阅读说明：本技术 芴类化合物及其制备方法和有机电致发光器件 (Fluorene compound, preparation method thereof and organic electroluminescent device ) 是由 汪康 孙向南 王进政 刘昌� 金虎勇 李文军 马晓宇 于 2019-09-26 设计创作，主要内容包括：本发明涉及一种芴类化合物及其制备方法和有机电致发光器件,属于发光材料领域。所述芴类化合物,其结构式如下：<Image he="509" wi="571" file="DDA0002216624240000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>本发明提供的芴类化合物作为空穴传输层制备的有机电致发光器件表现出高的效率及长寿命。本发明提供的芴类化合物的制备方法,其原料易得、制法简单、产率高,适用于工业化生产。(The invention relates to a fluorene compound, a preparation method thereof and an organic electroluminescent device, belonging to the field of luminescent materials. The fluorene compound has the following structural formula: the fluorene compound provided by the invention is used as a cavityThe organic electroluminescent device prepared by the transmission layer has high efficiency and long service life. The preparation method of the fluorene compound provided by the invention has the advantages of easily available raw materials, simple preparation method and high yield, and is suitable for industrial production.)

1. A fluorene compound is characterized by having a structural formula as follows:

in the formula, Ar₁And Ar₂Each independently is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylamino group, a substituted or unsubstituted arylamino group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted fused ring aryl group, or a substituted or unsubstituted heteroaryl group;

R₁、R₂、R₃、R₄each independently selected from hydrogen, or an isotope of hydrogen.

R₅、R₆、R₇Each independently selected from hydrogen, an isotope of hydrogen, halogen, cyano, carboxyl, nitro, hydroxyl, sulfonic acid group, phosphoric acid group, boryl, substituted or unsubstituted silyl, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylamino, substituted or unsubstituted arylamino, substituted or unsubstituted aryloxy, or substituted or unsubstituted arylthio;

R₅、R₆、R₇the position of the substituent is any position of the benzene ring, R₅、R₆The number of (2) is 0 to 4, R₇The number of (2) is 0 to 5, and R₅、R₆、R₇And not both hydrogen or isotopes of hydrogen.

2. The fluorene-based compound according to claim 1, wherein Ar is Ar₁And Ar₂Each independently is a substituted or unsubstituted phenyl group having 6 to 25 carbon atoms or a substituted or unsubstituted fused ring aryl group having 10 to 25 carbon atoms.

3. The fluorene-based compound according to claim 1, wherein Ar is Ar₁And Ar₂Each independently is a substituted or unsubstituted phenyl group having 6 to 18 carbon atoms or a substituted or unsubstituted fused ring aryl group having 10 to 14 carbon atoms.

4. The fluorene-based compound according to claim 1, wherein Ar is Ar₁And Ar₂Each independently is a substituted or unsubstituted phenyl group having 6 to 12 carbon atoms or a substituted or unsubstituted fused ring aryl group having 14 carbon atoms.

5. The fluorene-based compound according to claim 1, wherein Ar is Ar₁And Ar₂Each independently naphthyl, phenanthryl, phenyl, methylphenyl, dimethylphenyl, terphenyl, biphenyl, p-9-phenyl-fluorenyl-9-ylphenyl, or 9,9 diphenyl-9H-fluorenyl.

6. The fluorene-based compound according to claim 1, wherein R is₅、R₆、R₇Each independently selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, phenyl, biphenyl, or naphthyl.

7. The fluorene-based compound according to claim 1, which is any one of the following structures:

8. a method for preparing a fluorene compound according to any one of claims 1 to 7, comprising the steps of:

synthesis of Compound C

Adding compound B and tetrahydrofuran solvent sequentially to a reaction vessel, cooling the vessel to-78 ℃ under a nitrogen atmosphere; then n-butyllithium was added dropwise to the mixture; after stirring the mixture at-78 ℃ for 30 minutes, it was stirred at room temperature for 3 hours and cooled to-78 ℃; thereafter, compound a dissolved in tetrahydrofuran was added dropwise to the mixture; after the addition, the reaction temperature was allowed to warm to room temperature and the mixture was stirred for 16 hours; after the reaction was completed, an aqueous ammonium chloride solution was added to the reaction solution to complete the reaction, and the reaction solution was extracted with ethyl acetate, and the concentrated product after drying the organic layer with magnesium sulfate was purified by column chromatography to obtain compound C;

synthesis of target Compound

Adding the compound C, the compound D and dichloromethane into a reaction container, and fully replacing air with nitrogen for three times; dropwise adding boron trifluoride diethyl etherate dissolved in dichloromethane into the mixture, and reacting at room temperature; after the reaction is finished, extracting the organic matters by dichloromethane and water, drying the organic layer by magnesium sulfate, and purifying the concentrated product by column chromatography to obtain a target compound; the synthetic route is as follows:

in the formula, Ar₁、Ar₂、R₁～R₇The same as the above range; hal is halogen; r₈And R₁～R₄The ranges are the same.

9. An organic electroluminescent device prepared from the fluorene-based compound according to any one of claims 1 to 7.

10. The organic electroluminescent device according to claim 9, wherein the fluorene-based compound is used as a hole transport layer material.

Technical Field

The invention relates to the field of luminescent materials, in particular to a fluorene compound, a preparation method thereof and an organic electroluminescent device.

Background

In order to improve the luminance, efficiency and lifetime of organic electroluminescent devices, a multilayer structure is generally used in the devices. These multilayer structures include a light-emitting layer and various auxiliary organic layers such as a hole injection layer, a hole transport layer, an electron transport layer, and the like. The auxiliary organic layers have the functions of improving the injection efficiency of carriers (holes and electrons) between interfaces of each layer and balancing the transmission of the carriers between the layers, so that the brightness and the efficiency of the device are improved. The hole transport layer is used for enhancing the hole transport capability of the device and blocking electrons in the light-emitting layer, so that the recombination probability of the electrons and the holes is improved.

A substance having a high hole mobility is developed for the reference hole transport layer in order to reduce the driving voltage, and a substance having a high assembly density HOMO valence close to the HOMO valence of the light emitting layer is developed for increasing the hole mobility. The hole mobility is faster than the electron mobility, and the phenomenon of electron imbalance occurs, and the phenomenon of reduction in luminous efficiency and lifetime finally occurs.

Since the hole mobility is reduced by using a material having a low packing density, the driving voltage is increased due to the low packing density when adjusting the electron balance in the light emitting layer, and the lifetime of the device is reduced due to the increase in the driving voltage and the increase in electron heating, the development of a material having a high packing density and an excellent hole trapping ability is strongly required.

Disclosure of Invention

The invention aims to improve the luminous efficiency, stability and service life of a display device, and further provides a fluorene compound with a novel structure, a preparation method thereof and an organic electroluminescent device.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

the invention provides a fluorene compound, which has the following structural formula:

in the formula, Ar₁And Ar₂Each independently is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylamino group, a substituted or unsubstituted arylamino group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted fused ring aryl group, or a substituted or unsubstituted heteroaryl group;

R₁、R₂、R₃、R₄each independently selected from hydrogen, or an isotope of hydrogen.

R₅、R₆、R₇Each independently selected from hydrogen, an isotope of hydrogen, halogen, cyano, carboxyl, nitro, hydroxyl, sulfonic acid group, phosphoric acid group, boryl, substituted or unsubstituted silyl, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylamino, substituted or unsubstituted arylamino, substituted or unsubstituted aryloxy, or substituted or unsubstituted arylthio;

R₅、R₆、R₇the position of the substituent is any position of the benzene ring, R₅、R₆The number of (2) is 0 to 4, R₇The number of (2) is 0 to 5, and R₅、R₆、R₇And not both hydrogen or isotopes of hydrogen.

In the above-mentioned technical solutions, Ar is preferred₁And Ar₂Each independently is a substituted or unsubstituted phenyl group having 6 to 25 carbon atoms or a substituted or unsubstituted fused ring aryl group having 10 to 25 carbon atoms.

In the above-mentioned technical solutions, Ar is preferred₁And Ar₂Each independently is a substituted or unsubstituted phenyl group having 6 to 18 carbon atoms or a substituted or unsubstituted condensed ring having 10 to 14 carbon atomsAnd (4) an aryl group.

In the above-mentioned technical solutions, Ar is preferred₁And Ar₂Each independently is a substituted or unsubstituted phenyl group having 6 to 12 carbon atoms or a substituted or unsubstituted fused ring aryl group having 14 carbon atoms.

In the above-mentioned technical solutions, Ar is preferred₁And Ar₂Each independently naphthyl, phenanthryl, phenyl, methylphenyl, dimethylphenyl, terphenyl, biphenyl, p-9-phenyl-fluorenyl-9-ylphenyl, or 9,9 diphenyl-9H-fluorenyl.

In the above technical scheme, R₅、R₆、R₇Each independently preferably selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, phenyl, biphenyl, or naphthyl.

In the above technical scheme, the fluorene compound is any one of the following structures:

the invention also provides a preparation method of the fluorene compound, which comprises the following steps:

synthesis of Compound C

Adding compound B and tetrahydrofuran solvent sequentially to a reaction vessel, cooling the vessel to-78 ℃ under a nitrogen atmosphere; then n-butyllithium was added dropwise to the mixture; after stirring the mixture at-78 ℃ for 30 minutes, it was stirred at room temperature for 3 hours and cooled to-78 ℃; thereafter, compound a dissolved in tetrahydrofuran was added dropwise to the mixture; after the addition, the reaction temperature was allowed to warm to room temperature and the mixture was stirred for 16 hours; after the reaction was completed, an aqueous ammonium chloride solution was added to the reaction solution to complete the reaction, and the reaction solution was extracted with ethyl acetate, and the concentrated product after drying the organic layer with magnesium sulfate was purified by column chromatography to obtain compound C;

synthesis of target Compound

Adding the compound C, the compound D and dichloromethane into a reaction container, and fully replacing air with nitrogen for three times; dropwise adding boron trifluoride diethyl etherate dissolved in dichloromethane into the mixture, and reacting at room temperature; after the reaction is finished, extracting the organic matters by dichloromethane and water, drying the organic layer by magnesium sulfate, and purifying the concentrated product by column chromatography to obtain a target compound; the synthetic route is as follows:

in the formula, Ar₁、Ar₂、R₁～R₇The same as the above range; hal is halogen, preferably bromine; r₈And R₁～R₄The ranges are the same.

The invention also provides an organic electroluminescent device prepared from the fluorene compound provided by the invention.

In the above technical scheme, the fluorene compound is used as a hole transport layer material.

The invention has the beneficial effects that:

the fluorene compound provided by the invention is used as a hole transport layer to prepare an organic electroluminescent device which has high efficiency and long service life.

The preparation method of the fluorene compound provided by the invention has the advantages of easily available raw materials, simple preparation method and high yield, and is suitable for industrial production.

Detailed Description

[ Synthesis example 1]

Synthesis of Compound C-2

After bromobenzene (60mmol) and 200mL of tetrahydrofuran were charged in the reaction vessel, the vessel was cooled to-78 ℃ under a nitrogen atmosphere. N-butyllithium (2.5M, 60mmol) was then slowly added dropwise to the mixture. After stirring the mixture at-78 ℃ for 30 minutes, it was stirred at room temperature for 3 hours and cooled to-78 ℃. Thereafter, compound A-2(60mmol) dissolved in 200mL of tetrahydrofuran was slowly added dropwise to the mixture. After the addition, the reaction temperature was slowly warmed to room temperature, and the mixture was stirred for 16 hours. Then, an aqueous ammonium chloride solution was added to the reaction solution to complete the reaction, and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried using magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain Compound C-2(19.2g, 78%, MW: 410.22).

After compound C-2(45mmol), intermediate D-2(46mmol) and 500mL of dichloromethane were added to the reaction vessel, the atmosphere was sufficiently replaced with nitrogen three times. Boron trifluoride diethyl etherate (46mmol) dissolved in 100mL of dichloromethane was slowly added dropwise to the mixture. After stirring the mixture at room temperature for 2 hours, it was quenched with distilled water, and the mixture was extracted with dichloromethane. The extracted organic layer was then dried over sodium sulfate and the solvent was removed using a rotary evaporator. Purifying the remaining material by column chromatography to obtain Compound 2

(27.61g，86％，MW:713.42)。

[ Synthesis example 2]

Synthesis of Compound 23

Using 9-fluorenone (60mmol), intermediate B-23(60mmol), n-butyllithium (2.5M, 60mmol), and 200mL of tetrahydrofuran, compound C-23(13.33g, 74%, MW:300.10) was obtained according to the synthesis method for compound C-2 in Synthesis example 1.

Using compound C-23(44mmol), intermediate D-23(45mmol), boron trifluoride diethyl etherate (45mmol) dissolved in 100mL of dichloromethane, 600mL of dichloromethane, compound 23(26.46g, 85%, MW:707.39) was obtained according to the synthesis method with compound 2 in the synthesis example.

[ Synthesis example 3]

Synthesis of Compound 28

Using 200mL of 7-phenyl-9-fluorenone (60mmol), intermediate B-28(60mmol), n-butyllithium (2.5M, 60mmol), and tetrahydrofuran, according to the synthesis method of compound C-2 in Synthesis example 1, compound C-28(16.25g, 72%, MW:376.10) was obtained.

Using compound C-28(40mmol), intermediate D-28(42mmol), boron trifluoride diethyl etherate (42mmol) dissolved in 100mL of dichloromethane, 600mL of dichloromethane, compound 28(25.76g, 81%, MW:795.21) was obtained according to the synthesis method with compound 2 in the synthesis example.

[ Synthesis example 4]

Synthesis of Compound 50

Using intermediate A-50(60mmol), intermediate B-50(60mmol), n-butyllithium (2.5M,

60mmol), 200mL of tetrahydrofuran was synthesized according to the method for synthesizing the compound C-2 of Synthesis example 1 to obtain the compound C-50(24.5g 77% MW: 530.20).

Using compound C-50(45mmol), intermediate D-50(46mmol), boron trifluoride diethyl etherate (46mmol) dissolved in 100mL of dichloromethane, 600mL of dichloromethane, compound 50(33.96g, 83%, MW:909.25) was obtained according to the synthesis method with compound 2 in the synthesis example.

[ Synthesis example 5]

Synthesis of Compound 56

Using 200mL of 9-fluorenone A-56(60mmol), bulk cumene B-56(60mmol), n-butyllithium (2.5M, 60mmol), and tetrahydrofuran, according to the synthesis method of compound C-2 in Synthesis example 1, Compound C-56(15.1g 80% MW:314.25) was obtained

Using compound C-56(45mmol), intermediate D-56(46mmol), boron trifluoride diethyl etherate (46mmol) dissolved in 100mL of dichloromethane, 600mL of dichloromethane, compound 56(33.96g, 83%, MW:909.25) was obtained according to the synthesis method with compound 2 in the synthesis example.

[ Synthesis example 6]

Synthesis of Compound 61

Using 200mL of fluorenone A-61(60mmol), bulk cumene B-61(60mmol), n-butyllithium (2.5M, 60mmol), and tetrahydrofuran, according to the synthesis method of compound C-2 in Synthesis example 1, compound C-61(16.48g 77% MW:356.65) was obtained.

Using compound C-61(45mmol), intermediate D-61(46mmol), boron trifluoride diethyl etherate (46mmol) dissolved in 100mL of dichloromethane, 600mL of dichloromethane, compound 61(31.2g, 80%, MW:866.65) was obtained according to the synthesis method with compound 2 in the synthesis example.

Preparation of organic electroluminescent device and evaluation example of performance

[ example 1 ]: green organic electroluminescent device (hole transport layer)

The compound synthesized in the synthesis example of the invention is used as a hole material, and an organic electroluminescent device is prepared by adopting a common method. Firstly, N1- (naphthalene-2-yl) -N4, N4-bis (4- (naphthalene-2-yl (phenyl) amino) phenyl) -N1-phenyl benzene-1, 4-diamine ("2-TNATA") is evaporated on an ITO (anode) to have a thickness of 60nm, and then the compound synthesized by the invention is evaporated to have a thickness of 260 nm, a host substance 4,4'-N, N' -dicarbazole-biphenyl ("CBP") and a doping substance tris (2-phenylpyridine) iridium ("Ir (ppy)3") are mixed and evaporated to have a thickness of 30nm, a hole blocking layer ("BALq")10nm, an Alq3"40nm, an electron injection layer LiF0.2nm and a cathode Al 150nm according to a weight ratio of 90:10 to form the organic electroluminescent device.

[ example 2] - [ example 6] Green organic electroluminescent device (hole transport layer)

An organic electroluminescent device was produced in the same manner as in example 1, except that the substance described in table 1 was used as a hole transporting material instead of compound 2 in example 1.

Comparative example 1 [ comparative example 3]

An organic electroluminescent device was produced in the same manner as in example 1, wherein [ comparative example 1] was used instead of compound 2, comparative example 2 was used instead of compound 2, and [ comparative example 3] was used instead of compound 2.

Examples 1 to 6 of the present invention, comparative examples 1 to 3, and the organic electroluminescent devices prepared in the comparative examples were biased and then tested for electroluminescent characteristics (EL) at 5000cd/m using PR-650 from Photoresearch corporation²Life equipment test T95 prepared with Mcscience at baseline brightness. The measurement results are shown in Table 1.

TABLE 1

From the results of table 1 above, it can be confirmed that the organic electroluminescent device using the fluorene-based compound provided by the present invention as a hole material exhibits high efficiency and shows a long life, particularly: the fluorene compound of the present invention is suitable for use in a hole layer, and has significantly improved efficiency and life compared to comparative compound 1 (NPB).

The above description is for simplicity of explanation, and the application of the present invention is not limited to the above examples, and it is obvious to those skilled in the art that modifications and variations can be made within the scope of the above description, and all such modifications and variations are intended to fall within the scope of the claims. In the following description, the scope of the present disclosure is not limited to the embodiments described in the embodiments. The scope of the present invention must be interpreted within the scope of the following claims, and all techniques that are equivalent to the scope of the present invention are included in the scope of the claims.