Organometallic compound and organic electroluminescent device containing same

Abstract

The invention relates to the technical field of organic photoelectric materials, and provides an organic metal compound and an organic electroluminescent device containing the same. The organic metal compound has a structure represented by Ir (La) m (Lb) n (Lc) s. The organic electroluminescent device prepared from the organic metal compound has the technical effects of high luminous efficiency, long service life and low driving voltage.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials technology, specifically to an organometallic compound and an organic electroluminescent device containing the same. Background Technology

[0002] Organic light-emitting diodes (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. The color of OLED emission 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 lifetime when phosphorescent materials are used in organic light-emitting devices.

[0003] 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 with the host material and the fluorescent emitter material to form the emitting layer. When electrons and holes recombine in the host material to form excitons, these excitons first transfer energy to the TADF material. Through the antisystem crossing capability of TADF, electrons in 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), and finally, the conventional fluorescent material emits fluorescence, also 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 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 significant room for improvement in meeting the above requirements of existing TADF materials, and the industry urgently needs to develop new sensitized fluorescent OLED materials.

[0004] 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. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide organometallic compounds and organic light-emitting layer materials. Embodiments of the present invention provide a novel organometallic compound, which, when used in an organic electroluminescent device, enables the organic electroluminescent device to possess the characteristics of long lifetime, high efficiency, and low driving voltage.

[0006] This invention provides an organometallic compound having a structure of Formula I, wherein Formula I has the structure shown in Ir(La)m(Lb)n(Lc)s;

[0007] Among them, La, Lb and Lc can be optionally linked together to form a polydentate ligand; Among them, La has The structure shown has Lb with The structure shown, Lc has Lc-1 or The structure shown in Lc-2; m+n+s=3; m is 1 or 2, n is 1 or 2, and s is 0 or 1; When m is 2 and n is 1, s is 0; When m is 1 and n is 2, s is 0; When m is 1 and n is 1, s is 1; q is an integer selected from 0 to 3; r is an integer selected from 0 to 4; p is an integer selected from 0 to 3; R and R' each have one and only one substituent selected from those other than hydrogen and deuterium; R and R' are each independently selected from: hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group, substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanyl, substituted or unsubstituted C6-C30 aryl, and combinations of the above groups; Ra and Re may be the same or different, and each is independently selected from: hydrogen, deuterium, -CN, halogen, -TMS, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group; substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanium, substituted or unsubstituted C6-C30 aryl; and combinations of the above groups; Rb and Rc may be the same or different, and each is independently selected from: substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group; substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanyl, substituted or unsubstituted C6-C30 aryl; and combinations of the above groups; Rd is selected from hydrogen or deuterium; R1, R2, R3, and R4 may be the same or different, and each may be independently selected from: hydrogen, deuterium, -CN, halogen, TMS, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group; substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanium, substituted or unsubstituted C6-C30 aryl, and combinations of the above groups; The term "substituted or unsubstituted" means that the group may not be substituted, or may be substituted by one or more substituents. "Substitution" means that the hydrogen atom bonded to the carbon atom of the compound becomes another substituent, and there is no restriction on the position of substitution, as long as the position is where the hydrogen atom is substituted, i.e., the position where the substituent can be substituted. When two or more substituents are substituted, the two or more substituents may be the same as or different from each other.

[0008] Heterocyclic groups include monocyclic aromatic groups and polycyclic aromatic ring systems with at least one heteroatom, where the heteroatom is O, S, or N.

[0009] "Substituted or unsubstituted" means substituted with one, two or more of the following substituents: deuterium; halogen group; -CD3, -CN; -TMS, methyl, ethyl, propyl, butyl, pentyl, hexyl, C7-C15 alkyl; C3-C20 cycloalkyl; alkoxy; C6-C30 aryl; C3-C30 heterocyclic, or substituted with two or more of the substituents shown above linked together, or without substituents.

[0010] Furthermore, Equation I is selected from the structures Ia to Id: ; R is selected from hydrogen, deuterium, or C1-C15 alkyl groups that are substituted with or unsubstituted with deuterium; R' is selected from hydrogen, deuterium, or C1-C15 alkyl groups that are substituted with or unsubstituted with deuterium; And the total number of alkyl groups in R and R' is 1; Rb and Rc are each independently selected from: C1-C15 alkyl groups that are substituted with deuterium or unsubstituted; Ra, R1-R4, and Re are each independently selected from: hydrogen, deuterium, -CN, halogen, -TMS, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C3-C15 cycloalkyl, substituted or unsubstituted C6-C24 aryl, and heterocyclic groups with substituted or unsubstituted C3-C24 ring atoms. p, q, and r are each independently selected from 0 or 1.

[0011] In this invention, the phrase "the total number of alkyl groups in R and R' is 1" refers to the central Ir metal of compounds with the Ir(La)m(Lb)n(Lc)s structure being directly bonded. The total number of alkyl groups that are substituted is 1, i.e., q+r=1; "substituted with deuterium" means that at least one hydrogen in the group is recoordinated with deuterium.

[0012] Going further, R and R' are each independently selected from hydrogen, deuterium, and the following groups that are substituted or unsubstituted by deuterium: methyl, ethyl, propyl, butyl, pentyl, hexyl; and the total number of alkyl groups in R and R' is 1. Re, Ra, and R1-R4 are each independently selected from hydrogen, deuterium, -CN, -F, -TMS, and the following groups substituted or unsubstituted with deuterium: methyl, ethyl, propyl, butyl, pentyl, hexyl; and the following groups substituted or unsubstituted: phenyl, biphenyl, naphthyl, diphenylfluorenyl, dimethylfluorenyl, thienyl, furanyl, dibenzothienyl, dibenzofuranyl, phenanthryl, anthraceneyl, pyrene, perylene.

[0013] Furthermore, R and R' are each independently selected from hydrogen, deuterium, CHD2, CH2D, CH3, CD3, and the following groups: ; Re, Ra, and R1-R4 are each independently selected from hydrogen, deuterium, -CN, -F, -TMS, CHD2, CH2D, CH3, CD3, and the following groups: .

[0014] Specifically, Equation I is selected from the following structure, but is not limited to this:

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042] .

[0043] The present invention also provides an organic electroluminescent device, the organic electroluminescent device comprising an organic layer; the organic layer containing an organometallic compound as described above.

[0044] Furthermore, the organic electroluminescent device further includes a first electrode and a second electrode; the organic layer is disposed between the first electrode and the second electrode; wherein, The organic layer includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; the light-emitting layer contains the aforementioned organometallic compound.

[0045] Furthermore, the light-emitting layer comprises a host material and a phosphorescent dopant material and / or a TADF material; the phosphorescent dopant material and the TADF material are selected from the aforementioned organometallic compounds.

[0046] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: The present invention provides an organometallic compound and an organic electroluminescent device comprising the organometallic compound having the structure shown in Ir(La)m(Lb)n(Lc)s; Among them, the La ligand has The phenyl group has R' and a phenyl group substituted with Rb or Rc; the Lb ligand has The compounds are substituted with deuterium, cyano, and R. The total number of alkyl groups in R and R' on La and Lb is 1. The organometallic compounds can be used as phosphorescent dopant, TADF material, and sensitizer. Organic electroluminescent devices prepared using these compounds have the technical advantages of high luminous efficiency, long lifetime, and low driving voltage. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0048] Figure 1 This is the 1H NMR spectrum of compound 141 of the present invention. Detailed Implementation

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] The present invention discloses a method for preparing organometallic compounds and an organic electroluminescent device containing the same.

[0051] Additionally, it should be noted that the values ​​given in the following embodiments are as accurate as possible. However, those skilled in the art will understand that due to unavoidable measurement errors and experimental issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0052] Synthesis Example 1: Synthesis of Compound 141

[0053]

[0054]

[0055] CAS: Reactant 141-a:372963-49-0 CAS: Reactant 141-b:3065449-61-5 CAS: Reactant 141-d: 2170167-49-2 CAS: Reactant 141-e: 325141-72-8 Step (1): Reactant 141-a (1.0 eq), reactant 141-b (1.2 eq), toluene, water, and anhydrous ethanol were added to the reaction system. Nitrogen gas was replaced twice. Tetra(triphenylphosphine)palladium (Pd(PPh3)4) (0.01 eq) and potassium carbonate (K2CO3) (2.0 eq) were added to the reaction system under nitrogen protection. The mixture was heated to 90 °C and stirred for 16 hours. The reaction was monitored by TLC until it was complete. The reaction system was cooled to 25 °C, and the mixture was separated. The organic phase was extracted and dried with anhydrous sodium sulfate. The organic phase was distilled under reduced pressure until no liquid flowed out. The distilled solid was purified by column chromatography (eethyl acetate: petroleum ether = 1:30) to obtain intermediate 141-c (yield 66.8%).

[0056] Step (2): Reactant 141-d (1.0 eq), reactant 141-e (1.2 eq), toluene, water, and anhydrous ethanol were added to the reaction system. Nitrogen gas was replaced twice. Under nitrogen protection, Pd(PPh3)4 (0.015 eq) and K2CO3 (1.8 eq) were added to the reaction system. The mixture was heated to 90°C and stirred for 16 hours. The reaction was monitored by TLC until it was complete. The reaction system was cooled to 25°C, and the mixture was separated. The organic phase was extracted and dried with anhydrous sodium sulfate. The organic phase was distilled under reduced pressure until no liquid flowed out. The distilled solid was purified by column chromatography (eethyl acetate: petroleum ether = 1:30) to obtain intermediate 141-f (yield 72.6%).

[0057] Step (3): Under nitrogen protection, weigh intermediate 141-c (3.0 eq) and iridium trichloride trihydrate (IrCl·3H2O) (1.0 eq) and add them to the reaction system. Add a mixed solution of ethylene glycol ethyl ether and purified water. Stir at 120°C for 48 hours under nitrogen protection. Then, cool the reaction system to 30°C. A precipitate will form in the solution. Filter the precipitate under reduced pressure and wash it with water, anhydrous ethanol and petroleum ether in sequence. Dry the obtained solid to obtain intermediate 141-g (yield 64.3%).

[0058] Step (4): Weigh 141-g (1.0 eq) of intermediate, add silver trifluoromethanesulfonate (2.5 eq), then add dichloromethane and methanol to the system. Under nitrogen protection, stir at 25°C for 56 hours. After the reaction is complete, distill the reaction solution until no liquid flows out, perform column chromatography (developing solvent: dichloromethane), and distill the receiving solution under reduced pressure until no solid precipitates, to obtain intermediate 141-h (yield 82.5%).

[0059] Step (5): Weigh intermediate 141-h (1.0 eq), add intermediate 141-f (3.0 eq), and add anhydrous ethanol to the system. Under nitrogen protection, reflux at 90°C for 24 hours. After the reaction is complete, lower the temperature of the reaction system to 25°C, filter the solution under reduced pressure, wash the filter cake with anhydrous ethanol and petroleum ether in sequence, and dry it under vacuum at 80°C. After drying, perform solid silica gel column chromatography (developing solvent: dichloromethane), concentrate the filtrate to precipitate the solid, and obtain compound 141 (yield 37.2%).

[0060] Characterization: Mass spectrometry measured value MS (ESI, m / Z): [M+H]+=1047.56 The proton NMR spectrum of compound 141 is as follows: Figure 1 As shown.

[0061] HPLC purity: >99.6%.

[0062] Synthesis Example 2: Synthesis of Compound 326

[0063]

[0064]

[0065] CAS: Reactant 326-a:2565788-34-1 CAS: Reactant 326-b:3083254-84-3 CAS: Reactant 326-d: 2214249-51-9 CAS: Reactant 326-e: 325141-72-8 Step (1): Reactant 326-a (1.0 eq), reactant 326-b (1.2 eq), toluene, water, and anhydrous ethanol were added to the reaction system. Nitrogen gas was purged twice. Tetra(triphenylphosphine)palladium (Pd(PPh3)4) (0.01 eq) and potassium carbonate (K2CO3) (2.0 eq) were added to the reaction system under nitrogen protection. The mixture was heated to 90°C and stirred for 16 hours. The reaction was monitored by TLC until it was complete. The reaction system was cooled to 25°C, and the mixture was separated. The organic phase was extracted and dried with anhydrous sodium sulfate. The organic phase was distilled under reduced pressure until no liquid flowed out. The distilled solid was purified by column chromatography (eethyl acetate: petroleum ether = 1:30) to obtain intermediate 326-c (yield 61.4%).

[0066] Step (2): Add reactant 326-d (1.0 eq), reactant 326-e (1.2 eq), toluene, water, and anhydrous ethanol to the reaction system, replace with nitrogen twice, add Pd(PPh3)4 (0.015 eq) and K2CO3 (1.8 eq) to the reaction system under nitrogen protection, heat to 90°C, stir for 16 hours, monitor the reaction for completeness by TLC, cool the reaction system to 25°C, separate the liquid and extract the organic phase, dry the organic phase with anhydrous sodium sulfate, distill the organic phase under reduced pressure until no liquid flows out, purify the distilled solid by column chromatography (eethyl acetate: petroleum ether = 1:30) to obtain intermediate 326-f (yield 79.5%).

[0067] Step (3): Under nitrogen protection, weigh intermediate 326-f (3.0 eq) and iridium trichloride trihydrate (IrCl·3H2O) (1.0 eq) and add them to the reaction system. Add a mixed solution of ethylene glycol ethyl ether and purified water. Stir at 120°C for 48 hours under nitrogen protection. Then, cool the reaction system to 30°C. A precipitate will form in the solution. Filter the precipitate under reduced pressure and wash it with water, anhydrous ethanol and petroleum ether in sequence. Dry the obtained solid to obtain intermediate 326-g (yield 60.2%).

[0068] Step (4): Weigh 326-g (1.0 eq) of intermediate, add silver trifluoromethanesulfonate (2.5 eq), then add dichloromethane and methanol to the system. Under nitrogen protection, stir at 25°C for 56 hours. After the reaction is complete, distill the reaction solution until no liquid flows out, perform column chromatography (developing solvent: dichloromethane), and distill the receiving solution under reduced pressure until no solid precipitates, to obtain intermediate 326-h (yield 76.8%).

[0069] Step (5): Weigh intermediate 326-h (1.0 eq), add intermediate 326-c (3.0 eq), and then add anhydrous ethanol to the system. Under nitrogen protection, reflux at 90°C for 24 hours. After the reaction is complete, lower the temperature of the reaction system to 25°C, filter the solution under reduced pressure, and wash the filter cake with anhydrous ethanol and petroleum ether in sequence. Dry it under vacuum at 80°C. After drying, perform solid silica gel column chromatography (developing solvent: dichloromethane). Concentrate the filtrate to precipitate the solid and obtain compound 326 (yield 40.4%).

[0070] Characterization: Mass spectrometry measured MS (ESI, m / Z): [M+H]+=1235.64 HPLC purity: >99.6%.

[0071] 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.

[0072] This invention provides 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. The organic material layer includes at least one of the layered structures formed by organometallic compounds as described above.

[0073] This invention provides an organic light-emitting layer material, which includes a host material and a phosphorescent dopant material and / or a TADF material; the phosphorescent dopant material and the TADF material are selected from organometallic compounds of formula I.

[0074] The main materials include aromatic fused-ring derivatives or heterocyclic compounds. Specifically, aromatic fused-ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentane derivatives, phenanthrene compounds, and fluoranthene compounds; heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, and pyrimidine derivatives.

[0075] Furthermore, the organic material layer further includes at least one of a hole injection layer, a light-emitting auxiliary layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, or an electron injection layer. Specifically, the organic electroluminescent device includes an anode, a hole injection layer, a light-emitting auxiliary layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode arranged sequentially.

[0076] 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.

[0077] 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.

[0078] 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).

[0079] Hole transport materials are materials capable of receiving holes from the anode or hole injection layer and transporting them to the light-emitting layer; they are materials with high hole mobility. Hole transport materials can be selected from aryl amine derivatives, conductive polymers, and block copolymers containing both conjugated and non-conjugated parts.

[0080] An auxiliary light-emitting layer (multilayer hole transport layer) is added between the hole transport layer and the light-emitting layer. The auxiliary light-emitting layer primarily assists the hole transport layer and is therefore sometimes referred to as a second hole transport layer. This layer allows holes transferred from the anode to smoothly move to the light-emitting layer and blocks electrons transferred from the cathode, confining them within the light-emitting layer. This reduces the potential barrier between the hole transport layer and the light-emitting layer, lowers the driving voltage of the organic light-emitting device, and further increases hole utilization, thereby improving the device's luminous efficiency and lifetime.

[0081] 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 including but not limited to compounds shown below HT-1 to HT-27, or any combination thereof.

[0082]

[0083]

[0084] 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 from HT-1 to HT-27 described above, or one or more compounds from HI-1 to HI-3 described below; it can also be doped with one or more compounds from HT-1 to HT-27, but is not limited thereto.

[0085]

[0086] 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).

[0087] An electron transport layer can facilitate electron transport. The electron transport material is one that advantageously receives electrons from the cathode and transports them to the light-emitting layer, preferably a material with high electron mobility. The electron transport layer may include at least one of an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer, and preferably at least one of an electron transport layer and an electron injection layer.

[0088] 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.

[0089]

[0090]

[0091] The electron injection layer can promote electron injection and prevent excitons generated in the light-emitting layer from migrating to the hole injection layer. Materials for the electron injection layer include, but are not limited to, oxazoles, oxadiazoles, triazoles, imidazoles, perylenetetracarboxylic acids, fluorenemethane, anthrones and their derivatives, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, ytterbium, or their alloys, metal complexes, or nitrogen-containing 5-membered ring derivatives.

[0092] The cathode is typically made of a material with a low work function to facilitate electron injection into the organic material layer, the thickness of which is preferably between 0.5 and 5 nm. The cathode material is generally preferred to have a low work function in order to facilitate electron injection into the organic layer. Specific examples of cathode materials include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or their alloys; among which, alloys are selected from multilayer structures such as LiF / Al or LiO2 / Al, Mg / Ag, etc.

[0093] Apart from the doping materials disclosed herein and the TADF material being selected from organometallic compounds of Formula I, there are no special restrictions on other layer materials in OLED devices.

[0094] The following detailed description, in conjunction with specific embodiments, illustrates an organic electroluminescent compound and an organic electroluminescent device provided by the present invention.

[0095] I. Compounds of Formula I are used as doping materials in green organic light-emitting devices. The embodiments of the present invention can be used as doping materials in devices, and the specific device fabrication method is as follows: a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm is cleaned twice in distilled water, ultrasonically washed for 30 minutes, then repeatedly cleaned twice in distilled water, ultrasonically washed for 10 minutes, and baked in a vacuum oven at 220℃ for 2 hours. After baking, it can be used after cooling. Using this substrate as the anode, the device process is carried out by vapor deposition machine, and other functional layers are sequentially vapor deposited on it. b. HIL (Hole Injection Layer): Hole injection layer materials HT and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s, and their chemical formulas are shown below; the deposition rate ratio of HT and P-dopant is 95:5, and the thickness is 10 nm. c. HTL (Hole Transport Layer): A 130 nm HT layer is vacuum-deposited on the hole injection layer at a deposition rate of 1.0 Å / s as a hole transport layer. d. Prime (light-emitting auxiliary layer): A 40 nm prime layer is vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a light-emitting auxiliary layer; e. EML (Light Emitting Layer): On the light-emitting auxiliary layer, a host material (GH-1+GH-2) with a total thickness of 30 nm is vacuum-deposited at a deposition rate of 1 Å / s, and Formula I of the present invention is used as the light-emitting layer doping material. GH-1 and GH-2 are co-deposited as dual host materials and doping materials, with a ratio of GH-1 to GH-2 of 50%:50%, and a deposition rate ratio of host material to Formula I of 90:10. f. HBL (hole blocking layer): A hole blocking layer with a thickness of 5.0 nm is vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s. g. ETL (Electron Transport Layer): ET and Liq with a thickness of 30 nm are vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s as an electron transport layer; the deposition rate ratio of ET to Liq is 50:50. h. EIL (Electron Injection Layer): A 1.0 nm Yb film is deposited on the electron transport layer at a deposition rate of 0.5 Å / s to form the electron injection layer; i. Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s for 13 nm, with a deposition rate ratio of 1:9, to form the cathode; j. Optical extraction layer: A CPL with a thickness of 70 nm is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer. k. Encapsulate the vapor-deposited substrate; First, use a coating equipment to coat the cleaned cover plate with UV adhesive. Then, move the coated cover plate to the pressing section, place the vapor-deposited substrate on the top of the cover plate, and finally bond the substrate and cover plate together under the action of the bonding equipment, while simultaneously completing the UV adhesive photocuring.

[0096] The material structures involved in device fabrication are as follows: .

[0097] Application Examples 1-111 Organic electroluminescent devices of Application Examples 1-111 were prepared according to the above-described method for preparing organic electroluminescent devices, except that the compounds in Formula I were replaced with the corresponding compounds in Table 1.

[0098] Comparative Application Example 1-Comparative Application Example 12 Organic electroluminescent devices are prepared according to the above-described method, except that the compounds in Formula I are replaced with comparative compounds 1-12 respectively.

[0099] The structures of the substances involved in comparative compounds 1-12 are as follows: .

[0100] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Application Examples 1-111 and Comparative Application Examples 1-12 were tested at a brightness of 15000 nits under T97. The test results are shown in Table 1 below.

[0101] Table 1. Results of luminous properties test (luminance value 15000 nits)

[0102] As can be seen from Table 1 above, the compound shown in Formula I, as a doping material, exhibits higher luminous efficiency and longer lifetime in Application Examples 1 to 111 than in the comparative examples.

[0103] At a brightness of 15000 nits, the luminous efficiency of the compound of the present invention is 175-185.5 cd / A, while that of the comparative compound is 161-164 A. The lifetime of the compound of the present invention is 1060-1130 h, while that of the comparative compound is 898-930 h, representing an improvement of 13.9-28.4%. It is evident that the compound of the present invention has achieved significant improvements in luminous efficiency and lifetime compared to the prior art.

[0104] II. Compound of Formula I is used as a sensitizer in green organic light-emitting diodes. The embodiments of the present invention can be used as sensitizers in devices. The specific device fabrication method is as follows: The fabrication method is the same as that used in Application Example 1-111 above, except that the light-emitting layer is fabricated in the following manner: e. EML (Light Emitting Layer): On the light emitting auxiliary layer, a host material ((GH-1+GH-2), a fluorescent dopant (FGD1), and a sensitizer (Formula I of this invention) with a total thickness of 30 nm are vacuum-deposited at a deposition rate of 1 Å / s. The deposition rate ratio of GH-1 to GH-2 is 4:6, and the deposition rate ratio of the host material, the sensitizer (Formula I), and the fluorescent dopant is 90:9:1. The structure of the fluorescent doped material (FGD1) is as follows:

[0105] The comparative compounds used are as follows:

[0106] Under a 15000 nit brightness test condition, the driving voltage, luminous efficiency, and lifetime T97 of the organic electroluminescent device obtained from Application Case 112-Application Example 138 and Comparative Application Example 13-Application Comparative Example 15 were characterized, and the test results are shown in Table 2.

[0107] Table 2

[0108] As can be seen from Table 2 above, the compounds shown in Formula I, as sensitizers, exhibited longer lifespans in Application Examples 112 to 138.

[0109] At a brightness of 15000 nits, the luminous efficiency of the compound of the present invention is 174.1-182.9 cd / A, while that of the comparative compound is 159.3-160.8 cd / A. The lifetime of the compound of the present invention is 1281-1350 h, while that of the comparative compound is 952-970 h, representing a lifetime improvement of 36.4-51.1%. It is evident that the compound of the present invention, as a sensitizer, has achieved a significant improvement, especially in extending the device lifetime.

[0110] The present invention provides an organometallic compound and an organic electroluminescent device comprising the organometallic compound having the structure shown in Ir(La)m(Lb)n(Lc)s; Among them, the La ligand has The phenyl group has R' and a phenyl group substituted with Rb or Rc; the Lb ligand has The compounds are substituted with deuterium, cyano, and R. The total number of alkyl groups in R and R' on La and Lb is 1. The organometallic compounds can be used as phosphorescent dopant, TADF material, and sensitizer. Organic electroluminescent devices prepared using these compounds have the technical advantages of high luminous efficiency, long lifetime, and low driving voltage.

[0111] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organometallic compound, characterized in that, It has the structure shown by Ir(La)m(Lb)n(Lc)s; La, Lb, and Lc can be optionally linked together to form a polydentate ligand; Among them, La has The structure shown has Lb with The structure shown has Lc-1 or Lc-2 The structure shown; m+n+s=3; m is 1 or 2, n is 1 or 2, and s is 0 or 1; When m is 2 and n is 1, s is 0; When m is 1 and n is 2, s is 0; When m is 1 and n is 1, s is 1; q is an integer selected from 0 to 3; r is an integer selected from 0 to 4; p is an integer selected from 0 to 3; R and R' each have one and only one substituent selected from those other than hydrogen and deuterium; R and R' are each independently selected from: hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group, substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanyl, substituted or unsubstituted C6-C30 aryl, and combinations of the above groups; Ra and Re may be the same or different, and each is independently selected from: hydrogen, deuterium, -CN, halogen, -TMS, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group; substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanium, substituted or unsubstituted C6-C30 aryl; and combinations of the above groups; Rb and Rc may be the same or different, and each is independently selected from: substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group; substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanyl, substituted or unsubstituted C6-C30 aryl; and combinations of the above groups; Rd is selected from hydrogen or deuterium; R1, R2, R3, and R4 may be the same or different, and each may be independently selected from: hydrogen, deuterium, -CN, halogen, TMS, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C30 heterocyclic group; substituted or unsubstituted C3-C20 alkylsilyl, substituted or unsubstituted C3-C20 alkylgermanium, substituted or unsubstituted C6-C30 aryl, and combinations of the above groups; Heterocyclic groups include monocyclic aromatic groups and polycyclic aromatic ring systems with at least one heteroatom, where the heteroatom is O, S, or N. "Substituted or unsubstituted" means substituted with one, two or more substituents selected from the following: deuterium; halogen group; -CD3, -CN; -TMS, methyl, ethyl, propyl, butyl, pentyl, hexyl, C7-C15 alkyl; C3-C20 cycloalkyl; alkoxy; C6-C30 aryl; C3-C30 heterocyclic, or substituted with two or more substituents linked together from the substituents shown above, or without substituents.

2. The organometallic compound according to claim 1, characterized in that, The organometallic compounds are selected from structures Ia to Id: ； R is selected from hydrogen, deuterium, or C1-C15 alkyl groups that are substituted with or unsubstituted with deuterium; R' is selected from hydrogen, deuterium, or C1-C15 alkyl groups that are substituted with or unsubstituted with deuterium; Furthermore, the total number of alkyl groups in R and R' is 1, meaning that the central Ir metal in compounds with the Ir(La)m(Lb)n(Lc)s structure is directly bonded. The total number of alkyl groups substituted is 1, i.e., q+r=1; Rb and Rc are each independently selected from: C1-C15 alkyl groups that are substituted with deuterium or unsubstituted; Ra, R1-R4, and Re are each independently selected from: hydrogen, deuterium, -CN, halogen, -TMS, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C3-C15 cycloalkyl, substituted or unsubstituted C6-C24 aryl, and heterocyclic groups with substituted or unsubstituted C3-C24 ring atoms. p, q, and r are each independently selected from 0 or 1.

3. The organometallic compound according to claim 2, characterized in that, R and R' are each independently selected from hydrogen, deuterium, and the following groups that are substituted or unsubstituted by deuterium: methyl, ethyl, propyl, butyl, pentyl, hexyl; and the total number of alkyl groups in R and R' is 1. Re, Ra, and R1-R4 are each independently selected from hydrogen, deuterium, -CN, -F, -TMS, and the following groups substituted or unsubstituted with deuterium: methyl, ethyl, propyl, butyl, pentyl, hexyl; and the following groups substituted or unsubstituted: phenyl, biphenyl, naphthyl, diphenylfluorenyl, dimethylfluorenyl, thienyl, furanyl, dibenzothienyl, dibenzofuranyl, phenanthryl, anthraceneyl, pyrene, perylene.

4. The organometallic compound according to claim 3, characterized in that, R and R' are each independently selected from hydrogen, deuterium, CHD2, CH2D, CH3, CD3, and the following groups: ； Re, Ra, and R1-R4 are each independently selected from hydrogen, deuterium, -CN, -F, -TMS, CHD2, CH2D, CH3, CD3, and the following groups: 。 5. The organometallic compound according to claim 1, characterized in that, The organometallic compound is selected from any one of the compounds shown in the following structural formulas: 。 6. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an organic layer; the organic layer contains the organometallic compound as described in claim 1.

7. The organic electroluminescent device according to claim 6, characterized in that, The organic electroluminescent device further includes a first electrode and a second electrode; the organic layer is disposed between the first electrode and the second electrode; wherein... The organic layer includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; the light-emitting layer contains the aforementioned organometallic compound.

8. The organic electroluminescent device according to claim 7, characterized in that, The light-emitting layer comprises a host material and a phosphorescent dopant material and / or a TADF material; the phosphorescent dopant material and the TADF material are selected from the aforementioned organometallic compounds.

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