阅读说明：本技术 空穴传输材料及其制备方法、电致发光器件 (Hole transport material, preparation method thereof and electroluminescent device ) 是由 王彦杰 罗佳佳 白科研 于 2020-12-08 设计创作，主要内容包括：本发明提供了一种空穴传输材料及其制备方法、电致发光器件。所述空穴传输材料的分子结构的主链中具有螺蒽芴结构,其分子结构的支链结构中具有芳基或杂芳基结构。本发明中所提供的空穴传输材料能够有效提高有机材料的空穴注入和传输性能,从而改善电致发光器件的电子和空穴平衡,达到较低的电压和较高的效率。(The invention provides a hole transport material, a preparation method thereof and an electroluminescent device. The main chain of the molecular structure of the hole transport material has a spiroanthracene fluorene structure, and the branched chain structure of the molecular structure of the hole transport material has an aryl or heteroaryl structure. The hole transport material provided by the invention can effectively improve the hole injection and transport performance of the organic material, thereby improving the electron and hole balance of the electroluminescent device and achieving lower voltage and higher efficiency.)

1. A hole transport material is characterized in that a main chain of a molecular structure of the hole transport material has a spiroanthracene fluorene structure, and the molecular structural formula of the hole transport material is as follows:

wherein Ar is₁、Ar₂、Ar₃And Ar₄Comprising at least one aryl or heteroaryl group;

r is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a);

R₁-R₆are respectively hydrogen, deuterium and C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀At least one of heteroaryl;

a. b, c and d are integers less than 5.

2. The hole transport material of claim 1, wherein Ar is₁、Ar₂、Ar₃And Ar₄The molecular structure of (a) is one of the following structures:

wherein, R is₇-R₁₀And said L is C₁-C₆₀Aryl or C of₁-C₆₀A heteroaryl group.

3. The hole transport material of claim 2, wherein L is one of the following group structures:

4. the hole transport material of claim 1, wherein the hole transport material is a polymer of the group consisting of poly (vinyl chloride), poly (In that, when a, b, c and d are 0, the R₃-R₆Respectively is one of hydrogen or deuterium; when a, b, c and d are 1-4, the R₃-R₆Are respectively C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀A heteroaryl group.

5. The hole transport material according to claim 4, wherein when a, b, c and d are 0, the molecular structural formula of the hole transport material is:

6. the hole transport material of claim 1, wherein R is one of the following group structures:

7. a method for preparing a hole transport material, comprising the steps of:

preparing a first compound: the molecular structure of the first compound comprises the following structure:

wherein R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a); x is one of halogen elements;

synthesizing a first target: placing the first compound and the second compound in a reaction container for deoxidation treatment; adding a catalyst into the reaction vessel, and fully reacting at the temperature of 50-150 ℃ to obtain a first solution; the second compound comprises at least one aryl or heteroaryl group in its molecular structure;

purifying the first target: purifying the first solution by a silica gel column chromatography method using an eluent to obtain the hole transport material.

8. The method for producing a hole transport material according to claim 7, wherein the step of producing the first compound further comprises the steps of:

preparation of a third compound: the molecular structure of the third compound comprises the following structure:

synthesizing a second target: placing the third compound, concentrated hydrochloric acid and glacial acetic acid in a reaction container, fully reacting at the temperature of 50-100 ℃, and adding sodium bicarbonate to obtain a second solution, wherein the second solution contains the second target substance;

and (3) extracting a second target: adding dichloromethane into the second solution for extraction to obtain a second target object;

and (3) purifying and treating a second target: purifying the second target by silica gel column chromatography using an eluent to obtain the first compound.

9. The method for producing a hole transport material according to claim 8, wherein the step of producing the third compound comprises the steps of:

dissolving a fourth compound in tetrahydrofuran, adding butyl lithium, and reacting to obtain a reaction solution; dissolving a fifth compound in tetrahydrofuran, dropwise adding the fifth compound into the reaction solution, and fully reacting to obtain a third solution; removing liquid in the third solution to obtain a third compound;

wherein the molecular structure of the fourth compound comprises the following structure:

y is a halogen element;

the molecular structural formula of the fifth compound has an anthracene structure.

10. An electroluminescent device, comprising:

a substrate layer;

the first electrode is arranged on the substrate layer;

a hole injection layer disposed on the first electrode;

a hole transport layer disposed on the hole injection layer;

a light emitting layer disposed on the hole transport layer;

an electron transport layer disposed on the light emitting layer;

the electron injection layer is arranged on the electron transport layer;

the second electrode is arranged on the electron injection layer;

wherein the hole injection layer and/or the hole transport layer has therein the hole transport material according to any one of claims 1 to 6.

Technical Field

The invention relates to the technical field of display, in particular to a hole transport material, a preparation method thereof and an electroluminescent device.

Background

The organic electronic device refers to a device composed of an anode, a cathode, and an organic layer sandwiched between the anode and the cathode, and includes an organic light emitting diode, an organic solar cell, an organic semiconductor, an organic crystal, and the like. The working principle is that an external voltage is applied to the electrode, and holes and electrons are injected into the organic layer to form excitons, so as to radiate light (organic light emitting diode); or the external light source is absorbed by the organic material to form excitons, and the excitons are separated into holes and electrons are transferred to the electrode to be stored (organic solar cell).

The organic layer of the organic electronic device is one or more layers of organic materials, such as hole injection or transport materials, electron injection or transport materials, or light emitting materials. Wherein these different organic materials operate on similar principles in different organic electronic devices:

an organic light emitting diode is a phenomenon of converting electric energy into light energy, and has a structure generally including an anode, a cathode, and a plurality of organic material layers interposed therebetween. The organic material layer is classified into a hole injection material, a hole transport material, an electron injection material, an electron transport material, and a light emitting material according to functions. Further, the light emitting materials are further classified into blue, sky blue, green, yellow, red, deep red, and the like light emitting materials according to emission colors.

The evaluation indexes of organic light emitting diodes are mainly voltage, efficiency and lifetime, and how to develop low-voltage, high-efficiency and long-lifetime electroluminescent devices is always the goal pursued by the research and development circles and the business circles, which requires high-mobility electron/hole injection and transport materials, high-efficiency light emitting materials and an effective balance of electrons and holes in the devices. In addition, the vapor deposition type (sublimation type or melting type), the decomposition temperature, the glass transition temperature, the outgassing phenomenon, and the like of the material must be considered also for mass productivity of the organic material. In particular, since a thick hole transport material needs to be deposited in mass production, and the sublimation type material among such materials seriously affects the uniformity of mass production film thickness, the development of a melt type hole transport material is also an important direction.

Disclosure of Invention

The invention aims to provide a hole transport material, a preparation method thereof and a display device, and aims to solve the problems that in the prior art, when the display device is prepared, the evaporated hole transport material is unstable and is not beneficial to mass production and the like.

In order to achieve the above object, the present invention provides a hole transport material, wherein a main chain of a molecular structure of the hole transport material has a spiroanthracene fluorene structure, and a molecular structural formula of the hole transport material is as follows:

wherein Ar is₁、Ar₂、Ar₃And Ar₄Comprising at least one aryl or heteroaryl group; r is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a); r₁-R₆Are respectively hydrogen, deuterium and C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀At least one of heteroaryl; a. b, c and d are integers less than 5.

Further, said Ar₁、Ar₂、Ar₃And Ar₄The molecular structure of (a) is one of the following structures:

wherein, R is₇-R₁₀And said L is C₁-C₆₀Aryl or C of₁-C₆₀A heteroaryl group.

Further, the L is one of the following group structures:

further, when a,b. When c and d are 0, the R₃-R₆Respectively is one of hydrogen or deuterium; when a, b, c and d are 1-4, the R₃-R₆Are respectively C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀A heteroaryl group.

Further, when a, b, c and d are 0, the molecular structural formula of the hole transport material is:

further, the R is one of the following group structures:

the invention also provides a preparation method of the hole transport material, which comprises the following steps:

preparing a first compound: the molecular structure of the first compound comprises the following structure:

wherein R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a); x is one of halogen elements.

Synthesizing a first target: and placing the first compound and the second compound in a reaction container for deoxidation treatment. Adding a catalyst into the reaction vessel, and fully reacting at the temperature of 50-150 ℃ to obtain a first solution. The second compound comprises at least one aryl or heteroaryl group in its molecular structure.

Purifying the first target: purifying the first solution by a silica gel column chromatography method using an eluent to obtain the hole transport material.

Further, the step of preparing the first compound further comprises the following steps:

preparation of a third compound: the molecular structure of the third compound comprises the following structure:

synthesizing a second target: and (3) putting the third compound, concentrated hydrochloric acid and glacial acetic acid into a reaction container, fully reacting at the temperature of 50-100 ℃, and adding sodium bicarbonate to obtain a second solution, wherein the second solution contains the second target substance.

And (3) extracting a second target: and adding dichloromethane into the second solution for extraction to obtain the second target substance.

And (3) purifying and treating a second target: purifying the second target by silica gel column chromatography using an eluent to obtain the first compound.

Further, the step of preparing the third compound comprises the following steps:

and dissolving the fourth compound in tetrahydrofuran, adding butyl lithium, and reacting to obtain a reaction solution. And dissolving the fifth compound in tetrahydrofuran, dropwise adding the solution into the reaction solution, and fully reacting to obtain a third solution. Removing the liquid in the third solution to obtain the third compound.

Wherein the molecular structure of the fourth compound comprises the following structure:

and Y in the molecular structure of the fourth compound is a halogen element. The molecular structural formula of the fifth compound has an anthracene structure.

The invention also provides an electroluminescent device which comprises a substrate layer, a first electrode, a hole injection layer, a hole transport layer, a luminescent layer, an electron transport layer, an electron injection layer and a second electrode. The first electrode is arranged on the substrate layer. The hole injection layer is arranged on the first electrode. The hole transport layer is disposed on the hole injection layer. The light-emitting layer is arranged on the hole transport layer. The electron transport layer is arranged on the luminous layer. The electron injection layer is arranged on the electron transmission layer. The second electrode is arranged on the electron injection layer.

Wherein the hole injection layer and/or the hole transport layer have therein the hole transport material as described above.

The invention has the advantages that: according to the hole transport material, the arylamine in the molecular structure can effectively improve the hole injection and transport performances of the organic material, so that the electron and hole balance of an electroluminescent device is improved, and lower voltage and higher efficiency are achieved. And the introduction of an alkyl, aryl or heteroaryl structure at the 4-position of fluorene can adjust the evaporation temperature, melting or sublimation characteristics, mobility and the like of the material, thereby being beneficial to the stability of mass production evaporation and improving the performance of devices.

Drawings

Fig. 1 is a schematic view of the layered structure of an electroluminescent device in an embodiment of the application of the present invention.

The components in the figures are represented as follows:

a substrate layer 1; a first electrode 2;

a hole injection layer 3; a hole transport layer 4;

an electron blocking layer 5; a light-emitting layer 6;

an electron transport layer 7; an electron injection layer 8;

a second electrode 9.

Detailed Description

The following are specific embodiments of the present invention to demonstrate that the present invention can be practiced, and the embodiments of the present invention will fully describe the present invention to those skilled in the art to make the technical content thereof more clear and easy to understand. The present invention may be embodied in many different forms of embodiments and should not be construed as limited to the embodiments set forth herein.

Example 1

The embodiment of the invention provides a hole transport material, wherein a main chain in a molecular structural formula of the hole transport material is a spiroanthracene fluorene structure, and the molecular structural formula is as follows:

wherein Ar is₁、Ar₂、Ar₃And Ar₄Comprising at least one aryl or heteroaryl group; r is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a); r₁-R₆Are respectively hydrogen, deuterium and C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀At least one of heteroaryl; a. b, c and d are integers less than 5.

Specifically, in the embodiment of the present invention, the molecular structure of Ar1 is:

and R is₇And R₈Is an aryl structure or a heteroaryl structure.

The structural formula of R is as follows:

a to d are all 0, and R₁-R₆Are all hydrogen bonds.

Specifically, the molecular structural formula of the hole transport material is as follows:

the embodiment of the invention also provides a preparation method of the hole transport material, which comprises the following preparation steps:

step S10) preparing a third compound: the molecular structural formula of the third compound comprises the following structure:

wherein X in the molecular structural formula is a halogen element, R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

Specifically, the step of preparing the third compound comprises the following steps:

the fourth compound (11mmol,3.43g) and tetrahydrofuran (20mL) were added to a reaction vessel, and the reaction vessel was placed under an argon atmosphere and dissolved with stirring. The reaction vessel was placed in an environment at a temperature of-60 ℃ to-90 ℃, preferably-78 ℃, butyllithium (7.5mL, 1.6M) was slowly dropped and the reaction was maintained for 1 hour to obtain a reaction solution. Wherein the molecular structure of the fourth compound comprises the following structure:

in the molecular structural formula, X and Y are halogen elements, and R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

The fifth compound (10mmol, 2.22g) was dissolved in tetrahydrofuran (20mL) and slowly dropped into the reaction solution also in an environment at a temperature of-60 ℃ to-90 ℃, preferably-78 ℃. After the completion of the dropwise addition, the reaction solution was warmed to room temperature and reacted for 12 hours. And after the reaction is finished, adding a proper amount of ammonium chloride to quench the reaction to obtain a third solution. Removing the liquid in the third solution by rotation to obtain the third compound. Wherein the molecular structural formula of the fifth compound has an anthracene structure.

Specifically, the fourth compound is 1-bromo-3' -chloro-4-phenyl biphenyl, and the fifth compound is 9, 9-dimethyl anthrone. The preparation flow of the third compound is shown as formula 1:

step S20) preparing a first compound: the molecular structural formula of the first compound comprises the following structures:

wherein X in the molecular structural formula is a halogen element, R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

Specifically, the step of preparing the first compound comprises the following steps:

step S21) synthesizing a second target: the third compound obtained in step S10 is placed in a reaction vessel, and concentrated hydrochloric acid (5mL) and glacial acetic acid (15mL) are added and reacted at a temperature of 50 to 100 ℃, preferably 80 ℃, for 24 hours to obtain a second solution. The second solution has a second target substance produced by the reaction.

Step S22) extracting a second target: after the second solution was cooled to room temperature, it was poured into ice water, and an aqueous sodium bicarbonate solution (1M) was added to neutralize the acidic solution in the second solution by sodium bicarbonate. Then, extraction was repeated three times using methylene chloride, and the extract obtained by the three-time extraction was washed three times with water, followed by drying using anhydrous sodium sulfate. And filtering and concentrating the dried extract to obtain the second target substance.

Step S23) purifying the second target: the organic material was separated and purified by 200-300 mesh silica gel column chromatography using petroleum ether and dichloromethane (volume ratio 4:1) as eluent to give about 4.31g of the first compound in 92% yield.

Specifically, the preparation flow of the first compound is shown as formula 2:

step S30) synthesizing a first target: the first compound (2.35g, 5mmol), the second compound (1.61g, 5mmol), t-BuONa (8mmol, 0.76g) and toluene (30mL) were placed in a reaction vessel and deoxygenated by passing nitrogen through the vessel. Then tris (dibenzylideneacetone) dipalladium (0.09mmol,81mg) and tri-tert-butylphosphine tetrafluoroborate (0.92mmol,0.24g) were added and reacted sufficiently at a temperature of 100 ℃ to 150 ℃, preferably at 110 ℃ to obtain a first solution. The first solution has a first target of the reaction synthesis therein. Wherein the second compound comprises at least one aryl or heteroaryl group in its molecular structure.

Step S40) purifying the first target: and cooling the first solution to room temperature, and concentrating the first solution to obtain the first target. Then, the organic material in the first target was separated and purified by 200-300 mesh silica gel column chromatography to obtain about 3.21g of the hole transport material with a yield of 85%.

Specifically, the second compound is di-4-phenyl-aniline. The preparation flow of the hole transport material is shown as formula 3

The arylamine introduced into the hole transport material provided by the embodiment of the invention can effectively improve the hole injection and transport performances of the organic material, thereby improving the electron and hole balance of an electroluminescent device and achieving lower voltage and higher efficiency. And the introduction of an alkyl, aryl or heteroaryl structure at the 4-position of fluorene can adjust the evaporation temperature, melting or sublimation characteristics, mobility and the like of the material, thereby being beneficial to the stability of mass production evaporation and improving the performance of devices.

Example 2

The embodiment of the invention provides a hole transport material, wherein a main chain in a molecular structural formula of the hole transport material is a spiroanthracene fluorene structure, and the molecular structural formula is as follows:

wherein Ar is₁、Ar₂、Ar₃And Ar₄Comprising at least one aryl or heteroaryl group; r is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a); r₁-R₆Are respectively hydrogen, deuterium and C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀At least one of heteroaryl; a. b, c and d are integers less than 5.

Specifically, in the embodiment of the present invention, the molecular structure of Ar1 is:

and R is₇And R₈Is an aryl structure or a heteroaryl structure.

The structural formula of R is as follows:

a to d are all 0, and R₁-R₆Are all hydrogen bonds.

Specifically, the molecular structural formula of the hole transport material is as follows:

the embodiment of the invention also provides a preparation method of the hole transport material, which comprises the following preparation steps:

step S10) preparing a third compound: the molecular structural formula of the third compound comprises the following structure:

wherein X in the molecular structural formula is a halogen element, R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

Specifically, the step of preparing the third compound comprises the following steps:

the fourth compound (11mmol,3.55g) and tetrahydrofuran (20mL) were added to a reaction vessel, and the reaction vessel was placed under an argon atmosphere and dissolved with stirring. The reaction vessel was placed in an environment at a temperature of-60 ℃ to-90 ℃, preferably-78 ℃, butyllithium (7.5mL, 1.6M) was slowly dropped and the reaction was maintained for 1 hour to obtain a reaction solution. Wherein the molecular structure of the fourth compound comprises the following structure:

in the molecular structural formula, X and Y are halogen elements, and R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

The fifth compound (10mmol, 2.22g) was dissolved in tetrahydrofuran (20mL) and slowly dropped into the reaction solution also in an environment at a temperature of-60 ℃ to-90 ℃, preferably-78 ℃. After the completion of the dropwise addition, the reaction solution was warmed to room temperature and reacted for 12 hours. And after the reaction is finished, adding a proper amount of ammonium chloride to quench the reaction to obtain a third solution. Removing the liquid in the third solution by rotation to obtain the third compound. Wherein the molecular structural formula of the fifth compound has an anthracene structure.

Specifically, the fourth compound is 1-bromo-3' -chloro-4-tert-butyl biphenyl, and the fifth compound is 9, 9-dimethyl anthrone. The preparation flow of the third compound is shown as formula 4:

step S20) preparing a first compound: the molecular structural formula of the first compound comprises the following structures:

wherein X in the molecular structural formula is a halogen element, R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

Specifically, the step of preparing the first compound comprises the following steps:

step S21) synthesizing a second target: the third compound obtained in step S10 is placed in a reaction vessel, and concentrated hydrochloric acid (5mL) and glacial acetic acid (15mL) are added and reacted at a temperature of 50 to 100 ℃, preferably 80 ℃, for 24 hours to obtain a second solution. The second solution has a second target substance produced by the reaction.

Step S22) extracting a second target: after the second solution was cooled to room temperature, it was poured into ice water, and an aqueous sodium bicarbonate solution (1M) was added to neutralize the acidic solution in the second solution by sodium bicarbonate. Then, extraction was repeated three times using methylene chloride, and the extract obtained by the three-time extraction was washed three times with water, followed by drying using anhydrous sodium sulfate. And filtering and concentrating the dried extract to obtain the second target substance.

Step S23) purifying the second target: the organic material was separated and purified by 200-300 mesh silica gel column chromatography using petroleum ether and dichloromethane (volume ratio 5:1) as eluent to give about 3.95g of the first compound in 88% yield.

Specifically, the preparation flow of the first compound is shown as formula 5:

step S30) synthesizing a first target: the first compound (2.25g, 5mmol), the second compound (1.61g, 5mmol), t-BuONa (8mmol, 0.76g) and toluene (30mL) were placed in a reaction vessel and deoxygenated by passing nitrogen through the vessel. Then tris (dibenzylideneacetone) dipalladium (0.09mmol,81mg) and tri-tert-butylphosphine tetrafluoroborate (0.92mmol,0.24g) were added and reacted sufficiently at a temperature of 100 ℃ to 130 ℃, preferably at 110 ℃ to obtain a first solution. The first solution has a first target of the reaction synthesis therein. Wherein the second compound comprises at least one aryl or heteroaryl group in its molecular structure.

Step S40) purifying the first target: and cooling the first solution to room temperature, and concentrating the first solution to obtain the first target. Then, the organic material in the first target was separated and purified by 200-300 mesh silica gel column chromatography to obtain about 3.16g of the hole transport material with a yield of 86%.

Specifically, the second compound is di-4-phenyl-aniline. The preparation flow of the hole transport material is shown as the formula 6

The arylamine introduced into the hole transport material provided by the embodiment of the invention can effectively improve the hole injection and transport performances of the organic material, thereby improving the electron and hole balance of an electroluminescent device and achieving lower voltage and higher efficiency. And the introduction of an alkyl, aryl or heteroaryl structure at the 4-position of fluorene can adjust the evaporation temperature, melting or sublimation characteristics, mobility and the like of the material, thereby being beneficial to the stability of mass production evaporation and improving the performance of devices.

Example 3

The embodiment of the invention provides a hole transport material, wherein a main chain in a molecular structural formula of the hole transport material is a spiroanthracene fluorene structure, and the molecular structural formula is as follows:

wherein Ar is₁、Ar₂、Ar₃And Ar₄Comprising at least one aryl or heteroaryl group; r is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of the heteroaryl groups of (a); r₁-R₆Are respectively hydrogen, deuterium and C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C₁-C₆₀At least one of heteroaryl; a. b, c and d are integers less than 5.

Specifically, in the embodiment of the present invention, the molecular structure of Ar1 is:

and R is₉And R₁₀Is an aryl structure or a heteroaryl structure, and L has the structure:

the structure of R is as follows:

a to d are all 0, and R₁-R₆Are all hydrogen bonds.

Specifically, the molecular structural formula of the hole transport material is as follows:

the embodiment of the invention also provides a preparation method of the hole transport material, which comprises the following preparation steps:

step S10) preparing a third compound: the molecular structural formula of the third compound comprises the following structure:

wherein X in the molecular structural formula is a halogen element, R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

Specifically, the step of preparing the third compound comprises the following steps:

the fourth compound (11mmol,3.43g) and tetrahydrofuran (20mL) were added to a reaction vessel, and the reaction vessel was placed under an argon atmosphere and dissolved with stirring. The reaction vessel was placed in an environment at a temperature of-60 ℃ to-90 ℃, preferably-78 ℃, butyllithium (7.5mL, 1.6M) was slowly dropped and the reaction was maintained for 1 hour to obtain a reaction solution. Wherein the molecular structure of the fourth compound comprises the following structure:

in the molecular structural formula, X and Y are halogen elements, and R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

The fifth compound (10mmol, 2.22g) was dissolved in tetrahydrofuran (20mL) and slowly dropped into the reaction solution also in an environment at a temperature of-60 ℃ to-90 ℃, preferably-78 ℃. After the completion of the dropwise addition, the reaction solution was warmed to room temperature and reacted for 12 hours. And after the reaction is finished, adding a proper amount of ammonium chloride to quench the reaction to obtain a third solution. Removing the liquid in the third solution by rotation to obtain the third compound. Wherein the molecular structural formula of the fifth compound has an anthracene structure.

Specifically, the fourth compound is 1-bromo-3' -chloro-4-phenyl biphenyl, and the fifth compound is 9, 9-dimethyl anthrone. The preparation flow of the third compound is shown as the formula 7:

step S20) preparing a first compound: the molecular structural formula of the first compound comprises the following structures:

wherein X in the molecular structural formula is a halogen element, R is C₁-C₆₀Alkyl of (C)₁-C₆₀Aryl or C of₁-C₆₀At least one of heteroaryl groups of (a).

Specifically, the step of preparing the first compound comprises the following steps:

step S21) synthesizing a second target: the third compound obtained in step S10 is placed in a reaction vessel, and concentrated hydrochloric acid (5mL) and glacial acetic acid (15mL) are added and reacted at a temperature of 50 to 100 ℃, preferably 80 ℃, for 24 hours to obtain a second solution. The second solution has a second target substance produced by the reaction.

Step S22) extracting a second target: after the second solution was cooled to room temperature, it was poured into ice water, and an aqueous sodium bicarbonate solution (1M) was added to neutralize the acidic solution in the second solution by sodium bicarbonate. Then, extraction was repeated three times using methylene chloride, and the extract obtained by the three-time extraction was washed three times with water, followed by drying using anhydrous sodium sulfate. And filtering and concentrating the dried extract to obtain the second target substance.

Step S23) purifying the second target: the organic material was separated and purified by 200-300 mesh silica gel column chromatography using petroleum ether and dichloromethane (volume ratio 4:1) as eluent to give about 4.31g of the first compound in 92% yield.

Specifically, the preparation flow of the first compound is shown as formula 8:

step S30) synthesizing a first target: the first compound (2.35g, 5mmol), the second compound (2.88g, 5.5mmol), tetrahydrofuran (10mL) and an aqueous solution of sodium carbonate (5mL, 1.6M) were placed in a reaction vessel and deoxygenated by passing nitrogen gas through the vessel. Then tetrakis (triphenylphosphine) palladium (0.24g, 0.2mmol) was added and reacted at 50 deg.C-100 deg.C, preferably 80 deg.C, for 24 hours to obtain a first solution. The first solution has a first target of the reaction synthesis therein. Wherein the second compound comprises at least one aryl or heteroaryl group in its molecular structure.

Step S40) extracting the first target: after the first solution was cooled to room temperature, it was repeatedly extracted three times with dichloromethane, and the extract obtained by the three extractions was washed three times with water, followed by drying with anhydrous sodium sulfate. And filtering and spin-drying the dried extract to obtain the first target substance.

Step S50) purifying the first target: the organic material was separated and purified by 200-300 mesh silica gel column chromatography using petroleum ether and dichloromethane (volume ratio 5:1) as eluent to give about 3.78g of a hole transport material in a yield of 91%.

Specifically, the second compound is 4- [ bis- (4-phenyl) -amino ] -phenylboronate. The preparation flow of the hole transport material is shown as a formula 9

In the embodiment of the present invention, the structures of L in the molecular structural formula of the hole transport material are respectively:

however, in other embodiments of the present invention, the structure of L may also be one of the following structures:

the arylamine introduced into the hole transport material provided by the embodiment of the invention can effectively improve the hole injection and transport performances of the organic material, thereby improving the electron and hole balance of an electroluminescent device and achieving lower voltage and higher efficiency. And the introduction of an alkyl, aryl or heteroaryl structure at the 4-position of fluorene can adjust the evaporation temperature, melting or sublimation characteristics, mobility and the like of the material, thereby being beneficial to the stability of mass production evaporation and improving the performance of devices.

Application examples

This example is an application of the hole transport materials prepared in examples 1-3 above, which are used in electroluminescent devices.

As shown in fig. 1, the present embodiment provides an electroluminescent device, which includes a substrate layer 1, a first electrode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, an electron transport layer 7, an electron injection layer 8, and a second electrode 9.

The substrate layer 1 is a glass substrate layer and is used for protecting the whole structure of the electroluminescent device. The first electrode 2 is arranged on the substrate layer 1 and is made of Indium Tin Oxide (ITO). The first electrode 2 is used for transmitting current and voltage and providing holes. The hole injection layer 3 is disposed on a surface of the first electrode 2 away from the substrate layer 1, the surface is made of HATCN (hexanitrile hexaazatriphenylene) and has a thickness of 10nm, and the hole injection layer 3 is configured to inject holes inside the hole injection layer into the light emitting layer 6. The hole transport layer 4 is disposed on a surface of the hole injection layer 3 away from the first electrode 2, the hole transport layer is made of the hole transport material, the thickness of the hole transport layer is 40nm, and the hole transport layer 4 is used for transporting holes in the hole injection layer 3 to the light emitting layer 6. The electron blocking layer 5 is arranged on one surface of the hole transport layer 4 far away from the hole injection layer 3, is made of 4,4' -tris (carbazole-9-yl) triphenylamine (TCTA) and has a thickness of 20nm, and the electron blocking layer 5 is used for blocking electrons in the light emitting layer 6 from entering the hole transport layer 4. The light-emitting layer 6 is arranged on one surface of the electron blocking layer 5, which is far away from the hole transport layer 4, the material of the light-emitting layer is tris (2-phenylpyridine) iridium, the thickness of the light-emitting layer is 30nm, and holes provided by the first electrode 2 and electrons provided by the second electrode 9 are gathered in the light-emitting layer 6 and combined under the action of current and voltage, so that electric energy is converted into light energy, and electroluminescence is realized. The electron transport layer 7 is disposed on a surface of the light emitting layer 6 away from the electron blocking layer 5, is made of 1,3, 5-tris (3- (3-pyridyl) phenyl) benzene (TM3PyPB), and has a thickness of 10nm, and the electron transport layer 7 is used for transporting electrons in the electron injection layer 8 into the light emitting layer 6. The electron injection layer 8 is arranged on one surface of the electron transport layer 7 far away from the light emitting layer 6, and is made of B-Phen with the thickness of 40 nm. The second electrode 9 is disposed on a surface of the electron injection layer 8 away from the electron transport layer 7, and is made of lithium fluoride and aluminum, and the second electrode 9 is used for transporting current and voltage and providing electrons.

To better illustrate the performance of the hole transport materials of the present invention, performance tests were performed on electroluminescent devices made from the hole transport materials prepared in examples 1-3. The performance data of the electroluminescent devices produced from the hole transport materials of examples 1 to 3 are shown in Table 1. Among them, the device 1 was made of the hole transport material prepared in example 1, the device 2 was made of the hole transport material prepared in example 2, and the device 3 was made of the hole transport material prepared in example 3. The test mainly detects the highest occupied molecular orbital (LUMO), Highest Occupied Molecular Orbital (HOMO), lowest triplet energy level (T1), voltage, highest current efficiency, and maximum external quantum efficiency.

TABLE 1

As can be seen from Table 1, the hole transport material of the present invention has excellent light emitting performance, and the hole transport layer made of the material has better hole injection and transport performance, and can achieve higher external quantum efficiency with lower voltage, thereby achieving higher light emitting efficiency and better stability.

In other application embodiments of the present invention, the hole transport material can also be used for preparing a hole injection layer.

In embodiments 1 to 3 of the present invention, R in the molecular structural formula of the hole transport material has the following structures:

however, in other embodiments of the present invention, R may also have the following structure:

in other embodiments of the present invention, the molecular structural formula of the hole transport material may also be one of the following structural formulas:

the preparation method is similar to the embodiment of the present invention, and therefore, redundant description is not provided herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.