CN107236006B

CN107236006B - Red light metal complex and organic electroluminescent device thereof

Info

Publication number: CN107236006B
Application number: CN201710555680.7A
Authority: CN
Inventors: 张保华; 刘雪景; 谢志元; 吴江
Original assignee: Changchun Institute of Applied Chemistry of CAS
Current assignee: Changchun Institute of Applied Chemistry of CAS
Priority date: 2017-07-10
Filing date: 2017-07-10
Publication date: 2020-08-25
Anticipated expiration: 2037-07-10
Also published as: CN107236006A

Abstract

The invention provides red light shown in formula (I)Metal complexes: wherein m is 2, n is 1 or m is 3, n is 0; r₁Independently selected from C1-C10 alkyl, C1-C10 substituted alkyl and C6-C10 aryl; r₂Independently selected from C1-C10 alkyl, C6-C25 aryl and C6-C25 heterocyclic aryl; ar is C6-C30 heterocyclic aryl. According to the invention, the aromatic group is connected with fluorene as a main group, and triphenylamine is used as an end-capping group, so that the interaction force between dye molecules is reduced due to the synergistic effect of the aromatic group and the triphenylamine and the steric hindrance effect of the triphenylamine, the self-quenching phenomenon of triplet excitons in a solid film is reduced, and simultaneously, the strong electron-donating effect of the triphenylamine effectively raises the HOMO energy level, thereby reducing the band gap and realizing red shift of the spectrum. The red to deep red phosphorescent iridium complex prepared by the method has good solubility in common solvents, is beneficial to preparing solution processing type devices, and the prepared organic electroluminescent device has high luminous efficiency and power efficiency.

Description

Red light metal complex and organic electroluminescent device thereof

Technical Field

The invention relates to the technical field of organic electroluminescence, in particular to a red light metal complex and an organic electroluminescent device thereof.

Background

Organic Light-Emitting Diodes (OLEDs) are driven by low-voltage direct current, have low energy consumption, are easy to realize large-area flexible display, actively emit Light, have high response speed, low cost, and the like, are widely concerned by academia and industry, have been successfully industrialized in part of products at present, and are considered as the most potential next-generation display and lighting technologies.

Organic electroluminescent materials can be classified into two major categories, i.e., fluorescent and phosphorescent, according to the principle of light emission. Since the phosphorescent material can simultaneously utilize singlet and triplet excitons, the internal quantum efficiency of the device can theoretically reach 100%. Therefore, the transition metal complex is widely applied to the preparation of high-efficiency organic electroluminescent devices. Among them, the iridium complex is particularly important because it has a suitable triplet lifetime and high luminous efficiency, and can realize luminescence of different wavelengths by the adjustment of the first and second ligands.

Due to the limitation of the energy law, that is, the luminous efficiency of the organic light emitting material decreases with the red shift of the spectrum, it is a big difficulty to design and synthesize a red phosphorescent material with high efficiency and high color purity compared with other colors. In addition, the host material with a wide band gap and the red dye guest with a narrow band gap have large difference in HOMO and LUMO energy levels, so that the guest material in the light emitting layer acts as a deep trap for electrons or holes, and the working voltage of the device is remarkably increased. Also self-quenching and triplet-triplet annihilation of phosphorescent dyes in host-guest systems, especially at high doping concentrations, is a problem to be solved.

Chinese patents ZL200710055980.5, ZL200510017140.0 and ZL200710055932.6 disclose red and green metal complexes with carbazole units as dendrons. The carbazole branches have good hole transport capacity and can wrap the central luminous core, so that the phosphorescent material is very suitable for preparing efficient solution-processed doped and undoped devices. The luminous efficiency of the electroluminescent device made of the dendritic phosphorescent material taking the green light metal iridium complex as the luminous core can reach 53.2 cd/A; but the efficiency of the electroluminescent device taking the red-light metal iridium complex as the luminescent core only reaches 13.2 cd/A.

Disclosure of Invention

In view of the above, the present invention provides a red light (including red light to deep red light) metal complex, and an organic electroluminescent device prepared from the red light metal complex has high luminous efficiency and power efficiency.

The invention provides a red light metal complex shown as a formula (I):

wherein m is 2, n is 1 or m is 3, n is 0;

R₁independently selected from C1-C10 alkyl, C1-C10 substituted alkyl and C6-C10 aryl; r₂Independently selected from C1-C10 alkyl, C6-C25 aryl and C6-C25 heterocyclic aryl; ar is C6-C30 heterocyclic aryl.

Preferably, said R is₁Independently selected from C1-C5 alkyl, C1-C5 substituted alkyl and C6-C10 aryl; said substituted alkylThe substituent of the group is halogen; the R is₂Independently selected from C1-C5 alkyl, C6-C22 substituted or unsubstituted aryl, C6-C22 substituted or unsubstituted heterocyclic aryl; the heteroatom of the heterocyclic aryl group is O, S or N.

Preferably, said R is₁Independently selected from methyl, trifluoromethyl, tert-butyl or phenyl;

the R is₂Independently selected from C1-C5 alkyl, C6-C20 substituted or unsubstituted aryl, C6-C20 substituted or unsubstituted heterocyclic aryl; the heteroatom of the heterocyclic aryl group is O, S or N; the substituent of the substituted aryl is one or more of halogen, cyano, alkyl, alkoxy, ester group, amino, borate group, acyl, acylamino, aryloxy or heterocyclic group; the substituent of the substituted heterocyclic aryl is one or more of halogen, cyano, alkyl, alkoxy, ester group, amino, borate group, acyl, acylamino, aryloxy or heterocyclic group.

Preferably, Ar is C6-C20 heterocyclic aryl; the heteroatom of the heterocyclic aryl group is O, S or N.

Preferably, Ar is a structure represented by formula (a-1) to formula (a-8):

preferably, the compound of formula (I) has the following structure:

the invention provides a preparation method of a red light metal complex shown as a formula (I), which comprises the following steps:

reacting the compound with the structure of the formula (II) with iridium chloride trihydrate to obtain an intermediate;

reacting the intermediate with acetylacetone to obtain a red light metal complex shown in a formula (I);

or

reacting the intermediate with a compound with a structure shown in a formula (II) to obtain a red light metal complex shown in the formula (I);

wherein R is₂Independently selected from C1-C10 alkyl, C6-C25 aryl and C6-C25 heterocyclic aryl; ar is C6-C30 heterocyclic aryl.

Preferably, the compound of formula (II) is prepared by the following method:

reacting a compound with a structure shown in a formula (III) with 4-halo triphenylamine under the action of a catalyst to obtain a first intermediate;

reacting the first intermediate alkyl with borate to obtain a second intermediate;

carrying out suzuki coupling reaction on the second intermediate and C6-C30 heterocyclic aryl containing halogen under the condition of an organic palladium catalyst to obtain a compound with a structure shown in a formula (II);

wherein Q is halogen.

The invention provides application of the red light metal complex in the technical scheme in an organic electroluminescent device.

The present invention provides an organic electroluminescent device comprising: the organic electroluminescent device comprises a cathode, an anode and at least one organic layer serving as a light-emitting layer, and is characterized in that the light-emitting layer contains at least one red light metal complex.

Compared with the prior art, the invention provides a red light metal complex shown as a formula (I): wherein m is 2, n is 1 or m is 3, n is 0; r₁Independently selected from C1-C10 alkyl, C1-C10 substituted alkyl and C6-C10 aryl; r₂Independently selected from C1-C10 alkyl, C6-C25 aryl and C6-C25 heterocyclic aryl; ar is C6-C30 heterocyclic aryl. The invention uses aromatic groupsThe fluorene is connected as a main group, and the triphenylamine is used as an end-capping group, so that the interaction force between dye molecules is reduced by the synergistic effect of the fluorene and the triphenylamine and the steric hindrance effect of the triphenylamine, the self-quenching phenomenon of triplet excitons in the solid film is reduced, and simultaneously, the HOMO energy level is effectively raised by the strong electron-donating effect of the triphenylamine, so that the band gap is reduced, and the spectrum is red-shifted. The red to deep red phosphorescent iridium complex prepared by the method has good solubility in common solvents, is beneficial to preparing solution processing type devices, and the prepared organic electroluminescent device has high luminous efficiency and power efficiency.

Drawings

FIG. 1 is a graph of the absorption and PL spectra of complexes prepared in examples 4 and 5 of the present invention;

FIG. 2 shows the performance of a device prepared in example 6 of the present invention;

FIG. 3 is an external quantum efficiency-doping concentration efficiency curve of devices prepared in example 6 of the present invention and comparative example 1;

FIG. 4 shows the performance of the device prepared in example 7 of the present invention.

Detailed Description

The invention provides a red light metal complex shown as a formula (I):

wherein m is 2, n is 1 or m is 3, n is 0;

that is, the red-light metal complex represented by formula (I) may specifically be of the following structure:

R₁independently selected from C1-C10 alkyl, C1-C10 substituted alkyl and C6-C10 aryl;

preferably, said R is₁Independently selected from C1-C10 alkyl, C1-C10 substituted alkyl, C6-C10 aryl and substituted C6-C10 aryl; more preferably, it is a mixture of more preferably,the R is₁Independently selected from C1-C5 alkyl, C1-C5 substituted alkyl, C6-C10 aryl and substituted C6-C10 aryl; the substituent of the substituted alkyl is halogen; the substituent of the substituted aryl is halogen.

Wherein, the specific alkyl of C1-C5 comprises methyl, ethyl, propyl, butyl and pentyl; the above-mentioned substituents which may be linear or branched; most preferably, said R₁Independently selected from methyl, trifluoromethyl, tert-butyl or phenyl. The aryl group in the invention includes but is not limited to one or more of benzene, biphenyl, naphthalene, anthracene, phenanthrene, pyrene and perylene.

In the present invention, R₂Independently selected from C1-C10 alkyl, C6-C25 aryl and C6-C25 heterocyclic aryl; preferably, said R is₂Independently selected from substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C25 aryl, substituted or unsubstituted C6-C25 heterocyclic aryl; more preferably, R is₂Independently selected from C1-C5 alkyl, C6-C22 substituted or unsubstituted aryl, C6-C22 substituted or unsubstituted heterocyclic aryl; most preferably, said R₂Independently selected from C1-C5 alkyl, C6-C20 substituted or unsubstituted aryl, C6-C20 substituted or unsubstituted heterocyclic aryl; the heteroatom of the heterocyclic aryl group is O, S or N; the substituent of the substituted aryl is preferably one or more of halogen, cyano, alkyl, alkoxy, ester group, amino, borate group, acyl, amido, aryloxy or heterocyclic group; the substituent of the substituted heterocyclic aryl is preferably one or more of halogen, cyano, alkyl, alkoxy, ester group, amino, borate group, acyl, amido, aryloxy or heterocyclic group.

Specifically, the aryl group of the invention includes but is not limited to one or more of benzene, biphenyl, naphthalene, anthracene, phenanthrene, pyrene, perylene; the heterocyclic aryl provided by the invention comprises but is not limited to one or more of pyrrole, pyridine, furan, thiophene and carbazole.

In the invention, Ar is C6-C30 heterocyclic aryl.

More preferably, Ar is a structure represented by the formula (a-1) to the formula (a-8):

in the present invention, the alkyl group is preferably a straight-chain alkyl group, a branched-chain alkyl group, a cyclic alkyl group, a straight-chain alkyl group substituted with at least 1 substituent, a branched-chain alkyl group substituted with at least 1 substituent, or a cyclic alkyl group substituted with at least 1 substituent; the substituent is independently selected from one or more of halogen and cyano, and the number of the substituent on the alkyl is preferably 1-5, more preferably 1, 2, 3 or 4.

The alkoxy group is preferably an unsubstituted alkoxy group or an alkoxy group substituted with at least 1 substituent; the substituent is independently selected from one or more of halogen and cyano, and the number of the substituent on the alkoxy is preferably 1-5, more preferably 1, 2, 3 or 4.

The aryl group is preferably an unsubstituted aryl group or an aryl group substituted with at least 1 substituent; the number of the substituents on the aryl group is preferably 1 to 5, and more preferably 1, 2, 3 or 4.

The heterocyclic group is preferably an unsubstituted heterocyclic group or a heterocyclic group substituted with at least 1 substituent; wherein the heteroatom in the heterocyclic group is nitrogen, sulfur or oxygen; the number of substituents on the heterocyclic group is preferably 1 to 5, more preferably 1, 2, 3 or 4.

In the present invention, the compound represented by the formula (I) has the following structure:

or

The source of iridium chloride trihydrate is not limited in the present invention, and may be commercially available.

The compound of formula (II) is not limited in its origin, and may be commercially available or prepared by the following method:

q is halogen, preferably fluorine, chlorine, bromine, iodine; more preferably bromine.

The source of formula (III) in the present invention is not limited, and may be commercially available or prepared according to a conventional method known to those skilled in the art. The following examples are given for 4-iodotriphenylamine and bromine-substituted fluorene:

in the invention, firstly, a compound with a structure shown in a formula (III) and 4-iodotriphenylamine react under the action of a catalyst to obtain a first intermediate; preferably, in the presence of a protective gas, the compound with the structure of the formula (III) and 4-iodotriphenylamine are dissolved in a solvent, mixed with potassium hydroxide in the presence of a catalyst, reacted, separated and purified to obtain a first intermediate.

The protective gas is not limited in the present invention, and may be nitrogen, helium, neon, or argon.

Wherein, the catalyst is preferably a mixture of cuprous chloride and phenanthroline; the mass ratio of the cuprous chloride to the phenanthroline is (0.1-0.3) to (0.2-0.6);

the mol ratio of the compound with the structure of the formula (III) to 4-iodotriphenylamine is preferably 1: (2.1-3.0); the mol ratio of the compound with the structure of the formula (III), 4-iodotriphenylamine, the catalyst, potassium hydroxide and the solvent is preferably 1: (2.1-3.0): (0.1-0.6): (7-10): (2-50).

The reaction temperature is 130-150 ℃; more preferably 140-145 ℃; the reaction time is preferably 36-48 h. The reaction is preferably carried out under stirring, and the stirring is not limited in the present invention and may be well known to those skilled in the art.

The solvent is preferably p-xylene.

After the reaction is finished, separation and purification are preferred, and the specific mode of the separation and purification is not limited in the present invention, and those skilled in the art are familiar with the following methods: and cooling to room temperature after reaction, extracting with ethyl acetate, separating liquid, washing an organic phase with water, drying, filtering, drying in a rotary manner, and separating by silica gel column chromatography by using dichloromethane/petroleum ether as an eluent to obtain a first intermediate.

Wherein the first intermediate structure is represented by formula (IV);

wherein R is₂As mentioned above, no further description is provided herein.

After the first intermediate is obtained, the first intermediate is reacted with an alkyl borate to obtain a second intermediate.

The first intermediate, solvent, n-butyl lithium and alkyl borate are reacted, preferably in the presence of a protective gas, to give a second intermediate. Specifically, in the presence of protective gas, a first intermediate, a solvent and n-butyllithium react at-78 ℃, and then react with alkyl borate at room temperature to obtain a second intermediate. And separating after the reaction to obtain a second intermediate.

Wherein the mass ratio of the first intermediate, the solvent, the n-butyl lithium and the alkyl borate is preferably 1: (2-50): (1.1-1.2): (3-5). The alkyl borate is preferably trimethyl borate.

The separation is specifically as follows: and adding acid after reaction to make the solution acidic, then extracting with diethyl ether, separating liquid, washing the organic phase with water, drying, filtering, spin-drying, and washing with petroleum ether.

The solvent is preferably tetrahydrofuran; the reaction time at-78 ℃ is 40-60 min; and reacting at room temperature for 4-12 h. The protective gas is not limited in the present invention, and may be nitrogen, helium, neon, or argon.

Wherein the structure of the second intermediate is shown as a formula (V);

wherein R is₂As mentioned above, no further description is provided herein.

After a second intermediate is obtained, carrying out suzuki coupling reaction on the second intermediate and C6-C30 heterocyclic aryl containing halogen under the condition of an organic palladium catalyst to obtain a compound with a structure shown in a formula (II);

the preferable concrete is as follows: in the presence of protective gas, dissolving the second intermediate and C6-C30 heterocyclic aryl containing halogen in a solvent, and carrying out suzuki coupling reaction under the conditions of an organic palladium catalyst, 2-dicyclohexylphosphine-2 ',6' -dimethoxybiphenyl (s-phos) and an aqueous solution of carbonate to obtain a compound with a structure shown in a formula (II);

wherein the organic palladium catalyst is preferably tris (dibenzylideneacetone) dipalladium or palladium acetate; the mol ratio of the organic palladium catalyst to the C6-C30 heterocyclic aryl is preferably 3:100-5: 100; the molar ratio of the palladium catalyst to s-phos is preferably 1: 2-6, and the carbonate is preferably at least one of potassium carbonate and sodium carbonate.

The solvent is toluene or tetrahydrofuran; the molar ratio of the second intermediate to the halogen-containing C6-C30 heterocyclic aryl is 1: (1.1-1.5); the reaction temperature is 80-115 ℃; the reaction time is 8-24 h;

after the reaction, separating and purifying to obtain a compound with a structure of a formula (II); the separation and purification is preferably carried out by extracting with ethyl acetate, separating, washing with water, drying, filtering, spin-drying, and separating with silica gel column chromatography as eluent selected from petroleum ether/ethyl acetate.

After preparing the compound with the structure of the formula (II), reacting the compound with the structure of the formula (II) with iridium chloride trihydrate to obtain an intermediate;

and (3) reacting the intermediate with acetylacetone to obtain the red light metal complex shown in the formula (I).

In the invention, the compound with the structure of formula (II) is reacted with iridium chloride trihydrate to obtain an intermediate.

Preferably, the compound with the structure of the formula (II) reacts with iridium chloride trihydrate in a solvent in the presence of a protective gas to obtain an intermediate.

Wherein the molar ratio of the compound with the structure of the formula (II) to the iridium chloride trihydrate is preferably (2-3): 1; the solvent is preferably a mixture of 2-ethoxyethanol, dioxane and water, and the volume ratio of the 2-ethoxyethanol to the water is preferably 3:1: 1; the reaction temperature is preferably 70-130 ℃; more preferably 100-120 ℃; the reaction time is preferably 20-24 h.

Separating and purifying after reaction to obtain an intermediate; the intermediate is the structure shown in the formula (VI);

wherein the separation and purification is preferably carried out by cooling to room temperature, rotary steaming, washing with water and filtering to obtain a solid; washing the solid with distilled water and methanol in sequence, and drying.

The present invention is not limited to the above-mentioned specific procedures for separation and purification, and those skilled in the art will be familiar with them.

After obtaining the intermediate, reacting the intermediate with acetylacetone to obtain the red light metal complex shown in the formula (I).

Preferably, the intermediate and acetylacetone react in the presence of a solvent and sodium carbonate to obtain the red-light metal complex shown in the formula (I).

The molar ratio of the intermediate to the acetylacetone is preferably 1: (3-5); the solvent is preferably a mixed solvent of 2-ethoxyethanol and dioxane. The reaction temperature is preferably 70-130 ℃; more preferably 100-120 ℃; the reaction time is preferably 20-24 h.

Separating and purifying after the reaction to obtain the red light metal complex shown in the formula (I-a).

Wherein the separation and purification is preferably carried out by cooling to room temperature, removing the solvent, mixing with water, extracting with dichloromethane, separating, washing with water, drying, and removing the organic phase solvent to obtain a solid; separating the solid by silica gel column chromatography with mixed solvent of petroleum ether and ethyl acetate, and recrystallizing to obtain the red light metal complex.

Alternatively, the first and second electrodes may be,

reacting the intermediate with the structure shown in the formula (VI) with the compound with the structure shown in the formula (II) to obtain the red light metal complex shown in the formula (I-b);

preferably, the intermediate with the structure shown in the formula (VI) and the compound with the structure shown in the formula (II) react in the presence of a solvent, silver trifluoromethanesulfonate and potassium carbonate to obtain the red light metal complex shown in the formula (I-b).

Wherein the molar ratio of the intermediate with the structure shown in the formula (VI) to the compound with the structure shown in the formula (II) is preferably 1 (1.1-3); the reaction temperature is 160-180 ℃; the reaction time is 24-48 h.

The solvent is mesitylene; the separation and purification after the reaction are the same as those described above, and are not described herein.

The invention provides a red light metal complex shown as a formula (I): wherein m is 2, n is 1 or m is 3, n is 0; r₁Independently selected from C1-C10 alkyl, C1-C10 substituted alkyl and C6-C10 aryl; r₂Independently selected from C1-C10 alkyl, C6-C25 aryl and C6-C25 heterocyclic aryl; ar is C6-C30 heterocyclic aryl. According to the invention, the aromatic group is connected with fluorene as a main group, and triphenylamine is used as an end-capping group, so that the interaction force between dye molecules is reduced due to the synergistic effect of the aromatic group and the triphenylamine and the steric hindrance effect of the triphenylamine, the self-quenching phenomenon of triplet excitons in a solid film is reduced, and simultaneously, the strong electron-donating effect of the triphenylamine effectively raises the HOMO energy level, thereby reducing the band gap and realizing red shift of the spectrum. The red to deep red phosphorescent iridium complex prepared by the method has good solubility in common solvents, is beneficial to preparing solution processing type devices, and the prepared organic electroluminescent device has high luminous efficiency and power efficiency.

The organic light emitting device is just one well known to those skilled in the art, and the present invention preferably includes a cathode, an anode, and at least one organic layer as a light emitting layer; the organic layer contains the above-described red-light metal complex. The red-light metal complex may be in a single form, or may be mixed with other substances, and contained in the organic layer.

In the present invention, the anode material is preferably indium tin oxide. The cathode is preferably a metal, including but not limited to calcium, magnesium, barium, aluminum, and silver; preferably aluminum.

In the present invention, the organic layer refers to all layers between the cathode and the anode of the organic light emitting device. At least one of the organic layers is a light-emitting layer.

According to the present invention, the organic layer preferably includes one or more layers selected from a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport functions, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a layer having both electron transport and electron injection functions, and more preferably includes a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, which are provided in this order, or a layer having both hole injection and hole transport functions, an electron blocking layer, a light emitting layer, a hole blocking layer, and a layer having both electron transport and electron injection functions, which are provided in this order.

The thickness of the electron transmission layer is preferably 50-100 nm; the thickness of the substrate is preferably 0.5-0.7 mm.

When the organic layer of the present invention includes a hole injection layer, a hole transport layer, or a layer having both hole injection and hole transport properties, it is preferable that at least one of the hole injection layer, the hole transport layer, or the layer having both hole injection and hole transport properties includes a hole injection material, a hole transport material, or a material having both hole injection and hole transport properties.

When the organic layer is of a single-layer structure, the organic layer is a light-emitting layer, and when the organic layer is of a multilayer structure, the organic layer comprises a light-emitting layer; the light-emitting layer preferably comprises one or more of a phosphorescent host, a fluorescent host, a phosphorescent doped material and a fluorescent doped material; one or more of the phosphorescent host, the fluorescent host, the phosphorescent doped material and the fluorescent doped material is a red light metal complex shown in a formula (I).

The light-emitting layer is preferably red or deep red.

When the organic layer includes an electron transport layer, the electron transport layer may include a red-emitting metal complex and/or a metal compound represented by formula (I). The metal compound is not particularly limited as long as it is a substance for electron transport, which is well known to those skilled in the art.

When the organic layer comprises the light-emitting layer and the electron transport layer at the same time, the light-emitting layer and the electron transport layer can respectively comprise the red light metal complex shown in the formula (I) with the same or different structures.

The organic light-emitting device provided by the invention is prepared by using the red light metal complex shown in the formula (I) and conventional materials, the preparation method of the organic light-emitting device is not limited, the conventional method in the field can be used, and the invention preferably uses the methods of thin film evaporation, electron beam evaporation or physical vapor deposition and the like to evaporate metal, oxide with conductivity and alloy thereof on a substrate to form an anode, and then forms an organic layer and an evaporation cathode on the anode to obtain the organic light-emitting device.

The organic layer and the anode material are sequentially evaporated on the cathode material layer on the outer substrate to manufacture the organic light-emitting device.

The organic layer may include a multi-layer structure of the hole injection layer, the hole transport layer, the light emitting layer, the hole blocking layer and the electron transport layer, and the multi-layer structure may be formed by evaporation using the above-mentioned thin film evaporation, electron beam evaporation or physical vapor deposition, or various polymer solvent engineering techniques may be used instead of the evaporation method, such as spin-coating (spin-coating), tape-casting (tape-casting), doctor-blading (doctor-blading), Screen-Printing (Screen-Printing), inkjet Printing or Thermal-Imaging (Thermal-Imaging) to reduce the number of layers.

The organic light-emitting device provided by the invention can be divided into front light-emitting, back light-emitting or double-sided light-emitting according to the used materials; and the organic light emitting device may be applied to an Organic Light Emitting Device (OLED), an Organic Solar Cell (OSC), an electronic paper (e-paper), an Organic Photoreceptor (OPC), or an Organic Thin Film Transistor (OTFT) in the same principle.

In order to further illustrate the present invention, the following examples are given to describe the red-emitting metal complexes provided by the present invention in detail.

Example 1

Under argon protection, compound (1) (1.56g, 5mmol), 4-iodotriphenylamine (4.22g, 11.39mmol), cuprous chloride (0.20g, 2mmol), phenanthroline (0.79g, 4mmol), potassium hydroxide (2.24g, 40mmol) and p-xylene (50mL) were added to a round-bottom flask, stirred vigorously, and warmed to reflux for 36 hours. After the reaction, the reaction mixture was cooled to room temperature, extracted with ethyl acetate, separated, the organic phase was washed with water three times, dried over anhydrous sodium sulfate, filtered, and spin-dried, and then subjected to silica gel column chromatography using dichloromethane/petroleum ether as an eluent to obtain a pale yellow solid with a yield of 45%. The results of nuclear magnetic identification are as follows:¹HNMR(400MHz,DMSO)[ppm]:7.75(s,1H),7.73(s,1H),7.67(s,1H),7.65(s,1H),7.61(d,J＝1.7Hz,1H),7.48(dd,J＝8.1,1.9Hz,1H),7.32–7.25(m,8H),7.08–6.95(m,20H),1.97–1.86(m,4H),0.27(t,J＝7.3Hz,8H).¹³C NMR(101MHz,CDCl₃)[ppm]:152.32,151.14,148.14,147.92,143.16,143.12,140.50,135.22,130.27,129.35,126.13,125.52,124.99,124.07,123.15,122.64,120.84,120.56,120.41,118.52,56.24,32.35,8.45.MALDI-TOF：801.3

compound (2) (1.75g, 2mmol) was dissolved in 50mL of dry tetrahydrofuran under an argon atmosphere, 2.5M n-butyllithium (1mL) was added dropwise under an acetone bath (-78 ℃ C.) to react for 1 hour, after which the acetone bath was removed, triisopropyl borate (1.4mL) was added and the reaction was carried out at room temperature for 4 hours. After the reaction is finished, adding dilute hydrochloric acid to make the solution acidic, extracting with diethyl ether, separating liquid, washing an organic phase with water for three times, drying the organic phase with anhydrous sodium sulfate, filtering the organic phase, drying in a rotary manner, and washing with petroleum ether for three times to obtain a second intermediate, namely the compound 3.

EXAMPLE 2 ligand DTPAA-Flpy-CF₃Synthesis of (2)

Under the protection of argon, 2-chloro-5-trifluoromethylpyridine (0.44g, 2.44mmol), compound (3) (2.34g), Pd were added to a round-bottom flask₂(dba)₃(0.11g, 0.12mmol), s-phos (0.25g, 0.61mmol) and 2M potassium carbonate solution (10mL) were added to 80mL of toluene, and the mixture was heated to reflux and reacted for 24 hours. After the reaction is finished, extracting by ethyl acetate, separating liquid and washing by water untilNeutral, dried over anhydrous sodium sulfate. After filtration and spin-drying, silica gel column chromatography using petroleum ether/dichloromethane as eluent gave a yellow solid in 51% yield after drying. The results of nuclear magnetic identification are as follows:¹H NMR(400MHz,DMSO)[ppm]:9.04(s,1H),8.27(s,2H),8.21(s,1H),8.19–8.10(m,1H),7.86(d,J＝8.0Hz,1H),7.82(s,1H),7.36–7.23(m,8H),7.14–6.92(m,20H),6.52–6.47(m,1H),5.75(s,1H),0.86(s,4H),0.31(t,J＝7.1Hz,6H).¹³C NMR(101MHz,C₆D₆)[ppm]:160.87,152.47,150.91,148.40,148.28,146.53,146.49,143.82,143.39,143.27,136.21,135.60,133.43,133.39,129.49,126.80,125.64,125.29,124.24,123.16,122.80,121.94,121.41,119.48,119.29,118.60,56.38,32.73,8.75.MALDI-TOF：868.4。

EXAMPLE 3 Synthesis of ligand DTPAA-Fliq

Under the protection of argon, 1-chloroisoquinoline (0.39g, 2.38mmol), boric acid (2.38g), Pd (OAc)₂(0.016g, 0.072mmol), s-phos (0.06g, 0.143mmol) and 2M potassium carbonate solution (7mL) were added to 100mL toluene, followed by a drop of phase transfer catalyst, heating to reflux, and reaction for 24 h. After the reaction, the mixture was extracted with ethyl acetate, separated, washed with water to neutrality, and dried over anhydrous sodium sulfate. Filtration and spin-drying followed by silica gel column chromatography using petroleum ether/ethyl acetate as eluent gave an orange solid in 44% yield after drying. The results of nuclear magnetic identification are as follows: DTPA-Fliq:¹HNMR(400MHz,DMSO)[ppm]:8.58(d,J＝5.6Hz,1H),8.05(d,J＝8.5Hz,2H),7.82(ddd,J＝22.1,14.5,7.9Hz,4H),7.70–7.54(m,3H),7.28(t,J＝7.8Hz,8H),7.14–6.88(m,22H),1.95(d,J＝8.0Hz,4H),0.33(dd,J＝25.2,18.0Hz,6H).¹³C NMR(101MHz,C₆D₆)[ppm]:161.37,152.29,150.21,148.32,147.90,143.49,143.14,142.89,141.95,138.40,137.24,136.28,129.83,129.60,129.49,127.80,127.21,127.17,126.96,125.75,125.25,125.13,124.18,123.43,122.73,121.19,119.62,118.98,118.96,56.35,32.68,8.87.MALDI-TOF:850.3。

example 4 treatment with DTPAA-Flpy-CF₃Metal iridium complex (Ir (DTPAA-Flpy-CF) as ligand₃)₂acac) Synthesis

Under the protection of argon, iridium chloride trihydrate (0.1g, 0.40mmol), ligand DTPAA-Flpy-CF₃(0.8g, 0.92mmol) was dissolved in a mixture of ethylene glycol monoethyl ether (15mL), dioxane (5mL) and water (5mL), and the mixture was heated to reflux for 36 hours. Cooling to room temperature, rotary evaporating part of solvent, adding appropriate amount of distilled water, and filtering. The solid is washed by distilled water and methanol in sequence, and is dried to obtain red solid, and the dimer can be directly put into the next reaction without further purification.

Dimer (0.5g) and acetylacetone (0.5mL) were dissolved in ethylene glycol monoethyl ether (15mL) and dioxane (5mL) under argon, sodium carbonate (0.14g, 1.27mmol) was added, the mixture was heated to reflux, and the reaction was carried out for 36 hours and 24 hours. Cooling to room temperature, removing part of the solvent, adding appropriate amount of distilled water, extracting with dichloromethane, separating, washing with water to neutrality, drying with anhydrous sodium sulfate, removing the solvent from the organic phase to obtain red solid, separating and purifying with silica gel column chromatography using petroleum ether/dichloromethane (volume ratio of 1:1) as eluent, removing the solvent, drying, and recrystallizing with mixed solution of dichloromethane and methanol to obtain red solid with a yield of 40%. The results of nuclear magnetic identification are as follows:¹H NMR(400MHz,DMSO)[ppm]:8.67(s,2H),8.50(d,J＝9.0Hz,2H),8.36(d,J＝9.5Hz,2H),7.90(s,2H),7.31–7.24(m,16H),7.14(d,J＝8.1Hz,2H),7.03–6.87(m,44H),6.33(s,2H),5.39(s,1H),1.87(d,J＝32.0Hz,8H),1.77(s,6H),0.34(t,J＝7.2Hz,6H),0.05(t,J＝7.2Hz,6H).¹³C NMR(101MHz,C₆D6)[ppm]:184.29,171.75,151.52,148.71,147.03,146.54,144.10,144.05,143.32,142.24,142.13,141.70,140.02,134.63,132.25,128.17,124.42,123.66,122.87,122.82,122.63,122.02,121.88,121.68,121.38,121.05,120.36,118.68,117.35,116.68,99.55,54.06,31.73,31.42,28.81,27.01,7.67,7.49,0.00.Anal.Calcd.for C₁₂₃H₉₉F₆IrN₈O₂:C,64.17；H,4.84；N,3.79.Found:C,64.15；H.4.82；N,3.75.MALDI-TOF：2026.7。

example 5 Metal Iridium Complex (Ir (DTPAA-Fliq) with DTPAA-Fliq) as ligand₂acac) Synthesis

Under the protection of argon, iridium chloride trihydrate (0.28g, 0.48mmol), ligand DTPAA-Flpy-CF₃(0.87g, 1.02mmol) was dissolved in a mixture of ethylene glycol monoethyl ether (24mL), dioxane (8mL) and water (8mL), and the mixture was heated to reflux for 36 hours. Cooling to room temperature, rotary evaporating part of solvent, adding appropriate amount of distilled water, and filtering. The solid is washed by distilled water and methanol in sequence, and is dried to obtain red solid, and the dimer can be directly put into the next reaction without further purification.

Dimer (0.64g) and acetylacetone (0.5mL) were dissolved in ethylene glycol monoethyl ether (24mL) and dioxane (8mL) under argon, sodium carbonate (0.174g, 1.64mmol) was added, the mixture was heated to reflux, and the reaction was carried out for 36 hours for 24 hours. Cooling to room temperature, removing part of the solvent, adding appropriate amount of distilled water, extracting with dichloromethane, separating, washing with water to neutral, drying with anhydrous sodium sulfate, removing the solvent in the organic phase to obtain red solid, separating and purifying with silica gel column chromatography with petroleum ether/ethyl acetate (volume ratio of 1:1) as eluent, removing the solvent, and drying to obtain red solid with yield of 20%. The results of nuclear magnetic identification are as follows:¹H NMR(400MHz,DMSO)[ppm]:8.91(s,2H),8.41(d,J＝6.3Hz,2H),8.16(s,2H),8.07(s,2H),7.88(s,4H),7.76(d,J＝6.2Hz,2H),7.24(t,J＝7.8Hz,16H),7.13–6.56(m,44H),6.46(s,2H),5.28(s,1H),1.85(d,J＝43.2Hz,8H),1.71(s,6H),0.34(t,J＝7.0Hz,6H),0.06(t,J＝7.2Hz,6H).¹³C NMR(101MHz,C₆D₆))[ppm]:184.82,170.45,153.11,152.52,148.36,147.23,145.01,143.65,142.75,142.69,142.59,141.36,137.57,136.52,130.31,129.42,127.32,127.17,126.60,125.81,124.78,124.41,124.01,123.24,122.56,121.63,118.92,100.72,55.41,32.90,32.68,28.58,9.06,8.78.MALDI-TOF-MS:1990.8.Anal.Calcd.for C₁₂₉H₁₀₅IrN₈O₂:C,77.80；H,5.31；N,5.63；Found:C,77.89；H,5.33；N,5.60。

the absorption and photoluminescence spectra of the complexes prepared in examples 4 and 5 of the present invention were measured, and the results are shown in fig. 1, and fig. 1 is a graph showing the absorption and PL spectra of the complexes prepared in examples 4 and 5 of the present invention.

Example 6

Cleaning Indium Tin Oxide (ITO) conductive glass (ITO glass) by using an ITO cleaning agent, cleaning by using distilled water, and finally treating by using ultraviolet ozone (UVO) for 25 min; spin-coating polyethylenedioxythiophene-poly (styrene sulfonate) (PEDOT) on indium tin oxide conductive glass at 3000 r/min for one minute, and baking at 120 ℃ for 1 hour to obtain the anode of the organic electroluminescent device. The anode is disposed on the substrate.

Mixing 10mg of 4,4' -tris (N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) with the iridium complex prepared in example 4 and 1mL of chlorobenzene to prepare a 10mg/mL chlorobenzene solution, spin-coating the solution on the anode at a speed of 1500 rpm for one minute, and performing heat treatment at 100 ℃ for 30 minutes in an inert atmosphere to obtain an organic electroluminescent layer;

evaporating a 50 nm-thick electron injection/transmission layer 1,3, 5-tri [ (3-pyridyl) -3-phenyl ] benzene (TmPyPB) on the organic electroluminescent layer under the vacuum degree of 4 x 10 < -4 > Pa, then evaporating 1 nm-thick LiF and 100 nm-thick Al, wherein the LiF and the Al are composite cathode electrodes, and finally obtaining the organic electroluminescent layer with the structure of ITO/PEDOT: PSS (40 nm)/m-MTDATA: x wt.% iridium complex/TmPyPB (60nm)/LiF (1nm)/Al (100nm) organic electroluminescent device.

As shown in fig. 2, in which fig. 2 is a graph showing the performance of the device prepared in example 6 of the present invention, the current-voltage-luminance characteristics and the lumen efficiency-luminance-power efficiency curves of the organic electroluminescent device were measured by a Keithley source measuring system (Keithley2400 Sourcemeter). All measurements were performed at room temperature in the atmosphere. The measured starting voltage of the organic electroluminescent device is 2.2V, the maximum lumen efficiency is 40.1cd/A, the maximum power efficiency is 52.2lm/W, the maximum external quantum efficiency is 23.0%, the color coordinate is (0.63,0.37), the performance of the device is not changed greatly from 5 wt% to 20 wt% along with the increase of the doping concentration, which indicates that the intermolecular interaction is inhibited to a certain extent and the concentration quenching of excitons is inhibited.

Example 7

Mixing 10mg of 4,4' -tris (N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) with the iridium complex prepared in example 5 and 1mL of chlorobenzene to prepare a 10mg/mL chlorobenzene solution, spin-coating the solution on the anode at a speed of 1500 rpm for one minute, and performing heat treatment at 100 ℃ for 30 minutes in an inert atmosphere to obtain an organic electroluminescent layer;

Fig. 4 is a performance curve of the device prepared in example 7 of the present invention, and the current-voltage-luminance characteristics and the lumen efficiency-luminance-power efficiency curve of the organic electroluminescent device were measured by a Keithley source measuring system (Keithley2400 Sourcemeter). All measurements were performed at room temperature in the atmosphere. The measured starting voltage of the organic electroluminescent device is 2,4V, the maximum current efficiency is 1.5cd/A, the maximum power efficiency is 1.9lm/W, the maximum external quantum efficiency is 7.6%, the color coordinate is (0.69,0.28), the performance of the device is not changed greatly from 5 wt% to 20 wt% along with the increase of the doping concentration, and the method indicates that the intermolecular interaction is inhibited to a certain extent and the concentration quenching of excitons is inhibited.

Comparative example 1

10mg of 4,4' -tris (N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) was reacted with a literature-reported iridium complex

Mixing with 1mL of chlorobenzene to prepare a 10mg/mL chlorobenzene solution, spinning and coating the solution on the anode for one minute at the speed of 1500 rpm, and carrying out heat treatment at 100 ℃ for 30min in an inert atmosphere to obtain an organic electroluminescent layer;

evaporating a 50 nm-thick electron injection/transmission layer 1,3, 5-tri [ (3-pyridyl) -3-phenyl ] benzene (TmPyPB) on the organic electroluminescent layer under the vacuum degree of 4 x 10 < -4 > Pa, then evaporating 1 nm-thick LiF and 100 nm-thick Al, wherein the LiF and the Al are composite cathode electrodes, and finally obtaining the organic electroluminescent layer with the structure of ITO/PEDOT: PSS (40 nm)/m-MTDATA: x wt.% iridium complex/TmPyPB (60nm)/LiF (1nm)/Al (100nm) organic electroluminescent device. The above organic electroluminescent device current-voltage-luminance characteristics and lumen efficiency-luminance-power efficiency curves were tested by a Keithley source measuring system (Keithley2400 Sourcemeter). All measurements were performed at room temperature in the atmosphere. The measured starting voltage of the organic electroluminescent device is 2.3V, the performance is optimal when the organic electroluminescent device is doped with 3 wt%, the maximum power efficiency is 44.5lm/W, the maximum external quantum efficiency is 19.3%, and the color coordinate is (0.64, 0.36).

As shown in fig. 3, fig. 3 is an external quantum efficiency-luminance curve of the devices prepared in example 6 of the present invention and comparative example. As can be seen from fig. 3, as the doping concentration increases, the maximum external quantum efficiency of the device prepared in comparative example 1 decreases from 17.6% to 9.6% from 5 wt% to 20 wt%, and the maximum external quantum efficiency of the device prepared in inventive example 6 decreases from 23.0% to 20.1%, which is smaller than that of comparative example 1, indicating that concentration quenching is suppressed to some extent by using triphenylamine as the end capping group in the present invention.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A red-light metal complex represented by the formulae (I-1) to (I-15):

2. a method for preparing a red-emitting metal complex according to claim 1, comprising:

reacting the intermediate with acetylacetone to obtain red light metal complexes shown in formulas (I-1) to (I-15);

or

reacting the intermediate with a compound with a structure of a formula (II) to obtain red light metal complexes shown in formulas (I-1) to (I-15);

wherein R is₂An ethyl group; ar is formula (a-1) to formula (b)a-8) is shown as follows:

3. the method according to claim 2, wherein the compound having the structure of formula (II) is prepared by:

reacting the first intermediate with alkyl borate to obtain a second intermediate;

carrying out suzuki coupling reaction on the second intermediate and Ar group containing halogen under the condition of an organic palladium catalyst to obtain a compound with a structure shown in a formula (II);

wherein Q is halogen.

4. Use of the red-emitting metal complex of claim 1 in an organic electroluminescent device.

5. An organic electroluminescent device comprising: a cathode, an anode and at least one organic layer as a light-emitting layer, wherein the light-emitting layer contains at least one red-emitting metal complex according to claim 1.