. For example, alkyl and deuterium can be combined to form partially or fully deuterated alkyl; halogen and alkyl can be combined to form haloalkyl substituents; and halogen, alkyl and aryl can be combined to form haloaralkyl. In one example, the term substitution includes a combination of two to four listed groups. In another example, the term substitution includes a combination of two to three groups. In yet another example, the term substitution includes a combination of two groups. Preferred combinations of substituents are combinations containing up to fifty atoms that are not hydrogen or deuterium, or combinations including up to forty atoms that are not hydrogen or deuterium, or combinations including up to thirty atoms that are not hydrogen or deuterium. In many cases, preferred combinations of substituents will include up to twenty atoms that are not hydrogen or deuterium.

[0056] 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 corresponding aromatic ring can be replaced by a nitrogen atom, for example and without any limitation, azatriphenylene encompasses dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. Other nitrogen analogs of the aza-derivatives described above can be readily envisioned by one of ordinary skill in the art, and all such analogs are intended to be encompassed by the term as set forth herein.

[0057] As used herein, "deuterium" refers to an isotope of hydrogen. Deuterated compounds can be easily prepared using methods known in the art. For example, U.S. Patent No. 8,557,400, Patent Publication No. WO 2006 / 095951 and U.S. Patent Application Publication No. US 2011 / 0037057 (which are incorporated herein by reference in their entirety) describe the preparation 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. (Review) 2007, 46, 7744-65 (which are incorporated by reference in their entirety) respectively describe the deuteration of methylene hydrogen in benzylamine and the effective way to replace aromatic ring hydrogen with deuterium.

[0058] It should be understood that when a molecular fragment is described as a substituent or otherwise attached to another part, its name can be written as if it is a fragment (e.g., phenyl, phenylene, naphthyl, dibenzofuranyl) or as if it is a whole molecule (e.g., benzene, naphthalene, dibenzofuran). As used herein, these different ways of naming substituents or attaching fragments are considered equivalent.

[0059] In some cases, a pair of adjacent substituents may be optionally joined or fused to form a ring. Preferred rings are five, six or seven membered carbocyclic or heterocyclic rings, including two cases where the portion of the ring formed by the substituent pair is saturated and the portion of the ring formed by the substituent pair is unsaturated. As used herein, "adjacent" means that the two substituents involved may be immediately adjacent to each other on the same ring, or on two adjacent rings with two closest available substitutable positions (such as the 2, 2' positions in biphenyl or the 1, 8 positions in naphthalene), as long as they can form a stable fused ring system.

[0060] OLED of the present disclosure

[0061] It is known that the emission spectrum of the excitation complex is relatively broad. However, for many OLED applications, it is required that the OLED device has a narrow emission spectrum. For example, in order for the blue light microcavity to present the most saturated color and the highest efficiency, the OLED requires a narrow spectrum emitter. In addition, the stabilization (i.e., longer lifetime) of the OLED device can be achieved by using materials with lower LUMO energy levels in the device. Therefore, the formation of excitation complexes in OLEDs is generally something that needs to be avoided. However, in many cases, an excitation complex can be formed between the shallowest (i.e., highest) HOMO energy level material and the deepest (i.e., lowest) LUMO energy level material in the OLED emission layer. The total emission of the OLED device may therefore be contaminated by the emission from the excitation complex. In some cases, the emission may be a mixture of the emission of the excitation complex and the emission of the emitter, and in other cases, the emission may be completely dominated by the excitation complex.

[0062] An OLED configuration is disclosed that, despite containing an exciplex whose emission spectrum is redder than that of the emitter, the emission from the exciplex is suppressed so that the overall OLED emission spectrum is still dominated by the emission of the emitter. This is achieved by a number of different approaches. One embodiment is to design the emitter so that the exciplex formation between the host material and the emitter is not part of the emission spectrum of the OLED, despite the energy of the exciplex as indicated by the HOMO and LUMO energy levels being lower than the triplet energy T1 of the emitter.

[0063] Prior to the present disclosure, it was not known that the contribution of an exciplex to the emission of an OLED could be suppressed even when the exciplex is in the lowest energy state in the OLED.

[0064] To help mathematically determine the difference between when exciplex formation occurs and when it does not, we utilize the root mean square (RMSD) function shown below, Equation (1). This function returns a single value that is the average difference between the two spectra at all wavelengths.

[0065]

[0066] In equation (1), n ​​is the total number of points and I1 and I2 are the normalized intensity spectra (electroluminescence (EL) or photoluminescence (PL)) as a function of wavelength λ. Importantly, the spectra being compared are shifted to the same peak wavelength and normalized, which eliminates some spectral differences that can arise from placing the materials into materials of different dielectric constants. Functions I1 and I2 must have exactly the same number of points, which can be achieved by interpolating the existing data to a fixed number of wavelengths, and must cover the same wavelength range, also achieved by interpolation. To demonstrate the versatility of this function, we first plot the measured photoluminescence intensity (PL) of emitter 1 and emitter 2 doped at 12 vol% in host compounds 5 and 3, where both spectra are normalized to a value of one and shifted to a peak at a wavelength of 468 nm. This curve is plotted at Figure 3 . Based on the energy levels of compound 5, the probability of forming an exciplex with either emitter is zero. The PL spectra of each emitter in compound 5 represent a reference that can be compared for cases where the energetics of the molecule predict the formation of an exciplex. When emitters 1 and 2 are doped into compound 3, the energy levels of the material can predict what will happen. For the two emitters in compound 3, the emitter has the highest HOMO and compound 3 has the lowest LUMO. We can then calculate the energy difference (ΔE) of the exciplex that will occur based on the highest energy HOMO and the lowest energy LUMO for each case: ΔE Emitter1 =|-5.33--2.78|=2.55eV and ΔE Emitter2 =|-5.35--2.78|=2.57 eV for these emitters doped into compound 3. For emitter 1 and emitter 2, ΔE is less than the triplet energy E of 2.73 and 2.81 eV, respectively. T , indicating that an exciplex should be formed between each emitter and compound 3. In fact, for emitter 2 in compound 3 and Figure 3 As can be seen in the figure, additional broad and red-shifted emission is observed. We attribute the distortion of the PL spectrum of emitter 2 in compound 3 to indicate the formation of an exciplex between the two materials. In contrast, when emitter 2 is doped into compound 5, its spectrum changes very little, although it also meets the energy criteria for exciplex formation, i.e., the triplet energy of the phosphorescent emitter is greater than the energy of the exciplex, ΔE, which can be expressed mathematically as E T -ΔE Emitter2 >0.

[0067] As a stepping stone to calculating a single number representing the difference in PL spectra between 2 different films and providing a quantitative method for determining exciplex formation, we plotted the difference as a function of wavelength for the PL spectra of emitter 1 and emitter 2 in host compounds 3 and 5, respectively. For each emitter, Figure 4 The absolute values ​​of the differences between the normalized and shifted spectra of the emitters in compound 3 and compound 5 are plotted in FIG.

[0068] Figure 4 The curves in show that emitter 1 and emitter 2 behave differently when doped into host compounds 3 and 5. Emitter 1 exhibits minimal differences when doped into both host compounds. However, at many wavelengths, emitter 2 exhibits significant differences in the PL spectra of compound 5 compared to compound 3. Importantly, the maximum difference values ​​occur in the wavelength range of about 500 nm to >650 nm, which is the same region in the PL spectrum of emitter 2 in compound 3 that is altered compared to the PL in compound 5 ( Figure 3 ). The sharp features from about 430 nm to about 480 nm in both emitters arise from the fact that the shape of the PL intensity around the maximum is slightly different, resulting in a large difference. This difference is expected to be because each material has a different dielectric constant, resulting in slight differences in the measured PL spectra around regions of high electrical slope, or may arise from differences in the original sampling of the data and then interpolated around those high slope regions.

[0069] Given that Figure 4 , we can now calculate the RMSD values ​​for each spectrum. We find that the RMSD for emitter 1 (from comparing the PL spectra of emitter 1 doped at 12 vol. % into host compounds 3 and 5) is 0.021, while the RMSD for emitter 2 (from comparing the PL spectra of emitter 2 doped at 12 vol. % into host compounds 3 and 5) is 0.198. For host and emitter combinations that produce exciplexes, the RMSD function is almost 10× (based on Figure 3 ), thus demonstrating the validity of using RMSD to determine whether a material combination produces an exciplex and the quantitative number of exciplexes produced.

[0070] Subsequently, a baseline RMSD level that occurs when comparing different spectra is determined.First, the RMSD values ​​for the different types of spectral measurements are calculated. Figure 5Curves showing the normalized and shifted PL spectra of emitter 1 (12 vol%) in host compound 5 and the EL spectrum of emitter 1 in the host, which is a mixture of compound 5 and compound 4 (60 vol% compound 4 and 12 vol% emitter 1). The RMSD is 0.012, which is quite low. The RMSD in the EL is also calculated, where the emission layer (EML) composition is compound 5 doped with 40 vol% compound 3 and 10 or 15 vol% emitter 1. The RMSD is 0.0073. The RMSD in the EL is also calculated, where the EML composition is compound 5 doped with 20 vol% compound 3 and 15 vol% emitter 1 to compound 5 doped with 60 vol% compound 3 and 15 vol% emitter 1. The RMSD is 0.0147. Given the RMSD of comparing spectra (EL relative to PL) produced by different methods of generating spectra, changing the percentage of emitter doping, and changing the ratio of the host in the EML are all lower values, indicating that RMSD is a robust method for comparing spectra. We further reviewed many different spectra where the expected exciplex was not present and found that RMSD differences greater than 0.05 were meaningful and a good value to consider exciplex formation significant.

[0071] Sometimes, it is useful to convert a purely mathematical expression into a textual description. RMSD can be recast as a similar description. For example, if the 2 spectra being compared are identical, then the RMSD is 0. The two spectra are completely similar or 100% similar. Therefore, the similarity between two spectra can be defined and quantified as a percentage using the following relationship: (1-RMSD)*100. Therefore, in this context, all spectra that are ≥95% similar will be considered identical due to the fact that RDMS values ​​less than 0.05 will not differ meaningfully.

[0072] Table 1 below lists the HOMO, LUMO, triplet energy T1 and predicted exciton energy levels of compounds 1 to 5, as well as emitters 1 and 2. For emitters 1 and 2, compounds 1, 2 and 3 should form exciton complexes based on the energy level, while compounds 4 and 5 should not. The HOMO energy was estimated from the first oxidation potential derived from cyclic voltammetry. The LUMO energy was estimated from the first reduction potential derived from cyclic voltammetry. The triplet energy T1 of the emitter compound was measured using the peak wavelength from the photoluminescence at 77K. In selecting the emitter-host combination, if the condition a≤E is satisfied T -ΔE≤b, an excited complex should be formed. T -ΔE≤b, E Tis the triplet energy T1 of the emitter, which is the lowest T1 energy among all materials in the organic emission layer, ΔE is the energy gap between the HOMO energy of the material with the highest HOMO energy in the organic emission layer and the LUMO energy of the material with the lowest LUMO energy in the organic emission layer, a has a value of 0.00 to 0.15 eV, and b has a value of 0.05 to 0.45 eV. Although the above conditions are met by designing a suitable emitter, the OLED will have an emission spectrum that is at least 95% similar to the emission spectrum of an OLED whose organic emission layer consists of an emitter and an inert host.

[0073] Figure 6 EL spectra of emitter 1 doped in four different mixtures of compound 5 and compounds 1, 2, 3 and 4 are shown in FIG. For each host compound 1-4, a mixture was prepared according to the following recipes: compound 5 doped with 40 vol% compound 1 and 12 vol% emitter 1; compound 5 doped with 40 vol% compound 2 and 12 vol% emitter 1; compound 5 doped with 40 vol% compound 3 and 12 vol% emitter 1; compound 5 doped with 40 vol% compound 4 and 12 vol% emitter 1. We found that the RMSDs of the mixtures with compound 5 and 1, 2 or 3 were 0.0201, 0.0306 and 0.0239, respectively, compared to compound 5 doped with compound 4 (where exciplex formation was not predicted energetically). Or in simple language, the EMLs with the same composition but changing the host from compound 4 to compound 1, 2 or 3 are all within 3% of each other and are therefore equally effective. Therefore, there is no exciton formation between the emitter 1 and these hosts, although the energetics of the HOMO energy level of the emitter and the LUMO energy level of the host predict that there should be exciton formation. This result is completely unexpected. Without being bound by any theory, this unexpected result can be attributed to the steric effect from the emitter. The energy of the exciton has a spatial component and increases as the distance between the hole and electron parts of the wave function increases. If the spatial component of the emitter increases the distance of the excited complex between the emitter and the E-type host, it will produce a higher excited complex energy and push the energy of the excited complex to be greater than the triplet energy T1 of the emitter. Therefore, emitter molecules with greater steric protection enable the use of E-type hosts with lower LUMO energy levels, which in turn leads to stabilization of the overall device. The advantage of expanding the range of energy levels that can be used for the device is particularly beneficial to blue light emitters. Therefore, the OLED configuration disclosed herein provides a signpost for designing emitter molecules and selecting appropriate host systems, especially e-hosts, to obtain stable OLEDs, especially stable blue light phosphorescent OLEDs.

[0074] Table 1: Energy levels of emitter and host compounds and energy-level-based predictions of exciton formation.

[0075]

[0076] In Table 1, the ΔE of each EML mixture is calculated by first determining which compound in the mixture has a high HOMO energy (the highest HOMO energy of all materials in the EML mixture) and which compound in the mixture has a low LUMO energy (the lowest LUMO energy of all materials in the EML mixture). ΔE is then the energy gap between the high HOMO energy and the low LUMO energy. Next, E is determined. T -ΔE and whether the following conditions are satisfied: a≤E T -ΔE≤b, where E T is the triplet energy T1 of the first emitter, which is the lowest T1 energy among all materials in the organic emission layer, and wherein a is 0.00 to 0.15 eV, and b is 0.05 to 0.45 eV.

[0077] The compounds referenced in the data shown in Table 1 are shown below:

[0078]

[0079] Solution cyclic voltammetry and differential pulse voltammetry were performed using a CH Instruments Model 6201B potentiostat with anhydrous dimethylformamide solvent and tetrabutylammonium hexafluorophosphate as supporting electrolyte. Glassy carbon and platinum and silver wires were used as working, counter, and reference electrodes, respectively. The electrochemical potential was referenced to an internal ferrocene-ferrocene redox couple (Fc + / Fc). HOMO =-[(E ox1 :Fc + / Fc)+4.8], and E LUMO =-[(E red1 :Fc + / Fc)+4.8], where E ox1 is the first oxidation potential, and E red1 is the first reduction potential.

[0080] An organic light-emitting device (OLED) is disclosed herein, comprising an anode, a cathode, and an organic emission layer disposed between the anode and the cathode. The organic emission layer comprises a first host material having a highest occupied molecular orbital (HOMO) energy and a lowest unoccupied molecular orbital (LUMO) energy, and an emitter material having a HOMO energy and a LUMO energy. The emitter is selected from the group consisting of: a phosphorescent metal complex and a delayed fluorescent emitter. The emitter and the host material in the organic emission layer satisfy the following conditions: a≤E T -ΔE≤b; where E Tis the triplet energy T1 of the emitter, which is the lowest T1 energy among all materials in the organic emission layer; ΔE is the energy gap between the high HOMO energy and the low LUMO energy; wherein a is 0.00 to 0.15 eV, and b is 0.05 to 0.45 eV; and wherein the emission spectrum of the OLED is at least 95% similar to the emission spectrum of an OLED whose organic emission layer consists of the first emitter and the inert host. "High HOMO energy" is defined as the highest HOMO energy among all materials in the organic emission layer, and "low LUMO energy" is defined as the lowest LUMO energy among all materials in the organic emission layer.

[0081] In some embodiments, all materials in the organic emission layer may be in a mixture. The mixture may be a homogeneous mixture or the components of the organic emission layer may be in graded concentrations through the thickness of the emission layer. The concentration grading may be linear, nonlinear, sinusoidal, etc.

[0082] The emitter can be a phosphorescent metal complex or a delayed fluorescent emitter.

[0083] In some embodiments of OLED, a is 0.15 eV. In some embodiments, a is 0.10 eV. In some embodiments, a is preferably 0.05 eV. In some embodiments, b is 0.05 eV. In some embodiments, b is 0.15 eV. In some embodiments, b is 0.25 eV. In some embodiments, b is preferably 0.35 eV. In some embodiments, E T is at least 2.60 eV. In some embodiments, E T is at least 2.65 eV. In some embodiments, E T is at least 2.70 eV. In some embodiments, E T Preferably it is at least 2.75 eV.

[0084] In some embodiments of OLEDs, the high HOMO energy is the HOMO energy of the emitter and the low LUMO energy is the LUMO energy of the first host. In some embodiments, the high HOMO energy is the HOMO energy of the first host and the low LUMO energy is the LUMO energy of the emitter.

[0085] In some embodiments, the OLED further comprises a second host, wherein the high HOMO energy is the HOMO energy of the first host, and the low LUMO energy is the LUMO energy of the second host. In some embodiments, the high HOMO energy is the HOMO energy of the second host, and the low LUMO energy is the LUMO energy of the first host.

[0086] In some embodiments of OLEDs comprising a second host, the first host, the second host, and the emitter are the only components in the emissive layer. In some embodiments, the first host, the second host, and the emitter are the only components in the emissive layer.

[0087] In some embodiments, the OLED is subjected to 10 mA / cm 2 The operating voltage at is less than 6.0 V. In some embodiments, the OLED is 2 The operating voltage at is less than 5.0 V. In some embodiments, the OLED is 2 The operating voltage at is less than 4.0V.

[0088] In some embodiments of OLEDs, the first host comprises at least one chemical moiety selected from the group consisting of triphenylene, carbazole, indolocarbazole, benzothiophene, benzofuran, dibenzothiophene, dibenzofuran, pyridine, pyridazine, pyrimidine, pyrazine, triazine, imidazole, boryl, 5,9-dioxa-13b-boranenaphtho[3,2,1-de]anthracene, and aza variants thereof.

[0089] In some embodiments of OLEDs, the emitter is a phosphorescent blue emitter. A blue emitter is a phosphorescent emitter having an emission λmax of less than 490 nm, less than 480 nm, less than 470 nm, or preferably less than 460 nm, or an emission in CIE coordinates of: X<0.3, <0.25, <0.2, or preferably <0.18, and Y<0.5, <0.4, <0.3, or preferably <0.2.

[0090] In some embodiments of OLEDs, the emitter has the formula M(L 1 ) x (L 2 ) y (L 3 ) z ; where L 1 , L 2 and L 3 can be the same or different; x is 1, 2 or 3; y is 0, 1 or 2; z is 0, 1 or 2; x+y+z is the oxidation state of metal M; L 1 , L 2 and L 3 Each independently selected from the group consisting of:

[0091] Each X 1 To X 17are independently selected from the group consisting of carbon and nitrogen; X is selected from the group consisting of: BR', NR', PR', O, S, Se, C=O, S=O, SO2, CR'R", SiR'R" and GeR'R"; R' and R" are optionally fused or joined to form a ring; each R a , R b , R c and R d It can represent a single substitution to the maximum possible number of substitutions or no substitution; R', R", R a , R b , R c and R d are each independently hydrogen or a substituent selected from the group consisting of general substituents defined herein; and any two R a , R b , R c and R d Optionally fused or joined to form a ring or to form a multidentate ligand.

[0092] In some embodiments, R a , R b , R c and R d At least one of the R comprises a chemical group containing at least three 6-membered aromatic rings that are not fused to each other in close proximity. a , R b , R c and R d At least one of the R comprises a chemical group containing at least four 6-membered aromatic rings that are not fused to each other in close proximity. a , R b , R c and R d At least one of the R comprises a chemical group containing at least five 6-membered aromatic rings that are not fused to each other in close proximity. a , R b , R c and R d At least one of the R comprises a chemical group containing at least six 6-membered aromatic rings that are not fused to each other in close proximity. a , R b , R c and R d At least one of the R comprises a chemical group containing terphenyl (more preferably m-terphenyl) or N-phenylcarbazole. In some embodiments, R a Contains chemical groups as described herein. A more detailed description of adding bulky groups to the ligand edge of an emitter complex has been disclosed in detail elsewhere, such as in US Application No. 16 / 807,877, the entire contents of which are incorporated herein by reference.

[0093] In some embodiments of OLEDs, where the emitter has the formula M(L 1 ) x (L 2 ) y (L 3 ) z , the emitter may have a formula selected from the group consisting of: Ir(L 1 )(L 2 )(L 3 )、Ir(L 1 )2(L 2 ) and Ir(L 1 )3, where L 1 , L 2 and L 3 are distinct and each independently selected from the group consisting of:

[0094]

[0095]

[0096] In some embodiments of the compounds, wherein the emitter has the formula M(L 1 ) x (L 2 ) y (L 3 ) z , the emitter may have the formula Pt(L 1 )2 or Pt(L 1 )(L 2 ) and L 1 and L 2 Each is a different bidentate ligand. In some embodiments, L 1 With another L 1 or L 2 In some embodiments, the emitter has the formula M(L 1 )2 or M(L 1 )(L 2 ), wherein M is Ir, Rh, Re, Ru or Os, and L 1 and L 2 Each is a different tridentate ligand. In some embodiments, L 1 Select from the group consisting of:

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] In some embodiments of OLEDs, where the emitter has the formula Pt(L 1 )2 or Pt(L 1 )(L 2 ), the emitter is selected from the following group 1 consisting of:

[0105] Each R A To R F It can represent a single substitution to the maximum possible number of substitutions or no substitution; R A To R F are each independently hydrogen or a substituent selected from the group consisting of general substituents defined herein; and any two R A To R F Optionally fused or joined to form a ring or to form a multidentate ligand. In some embodiments, R A To R F At least one of the comprises a chemical group comprising at least three 6-membered aromatic rings that are not fused immediately adjacent to each other.

[0106] In some embodiments of OLEDs, where the emitter has the formula Pt(L 1 )2 or Pt(L 1 )(L 2 ) and the emitter is selected from Group 1, R A Contains a chemical group containing at least three 6-membered aromatic rings that are not fused immediately adjacent to each other.

[0107] In some embodiments of OLEDs, the emitter is an E-type delayed fluorescent emitter.

[0108] In some embodiments, the emitter has the formula DLA; and wherein D is an electron donor group, A is an electron acceptor group, and L is a direct bond or a linking group. In some embodiments, the electron donor group comprises at least one chemical moiety selected from the group consisting of amino, indole, carbazole, indolocarbazole, benzothiophene, benzofuran, dibenzothiophene, dibenzofuran, and combinations thereof. In some embodiments, the electron acceptor group comprises at least one chemical moiety selected from the group consisting of pyridine, pyridazine, pyrimidine, pyrazine, triazine, nitrile, isonitrile, and boryl.

[0109] According to another aspect, a consumer product comprising the inventive OLED disclosed herein is also disclosed. The consumer product may be one of the following: a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a lamp for interior or exterior lighting and / or signaling, a head-up display, a fully transparent or partially transparent display, a flexible display, a laser printer, a telephone, a cellular telephone, a tablet computer, a tablet phone, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay (a display with a diagonal of less than 2 inches), a 3D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, a light therapy device, and a sign.

[0110] In general, any metal complex or organic compound can be used as a host material in the OLED of the present disclosure, as long as the energy requirements described above are met in the EML. For example, it can be an electron transport host (e-host) accompanied by a hole transport emitter, or vice versa. Such a family of e-hosts is disclosed in U.S. Patent Application No. 16 / 683,507 filed on November 14, 2019, the contents of which are incorporated herein by reference.

[0111] The host compound of the OLED of the present disclosure may be a metal complex. Examples of metal complexes used as hosts preferably have the following general formula:

[0112]

[0113] Where Met is a metal; (Y 103 -Y 104 ) is a bidentate ligand, Y 103 and Y 104 is independently selected from C, N, O, P and S; L 101 is another ligand; k' is an integer value from 1 to the maximum number of ligands that can be attached to the metal; and k'+k" is the maximum number of ligands that can be attached to the metal.

[0114] In one aspect, the metal complex is:

[0115]

[0116] where (ON) is a bidentate ligand with a metal coordinated to O and N atoms.

[0117] In another aspect, Met is selected from Ir and Pt. In another aspect, (Y 103 -Y 104 ) is a carbene ligand.

[0118] In one aspect, the host compound contains at least one selected from the following group: a group consisting of aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, Perylene and azulene; a 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, naphthridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuranopyridine, furanodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine and selenophenodipyridine; and a group consisting of 2 to 10 cyclic structural units, which are groups of the same type or different types selected from aromatic hydrocarbon ring groups and aromatic heterocyclic groups and are directly or via at least one of oxygen atoms, nitrogen atoms, sulfur atoms, silicon atoms, phosphorus atoms, boron atoms, chain structural units and aliphatic ring groups. Each option in each group may be unsubstituted or substituted with a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and combinations thereof.

[0119] In one aspect, the subject compound contains at least one of the following groups in the molecule:

[0120]

[0121]

[0122] Where R 101 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino and combinations thereof, and when it is aryl or heteroaryl, it has a similar definition to Ar mentioned above. k is an integer from 0 to 20 or from 1 to 20. X 101 To X 108 Z is independently selected from C (including CH) or N. 101 and Z 102Independently selected from NR 101 , O or S.

[0123] Non-limiting examples of host materials that can be used in OLEDs in combination with the materials disclosed herein are exemplified below, along with references disclosing those materials: EP2034538, EP2034538A, EP2757608, JP2007254297, KR20100079458, KR20120088644, KR20120129733, KR20130115564, TW201329200, US20030175553, US20050238919, US20060280965, US2009 0017330, US20090030202, US20090167162, US20090302743, US20090309488, US20100012931, US20100084966, US20100187984, US2010187984, US2012075273, US2012126221, US2013009543, US2013105787, US2013175519, US2014001446, US20140183503, U S20140225088, US2014034914, US7154114, WO2001039234, WO2004093207, WO2005014551, WO2005089025, WO2006072002, WO200 6114966, WO2007063754, WO2008056746, WO2009003898, WO2009021126, WO2009063833, WO2009066778, WO2009066779, WO20090 86028, WO2010056066, WO2010107244, WO2011081423, WO2011081431, WO2011086863, WO2012128298, WO2012133644, WO2012133 649. WO2013024872, WO2013035275, WO2013081315, WO2013191404, WO2014142472, US20170263869, US20160163995, US9466803,

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] In general, an OLED comprises at least one organic layer disposed between an anode and a cathode and electrically connected to the anode and the cathode. When an electric current is applied, the anode injects holes and the cathode injects electrons into the organic layer. The injected holes and electrons each migrate toward the oppositely charged electrode. When electrons and holes are confined to the same molecule, an "exciton" is formed, which is a localized electron-hole pair with an excited energy state. When the exciton relaxes through a light emission mechanism, light is emitted. In some cases, the exciton can be confined to an excimer or an excited complex. Non-radiative mechanisms (such as thermal relaxation) may also occur, but are generally considered undesirable.

[0130] Several OLED materials and configurations are described in US Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

[0131] The first OLEDs used emissive molecules that emitted light from a singlet state ("fluorescence"), as disclosed, for example, in US Pat. No. 4,769,292, which is incorporated by reference in its entirety. Fluorescence emission typically occurs in a time period of less than 10 nanoseconds.

[0132] Recently, OLEDs with emissive materials that emit light from triplet states ("phosphorescence") have been demonstrated. Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices", Nature, Vol. 395, 151-154, 1998 ("Baldo-I"); and Baldo et al., "Very high-efficiency green organic light-emitting devices based on electrophosphorescence", Appl. Phys. Lett., Vol. 75, No. 3, 4-6 (1999) ("Baldo-II"), which are incorporated by reference in their entirety. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704, Columns 5-6, which is incorporated by reference.

[0133] Figure 1 An organic light-emitting device 100 is shown. The figures are not necessarily drawn to scale. The 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 emission 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 blocking layer 170. The cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. The device 100 can be manufactured by depositing the described layers in sequence. The properties and functions of these different layers and example materials are described in more detail in US 7,279,704, columns 6-10, which is incorporated by reference.

[0134] More examples of each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated by reference in its entirety. Examples of emissive materials and host materials are disclosed in U.S. Patent 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. Patent Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entirety, disclose examples of cathodes including composite cathodes having a thin layer of metal (e.g., Mg:Ag) with an overlying transparent, conductive, sputter-deposited ITO layer. The theory and use of barrier layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are incorporated by reference in their entirety. 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 can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated by reference in its entirety.

[0135] Figure 2An inverted OLED 200 is shown. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole transport layer 225, and an anode 230. The device 200 can be manufactured by depositing the layers in order. Because the most common OLED configuration has a cathode disposed on the anode, and the device 200 has the cathode 215 disposed under the anode 230, the device 200 can be referred to as an "inverted" OLED. In the corresponding layers of the device 200, materials similar to those described with respect to the device 100 can be used. Figure 2 One example is provided of how some layers may be omitted from the structure of device 100 .

[0136] Figure 1 and 2 The simple layered structures described in are provided by way of non-limiting examples, and it should be understood that embodiments of the present disclosure may be used in conjunction with a 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 obtained by combining the various layers described in different ways, or the layers may be omitted entirely based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than the specifically described materials may be used. Although most of the examples provided herein describe the various layers as comprising a single material, it should be understood that a combination of materials (e.g., a mixture of a host and a dopant), or more generally, a mixture, may be used. In addition, 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, the 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, for example, Figure 1 and 2 Multiple layers of said different organic materials.

[0137] Structures and materials not specifically described may also be used, such as OLEDs containing 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 another example, an OLED having a single organic layer may be used. OLEDs may be stacked, such as described in U.S. Pat. No. 5,707,745 to Forrest et al., which is incorporated by reference in its entirety. OLED structures may deviate from Figure 1 and 2For example, the substrate may include an angled reflective surface to improve outcoupling, 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 Burwick et al., which are incorporated herein by reference in their entirety.

[0138] Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation, inkjet (as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, incorporated by reference in their entirety), organic vapor phase deposition (OVPD) (as described in U.S. Pat. No. 6,337,102 to Forrest et al., incorporated by reference in their entirety), and deposition by organic vapor jet printing (OVJP) (as described in U.S. Pat. No. 7,431,968, incorporated by reference in their entirety). Other suitable deposition methods include spin coating and other solution-based processes. Solution-based processes are preferably carried out in a nitrogen or inert atmosphere. For other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding (as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entirety), and patterning associated with some of the deposition methods such as inkjet and organic vapor jet printing (OVJP). Other methods may also be used. The material to be deposited may be modified to make it compatible with a specific deposition method. For example, branched or unbranched substituents (e.g., alkyl and aryl) preferably containing at least 3 carbons may be used in small molecules to promote their ability to undergo solution processing. Substituents having 20 or more carbons may be used, and 3 to 20 carbons are a preferred range. Materials having asymmetric structures may have better solution processability than materials having symmetric structures because asymmetric materials may have a lower tendency to recrystallize. Dendritic polymer substituents may be used to enhance the ability of small molecules to undergo solution processing.

[0139] The device manufactured according to the embodiment of the present disclosure may further optionally include a barrier layer. One purpose of the barrier layer is to protect the electrode and the organic layer from being damaged by exposure to harmful substances (including moisture, steam and / or gas, etc.) in the environment. The barrier layer can be deposited on the substrate, the electrode, deposited under the substrate, the electrode, or deposited next to the substrate, the electrode, or deposited on any other part of the device (including the edge). The barrier layer may include a single layer or multiple layers. The barrier layer can be formed by various known chemical vapor deposition techniques, and may include a composition having a single phase and a composition having multiple phases. Any suitable material or material combination can be used for the barrier layer. The barrier layer may be combined with an inorganic compound 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. Patent No. 7,968,146, PCT Patent Application No. PCT / US2007 / 023098 and No. PCT / US2009 / 042829, which are incorporated herein by reference in their entirety. In order to be considered a "mixture", the aforementioned polymeric material and non-polymeric material constituting the barrier layer should be deposited under the same reaction conditions and / or deposited simultaneously. The weight ratio of polymeric material to non-polymeric material can be in the range of 95:5 to 5:95. The polymeric material and non-polymeric material can be produced from the same precursor material. In one example, the mixture of polymeric material and non-polymeric material consists essentially of polymeric silicon and inorganic silicon.

[0140] It should be understood that the various embodiments described herein are only examples, and are not intended to limit the scope of the present invention. For example, many of the materials and structures described herein can be replaced with other materials and structures without departing from the spirit of the present invention. The present invention as required can therefore include variations of the specific examples and preferred embodiments described herein, as will be apparent to those skilled in the art. It should be understood that the various theories about why the present invention works are not intended to be restrictive.

Claims

1. An organic light-emitting device (OLED) having an emission spectrum, the OLED comprising: anode; cathode; and An organic emission layer disposed between the anode and the cathode, the organic emission layer comprising: a first host material having the highest occupied molecular orbital HOMO energy and the lowest unoccupied molecular orbital LUMO energy; and an emitter material having a HOMO energy and a LUMO energy; in, All materials in the organic emission layer are mixed together; The emitter material is selected from the group consisting of: phosphorescent metal complexes and delayed fluorescent emitters; The high HOMO energy is the highest HOMO energy among all materials in the organic emission layer; The low LUMO energy is the lowest LUMO energy among all materials in the organic emissive layer; a≤E T -ΔE≤b, where E T is the triplet energy T1 of the emitter material, which is the lowest T1 energy among all materials in the organic emission layer, ΔE is the energy gap between the high HOMO energy and the low LUMO energy, a is 0.00 to 0.15 eV, and b is 0.05 to 0.45 eV; wherein the emission spectrum of the OLED is at least 95% similar to the emission spectrum of an OLED whose organic emission layer consists of the emitter material and an inert host, wherein the inert host has an E T -ΔE<0; Wherein the emitter material has the formula M(L 1 ) x (L 2 ) y (L 3 ) z ; in, L 1 , L 2 and L 3 Can be the same or different; x is 1, 2, or 3; y is 0, 1, or 2; z is 0, 1, or 2; x+y+z is the oxidation state of metal M; L 1 , L 2 and L 3 Each independently selected from the group consisting of: in, Each X 1 To X 17 independently selected from the group consisting of carbon and nitrogen; X is selected from the group consisting of BR', NR', PR', O, S, Se, C=O, S=O, SO2, CR'R", SiR'R" and GeR'R"; R' and R" are optionally fused or joined to form a ring; Each R a , R b , R c and R d It can represent a single substitution to the maximum possible number of substitutions or no substitution; R', R", R a , R b , R c and R d are each independently hydrogen or a substituent selected from the group consisting of hydrogen, deuterium, halo, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, boryl, and combinations thereof; and Any two R a , R b , R c and R d Optionally fused or joined to form a ring or to form a multidentate ligand.

2. The OLED according to claim 1, wherein the emitter material is a phosphorescent metal complex.

3. The OLED of claim 1, wherein the emitter material is a delayed fluorescent emitter.

4. The OLED according to claim 1, wherein E T is at least 2.60 eV.

5. The OLED of claim 1, wherein the high HOMO energy is the HOMO energy of the emitter material and the low LUMO energy is the LUMO energy of the first host material.

6. The OLED of claim 1, wherein the high HOMO energy is the HOMO energy of the first host material and the low LUMO energy is the LUMO energy of the emitter material.

7. The OLED of claim 1, wherein the OLED further comprises a second host, wherein the high HOMO energy is the HOMO energy of the first host material and the low LUMO energy is the LUMO energy of the second host.

8. The OLED of claim 1, wherein the OLED further comprises a second host, wherein the high HOMO energy is the HOMO energy of the second host, and the low LUMO energy is the LUMO energy of the first host material.

9. The OLED of claim 1, wherein the device is subjected to a high current consumption at 10 mA / cm 2 The operating voltage is below 6.0V.

10. The OLED of claim 1, wherein the first host material comprises at least one chemical moiety selected from the group consisting of triphenylene, carbazole, indolocarbazole, benzothiophene, benzofuran, dibenzothiophene, dibenzofuran, pyridine, pyridazine, pyrimidine, pyrazine, triazine, imidazole, boryl, 5,9-dioxa-13b-borane naphtho[3,2,1-de]anthracene, and aza variants thereof.

11. The OLED of claim 1 , wherein the emitter material is a phosphorescent blue emitter.

12. The OLED according to claim 1, wherein R a , R b , R c and R d At least one of the comprises a chemical group comprising at least three 6-membered aromatic rings that are not fused immediately adjacent to each other.

13. The OLED of claim 1, wherein the emitter material has a formula selected from the group consisting of: Ir(L 1 )(L 2 )(L 3 )、Ir(L 1 )2(L 2 ) and Ir(L 1 )3; Where L 1 , L 2 and L 3 are different and each independently selected from the group consisting of:

14. The OLED of claim 1, wherein the emitter material has the formula M(L 1 )2 or M(L 1 )(L 2 ); Where M is Pt, and L 1 and L 2 are different bidentate ligands; or M is Ir, Rh, Re, Ru or Os, and L 1 and L 2 Each is a different tridentate ligand.

15. The OLED according to claim 1, wherein L 1 Select from the group consisting of:

16. The OLED of claim 14, wherein the emitter material is selected from the group consisting of: in, Each R A To R F It can represent a single substitution to the maximum possible number of substitutions or no substitution; R A To R F are each independently hydrogen or a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, boryl, and combinations thereof; and Any two R A To R F Optionally fused or joined to form a ring or to form a multidentate ligand.

17. The OLED according to claim 16, wherein R A To R F At least one of the comprises a chemical group comprising at least three 6-membered aromatic rings that are not fused immediately adjacent to each other.

18. A consumer product comprising the organic light emitting device (OLED) according to any one of claims 1 to 17.

19. The consumer product of claim 18, wherein the consumer product is selected from the group consisting of: a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a lamp for interior or exterior lighting and / or signaling, a head-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cellular telephone, a tablet computer, a tablet phone, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay having a diagonal of less than 2 inches, a 3D 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.

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