Organic light-emitting device and display device

Abstract

Disclosed are an organic electroluminescent device and a display device. The organic light-emitting device comprises an anode, a cathode and a light-emitting layer arranged between the anode and the cathode, wherein the light-emitting layer comprises a metal complex with a structural ligand as shown in a formula 1 and a thermally activated delayed fluorescent material. The organic light-emitting device shows excellent comprehensive device performance, such as low driving voltage, high efficiency and long service life. The invention also discloses a display device comprising the organic electroluminescent device, and a composition comprising a metal complex having a structural ligand of formula 1 and a thermally activated delayed fluorescent material.

Description

TECHNICAL FIELD

[0001] The present application relates to organic electronic devices, such as organic electroluminescent devices. More particularly, it relates to an organic electroluminescent device comprising a metal complex and a thermally activated delayed fluorescence material in a light-emitting layer and a display device comprising the same, and a composition comprising a metal complex and a thermally activated delayed fluorescence material. BACKGROUND

[0002] Organic electronic devices include, but are not limited to, the following kinds: 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 electroluminescent devices.

[0003] In 1987, Tang and Van Slyke at Kodak reported a two-layer organic electroluminescent device that included an arylamine hole-transport layer and a tris-8-hydroxyquinoline-aluminum layer as the electron-transport and light-emitting layers (Applied Physics Letters, 1987, 51(12): 913-915). Upon biasing the device, green light emitted from the device. This invention laid the foundation for the development of modern organic light emitting diodes (OLEDs). State-of-the-art OLEDs can include multiple layers, such as charge injection and transport layers, charge and exciton blocking layers, and one or more light emitting layers between the cathode and anode. Since OLEDs are self-emissive solid state devices, they offer tremendous potential for display and lighting applications. In addition, the inherent properties of organic materials, such as their flexibility, can make them well suited for special applications, such as fabrication on flexible substrates.

[0004] OLEDs can be categorized into three different types according to their light emission mechanism. OLEDs invented by Tang and van Slyke are fluorescent OLEDs. It only uses singlet emission. The triplet states generated in the device are wasted by a non-emissive decay channel. Therefore, the internal quantum efficiency (IQE) of fluorescent OLEDs is only 25%. This limitation hinders the commercialization of OLEDs. In 1997, Forrest and Thompson reported phosphorescent OLEDs, which use triplet emission from heavy metals containing complexes as emitters. Therefore, both singlet and triplet states can be harvested, achieving 100% IQE. Due to its high efficiency, the discovery and development of phosphorescent OLEDs have directly contributed to the commercialization of active-matrix OLEDs (AMOLEDs). Recently, Adachi achieved high efficiency through thermally activated delayed fluorescence (TADF) of organic compounds. These emitters have small singlet-triplet gaps, making it possible for excitons to return from triplet to singlet states. In TADF devices, triplet excitons can generate singlet excitons through reverse intersystem crossing, resulting in high IQE.

[0005] OLEDs can also be categorized into small molecule and polymer OLEDs according to the form of materials used. Small molecules refer to any organic or organometallic materials that are not polymers. The molecular weight of small molecules can be quite large as long as they have precise structures. Dendrimers with well-defined structures are considered small molecules. Polymer OLEDs include conjugated polymers and non-conjugated polymers with side groups of light emitting groups. Small molecule OLEDs can become polymer OLEDs if post polymerization occurs during the manufacturing process.

[0006] There are various OLED manufacturing methods. Small molecule OLEDs are usually manufactured by vacuum thermal evaporation. Polymer OLEDs are manufactured by solution methods, such as spin coating, inkjet printing and nozzle printing. Small molecule OLEDs can also be manufactured by solution methods if the materials can be dissolved or dispersed in solvents.

[0007] The emission color of OLEDs can be achieved by the structure design of light emitting materials. OLEDs can include one light emitting layer or multiple light emitting layers to achieve the desired spectrum. Green, yellow and red OLEDs, phosphorescent materials have been successfully commercialized. Blue phosphorescent devices still have problems of blue unsaturation, short device lifetime and high operating voltage. Commercial full-color OLED displays usually use a hybrid strategy, using blue fluorescent and phosphorescent yellow, or red and green. Currently, the rapid decrease in efficiency of phosphorescent OLEDs at high brightness is still a problem. In addition, it is desirable to have more saturated emission spectrum, higher efficiency and longer device lifetime.

[0008] The performance of current TADF devices still needs to be improved, such as voltage, device efficiency and lifetime, etc., so such devices are worth further research and development. SUMMARY

[0009] The present application aims to provide a novel organic electroluminescent device to solve at least part of the above problems. The organic electroluminescent device comprises a metal complex having a ligand with structure of Formula 1 and a thermally activated delayed fluorescence material in the light-emitting layer. This novel organic electroluminescent device can exhibit excellent comprehensive device performance, such as low driving voltage, high efficiency and long lifetime, etc.

[0010] According to one embodiment of the present application, an organic electroluminescent device is disclosed, comprising:

[0011] an anode,

[0012] a cathode,

[0013] and a light-emitting layer disposed between the anode and the cathode, the light-emitting layer comprising at least a metal complex and a thermally activated delayed fluorescence material;

[0014] the metal complex comprising a metal M and a ligand L coordinated to the metal M a , the L a having a structure represented by Formula 1:

[0015]

[0016] wherein,

[0017] ring C y is selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof;

[0018] ring C x is selected from an unsaturated fused ring having 10-30 ring atoms;

[0019] G1and G2are the same or different at each occurrence and are selected from a single bond, O or S;

[0020] R x represents mono- or poly-substitution at each occurrence;

[0021] R y represents mono-, poly- or no substitution at each occurrence;

[0022] R x and R yeach occurrence is the same or different selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilicon with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxyl, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0023] at least one R x selected from cyano or fluorine;

[0024] adjacent substituents R x , R y may optionally be linked to form a ring.

[0025] According to another embodiment of the present application, a display device comprising the organic electroluminescent device as described above is also disclosed.

[0026] The present application aims to provide a novel organic electroluminescent device to solve at least part of the above problems. The organic electroluminescent device comprises a metal complex having a ligand with structure of Formula 1 and a thermally activated delayed fluorescence material in the light-emitting layer. This novel organic electroluminescent device can exhibit excellent comprehensive device performance, such as low driving voltage, high efficiency and long lifetime, etc. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of an organic light emitting device that can contain the compositions disclosed herein.

[0028] Figure 2 is another schematic diagram of an organic light emitting device that can contain the compositions disclosed herein. DETAILED DESCRIPTION

[0029] OLEDs can be manufactured on a variety of substrates, such as glass, plastic, and metal. Figure 1An organic light emitting device 100 is schematically, non-limitingly illustrated. The figures are not necessarily drawn to scale and some layer structures in the figures can also be omitted as desired. The device 100 can include a substrate 101, an anode 110, a hole injection layer 120, a hole transport layer 130, an electron blocking layer 140, a light emitting layer 150, a hole blocking layer 160, an electron transport layer 170, an electron injection layer 180, and a cathode 190. The device 100 can be fabricated by sequentially depositing the described layers. The properties and functions of the various layers, as well as exemplary materials, are described in more detail in U.S. Patent No. 7,279,704 B2, columns 6-10, the entire contents of which are incorporated by reference.

[0030] There are many more examples of each of these layers. For example, flexible and transparent substrate-anode combinations are disclosed in U.S. Patent No. 5,844,363, incorporated by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ in a 50:1 molar ratio, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, incorporated by reference in its entirety. Examples of host materials are disclosed in U.S. Patent No. 6,303,238, issued to Thompson et al., incorporated by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li in a 1:1 molar ratio, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, incorporated by reference in its entirety. U.S. Patent Nos. 5,703,436 and 5,707,745, incorporated by reference in their entirety, disclose examples of cathodes, including composite cathodes with a thin layer of metal, such as Mg:Ag, overlying a transparent, conductive, sputter-deposited ITO layer. The principles and use of blocking layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, incorporated by reference in their entirety. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004 / 0174116, incorporated by reference in its entirety. Descriptions of protective layers can be found in U.S. Patent Application Publication No. 2004 / 0174116, incorporated by reference in its entirety.

[0031] The layered structure described above is provided by way of non-limiting example. The function of the OLED can be achieved by combining various layers described above, or some layers can be omitted entirely. It can also include other layers not explicitly described. Within each layer, a single material or a mixture of materials can be used to achieve optimal performance. Any functional layer can include several sub-layers. For example, the light emitting layer can have two layers of different light emitting materials to achieve a desired light emission spectrum.

[0032] In one embodiment, an OLED can be described as having a "organic layer" disposed between a cathode and an anode. This organic layer can comprise one or more layers.

[0033] OLEDs also require an encapsulating layer, such as Figure 2 An illustrative, non-limiting, organic light emitting device 200 is shown with Figure 1 Instead, the cathode 190 can also include an encapsulating layer 102 over the cathode 190 to prevent harmful materials from the environment, such as moisture and oxygen. Any material capable of providing an encapsulating function can be used as the encapsulating layer, such as glass or an organic-inorganic hybrid layer. The encapsulating layer should be placed directly or indirectly on the outside of the OLED device. Multilayer thin film encapsulation is described in U.S. Patent No. 7,968,146 B2, which is incorporated by reference in its entirety.

[0034] Devices made according to embodiments of the application can be incorporated into a variety of consumer products having one or more electronic component modules (or units) of the devices. Some examples of these consumer products include flat panel displays, monitors, medical monitors, televisions, billboards, lights for indoor or outdoor illumination and / or signaling, head-up displays, fully or partially transparent displays, flexible displays, smartphones, tablet computers, phablets, wearable devices, smartwatches, laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, vehicle displays and tail lights.

[0035] The materials and structures described herein can also be used in other organic electronic devices listed previously.

[0036] As used herein, "top" means farthest from the substrate, and "bottom" means closest to the substrate. Where a first layer is described as "disposed on" a second layer, the first layer is disposed farther from the substrate than the second layer. Unless specified, there can be intervening layers between the first and second layers. For example, a cathode can be described as "disposed on" an anode even though various organic layers are between the cathode and the anode.

[0037] 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.

[0038] A ligand can be referred to as "photosensitive" when it is believed to directly contribute to the photoactive properties of the emissive material. A ligand can be referred to as "auxiliary" when it is believed not to contribute to the photoactive properties of the emissive material, but an auxiliary ligand can alter the properties of a photosensitive ligand.

[0039] It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin-statistics limit by delayed fluorescence. Delayed fluorescence can generally be divided into two types, P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence is produced by triplet-triplet annihilation (TTA).

[0040] On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the conversion between a triplet and a singlet excited state. Compounds that can produce E-type delayed fluorescence need to have a small singlet-triplet gap so that the conversion between states is possible. Thermal energy can activate the transition from triplet back to singlet. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A notable feature of TADF is that the delayed component increases with increasing temperature. If the rate of reverse intersystem crossing (RISC) is fast enough to minimize non-radiative decay from triplet, then the fraction of singlet excited states that are refilled can reach 75%. The total singlet fraction can be 100%, far exceeding the 25% spin-statistical limit for electroluminescence.

[0041] E-type delayed fluorescence characteristics can be seen in exciplex systems or in single compounds. Without being bound by theory, it is believed that E-type delayed fluorescence requires that the light-emitting material have a small singlet-triplet energy gap (ΔE S-T ). Organic non-metal containing donor-acceptor light-emitting materials can be able to achieve this. The emission of these materials is often characterized as donor-acceptor charge transfer (CT) type emission. The spatial separation of the HOMO and LUMO in these donor-acceptor type compounds often results in a small ΔE S-T . These states can include CT states. Typically, donor-acceptor light-emitting materials are constructed by linking an electron donor moiety (such as an amino or carbazole derivative) with an electron acceptor moiety (such as a N-containing six-membered aromatic ring).

[0042] Definitions of terms regarding substituents

[0043] Halogen or halide - as used herein, includes fluorine, chlorine, bromine and iodine.

[0044] Alkyl - As used herein, includes straight-chain and branched-chain alkyl groups. Alkyl groups can be alkyl groups having 1 to 20 carbon atoms, preferably alkyl groups having 1 to 12 carbon atoms, more preferably alkyl groups having 1 to 6 carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, neopentyl, 1-methylpentyl, 2-methylpentyl, 1-pentylhexyl, 1-butylpentyl, 1-heptyloctyl, 3-methylpentyl. Of the above, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-pentyl, neopentyl and n-hexyl are preferred. In addition, alkyl groups can be optionally substituted.

[0045] Cycloalkyl - As used herein includes cyclic alkyl groups. Cycloalkyl groups can be cycloalkyl groups having 3 to 20 ring carbon atoms, preferably cycloalkyl groups having 4 to 10 carbon atoms. Examples of cycloalkyl groups include cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4,4-dimethylcyclohexyl, 1-adamantyl, 2-adamantyl, 1-norbornyl, 2-norbornyl, and the like. Of the above, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4,4-dimethylcyclohexyl are preferred. In addition, cycloalkyl groups can be optionally substituted.

[0046] Heteroalkyl - As used herein, heteroalkyl groups include alkyl chains in which one or more carbons is replaced with a heteroatom selected from the group consisting of nitrogen, oxygen, sulfur, selenium, phosphorus, silicon, germanium, and boron atoms. Heteroalkyl groups can be heteroalkyl groups having 1 to 20 carbon atoms, preferably heteroalkyl groups having 1 to 10 carbon atoms, more preferably heteroalkyl groups having 1 to 6 carbon atoms. Examples of heteroalkyl groups include methoxymethyl, ethoxymethyl, ethoxyethyl, methylthiomethyl, ethylthiomethyl, ethylthioethyl, methoxymethoxy methyl, ethoxymethoxy methyl, ethoxyethoxyethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, mercaptomethyl, mercaptoethyl, mercaptopropyl, aminomethyl, aminoethyl, aminopropyl, dimethylaminomethyl, trimethylgermylmethyl, trimethylgermylethyl, trimethylgermylisopropyl, dimethylethylgermylmethyl, dimethylisopropylgermylmethyl, t-butyldimethylgermylmethyl, triethylgermylmethyl, triethylgermylethyl, triisopropylgermylmethyl, triisopropylgermylethyl, trimethylsilylmethyl, trimethylsilylethyl, trimethylsilylisopropyl, triisopropylsilylmethyl, triisopropylsilylethyl. In addition, heteroalkyl groups can be optionally substituted.

[0047] Alkenyl - As used herein, encompasses straight-chain, branched-chain, and cyclic alkenyl groups. Alkenyl groups can be alkenyl groups containing 2 to 20 carbon atoms, preferably alkenyl groups having 2 to 10 carbon atoms. Examples of alkenyl groups include ethenyl, propenyl, 1 -butenyl, 2-butenyl, 3-butenyl, 1,3-buten- dienyl, 1 -methyl-ethenyl, phenethenyl, 2,2-diphenylethenyl, 1,2-diphenylethenyl, 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 can be optionally substituted.

[0048] Alkynyl - As used herein, encompasses straight-chain alkynyl groups. Alkynyl groups can be alkynyl groups containing 2 to 20 carbon atoms, preferably alkynyl groups 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, phenylacetylenyl, phenylpropynyl, and the like. Of the above, ethynyl, propynyl, propargyl, 1 -butynyl, 2-butynyl, 3-butynyl, 1 -pentynyl, and phenylacetylenyl are preferred. Additionally, the alkynyl group can be optionally substituted.

[0049] Aryl or aromatic - As used herein, both non-fused and fused systems are contemplated. Aryl groups can be aryl groups having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, more preferably aryl groups having 6 to 12 carbon atoms. Examples of aryl groups include phenyl, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthyl, anthryl, azulenyl, phenanthryl, fluorenyl, pyrenyl, perylenyl, and azulenylenyl, preferably phenyl, biphenyl, terphenyl, triphenylene, fluorenyl, and naphthyl. Examples of non-fused 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'-methylbiphenyl, 4"-tert-butyl-p-terphenyl-4-yl, o-cumyl, m-cumyl, p-cumyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesityl, and m-quaterphenyl. Additionally, the aryl group can be optionally substituted.

[0050] ​Heterocyclyl - As used herein, non-aromatic cyclic groups are contemplated. Non-aromatic heterocyclyl groups include saturated heterocyclic groups having 3-20 ring atoms and unsaturated non-aromatic heterocyclic groups having 3-20 ring atoms, wherein at least one ring atom is selected from the group consisting of nitrogen atoms, oxygen atoms, sulfur atoms, selenium atoms, silicon atoms, phosphorus atoms, germanium atoms, and boron atoms. Preferred non-aromatic heterocyclyl groups are those having 3 to 7 ring atoms, which include at least one heteroatom such as nitrogen, oxygen, silicon, or sulfur. Examples of non-aromatic heterocyclyl groups include oxiranyl, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl, dioxolanyl, dioxanyl, aziridinyl, dihydropyrrolyl, tetrahydropyrrolyl, piperidinyl, oxazolidinyl, morpholinyl, piperazinyl, oxepanyl, thiepanyl, azepanyl, and tetrahydrothiopyranyl. Additionally, the heterocyclyl group can be optionally substituted.

[0051] Heteroaryl - As used herein, non-fused and fused heteroaromatic groups can contain 1 to 5 heteroatoms, wherein at least one heteroatom is selected from the group consisting of nitrogen atoms, oxygen atoms, sulfur atoms, selenium atoms, silicon atoms, phosphorus atoms, germanium atoms, and boron atoms. Heteroaryl also refers to heteroaromatic. Heteroaryl groups can be heteroaryl groups having 3 to 30 carbon atoms, preferably heteroaryl groups having 3 to 20 carbon atoms, more preferably heteroaryl groups having 3 to 12 carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyrrolopyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indolizine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthridine, phtalazine, pteridine, xanthene, acridine, phenoxazine, phenothiazine, benzofuro[3,2-d]pyridine, furo[3,2-d]dipyridine, thieno[3,2-d]pyridine, thieno[3,2-d]dipyridine, seleno[3,2-d]pyridine, seleno[3,2-d]dipyridine, preferably dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, triazine, benzimidazole, 1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazole, and nitrogen analogs thereof. Additionally, the heteroaryl group can be optionally substituted.

[0052] Alkoxy - as used herein, is represented by -O-alkyl, -O-cycloalkyl, -O-heteroalkyl, or -O-heterocyclyl. Examples and preferred examples of alkyl, cycloalkyl, heteroalkyl, and heterocyclyl are the same as described above. The alkoxy group can be an alkoxy group having 1 to 20 carbon atoms, preferably an alkoxy group having 1 to 6 carbon atoms. Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy, cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, tetrahydrofuranyloxy, tetrahydropyranyloxy, methoxypropyloxy, ethoxyethyloxy, methoxymethyloxy, and ethoxymethyloxy. In addition, the alkoxy group can be optionally substituted.

[0053] Aryloxy - as used herein, is represented by -O-aryl or -O-heteroaryl. Examples and preferred examples of aryl and heteroaryl are the same as described above. The aryloxy group can be an aryloxy group having 6 to 30 carbon atoms, preferably an aryloxy group having 6 to 20 carbon atoms. Examples of aryloxy groups include phenoxy and biphenyloxy. In addition, the aryloxy group can be optionally substituted.

[0054] Arylalkyl - as used herein, encompasses an aryl-substituted alkyl group. The arylalkyl group can be an arylalkyl group having 7 to 30 carbon atoms, preferably an arylalkyl group having 7 to 20 carbon atoms, more preferably an arylalkyl group having 7 to 13 carbon atoms. Examples of arylalkyl groups include benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, 2-phenylisopropyl, phenyl-t-butyl, α-naphthylmethyl, 1-α-naphthylethyl, 2-α-naphthylethyl, 1-α-naphthylisopropyl, 2-α-naphthylisopropyl, β-naphthylmethyl, 1-β-naphthylethyl, 2-β-naphthylethyl, 1-β-naphthylisopropyl, 2-β-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, benzyl, p-cyanobenzyl, m-cyanobenzyl, o-cyanobenzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, and 2-phenylisopropyl are preferred. In addition, the arylalkyl group can be optionally substituted.

[0055] Alkylsilyl groups - as used herein, encompass alkyl-substituted silyl groups. Alkylsilyl groups can be alkylsilyl groups having 3-20 carbon atoms, preferably alkylsilyl groups 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, methyldi-t-butylsilyl. Additionally, the alkylsilyl groups can be optionally substituted.

[0056] Arylsilyl groups - as used herein, encompass at least one aryl-substituted silyl group. Arylsilyl groups can be arylsilyl groups having 6-30 carbon atoms, preferably arylsilyl groups having 8 to 20 carbon atoms. Examples of arylsilyl groups include triphenylsilyl, phenyldiphenylsilyl, diphenylphenylsilyl, phenyldiethylsilyl, diphenylethylsilyl, phenyldimethylsilyl, diphenylmethylsilyl, phenyldiisopropylsilyl, diphenylisopropylsilyl, diphenylbutylsilyl, diphenylisobutylsilyl, diphenyl-t-butylsilyl. Additionally, the arylsilyl groups can be optionally substituted.

[0057] Alkylgermanyl groups - as used herein, encompass alkyl-substituted germanyl groups. Alkylgermanyl groups can be alkylgermanyl groups having 3-20 carbon atoms, preferably alkylgermanyl groups having 3 to 10 carbon atoms. Examples of alkylgermanyl groups include trimethylgermanyl, triethylgermanyl, methyldiethylgermanyl, ethyldimethylgermanyl, tripropylgermanyl, tributylgermanyl, triisopropylgermanyl, methyldiisopropylgermanyl, dimethylisopropylgermanyl, tri-t-butylgermanyl, triisobutylgermanyl, dimethyl-t-butylgermanyl, methyldi-t-butylgermanyl. Additionally, the alkylgermanyl groups can be optionally substituted.

[0058] Arylgermanyl groups - as used herein, encompass at least one aryl- or heteroaryl-substituted germanyl group. Arylgermanyl groups can be arylgermanyl groups having 6-30 carbon atoms, preferably arylgermanyl groups having 8 to 20 carbon atoms. Examples of arylgermanyl groups include triphenylgermanyl, phenyldiphenylgermanyl, diphenylphenylgermanyl, phenyldiethylgermanyl, diphenylethylgermanyl, phenyldimethylgermanyl, diphenylmethylgermanyl, phenyldiisopropylgermanyl, diphenylisopropylgermanyl, diphenylbutylgermanyl, diphenylisobutylgermanyl, diphenyl-t-butylgermanyl. Additionally, the arylgermanyl groups can be optionally substituted.

[0059] The term "aza" in aza-dibenzofurans, aza-dibenzothiophenes, and the like, refers to the replacement of one or more C-H groups in the corresponding aromatic fragment with a nitrogen atom. For example, aza-triphenylenes include dibenzo[f,h]quinoxalines, dibenzo[f,h]quinolines, and other analogs having two or more nitrogens in the ring system. Other nitrogen analogs of the aza derivatives described above will occur to those of ordinary skill in the art and all such analogs are intended to be encompassed by the terms described herein.

[0060] In the present disclosure, unless otherwise defined, when any one of the terms consisting of: substituted alkyl, substituted cycloalkyl, substituted heteroalkyl, substituted heterocyclyl, substituted aralkyl, 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, substituted carboxylic acid, substituted ester, substituted sulfinyl, substituted sulfonyl, substituted phosphine, is used, it means that any one of the alkyl, cycloalkyl, heteroalkyl, heterocyclyl, aralkyl, alkoxy, aryloxy, alkenyl, alkynyl, aryl, heteroaryl, alkylsilyl, arylsilyl, alkylgermanyl, arylgermanyl, amino, acyl, carbonyl, carboxylic acid, ester, sulfinyl, sulfonyl, and phosphine groups can be substituted with one or more selected from the group consisting of deuterium, halogen, unsubstituted alkyl having 1-20 carbon atoms, unsubstituted cycloalkyl having 3-20 ring carbon atoms, unsubstituted heteroalkyl having 1-20 carbon atoms, unsubstituted heterocyclyl having 3-20 ring atoms, unsubstituted aralkyl having 7-30 carbon atoms, unsubstituted alkoxy having 1-20 carbon atoms, unsubstituted aryloxy having 6-30 carbon atoms, unsubstituted alkenyl having 2-20 carbon atoms, unsubstituted alkynyl having 2-20 carbon atoms, unsubstituted aryl having 6-30 carbon atoms, unsubstituted heteroaryl having 3-30 carbon atoms, unsubstituted alkylsilyl having 3-20 carbon atoms, unsubstituted arylsilyl having 6-20 carbon atoms, unsubstituted alkylgermanyl having 3-20 carbon atoms, unsubstituted arylgermanyl having 6-20 carbon atoms, unsubstituted amino having 0-20 carbon atoms, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, mercapto, sulfinyl, sulfonyl, phosphine, and combinations thereof.

[0061] It should be understood that when a molecular fragment is described as a substituent or otherwise attached to another moiety, it can be written by its name according to whether it is a fragment (e.g., phenyl, phenylene, naphthyl, dibenzofuranyl) or according to whether it is an entire molecule (e.g., benzene, naphthalene, dibenzofuran). As used herein, these different ways of specifying substituents or attached fragments are considered to be equivalent.

[0062] In the compounds mentioned in the present disclosure, hydrogen atoms can be partially or completely replaced by deuterium. Other atoms such as carbon and nitrogen can also be replaced by other stable isotopes thereof. The replacement of other stable isotopes in the compounds can be preferred due to its enhanced efficiency and stability of the device.

[0063] In the compounds mentioned in the present disclosure, poly-substitution refers to di-substitution and up to the maximum available substitution. When a substituent in the compounds mentioned in the present disclosure is indicated as poly-substitution (including di-substitution, tri-substitution, tetra-substitution, etc.), it means that the substituent can exist at multiple available substitution positions on the structure to which it is connected, and the substituent that exists at multiple available substitution positions can be the same structure or different structures.

[0064] In the compounds mentioned in the present disclosure, unless explicitly defined, for example, adjacent substituents can be optionally connected to form a ring, adjacent substituents in the compounds cannot be connected to form a ring. In the compounds mentioned in the present disclosure, adjacent substituents can be optionally connected to form a ring, which includes both the case where adjacent substituents can be connected to form a ring and the case where adjacent substituents are not connected to form a ring. When adjacent substituents can be optionally connected to form a ring, the formed ring can be a single ring or a multiple ring (including a spiro ring, a bridged ring, a fused ring, etc.), and an alicyclic ring, a heteroalicyclic ring, an aromatic ring, or a heteroaromatic ring. In this expression, adjacent substituents can refer to substituents bonded to the same atom, substituents bonded to carbon atoms directly bonded to each other, or substituents bonded to further away carbon atoms. Preferably, adjacent substituents refer to substituents bonded to the same carbon atom and substituents bonded to carbon atoms directly bonded to each other.

[0065] The expression that adjacent substituents can be optionally connected to form a ring is also intended to mean that two substituents bonded to the same carbon atom are connected to each other by a chemical bond to form a ring, which can be exemplified by the following formula:

[0066]

[0067] The expression that adjacent substituents can be optionally connected to form a ring is also intended to mean that two substituents bonded to carbon atoms directly bonded to each other are connected to each other by a chemical bond to form a ring, which can be exemplified by the following formula:

[0068]

[0069] The expression that adjacent substituents can be optionally connected to form a ring is also intended to mean that two substituents bonded to further away carbon atoms are connected to each other by a chemical bond to form a ring, which can be exemplified by the following formula:

[0070]

[0071] Furthermore, the expression "adjacent substituents can optionally be joined to form a ring" is also intended to mean that, in case one of the two adjacent substituents represents hydrogen, the second substituent is bound at the position where the hydrogen atom is bound, thus forming a ring. This is exemplified by the following formula:

[0072]

[0073] According to one embodiment of the present application, an organic electroluminescent device is disclosed, comprising:

[0074] an anode,

[0075] a cathode,

[0076] and a light-emitting layer disposed between the anode and the cathode, the light-emitting layer comprising at least a metal complex and a thermally activated delayed fluorescence material (TADF material);

[0077] the metal complex comprising a metal M and a ligand L coordinated to the metal M a , the L a having a structure represented by formula 1 :

[0078]

[0079] wherein,

[0080] the ring C y is selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof;

[0081] the ring C x is selected from an unsaturated fused ring having 10-30 ring atoms;

[0082] G1and G2are the same or different at each occurrence and are selected from a single bond, O, or S;

[0083] R x represents mono- or polysubstitution at each occurrence;

[0084] R y represents mono-, polysubstitution, or no substitution at each occurrence;

[0085] R x and R yeach occurrence is selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilicon with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0086] at least one R x selected from cyano or fluorine;

[0087] adjacent substituents R x , R y may optionally be linked to form a ring.

[0088] In this context, adjacent substituents R x , R y may optionally be linked to form a ring is intended to mean that any one or more of the groups of adjacent substituents, for example, between two substituents R x , between two substituents R y , and between substituent R x and substituent R y may be linked to form a ring. Obviously, it is also possible that none of these groups of adjacent substituents are linked to form a ring.

[0089] In this context, "unsaturated condensed rings" include aromatic unsaturated condensed rings and non-aromatic unsaturated condensed rings.

[0090] According to one embodiment of the present application, wherein the ring C x comprises at least one five-membered unsaturated carbocyclic ring or five-membered unsaturated heterocyclic ring, the five-membered unsaturated heterocyclic ring comprising at least one heteroatom selected from O, S, Se, N, Si and Ge.

[0091] In this embodiment, "five-membered unsaturated carbocycle" includes five-membered aromatic unsaturated carbocycle and five-membered non-aromatic unsaturated carbocycle, and "five-membered unsaturated heterocycle" includes five-membered aromatic unsaturated heterocycle and five-membered non-aromatic unsaturated heterocycle.

[0092] According to one embodiment of the present application, wherein the metal complex has the formula M(L x is selected from fused rings comprising at least three rings.

[0093] According to one embodiment of the present application, wherein the metal complex has the formula M(L a ) m (L b ) n (L c ) q structure, wherein the ligand L a , L b and L c are respectively a first ligand, a second ligand and a third ligand coordinated to the metal M, the ligand L a , L b and L c can optionally be linked to form a polydentate ligand;

[0094] L b and L c are the same or different monanionic bidentate ligands;

[0095] m is selected from 1, 2 or 3, n is selected from 0, 1 or 2, q is selected from 0, 1 or 2, m+n+q is equal to the oxidation state of the metal M; when m is equal to or greater than 2, the plurality of L a are the same or different; when n is equal to 2, the two L b are the same or different; when q is equal to 2, the two L c are the same or different;

[0096] the ligand L a has a structure represented by formula 2:

[0097]

[0098] wherein,

[0099] the metal M is selected from a metal having a relative atomic mass greater than 40;

[0100] the ring C y is the same or different at each occurrence selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof;

[0101] G1and G2are the same or different at each occurrence selected from a single bond, O or S;

[0102] X is, on each occurrence, the same or different, selected from the group consisting of O, S, Se, NR1, CR1R1, SiR1R1, and GeR1R1;

[0103] X1-X4are, on each occurrence, the same or different, selected from C, CR x or N; and one of X1-X4is selected from C and is attached to ring C y ; one of X1-X4is also selected from C or N and is attached to G2, G2is selected from a single bond, O, or S when X1, X2, X3, or X4is selected from C, said X1, X2, X3, or X4is attached to the metal through G2, G2is selected from a single bond when X1, X2, X3, or X4is selected from N, said X1, X2, X3, or X4forms a metal-nitrogen bond with the metal through G2;

[0104] X5-X8are, on each occurrence, the same or different, selected from CR x or N;

[0105] R y is, on each occurrence, the same or different, mono-, poly-, or un-substituted;

[0106] R x , R y , and R1are, on each occurrence, the same or different, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having from 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having from 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having from 1 to 20 carbon atoms, substituted or unsubstituted heterocyclyl having from 3 to 20 ring atoms, substituted or unsubstituted aralkyl having from 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having from 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having from 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having from 2 to 20 carbon atoms, substituted or unsubstituted alkynyl having from 2 to 20 carbon atoms, substituted or unsubstituted aryl having from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, substituted or unsubstituted alkylsilicon having from 3 to 20 carbon atoms, substituted or unsubstituted arylsilicon having from 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanium having from 3 to 20 carbon atoms, substituted or unsubstituted arylgermanium having from 6 to 20 carbon atoms, substituted or unsubstituted amino having from 0 to 20 carbon atoms, acyl, carbonyl, carboxylate, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0107] at least one of X1-X8is CR x , and said R x is cyano or fluoro;

[0108] adjacent substituents Rx , R y and R1may optionally be linked to form a ring.

[0109] In the present embodiment, adjacent substituents R x , R y and R1may optionally be linked to form a ring, is intended to mean that any one or more of the following groups of adjacent substituents, namely, between two substituents R x , between two substituents R y , between two substituents R1, and between substituent R x and substituent R y , can be linked to form a ring. Obviously, it is also possible that none of these groups of adjacent substituents are linked to form a ring.

[0110] According to one embodiment of the present application, wherein said L b and L c are, on each occurrence identically or differently, selected from any of the structures represented by:

[0111]

[0112] wherein,

[0113] R a and R b , on each occurrence identically or differently, represent mono-, poly- or no substitution;

[0114] X b , on each occurrence identically or differently, is selected from the group consisting of O, S, Se, NR N1 , CR C1 R C2 ;

[0115] R a , R b , R c , R N1 , R C1 and R C2each occurrence is the same or different selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilicon with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0116] adjacent substituents R a , R b , R c , R N1 , R C1 and R C2 may optionally be linked to form a ring.

[0117] In the present embodiment, adjacent substituents R a , R b , R c , R N1 , R C1 and R C2 may optionally be linked to form a ring, is intended to mean that between groups of adjacent substituents, for example, between two substituents R a , between two substituents R b , between substituents R a and R b , between substituents R a and R c , between substituents R b and R c , between substituents R a and R N1 , between substituents R b and R N1 , between substituents R a and R C1 , between substituents R a and R C2 , between substituents R b and R C1 , between substituents R b and R C2between R C1 and R C2 , any one or more of these substituent groups can be linked to form a ring. For example, adjacent substituents R a , R b may optionally be linked to form a ring, which can form one or more of the following structures, including but not limited to: wherein W is selected from O, S, Se, NR w or CR w R w ; wherein the definitions of R w , R a , R b are the same as R a . It is obvious that these substituents can also not be linked to form a ring.

[0118] According to one embodiment of the present application, wherein G1is a single bond, the ring C y is the same or different at each occurrence, any one structure selected from the group consisting of:

[0119]

[0120] wherein,

[0121] R y is the same or different at each occurrence, mono-, poly-, or un-substituted;

[0122] R y and R y1at each occurrence, is selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilicon with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxyl, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0123] adjacent substituents R y may optionally be linked to form a ring;

[0124] wherein "#" represents the position connected to the metal M, represents the position connected to X1, X2, X3or X4.

[0125] In the present embodiment, adjacent substituents R y may optionally be linked to form a ring, is intended to mean that any two adjacent substituents R y may be linked to form a ring. Obviously, any two adjacent substituents R y may also not be linked to form a ring.

[0126] According to one embodiment of the present application, wherein the metal M is selected from the group consisting of Cu, Ag, Au, Ru, Rh, Pd, Os, Ir and Pt.

[0127] According to one embodiment of the present application, wherein the metal M is selected from Pt or Ir.

[0128] According to one embodiment of the present application, wherein the G1and G2are selected from a single bond.

[0129] According to one embodiment of the present application, wherein the metal complex has the formula Ir(L a ) m (L b ) 3-mstructures, and represented by Formula 3:

[0130]

[0131] wherein,

[0132] m is selected from 1, 2, or 3; when m is selected from 1, two L b are the same or different; when m is selected from 2 or 3, 2 or 3 L a are the same or different;

[0133] X is selected from the group consisting of O, S, Se, NR1, CR1R1, SiR1R1, and GeR1R1;

[0134] X3-X8are selected at each occurrence, identically or differently, from CR x or N;

[0135] Y1-Y4are selected at each occurrence, identically or differently, from CR y or N;

[0136] R a and R b are the same or different at each occurrence, represent mono-substitution, multi-substitution, or no substitution;

[0137] R1, R x , R y , R a , R b are the same or different at each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl having 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1-20 carbon atoms, substituted or unsubstituted heterocyclyl having 3-20 ring atoms, substituted or unsubstituted aralkyl having 7-30 carbon atoms, substituted or unsubstituted alkoxy having 1-20 carbon atoms, substituted or unsubstituted aryloxy having 6-30 carbon atoms, substituted or unsubstituted alkenyl having 2-20 carbon atoms, substituted or unsubstituted alkynyl having 2-20 carbon atoms, substituted or unsubstituted aryl having 6-30 carbon atoms, substituted or unsubstituted heteroaryl having 3-30 carbon atoms, substituted or unsubstituted alkylsilyl having 3-20 carbon atoms, substituted or unsubstituted arylsilyl having 6-20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3-20 carbon atoms, substituted or unsubstituted arylgermanyl having 6-20 carbon atoms, substituted or unsubstituted amino having 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0138] at least one of X3-X8 is CR x and said R x is cyano or fluoro;

[0139] adjacent substituents R1, R x , R y , R a and R b may optionally be linked to form a ring.

[0140] In the present embodiment, adjacent substituents R1, R x , R y , R a and R b may optionally be linked to form a ring, is intended to mean that any one or more of the following groups of adjacent substituents, for example, between two substituents R1, between two substituents R x , between two substituents R y , between two substituents R a , and between two substituents R b , can be linked to form a ring. Obviously, it is also possible that none of these groups of adjacent substituents are linked to form a ring.

[0141] According to one embodiment of the present application, wherein said X is selected from O, S or Se.

[0142] According to one embodiment of the present application, wherein said X is selected from O or S.

[0143] According to one embodiment of the present application, wherein said X is O.

[0144] According to one embodiment of the present application, wherein said m is selected from 1.

[0145] According to one embodiment of the present application, wherein at least one of X5-X8 is CR x , and said R x is cyano or fluoro.

[0146] According to one embodiment of the present application, wherein said X7 is CR x , and said R x is cyano or fluoro.

[0147] According to one embodiment of the present application, wherein said X8 is CR x , and said R x is cyano or fluoro.

[0148] According to one embodiment of the present application, wherein at least two of X1-X8 are CR x .

[0149] According to one embodiment of the present invention, at least two of the X3-X8 are CR. x .

[0150] According to one embodiment of the present invention, at least two of the X5-X8 are CR. x .

[0151] According to one embodiment of the present invention, wherein R x One of them is either cyano or fluorine, and there is at least one other R. x Or at least one R y Choose from the group consisting of: deuterium, halogens, substituted or unsubstituted alkyl groups having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 cyclic carbon atoms, substituted or unsubstituted heteroalkyl groups having 1-20 carbon atoms, substituted or unsubstituted heterocyclic groups having 3-20 cyclic atoms, substituted or unsubstituted aralkyl groups having 7-30 carbon atoms, substituted or unsubstituted alkoxy groups having 1-20 carbon atoms, substituted or unsubstituted aroxy groups having 6-30 carbon atoms, substituted or unsubstituted alkenyl groups having 2-20 carbon atoms, and substituted or unsubstituted alkenyl groups having 2-20 carbon atoms. Alkyne group, substituted or unsubstituted aryl group having 6-30 carbon atoms, substituted or unsubstituted heteroaryl group having 3-30 carbon atoms, substituted or unsubstituted alkylsilyl group having 3-20 carbon atoms, substituted or unsubstituted arylsilyl group having 6-20 carbon atoms, substituted or unsubstituted alkylgermanium group having 3-20 carbon atoms, substituted or unsubstituted arylgermanium group having 6-20 carbon atoms, substituted or unsubstituted amino group, acyl group, carbonyl group, carboxylic acid group, ester group, cyano group, isocyano group, hydroxyl group, mercapto group, sulfinyl group, sulfonyl group, phosphin group, and combinations thereof having 0-20 carbon atoms.

[0152] According to one embodiment of the present invention, wherein R x One of them is either cyano or fluorine, and there is at least one other R. x Or at least one R y The group consisting of: deuterium, halogens, substituted or unsubstituted alkyl groups having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6-30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3-30 carbon atoms, substituted or unsubstituted alksilyl groups having 3-20 carbon atoms, substituted or unsubstituted arylsilyl groups having 6-20 carbon atoms, substituted or unsubstituted amino, cyano, hydroxyl, mercapto groups having 0-20 carbon atoms, and combinations thereof.

[0153] According to one embodiment of the present invention, wherein R x One of them is either cyano or fluorine, and there is at least one other R.x Choose from the group consisting of: deuterium, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 30 carbon atoms, and combinations thereof.

[0154] According to one embodiment of the present invention, wherein R x One of them is either cyano or fluorine, and there is at least one other R. x It is selected from the group consisting of: substituted or unsubstituted aryl groups having 6-15 carbon atoms, substituted or unsubstituted heteroaryl groups having 3-15 carbon atoms, and combinations thereof.

[0155] According to one embodiment of the present invention, wherein R y At least one of them is selected from the group consisting of: deuterium, fluorine, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 30 carbon atoms, and combinations thereof.

[0156] According to one embodiment of the present invention, at least two of the X5-X8 are CR. x And at least one of the R x It is either cyano or fluorine, and at least one of the R groups. x Choose from the group consisting of: deuterium, halogens, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 30 carbon atoms, and combinations thereof.

[0157] According to one embodiment of the present invention, wherein X7 is CR x And the R x It is either cyano or fluorine, X8 is CR x And the R x Choose from the group consisting of: deuterium, halogens, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 30 carbon atoms, and combinations thereof.

[0158] According to one embodiment of the present invention, wherein X7 is CR x And the R x It is either cyano or fluorine, X8 is CR x And the Rx selected from the group consisting of deuterium, substituted or unsubstituted aryl having 6-30 carbon atoms, substituted or unsubstituted heteroaryl having 3-30 carbon atoms, and combinations thereof.

[0159] According to one embodiment of the present application, wherein Y1-Y4are each independently selected from CR y , the R y is selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl having 3-20 ring carbon atoms, substituted or unsubstituted aryl having 6-30 carbon atoms, substituted or unsubstituted heteroaryl having 3-30 carbon atoms, substituted or unsubstituted alkylsilicon having 3-20 carbon atoms, substituted or unsubstituted arylsilicon having 6-20 carbon atoms, substituted or unsubstituted amino having 0-20 carbon atoms, cyano, hydroxyl, thiol, and combinations thereof.

[0160] According to one embodiment of the present application, wherein Y1-Y4are each independently selected from CR y , the R y is selected from the group consisting of hydrogen, deuterium, fluorine, substituted or unsubstituted alkyl having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl having 3-20 ring carbon atoms, substituted or unsubstituted aryl having 6-30 carbon atoms, substituted or unsubstituted heteroaryl having 3-30 carbon atoms, and combinations thereof.

[0161] According to one embodiment of the present application, wherein L a is selected from the group consisting of L a1 to L a555 , the specific structures of L a1 to L a555 are found in claim 9.

[0162] According to one embodiment of the present application, wherein hydrogen in L a1 to L a555 may be partially or completely substituted with deuterium.

[0163] According to one embodiment of the present application, wherein L b is selected from the group consisting of L b1 to L b160 , the specific structures of L b1 to L b160 are found in claim 9.

[0164] According to one embodiment of the present application, wherein L b1 to L b18 , L b20 to L b26 , and Lb31 to L b160 may be partially or completely substituted with deuterium.

[0165] According to one embodiment of the present application, wherein said L c is selected from the group consisting of L c1 to L c50 , said L c1 to L c50 The specific structure of L

[0166] According to one embodiment of the present application, wherein said L c1 to L c50 may be partially or completely substituted with deuterium.

[0167] According to one embodiment of the present application, wherein said metal complex has the structure of Ir(L a )(L b )2, wherein two L b are the same or different; L a is selected from the group consisting of L a1 to L a555 at each occurrence is the same or different selected from the group consisting of L b to L b1 at each occurrence is the same or different selected from the group consisting of L b160 to L

[0168] According to one embodiment of the present application, wherein said metal complex is selected from the group consisting of metal complex 1 to metal complex 614, the specific structure of metal complex 1 to metal complex 614 is shown in claim 10.

[0169] According to one embodiment of the present application, wherein the maximum emission wavelength in the photoluminescence spectrum of said metal complex is 500 nm ~ 580 nm.

[0170] According to one embodiment of the present application, wherein the maximum emission wavelength in the photoluminescence spectrum of said metal complex is 500 nm ~ 560 nm.

[0171] According to one embodiment of the present application, wherein the full width at half maximum in the photoluminescence spectrum of said metal complex is less than 80 nm.

[0172] According to one embodiment of the present application, wherein the full width at half maximum in the photoluminescence spectrum of said metal complex is less than 60 nm.

[0173] According to one embodiment of the present application, wherein the full width at half maximum in the photoluminescence spectrum of said metal complex is less than 50 nm.

[0174] According to one embodiment of the present application, wherein the full width at half maximum in the photoluminescence spectrum of the metal complex is less than 40 nm.

[0175] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material comprises at least one substituted or unsubstituted carbazole structure.

[0176] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material comprises at least two substituted or unsubstituted carbazole structures.

[0177] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material comprises at least one substituted or unsubstituted diarylamino structure.

[0178] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material comprises at least two substituted or unsubstituted diarylamino structures.

[0179] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material comprises at least one substituted or unsubstituted carbazole group and at least one substituted or unsubstituted diarylamino structure.

[0180] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material structure has a structure represented by Formula 4:

[0181]

[0182] wherein,

[0183] each of ring A, ring B, ring C, ring D, ring E is independently selected from an unsaturated carbocyclic ring having 5-30 carbon atoms or an unsaturated heterocyclic ring having 3-30 carbon atoms;

[0184] each of Z1, E1and E2is independently selected from B, N, P, P=O, P=S, As, As=O, As=S, SiR Si1 or GeR Ge1 ;

[0185] each of T1to T8is independently selected from C, CR’ or N;

[0186] each of a, b, c, d is independently selected from 0 and 1;

[0187] each occurrence of L1, L2, L3, L4is the same or different selected from a single bond, O, S, Se, BR or NR;

[0188] each occurrence of R’ represents mono-, poly- or no substitution;

[0189] R, R’, R Si1 and R Ge1each occurrence is selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, -BR”R”, and combinations thereof;

[0190] each occurrence is selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0191] adjacent substituents R, R’, R”, R Si1 and R Ge1 may optionally be linked to form a ring.

[0192] In this embodiment, "a, b, c, d are each independently selected from 0 or 1" is intended to mean that a, b, c, d correspondingly connect or disconnect between T1 and T2, T3 and T4, T5 and T6, T7 and T8. For example: when a is 0, T1 and T2 are disconnected (i.e. T1 and T2 are not connected); the same is true when one or more of a, b, c, d is 0.

[0193] In this context, adjacent substituents R, R', R", R Si1 and R Ge1 may optionally be connected to form a ring, is intended to mean that any one or more of these adjacent groups of substituents, for example between two substituents R', between two substituents R", between a substituent R' and a substituent R Si1 , and between a substituent R' and a substituent R" Ge1 , can be connected to form a ring. Obviously, it is also possible that none of these adjacent groups of substituents is connected to form a ring.

[0194] In this context, "carbocyclic" includes saturated carbocyclic and unsaturated carbocyclic, "unsaturated carbocyclic" includes aromatic unsaturated carbocyclic and non-aromatic unsaturated carbocyclic, "heterocyclic" includes saturated heterocyclic and unsaturated heterocyclic, "unsaturated heterocyclic" includes aromatic unsaturated heterocyclic and non-aromatic unsaturated heterocyclic.

[0195] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material structure has a structure represented by formula 4-1:

[0196]

[0197] wherein,

[0198] ring A, ring B, ring C, ring D, ring E are each independently selected from an unsaturated carbocyclic having 5-30 carbon atoms or an unsaturated heterocyclic having 3-30 carbon atoms;

[0199] Z1, E1and E2are each independently selected from B, N, P, P=O, P=S, As, As=O, As=S, SiR Si1 or GeR Ge1 ;

[0200] T7and T8are each independently selected from C, CR' or N;

[0201] d is selected from 0 and 1;

[0202] L4is selected, identically or differently on each occurrence, from a single bond, O, S, Se, BR or NR;

[0203] R' represents, on each occurrence, identically or differently, mono-, poly- or non-substitution;

[0204] R, R', R Si1 and R Ge1 each occurrence is the same or different, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, -BR”R”, and combinations thereof;

[0205] R” each occurrence is the same or different, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0206] adjacent substituents R, R', R”, R Si1 and RGe1 optionally linked to form a ring.

[0207] According to one embodiment of the present application, wherein said ring A, ring B, ring C, ring D and ring E are each, the same or different at each occurrence, selected from a five-membered unsaturated carbocyclic ring, an aromatic ring having 6-30 carbon atoms or a heteroaromatic ring having 3-30 carbon atoms.

[0208] According to one embodiment of the present application, wherein said ring A, ring B, ring C, ring D and ring E are each, the same or different at each occurrence, selected from a five-membered unsaturated carbocyclic ring, an aromatic ring having 6-18 carbon atoms or a heteroaromatic ring having 3-18 carbon atoms.

[0209] According to one embodiment of the present application, wherein said ring A, ring B, ring C, ring D and ring E are each, the same or different at each occurrence, selected from a benzene ring, a pyridine ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, an indene ring, a fluorene ring, an indole ring, a carbazole ring, a benzofuran ring, a dibenzofuran ring, a benzothiophene ring, a dibenzothiophene ring, a dibenzoselenophene ring, a cyclopentadiene ring, a furan ring, a thiophene ring, a thiolyl ring, or a combination thereof.

[0210] According to one embodiment of the present application, wherein said ring A, ring B, ring C, ring D, ring E are selected from a benzene ring.

[0211] According to one embodiment of the present application, wherein said Z1 is selected from B, P=O or P=S, said E1 and E2 are each independently selected from N or P.

[0212] According to one embodiment of the present application, wherein said Z1 is selected from B, E1 and E2 are selected from N.

[0213] According to one embodiment of the present application, wherein said Z1 is selected from N or P, E1 and E2 are each independently selected from B, P=O or P=S.

[0214] According to one embodiment of the present application, wherein said Z1 is selected from N, E1 and E2 are selected from B.

[0215] According to one embodiment of the present application, wherein said L1, L2, L3, L4 are the same or different at each occurrence selected from a single bond, BR or NR.

[0216] According to one embodiment of the present application, wherein said a+b+c+d is greater than or equal to 1.

[0217] According to one embodiment of the present application, wherein said a+d is greater than or equal to 1.

[0218] According to one embodiment of the present application, wherein said a is 0, d is 1.

[0219] According to one embodiment of the present application, wherein a is 1 and d is 1.

[0220] According to one embodiment of the present application, wherein the thermally activated delayed fluorescence material has a structure represented by Formula 5-1 or Formula 5-2:

[0221]

[0222] wherein,

[0223] R' is the same or different at each occurrence represents mono-substituted, poly-substituted or non-substituted;

[0224] R' is the same or different at each occurrence selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl having 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1-20 carbon atoms, substituted or unsubstituted heterocyclyl having 3-20 ring atoms, substituted or unsubstituted aralkyl having 7-30 carbon atoms, substituted or unsubstituted alkoxy having 1-20 carbon atoms, substituted or unsubstituted aryloxy having 6-30 carbon atoms, substituted or unsubstituted alkenyl having 2-20 carbon atoms, substituted or unsubstituted alkynyl having 2-20 carbon atoms, substituted or unsubstituted aryl having 6-30 carbon atoms, substituted or unsubstituted heteroaryl having 3-30 carbon atoms, substituted or unsubstituted alkylsilyl having 3-20 carbon atoms, substituted or unsubstituted arylsilyl having 6-20 carbon atoms, substituted or unsubstituted alkylgermanyl having 3-20 carbon atoms, substituted or unsubstituted arylgermanyl having 6-20 carbon atoms, substituted or unsubstituted amino having 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, -BR”R”, and combinations thereof;

[0225] R" is, the same or different at each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxyl, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0226] Adjacent substituents R' and R" can optionally be joined to form a ring.

[0227] In the present embodiment, adjacent substituents R' and R" can optionally be joined to form a ring, is intended to mean that two adjacent substituents R' on the same ring can be joined to form a ring, and adjacent substituents R' and R" can optionally be joined to form a ring. Obviously, two adjacent substituents R' on the same ring can also not be joined to form a ring, and adjacent substituents R' and R" can also not be joined to form a ring.

[0228] According to one embodiment of the present application, wherein said R' is, the same or different at each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, and combinations thereof.

[0229] According to one embodiment of the present application, R' is, at each occurrence, the same or different, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having from 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having from 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, substituted or unsubstituted amino having from 0 to 20 carbon atoms, and combinations thereof.

[0230] According to one embodiment of the present application, there are multiple R' in Formula 5-1 or Formula 5-2, at least one (e.g., one, two, three, or four) of which is selected from substituted or unsubstituted alkyl having from 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having from 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, substituted or unsubstituted amino having from 0 to 20 carbon atoms, or combinations thereof.

[0231] According to one embodiment of the present application, the thermally activated delayed fluorescence material is selected from the group consisting of Compounds DF-1 to DF-95, the specific structures of which are found in Claim 21.

[0232] According to one embodiment of the present application, the hydrogen in Compounds DF-1 to DF-95 can be partially or completely substituted with deuterium.

[0233] According to one embodiment of the present application, the thermally activated delayed fluorescence material has a maximum emission wavelength in the photoluminescence spectrum of 480 nm to 580 nm.

[0234] According to one embodiment of the present application, the thermally activated delayed fluorescence material has a maximum emission wavelength in the photoluminescence spectrum of 500 nm to 560 nm.

[0235] According to one embodiment of the present application, the thermally activated delayed fluorescence material has a full width at half maximum in the photoluminescence spectrum of less than 45 nm.

[0236] According to one embodiment of the present application, the thermally activated delayed fluorescence material has a full width at half maximum in the photoluminescence spectrum of less than 40 nm.

[0237] According to one embodiment of the present application, the thermally activated delayed fluorescence material has a full width at half maximum in the photoluminescence spectrum of less than 35 nm.

[0238] According to one embodiment of the present application, the thermally activated delayed fluorescence material has a maximum emission wavelength in the photoluminescence spectrum of λ max-PL1, the maximum emission wavelength in the photoluminescence spectrum of the metal complex is λ max-PL2 , and Δλ max = λ max-PL1 - λ max-PL2 ≤ 40 nm.

[0239] According to one embodiment of the present application, wherein said Δλ max = λ max-PL1 - λ max-PL2 ≤ 30 nm.

[0240] According to one embodiment of the present application, wherein said Δλ max = λ max-PL1 - λ max-PL2 ≤ 20 nm.

[0241] According to one embodiment of the present application, wherein said Δλ max = λ max-PL1 - λ max-PL2 ≤ 10 nm.

[0242] In the present application, the maximum emission wavelength λ max-PL and the full width at half maximum FWHM- PL of the photoluminescence spectrum are tested as follows:

[0243] The photoluminescence spectrum (PL) data of the test compound is determined using a fluorescence spectrophotometer produced by Shanghai Linhong Technology Co., Ltd. with model number Linhong F98. The test compound is dissolved in toluene solvent to prepare a solution with a concentration of 1 × 10 -6 mol / L, nitrogen gas is passed through the prepared test solution for 5 minutes to remove oxygen, the test solution is loaded into a quartz sample tube, and the emission spectrum is measured at room temperature (298 K) under excitation by light with a wavelength of 400 nm. The emission spectrum has a maximum emission wavelength λ max-PL and a full width at half maximum FWHM- PL (i.e. the peak width at half the height of the maximum emission peak, by drawing a straight line parallel to the horizontal axis through the midpoint of the peak height, and the distance between the two points of intersection on both sides of the peak).

[0244] As an example, the maximum emission wavelength λ max-PL and the full width at half maximum FWHM- PL of the photoluminescence spectrum of the following metal complexes and thermally activated delayed fluorescence materials are determined by the above method, and the specific results are shown in Table 1:

[0245] Table 1 Maximum emission wavelength and full width at half maximum of the photoluminescence spectrum of the compounds

[0246] Compound No. max-PL (nm) ​ FWHM- PL (nm)]]> Metal complex 52 529 55.74 Metal complex 375 527 38.66 Metal complex 497 524 30.39 DF-81 536 34.25 .

[0247] According to one embodiment of the present application, the energy difference ΔE of the singlet energy level (S1) and the triplet energy level (T1) of the thermally activated delayed fluorescence material ST = S1 - T1 ≤ 0.40 eV.

[0248] According to one embodiment of the present application, the energy difference ΔE of the singlet energy level (S1) and the triplet energy level (T1) of the thermally activated delayed fluorescence material ST = S1 - T1 ≤ 0.30 eV.

[0249] According to one embodiment of the present application, the energy difference ΔE of the singlet energy level (S1) and the triplet energy level (T1) of the thermally activated delayed fluorescence material ST = S1 - T1 ≤ 0.20 eV.

[0250] According to one embodiment of the present application, the energy difference ΔE of the singlet energy level (S1) and the triplet energy level (T1) of the thermally activated delayed fluorescence material ST = S1 - T1 ≤ 0.10 eV.

[0251] In the present application, the test method of the singlet energy level (S1) is as follows:

[0252] A solution of 1 x 10 -6 mol / L concentration is prepared by dissolving the compound to be tested in toluene solvent, the prepared solution is deoxygenated by nitrogen for 5 minutes, and the solution is loaded into a quartz sample tube, excited by light of 400 nm wavelength at room temperature (298 K) and the emission spectrum is measured. The spectrometer used is a model F98 spectrophotometer produced by Shanghai Linhong Technology Co., Ltd.

[0253] The vertical axis of the fluorescence spectrum is the fluorescence intensity, and the horizontal axis is the wavelength. The minimum value λ1 (nm) is taken with respect to the peak on the short wavelength side of the fluorescence spectrum, and the wavelength value is brought into the following conversion formula F1 to calculate the singlet energy level (S1) of the compound to be tested.

[0254] Conversion formula F1: S1 (eV) = 1240 / λ1

[0255] In the present application, the test method of the triplet energy level (T1) is as follows:

[0256] The triplet energy level (T1) is determined under ultra-low temperature conditions using the characteristics of long-lived triplet excitons. Specifically, a solution of 1 x 10 -6mol / L concentration solution, nitrogen gas was bubbled into the prepared solution for 5 minutes to remove oxygen, the above solution was loaded into a quartz sample tube and placed in a dewar bottle and cooled to 77 K, and the solution of the compound to be measured was irradiated with a 400 nm light source to measure the phosphorescence spectrum. The spectrometer used for the measurement is a model F98 spectrophotometer produced by Shanghai Lin Guang Technology Co., Ltd.

[0257] The vertical axis of the phosphorescence spectrum is the phosphorescence intensity, and the horizontal axis is the wavelength. With respect to the peak on the short wavelength side of the phosphorescence spectrum, the minimum value λ2 (nm) is taken, and the wavelength value is brought into the conversion formula F2 below, so as to calculate the triplet energy level (T1) of the compound to be measured.

[0258] Conversion formula F2: T1 (eV) = 1240 / λ2

[0259] As an example, the singlet energy level (S1) and the triplet energy level (T1) of the following thermally activated delayed fluorescence material were measured by the above method, and the specific results are shown in Table 2:

[0260] Table 2 Singlet energy level and triplet energy level of compounds

[0261] Compound No. [S1 (eV)] [T1 (eV)] DF-81 2.313 2.300

[0262] According to Table 2, the ΔE of compound DF-81 is ST = 0.013 eV.

[0263] According to an embodiment of the present application, the light-emitting layer comprises a host material.

[0264] According to an embodiment of the present application, the host material is a host material.

[0265] According to an embodiment of the present application, the host material comprises a first host material and a second host material.

[0266] According to another embodiment of the present application, the first host material has a structure represented by formula X-1 or formula X-2:

[0267]

[0268] wherein,

[0269] L x is selected from the group consisting of a single bond, a substituted or unsubstituted alkylene having 1-20 carbon atoms, a substituted or unsubstituted cycloalkylene having 3-20 carbon atoms, a substituted or unsubstituted arylene having 6-20 carbon atoms, a substituted or unsubstituted heteroarylene having 3-20 carbon atoms, or a combination thereof, at each occurrence, identically or differently;

[0270] G is selected from the group consisting of C(Rg )2, NR g , O, or S;

[0271] V is, on each occurrence, the same or different, selected from C, CR v , or N;

[0272] In formula X-1, T is, on each occurrence, the same or different, selected from C, CR t , or N;

[0273] In formula X-2, T is, on each occurrence, the same or different, selected from CR t , or N;

[0274] R g , R v , and R t are, on each occurrence, the same or different, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having from 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having from 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having from 1 to 20 carbon atoms, substituted or unsubstituted heterocyclyl having from 3 to 20 ring atoms, substituted or unsubstituted aralkyl having from 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having from 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having from 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having from 2 to 20 carbon atoms, substituted or unsubstituted alkynyl having from 2 to 20 carbon atoms, substituted or unsubstituted aryl having from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, substituted or unsubstituted alkylsilicon having from 3 to 20 carbon atoms, substituted or unsubstituted arylsilane having from 6 to 20 carbon atoms, substituted or unsubstituted alkyl germanium having from 3 to 20 carbon atoms, substituted or unsubstituted aryl germanium having from 6 to 20 carbon atoms, substituted or unsubstituted amino having from 0 to 20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0275] Ar1is, on each occurrence, the same or different, selected from substituted or unsubstituted aryl having from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, or combinations thereof;

[0276] Adjacent substituents R g , R v , and R t may optionally be linked to form a ring.

[0277] In this embodiment, adjacent substituents R g , R v , and R t"may optionally be linked to form a ring" is intended to mean that any one or more of these groups of substituents, e.g., two substituents R v between two substituents R t between two substituents R g between substituents R v and R t between substituents R v and R g between substituents R g and R t may be linked to form a ring. It is readily apparent that none of these substituents can also be linked to form a ring.

[0278] According to one embodiment of the present application, wherein the first host material has a structure represented by one of Formula X-a to Formula X-p:

[0279]

[0280]

[0281] wherein,

[0282] L x is, at each occurrence, the same or different, selected from a single bond, substituted or unsubstituted alkylene having 1-20 carbon atoms, substituted or unsubstituted cycloalkylene having 3-20 carbon atoms, substituted or unsubstituted arylene having 6-20 carbon atoms, substituted or unsubstituted heteroarylene having 3-20 carbon atoms, or a combination thereof;

[0283] G is, at each occurrence, the same or different, selected from C(R g )2, NR g , O, or S;

[0284] V is, at each occurrence, the same or different, selected from CR v or N;

[0285] T is, at each occurrence, the same or different, selected from CR t or N;

[0286] R g , R v and R teach occurrence is the same or different selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl of 1-20 carbon atoms, substituted or unsubstituted cycloalkyl of 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl of 1-20 carbon atoms, substituted or unsubstituted heterocyclyl of 3-20 ring atoms, substituted or unsubstituted aralkyl of 7-30 carbon atoms, substituted or unsubstituted alkoxy of 1-20 carbon atoms, substituted or unsubstituted aryloxy of 6-30 carbon atoms, substituted or unsubstituted alkenyl of 2-20 carbon atoms, substituted or unsubstituted alkynyl of 2-20 carbon atoms, substituted or unsubstituted aryl of 6-30 carbon atoms, substituted or unsubstituted heteroaryl of 3-30 carbon atoms, substituted or unsubstituted alkylsilicon of 3-20 carbon atoms, substituted or unsubstituted arylsilicon of 6-20 carbon atoms, substituted or unsubstituted alkylgermanium of 3-20 carbon atoms, substituted or unsubstituted arylgermanium of 6-20 carbon atoms, substituted or unsubstituted amino of 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0287] Ar1is the same or different at each occurrence selected from substituted or unsubstituted aryl of 6-30 carbon atoms, substituted or unsubstituted heteroaryl of 3-30 carbon atoms, or combinations thereof;

[0288] adjacent substituents R g , R v and R t may optionally be linked to form a ring.

[0289] According to one embodiment of the present application, wherein the first host material is selected from the group consisting of the following compounds:

[0290]

[0291]

[0292]

[0293]

[0294]

[0295] According to another embodiment of the present application, wherein the second host material has a structure represented by the formula Y:

[0296]

[0297] wherein,

[0298] H1-H6are the same or different at each occurrence selected from C, CR h or N, and at least two of H1-H6are N, at least one of H1-H6is C, and is attached to Formula A;

[0299]

[0300] wherein,

[0301] Q is the same or different at each occurrence selected from the group consisting of O, S, Se, N, NR Q , CR Q R Q , SiR Q R Q , GeR Q R Q and R Q C=CR Q ; when two R Q are present simultaneously, the two R Q may be the same or different;

[0302] p is 0 or 1 ; r is 0 or 1 ;

[0303] when Q is selected from N, p is 0, r is 1 ;

[0304] when Q is selected from the group consisting of O, S, Se, NR Q , CR Q R Q , SiR Q R Q , GeR Q R Q and R Q C=CR Q , p is 1, r is 0;

[0305] L Q is selected from a single bond, substituted or unsubstituted alkylene having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkylene having 3 to 20 carbon atoms, substituted or unsubstituted arylene having 6 to 20 carbon atoms, substituted or unsubstituted heteroarylene having 3 to 20 carbon atoms, or a combination thereof;

[0306] Q1-Q8are the same or different at each occurrence selected from C, CR q or N;

[0307] R h , R Q and R qat each occurrence, is selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilicon with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0308] " " represents the position of attachment of Formula A to Formula Y;

[0309] adjacent substituents R h , R Q , R q may optionally be linked to form a ring.

[0310] In this context, "adjacent substituents R h , R Q , R q may optionally be linked to form a ring" is intended to mean that any one or more of these substituent groups, e.g., between two substituents R h , between two substituents R Q , between two substituents R q , between two substituents R Q and R q may be linked to form a ring. Obviously, none of these substituents can also be linked to form a ring.

[0311] According to one embodiment of the present application, wherein said second host material is selected from the group consisting of:

[0312]

[0313]

[0314]

[0315]

[0316]

[0317]

[0318]

[0319]

[0320]

[0321] According to another embodiment of the present application, a display device comprising the organic electroluminescence device according to any of the preceding embodiments is also disclosed.

[0322] According to another embodiment of the present application, a composition comprising at least a metal complex comprising a metal M and a ligand L coordinated to the metal M and a thermally activated delayed fluorescence material is also disclosed. a , said L a has a structure represented by Formula 1:

[0323]

[0324] wherein,

[0325] ring C y is selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof;

[0326] ring C x is selected from an unsaturated fused ring having 10-30 ring atoms;

[0327] G1and G2are the same or different at each occurrence and are selected from a single bond, O, or S;

[0328] R x represents, at each occurrence, the same or different, a single substitution or a multiple substitution;

[0329] R y represents, at each occurrence, the same or different, a single substitution, a multiple substitution, or no substitution;

[0330] R x and R yeach occurrence is the same or different selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof;

[0331] at least one R x selected from cyano or fluorine;

[0332] adjacent substituents R x , R y may optionally be linked to form a ring.

[0333] in combination with other materials

[0334] The materials described herein for the particular layers in an organic light emitting device can be used in combination with a variety of other materials present in the device. The combinations of these materials are described in detail in US Patent Application US2016 / 0359122A1 at paragraphs 0132-0161, which is incorporated by reference herein in its entirety. The materials described or mentioned therein are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and the skilled person can readily consult the literature to identify other materials that can be used in combination.

[0335] The materials described herein as being useful for particular layers in organic light emitting devices can be used in combination with a variety of other materials present in the devices. For example, the compounds disclosed herein can be used in conjunction with a variety of hosts, transport layers, blocking layers, injection layers, electrodes, and other layers that can be present. Combinations of these materials are described in detail in paragraphs 0080-0101 of U.S. Patent Application US2015 / 0349273A1, which is incorporated by reference herein in its entirety. The materials described or referenced therein are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that can be useful in combination.

[0336] The metal complexes and thermally activated delayed fluorescence materials used in the present application can be easily obtained by referring to the preparation methods in the prior art, for example, the metal complexes can be prepared by referring to documents such as CN111518139A, CN110903321A or CN202310859895.3, and the thermally activated delayed fluorescence materials can be prepared by referring to documents such as Adv. Funct. Mater. 2021, 2102017 (DOI: 10.1002 / adfm.202102017), and the preparation methods thereof will not be described here. The above-mentioned documents are only exemplary, and other documents can be easily obtained by those skilled in the art.

[0337] The preparation method of the electroluminescent device is not limited, and the preparation method of the following examples is only an example and should not be understood as a limitation. Those skilled in the art can reasonably improve the preparation method of the following examples according to the prior art. For example, the ratio of various materials in the light-emitting layer is not particularly limited, and those skilled in the art can reasonably select within a certain range according to the prior art, for example, based on the total weight of the light-emitting layer material, the host material can account for 75%-98%, the metal complex can account for 1%-20%, and the thermally activated delayed fluorescence material can account for 1%-5%; or the host material can account for 88%-98%, the metal complex can account for 1%-10%, and the thermally activated delayed fluorescence material can account for 1%-2%. In addition, the host material is two materials, and the ratio of the two host materials in the host material can be 99:1 to 1:99; or the ratio can be 80:20 to 20:80; or the ratio can be 70:30 to 30:70. In the examples of the device, the characteristics of the device are also tested by using the devices commonly used in the art (including but not limited to the evaporation machine produced by Angstrom Engineering, the optical test system and the life test system produced by Suzhou Fosd, the ellipsometer produced by Beijing Liangtuo, etc.), and the method familiar to those skilled in the art.

[0338] Device Examples

[0339] Device Example 1

[0340] First, a glass substrate with an 80 nm thick indium tin oxide (ITO) anode was cleaned and then treated with oxygen plasma and UV ozone. After the treatment, the substrate was dried in a glove box to remove moisture. The substrate was then mounted on a substrate holder and loaded into a vacuum chamber. The organic layers specified below were sequentially evaporated on the ITO anode by thermal vacuum evaporation at a rate of 0.2-2 Angstroms / second under a vacuum of about 10 -8 -6 Torr. Compound HT and Compound HT1 were co-evaporated as a hole injection layer (HIL). Compound HT was used as a hole transport layer (HTL). Compound PH-23 was used as an electron blocking layer (EBL). Then metal complex 52 as a phosphorescent sensitizer and TADF material Compound DF-81 doped in a first host material Compound PH-1 and a second host material Compound H-40 were co-evaporated as an emission layer (EML). On the EML, Compound HB was used as a hole blocking layer (HBL). On the HBL, Compound ET and 8-hydroxyquinoline-lithium (Liq) were co-evaporated as an electron transport layer (ETL). Finally, 1 nm thick 8-hydroxyquinoline-lithium (Liq) was evaporated as an electron injection layer, and 120 nm of aluminum was evaporated as a cathode. The device was then transferred back to the glove box and encapsulated with a glass cover and a moisture absorbent to complete the device.

[0341] Device Example 2

[0342] The implementation of Device Example 2 was the same as Device Example 1, except that metal complex 375 was used instead of metal complex 52 in the emission layer (EML).

[0343] Device Example 3

[0344] The implementation of Device Example 3 was the same as Device Example 1, except that metal complex 497 was used instead of metal complex 52 in the emission layer (EML).

[0345] Device Comparative Example 1

[0346] The implementation of Device Comparative Example 1 was the same as Device Example 1, except that TADF material Compound DF-81 doped in a first host material Compound PH-1 and a second host material Compound H-40 with a weight ratio of 59:40:1 was used in the emission layer (EML).

[0347] The detailed device layer structure and thickness are shown in the following table. The layers in which more than one material was used, were doped with different compounds in the weight ratio as indicated.

[0348] Table 3. Part of the device structure of Device Examples and Comparative Examples

[0349] Table 3. Part of the device structure of Device Examples and Comparative Examples

[0350] The material structure used in the device is shown as follows:

[0351]

[0352] The CIE data of the device was measured at a luminance of 100 cd / m 2 The maximum emission wavelength (λ max ), driving voltage (V), current efficiency (CE), power efficiency (PE), external quantum efficiency (EQE), lifetime LT97 of the device was measured and calculated at an initial luminance of 10000 cd / m 2 , which are recorded and shown in Table 4.

[0353] Device data of Examples 1-3 and Comparative Example 1

[0354]

[0355]

[0356] The difference between Examples 1-3 and Comparative Example 1 is that Examples 1-3 use metal complexes containing structural ligand L a represented by Formula 1 as phosphorescent sensitizers, while Comparative Example 1 does not use phosphorescent sensitizers. As can be seen from the data in Table 4, compared with Comparative Example 1, the maximum emission wavelength of Examples 1, 2 and 3 is consistent, the voltage is reduced by 0.32V, 0.22V and 0.17V respectively, the CE is greatly improved by 70.7%, 75.4% and 69.2% respectively, the PE is greatly improved by 95.9%, 93.2% and 82.4% respectively, the EQE is greatly improved by 70.9%, 74.3% and 66.7% respectively, and especially the lifetime is improved by 12.8 times, 11.9 times and 10 times respectively. These data show that the device of the present application has very excellent performance compared with the device without phosphorescent sensitizers, not only can reduce the driving voltage, but also can greatly improve the CE, PE and EQE at the same time, especially the device lifetime is improved by 10 times or more, which can well make up for the shortcomings of the current TADF device.

[0357] In summary, by using metal complexes containing structural ligand L a represented by Formula 1 in the light-emitting layer of the device, the TADF material can be efficiently sensitized, thereby obtaining a device with very excellent performance, which can obtain lower driving voltage, higher device efficiency (CE, PE and EQE) and very excellent device lifetime, and has very high application prospect.

[0358] It should be understood that the various embodiments described herein are merely examples and are not intended to limit the scope of the application. Therefore, as apparent from the foregoing disclosure, certain changes and modifications can be made without departing from the spirit of the application. For example, it is apparent that aspects of the application disclosed herein can be implemented in any of a variety of systems, including a computer, a microprocessor, a microcontroller, an application- specific integrated circuit, a digital signal processor, or the like. Additionally, it is apparent that features described herein can be incorporated into any of a variety of types of devices, including a computer, a mobile device, a personal digital assistant, a video game console, or the like. Furthermore, it is apparent that features described herein can be incorporated into any of a variety of types of devices, including a computer, a mobile device, a personal digital assistant, a video game console, or the like. Also, it is apparent that features described herein can be incorporated into any of a variety of types of devices, including a computer, a mobile device, a personal digital assistant

Claims

1. An organic electroluminescent device comprising: an anode, a cathode, and a light-emitting layer disposed between the anode and the cathode, the light-emitting layer comprising at least a metal complex and a thermally activated delayed fluorescence material; The metal complex comprises a metal M and a ligand L coordinated to the metal M a , the L a has a structure represented by Formula 1: wherein, Ring C y selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof; Ring C x an unsaturated fused ring having 10-30 ring atoms; G1and G2are at each occurrence, identically or differently, selected from a single bond, O, or S; R x identically or differently at each occurrence, denotes mono- or polysubstitution; R y identically or differently at each occurrence, denotes mono-, poly- or no substitution; R x and R y each occurrence is the same or different, selected from the group consisting of hydrogen, deuterium, halogen, a substituted or unsubstituted alkyl having from 1-20 carbon atoms, a substituted or unsubstituted cycloalkyl having from 3-20 ring carbon atoms, a substituted or unsubstituted heteroalkyl having from 1-20 carbon atoms, a substituted or unsubstituted heterocyclyl having from 3-20 ring atoms, a substituted or unsubstituted aralkyl having from 7-30 carbon atoms, a substituted or unsubstituted alkoxy having from 1-20 carbon atoms, a substituted or unsubstituted aryloxy having from 6-30 carbon atoms, a substituted or unsubstituted alkenyl having from 2-20 carbon atoms, a substituted or unsubstituted alkynyl having from 2-20 carbon atoms, a substituted or unsubstituted aryl having from 6-30 carbon atoms, a substituted or unsubstituted heteroaryl having from 3-30 carbon atoms, a substituted or unsubstituted alkylsilicon having from 3-20 carbon atoms, a substituted or unsubstituted arylsilane having from 6-20 carbon atoms, a substituted or unsubstituted alkyl germanium having from 3-20 carbon atoms, a substituted or unsubstituted aryl germanium having from 6-20 carbon atoms, a substituted or unsubstituted amino having from 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; at least one R x selected from cyano or fluoro; adjacent substituents R x , R y may optionally be joined to form a ring.

2. The organic electroluminescent device according to claim 1, wherein the ring C x comprises at least one five-membered unsaturated carbocyclic or five-membered unsaturated heterocyclic ring, which comprises at least one heteroatom selected from the group consisting of O, S, Se, N, Si and Ge; Preferably, said ring C x is selected from condensed rings comprising at least three rings fused.

3. The organic electroluminescent device according to claim 1 or 2, wherein the metal complex has the formula M(L a ) m (L b ) n (L c ) q structure, wherein the ligands L a , L b and L c are a first, second and third ligand, respectively, which coordinate to the metal M, the ligands L a , L b and L c may optionally be linked to form a polydentate ligand; L b and L c are the same or different monanionic bidentate ligands; m is selected from 1, 2 or 3, n is selected from 0, 1 or 2, q is selected from 0, 1 or 2, m+n+q is equal to the oxidation state of the metal M; when m is equal to or greater than 2, the plurality of L a are the same or different; when n is equal to 2, the two L b are the same or different; when q is equal to 2, the two L c are the same or different; Ligand L a having a structure represented by Formula 2: wherein, the metal M is selected from a metal having a relative atomic mass greater than 40; Ring C y each occurrence is the same or different selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof; G1and G2are at each occurrence, identically or differently, selected from a single bond, O, or S; X is at each occurrence, identically or differently, selected from the group consisting of O, S, Se, NR1, CR1R1, SiR1R1and GeR1R1; X1-X4are the same or different at each occurrence and are selected from C, CR x or N; and one of X1-X4is selected from C and is attached to ring C y and one of X1-X4is selected from C or N and is attached to G2; X5-X8are the same or different at each occurrence and are selected from CR x or N; R y identically or differently at each occurrence, denotes mono-, poly- or no substitution; R x , R y and R1are the same or different at each occurrence and are selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl of 1-20 carbon atoms, substituted or unsubstituted cycloalkyl of 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl of 1-20 carbon atoms, substituted or unsubstituted heterocyclyl of 3-20 ring atoms, substituted or unsubstituted aralkyl of 7-30 carbon atoms, substituted or unsubstituted alkoxy of 1-20 carbon atoms, substituted or unsubstituted aryloxy of 6-30 carbon atoms, substituted or unsubstituted alkenyl of 2-20 carbon atoms, substituted or unsubstituted alkynyl of 2-20 carbon atoms, substituted or unsubstituted aryl of 6-30 carbon atoms, substituted or unsubstituted heteroaryl of 3-30 carbon atoms, substituted or unsubstituted alkylsilyl of 3-20 carbon atoms, substituted or unsubstituted arylsilyl of 6-20 carbon atoms, substituted or unsubstituted alkylgermanyl of 3-20 carbon atoms, substituted or unsubstituted arylgermanyl of 6-20 carbon atoms, substituted or unsubstituted amino of 0-20 carbon atoms, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, hydroxy, mercapto, sulfinyl, sulfonyl, phosphino, and combinations thereof; at least one of X1-X8is CR x , and said R x is cyano or fluoro; adjacent substituents R x , R y and R1may optionally be linked to form a ring; Preferably, wherein said L b and L c is selected from any of the structures represented by any of the following groups: each occurrence is the same or different selected from any of the structures represented by any of the following groups: wherein, R a and R b each occurrence, identically or differently, represents mono-, poly- or no substitution; X b at each occurrence, is selected from the group consisting of: O, S, Se, NR N1 , CR C1 R C2 ; R a , R b , R c , R N1 , R C1 and R C2 are the same or different at each occurrence selected from the group consisting of hydrogen, deuterium, halogen, a substituted or unsubstituted alkyl having from 1-20 carbon atoms, a substituted or unsubstituted cycloalkyl having from 3-20 ring carbon atoms, a substituted or unsubstituted heteroalkyl having from 1-20 carbon atoms, a substituted or unsubstituted heterocyclyl having from 3-20 ring atoms, a substituted or unsubstituted aralkyl having from 7-30 carbon atoms, a substituted or unsubstituted alkoxy having from 1-20 carbon atoms, a substituted or unsubstituted aryloxy having from 6-30 carbon atoms, a substituted or unsubstituted alkenyl having from 2-20 carbon atoms, a substituted or unsubstituted alkynyl having from 2-20 carbon atoms, a substituted or unsubstituted aryl having from 6-30 carbon atoms, a substituted or unsubstituted heteroaryl having from 3-30 carbon atoms, a substituted or unsubstituted alkylsilicon having from 3-20 carbon atoms, a substituted or unsubstituted arylsilane having from 6-20 carbon atoms, a substituted or unsubstituted alkyl germanium having from 3-20 carbon atoms, a substituted or unsubstituted aryl germanium having from 6-20 carbon atoms, a substituted or unsubstituted amino having from 0-20 carbon atoms, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; adjacent substituents R a , R b , R c , R N1 , R C1 and R C2 may optionally be joined to form a ring.

4. The organic electroluminescent device according to claim 3, wherein G1 is a single bond, the ring C y is selected from any one of the following structures at each occurrence, identically or differently: wherein, R y identically or differently at each occurrence, denotes mono-, poly- or no substitution; R y and R y1 are each, identically or differently on each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; adjacent substituents R y may optionally be linked to form a ring; wherein "#" represents the position of attachment to the metal M, represents the position of attachment to X1, X2, X3or X4.

5. The organic electroluminescent device according to claim 3, wherein the metal M is selected from the group consisting of Cu, Ag, Au, Ru, Rh, Pd, Os, Ir and Pt; Preferably, the metal M is selected from Pt or Ir.

6. The organic electroluminescent device according to claim 3, wherein the metal complex has a formula Ir(L a ) m (L b ) 3-m structure, and has a structure represented by Formula 3: wherein, m is selected from 1, 2 or 3; when m is selected from 1, two L b are the same or different; when m is selected from 2 or 3, 2 or 3 L a are the same or different; X is selected from the group consisting of O, S, Se, NR1, CR1R1, SiR1R1and GeR1R1; X3-X8are selected independently from each occurrence from CR x or N; Y1-Y4are each, on the same or different occurrence, selected from CR y or N; R a and R b each occurrence, identically or differently, represents mono-, poly- or no substitution; R1, R x , R y , R a , R b are each, the same or different at each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; at least one of X3-X8is CR x , and said R x is cyano or fluoro; adjacent substituents R1, R x , R y , R a and R b may optionally be joined to form a ring.

7. The organic electroluminescent device according to claim 6, wherein at least one of X5 to X8 is CR x , and the R x is cyano or fluorine. Preferably, said X7or X8is CR x , and said R x is cyano or fluoro.

8. The organic electroluminescent device of claim 6, wherein the R x one is cyano or fluoro, and the other at least one R x or at least one R y is selected from the group consisting of deuterium, halogen, a substituted or unsubstituted alkyl having from 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl having from 3 to 20 ring carbon atoms, a substituted or unsubstituted heteroalkyl having from 1 to 20 carbon atoms, a substituted or unsubstituted heterocyclyl having from 3 to 20 ring atoms, a substituted or unsubstituted aralkyl having from 7 to 30 carbon atoms, a substituted or unsubstituted alkoxy having from 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy having from 6 to 30 carbon atoms, a substituted or unsubstituted alkenyl having from 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl having from 2 to 20 carbon atoms, a substituted or unsubstituted aryl having from 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, a substituted or unsubstituted alkylsilicon having from 3 to 20 carbon atoms, a substituted or unsubstituted arylsilane having from 6 to 20 carbon atoms, a substituted or unsubstituted alkyl germanium having from 3 to 20 carbon atoms, a substituted or unsubstituted aryl germanium having from 6 to 20 carbon atoms, a substituted or unsubstituted amino having from 0 to 20 carbon atoms, acyl, carbonyl, carboxyl, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; Preferably, said R x one is cyano or fluoro, and at least one other R x or at least one other R y selected from the group consisting of deuterium, halogen, substituted or unsubstituted alkyl having from 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having from 3 to 20 ring carbon atoms, substituted or unsubstituted aryl having from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having from 3 to 30 carbon atoms, substituted or unsubstituted alkylsilicon having from 3 to 20 carbon atoms, substituted or unsubstituted arylsilane having from 6 to 20 carbon atoms, substituted or unsubstituted amino having from 0 to 20 carbon atoms, cyano, hydroxy, mercapto, and combinations thereof; More preferably, said R x one of which is cyano or fluoro, and at least one other of which is x selected from the group consisting of deuterium, substituted or unsubstituted alkyl of from 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl of from 3 to 20 ring carbon atoms, substituted or unsubstituted aryl of from 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl of from 3 to 30 carbon atoms, and combinations thereof.

9. The organic electroluminescent device according to claim 3, wherein the L a is selected, on each occurrence, identically or differently, from the group consisting of Optionally, the L a1 to L a555 hydrogen in said L b is, at each occurrence, selected from the group consisting of: optionally, the L b1 to L b18 , L b20 to L b26 and L b31 to L b160 may be partially or totally substituted with deuterium; the L c is, at each occurrence, the same or different, selected from the group consisting of Optionally, the L c1 to L c50 hydrogen in the group of the formulae 10. The organic electroluminescent device according to claim 9, wherein the metal complex is selected from the group consisting of metal complex 1 to metal complex 614, metal complex 1 to metal complex 598 have the structure of Ir(L a )(L b )2, wherein both L b are identical, L a and L b correspond to the structures in the following table, respectively: the metal complex 599 to metal complex 614 are selected from the group consisting of the following structures:

11. The organic electroluminescent device according to claim 1, wherein the maximum emission wavelength in the photoluminescence spectrum of the metal complex is from 500 nm to 580 nm; Preferably, the maximum emission wavelength in the photoluminescence spectrum of the metal complex is from 510 nm to 560 nm.

12. The organic electroluminescent device according to claim 1, wherein the full width at half maximum in the photoluminescence spectrum of the metal complex is less than 80 nm; Preferably, the full width at half maximum in the photoluminescence spectrum of the metal complex is less than 60 nm; More preferably, the full width at half maximum in the photoluminescence spectrum of the metal complex is less than 40 nm.

13. The organic electroluminescent device according to claim 1, wherein the thermally activated delayed fluorescence material has a structure represented by formula 4: wherein, ring A, ring B, ring C, ring D, ring E are each independently selected from an unsaturated carbocyclic ring having 5 to 30 carbon atoms or an unsaturated heterocyclic ring having 3 to 30 carbon atoms; Z1, E1and E2are each independently selected from B, N, P, P=0, P=S, As, As=0, As=S, SiR Si1 or GeR Ge1 ; T1to T8are each independently selected from C, CR’ or N; a, b, c, d are each independently selected from 0 and 1; L1, L2, L3, L4are at each occurrence, identically or differently, selected from a single bond, O, S, Se, BR or NR; R’ represents at each occurrence, identically or differently, mono-, poly- or non-substitution; R, R', R Si1 and R Ge1 each occurrence is the same or different, selected from the group consisting of hydrogen, deuterium, halogen, a substituted or unsubstituted alkyl having from 1-20 carbon atoms, a substituted or unsubstituted cycloalkyl having from 3-20 ring carbon atoms, a substituted or unsubstituted heteroalkyl having from 1-20 carbon atoms, a substituted or unsubstituted heterocyclyl having from 3-20 ring atoms, a substituted or unsubstituted aralkyl having from 7-30 carbon atoms, a substituted or unsubstituted alkoxy having from 1-20 carbon atoms, a substituted or unsubstituted aryloxy having from 6-30 carbon atoms, a substituted or unsubstituted alkenyl having from 2-20 carbon atoms, a substituted or unsubstituted alkynyl having from 2-20 carbon atoms, a substituted or unsubstituted aryl having from 6-30 carbon atoms, a substituted or unsubstituted heteroaryl having from 3-30 carbon atoms, a substituted or unsubstituted alkylsilicon having from 3-20 carbon atoms, a substituted or unsubstituted arylsilane having from 6-20 carbon atoms, a substituted or unsubstituted alkyl germanium having from 3-20 carbon atoms, a substituted or unsubstituted aryl germanium having from 6-20 carbon atoms, a substituted or unsubstituted amino having from 0-20 carbon atoms, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, -BR”R”, and combinations thereof; Each time "R" appears, it is selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl groups having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl groups having 1-20 carbon atoms, substituted or unsubstituted heterocyclic groups having 3-20 ring atoms, substituted or unsubstituted aralkyl groups having 7-30 carbon atoms, substituted or unsubstituted alkoxy groups having 1-20 carbon atoms, substituted or unsubstituted aroxy groups having 6-30 carbon atoms, substituted or unsubstituted alkenyl groups having 2-20 carbon atoms, substituted or unsubstituted... Alkynyl groups having 2-20 carbon atoms, substituted or unsubstituted aryl groups having 6-30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3-30 carbon atoms, substituted or unsubstituted alkylsilyl groups having 3-20 carbon atoms, substituted or unsubstituted arylsilyl groups having 6-20 carbon atoms, substituted or unsubstituted alkylgermanium groups having 3-20 carbon atoms, substituted or unsubstituted arylgermanium groups having 6-20 carbon atoms, substituted or unsubstituted amino, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, hydroxyl, mercapto, sulfinyl, sulfonyl, phosphinyl, and combinations thereof having 0-20 carbon atoms; adjacent substituents R, R', R", R Si1 and R Ge1 may optionally be joined to form a ring.

14. The organic electroluminescent device of claim 13, wherein ring A, ring B, ring C, ring D and ring E are each independently selected from five-membered unsaturated carbon rings, aromatic rings having 6-18 carbon atoms or heteroaromatic rings having 3-18 carbon atoms; Preferably, ring A, ring B, ring C, ring D and ring E are each independently selected from benzene ring, pyridine ring, naphthyl ring, phenanthrene ring, anthracene ring, indene ring, fluorene ring, indole ring, carbazole ring, benzofuran ring, dibenzofuran ring, benzothiophene ring, dibenzothiophene ring, benzothiophene ring, dibenzoselenophene ring, dibenzoselenophene ring, cyclopentadiene ring, furan ring, thiophene ring, thiophene ring, or combinations thereof; More preferably, rings A, B, C, D, and E are selected from benzene rings.

15. The organic electroluminescent device as claimed in claim 13 or 14, wherein Z1 is selected from B, P=O or P=S, and E1 and E2 are each independently selected from N or P; preferably, Z1 is selected from B, and E1 and E2 are selected from N.

16. The organic electroluminescent device of claim 13 or 14, wherein L1, L2, L3, and L4 are selected from single bonds, BR, or NR each time they appear.

17. The organic electroluminescent device as claimed in claim 13 or 14, wherein a+b+c+d is greater than or equal to 1; preferably, a+d is greater than or equal to 1; more preferably, a is 0 or 1, and d is 1.

18. The organic electroluminescent device of claim 13, wherein the thermally activated delayed fluorescence material has a structure represented by formula 5-1 or formula 5-2: in, Each occurrence of R' indicates monosubstitution, polysubstitution, or no substitution, whether it is the same or different. R' is, the same or different at each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl of 1-20 carbon atoms, substituted or unsubstituted cycloalkyl of 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl of 1-20 carbon atoms, substituted or unsubstituted heterocyclyl of 3-20 ring atoms, substituted or unsubstituted aralkyl of 7-30 carbon atoms, substituted or unsubstituted alkoxy of 1-20 carbon atoms, substituted or unsubstituted aryloxy of 6-30 carbon atoms, substituted or unsubstituted alkenyl of 2-20 carbon atoms, substituted or unsubstituted alkynyl of 2-20 carbon atoms, substituted or unsubstituted aryl of 6-30 carbon atoms, substituted or unsubstituted heteroaryl of 3-30 carbon atoms, substituted or unsubstituted alkylsilicon of 3-20 carbon atoms, substituted or unsubstituted arylsilane of 6-20 carbon atoms, substituted or unsubstituted alkyl germanium of 3-20 carbon atoms, substituted or unsubstituted aryl germanium of 6-20 carbon atoms, substituted or unsubstituted amino of 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, -BR"R", and combinations thereof; R" is, the same or different at each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl of 1-20 carbon atoms, substituted or unsubstituted cycloalkyl of 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl of 1-20 carbon atoms, substituted or unsubstituted heterocyclyl of 3-20 ring atoms, substituted or unsubstituted aralkyl of 7-30 carbon atoms, substituted or unsubstituted alkoxy of 1-20 carbon atoms, substituted or unsubstituted aryloxy of 6-30 carbon atoms, substituted or unsubstituted alkenyl of 2-20 carbon atoms, substituted or unsubstituted alkynyl of 2-20 carbon atoms, substituted or unsubstituted aryl of 6-30 carbon atoms, substituted or unsubstituted heteroaryl of 3-30 carbon atoms, substituted or unsubstituted alkylsilicon of 3-20 carbon atoms, substituted or unsubstituted arylsilane of 6-20 carbon atoms, substituted or unsubstituted alkyl germanium of 3-20 carbon atoms, substituted or unsubstituted aryl germanium of 6-20 carbon atoms, substituted or unsubstituted amino of 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; adjacent substituents R' and R" can optionally be linked to form a ring.

19. The organic electroluminescent device according to claim 18, wherein said R’ is at each occurrence, identically or differently, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilicon with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, and combinations thereof; preferably wherein said R’ is at each occurrence, identically or differently, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, and combinations thereof.

20. The organic electroluminescent device according to claim 18, wherein multiple R’ are present in formula 5-1 or formula 5-2, at least one of said multiple R’ is selected from substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, or combinations thereof.

21. The organic electroluminescent device according to claim 1, wherein said thermally activated delayed fluorescence material is selected from the group consisting of compound DF-1 to compound DF-95: optionally, hydrogen in compound DF-1 to compound DF-95 can be partially or entirely replaced with deuterium.

22. The organic electroluminescent device according to claim 1, wherein the maximum emission wavelength in the photoluminescence spectrum of said thermally activated delayed fluorescence material is from 480 nm to 580 nm; preferably, the maximum emission wavelength in the photoluminescence spectrum of said thermally activated delayed fluorescence material is from 500 nm to 560 nm.

23. The organic electroluminescent device according to claim 1, wherein the full width at half maximum in the photoluminescence spectrum of said thermally activated delayed fluorescence material is less than 45 nm; preferably, the full width at half maximum in the photoluminescence spectrum of said thermally activated delayed fluorescence material is less than 35 nm.

24. A display device comprising the organic electroluminescent device according to any one of claims 1-23.

25. A composition comprising at least one metal complex comprising a metal M and a ligand L coordinated to the metal M and one thermally activated delayed fluorescence material, said L having a structure represented by Formula 1: a a ​​ wherein, Ring C y selected from an aromatic ring having 6-24 ring atoms, a heteroaromatic ring having 5-24 ring atoms, or a combination thereof; Ring C x an unsaturated fused ring having 10-30 ring atoms; G1and G2are at each occurrence, identically or differently, selected from a single bond, O, or S; R x identically or differently at each occurrence, denotes mono- or polysubstitution; R y identically or differently at each occurrence, denotes mono-, poly- or no substitution; R x and R y are each, identically or differently on each occurrence, selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl with 1-20 carbon atoms, substituted or unsubstituted heterocyclyl with 3-20 ring atoms, substituted or unsubstituted aralkyl with 7-30 carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryloxy with 6-30 carbon atoms, substituted or unsubstituted alkenyl with 2-20 carbon atoms, substituted or unsubstituted alkynyl with 2-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, substituted or unsubstituted alkylsilicon with 3-20 carbon atoms, substituted or unsubstituted arylsilane with 6-20 carbon atoms, substituted or unsubstituted alkyl germanium with 3-20 carbon atoms, substituted or unsubstituted aryl germanium with 6-20 carbon atoms, substituted or unsubstituted amino with 0-20 carbon atoms, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxyl, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof; at least one R x selected from cyano or fluoro; adjacent substituents R x , R y may optionally be joined to form a ring.

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