ORGANIC ELECTROLUMINESCENT MATERIAL AND DEVICE THEREOF

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to Chinese Patent Application No. 202210078763.2 filed on Jan. 25, 2022 and Chinese Patent Application No. 202211472133.X filed on Nov. 23, 2022, the disclosures of both applications being incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to compounds for organic electronic devices, for example, organic electroluminescent devices. More particularly, the present disclosure relates to a metal complex comprising a ligand L_ahaving a structure of Formula 1 and an organic electroluminescent device and compound composition comprising the metal complex.

BACKGROUND

Organic electronic devices include, but are not limited to, the following types: organic light-emitting diodes (OLEDs), organic field-effect transistors (O-FETs), organic light-emitting transistors (OLETs), organic photovoltaic devices (OPVs), dye-sensitized solar cells (DSSCs), organic optical detectors, organic photoreceptors, organic field-quench devices (OFQDs), light-emitting electrochemical cells (LECs), organic laser diodes and organic plasmon emitting devices.

In 1987, Tang and Van Slyke of Eastman Kodak reported a bilayer organic electroluminescent device, which includes an arylamine hole transporting layer and a tris-8-hydroxyquinolato-aluminum layer as the electron and emitting layer (Applied Physics Letters, 1987, 51 (12): 913-915). Once a bias is applied to the device, green light was emitted from the device. This device laid the foundation for the development of modern organic light-emitting diodes (OLEDs). State-of-the-art OLEDs may include multiple layers such as charge injection and transporting layers, charge and exciton blocking layers, and one or multiple emissive layers between the cathode and anode. Since the OLED is a self-emitting solid state device, it offers tremendous potential for display and lighting applications. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on flexible substrates.

The OLED can be categorized as three different types according to its emitting mechanism. The OLED invented by Tang and van Slyke is a fluorescent OLED. It only utilizes singlet emission. The triplets generated in the device are wasted through nonradiative decay channels. Therefore, the internal quantum efficiency (IQE) of the fluorescent OLED is only 25%. This limitation hindered the commercialization of OLED. In 1997, Forrest and Thompson reported phosphorescent OLED, which uses triplet emission from heavy metal containing complexes as the emitter. As a result, both singlet and triplets can be harvested, achieving 100% IQE. The discovery and development of phosphorescent OLED contributed directly to the commercialization of active-matrix OLED (AMOLED) due to its high efficiency. Recently, Adachi achieved high efficiency through thermally activated delayed fluorescence (TADF) of organic compounds. These emitters have small singlet-triplet gap that makes the transition from triplet back to singlet possible. In the TADF device, the triplet excitons can go through reverse intersystem crossing to generate singlet excitons, resulting in high IQE.

OLEDs can also be classified as small molecule and polymer OLEDs according to the forms of the materials used. A small molecule refers to any organic or organometallic material that is not a polymer. The molecular weight of the small molecule can be large as long as it has well defined structure. Dendrimers with well-defined structures are considered as small molecules. Polymer OLEDs include conjugated polymers and non-conjugated polymers with pendant emitting groups. Small molecule OLED can become the polymer OLED if post polymerization occurred during the fabrication process.

There are various methods for OLED fabrication. Small molecule OLEDs are generally fabricated by vacuum thermal evaporation. Polymer OLEDs are fabricated by solution process such as spin-coating, inkjet printing, and slit printing. If the material can be dissolved or dispersed in a solvent, the small molecule OLED can also be produced by solution process.

The emitting color of the OLED can be achieved by emitter structural design. An OLED may include one emitting layer or a plurality of emitting layers to achieve desired spectrum. In the case of green, yellow, and red OLEDs, phosphorescent emitters have successfully reached commercialization. Blue phosphorescent device still suffers from non-saturated blue color, short device lifetime, and high operating voltage. Commercial full-color OLED displays normally adopt a hybrid strategy, using fluorescent blue and phosphorescent yellow, or red and green. At present, efficiency roll-off of phosphorescent OLEDs at high brightness remains a problem. In addition, it is desirable to have more saturated emitting color, higher efficiency, and longer device lifetime.

US2014021447A1 discloses a metal complex having the following structure:

text missing or illegible when filed

wherein Z is a single bond or is absent, and further discloses the following iridium complex:

text missing or illegible when filed

This application discloses a metal complex in which a carbazole group is joined at position 5 of pyridine in a phenyl-pyridine ligand. However, this application has neither disclosed nor taught a metal complex in which a particular substituent is joined at position 4 of pyridine in a fused six-five-six member ring-pyridine ligand and an effect of the metal complex on device performance.

U.S. Pat. No. 7,816,016B1 discloses a metal complex having the following structure:

text missing or illegible when filed

wherein R¹is selected from a structure such as indole, indoline, carbazole, tetrahydrocarbazole, phenanthroline, phenazine, phenanthridine, quinoxaline, pyrrole or CHAr₂, and further discloses a metal complex comprising a fluorine-substituted phenylpyridine ligand where a carbazole is substituted at position 4 of the pyridine. This application discloses a metal complex, wherein in the phenyl-pyridine ligand, a heteroaryl group such as carbazole is joined at position 4 of the pyridine and a fluorine substitution exists on the phenyl. However, this application has not disclosed the data of an organic electroluminescent device and has neither disclosed nor taught a metal complex in which a particular substituent is joined at position 4 of pyridine in a ligand with another structure, such as a fused six-five-six member ring-pyridine ligand, and an effect of the metal complex on device performance.

SUMMARY

The present disclosure aims to provide a series of metal complexes each comprising a ligand L_ahaving a structure of Formula 1 to solve at least part of the above-mentioned problems. These metal complexes may be used as light-emitting materials in electroluminescent devices. When applied to the electroluminescent devices, these novel compounds can provide better device performance such as improved device efficiency and an extended device lifetime and significantly improve the overall performance of the devices.

According to an embodiment of the present disclosure, disclosed is a metal complex comprising a metal M and a ligand L_acoordinated to the metal M, wherein L_ahas a structure represented by Formula 1:

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wherein

the metal M is selected from a metal with a relative atomic mass greater than 40;

Z is selected from the group consisting of O, S, Se, NR′, CR′R′ and SiR′R′; when two R′ are present at the same time, the two R′ are the same or different;

the substituent R_yrepresents mono-substitution, multiple substitutions or non-substitution;

X₁to X₈are, at each occurrence identically or differently, selected from C, CR_xor N, and at least one of X₁to X₄is selected from C and joined to pyridine in Formula 1;

the substituent R_nhas a structure represented by Formula 2:

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wherein in Formula 2,

the substituents RA and RB represent, at each occurrence identically or differently, mono-substitution, multiple substitutions or non-substitution;

the ring A and the ring B are identically or differently selected from a carbocyclic ring having 3 to 30 ring atoms or a heterocyclic ring having 3 to 30 ring atoms;

A₁, A₂, B₁, B₂and E are, at each occurrence identically or differently, selected from C, N, B, P, CR′″, SiR′″ or GeR′″;

L is selected from a single bond, O, S, SO₂, Se, NR″, CR″R″, SiR″R″, GeR″R″, BR″, PR″, P(O)R″, R″C═CR″, substituted or unsubstituted alkylene having 1 to 20 carbon atoms, substituted or unsubstituted heteroalkylene having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkylene having 3 to 20 carbon atoms, substituted or unsubstituted heterocyclylene having 3 to 20 ring atoms, substituted or unsubstituted arylene having 6 to 30 carbon atoms, substituted or unsubstituted heteroarylene having 3 to 30 carbon atoms or a combination thereof;

the substituents R′, R″, R′″, R_x, R_y, R_Aand R_Bare, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1 to 20 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 20 ring atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 20 carbon atoms, substituted or unsubstituted alkynyl having 2 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, substituted or unsubstituted arylgermanyl having 6 to 20 carbon atoms, substituted or unsubstituted amino having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a hydroxyl group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group and combinations thereof;

“*” represents a position where Formula 2 is joined; and

adjacent substituents R′, R_x, R″, R′″, R_A, R_B, R_ycan be optionally joined to form a ring.

According to another embodiment of the present disclosure, further disclosed is an electroluminescent device comprising an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein at least one layer of the organic layer comprises the metal complex in the preceding embodiment.

According to another embodiment of the present disclosure, further disclosed is a compound composition comprising the metal complex in the preceding embodiment.

The present disclosure discloses a series of metal complexes each comprising a ligand L_ahaving a structure of Formula 1. These novel metal complexes may be used as light-emitting materials in electroluminescent devices. When applied to the electroluminescent devices, these metal complexes can achieve very good device performance such as improved device efficiency and an extended device lifetime and significantly improve the overall performance of the devices. These metal complexes have a huge application prospect in aspects of white and low blue light sources.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of an organic light-emitting apparatus that may comprise a metal complex and a compound composition disclosed herein.

FIG. 2 is a schematic diagram of another organic light-emitting apparatus that may comprise a metal complex and a compound composition disclosed herein.

DETAILED DESCRIPTION

OLEDs can be fabricated on various types of substrates such as glass, plastic, and metal foil. FIG. 1 schematically shows an organic light-emitting device 100 without limitation. The figures are not necessarily drawn to scale. Some of the layers in the figures can also be omitted as needed. Device 100 may include a substrate 101, an anode 110, a hole injection layer 120, a hole transport layer 130, an electron blocking layer 140, an emissive layer 150, a hole blocking layer 160, an electron transport layer 170, an electron injection layer 180 and a cathode 190. Device 100 may be fabricated by depositing the layers described in order. The properties and functions of these various layers, as well as example materials, are described in more detail in U.S. Pat. No. 7,279,704 at cols. 6-10, the contents of which are incorporated by reference herein in its entirety.

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 herein 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 herein in its entirety. Examples of host materials are disclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which is incorporated by reference herein 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 herein in its entirety. U.S. Pat. Nos. 5,703,436 and 5,707,745, which are incorporated by reference herein in their entireties, disclose examples of cathodes including composite 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 are 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 herein in their entireties. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004/0174116, which is incorporated by reference herein 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 herein in its entirety.

The layered structure described above is provided by way of non-limiting examples. Functional OLEDs may be achieved by combining the various layers described in different ways, or layers may be omitted entirely. It may also include other layers not specifically described. Within each layer, a single material or a mixture of multiple materials can be used to achieve optimum performance. Any functional layer may include several sublayers. For example, the emissive layer may have two layers of different emitting materials to achieve desired emission spectrum.

In one embodiment, an OLED may be described as having an “organic layer” disposed between a cathode and an anode. This organic layer may include a single layer or multiple layers.

An OLED can be encapsulated by a barrier layer. FIG. 2 schematically shows an organic light emitting device 200 without limitation. FIG. 2 differs from FIG. 1 in that the organic light emitting device include a barrier layer 102, which is above the cathode 190, to protect it from harmful species from the environment such as moisture and oxygen. Any material that can provide the barrier function can be used as the barrier layer such as glass or organic-inorganic hybrid layers. The barrier layer should be placed directly or indirectly outside of the OLED device. Multilayer thin film encapsulation was described in U.S. Pat. No. 7,968,146, which is incorporated by reference herein in its entirety.

Devices fabricated in accordance with embodiments of the present disclosure can be incorporated into a wide variety of consumer products that have one or more of the electronic component modules (or units) incorporated therein. Some examples of such consumer products include flat panel displays, monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully or partially transparent displays, flexible displays, smart phones, tablets, phablets, wearable devices, smart watches, laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, vehicles displays, and vehicle tail lights.

The materials and structures described herein may be used in other organic electronic devices listed above.

As used herein, “top” means furthest away from the substrate, while “bottom” means closest to the substrate. Where a first layer is described as “disposed over” a second layer, the first layer is disposed further away from the substrate. There may be other layers between the first and second layers, unless it is specified that the first layer is “in contact with” the second layer. For example, a cathode may be described as “disposed over” an anode, even though there are various organic layers in between.

As used herein, “solution processible” means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed that the ligand directly contributes to the photoactive properties of an emissive material. A ligand may be referred to as “ancillary” when it is believed that the ligand does not contribute to the photoactive properties of an emissive material, although an ancillary ligand may alter the properties of a photoactive ligand.

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

On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the transition 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 to convert between energy states. 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. If the reverse intersystem crossing (RISC) 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 25% of the spin statistics limit for electrically generated excitons.

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 (ΔE_S-T). Organic, non-metal containing, donor-acceptor luminescent materials may be able to achieve this. The emission in these materials is generally characterized as a donor-acceptor charge-transfer (CT) type emission. The spatial separation of the HOMO and LUMO in these donor-acceptor type compounds generally results in small ΔE_S-T. These states may involve CT states. Generally, 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 rings.

Definition of Terms of Substituents

Halogen or halide—as used herein includes fluorine, chlorine, bromine, and iodine.

Alkyl—as used herein includes both straight and branched chain alkyl groups. Alkyl may be alkyl having 1 to 20 carbon atoms, preferably alkyl having 1 to 12 carbon atoms, and more preferably alkyl having 1 to 6 carbon atoms. Examples of alkyl groups include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, a neopentyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 1-pentylhexyl group, a 1-butylpentyl group, a 1-heptyloctyl group, and a 3-methylpentyl group. Of the above, preferred are a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, an s-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, a neopentyl group, and an n-hexyl group. Additionally, the alkyl group may be optionally substituted.

Cycloalkyl—as used herein includes cyclic alkyl groups. The cycloalkyl groups may be those having 3 to 20 ring carbon atoms, preferably those having 4 to 10 carbon atoms. Examples of cycloalkyl include cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4,4-dimethylcylcohexyl, 1-adamantyl, 2-adamantyl, 1-norbornyl, 2-norbornyl, and the like. Of the above, preferred are cyclopentyl, cyclohexyl, 4-methylcyclohexyl, and 4,4-dimethylcylcohexyl. Additionally, the cycloalkyl group may be optionally substituted.

Heteroalkyl—as used herein, includes a group formed by replacing one or more carbons in an alkyl chain with a hetero-atom(s) selected from the group consisting of a nitrogen atom, an oxygen atom, a sulfur atom, a selenium atom, a phosphorus atom, a silicon atom, a germanium atom, and a boron atom. Heteroalkyl may be those having 1 to 20 carbon atoms, preferably those having 1 to 10 carbon atoms, and more preferably those having 1 to 6 carbon atoms. Examples of heteroalkyl include methoxymethyl, ethoxymethyl, ethoxyethyl, methylthiomethyl, ethylthiomethyl, ethylthioethyl, methoxymethoxymethyl, ethoxymethoxymethyl, ethoxyethoxyethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, mercaptomethyl, mercaptoethyl, mercaptopropyl, aminomethyl, aminoethyl, aminopropyl, dimethylaminomethyl, trimethylgermanylmethyl, trimethylgermanylethyl, trimethylgermanylisopropyl, dimethylethylgermanylmethyl, dimethylisopropylgermanylmethyl, tert-butylmethylgermanylmethyl, triethylgermanylmethyl, triethylgermanylethyl, triisopropylgermanylmethyl, triisopropylgermanylethyl, trimethylsilylmethyl, trimethylsilylethyl, and trimethylsilylisopropyl, triisopropylsilylmethyl, triisopropylsilylethyl. Additionally, the heteroalkyl group may be optionally substituted.

Alkenyl—as used herein includes straight chain, branched chain, and cyclic alkene groups. Alkenyl may be those having 2 to 20 carbon atoms, preferably those having 2 to 10 carbon atoms. Examples of alkenyl include vinyl, 1-propenyl group, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butandienyl, 1-methylvinyl, styryl, 2,2-diphenylvinyl, 1,2-diphenylvinyl, 1-methylallyl, 1,1-dimethylallyl, 2-methylallyl, 1-phenylallyl, 2-phenylallyl, 3-phenylallyl, 3,3-diphenylallyl, 1,2-dimethylallyl, 1-phenyl-1-butenyl, 3-phenyl-1-butenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, cycloheptenyl, cycloheptatrienyl, cyclooctenyl, cyclooctatetraenyl, and norbornenyl. Additionally, the alkenyl group may be optionally substituted.

Alkynyl—as used herein includes straight chain alkynyl groups. Alkynyl may be those having 2 to 20 carbon atoms, preferably those having 2 to 10 carbon atoms. Examples of alkynyl groups include ethynyl, propynyl, propargyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3,3-dimethyl-1-butynyl, 3-ethyl-3-methyl-1-pentynyl, 3,3-diisopropyl-1-pentynyl, phenylethynyl, phenylpropynyl, etc. Of the above, preferred are ethynyl, propynyl, propargyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, and phenylethynyl. Additionally, the alkynyl group may be optionally substituted.

Aryl or an aromatic group—as used herein includes non-condensed and condensed systems. Aryl may be those having 6 to 30 carbon atoms, preferably those having 6 to 20 carbon atoms, and more preferably those having 6 to 12 carbon atoms. Examples of aryl groups include phenyl, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene, preferably phenyl, biphenyl, terphenyl, triphenylene, fluorene, and naphthalene. Examples of non-condensed aryl groups include phenyl, biphenyl-2-yl, biphenyl-3-yl, biphenyl-4-yl, p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl, m-terphenyl-2-yl, o-tolyl, m-tolyl, p-tolyl, p-(2-phenylpropyl)phenyl, 4′-methylbiphenylyl, 4″-t-butyl-p-terphenyl-4-yl, o-cumenyl, m-cumenyl, p-cumenyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesityl, and m-quarterphenyl. Additionally, the aryl group may be optionally substituted.

Heterocyclic groups or heterocycle—as used herein include non-aromatic cyclic groups. Non-aromatic heterocyclic groups include saturated heterocyclic groups having 3 to 20 ring atoms and unsaturated non-aromatic heterocyclic groups having 3 to 20 ring atoms, where at least one ring atom is selected from the group consisting of a nitrogen atom, an oxygen atom, a sulfur atom, a selenium atom, a silicon atom, a phosphorus atom, a germanium atom, and a boron atom. Preferred non-aromatic heterocyclic groups are those having 3 to 7 ring atoms, each of which includes at least one hetero-atom such as nitrogen, oxygen, silicon, or sulfur. Examples of non-aromatic heterocyclic groups include oxiranyl, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl, dioxolanyl, dioxanyl, aziridinyl, dihydropyrrolyl, tetrahydropyrrolyl, piperidinyl, oxazolidinyl, morpholinyl, piperazinyl, oxepinyl, thiepinyl, azepinyl, and tetrahydrosilolyl. Additionally, the heterocyclic group may be optionally substituted.

Heteroaryl—as used herein, includes non-condensed and condensed hetero-aromatic groups having 1 to 5 hetero-atoms, where at least one hetero-atom is selected from the group consisting of a nitrogen atom, an oxygen atom, a sulfur atom, a selenium atom, a silicon atom, a phosphorus atom, a germanium atom, and a boron atom. A hetero-aromatic group is also referred to as heteroaryl. Heteroaryl may be those having 3 to 30 carbon atoms, preferably those having 3 to 20 carbon atoms, and more preferably those having 3 to 12 carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridoindole, 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, 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.

Alkoxy—as used herein, is represented by —O-alkyl, —O-cycloalkyl, —O-heteroalkyl, or —O-heterocyclic group. Examples and preferred examples of alkyl, cycloalkyl, heteroalkyl, and heterocyclic groups are the same as those described above. Alkoxy groups may be those having 1 to 20 carbon atoms, preferably those having 1 to 6 carbon atoms. Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, tetrahydrofuranyloxy, tetrahydropyranyloxy, methoxypropyloxy, ethoxyethyloxy, methoxymethyloxy, and ethoxymethyloxy. Additionally, the alkoxy group may be optionally substituted.

Aryloxy—as used herein, is represented by —O-aryl or —O-heteroaryl. Examples and preferred examples of aryl and heteroaryl are the same as those described above. Aryloxy groups may be those having 6 to 30 carbon atoms, preferably those having 6 to 20 carbon atoms. Examples of aryloxy groups include phenoxy and biphenyloxy. Additionally, the aryloxy group may be optionally substituted.

Arylalkyl—as used herein, contemplates alkyl substituted with an aryl group. Arylalkyl may be those having 7 to 30 carbon atoms, preferably those having 7 to 20 carbon atoms, and more preferably those having 7 to 13 carbon atoms. Examples of arylalkyl groups include benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, 2-phenylisopropyl, phenyl-t-butyl, alpha-naphthylmethyl, 1-alpha-naphthylethyl, 2-alpha-naphthylethyl, 1-alpha-naphthylisopropyl, 2-alpha-naphthylisopropyl, beta-naphthylmethyl, 1-beta-naphthylethyl, 2-beta-naphthylethyl, 1-beta-naphthylisopropyl, 2-beta-naphthylisopropyl, p-methylbenzyl, m-methylbenzyl, o-methylbenzyl, p-chlorobenzyl, m-chlorobenzyl, o-chlorobenzyl, p-bromobenzyl, m-bromobenzyl, o-bromobenzyl, p-iodobenzyl, m-iodobenzyl, o-iodobenzyl, p-hydroxybenzyl, m-hydroxybenzyl, o-hydroxybenzyl, p-aminobenzyl, m-aminobenzyl, o-aminobenzyl, p-nitrobenzyl, m-nitrobenzyl, o-nitrobenzyl, p-cyanobenzyl, m-cyanobenzyl, o-cyanobenzyl, 1-hydroxy-2-phenylisopropyl, and 1-chloro-2-phenylisopropyl. Of the above, preferred are benzyl, p-cyanobenzyl, m-cyanobenzyl, o-cyanobenzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, and 2-phenylisopropyl. Additionally, the arylalkyl group may be optionally substituted.

Alkylsilyl—as used herein, contemplates a silyl group substituted with an alkyl group. Alkylsilyl groups may be those having 3 to 20 carbon atoms, preferably those having 3 to 10 carbon atoms. Examples of alkylsilyl groups include trimethylsilyl, triethylsilyl, methyldiethylsilyl, ethyldimethylsilyl, tripropylsilyl, tributylsilyl, triisopropylsilyl, methyldiisopropylsilyl, dimethylisopropylsilyl, tri-t-butylsilyl, triisobutylsilyl, dimethyl t-butylsilyl, and methyldi-t-butylsilyl. Additionally, the alkylsilyl group may be optionally substituted.

Arylsilyl—as used herein, contemplates a silyl group substituted with an aryl group. Arylsilyl groups may be those having 6 to 30 carbon atoms, preferably those having 8 to 20 carbon atoms. Examples of arylsilyl groups include triphenylsilyl, phenyldibiphenylylsilyl, diphenylbiphenylsilyl, phenyldiethylsilyl, diphenylethylsilyl, phenyldimethylsilyl, diphenylmethylsilyl, phenyldiisopropylsilyl, diphenylisopropylsilyl, diphenylbutylsilyl, diphenylisobutylsilyl, diphenyl t-butylsilyl. Additionally, the arylsilyl group may be optionally substituted.

Alkylgermanyl—as used herein contemplates germanyl substituted with an alkyl group. The alkylgermanyl may be those having 3 to 20 carbon atoms, preferably those having 3 to 10 carbon atoms. Examples of alkylgermanyl include trimethylgermanyl, triethylgermanyl, methyldiethylgermanyl, ethyldimethylgermanyl, tripropylgermanyl, tributylgermanyl, triisopropylgermanyl, methyldiisopropylgermanyl, dimethylisopropylgermanyl, tri-t-butylgermanyl, triisobutylgermanyl, dimethyl-t-butylgermanyl, and methyldi-t-butylgermanyl. Additionally, the alkylgermanyl may be optionally substituted.

Arylgermanyl—as used herein contemplates a germanyl substituted with at least one aryl group or heteroaryl group. Arylgermanyl may be those having 6 to 30 carbon atoms, preferably those having 8 to 20 carbon atoms. Examples of arylgermanyl include triphenylgermanyl, phenyldibiphenylylgermanyl, diphenylbiphenylgermanyl, phenyldiethylgermanyl, diphenylethylgermanyl, phenyldimethylgermanyl, diphenylmethylgermanyl, phenyldiisopropylgermanyl, diphenylisopropylgermanyl, diphenylbutylgermanyl, diphenylisobutylgermanyl, and diphenyl-t-butylgermanyl. Additionally, the arylgermanyl may be optionally substituted.

The term “aza” in azadibenzofuran, azadibenzothiophene, etc. means that one or more of C—H groups in the respective aromatic fragment are replaced by a nitrogen atom. For example, azatriphenylene encompasses dibenzo[f,h]quinoxaline, dibenzo[f,h]quinoline and other analogs with two or more nitrogens in the ring system. 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.

In the present disclosure, unless otherwise defined, when any term of the group consisting of substituted alkyl, substituted cycloalkyl, substituted heteroalkyl, substituted heterocyclic group, substituted arylalkyl, substituted alkoxy, substituted aryloxy, substituted alkenyl, substituted alkynyl, substituted aryl, substituted heteroaryl, substituted alkylsilyl, substituted arylsilyl, substituted alkylgermanyl, substituted arylgermanyl, substituted amino, substituted acyl, substituted carbonyl, a substituted carboxylic acid group, a substituted ester group, substituted sulfinyl, substituted sulfonyl, and substituted phosphino is used, it means that any group of alkyl, cycloalkyl, heteroalkyl, heterocyclic group, arylalkyl, alkoxy, aryloxy, alkenyl, alkynyl, aryl, heteroaryl, alkylsilyl, arylsilyl, alkylgermanyl, arylgermanyl, amino, acyl, carbonyl, a carboxylic acid group, an ester group, sulfinyl, sulfonyl, and phosphino may be substituted with one or more moieties selected from the group consisting of deuterium, halogen, unsubstituted alkyl having 1 to 20 carbon atoms, unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, unsubstituted heteroalkyl having 1 to 20 carbon atoms, an unsubstituted heterocyclic group having 3 to 20 ring atoms, unsubstituted arylalkyl having 7 to 30 carbon atoms, unsubstituted alkoxy having 1 to 20 carbon atoms, unsubstituted aryloxy having 6 to 30 carbon atoms, unsubstituted alkenyl having 2 to 20 carbon atoms, unsubstituted alkynyl having 2 to 20 carbon atoms, unsubstituted aryl having 6 to 30 carbon atoms, unsubstituted heteroaryl having 3 to 30 carbon atoms, unsubstituted alkylsilyl having 3 to 20 carbon atoms, unsubstituted arylsilyl having 6 to 20 carbon atoms, unsubstituted alkylgermanyl having 3 to 20 carbon atoms, unsubstituted arylgermanyl group having 6 to 20 carbon atoms, unsubstituted amino having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a hydroxyl group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group, and combinations thereof.

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 an attached fragment are considered to be equivalent.

In the compounds mentioned in the present disclosure, hydrogen atoms may be partially or fully replaced by deuterium. Other atoms such as carbon and nitrogen can also be replaced by their other stable isotopes. The replacement by other stable isotopes in the compounds may be preferred due to its enhancements of device efficiency and stability.

In the compounds mentioned in the present disclosure, multiple substitution refers to a range that includes a di-substitution, up to the maximum available substitution. When substitution in the compounds mentioned in the present disclosure represents multiple substitution (including di-, tri-, and tetra-substitutions, etc.), that means the substituent may exist at a plurality of available substitution positions on its linking structure, the substituents present at a plurality of available substitution positions may be the same structure or different structures.

In the compounds mentioned in the present disclosure, adjacent substituents in the compounds cannot be joined to form a ring unless otherwise explicitly defined, for example, adjacent substituents can be optionally joined to form a ring. In the compounds mentioned in the present disclosure, the expression that adjacent substituents can be optionally joined to form a ring includes a case where adjacent substituents may be joined to form a ring and a case where adjacent substituents are not joined to form a ring. When adjacent substituents can be optionally joined to form a ring, the ring formed may be monocyclic or polycyclic (including spirocyclic, endocyclic, fusedcyclic, and etc.), as well as alicyclic, heteroalicyclic, aromatic, or heteroaromatic. In such expression, adjacent substituents may refer to substituents bonded to the same atom, substituents bonded to carbon atoms which are directly bonded to each other, or substituents bonded to carbon atoms which are more distant from each other. Preferably, adjacent substituents refer to substituents bonded to the same carbon atom and substituents bonded to carbon atoms which are directly bonded to each other.

The expression that adjacent substituents can be optionally joined to form a ring is also intended to mean that two substituents bonded to the same carbon atom are joined to each other via a chemical bond to form a ring, which can be exemplified by the following formula:

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The expression that adjacent substituents can be optionally joined to form a ring is also intended to mean that two substituents bonded to carbon atoms which are directly bonded to each other are joined to each other via a chemical bond to form a ring, which can be exemplified by the following formula:

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The expression that adjacent substituents can be optionally joined to form a ring is also intended to mean that two substituents bonded to a further distant carbon atom are joined to each other via a chemical bond to form a ring, which can be exemplified by the following formula:

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Furthermore, the expression that adjacent substituents can be optionally joined to form a ring is also intended to mean that, in the case where one of the two substituents bonded to carbon atoms which are directly bonded to each other represents hydrogen, the second substituent is bonded at a position at which the hydrogen atom is bonded, thereby forming a ring. This is exemplified by the following formula:

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wherein

the metal M is selected from a metal with a relative atomic mass greater than 40;

Z is selected from the group consisting of O, S, Se, NR′, CR′R′ and SiR′R′; when two R′ are present at the same time, the two R′ are the same or different;

the substituent R_yrepresents mono-substitution, multiple substitutions or non-substitution;

X₁to X₈are, at each occurrence identically or differently, selected from C, CR_xor N; and two of X₁to X₄are selected from C, one C is joined to pyridine in Formula 1, and the other C is coordinated to the metal to form a metal-carbon bond;

the substituent R_ahas a structure represented by Formula 2:

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wherein in Formula 2,

the substituents R_Aand R_Brepresent, at each occurrence identically or differently, mono-substitution, multiple substitutions or non-substitution;

the ring A and the ring B are identically or differently selected from a carbocyclic ring having 3 to 30 ring atoms or a heterocyclic ring having 3 to 30 ring atoms;

A₁, A₂, B₁, B₂and E are, at each occurrence identically or differently, selected from C, N, B, P, CR′″, SiR′″ or GeR′″;

“*” represents a position where Formula 2 is joined; and

adjacent substituents R′, R_x, R″, R′″, R_A, R_B, R_ycan be optionally joined to form a ring.

In the present disclosure, the expression that “L is selected from a single bond” is intended to mean that Formula 2 has the following structure:

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wherein A₁, A₂, B₁, B₂, E, the ring A, the ring B, R_Aand R_Bare defined as described herein.

In the present disclosure, the expression that “adjacent substituents R′, R_x, R″, R′″, R_A, R_B, R_ycan be optionally joined to form a ring” is intended to mean that any one or more of groups of adjacent substituents, such as two substituents R′, two substituents R_x, two substituents R_A, two substituents R_B, two substituents R_y, substituents R′ and R_x, substituents R′ and R_y, substituents R_Aand R_B, substituents R_Aand R″, substituents R″ and R_B, substituents R_Aand R_yand substituents R_yand R_B, can be joined to form a ring. Obviously, it is also possible that none of these substituents are joined to form a ring.

According to an embodiment of the present disclosure, the ligand L_ais, at each occurrence identically or differently, selected from any one of the group consisting of the following structures:

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wherein

Z is selected from the group consisting of O, S, Se, NR′, CR′R′ and SiR′R′; when two R′ are present at the same time, the two R′ are the same or different;

the substituent R_yrepresents mono-substitution, multiple substitutions or non-substitution; in Formula 1a and Formula 1c, X₃to X₅are, at each occurrence identically or differently, selected from CR_xor N;

in Formula 1b, X₁and X₄to X₅are, at each occurrence identically or differently, selected from CR_xor N;

in Formula 1d and Formula 1e, X₁, X₂, and X₅to X₅are, at each occurrence identically or differently, selected from CR_xor N;

the substituent R_nhas a structure represented by Formula 2:

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wherein in Formula 2,

the substituents R_Aand R_Brepresent, at each occurrence identically or differently, mono-substitution, multiple substitutions or non-substitution;

the ring A and the ring B are identically or differently selected from a carbocyclic ring having 3 to 30 ring atoms or a heterocyclic ring having 3 to 30 ring atoms;

A₁, A₂, B₁, B₂and E are, at each occurrence identically or differently, selected from C, N, B, P, CR′″, SiR′″ or GeR′″;

“*” represents a position where Formula 2 is joined; and

adjacent substituents R′, R_x, R″, R′″, R_A, R_B, R_ycan be optionally joined to form a ring.

According to an embodiment of the present disclosure, the metal complex has a general formula of M(L_a)_m(L_b)_n(L_c)_q;

wherein

the metal M is selected from a metal with a relative atomic mass greater than 40; preferably, M is, at each occurrence identically or differently, selected from the group consisting of Cu, Ag, Au, Ru, Rh, Pd, Os, Ir and Pt; more preferably, M is, at each occurrence identically or differently, selected from Pt or Ir;

L_a, L_band L_care a first ligand, a second ligand and a third ligand coordinated to the metal M, respectively, and L_cis the same as or different from L_aor L_b; wherein L_a, L_band L_ccan be optionally joined to form a multidentate ligand; for example, any two of the ligands L_a, L_band L_care joined to form a tetradentate ligand, the ligands L_a, L_band L_care joined to form a hexadentate ligand, or none of the ligands L_a, L_band L_care joined to form a multidentate ligand;

m is selected from 1, 2 or 3, n is selected from 0, 1 or 2, q is selected from 0, 1 or 2, and m+n+q equals to the oxidation state of the metal M; when m is greater than or equal to 2, multiple L_aare the same or different; when n is equal to 2, two L_bare the same or different; when q is equal to 2, two L_care the same or different;

L_band L_care, at each occurrence identically or differently, selected from a structure represented by any one of the group consisting of:

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wherein

the substituents R_aand R_brepresent, at each occurrence identically or differently, mono-substitution, multiple substitutions or non-substitution;

X_bis, at each occurrence identically or differently, selected from the group consisting of: O, S, Se, NR_N1and CR_C1R_C2;

the substituents R_a, R_b, R_c, R_N1, R_C1and R_C2are, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1 to 20 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 20 ring atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 20 carbon atoms, substituted or unsubstituted alkynyl having 2 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, substituted or unsubstituted arylgermanyl having 6 to 20 carbon atoms, substituted or unsubstituted amino having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a hydroxyl group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group and combinations thereof, and

adjacent substituents R_a, R_b, R_c, R_N1, R_C1and R_C2can be optionally joined to form a ring.

In the present disclosure, the expression that “adjacent substituents R_a, R_b, R_c, R_N1, R_C1and R_C2can be optionally joined to form a ring” is intended to mean that any one or more of groups of adjacent substituents, such as two substituents R_a, two substituents R_b, substituents R_aand R_b, substituents R_aand R_c, substituents R_band R_c, substituents R_aand R_N1, substituents R_band R_N1, substituents R_aand R_C1, substituents R_aand R_C2, substituents R_band R_C1, substituents R_band R_C2and substituents R_C1and R_C2, can be joined to form a ring. Obviously, it is also possible that none of these substituents are joined to form a ring.

According to an embodiment of the present disclosure, the metal complex has a general formula of Ir(L_a)_m(L_b)_3-mand is represented by Formula 3:

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wherein

m is selected from 1, 2 or 3; when m is selected from 1, two L_bare the same or different; when m is selected from 2 or 3, multiple L_aare the same or different;

Z is selected from the group consisting of O, S, Se, NR′, CR′R′ and SiR′R′; when two R′ are present at the same time, the two R′ are the same or different;

the substituent R_yrepresents mono-substitution, multiple substitutions or non-substitution;

X₃to X₅are, at each occurrence identically or differently, selected from CR_xor N;

the substituent R_nhas a structure represented by Formula 2:

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wherein in Formula 2,

the substituents R_Aand R_Brepresent, at each occurrence identically or differently, mono-substitution, multiple substitutions or non-substitution;

the ring A and the ring B are identically or differently selected from a carbocyclic ring having 3 to 30 ring atoms or a heterocyclic ring having 3 to 30 ring atoms;

A₁, A₂, B₁, B₂and E are, at each occurrence identically or differently, selected from C, N, B, P, CR′″, SiR′″ or GeR′″;

the substituents R₁to R₈, R′, R″, R′″, R_x, R_y, R_Aand R_Bare, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1 to 20 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 20 ring atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 20 carbon atoms, substituted or unsubstituted alkynyl having 2 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, substituted or unsubstituted arylgermanyl having 6 to 20 carbon atoms, substituted or unsubstituted amino having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a hydroxyl group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group and combinations thereof,

“*” represents a position where Formula 2 is joined;

adjacent substituents R′, R_x, R″, R′″, R_A, R_B, R_ycan be optionally joined to form a ring; and

adjacent substituents R₁to R₈can be optionally joined to form a ring.

In this embodiment, the expression that “adjacent substituents R₁to R₈can be optionally joined to form a ring” is intended to mean that any one or more of groups of any two adjacent substituents of R₁to R₈can be joined to form a ring. Obviously, it is also possible that none of these substituents are joined to form a ring.

According to an embodiment of the present disclosure, Z is selected from 0 or S.

According to an embodiment of the present disclosure, Z is selected from 0.

According to an embodiment of the present disclosure, X₁to X₅are, at each occurrence identically or differently, selected from CR_x.

According to an embodiment of the present disclosure, X₃to X₅are, at each occurrence identically or differently, selected from CR_x.

According to an embodiment of the present disclosure, at least one of X₁to X₅is selected from N. For example, one of X₁to X₅is selected from N, or two of X₁to X₅are selected from N.

According to an embodiment of the present disclosure, at least one of X₃to X₅is selected from N. For example, one of X₃to X₅is selected from N, or two of X₃to X₅are selected from N.

According to an embodiment of the present disclosure, the substituent R_xis, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituent R_xis, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 6 ring carbon atoms, substituted or unsubstituted aryl having 6 to 12 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 12 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 6 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 6 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituent R_xis, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, cyclopentyl, cyclohexyl, deuterated methyl, deuterated ethyl, deuterated propyl, deuterated isopropyl, deuterated n-butyl, deuterated isobutyl, deuterated t-butyl, deuterated cyclopentyl, deuterated cyclohexyl, phenyl, biphenyl, pyridyl, trimethylsilyl, trimethylgermanyl and combinations thereof, optionally, hydrogens in the above groups can be partially or fully deuterated.

According to an embodiment of the present disclosure, the substituent R_nhas a structure represented by Formula 4:

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wherein

A₃to A₆are, at each occurrence identically or differently, selected from CR_Aor N;

B₃to B₆are, at each occurrence identically or differently, selected from CR_Bor N;

L is selected from a single bond, O, S, SO₂, Se, NR″, CR″R″, SiR″R″, GeR″R″, BR″, PR″, P(O)R″, R″C═CR″, alkylene having 1 to 20 carbon atoms, heteroalkylene having 1 to 20 carbon atoms, cycloalkylene having 3 to 20 carbon atoms, heterocyclylene having 3 to 20 ring atoms, arylene having 6 to 30 carbon atoms, heteroarylene having 3 to 30 carbon atoms or a combination thereof,

the substituents R_A, R_Band R″ are, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1 to 20 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 20 ring atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, substituted or unsubstituted arylgermanyl having 6 to 20 carbon atoms, substituted or unsubstituted amino having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a hydroxyl group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group and combinations thereof,

adjacent substituents R″, R_A, R_Bcan be optionally joined to form a ring; and

“*” represents a position where Formula 4 is joined.

In the present disclosure, the expression that “adjacent substituents R″, R_A, R_Bcan be optionally joined to form a ring” is intended to mean that any one or more of groups of adjacent substituents, such as two substituents R″, two substituents R_A, two substituents R_B, substituents R″ and R_Aand substituents R″ and R_B, can be joined to form a ring. Obviously, it is also possible that none of these substituents are joined to form a ring.

According to an embodiment of the present disclosure, the ring A and the ring B are identically or differently selected from a carbocyclic ring having 6 ring atoms or a heterocyclic ring having 5 to 6 ring atoms.

According to an embodiment of the present disclosure, the ring A and the ring B are identically or differently selected from a benzene ring or a heteroaromatic ring having 5 to 6 ring atoms.

According to an embodiment of the present disclosure, A₃to A₆are, at each occurrence identically or differently, selected from CR_A, and the substituent R_Ais, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, B₃to B₆are, at each occurrence identically or differently, selected from CR_B, and the substituent R_Bis, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituents R_Aand R_Bare, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 6 ring carbon atoms, substituted or unsubstituted aryl having 6 to 12 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 12 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 6 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 6 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituents R_Aand R_Bare, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 12 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 12 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 6 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 6 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituents R_Aand R_Bare, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, neopentyl, cyclopentyl, cyclohexyl, deuterated methyl, deuterated ethyl, deuterated propyl, deuterated isopropyl, deuterated n-butyl, deuterated isobutyl, deuterated t-butyl, deuterated neopentyl, deuterated cyclopentyl, deuterated cyclohexyl, phenyl, pyridyl, trimethylsilyl, trimethylgermanyl and combinations thereof, optionally, hydrogens in the above groups can be partially or fully deuterated.

According to an embodiment of the present disclosure, L is selected from a single bond, O, S, Se, NR″, SiR″R″, GeR″R″, BR″, PR″, P(O)R″, R″C═CR″, substituted or unsubstituted alkylene having 1 to 10 carbon atoms, substituted or unsubstituted heteroalkylene having 1 to 10 carbon atoms, substituted or unsubstituted cycloalkylene having 3 to 10 carbon atoms, substituted or unsubstituted heterocyclylene having 3 to 10 ring atoms, substituted or unsubstituted arylene having 6 to 10 carbon atoms, substituted or unsubstituted heteroarylene having 3 to 10 carbon atoms or a combination thereof.

According to an embodiment of the present disclosure, L is selected from a single bond, O, S, Se, NR″, SiR″R″, GeR″R″, BR″, PR″, P(O)R″, substituted or unsubstituted alkylene having 1 to 10 carbon atoms, substituted or unsubstituted arylene having 6 to 10 carbon atoms, substituted or unsubstituted heteroarylene having 3 to 10 carbon atoms or a combination thereof.

According to an embodiment of the present disclosure, L is selected from a single bond, O, S, NR″, substituted or unsubstituted alkylene having 1 to 10 carbon atoms or substituted or unsubstituted phenylene.

According to an embodiment of the present disclosure, L is selected from a single bond, O, S, NR″ or phenylene.

According to an embodiment of the present disclosure, the substituents R′, R″ and R′″ are, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 6 ring carbon atoms, substituted or unsubstituted aryl having 6 to 12 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 12 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 6 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 6 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituents R′, R″ and R′″ are, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 12 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 12 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 6 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 6 carbon atoms, cyano and combinations thereof.

According to an embodiment of the present disclosure, the substituent R′, R″ and R′″ are, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, fluorine, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, cyclopentyl, cyclohexyl, deuterated methyl, deuterated ethyl, deuterated propyl, deuterated isopropyl, deuterated n-butyl, deuterated isobutyl, deuterated t-butyl, deuterated cyclopentyl, deuterated cyclohexyl, phenyl, pyridyl, trimethylsilyl, trimethylgermanyl and combinations thereof, optionally, hydrogens in the above groups can be partially or fully deuterated.

According to an embodiment of the present disclosure, at least one of X₃to X₅is CR_x, and the substituent R_xis selected from cyano or fluorine.

According to an embodiment of the present disclosure, at least one of X₅to X₅is CR_x, and the substituent R_xis selected from cyano or fluorine.

According to an embodiment of the present disclosure, X₇or X₅is CR_x, and R_xis selected from cyano.

According to an embodiment of the present disclosure, X₇is CR_x, and R_xis selected from fluorine.

According to an embodiment of the present disclosure, at least two of X₃to X₅are selected from CR_x, wherein one substituent R_xis selected from cyano or fluorine, and another substituent R_xis selected from the group consisting of: deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1 to 20 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 20 ring atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, substituted or unsubstituted arylgermanyl having 6 to 20 carbon atoms, cyano, isocyano and combinations thereof.

According to an embodiment of the present disclosure, at least two of X₅to X₅are selected from CR_x, wherein one substituent R_xis selected from cyano or fluorine, and another substituent R_xis selected from the group consisting of: deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3 to 20 carbon atoms, substituted or unsubstituted arylgermanyl having 6 to 20 carbon atoms, cyano, isocyano and combinations thereof.

According to an embodiment of the present disclosure, X₇and X₅are selected from CR_x, wherein one substituent R_xis cyano or fluorine, and the other substituent R_xis selected from the group consisting of: deuterium, fluorine, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, cyano, isocyano and combinations thereof.

According to an embodiment of the present disclosure, R_nis, at each occurrence identically or differently, selected from the group consisting of An₁to An₉₆, wherein the specific structures of An₁to An₉₆are referred to claim 11.

According to an embodiment of the present disclosure, hydrogens in An₁to An₅₂, An₅₄to An₅₈and An₆₁to An₉₆can be partially or fully deuterated.

According to an embodiment of the present disclosure, the substituent R_yis, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted amino having 6 to 20 carbon atoms and combinations thereof.

According to an embodiment of the present disclosure, the substituent R_yis, at each occurrence identically or differently, selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 6 ring carbon atoms, substituted or unsubstituted aryl having 6 to 12 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 12 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 12 carbon atoms and combinations thereof.

According to an embodiment of the present disclosure, at least one substituent R_yis selected from the group consisting of: deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms and combinations thereof.

According to an embodiment of the present disclosure, at least one substituent R_yis selected from the group consisting of: deuterium, fluorine, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, cyclopentyl, cyclohexyl, deuterated methyl, deuterated ethyl, deuterated propyl, deuterated isopropyl, deuterated n-butyl, deuterated isobutyl, deuterated t-butyl, deuterated cyclopentyl, deuterated cyclohexyl, phenyl, pyridyl, trimethylsilyl, trimethylgermanyl and combinations thereof, optionally, hydrogens in the above groups can be partially or fully deuterated.

According to an embodiment of the present disclosure, at least one or at least two of the substituents R₁to R₈are selected from substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms or a combination thereof, and the total number of carbon atoms in all of R₁to R₄and/or R₅to R₈is at least 4.

According to an embodiment of the present disclosure, at least one or at least two of the substituents R₁to R₄are selected from substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms or a combination thereof, and the total number of carbon atoms in all of the substituents R₁to R₄is at least 4.

According to an embodiment of the present disclosure, at least one or at least two of the substituents R₅to R₈are selected from substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms or a combination thereof, and the total number of carbon atoms in all of the substituents R₅to R₈is at least 4.

According to an embodiment of the present disclosure, at least one, at least two, at least three or all of the substituents R₂, R₃, R₆and R₇are selected from the group consisting of: deuterium, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms and combinations thereof.

According to an embodiment of the present disclosure, at least one, at least two, at least three or all of the substituents R₂, R₃, R₆and R₇are selected from the group consisting of: deuterium, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, cyclopentyl, cyclohexyl, neopentyl, t-pentyl and combinations thereof, optionally, hydrogens in the above groups can be partially or fully deuterated.

According to an embodiment of the present disclosure, the ligand L_ais, at each occurrence identically or differently, selected from the group consisting of L_a1to L_a821, wherein the specific structures of L_a1to L_a821are referred to claim 15.

According to an embodiment of the present disclosure, hydrogens in ligands L_a1to L_a821can be partially or fully deuterated.

According to an embodiment of the present disclosure, the ligand L_bis, at each occurrence identically or differently, selected from the group consisting of L_b1to L_b334, wherein the specific structures of L_b1to L_b334are referred to claim 16.

According to an embodiment of the present disclosure, hydrogens in ligands L_b1to L_b334can be partially or fully deuterated.

According to an embodiment of the present disclosure, the ligand L_cis, at each occurrence identically or differently, selected from the group consisting of L_c1to L_c360, wherein the specific structures of L_c1to L_c360are referred to claim 17.

According to an embodiment of the present disclosure, the metal complex has a general formula of Ir(L_a)₃, Ir(L_a)(L_b)₂, Ir(L_a)₂(L_b), Ir(L_a)(L_c)₂, Ir(L_a)₂(L_c) or Ir(L_a)(L_b)(L_c), wherein L_ais, at each occurrence identically or differently, selected from the group consisting of L_a1to L_a821, L_bis, at each occurrence identically or differently, selected from the group consisting of L_b1to L_b334, and the ligand L_cis, at each occurrence identically or differently, selected from the group consisting of L_c1to L_c360.

According to an embodiment of the present disclosure, the metal complex is selected from the group consisting of Metal Complex 1 to Metal Complex 432, wherein the specific structures of Metal Complex 1 to Metal Complex 432 are referred to claim 18.

According to an embodiment of the present disclosure, hydrogens in Metal Complex 1 to Metal Complex 432 can be partially or fully deuterated.

According to an embodiment of the present disclosure, the metal complex is selected from the group consisting of Metal Complex 1 to Metal Complex 435, wherein the specific structures of Metal Complex 1 to Metal Complex 435 are referred to claim 18.

According to an embodiment of the present disclosure, hydrogens in Metal Complex 1 to Metal Complex 435 can be partially or fully deuterated.

According to an embodiment of the present disclosure, disclosed is an organic electroluminescent device comprising an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein at least one layer of the organic layer comprises the metal complex in any one of the preceding embodiments.

According to an embodiment of the present disclosure, the organic layer comprising the metal complex is a light-emitting layer.

According to an embodiment of the present disclosure, the organic electroluminescent device emits green light.

According to an embodiment of the present disclosure, the organic electroluminescent device emits yellow light.

According to an embodiment of the present disclosure, the light-emitting layer further comprises a first host compound.

According to an embodiment of the present disclosure, the light-emitting layer further comprises a second host compound.

According to an embodiment of the present disclosure, at least one of the host compound comprises at least one chemical group selected from the group consisting of: benzene, pyridine, pyrimidine, triazine, carbazole, azacarbazole, indolocarbazole, dibenzothiophene, aza-dibenzothiophene, dibenzofuran, azadibenzofuran, dibenzoselenophene, triphenylene, azatriphenylene, fluorene, silafluorene, naphthalene, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene, azaphenanthrene and combinations thereof.

According to an embodiment of the present disclosure, the metal complex is doped in the first host compound and the second host compound, and the weight of the metal complex accounts for 1% to 30% of the total weight of the light-emitting layer.

According to an embodiment of the present disclosure, the metal complex is doped in the first host compound and the second host compound, and the weight of the metal complex accounts for 3% to 13% of the total weight of the light-emitting layer.

According to an embodiment of the present disclosure, disclosed is a compound composition comprising the metal complex in any one of the preceding embodiments.

Combination with Other Materials

The materials described in the present disclosure for a particular layer in an organic light-emitting device can be used in combination with various other materials present in the device. The combinations of these materials are described in more detail in U.S. Pat. App. No. 20160359122 at paragraphs 0132-0161, which is incorporated by reference herein in its entirety. The materials described or referred to the disclosure 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.

The materials described herein as useful for a particular layer in an organic light-emitting device may be used in combination with a variety of other materials present in the device. For example, dopants disclosed herein may be used in combination with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes and other layers that may be present. The combination of these materials is described in detail in paragraphs 0080-0101 of U.S. Pat. App. No. 20150349273, which is incorporated by reference herein in its entirety. The materials described or referred to the disclosure 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.

In the embodiments of material synthesis, all reactions were performed under nitrogen protection unless otherwise stated. All reaction solvents were anhydrous and used as received from commercial sources. Synthetic products were structurally confirmed and tested for properties using one or more conventional equipment in the art (including, but not limited to, nuclear magnetic resonance instrument produced by BRUKER, liquid chromatograph produced by SHIMADZU, liquid chromatograph-mass spectrometry produced by SHIMADZU, gas chromatograph-mass spectrometry produced by SHIMADZU, differential Scanning calorimeters produced by SHIMADZU, fluorescence spectrophotometer produced by SHANGHAI LENGGUANG TECH., electrochemical workstation produced by WUHAN CORRTEST, and sublimation apparatus produced by ANHUI BEQ, etc.) by methods well known to the persons skilled in the art. In the embodiments of the device, the characteristics of the device were also tested using conventional equipment in the art (including, but not limited to, evaporator produced by ANGSTROM ENGINEERING, optical testing system produced by SUZHOU FATAR, life testing system produced by SUZHOU FATAR, and ellipsometer produced by BEIJING ELLITOP, etc.) by methods well known to the persons skilled in the art. As the persons skilled in the art are aware of the above-mentioned equipment use, test methods and other related contents, the inherent data of the sample can be obtained with certainty and without influence, so the above related contents are not further described in this patent.

Material Synthesis Example

The method for preparing a compound in the present disclosure is not limited herein. Typically, the following compounds are used as examples without limitation, and synthesis routes and preparation methods thereof are described below.

Synthesis Example 1: Synthesis of Metal Complex 159

Step 1:

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In a dry 250 mL round-bottom flask, 6-chloro-dibenzofuran-3-carbonitrile (3.4 g, 13.9 mmol), B₂pin₂(4.1 g, 16.0 mmol), Pd(OAc)₂(0.09 g, 0.4 mmol), Xphos (0.4 g, 0.8 mmol), KOAc (2.0 g, 21.0 mmol) and dioxane (90 mL) were added in sequence and heated to reflux for 12 h under N₂protection.

The above-obtained reaction solution was cooled and added with 2-bromo-4-fluoro-pyridine (2.9 g, 16.7 mmol), Pd(dppf)Cl₂(0.5 g, 0.7 mmol), K₂CO₃(2.9 g, 16.7 mmol) and water (30 mL). The reaction solution was heated to reflux for 12 h under N₂protection. The reaction solution was cooled, extracted with DCM, and subjected to column chromatography to obtain Intermediate 1 (3.3 g, 82.5%).

Step 2:

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In a dry 250 mL round-bottom flask, Intermediate 1 (2.0 g, 6.9 mmol), carbazole (1.7 g, 10.4 mmol), potassium t-butoxide (1.4 g, 12.6 mmol) and DMF (50 mL) were added in sequence and heated to react for 12 h at 100° C. under N₂protection. The reaction was cooled, added with water and extracted with dichloromethane, the organic layer was washed twice with saturated sodium chloride, and the organic phases were collected, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified through column chromatography to obtain Intermediate 2 as a white solid (2.3 g, with a yield of 76.6%).

Step 3:

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In a dry 250 mL round-bottom flask, Intermediate 2 (1.6 g, 3.6 mmol), Intermediate 3 (2.0 g, 2.4 mmol), 2-ethoxyethanol (30 mL) and DMF (30 mL) were added in sequence and heated to react for 144 h at 95° C. under N₂protection. The reaction was cooled and filtered through Celite. The reaction was washed twice with methanol and washed twice with n-hexane. Yellow solids on the Celite were dissolved with dichloromethane. The organic phases were collected, concentrated under reduced pressure, and purified through column chromatography to obtain Metal Complex 159 as a yellow solid (0.84 g, with a yield of 33.5%). The product structure was confirmed as the target product with a molecular weight of 1047.3.

Synthesis Example 2: Synthesis of Metal Complex 169

Step 1:

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In a dry 250 mL round-bottom flask, Intermediate 4 (1.0 g, 3.3 mmol), 3,6-di-t-butylcarbazole (1.1 g, 3.9 mmol), potassium t-butoxide (0.5 g, 4.9 mmol) and DMF (50 mL) were added in sequence and heated to react for 12 h at 100° C. under N₂protection. The reaction was cooled, added with water and extracted with dichloromethane, the organic layer was washed twice with saturated sodium chloride, and the organic phases were collected, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified through column chromatography to obtain Intermediate 5 as a white solid (1.1 g, with a yield of 61.1%).

Step 2:

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In a dry 250 mL round-bottom flask, Intermediate 5 (1.1 g, 1.9 mmol), Intermediate 3 (1.3 g, 1.6 mmol), 2-ethoxyethanol (30 mL) and DMF (30 mL) were added in sequence and heated to react for 144 h at 95° C. under N₂protection. The reaction was cooled and filtered through Celite. The reaction was washed twice with methanol and washed twice with n-hexane. Yellow solids on the Celite were dissolved with dichloromethane. The organic phases were collected, concentrated under reduced pressure, and purified through column chromatography to obtain yellow Metal Complex 169 (0.45 g, with a yield of 23.9%). The product structure was confirmed as the target product with a molecular weight of 1176.5.

Synthesis Example 3: Synthesis of Metal Complex 411

Step 1:

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In a dry 250 mL round-bottom flask, Intermediate 2 (2.7 g, 6.2 mmol), Intermediate 6 (5.3 g, 5.7 mmol), 2-ethoxyethanol (50 mL) and DMF (50 mL) were added in sequence and heated to react for 144 h at 100° C. under N₂protection. The reaction was cooled and filtered through Celite. The reaction was washed twice with methanol and washed twice with n-hexane. Yellow solids on the Celite were dissolved with dichloromethane. The organic phases were collected, concentrated under reduced pressure, and purified through column chromatography to obtain Metal Complex 411 as a yellow solid (2.4 g, with a yield of 36.4%). The product structure was confirmed as the target product with a molecular weight of 1159.5.

Synthesis Example 4: Synthesis of Metal Complex 427

Step 1:

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In a dry 250 mL round-bottom flask, Intermediate 7 (2.1 g, 4.9 mmol), Intermediate 6 (3.8 g, 4.1 mmol), 2-ethoxyethanol (50 mL) and DMF (50 mL) were added in sequence and heated to react for 144 h at 100° C. under N₂protection. The reaction was cooled and filtered through Celite. The reaction was washed twice with methanol and washed twice with n-hexane. Yellow solids on the Celite were dissolved with dichloromethane. The organic phases were collected, concentrated under reduced pressure, and purified through column chromatography to obtain Metal Complex 427 as a yellow solid (2.8 g, with a yield of 59.0%). The product structure was confirmed as the target product with a molecular weight of 1152.5.

Synthesis Example 5: Synthesis of Metal Complex 433

Step 1:

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In a dry 250 mL round-bottom flask, Intermediate 8 (1.6 g, 3.6 mmol), Intermediate 3 (2.0 g, 2.4 mmol), 2-ethoxyethanol (30 mL) and DMF (30 mL) were added in sequence and heated to react for 144 h at 95° C. under N₂protection. The reaction was cooled and filtered through Celite. The reaction was washed twice with methanol and washed twice with n-hexane. Yellow solids on the Celite were dissolved with dichloromethane. The organic phases were collected, concentrated under reduced pressure, and purified through column chromatography to obtain Metal Complex 433 as a yellow solid (0.84 g, with a yield of 33.5%). The product structure was confirmed as the target product with a molecular weight of 1048.3.

Those skilled in the art will appreciate that the above preparation methods are merely exemplary. Those skilled in the art can obtain other compound structures of the present disclosure through the modifications of the preparation methods.

Device Example 1

Firstly, a glass substrate having an indium tin oxide (ITO) anode with a thickness of 80 nm was cleaned and then treated with oxygen plasma and UV ozone. After the treatment, the substrate was dried in a glovebox to remove moisture. Then, the substrate was mounted on a substrate holder and placed in a vacuum chamber. Organic layers specified below were sequentially deposited through vacuum thermal evaporation on the ITO anode at a rate of 0.2 to 2 Angstroms per second and a vacuum degree of about 10-8 torr. Compound HI was used as a hole injection layer (HIL). Compound HT was used as a hole transporting layer (HTL). Compound H1 was used as an electron blocking layer (EBL). Metal Complex 159 of the present disclosure, as a dopant, was co-deposited with Compound H1 and Compound H2 for use as an emissive layer (EML). On the EML, Compound H3 was used as a hole blocking layer (HBL). Compound ET and 8-hydroxyquinolinolato-lithium (Liq) were co-deposited for use as an electron transporting layer (ETL). Finally, 8-hydroxyquinolinolato-lithium (Liq) was deposited as an electron injection layer with a thickness of 1 nm and Al was deposited as a cathode with a thickness of 120 nm. The device was transferred back to the glovebox and encapsulated with a glass lid to complete the device.

Device Example 2

The implementation mode in Device Example 2 was the same as that in Device Example 1, except that in the emissive layer (EML), Metal Complex 159 of the present disclosure was replaced with Metal Complex 411, and the weight ratio of Compound H1, Compound H2 and Metal Complex 411 was 56:38:6.

Device Comparative Example 1

The implementation mode in Device Comparative Example 1 was the same as that in Device Example 1, except that in the emissive layer (EML), Metal Complex 159 of the present disclosure was replaced with Compound GD1.

Device Comparative Example 2

The implementation mode in Device Comparative Example 2 was the same as that in Device Example 1, except that in the emissive layer (EML), Metal Complex 159 of the present disclosure was replaced with Compound GD2.

Device Comparative Example 3

The implementation mode in Device Comparative Example 3 was the same as that in Device Example 1, except that in the emissive layer (EML), Metal Complex 159 of the present disclosure was replaced with Compound GD3.

Detailed structures and thicknesses of layers of the devices are shown in the following table. A layer using more than one material is obtained by doping different compounds at their weight ratio as recorded.

TABLE 1

Partial device structures of Device Examples 1 and 2 and Comparative Examples 1 to 3

Device ID
HL
HTL
EBL
EML
HBL
ETL

Example 1
Compound
Compound
Compound
Compound
Compound
Compound

HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Metal Complex

(40:60)

159 (47:47:6)

(350 Å)

(400 Å)

Example 2
Compound
Compound
Compound
Compound
Compound
Compound

HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Metal Complex

(40:60)

411 (56:38:6)

(350 Å)

(400 Å)

Comparative
Compound
Compound
Compound
Compound
Compound
Compound

Example 1
HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Compound GD1

(40:60)

(47:47:6)

(350 Å)

(400 Å)

Comparative
Compound
Compound
Compound
Compound
Compound
Compound

Example 2
HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Compound GD2

(40:60)

(47:47:6)

(350 Å)

(400 Å)

Comparative
Compound
Compound
Compound
Compound
Compound
Compound

Example 3
HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Compound GD3

(40:60)

(47:47:6)

(350 Å)

(400 Å)

The materials used in the devices have the following structures:

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The current-voltage-luminance (IVL) characteristics of the devices were measured. Under 1000 cd/m², the CIE data, maximum emission wavelength (λ_max), full width at half maximum (FWHM), driving voltage (V), current efficiency (CE) and external quantum efficiency (EQE) of the devices were measured. Lifetime (LT97) data was tested at a constant current of 80 mA/cm². The data was recorded and shown in Table 2.

TABLE 2

Device data of Device Examples 1 and 2 and Comparative Examples 1 to 3

λ_max
FWHM
Voltage
CE
EQE
LT 97

Device ID
CIE (x, y)
(nm)
(nm)
(V)
(cd/A)
(%)
(h)

Example 1
(0.406, 0.584)
544
58.7
2.55
103
27.39
62.5

Example 2
(0.428, 0.564)
547
62.7
2.69
98
26.60
67.2

Comparative
(0.429, 0.564)
546
53.7
2.56
90
24.57
59.0

Example 1

Comparative
(0.351, 0.627)
531
50.7
2.60
95
24.52
52.3

Example 2

Comparative
(0.444, 0.549)
550
70.6
2.57
88
25.29
51.3

Example 3

Discussion

Table 2 shows the device performance of the metal complexes of the present disclosure and the comparative compounds. Metal Complex 159 of the present disclosure differs from Comparative Compound GD1 only in that the carbazole substituent is located at different substitution positions of pyridine in the ligand L_a. Compared with Comparative Example 1, Example 1 has substantially the same driving voltage, the CE increased by 14.4%, the EQE increased by 11.4%, and the lifetime increased by 5.9%, indicating that the metal complex of the present application comprising a ligand L_awith the substituent R_nat the particular position can improve the device efficiency (CE and EQE) and the lifetime and significantly improve the overall performance of the device.

Metal Complex 159 of the present disclosure differs from Comparative Compound GD2 only in that a carbazole substitution exists at position 4 of pyridine in the ligand L_a. Compared with Comparative Example 2, Example 1 has the slightly reduced driving voltage, the CE increased by 8.4%, the EQE increased by 11.7%, and the lifetime increased by 19.5%, indicating that the metal complex of the present application comprising the ligand L_awith the substituent R_nat the particular position can improve the device efficiency (CE and EQE) and the lifetime and significantly improve the overall performance of the device.

Metal Complex 159 of the present disclosure differs from Comparative Compound GD3 only in that a carbazole substituent, rather than phenyl, exists at position 4 of pyridine in the ligand L_a. Compared with Comparative Example 3, Example 1 has substantially the same driving voltage, the CE increased by 17.0%, the EQE increased by 8.3%, and the lifetime increased by 21.8%, indicating that the metal complex of the present application comprising the ligand L_awith the substituent R_nat the particular position can improve the device efficiency (CE and EQE) and the lifetime and significantly improve the overall performance of the device.

In addition, the maximum emission wavelength of the device in Example 1 is in the region close to yellow light, and the device in Example 1 has achieved the device performance including a long lifetime and high efficiency, which has a huge application prospect in the aspects of white and low blue light sources.

In Example 2, Metal Complex 411 of the present disclosure is used as a light-emitting material in the emissive layer. The voltage, CE and EQE of Example 2 maintain excellent levels comparable to those of Example 1, and the lifetime of Example 2 is further improved. Meanwhile, the EQE and lifetime of Example 2 are significantly improved compared with those of Comparative Examples 1 to 3. Therefore, Example 2 has excellent light emission performance and an excellent device lifetime.

All the above results indicate that the metal complex of the present disclosure comprising the ligand L_awith the substituent R_nat the particular position, when applied to an organic electroluminescent device, can improve the device efficiency (CE and EQE) and the lifetime and achieve the beneficial effect of significantly improving the overall performance of the device.

Device Example 3

The implementation mode in Device Example 3 was the same as that in Device Example 2, except that in the emissive layer (EML), Metal Complex 411 of the present disclosure was replaced with Metal Complex 427.

Device Example 4

The implementation mode in Device Example 4 was the same as that in Device Example 2, except that in the emissive layer (EML), Metal Complex 411 of the present disclosure was replaced with Metal Complex 433.

Detailed structures and thicknesses of layers of the devices are shown in Table 3. A layer using more than one material is obtained by doping different compounds at their weight ratio as recorded.

TABLE 3

Device structures of Device Examples 3 and 4

Device ID
HL
HTL
EBL
EML
HBL
ETL

Example 3
Compound
Compound
Compound
Compound
Compound
Compound

HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Metal Complex

(40:60)

427 (56:38:6)

(350 Å)

(400 Å)

Example 4
Compound
Compound
Compound
Compound
Compound
Compound

HI (100 Å)
HT (350 Å)
H1 (50 Å)
H1:Compound
H3 (50 Å)
ET:Liq

H2:Metal Complex

(40:60)

433 (56:38:6)

(350 Å)

(400 Å)

The new materials used in the devices have the following structures:

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The IVL characteristics of the devices were measured. Under 1000 cd/m², the CIE data, maximum emission wavelength (λ_max), full width at half maximum (FWHM), driving voltage (V), current efficiency (CE) and external quantum efficiency (EQE) of the devices were measured. The data was recorded and shown in Table 4.

TABLE 4

Device data of Device Examples 3 and 4

λ_max
FWHM
Voltage
CE
EQE

Device ID
CIE (x, y)
(nm)
(nm)
(V)
(cd/A)
(%)

Example 3
(0.433, 0.559)
550
66.6
2.83
96
26.40

Example 4
(0.373, 0.671)
536
54.5
2.60
107
27.72

Discussion:

Table 4 further shows the device performance of the metal complexes of the present disclosure. In Example 3 and Example 4, Metal Complex 427 and Metal Complex 433 of the present disclosure comprising the ligand L_awith the substituent R_nat the particular position are used as the light-emitting material in the emissive layer, respectively. The voltages, CE and EQE of Example 3 and Example 4 remain comparable to those of Example 1. Meanwhile, the EQE of Example 3 and the EQE of Example 4 are significantly improved compared with those of Comparative Examples 1 to 3.

All the above results indicate that the metal complexes of the present disclosure comprising ligands L_awith different substituents R_nat a particular position and different ligands L_b, when applied to organic electroluminescent devices, can improve the device efficiency (CE and EQE) and/or the lifetime and achieve the beneficial effect of significantly improving the overall performance of the devices.

It is to be understood that various embodiments described herein are merely examples and not intended to limit the scope of the present disclosure. Therefore, it is apparent to the persons skilled in the art that the present disclosure as claimed may include variations of specific embodiments and preferred embodiments described herein. Many of materials and structures described herein may be substituted with other materials and structures without departing from the spirit of the present disclosure. It is to be understood that various theories as to why the present disclosure works are not intended to be limitative.

Number	Date	Country	Kind
202210078763.2	Jan 2022	CN	national
202211472133.X	Nov 2022	CN	national

ORGANIC ELECTROLUMINESCENT MATERIAL AND DEVICE THEREOF

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