Organometallic compound and organic light-emitting layer material

Abstract

The invention relates to the technical field of organic photoelectric materials, in particular to an organic metal compound and an organic light-emitting layer material. The dEST-2 value of the organic metal compound is selected to be 0.0001 eVlt; dEST-2lt, DEST-2lt; and 0.30 eV of a compound. After the compound is applied to the organic light-emitting device, the organic light-emitting device has the characteristics of long service life, high efficiency and low driving voltage.

Description

[0001] This invention claims priority to Chinese Patent Application No. 202511394601X, entitled "Organometallic Compounds and Organic Light-Emitting Layer Materials", the contents of which are incorporated in full into and form part of the original description of this invention. Technical Field

[0002] This invention relates to the field of organic optoelectronic materials technology, and more specifically, to organometallic compounds and organic light-emitting layer materials. Background Technology

[0003] Organic semiconductor materials belong to the category of novel optoelectronic materials. Their large-scale development began in 1977 with the discovery of doped polyethylene, whose conductivity reached copper levels, by Hideki Shirakawa, A. Heeger, and A. McDiamid. Subsequently, in 1987, C. Tang et al. of Kodak invented the organic small-molecule light-emitting diode (OLED). OLEDs utilize organic thin films that emit light when a voltage is applied to the device. OLEDs are becoming an increasingly popular technology for applications such as flat panel displays, lighting, and backlighting.

[0004] For a variety of reasons, optoelectronic devices utilizing organic materials are becoming increasingly popular. For example, organic materials used in device fabrication are relatively inexpensive, giving organic optoelectronic devices a cost advantage over inorganic devices. Furthermore, the inherent properties of organic materials (such as their flexibility) make them suitable for specific applications, such as fabrication on flexible substrates. Organic optoelectronic devices include organic light-emitting diodes / devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials offer performance advantages over conventional materials; for example, the emission color of an OLED can be achieved through the design of the luminescent material structure. OLEDs can include one or more luminescent layers to achieve a desired spectrum. Currently, the rapid decrease in efficiency of phosphorescent OLEDs at high brightness remains a problem, leading to low efficiency and short lifetimes when phosphorescent materials are used in organic light-emitting devices.

[0005] Currently, TADF materials possess higher emission efficiency, higher singlet energy levels, and higher stability. When using TADF-sensitized fluorescent devices and conventional fluorescent materials as emitters, the process involves co-evaporating TADF as a dopant along with the host material and the fluorescent emitter material to form the emitting layer. When electrons and holes recombine to form excitons in the host material, these excitons first transfer energy to the TADF material. Through the antisystem crossing capability of TADF, electrons from the triplet state are transferred to the singlet state. Then, the TADF material transfers all of its singlet energy to the conventional fluorescent material (a process called FRET). Finally, the conventional fluorescent material emits fluorescence, a process known as superfluorescence. Throughout this process, the TADF material itself does not emit light; instead, it collects energy and transfers it to the fluorescent emitter material. Because the sensitized fluorescence is emitted by the conventional fluorescent material, the sensitized fluorescent emitter's spectrum combines the narrow spectrum and long lifetime of ordinary fluorescence with the high efficiency of TADF, making it suitable for OLED displays. Therefore, there is still much room for improvement in meeting the above requirements of existing TADF materials, and the industry urgently needs to develop new materials as sensitized fluorescent OLED materials.

[0006] Therefore, how to provide an organic electroluminescent material with long lifespan, high efficiency, and low driving voltage is a problem that urgently needs to be solved by those skilled in the art.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide organometallic compounds and organic light-emitting layer materials. Embodiments of this invention provide a novel organometallic compound, which, when used in an organic electroluminescent device, enables the organic electroluminescent device to possess characteristics of long lifetime, high efficiency, and low driving voltage.

[0009] This invention is implemented as follows: In a first aspect, embodiments of the present invention provide an organometallic compound having a La ligand with the structure shown in Formula I: , R1, R2, R3, and R4 are each independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trifluoromethyl, methyl, deuterated methyl, substituted or unsubstituted C2-C15 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C6-C30 heteroaryl, and their heteroatoms contain at least one of O, S, N, Si, Ge, and Se; and R1, R2, R3, and R4 must have at least two identical or different fluorine, trifluoromethyl, and cyano groups; R aR b R c and R d Each of the following is independently selected from hydrogen, deuterium, tritium, halogen, cyano, trifluoromethyl, methyl, deuterated methyl, trimethylgermanium, trimethylsilyl, substituted or unsubstituted C2-C15 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, wherein the heteroatom contains at least one of O, S, N, Si, Ge and Se; p, q, m and n are each independently selected from 1 to the maximum permissible substitution on the ring. Two adjacent substituents can connect to each other to form a ring; X1 and X2 are independently selected from C and N, respectively; and when X1 is selected from N, the six-membered ring is a pyridine ring. The dashed lines represent carbon-metal covalent bonds or nitrogen-metal coordination bonds formed with metals.

[0010] Secondly, embodiments of the present invention provide an organic light-emitting layer material, which includes a host material and a phosphorescent dopant material and / or a TADF material; both the phosphorescent dopant material and the TADF material can be selected from the above-mentioned organometallic compounds.

[0011] The present invention has the following beneficial effects: The La ligand in the organometallic compound provided in the embodiments of the present invention changes the spatial configuration and stereostructure between molecules by linking biphenyls with fluorine, trifluoromethyl, cyano and other groups at specific positions as the parent nucleus of dibenzofuran or azadibenzofuran, setting the molecular orientation, adjusting the steric hindrance, and matching the structure of the organic electroluminescent device of the present invention. This results in the organic metal compound being used in the organic electroluminescent device, which in turn gives the organic electroluminescent device the characteristics of long lifetime, high efficiency and low driving voltage. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 The 1H NMR spectrum of the organometallic compound provided in Example 1 of this invention; Figure 2 The 1H NMR spectrum of the organometallic compound provided in Example 2 of this invention; Figure 3 The EL spectrum of the bottom-emission device formed by compounds 964 and 965 provided in Test Example 2 of the present invention; Figure 4 The EL spectrum of the bottom-emitting device formed by compounds i and j provided in Test Example 2 of the present invention; Figure 5 This is a comparison graph of the EL spectrum and device results of the bottom-emission superfluorescent device provided in Test Example 3 of the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0015] In a first aspect, embodiments of the present invention provide an organometallic compound with the following structural formula: M(La)m(Lb)n, where M represents a metal, such as Ir and Pt. m is any value between 1 and 3, such as 1, 2, or 3; n is any value between 0 and 2, such as 0, 1, or 2; m+n equals the oxidation state of metal M. When m is greater than 2, the multiple Las are the same or different from each other; when n is 2, the two Lbs are the same or different from each other.

[0016] Further, La represents the La ligand with the structure shown in Formula I below: , R1, R2, R3, and R4 are each independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trifluoromethyl, methyl, deuterated methyl, substituted or unsubstituted C2-C15 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C6-C30 heteroaryl, and their heteroatoms contain at least one of O, S, N, Si, Ge, and Se; and R1, R2, R3, and R4 must have at least two identical or different fluorine, trifluoromethyl, and cyano groups.

[0017] R a R b R c and R d Each of the following is independently selected from hydrogen, deuterium, tritium, halogen, cyano, trifluoromethyl, methyl, deuterated methyl, trimethylgermanium, trimethylsilyl, substituted or unsubstituted C2-C15 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, wherein the heteroatom contains at least one of O, S, N, Si, Ge and Se.

[0018] p, q, m, and n are each independently selected from 1 to the maximum allowable substitution on the ring. For example, p can be any value between 1 and 5, such as 1, 2, 3, 4, or 5. That is, R b The benzene ring may include one R b 2 R b 3 Rs b 4 Rs b Or 5 Rs b Or, for example, q can be any value between 1 and 4; for example, 1, 2, 3, or 4. That is to say, R c The benzene ring may include one R c 2 R c 3 Rs c Or 4 Rs c .

[0019] In Formula I, two adjacent substituents can connect to form a ring. For example, R3 and R4 can fused together to form a ring; or two adjacent R... b They can fused into rings, or two adjacent Rs c They can be fused together to form rings.

[0020] X1 and X2 are independently selected from C and N, respectively; and when X1 is selected from N, the six-membered ring is a pyridine ring; that is, if R c For multiple substitution, multiple R C It did not fuse into a ring. Furthermore, CM covalent bonds and NM coordination bonds are formed in the structure of Equation 1.

[0021] In a preferred embodiment of the present invention, R1, R2, R3 and R4 are each independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trifluoromethyl, methyl, deuterated methyl, substituted or unsubstituted C2-C10 alkyl, substituted or unsubstituted C3-C15 cycloalkyl, substituted or unsubstituted C6-C18 aryl and substituted or unsubstituted C6-C18 heteroaryl, and their heteroatoms contain at least one of O, S, N, Si, Ge and Se.

[0022] R a R b R c and R d Each of the following is independently selected from hydrogen, deuterium, tritium, halogen, cyano, trifluoromethyl, trimethylsilyl, methyl, deuterated methyl, substituted or unsubstituted C2-C10 alkyl, substituted or unsubstituted C3-C15 cycloalkyl, substituted or unsubstituted C6-C18 aryl and substituted or unsubstituted C6-C18 heteroaryl, wherein the heteroatom contains at least one of O, S, N, Ge, Si and Se.

[0023] Furthermore, R1, R2, R3, and R4 are each independently selected from hydrogen, deuterium, fluorine, cyano, trifluoromethyl, methyl, deuterated methyl, substituted or unsubstituted C2-C6 alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C6-C15 aryl, substituted or unsubstituted C6-C15 heteroaryl, and their heteroatoms contain at least one of O, S, N, Si, Ge, and Se.

[0024] R a R b R c and R d Each of the following is independently selected from hydrogen, deuterium, fluorine, cyano, trifluoromethyl, trimethylsilyl, methyl, deuterated methyl, substituted or unsubstituted C2-C6 alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C6-C15 aryl, substituted or unsubstituted C6-C15 heteroaryl, wherein the heteroatom contains at least one of O, S, N, Si, and Se.

[0025] In the embodiments of the present invention, the La ligand is selected from any one of the structural formulas shown in Formulas 1-1 to 1-35 below:

[0026] .

[0027] All hydrogen atoms in Formula I and the structures shown in Formulas 1-1 to 1-35 may be substituted with or not substituted with deuterium. Furthermore, the selection of groups in Formulas 1-1 to 1-35 is subject to the aforementioned group restrictions.

[0028] More specifically, in the embodiments of the present invention, the La ligand is selected from any one of the groups shown in the following structural formulas:

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] ;

[0040] .

[0041] Furthermore, the DEST-1 value of the La ligand with the structure shown in Equation I is 0.5~2.0 eV. The La ligand is considered to have the following properties when it meets the following requirements: a) X1 and X2 are different from each other and are independently selected from C and N, respectively; b) Metal M is Ir or Pt; c) Formation of CM covalent bonds and NM coordinate bonds; d) When X1 is selected from N, the six-membered ring is pyridine; The combination of the La ligand with the central metal results in that when the DEST gap value is significantly reduced to less than 1 / 3, and the DEST-2 value ranges from 0.20 eV < dEST-2 < 0.50 eV, preferably 0.23 eV ≤ dEST-2 < 0.40 eV, the organometallic compound can be used as a phosphorescent doping material. Or The combination of the La ligand with the central metal results in that when the DEST gap value is significantly reduced to less than 1 / 3, and the dEST-2 value ranges between 0.0001 eV < DEST-2 < 0.30 eV, preferably between 0.0001 eV < DEST-2 ≤ 0.20 V, the organometallic compound can be used as a TADF material.

[0042] It should be noted that the DEST value is the energy difference between the lowest excited singlet state energy level E(S1) and the lowest excited triplet state energy level E(T1) of the compound.

[0043] Furthermore, La and Lb can be arbitrarily linked to form a multi-site ligand. And Lb is selected from the Lb ligands shown in the following structural formula: , where, R5-R 15 are each independently selected from - hydrogen, - D, - T, - CN, - F, - CT3, - CF3, - CH2F, - CHF2, methyl, ethyl, propyl, butyl, pentyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, C1-C6 alkyl groups that are fully or partially substituted by deuterium, substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C6-C30 heteroaryl groups, and substituted or unsubstituted C2-C6 alkynyl groups.

[0044] R5-R 15 Two adjacent substituents in can be connected to each other to form a ring to constitute an aryl or heteroaryl group. For example, R6 and R7 can be fused to form a fused ring. The formed aryl or heteroaryl groups include but are not limited to , , , , , , , , , ; where, represents the connection site, R e 、R f 、R g 、R h and R i are each independently selected from the following groups, hydrogen (H), deuterium (- D), tritium (- T), cyano (- CN), fluoro (- F), trichloromethyl (- CT3), trifluoromethyl (- CF 3）The following are all of the following: difluoromethyl (-CHF2), fluoromethyl (-CH2F), methyl, ethyl, propyl, butyl, pentyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, C1-C6 alkyl that is wholly or partially substituted with deuterium, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl, and substituted or unsubstituted C2-C6 alkynyl.

[0045] Meanwhile, in formulas Lb-1 and Lb-2, all hydrogen atoms are independently substituted with or not substituted with deuterium.

[0046] It should be noted that in the embodiments of the present invention, the number of carbon atoms of aryl, heteroaryl, cycloalkyl, alkyl and alkynyl groups in the terms "substituted or unsubstituted C2-C15 alkyl", "substituted or unsubstituted C3-C20 cycloalkyl", "substituted or unsubstituted C6-C30 aryl", "substituted or unsubstituted C6-C30 heteroaryl", "substituted or unsubstituted C2-C10 alkyl", "substituted or unsubstituted C3-C15 cycloalkyl", "substituted or unsubstituted C6-C18 aryl", "substituted or unsubstituted C6-C18 heteroaryl", "substituted or unsubstituted C2-C6 alkyl", "substituted or unsubstituted C3-C12 cycloalkyl", "substituted or unsubstituted C6-C15 aryl", and "substituted or unsubstituted C6-C15 heteroaryl" represents the total number of heteroatoms and carbon atoms constituting the unsubstituted aryl, unsubstituted alkynyl, unsubstituted alkyl or unsubstituted heteroaryl groups, without considering the number of carbon atoms in the substituents.

[0047] In the embodiments of this invention, "substituted or unsubstituted" means substituted by one, two or more substituents selected from the following: hydrogen, deuterium, halogen group, cyano, trifluoromethyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, naphthyl, anthracene, phenanthrene, thiophene, furanyl, pyrrole, benzothiophene, benzofuranyl, pyridyl, indolyl, cyclopentyl, cyclohexyl, adamantane, or substituted by two or more substituents linked together from the substituents shown above, or without substituents. The hydrogen atoms in the above groups can all be deuterated.

[0048] In this embodiment of the invention, Lb is selected from any one of the ligands shown in the following structural formulas:

[0049]

[0050]

[0051]

[0052] .

[0053] Furthermore, the organometallic compound is selected from any one of the compounds shown in the following structural formulas: IrLa(Lb)2, Ir(La)2Lb, Ir(La)3, PtLa(Lb) and Pt(La)2, wherein La is selected from any one of the functional groups composed of La1 to La739 each time it appears, and Lb is selected from any one of the functional groups composed of Lb1 to Lb148.

[0054] For example, the structural formula of an organometallic complex is shown below: IrLa(Lb)2, where the two Lb values ​​are identical, and La and Lb correspond to the structures shown in the table below: .

[0055] Secondly, embodiments of the present invention provide a method for preparing an organometallic compound, which can be prepared by methods known to those skilled in the art.

[0056] For example, refer to the following common knowledge: Organometallic Chemistry (6th Edition), Robert H. Crabtree, published by East China University of Science and Technology Press, Shanghai, September 00, 2017, ISBN: 978-7-5628-5111-0, page 388.

[0057] Organic Chemistry and Optoelectronic Materials Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0058] Alternatively, the following reaction procedure is preferred for preparation, and the specific synthetic route is as follows: ; The limitations in the above formula are the same as those mentioned above, and will not be repeated here.

[0059] The specific synthesis steps and conditions of this invention are illustrated in the following embodiments: Step 1 specifically includes the following steps: Under nitrogen atmosphere, raw material A (1.0 eq) and raw material B (1.0 eq) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 70℃-90℃, and refluxed for 4-12 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 1 is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. Step 2 specifically includes the following steps: Under nitrogen atmosphere, cool to -70℃ to -80℃ and dissolve intermediate 1 (1.0 eq) in tetrahydrofuran. Slowly add n-butyllithium (1.1 eq) to the solution of intermediate 1 (1.0 eq). After reacting for 2-4 hours, slowly add triisopropyl borate solution to the reaction flask, raise to room temperature, and continue the reaction for 4-12 hours. Detect the reaction using thin-layer chromatography. After the reaction is complete, add dilute hydrochloric acid to precipitate a solid, which is then filtered to obtain intermediate 2. Step 3 specifically includes the following steps: Under nitrogen atmosphere, intermediate 2 (1.0 eq) and raw material C (1.0 eq) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added, stirred evenly, heated to 70℃-90℃, and refluxed for 4-12 h. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. After the filtrate is cooled to room temperature, it is washed three times with water, and the organic phase is retained. Then, the aqueous phase is extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 3 is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. Step 4 specifically includes the following steps: Under nitrogen atmosphere, intermediate 3 (1.0 eq) is dissolved in dichloromethane, cooled to -10℃, boron tribromide (1.0 eq) is added, stirred evenly, and reacted for 2-4 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, water is slowly added to quench the reaction, and the mixture is allowed to stand for phase separation. The organic phase is retained, and then the aqueous phase is extracted with dichloromethane. The organic phases are combined and concentrated. Intermediate 4 is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. Step 5 specifically includes the following steps: Under nitrogen atmosphere, intermediate 4 (1.0 eq) is dissolved in DMF, potassium carbonate (2.2 eq) is added, stirred evenly, heated to 110℃-130℃, refluxed for 4-6 h, the reaction is detected by thin layer chromatography, after the reaction is completed, cooled to room temperature, the reaction solution is poured into ice water and stirred, a solid is precipitated, and filtered to obtain intermediate 5; Step 6 specifically includes the following steps: Under nitrogen atmosphere, raw material D (1.0 eq) and raw material E (1.0 eq) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution, stirred until homogeneous, heated to 70℃-90℃, and refluxed for 4-12 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the solution is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 6 is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. Step 7 specifically includes the following steps: Under nitrogen atmosphere, cool to -70℃ to -80℃ and dissolve intermediate 6 (1.0 eq) in tetrahydrofuran. Slowly add n-butyllithium (1.1 eq) to the solution of intermediate 6 (1.0 eq). After reacting for 2-4 hours, slowly add triisopropyl borate solution to the reaction flask, raise to room temperature, and continue the reaction for 4-12 hours. Detect the reaction using thin-layer chromatography. After the reaction is complete, add dilute hydrochloric acid to precipitate the solid, and filter to obtain intermediate 7. Step 8 specifically includes the following steps: Under nitrogen atmosphere, intermediates 5 and 7 are added to a mixed solution of toluene, ethanol, and water. Palladium acetate (0.05 eq), X-Phos (0.01 eq), and cesium carbonate (2.0 eq) are added and stirred until homogeneous. The mixture is heated to 100°C and refluxed for 10 hours. The reaction is detected by thin-layer chromatography. After the reaction is complete, the temperature is slightly lowered, and the mixture is filtered using diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature, and the solvent is removed using a rotary evaporator. The remaining substance is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=10:4) to obtain Formula I.

[0060] Furthermore, in this embodiment of the invention, taking the organic complex IrLa(Lb)2 as an example, the preparation process of the organic complex is described as follows;

[0061] Wherein, Lb1, Lb2 and Formula I are raw materials before coordination, and the other limitations in the above formula are the same as those mentioned above, and will not be repeated.

[0062] Step 1 specifically includes the following steps: Under a nitrogen atmosphere, ligand Lb-1 (4.0 eq) or Lb-2 (4.0 eq) is added to a reaction vessel, followed by the sequential addition of IrCl3·3H2O (1.0 eq), ethylene glycol ether, and water. The mixture is stirred until homogeneous, heated to 130℃-150℃, and reacted for 24 h. The reaction is detected using thin-layer chromatography. After the reaction is complete, the mixture is cooled to room temperature, filtered, washed three times each with methanol and n-hexane, and dried at 60℃ to obtain intermediate 8. Step 2 specifically includes the following steps: Under nitrogen atmosphere, intermediate 8 (1.0 eq) and silver trifluoromethanesulfonate (2.0 eq) are added to a mixed solution of isopropanol and DCM, stirred until homogeneous, and reacted at room temperature for 12 h. The reaction is detected by thin-layer chromatography. After the reaction is complete, the mixture is filtered with diatomaceous earth to remove salts and catalysts, washed three times with DCM, the filtrate is collected, and the solvent is removed using a rotary evaporator. The filtrate is then dried at 60 °C to obtain intermediate 9. Step 3 specifically includes the following steps: Under nitrogen atmosphere, intermediate 9 (1.0 eq) and formula I (1.5 eq) are added to ethanol, and the temperature is raised to 100℃-120℃ for 16-18 h. The reaction is detected by thin-layer chromatography. After the reaction is completed, the mixture is cooled to room temperature, filtered with diatomaceous earth to remove salts and catalysts, and washed three times each with methanol and n-hexane. The obtained solid is dissolved in DCM, the organic phase is collected, and the solvent is removed using a rotary evaporator. The remaining substance is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=10:4) to obtain the organometallic compound.

[0063] Secondly, embodiments of the present invention provide an organic light-emitting layer material, which includes a host material and a phosphorescent dopant material and / or a TADF material; both the phosphorescent dopant material and the TADF material can be selected from the above-mentioned organometallic compounds.

[0064] Thirdly, embodiments of the present invention provide an organic electroluminescent device, which includes an anode (second electrode), a cathode (first electrode), and an organic material layer disposed between the anode and the cathode, wherein the organic material layer includes at least one of the layered structures formed by organometallic compounds as described above.

[0065] The organic material layer includes a light-emitting layer, which comprises a host material and a dopant material, wherein the dopant material comprises an organometallic compound.

[0066] Furthermore, the organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, or an electron injection layer. Specifically, the organic electroluminescent device includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode arranged sequentially.

[0067] In embodiments of the present invention, a substrate can be used below the first electrode or above the second electrode. The substrate is made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, a thin-film transistor (TFT) can also be incorporated into the substrate used for a display.

[0068] The first electrode can be formed by sputtering or depositing a material for use as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. Furthermore, the anode material can also be selected from materials and combinations thereof that facilitate hole injection, in addition to the anode materials listed above, including known materials suitable for use as anodes. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof. Besides the cathode materials listed above, the cathode material can also be a material and combination thereof that facilitates electron injection, including known materials suitable for use as cathodes.

[0069] The organic material layer can be formed on the electrode using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as the organic material layer can be small organic molecules, large organic molecules, polymers, and combinations thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a monolayer hole transport layer (HTL), including monolayer hole transport layers containing only one compound and monolayer hole transport layers containing multiple compounds. The hole transport region can also be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0070] The material of the hole transport layer may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), aromatic amine derivatives as shown in HT-1 to HT-27 below, or any combination thereof.

[0071]

[0072]

[0073] However, it is not limited to the materials mentioned above.

[0074] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-27 described above, or one or more compounds of HI-1 to HI-3 described below; alternatively, one or more compounds of HT-1 to HT-27 can be used to dope one or more compounds of HI-1 to HI-3 described below.

[0075] However, it is not limited to the materials mentioned above.

[0076] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0077] In embodiments of the present invention, the electron transport layer material may be selected from, but is not limited to, one or more combinations of ET-1 to ET36 listed below.

[0078]

[0079]

[0080] However, it is not limited to the above-mentioned materials.

[0081] When an organometallic compound is used only as a phosphorescent dopant in an organic electroluminescent device, it is selected from one or more combinations of organometallic compounds listed below.

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] .

[0088] When an organometallic compound is used as both a phosphorescent dopant and a TADF in an organic electroluminescent device, it is selected from, but not limited to, one or more combinations of organometallic compounds listed below.

[0089]

[0090]

[0091]

[0092] .

[0093] Furthermore, the organic electroluminescent device may also include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or more combinations of the following: LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca.

[0094] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0095] Example 1 This embodiment provides an organometallic compound, namely compound number 11, and the specific synthesis steps are as follows: ; Step 1 specifically includes the following steps: Under nitrogen atmosphere, raw material A-a17 (1.0 eq) (CAS No.: 352535-97-8) and raw material B-a17 (1.0 eq) (CAS No.: 94665-63-1) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 90°C, and refluxed for 12 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 1 (yield 83.1%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0096] Step 2 specifically includes the following steps: Under nitrogen atmosphere, intermediate 1 (1.0 eq) is dissolved in tetrahydrofuran at -70℃. Butyllithium (1.1 eq) is slowly added to the solution of intermediate 1 (1.0 eq). After reacting for 4 hours, triisopropyl borate solution is slowly added to the reaction flask. The mixture is then brought to room temperature and reacted for another 12 hours. The reaction is detected using thin-layer chromatography. After the reaction is complete, dilute hydrochloric acid is added, and a solid precipitates. The solid is then filtered to obtain intermediate 2 (yield 75.3%).

[0097] Step 3 specifically includes the following steps: Under nitrogen atmosphere, intermediate 2 (1.0 eq) and raw material C-a17 (1.0 eq) (CAS No.: 174913-10-1) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 90°C, and refluxed for 12 h. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 3 (yield 83.6%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0098] Step 4 specifically includes the following steps: Under nitrogen atmosphere, intermediate 3 (1.0 eq) is dissolved in dichloromethane, cooled to -10℃, boron tribromide (1.0 eq) is added, stirred evenly, and reacted for 3 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, water is slowly added to quench the reaction, and the mixture is allowed to stand for phase separation. The organic phase is retained, and then the aqueous phase is extracted with dichloromethane. The organic phases are combined and concentrated. Intermediate 4 (yield 51.4%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0099] Step 5 specifically includes the following steps: Under nitrogen atmosphere, intermediate 4 (1.0 eq) is dissolved in DMF, potassium carbonate (2.2 eq) is added, stirred evenly, heated to 110°C, and refluxed for 6 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is lowered to room temperature, the reaction solution is poured into ice water and stirred, a solid is precipitated, and filtered to obtain intermediate 5 (yield 80.4%).

[0100] Step 6 specifically includes the following steps: Under nitrogen atmosphere, raw material D-a17 (1.0 eq) (CAS No.: 98-80-6) and raw material E-a17 (1.0 eq) (CAS No.: 74336-47-3) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 90°C, and refluxed for 12 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water. The organic phase is retained, and the aqueous phase is extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 6 (yield 82.7%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0101] Step 7 specifically includes the following steps: Under nitrogen atmosphere, intermediate 6 (1.0 eq) is dissolved in tetrahydrofuran at -70℃. Butyllithium (1.1 eq) is slowly added to the solution of intermediate 6 (1.0 eq). After reacting for 4 hours, triisopropyl borate solution is slowly added to the reaction flask. The mixture is then brought to room temperature and the reaction continues for 12 hours. The reaction is detected using thin-layer chromatography. After the reaction is complete, dilute hydrochloric acid is added, and a solid precipitates. The solid is then filtered to obtain intermediate 7 (yield 71.1%).

[0102] Step 8 specifically includes the following steps: Under nitrogen atmosphere, intermediates 5 and 7 are added to a mixed solution of toluene, ethanol and water. Palladium acetate (0.05 eq), X-Phos (0.01 eq), and cesium carbonate (2.0 eq) are added and stirred until homogeneous. The mixture is heated to 100°C and refluxed for 10 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered using diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature, and the solvent is removed using a rotary evaporator. The remaining substance is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=10:4) to obtain ligand La17 (yield 84.2%).

[0103]

[0104] Specifically, the synthesis steps are as follows: Step 1 specifically includes the following steps: Under nitrogen atmosphere, ligand Lb8 (4.0 eq) (CAS No.: 27012-22-2) was added to a reaction vessel, followed by IrCl3·3H2O (1.0 eq), ethylene glycol ether, and water. The mixture was stirred until homogeneous, heated to 130°C, and reacted for 24 hours. The reaction was detected using thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed three times each with methanol and n-hexane, and dried at 60°C to obtain intermediate 8 (yield 63.3%). Step 2 specifically includes the following steps: Under nitrogen atmosphere, intermediate 8 (1.0 eq) and silver trifluoromethanesulfonate (2.0 eq) are added to a mixed solution of isopropanol and DCM, stirred until homogeneous, and reacted at room temperature for 12 h. The reaction is detected by thin-layer chromatography. After the reaction is complete, the mixture is filtered with diatomaceous earth to remove salts and catalysts, washed three times with DCM, the filtrate is collected, and the solvent is removed using a rotary evaporator. The filtrate is then dried at 60 °C to obtain intermediate 9 (yield 70.3%). Step 3 specifically includes the following steps: Under nitrogen atmosphere, intermediate 9 (1.0 eq) and La17 (1.5 eq) were added to ethanol, heated to 120°C, and reacted for 16 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth to remove salts and catalysts, and washed three times each with methanol and n-hexane. The resulting solid was dissolved in DCM, the organic phase was collected, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=10:4) to obtain organometallic compound 11 (yield 36.4%).

[0105] Characterization: See the 1H NMR spectrum of organometallic compound 11. Figure 1 .

[0106] HPLC purity: >99.95%.

[0107] Mass spectrometry test: The test value is 962.79.

[0108] Elemental analysis: Test values ​​are: C, 66.08; H, 3.85; F, 3.99; N, 4.45; O, 1.73.

[0109] Example 2 This embodiment provides an organometallic compound, namely compound number 512, and the specific synthesis steps are as follows: ; Step 1 specifically includes the following steps: Under nitrogen atmosphere, raw material A-a69 (1.0 eq) (CAS No.: 352535-97-8) and raw material B-a69 (1.0 eq) (CAS No.: 94665-63-1) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 90°C, and refluxed for 12 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 1 (yield 83.9%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0110] Step 2 specifically includes the following steps: Under nitrogen atmosphere, intermediate 1 (1.0 eq) is dissolved in tetrahydrofuran at -70℃. Butyllithium (1.1 eq) is slowly added to the solution of intermediate 1 (1.0 eq). After reacting for 4 hours, triisopropyl borate solution is slowly added to the reaction flask. The mixture is then brought to room temperature and reacted for another 12 hours. The reaction is detected using thin-layer chromatography. After the reaction is complete, dilute hydrochloric acid is added to precipitate a solid, which is then filtered to obtain intermediate 2 (yield 74.7%).

[0111] Step 3 specifically includes the following steps: Under nitrogen atmosphere, intermediate 2 (1.0 eq) and raw material C-a69 (1.0 eq) (CAS No.: 174913-10-1) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 90°C, and refluxed for 12 h. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 3 (yield 84.5%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0112] Step 4 specifically includes the following steps: Under nitrogen atmosphere, intermediate 3 (1.0 eq) is dissolved in dichloromethane, cooled to -10℃, boron tribromide (1.0 eq) is added, stirred evenly, and reacted for 3 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, water is slowly added to quench the reaction, and the mixture is allowed to stand for phase separation. The organic phase is retained, and then the aqueous phase is extracted with dichloromethane. The organic phases are combined and concentrated. Intermediate 4 (yield 50.9%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0113] Step 5 specifically includes the following steps: Under nitrogen atmosphere, intermediate 4 (1.0 eq) is dissolved in DMF, potassium carbonate (2.2 eq) is added, stirred evenly, heated to 110℃, and refluxed for 6 h. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is lowered to room temperature, the reaction solution is poured into ice water and stirred, a solid is precipitated, and filtered to obtain intermediate 5 (yield 81.6%).

[0114] Step 6 specifically includes the following steps: Under nitrogen atmosphere, raw material D-a69 (1.0 eq) (CAS No.: 98-80-6) and raw material E-a69 (1.0 eq) (CAS No.: 2375-96-4) are added to a mixed solution of toluene, ethanol and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added to the solution. The mixture is stirred until homogeneous, heated to 90°C, and refluxed for 12 hours. The reaction is detected by thin-layer chromatography. After the reaction is completed, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase is then extracted with dichloromethane. The organic phases are combined and concentrated. The intermediate 6 (yield 81.9%) is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent.

[0115] Step 7 specifically includes the following steps: Under nitrogen atmosphere, intermediate 6 (1.0 eq) is dissolved in tetrahydrofuran at -70℃. Butyllithium (1.1 eq) is slowly added to the solution of intermediate 6 (1.0 eq). After reacting for 4 hours, triisopropyl borate solution is slowly added to the reaction flask. The mixture is then brought to room temperature and the reaction continues for 12 hours. The reaction is detected using thin-layer chromatography. After the reaction is complete, dilute hydrochloric acid is added, and a solid precipitates. The solid is then filtered to obtain intermediate 7 (yield 73.2%).

[0116] Step 8 specifically includes the following steps: Under nitrogen atmosphere, intermediates 5 and 7 are added to a mixed solution of toluene, ethanol and water. Palladium acetate (0.05 eq), X-Phos (0.01 eq), and cesium carbonate (2.0 eq) are added and stirred until homogeneous. The mixture is heated to 100°C and refluxed for 10 hours. The reaction is detected by thin-layer chromatography. After the reaction is complete, the temperature is slightly lowered, and the mixture is filtered with diatomaceous earth to remove salts and catalysts. The filtrate is cooled to room temperature, and the solvent is removed using a rotary evaporator. The remaining substances are purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=10:4) to obtain ligand La17 (yield 82.7%).

[0117]

[0118] Step 1 specifically includes the following steps: Under nitrogen atmosphere, ligand Lb80 (4.0 eq) (CAS No.: 92646-00-9) was added to a reaction vessel, followed by IrCl3·3H2O (1.0 eq), ethylene glycol ether, and water. The mixture was stirred until homogeneous, heated to 130°C, and reacted for 24 hours. The reaction was detected using thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed three times each with methanol and n-hexane, and dried at 60°C to obtain intermediate 8 (yield 62.9%).

[0119] Step 2 specifically includes the following steps: Under nitrogen atmosphere, intermediate 8 (1.0 eq) and silver trifluoromethanesulfonate (2.0 eq) are added to a mixed solution of isopropanol and DCM, stirred until homogeneous, and reacted at room temperature for 12 h. The reaction is detected by thin-layer chromatography. After the reaction is complete, the mixture is filtered with diatomaceous earth to remove salts and catalysts, washed three times with DCM, and the filtrate is collected. The solvent is removed using a rotary evaporator, and the filtrate is dried at 60 °C to obtain intermediate 9 (yield 71.4%).

[0120] Step 3 specifically includes the following steps: Under nitrogen atmosphere, intermediate 9 (1.0 eq) and La17 (1.5 eq) were added to ethanol, heated to 120°C, and reacted for 16 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, filtered with diatomaceous earth to remove salts and catalysts, and washed three times each with methanol and n-hexane. The resulting solid was dissolved in DCM, the organic phase was collected, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=10:4) to obtain organometallic compound 512 (yield 33.5%).

[0121] Characterization: The 1H NMR spectrum of organometallic compound 512 is shown in [reference needed]. Figure 2 .

[0122] HPLC purity: >99.95%.

[0123] Mass spectrometry test: The test value is 1146.42.

[0124] Elemental analysis: Test values ​​are: C, 63.67; H, 4.31; F, 10.08; N, 3.75; O, 1.51.

[0125] The synthesis methods for other organometallic compounds are the same as described above and will not be repeated here. This invention also provides an organic electroluminescent device, which is made from the above-mentioned organometallic compounds, more specifically, from organic light-emitting materials containing organometallic compounds with the structure of Formula I. To further describe this invention, more specific device embodiments are listed below.

[0126] Device Example 1: Fabrication of Green Organic Light Emitting Device a. ITO Anode: An ITO (Indium Tin Oxide)-Ag-ITO (Indium Tin Oxide) glass substrate with a coating thickness of 1500 Å was cleaned three times with distilled water and ultrasonically washed for 40 min. This was followed by three more cleansings with distilled water and ultrasonic washing for 20 min. After washing, the substrate was ultrasonically washed sequentially with methanol, acetone, and isopropanol (5 min each time), dried, and then transferred to a plasma cleaner for 5 min. Finally, it was sent to a vapor deposition machine, where other functional layers were sequentially deposited onto the substrate using it as the anode. The organic layers specified below were deposited under a vacuum of approximately 10... -8 In the case of T, the ITO anode is sequentially vaporized at a rate of 0.2-2 Å / s via thermal vacuum evaporation.

[0127] b. HIL (Hole Injection Layer): Hole injection layer materials HT-2 and HI-1 are vacuum-deposited at a deposition rate of 1 Å / s as the hole injection layer, wherein the deposition rate ratio of HT-2 and HI-1 is 97:3 and the thickness is 10 nm.

[0128] c. HTL (Hole Transport Layer): HT-2 of 130 nm was vacuum-deposited on the hole injection layer at a deposition rate of 1.5 Å / s as a hole transport layer.

[0129] d. EBL (Electron Blocking Layer): A hole blocking layer (EBM) with a thickness of 5 nm is vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s.

[0130] e. EML (Light Emitting Layer): A dual host material (Host-1 and Host-2) and a dopant material organometallic compound 11 with a thickness of 200 nm are vacuum-deposited on the light-emitting auxiliary layer at a deposition rate of 1 Å / s. The deposition rate ratio of the host material to the dopant material is 90:10, and the deposition rate ratio of Host-1 to Host-2 in the host material is 4:6. The chemical formulas of Host-1 and Host-2 are shown below.

[0131] f. HBL (hole blocking layer): A hole blocking layer HB-2 with a thickness of 5 nm is vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s.

[0132] g. ETL (Electron Transport Layer): ET-2 and 8-hydroxyquinoline-lithium (Liq) with a thickness of 30 nm are vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s, wherein the deposition rate ratio of ET-2 to Liq is 50:50.

[0133] h. EIL (Electron Injection Layer): An 8-hydroxyquinoline-lithium (Liq) film of 1.0 nm is vacuum-deposited on the electron transport layer at a deposition rate of 0.5 Å / s to form the electron injection layer.

[0134] i. Cathode: Aluminum was deposited at a deposition rate of 1 Å / s for 120 nm. The device was then transferred back to the glove box and encapsulated with a glass cover and desiccant to obtain the OLED device.

[0135] The structures of HT-2, HI-1, Host-1, Host-2, HB-1, ET-2, and EBM used in Embodiment 1 of the above devices are shown below:

[0136] Device Examples 2-53 Referring to the method of the above-described device embodiment 1, the only difference is that the doped material organometallic compound 11 is replaced with 9, 12, 15, 23, 27, 35, 38, 45, 48, 50, 62, 78, 117, 124, 126, 129, 131, 135, 138, 141, 150, 204, 210, 258, 263, 325, 385, 400, 430, 481, 486, 491, 494, 497, 500, 503, 520, 555, 605, 621, 625, 637, 655, 666, 682, 700, 725, 732, 748, 825, 858, and 942.

[0137] Device Comparison Examples 1-6 Organic electroluminescent devices were prepared according to the above-described method for preparing organic electroluminescent devices, except that the organometallic compound 11 in device example 1 was replaced with compounds a, b, c, d, e, and f, wherein the structural formulas of compounds a, b, c, d, e, and f are as follows:

[0138] Test Example 1 The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Examples 1-53 and Comparative Examples 1-6 were characterized at a brightness of 15000 nits. The test results are shown in Table 1 below.

[0139] Table 1. Results of luminous properties test (luminance value 15000 nits)

[0140]

[0141] As shown in Table 1, compared with the organic electroluminescent devices prepared by the comparative examples, the organic electroluminescent devices prepared by the organometallic compounds as phosphorescent doping materials provided in the embodiments of the present invention show a significant advantage in terms of device lifetime, which is improved by 9.9~20.0% compared with the comparative examples. At the same time, it also improves the driving voltage and luminous efficiency of the devices.

[0142] Test Example 2 This invention selects specific ligand compounds as shown in Formula 1 and attaches two or more identical or different fluorine, trifluoromethyl, or cyano-substituted biphenyls at sites R1-R4. By adjusting the intermolecular stereostructure and steric hindrance, the energy difference between the lowest excited singlet state energy level E(S1) and the lowest excited triplet state energy level E(T1) of the metal-coordinated compound can be effectively altered. The invention is fully validated using simulation methods employing Gaussian16, a program commonly used by those skilled in the art to predict the physical properties of designed organometallic complexes, at the B3LYP functional and mixed basis set (metal: LANL2DZ pseudopotential basis set, nonmetal 6-31G(d,p)) calculation levels, to perform density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations on the complexes.

[0143] The specific organometallic compounds are shown below, and the data are shown in Table 2. Table 2 shows that in Application Examples 1-7 of the present invention, when the same substituent changes at the ligand ends, a significant decrease in the dS1T1 gap is observed, suggesting that it possesses both phosphorescence and TADF luminescence mechanisms. In contrast, in Comparative Examples 1-3 of the prior art, the dS1T1 gap difference caused by the same substituent changes is minimal, maintaining only a single phosphorescence mechanism, thus forming a clear difference. Specifically, the organometallic compounds used in Application Examples 1-7 are compounds 962, 963, 964, 965, 966, 967, 968, 969, 970, 971, 972, 973, 974, and 975, as shown in the following structural formulas; the organometallic compounds used in Comparative Examples 1-3 are compounds g, h, i, j, k, and l, as shown in the following structural formulas.

[0144] Table 2. Changes in dST gap caused by naphthyl and cyanonaphthyl substitutions.

[0145] Table 3. Differences between dEST1 and dEST2 (reference)

[0146] In Table 3 above, dEST2 represents the dST gap of the complex formed by the ligand and the central metal, while dEST1 represents the dST gap when the ligand exists alone. The dST values ​​are the energy difference between the lowest excited singlet state level E(S1) and the lowest excited triplet state level E(T1) of the compound. Referring to the device fabrication method of Device Example 1, compounds 964 and 965 from Application Example 2 in Table 2 above, as well as compounds i and j from Comparative Application Example 2-, were used instead of compound 11 as doping materials to prepare a bottom-emitting device.

[0147] The four fabricated bottom-emitting devices were subjected to EL spectroscopy measurements. The test results are shown in [reference]. Figure 3 and Figure 4 .

[0148] according to Figure 3 The EL spectrum shows that the wavelength of compound 965 is shifted to a shorter wavelength by 10 nm compared to that of compound 964. This is because the change in the terminal substituent leads to a significant reduction in the dST band gap. Due to the TADF effect, S1 dominates the emission, causing compound 965 to shift to a shorter wavelength by 10 nm compared to compound 964.

[0149] according to Figure 4 It can be seen that, under the same substituent changes, the dST gap of compounds i and j changes little, which is 0.005 eV. Both compounds are dominated by T1 state emission. The wavelength of compound j is shifted by 12 nm towards longer wavelengths compared with the wavelength of compound i.

[0150] Test Example 3 The doped materials containing organometallic compounds with phosphorescence or TADF mechanisms provided in the embodiments of the present invention can be used as sensitizers in devices. The specific device fabrication method is as follows: EML (Emitting Layer): A bottom-emitting device was fabricated by vacuum evaporation of a 200 nm thick dual host material (Host-1 and Host-2), with phosphorescent dopant (organometallic compound 964) or TADF material (organometallic compound 965) as the sensitizer and green fluorescent dopant FGD1 as the emitting layer, at a deposition rate of 1 Å / s. The evaporation rate ratio of the host material to the sensitizer to the fluorescent dopant was 90:9:1, and the evaporation rate ratio of Host-1 to Host-2 in the host material was 4:6.

[0151] The green fluorescent dopant adopts the FGD1 structure, in which the phosphor encapsulation effect is introduced to minimize the Dexter energy transfer between various dopants known in the literature. The FGD1 structure is shown below;

[0152] For comparison, a bottom-emitting device was also fabricated using only the green fluorescent dopant FGD1, without any sensitizer. The main material was prepared using the same method, except that the evaporation rate of the fluorescent dopant was 99:1. EL spectroscopy and external quantum efficiency were measured on the fabricated devices; the results are shown below. Figure 5 See Table 4.

[0153] Table 4 Test Results

[0154] according to Figure 5 As shown in Table 4, the main peak of the EL spectrum of the AC device structure originates from the fluorescent dopant FGD1. This confirms that both organometallic compound 964 as a phosphorescent dopant and organometallic compound 965 as a TADF material can be used as sensitizers. When organometallic compound 965 is used as a sensitizer, it exhibits a shoulder peak in the long-wavelength region, confirming that organometallic compound 965, through the TADF phenomenon, not only acts as a sensitizer but also participates in partial luminescence as a phosphorescent dopant. Therefore, to develop more perfect TADF sensitizers, materials with better dST gap adjustment can be developed using the material design method of this invention.

[0155] The reason why device structure C has a higher external quantum efficiency than device structure B is due to the TADF effect. The EL spectrum of organometallic compound 965 is located at a shorter wavelength than that of organometallic compound 964, thus resulting in better spectral overlap with the fluorescence doping absorption spectrum.

[0156] In summary, the organometallic compounds provided in the embodiments of this invention can effectively utilize phosphorescence and TADF properties with a theoretical efficiency of 100%. When using the organometallic compounds of this invention in organic light-emitting devices, a significant advantage is observed in the lifetime of phosphorescent devices, confirmed to be 71 to 170 hours longer than comparative devices. Simultaneously, the luminous efficiency of superfluorescent devices utilizing TADF sensitizers is also improved.

[0157] Test Example 4 Devices were prepared using compounds with the structural formulas shown below, and the results were tested. The results are shown in Tables 5-14.

[0158]

[0159]

[0160]

[0161] Table 5. Structural Group 1 of the Examples: dsT gap = 0.177~0.349 eV

[0162] Table 6. Structural Group 2 of the embodiment: dsT gap = 0.108~0.357 eV

[0163] Table 7. Structural Group 3 of the embodiment: dsT gap = 0.081~0.347 eV

[0164] Table 8. Structural Group 4 of the Examples: dsT gap = 0.02~0.354 eV

[0165] Table 9. Structural Group 5 of the Examples: dsT gap = 0.177~0.369 eV

[0166] Table 10 shows the structure of Example Group 6: dsT gap = 0.032~0.347 eV.

[0167] Table 11. Structural Group 7 of the embodiment: dsT gap = 0.015~0.279eV

[0168] Table 12 Comparative example structures Group 1: dsT gap = 0.326~0.351 eV

[0169] Table 13 Comparative example structure Group 2: dsT gap = 0.352~0.367 eV

[0170] Table 14 Comparative example structure Group 3: dsT gap = 0.332~0.377eV

[0171] As shown in Tables 5-14 above, the dS1T1 gap of the organometallic compounds provided in the embodiments of the present invention is adjustable. In contrast, the dS1T1 gap of the comparative compounds changes less when the same substituents are adjusted. This indicates that the organometallic compounds provided in the embodiments of the present invention can function as both phosphorus photosensitizers and TADF sensitizers, while the comparative compounds can only function as phosphorus photosensitizers.

[0172] It should be noted that the above embodiments only list the effect data of devices made from a portion of the structures. This is a representative sampling test. Based on the experimental data, the overall data is not significantly different and can represent the effects of other unlisted structures.

[0173] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An organometallic compound, characterized in that, The organometallic compound or organometallic complex has a structural formula selected from any one of the compounds shown in the following structural formulas: 。 2. An organic light-emitting layer material, characterized in that, It includes a host material and a TADF material; the TADF material can be selected from the organometallic compounds shown in claim 1.

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