Copper complex and organic electroluminescent device

Abstract

The invention relates to the technical field of electronic materials, in particular to a copper complex and an organic electroluminescent device. The copper complex provided by the invention comprises a donor with the following structure and copper-carbene, the # imgabs0 # copper complex has a unique chelating space structure, hydrogen atoms and copper atoms can form metal hydrogen bond secondary interaction, the stability of the copper complex with the structure can be improved, and the organic electroluminescent device containing the copper complex has high external quantum efficiency and long device life.

Description

Technical Field

[0001] The invention relates to the technical field of electronic materials, and in particular to a copper complex and an organic electroluminescent device. Background Art

[0002] Organic light-emitting diode (OLED) technology, as an advanced optoelectronic device capable of achieving electro-optical conversion, has shown great potential in the fields of lighting and display due to its significant advantages such as low operating voltage, high energy conversion efficiency, flexible structure, fast response and wide operating temperature range.

[0003] In organic light-emitting diode (OLED) technology, luminescent materials have a crucial impact on the optoelectronic performance of the device. Since triplet excitons account for about 75% of the excitons generated under the action of the electric field during OLED operation, while singlet excitons account for 25%, efficient conversion of triplet excitons becomes the core of improving OLED performance. Currently, research on OLED luminescent materials mainly focuses on two strategies for capturing and utilizing triplet excitons: phosphorescent materials and thermally activated delayed fluorescence (TADF) materials. TADF materials have become a hot topic of research due to their advantages in conversion efficiency and cost control.

[0004] TADF materials can be divided into two categories: pure organic TADF materials and copper complex TADF materials. Pure organic TADF materials often face the problem of long emission lifetime and severe efficiency roll-off at high brightness. Long emission lifetime may lead to decreased stability of the device because longer-lived excitons are more likely to suffer from various degradation pathways in the device.

[0005] Copper complex TADF materials, especially linear complexes with carbene-metal-amide as ligands, are less studied and the device lifetime and efficiency of these materials are generally low. The carbene-metal-amide series of luminophores have rapidly become an important research direction due to their high photoluminescence quantum yields of up to 0.9-1.0 and the potential for sub-microsecond emission lifetimes. In addition, in addition to their relatively low cost and low toxicity, the filled d orbitals in these monovalent copper complexes inherently avoid internal non-radiative quenching of excited states through low-space dd* transitions. Copper complex materials remain a hot topic of research due to their unique optoelectronic properties. For example, the research on copper(I) complexes in the field of organic electroluminescent materials (OLEDs) has mainly focused on exploring their unique photophysical properties and how to apply these properties to high-efficiency and high-stability OLED devices. Copper(I) complexes can exhibit properties different from traditional fluorescent and phosphorescent materials due to their special electronic structure and coordination environment.

[0006] Although copper (I) complexes have the potential for application in organic light-emitting diodes (OLEDs), the linear carbene-metal-amine copper (I) complex materials in the prior art have insufficient performance, resulting in low device life and external quantum efficiency of the prepared organic electroluminescent devices. Summary of the invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art that the linear carbene-metal-amine copper (I) complex material has insufficient performance and the organic electroluminescent device prepared has low device life and external quantum efficiency. Thus, a copper complex and an organic electroluminescent device are provided.

[0008] Definitions of terms in this invention:

[0009] As used herein, the term "halogen" may include fluorine, chlorine, bromine or iodine.

[0010] As used in the present invention, the term "C1-C10 alkyl" refers to a monovalent substituent derived from a straight or branched chain saturated hydrocarbon having 1 to 30 carbon atoms, examples of which include but are not limited to methyl, ethyl, propyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl and hexyl.

[0011] “C 2-6 "Alkenyl" refers to alkenyl groups containing 2, 3, 4, 5 or 6 carbons;

[0012] “C 6-20 "Aryl" includes aromatic groups having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms;

[0013] “C 3-20 "Heteroaryl" refers to a heteroaryl group containing 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms;

[0014] In the present invention, the aromatic group includes a monocyclic, polycyclic or condensed-ring aromatic group, the rings may be interrupted by short non-aromatic units, and may contain a spiro structure. The aromatic group includes but is not limited to phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluorenyl, spirobifluorenyl, etc., and the arylene group includes but is not limited to phenylene, biphenylene, terphenylene, naphthylene, phenanthrylene, anthracenylene, fluorenylene, spirobifluorenyl, etc.

[0015] In the present invention, heteroaryl includes monocyclic, polycyclic or condensed ring heteroaryl, and the rings may be interrupted by short non-aromatic units, and the heteroatoms include nitrogen, oxygen, and sulfur. Heteroaryl includes, but is not limited to, furanyl, phenylthio, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothiophenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzimidazolyl, benzo thiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenoxazinyl, phenothiazinyl, phenanthridinyl, benzodioxolyl, dihydroacridinyl, and derivatives thereof; heteroarylene includes but is not limited to furanyl, phenylene thio, pyrroleyl yl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazolyl, pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, benzofuranyl, benzothiophenylene, isobenzofuranyl, dibenzofuranyl, dibenzothiophenylene, benzimidazolyl, oxazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenoxazinyl, phenothiazinyl, phenanthridinyl, benzodioxolyl, acridinyl, and derivatives thereof.

[0016] In the present invention, "C" refers to carbon and is not used as a synonym for other terms.

[0017] Indicates a connection key.

[0018] The scheme adopted by the present invention is as follows:

[0019] The present invention provides a copper complex, comprising a donor and copper-carbene;

[0020] The donor has a structure shown in the following formula A:

[0021]

[0022] Copper-carbene has the following structure:

[0023]

[0024] wherein X1 is selected from N or C-T1; X2 is selected from N or C-T2; T1 and T2 are each independently selected from H, halogen, cyano, alkylamino, nitro, carboxyl, trihalomethyl, alkoxy, C 1-10 Alkyl, C 2-6 Alkenyl, C 6-20 Aryl, C 3-20 heteroaryl;

[0025] X3 is selected from N or C; X4 is selected from N or C;

[0026] R1, R3, R4 are each independently selected from hydrogen, C 1-10 alkyl;

[0027] R2 is independently selected from hydrogen, C 6-20 Aryl.

[0028] It can be understood that for copper-carbene, the carbene fragment is coordinated to the metallic copper center in the form of an uncharged monodentate ligand.

[0029] As for the reasons why the linear carbene-metal-amine copper (I) complex material performance in the prior art is insufficient, the applicant has found after research that due to the linear coordination structure in the prior art, the copper metal center lacks protection, resulting in a low device life and external quantum efficiency of the prepared organic electroluminescent device, and thus provides the copper complex in the present application to improve the material properties, thereby making the device life and external quantum efficiency of the prepared organic electroluminescent device low.

[0030] Preferably, the copper complex has the structure shown below:

[0031]

[0032] Preferably, R1, R3, and R4 are each independently selected from hydrogen, C 1-6 alkyl;

[0033] Preferably, R1, R3, and R4 are each independently selected from a hydrogen atom, a methyl group, an isopropyl group, and a tert-butyl group;

[0034] Preferably, R2 is independently selected from hydrogen, C 6-15 Aryl;

[0035] Preferably, R2 is independently selected from hydrogen, phenyl, naphthyl, biphenyl.

[0036] Preferably, T1 and T2 are each independently selected from H, halogen, cyano, alkylamino, nitro, carboxyl, trihalomethyl, alkoxy, C 1-6 Alkyl, C 2-6 Alkenyl, C 6-15 Aryl, C 3-15 heteroaryl;

[0037] Preferably, T1 and T2 are each independently selected from H, halogen, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, phenyl, naphthyl, biphenyl, vinyl, propenyl, trihalomethyl, oxy, dimethylamino, nitro, and carboxyl;

[0038] Preferably, the halogen includes fluorine and chlorine;

[0039] Preferably, the trihalomethyl group includes a trifluoromethyl group.

[0040] Preferably, the copper-carbene has the structure shown below:

[0041]

[0042] Preferably, the donor has the following structure:

[0043]

[0044] Preferably, the copper complex has the structure shown below:

[0045]

[0046]

[0047]

[0048]

[0049] The above are some specific structural forms of copper complexes, but they are not limited to the chemical structures listed. All compounds based on the general structural formula such as the combination of formula A and formula B, and the combination of formula A and formula C should be included.

[0050] The present invention also provides a method for preparing the copper complex, and the specific steps and conditions of the preparation method are as follows:

[0051] S1. Compound A and compound B are reacted in a nitrogen atmosphere by a Buchwald coupling reaction to obtain a chelate donor unit in one step.

[0052] Reaction conditions: the alkaline source is sodium tert-butoxide; the catalyst is bis(dibenzylideneacetonepalladium); the additive is 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl; the solvent is xylene; and the temperature is 120°C.

[0053] S2, the chelate donor unit and the carbene copper chloride compound (Carbene-Cu-Cl) undergo coordination reaction under a nitrogen atmosphere to obtain the copper complex (compound of general formula 1)

[0054] Reaction conditions: In the first step, the alkaline source is sodium tert-butoxide; the solvent is toluene; stirring at room temperature for 2 hours.

[0055] In the second step, a carbene copper chloride compound is added and the reaction is continued for 2 hours to finally obtain the copper complex of general formula 1.

[0056] The synthesis route of the copper complex of the present invention is as follows:

[0057]

[0058] Among them, Carbene-Cu-Cl has the following structure:

[0059]

[0060] Wherein, X1-X4 and R1-R4 are the same as defined above.

[0061] The present invention also provides an organic electroluminescent device, which comprises a first electrode, a second electrode and a light-emitting layer located between the first electrode and the second electrode, wherein the light-emitting layer comprises any one or a combination of at least two of the above-mentioned copper complexes.

[0062] Preferably, the light-emitting layer comprises the copper complex and the organic functional material mentioned above, and in terms of mass percentage, the copper complex accounts for 0.01%-100%, and the organic functional material accounts for 0-99.9%.

[0063] It should be noted that the application of the copper complex of the present invention is not limited to the device composition, and the film thickness or constituent materials of each layer can be appropriately changed according to the basic physical properties of the specific compound structure of the present invention.

[0064] The method for preparing the organic device of the present invention is a conventional method in the art. Optionally, the preparation of the organic electroluminescent device comprises the following steps: using a glass substrate with ITO evaporated as a transparent support substrate, and sequentially evaporating each organic layer and metal electrode on the ITO film of the transparent support substrate.

[0065] The present invention also provides application of the organic electroluminescent device described above in electronic equipment.

[0066] Beneficial effects of the present invention:

[0067] The copper complex provided by the present invention includes a donor having a structure of formula A and a copper-carbene of formula B or formula C. Based on a linear monovalent copper complex of carbene-metal-amide type, by changing the spatial structure of the donor, the H atom of the chelate donor can effectively approach the copper metal atom to form a metal hydrogen bond, and the stability of the molecule is further enhanced under the condition of maintaining the TADF property; the pseudo-4-coordinate configuration allows the monovalent copper atom to improve the stability while also allowing it to act as a metal bridge, more effectively participate in the excited state formation of the molecule, and optimize the photophysical properties of the molecule; at the same time, due to the steric hindrance of the donor and the copper-carbene, the donor and the copper-carbene will present a certain torsion angle, so that the frontier orbit of the molecule is better distributed and separated, so that the oscillator strength of the molecule and the energy difference between the triplet and singlet excitons are further balanced and optimized, and the luminescent performance of the molecule is improved. In summary, the copper complex provided by the present invention has excellent photoluminescence and electroluminescence properties, and can make the prepared light-emitting device have a longer device life, higher luminescence efficiency and external quantum efficiency.

[0068] Furthermore, the flexibility of the carbene-metal-amide structure in the copper complex provided by the present invention allows the emission wavelength to be adjusted by adjusting the electron-donating ability of the donor unit or the electron-withdrawing ability of the acceptor unit, thereby optimizing the spectral characteristics of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0070] Figure 1 It is a structural diagram of the organic electroluminescent device in the device embodiment 1-11 of the present invention;

[0071] Figure 2 This is the absorption and emission spectrum of the copper complex Cu-37 prepared in Example 1 of the present invention;

[0072] Figure 3 This is the absorption and emission spectrum of the copper complex Cu-49 prepared in Example 2 of the present invention;

[0073] Figure 4 Absorption and emission spectra of the copper complex Cu-52 prepared in Example 3 of the present invention;

[0074] Figure 5 This is the absorption and emission spectrum of the copper complex Cu-61 prepared in Example 4 of the present invention;

[0075] Figure 6 This is the emission spectrum of the copper complex Cu-62 prepared in Example 5 of the present invention;

[0076] Figure 7 This is the absorption and emission spectrum of the copper complex Cu-64 prepared in Example 6 of the present invention;

[0077] Figure 8 This is the absorption and emission spectrum of the copper complex Cu-66 prepared in Example 7 of the present invention;

[0078] Fig. 9 This is the absorption and emission spectrum of the copper complex Cu-67 prepared in Example 8 of the present invention;

[0079] Fig.10 This is the absorption and emission spectrum of the copper complex Cu-73 prepared in Example 9 of the present invention;

[0080] Fig.11 This is a life decay curve diagram of the copper complex Cu-37 prepared in Example 1 of the present invention in the mCP film;

[0081] Fig.12 This is a life decay curve diagram of the copper complex Cu-49 prepared in Example 2 of the present invention in the mCP film;

[0082] Fig.13 This is a life decay curve diagram of the copper complex Cu-52 prepared in Example 3 of the present invention in the mCP film;

[0083] Fig.14 This is a life decay curve diagram of the copper complex Cu-61 prepared in Example 4 of the present invention in the mCP film;

[0084] Fig.15 This is a life decay curve diagram of the copper complex Cu-62 prepared in Example 5 of the present invention in the mCP film;

[0085] Fig.16 This is a life decay curve diagram of the copper complex Cu-66 prepared in Example 7 of the present invention in the mCP film;

[0086] Fig.17 This is a life decay curve diagram of the copper complex Cu-67 prepared in Example 8 of the present invention in the mCP film;

[0087] Fig.18 This is a life decay curve diagram of the copper complex Cu-73 prepared in Example 9 of the present invention in the mCP film;

[0088] Fig.19Electroluminescence graphs and electroluminescence quantum efficiency graphs of device embodiments 1-4 of the present invention based on Cu-49;

[0089] Fig. 20 Electroluminescence graphs and electroluminescence quantum efficiency graphs of device embodiments 5-8 of the present invention based on Cu-73;

[0090] Fig.21 The stability test diagram of the organic electroluminescent devices based on Cu-49 and Cu-73 in device examples 1 and 5 is shown.

[0091] Reference numerals:

[0092] 1-anode layer, 2-hole injection layer, 3-first hole transport layer, 4-second hole transport layer, 5-electron blocking layer, 6-light-emitting layer, 7-first electron transport layer, 8-second electron transport layer, 9-electron injection layer, 10-cathode layer, 100-glass substrate. DETAILED DESCRIPTION

[0093] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0094] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0095] The preparation method of the intermediate of some copper complexes is as follows:

[0096] Preparation of chelate donor unit DBC:

[0097] The synthetic route is as follows:

[0098]

[0099] 1-amino-2-bromonaphthalene (1.00 g, 4.5 mmol), 1-iodonaphthalene (1.72 g, 6.75 mmol), Pd2(dba)3 (206 mg, 0.23 mmol), XPhos (215 mg, 0.45 mmol) and sodium tert-butoxide (1.3 g, 13.54 mmol) were added to a 100 mL round-bottom flask, purged with argon three times, 30 mL of ultra-dry xylene (Xylenes) solution was added, stirring was started, and the temperature was slowly raised to 120 ° C for 24 hours. After the reaction was completed, the reaction system was filtered using diatomaceous earth, and the filtrate was distilled under reduced pressure and then purified by column chromatography (eluent was dichloromethane: petroleum ether system) to obtain a white solid product DBC (yield 38%). 1 H NMR (500MHz, CD2Cl2) δ9.68 (s, 1H), 8.37-8.31 (m, 2H), 8.20 (d, J = 8.5Hz, 2H), 8.05 (d, J = 8.1Hz, 2H), 7.73 (d, J=8.5Hz, 2H), 7.68 (ddd, J=8.2, 6.9, 1.2Hz, 2H), 7.57 (ddd, J=8.2, 6.9, 1.2Hz, 2H).

[0100] Preparation of chelate donor unit DBC-F:

[0101] The synthetic route is as follows:

[0102]

[0103] 1-amino-2-bromo-4-fluoronaphthalene (1.08 g, 4.5 mmol), 1-iodonaphthalene (1.72 g, 6.75 mmol), Pd2(dba)3 (206 mg, 0.23 mmol), XPhos (215 mg, 0.45 mmol) and sodium tert-butoxide (1.3 g, 13.54 mmol) were added to a 100 mL round-bottom flask, purged with argon three times, added with 30 mL of ultra-dry xylene solution, stirred, and slowly heated to 120 ° C for 24 hours. After the reaction, the reaction system was filtered using diatomaceous earth, and the filtrate was distilled under reduced pressure and then purified by column chromatography (eluent was dichloromethane: petroleum ether system) to obtain a white solid product DBC-F (yield 42%). 1 H NMR (500MHz, CDCl3) δ9.44(s,1H),8.28(dd,J=12.2,8.3Hz,3H),8.10(d,J=8.5Hz,1H),8.05(d,J=8 .1Hz,1H),7.83(d,J=10.7Hz,1H),7.71(d,J=8.4Hz,2H),7.69-7.60(m,2H),7.58(t,J=7.6Hz,1H).

[0104] Preparation of chelate donor unit DBC-CN:

[0105] The synthetic route is as follows:

[0106]

[0107] 4-amino-3-bromo-1-cyanonaphthalene (1.11 g, 4.5 mmol), 1-iodonaphthalene (1.72 g, 6.75 mmol), Pd2(dba)3 (206 mg, 0.23 mmol), XPhos (215 mg, 0.45 mmol) and sodium tert-butoxide (1.3 g, 13.54 mmol) were added to a 100 mL round-bottom flask, purged with argon three times, added with 30 mL of ultra-dry xylene solution, stirred, and slowly heated to 120 ° C for 24 hours. After the reaction, the reaction system was filtered using diatomaceous earth, and the filtrate was distilled under reduced pressure and then purified by column chromatography (eluent was dichloromethane: petroleum ether system) to obtain a white solid product DBC-CN (yield 32%). 1 H NMR (500MHz, DMSO) δ13.30(s,1H),9.10(s,1H),8.93(d,J=8.2Hz,1H),8.79(d,J=8.2Hz,1H),8.39(d,J=8.5Hz,1H),8.27(d,J=8 .2Hz,1H),8.12(d,J=8.1Hz,1H),7.90(t,J=7.5Hz,1H),7.83(dd,J=10.2,8.0Hz,2H),7.76(t,J=7.5Hz,1H),7.66-7.61(m,1H).

[0108] Preparation of chelate donor unit DBC-N:

[0109] The synthetic route is as follows:

[0110]

[0111] 1-amino-2-bromonaphthalene (1.00 g, 4.5 mmol), 1-iodonaphthalene (1.72 g, 6.75 mmol), Pd2(dba)3 (206 mg, 0.23 mmol), XPhos (215 mg, 0.45 mmol) and sodium tert-butoxide (1.3 g, 13.54 mmol) were added to a 100 mL round-bottom flask, purged with argon three times, added with 30 mL of ultra-dry xylene solution, stirred, and slowly heated to 120 ° C for 24 hours. After the reaction, the reaction system was filtered using diatomaceous earth, and the filtrate was distilled under reduced pressure and then purified by column chromatography (eluent was dichloromethane: petroleum ether system) to obtain a white solid product DBC-N (yield 33%).1 H NMR (400MHz, DMSO) δ13.26 (s, 1H), 9.70 (s, 1H), 8.75 (d, J = 9.3Hz, 2H), 8.42 ( d,J=8.6Hz,1H),8.24-8.09(m,2H),7.89-7.70(m,4H),7.63(t,J=7.5Hz,1H).

[0112] Preparation of chelate donor unit DBC-NF:

[0113] The synthetic route is as follows:

[0114]

[0115] 1-amino-2-bromo-4-fluoronaphthalene (1.08 g, 4.5 mmol), 1-iodonaphthalene (1.72 g, 6.75 mmol), Pd2(dba)3 (206 mg, 0.23 mmol), XPhos (215 mg, 0.45 mmol) and sodium tert-butoxide (1.3 g, 13.54 mmol) were added to a 100 mL round-bottom flask, purged with argon three times, added with 30 mL of ultra-dry xylene solution, stirred, and slowly heated to 120 ° C for 24 hours. After the reaction, the reaction system was filtered using diatomaceous earth, and the filtrate was distilled under reduced pressure and then purified by column chromatography (eluent was dichloromethane: petroleum ether system) to obtain a white solid product DBC-NF (yield 27%). 1 H NMR (500MHz, DMSO) δ13.32(s,1H),9.68(s,1H),8.80(d,J=8.3Hz,1H),8.72(dd,J=6.2,3.4H z,1H),8.32(d,J=11.0Hz,1H),8.26-8.15(m,2H),7.88(t,J=7.6Hz,1H),7.81-7.70(m,3H).

[0116] Preparation of chelate donor unit DBC-NMe2:

[0117] The synthetic route is as follows:

[0118]

[0119] 1-amino-2-bromonaphthalene (1.00 g, 4.5 mmol), 4-iodo-1-dimethylaminonaphthalene (2 g, 6.75 mmol), Pd2(dba)3 (206 mg, 0.23 mmol), XPhos (215 mg, 0.45 mmol) and sodium tert-butoxide (1.3 g, 13.54 mmol) were added to a 100 mL round-bottom flask, purged with argon three times, added with 30 mL of ultra-dry xylene solution, stirred, and slowly heated to 120 ° C for 24 hours. After the reaction was completed, the reaction system was filtered using diatomaceous earth, and the filtrate was distilled under reduced pressure and then purified by column chromatography (eluent was dichloromethane: petroleum ether system) to obtain a white solid product DBC-NMe2 (yield 9%). 1 H NMR (400MHz, DMSO) δ12.61(s,1H),8.74(dd,J=7.3,3.3Hz,2H),8.37(d,J=8.5Hz,1H),8.28(d,J=8 .5Hz,1H),8.05(d,J=8.0Hz,1H),7.97(s,1H),7.74-7.62(m,3H),7.62-7.49(m,2H),2.91(s,6H).

[0120] Example 1

[0121] This embodiment provides a method for preparing a copper complex Cu-37, which specifically comprises the following steps:

[0122]

[0123] Chelate donor unit DBC (50 mg, 0.186 mmol) and sodium tert-butoxide (53 mg, 56 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding carbene copper chloride (100 mg, 0.186 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a white powder Cu-37 (yield 91%). 1H NMR (400MHz, CD2Cl2) δ8.56(d,J=8.2Hz,2H),8.09(d,J=8.4Hz,2H),7.87(d,J=8.1Hz,2H),7.50(t,J=7.8Hz,2H),7.43(d,J=8.5 Hz,2H),7.38(dd,J=6.3,3.1Hz,2H),7.28(t,J=6.9Hz,6H),7.06-6.89(m,4H),2.70-2.50(m,4H),0.98(dd,J=23.8,6.9Hz,24H).

[0124] Example 2

[0125] This embodiment provides a method for preparing a copper complex Cu-49, which specifically comprises the following steps:

[0126]

[0127] Chelate donor unit DBC (50 mg, 0.186 mmol) and sodium tert-butoxide (53 mg, 56 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.186 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane:n-hexane system to obtain a yellow powder Cu-49 (yield 82%). 1 H NMR (500MHz, CD2Cl2) δ8.49(s,4H),8.05(d,J=8.4Hz,2H),7.85(d,J=8.1Hz,2H),7.47(t,J=7.8Hz,2H),7.41(d ,J=8.3Hz,2H),7.32-7.20(m,6H),6.98(t,J=7.5Hz,2H),2.48(p,J=6.9Hz,4H),0.96(dd,J=11.8,6.8Hz,24H).

[0128] Example 3

[0129] This embodiment provides a method for preparing the copper complex Cu-52, which specifically comprises the following steps:

[0130]

[0131] The chelate donor unit DBC-CN (54 mg, 0.186 mmol) and sodium tert-butoxide (53 mg, 56 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.186 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a yellow powder Cu-52 (yield 89%). 1 H NMR (500MHz, CDCl3) δ8.59(s,1H),8.52(d,J=7.0Hz,3H),8.43(d,J=8.1Hz,1H),8.27( d,J=8.2Hz,1H),8.08(d,J=8.4Hz,1H),7.90(d,J=8.1Hz,1H),7.55(d,J=8.5Hz,1H),7 .46(t,J=7.8Hz,3H),7.32(d,J=7.2Hz,1H),7.21(d,J=7.8Hz,4H),7.05(d,J=7.9Hz,1 H), 6.98 (s, 1H), 2.41 (p, J = 6.9Hz, 4H), 1.00 (d, J = 6.9Hz, 12H), 0.91 (d, J = 6.9Hz, 12H).

[0132] Example 4

[0133] This embodiment provides a method for preparing the copper complex Cu-61, which specifically comprises the following steps:

[0134]

[0135] Chelate donor unit DBC (46 mg, 0.172 mmol) and sodium tert-butoxide (50 mg, 0.516 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.172 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a white powder Cu-61 (yield 75%). 1H NMR (400MHz, CD2Cl2) δ8.68(d,J=8.2Hz,2H),8.53(dd,J=4.3,1.8Hz,1H),8.10(d,J=8.4Hz,2H),7.88(d,J=8.1Hz,2H),7.42(dd,J=1 8.1,6.6Hz,6H),7.35-7.15(m,6H),7.00(t,J=7.6Hz,2H),3.12-3.01(m,1H),2.63(s,4H),1.38(d,J=6.9Hz,6H),1.10-0.92(m,24H).

[0136] Example 5

[0137] This embodiment provides a method for preparing the copper complex Cu-62, which specifically comprises the following steps:

[0138]

[0139] The chelate donor unit DBC-N (46 mg, 0.172 mmol) and sodium tert-butoxide (50 mg, 0.516 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.172 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a white powder Cu-62 (yield 82%).

[0140] Example 6

[0141] This embodiment provides a method for preparing the copper complex Cu-64, which specifically comprises the following steps:

[0142]

[0143] The chelate donor unit DBC-CN (50 mg, 0.172 mmol) and sodium tert-butoxide (50 mg, 0.516 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.172 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a white powder Cu-64 (yield 80%). 1H NMR (500MHz, CDCl3) δ8.66(d,J=8.2Hz,1H),8.59(s,1H),8.57(d,J=8.3Hz,1H),8.52(d,J=4.7Hz,1H),8.27 (d,J=8.3Hz,1H),8.08(d,J=8.4Hz,1H),7.89(d,J=8.1Hz,1H),7.54(d,J=8.4Hz,1H),7.41(dd,J=15.1,8.2 Hz,3H),7.37-7.29(m,3H),7.21(d,J=7.8Hz,2H),7.12(s,2H),7.02(t,J=7.5Hz,1H),6.96(d,J=7.8Hz,1H) ,3.02(p,J=7.0Hz,1H),2.52(s,4H),1.37(d,J=6.9Hz,6H),1.01(d,J=6.8Hz,12H),0.94(d,J=6.7Hz,12H).

[0144] Example 7

[0145] This embodiment provides a method for preparing the copper complex Cu-66, which specifically comprises the following steps:

[0146]

[0147] The chelate donor unit DBC-F (49 mg, 0.172 mmol) and sodium tert-butoxide (50 mg, 0.516 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.172 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a white powder Cu-66 (yield 86%). 1H NMR (500MHz, DMSO) δ8.75(d,J=8.2Hz,1H),8.70(d,J=8.1Hz,1H),8.61(d,J=4.7Hz,1H),8.05(dd ,J=16.6,8.3Hz,2H),7.90(dd,J=20.6,9.6Hz,2H),7.76(d,J=8.2Hz,1H),7.60-7.57(m,1H),7.45 (d,J=7.5Hz,2H),7.39(d,J=8.5Hz,1H),7.36-7.31(m,3H),7.27(d,J=12.2Hz,3H),7.14(t,J=7.5 Hz,1H),2.96(q,J=6.9Hz,1H),2.68(s,4H),1.24(d,J=6.8Hz,7H),0.99(dt,J=31.6,6.3Hz,24H).

[0148] Example 8

[0149] This embodiment provides a method for preparing the copper complex Cu-67, which specifically comprises the following steps:

[0150]

[0151] The chelate donor unit DBC-NF (46 mg, 0.172 mmol) and sodium tert-butoxide (50 mg, 0.516 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.172 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane:n-hexane system to obtain a white powder Cu-67 (yield 63%).

[0152] Example 9

[0153] This embodiment provides a method for preparing the copper complex Cu-73, which specifically comprises the following steps:

[0154]

[0155] Chelate donor unit DBC (63 mg, 0.234 mmol) and sodium tert-butoxide (67 mg, 0.702 mmol) were added to a 100 mL round-bottom flask, purged with argon 3 times, 10 mL of toluene solvent was added thereto, and the reaction system was stirred at room temperature for 2 hours. Subsequently, the corresponding metal copper chloride (100 mg, 0.234 mmol) was added to the reaction system, and the reaction was continued for 2 hours. After the reaction was completed, the mixture was filtered through filter paper, the filtrate was distilled under reduced pressure, and then recrystallized with a dichloromethane: normal hexane system to obtain a white powder Cu-73 (yield 92%). 1 H NMR (400MHz, CD2Cl2) δ8.87(d,J=7.8Hz,2H),8.62(s,2H),8.08(d,J=8.5Hz,2H),7.90(d, J=7.0Hz,2H),7.43(d,J=8.4Hz,2H),7.40-7.31(m,4H),7.31-7.20(m,6H),2.31(s,13H).

[0156] Device Example 1

[0157] This embodiment provides an organic electroluminescent device, such as Figure 1 As shown, the anode layer 1, the hole injection layer 2, the first hole transport layer 3, the second hole transport layer 4, the electron blocking layer 5, the light emitting layer 6, the first electron transport layer 7, the second electron transport layer 8, the electron injection layer 9 and the cathode layer 10 are sequentially arranged on the glass substrate 100 from bottom to top.

[0158] The materials for manufacturing the organic electroluminescent device are as follows:

[0159]

[0160] The anode layer 1 is made of ITO material, i.e. indium tin oxide material; the hole injection layer 2 is made of 1,2-hexaazatriphenylene (HAT-CN); the hole transport layer 3 is made of 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC). The first electron blocking layer 4 is made of tris(4-carbazolyl-9-ylphenyl)amine (TCTA); the second electron blocking layer 5 is made of 3,3'-bis(9H-carbazolyl-9-yl)-1,1'-biphenyl; 3,3'-bis(9H-carbazolyl-9-yl)-1,1'-biphenyl (mCBP); the light-emitting layer 6 is formed by co-doping a host material and a guest material, wherein the host material is 5-(3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl)-7,7-dimethyl-5,7-dihydroindeno[2,1-b]carbazole (DMIC-TRZ), and the guest material is 1,2-dihydro-1,3-diphenyl-2,4-dihydro-1,7 ... The copper complex of the present invention is selected as the main material, and the doping amount of the guest material accounts for 1% of the total mass of the main material and the guest material; the material of the electron transport layer 7 is selected: 2,4,6-tris[3-(diphenylphosphinoyl)phenyl]-1,3,5-triazole (POT2T); the material of the first electron injection layer 8 is selected from (1-(4-(10-([1,1'-biphenyl]-4-yl)anthracene-9-yl)phenyl)-2-ethyl-1H-benzo[d]-imidazole) (ANT-BIZ); the material of the second electron injection layer 9 is selected from Liq (8-hydroxyquinoline lithium); the material of the cathode layer 10 is selected from metal Al material.

[0161] The device structure is ITO / HAT-CN (5nm) / TAPC (30nm) / TCTA (15nm) / mCBP (10nm) / DMIC-TRZ:X (45nm) / PO-T2T (20nm) / ANT-BIZ (30nm) / Liq (2nm) / Al (100nm), where X is the copper complex Cu-49.

[0162] Device Examples 2-8

[0163] The manufacturing processes of the devices of device embodiments 2-8 are completely similar to that of device embodiment 1, except that the guest materials in the light-emitting layer are different, or the doping amount of the guest material accounts for different percentages of the total mass of the host material and the guest material. The specific parameters are shown in Table 1.

[0164] Table 1 is the light emitting layer materials of device examples 2-8

[0165]

[0166] Testing and characterization of copper complexes:

[0167] The absorption spectrum and emission spectrum of the copper complex solution of the present invention are tested, wherein the solution is a toluene solution or a tetrahydrofuran solution, and the concentration of the copper complex in the toluene solution is 1×10 -5mol L -1 The concentration of the copper complex in tetrahydrofuran solution is 1×10 -5 mol L -1 ;

[0168] The emission spectrum, lifetime and lifetime decay of the copper complex of the present invention in mCP (9,9'-(1,3-phenyl)di-9H-carbazole) film were tested. The doping concentration of the copper complex in the mCP (9,9'-(1,3-phenyl)di-9H-carbazole) film was 5wt%.

[0169] Figure 2 This is the absorption and emission spectrum of the copper complex Cu-37 prepared in Example 1 of the present invention, wherein: Figure 2 a is the absorption spectrum of Cu-37 in toluene solution, Figure 2 b is the emission spectrum of Cu-37 in toluene solution, Figure 2 c is the emission spectrum of Cu-37 in mCP film;

[0170] Figure 3 This is the absorption and emission spectrum of the copper complex Cu-49 prepared in Example 2 of the present invention, wherein: Figure 3 a is the absorption spectrum of Cu-49 in toluene solution, Figure 3 b is the emission spectrum of Cu-49 in toluene solution, Figure 3 c is the emission spectrum of Cu-49 in mCP film;

[0171] Figure 4 The absorption and emission spectra of the copper complex Cu-52 prepared in Example 3 of the present invention, wherein: Figure 4 a is the absorption spectrum of Cu-52 in toluene solution, Figure 4 b is the emission spectrum of Cu-52 in toluene solution, Figure 4 c is the emission spectrum of Cu-52 in mCP film;

[0172] Figure 5 This is the absorption and emission spectrum of the copper complex Cu-61 prepared in Example 4 of the present invention, wherein: Figure 5 a is the absorption spectrum of Cu-61 in toluene solution, Figure 5 b is the emission spectrum of Cu-61 in toluene solution, Figure 5 c is the emission spectrum of Cu-61 in mCP film;

[0173] Figure 6 This is the emission spectrum of the copper complex Cu-62 prepared in Example 5 of the present invention, wherein: Figure 6 a is the emission spectrum of Cu-62 in toluene solution, Figure 6b is the emission spectrum of Cu-62 in mCP film;

[0174] Figure 7 This is the absorption and emission spectrum of the copper complex Cu-64 prepared in Example 6 of the present invention, wherein: Figure 7 a is the absorption spectrum of Cu-64 in toluene solution, Figure 7 b is the emission spectrum of Cu-64 in toluene solution, Figure 7 c is the emission spectrum of Cu-64 in mCP film;

[0175] Figure 8 This is the absorption and emission spectrum of the copper complex Cu-66 prepared in Example 7 of the present invention, wherein: Figure 8 a is the emission spectrum of Cu-66 in toluene solution, Figure 8 b is the emission spectrum of Cu-66 in mCP film;

[0176] Fig. 9 This is the absorption and emission spectrum of the copper complex Cu-67 prepared in Example 8 of the present invention, wherein: Fig. 9 a is the emission spectrum of Cu-67 in toluene solution, Fig. 9 b is the emission spectrum of Cu-67 in mCP film;

[0177] Fig.10 This is the absorption and emission spectrum of the copper complex Cu-73 prepared in Example 9 of the present invention, wherein: Fig.10 a is the absorption spectrum of Cu-73 in toluene solution, Fig.10 b is the emission spectrum of Cu-73 in toluene solution, Fig.10 c is the emission spectrum of Cu-73 in mCP film;

[0178] Fig.11 This is a life decay curve diagram of the copper complex Cu-37 prepared in Example 1 of the present invention in the mCP film;

[0179] Fig.12 This is a life decay curve diagram of the copper complex Cu-49 prepared in Example 2 of the present invention in the mCP film;

[0180] Fig.13 This is a life decay curve diagram of the copper complex Cu-52 prepared in Example 3 of the present invention in the mCP film;

[0181] Fig.14 This is a life decay curve diagram of the copper complex Cu-61 prepared in Example 4 of the present invention in the mCP film;

[0182] Fig.15This is a life decay curve diagram of the copper complex Cu-62 prepared in Example 5 of the present invention in the mCP film;

[0183] Fig.16 This is a life decay curve diagram of the copper complex Cu-66 prepared in Example 7 of the present invention in the mCP film;

[0184] Fig.17 This is a life decay curve diagram of the copper complex Cu-67 prepared in Example 8 of the present invention in the mCP film;

[0185] Fig.18 This is a lifetime decay curve diagram of the copper complex Cu-73 prepared in Example 9 of the present invention in the mCP film.

[0186] Test Example 1

[0187] The organic electroluminescent devices provided in device examples 1-4 were tested, and the guest material was selected as the copper complex Cu-49. The current-brightness-voltage characteristics of the devices were measured by a Keithley source measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) with a calibrated silicon photodiode. All tests were completed in the room temperature atmosphere. The test results are shown in Tables 2 and Fig.19 ,in Fig.19 b is the electroluminescence diagram of the device embodiments 1-4 of the present invention based on the copper complex Cu-49, Fig.19 a is the electroluminescent quantum efficiency diagram of device embodiments 1-4 of the present invention based on the copper complex Cu-49.

[0188] Table 2 Device performance test results

[0189]

[0190] [a] Electroluminescence wavelength; [b] External quantum efficiency; [c] Efficiency roll-off; [d] Current efficiency; [e] Lumen efficiency; [f] Maximum brightness;

[0191] like Fig.19 As shown in the figure, the organic electroluminescent device prepared by the present invention using the copper complex Cu-49 as the guest material and with a doping concentration of 1% can have a maximum luminous brightness of 232325 cd m -2 , the maximum current efficiency is 78.6A -1 , the maximum lumen efficiency is 76.8lm W -1 , the maximum external quantum efficiency is as high as 29.5%.

[0192] Test Example 2

[0193] The organic electroluminescent device provided in device embodiment 1 was subjected to a stability test. The guest material was selected as the copper complex Cu-49. The device was encapsulated with a glass cover by UV-curing adhesive in a nitrogen-filled glove box. The device was then taken out of the glove box and the brightness of the working device was measured at a constant current density using an OLED life test system (FS-MP64, Suzhou FSTAR Scientific Instrument Co., Ltd., China). All tests were completed in the room temperature atmosphere. Fig.21 a. The present invention uses copper complex Cu-49 as the guest material and prepares a doped luminescent OLED with a doping concentration of 1%, and the initial brightness is 3000 cd m -2 LT 95 (LT 95 The luminance decay time (defined as the time taken for 5% brightness decay) was 59 hours.

[0194] Test Example 3

[0195] The organic electroluminescent devices provided in device examples 5-8 were tested, and the guest material was selected as the copper complex Cu-73. The current-brightness-voltage characteristics of the devices were measured by a Keithley source measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) with a calibrated silicon photodiode. All tests were completed in the room temperature atmosphere. The test results are shown in Tables 3 and Fig. 20 ,in Fig. 20 b is the electroluminescence image of the device embodiment 5-8 of the present invention based on the copper complex Cu-73, Fig. 20 a is the electroluminescent quantum efficiency diagram of device embodiments 5-8 of the present invention based on the copper complex Cu-73.

[0196] Table 3 Device performance test results

[0197]

[0198]

[0199] [a] Electroluminescence wavelength; [b] External quantum efficiency; [c] Efficiency roll-off; [d] Current efficiency; [e] Lumen efficiency; [f] Maximum brightness;

[0200] like Fig. 20 As shown in the figure, the organic electroluminescent device prepared by the present invention using the copper complex Cu-73 as the guest material and with a doping concentration of 1% has a maximum luminous brightness of 235271 cd m -2 , the maximum current efficiency is 84.1A -1 , the maximum lumen efficiency is 80.0lm W -1 , the maximum external quantum efficiency is as high as 28.9%.

[0201] Test Example 4

[0202] The organic electroluminescent device provided in device embodiment 5 was subjected to stability test. The guest material was selected as copper complex Cu-73. The device was encapsulated with a glass cover by UV curing adhesive in a nitrogen-filled glove box. Then, the device was taken out of the glove box and the brightness of the working device was measured at a constant current density using an OLED life test system (FS-MP64, Suzhou FSTAR Scientific Instrument Co., Ltd., China). All tests were completed in room temperature atmosphere. Fig.21 b. The present invention uses the copper complex Cu-73 as the guest material and prepares a doped luminescent OLED with a doping concentration of 1%, and the initial brightness is 3000 cd m -2 LT 95 (LT 95 The time taken for the brightness to decay by 5% is 68 hours.

[0203] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A copper complex, characterized in that Includes donor and copper-carbene; The donor has a structure shown in the following formula A: Copper-carbene has the following structure: wherein X1 is selected from N or C-T1; X2 is selected from N or C-T2; T1 and T2 are each independently selected from H, halogen, cyano, alkylamino, nitro, carboxyl, trihalomethyl, alkoxy, C 1-10 Alkyl, C 2-6 Alkenyl, C 6-20 Aryl, C 3-20 heteroaryl; X3 is selected from N or C; X4 is selected from N or C; R1, R3, R4 are each independently selected from hydrogen, C 1-10 alkyl; R2 is independently selected from hydrogen, C 6-20 Aryl.

2. The copper complex according to claim 1, characterized in that The copper complex has the structure shown below:

3. The copper complex according to claim 1 or 2, characterized in that R1, R3, R4 are each independently selected from hydrogen, C 1-6 alkyl; Preferably, R1, R3, and R4 are each independently selected from a hydrogen atom, a methyl group, an isopropyl group, and a tert-butyl group; Preferably, R2 is independently selected from hydrogen, C 6-15 Aryl; Preferably, R2 is independently selected from hydrogen, phenyl, naphthyl, biphenyl.

4. The copper complex according to any one of claims 1 to 3, characterized in that T1 and T2 are each independently selected from H, halogen, cyano, alkylamino, nitro, carboxyl, trihalomethyl, alkoxy, C 1-6 Alkyl, C 2-6 Alkenyl, C 6-15 Aryl, C 3-15 heteroaryl; Preferably, T1 and T2 are each independently selected from H, halogen, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, phenyl, naphthyl, biphenyl, vinyl, propenyl, trihalomethyl, oxy, dimethylamino, nitro, and carboxyl; Preferably, the halogen includes fluorine and chlorine; Preferably, the trihalomethyl group includes a trifluoromethyl group.

5. The copper complex according to any one of claims 1 to 4, characterized in that The copper-carbene has the structure shown below:

6. The copper complex according to any one of claims 1 to 5, characterized in that The donor has the following structure:

7. The copper complex according to any one of claims 1 to 5, characterized in that The copper complex has the structure shown below:

8. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and a light-emitting layer located between the first electrode and the second electrode, and the light-emitting layer comprises any one or a combination of at least two of the copper complexes according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The light-emitting layer comprises the copper complex according to any one of claims 1 to 7 and an organic functional material, wherein, by mass percentage, the copper complex accounts for 0.01% to 100%, and the organic functional material accounts for 0 to 99.9%.

10. Use of the organic electroluminescent device according to claim 8 or 9 in electronic equipment.

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