阅读说明：本技术 一类含菲并咪唑的蓝色有机半导体材料及其制备方法与应用 (Phenanthroimidazole-containing blue organic semiconductor material and preparation method and application thereof ) 是由 唐本忠 王志明 张翰 于 2020-06-28 设计创作，主要内容包括：本发明公开了一类含菲并咪唑的蓝色有机半导体材料及其制备方法与应用。该含菲并咪唑的有机半导体材料,结构如下所示：<Image he="534" wi="700" file="DDA0002558611710000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,R1与R2不同,R1为给电子基团或吸电子基团,R2为大空间位阻基团；Ar1与Ar2可以相同,也可以不同,Ar1、Ar2为聚集诱导发光型基团。本发明通过在菲并咪唑上连接上不同的修饰基团,调控菲并咪唑衍生物的激发态性质,使该有机半导体材料固态下具有蓝色或深蓝色发射,且具有显著的聚集诱导发光性能。本发明所制备的有机半导体材料可作为发光层使用,兼具高效固态发光和高电激发激子利用率的特征,从而得到光电性能优异、结构简单、成本低廉的蓝光有机电致发光器件,可在有机电致发光领域有广泛的应用。(The invention discloses a phenanthroimidazole-containing blue organic semiconductor material, and a preparation method and application thereof. The structure of the organic semiconductor material containing the phenanthroimidazole is shown as follows: wherein R1 is different from R2, R1 is an electron donating group or an electron withdrawing group, and R2 is a large steric hindrance group; ar1 and Ar2 can be the same or different, and Ar1 and Ar2 are aggregation-induced emission groups. According to the invention, different modification groups are connected to the phenanthroimidazole so as to regulate and control the excited state property of the phenanthroimidazole derivative, so that the organic semiconductor material is in a solid stateHas blue or deep blue emission and has remarkable aggregation-induced emission performance. The organic semiconductor material prepared by the invention can be used as a luminescent layer and has the characteristics of high-efficiency solid-state luminescence and high-electric excitation exciton utilization rate, so that a blue-light organic electroluminescent device with excellent photoelectric property, simple structure and low cost is obtained, and the blue-light organic electroluminescent device can be widely applied to the field of organic electroluminescence.)

1. A phenanthroimidazole-containing blue organic semiconductor material is characterized in that the chemical structural formula is as follows:

r1 is an electron donating group or an electron withdrawing group, R₂Is a bulky sterically hindered group; ar (Ar)₁And Ar₂May be the same or different, Ar₁、Ar₂Is an aggregation-induced emission type group.

2. The phenanthroimidazole-containing blue organic semiconductor material as claimed in claim 1, wherein R is₁Is one of the following structures 1-6:

3. the phenanthroimidazole-containing blue organic semiconductor material as claimed in claim 1, wherein R is₂Is one of the following structures 7-15:

4. the phenanthroimidazole-containing blue organic semiconductor material as claimed in claim 1, wherein Ar is₁、Ar₂Is one of the following a-k structures:

5. a process for preparing a phenanthroimidazole-containing blue organic semiconductor material according to any one of claims 1 to 4, which comprises the following steps:

using 2, 7-dibromo phenanthrene-9, 10-diketone, 4-tert-butyl aniline and a compound containing R₁、R₂Benzaldehyde and ammonium acetate of substituent groups are used as raw materials, and an intermediate is obtained through one-step ring closing; then with Ar₁、Ar₂And carrying out Suzuki reaction on corresponding boric acid or boric acid ester to obtain the phenanthroimidazole-containing blue organic semiconductor material.

6. The method according to claim 5, wherein the molar ratio of the 2, 7-dibromophenanthrene-9, 10-dione to the 4-tert-butylaniline is 1:4.5-1: 5.5.

7. The method for preparing phenanthroimidazole-containing blue organic semiconductor material according to claim 5, wherein the 2, 7-dibromophenanthrene-9, 10-dione and R-containing compound₁、R₂The molar ratio of the substituted benzaldehyde is 1: 1.

8. The method according to claim 5, wherein the molar ratio of the 2, 7-dibromophenanthrene-9, 10-dione to ammonium acetate is 1:3.5-1: 4.5.

9. Use of the phenanthroimidazole-containing blue organic semiconductor material according to any one of claims 1 to 4 in the preparation of an organic electroluminescent device.

Technical Field

The invention belongs to the technical field of organic photoelectric materials, and particularly relates to a phenanthroimidazole-containing blue organic semiconductor material, and a preparation method and application thereof.

Background

The Organic Light Emitting Diode (OLED) has the characteristics of low driving voltage, high response speed, high luminous efficiency, wide color gamut, Light weight, thinness, flexible folding and the like, and has wide application prospect in the fields of flat panel display and solid illumination; among them, organic light emitting materials have attracted extensive attention in academia and industry as a core technology of OLEDs. At present, compared with the development of mature green light and red light materials, the electroluminescent device prepared by the blue light material with one of three primary colors still has the defects of insufficient efficiency, poor stability and the like. How to screen out a blue light material system with high efficiency and low cost gradually becomes the focus of attention of scientists in various countries.

Excellent blue-emitting materials need to possess three characteristics: high color purity blue emission, high solid state luminous efficiency, and high electron excitation exciton utilization. And the excellent blue light color purity can be well realized by selecting a proper blue light construction element. However, the conventional organic fluorescent material usually has high-brightness luminescence in a single-molecule state, but the phenomenon of fluorescence weakening or even complete disappearance occurs along with the molecular Aggregation, and the Aggregation-quenching (ACQ) effect makes the solid-state luminescence efficiency of the organic fluorescent material lower, which is not favorable for the preparation of high-efficiency OLEDs. In addition, in OLEDs based on conventional fluorescent materials, only 25% of singlet excitons can be used for light emission, while 75% of triplet excitons are white dissipated in a non-radiative form, resulting in low device efficiency; although the Thermal Activation Delayed Fluorescence (TADF) material developed by professor Adachi at kyushu university of japan can fully utilize singlet and triplet excitons formed by electric excitation, the design concept is not favorable for the material to realize the emission of blue light, especially deep blue light, so the blue TADF material is also slow to develop, and the blue TADF device also has the troublesome problems of large roll-off, short lifetime and the like.

The phenanthroimidazole has the characteristics of large conjugation degree, good thermal stability, easy structure modification, bipolar transmission and the like, and is a typical construction element of a blue organic semiconductor material. Aggregation-induced emission (AIE) is a subversion of the traditional concept reported in the tangkui topic group 2001, and refers to a phenomenon in which a molecule hardly emits light in a single-molecule state, and the light emission is significantly enhanced in an aggregated state or under a solid film. The proposal of AIE provides a new idea for solving the ACQ problem of luminescent materials. Subsequently, more and more AIE organic light emitting materials with high solid state light emission were developed and have shown advantages in high brightness, low roll-off, undoped OLED devices. To solve the problem that 75% of triplet excitons in an OLED device cannot be utilized, 2011 proposes a new mechanism that can also fully utilize singlet and triplet excitons, namely a "thermal exciton" mechanism, in the light subject group, and the design concept of the mechanism is not in conflict with the material for realizing blue light emission. In addition, the blue light OLED device prepared based on the thermal exciton material can rapidly utilize triplet excitons, and has the advantages of low roll-off and good stability. However, although the above strategies can solve the problems faced by blue light materials separately, how to combine them organically to optimize the device still does not find a good solution.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a phenanthroimidazole-containing blue organic semiconductor material, and a preparation method and application thereof.

The invention aims to provide a phenanthroimidazole-containing blue organic semiconductor material system aiming at overcoming the defects in the prior art. The luminescent material has blue light emission and AIE characteristics, and has weak luminescence in a dilute solution, but the luminescence is obviously enhanced in an aggregation state or a solid state; the luminescent material also has the characteristic of 'heat exciton', and can break through the exciton utilization rate limit of 25% of the fluorescent material; the material has the characteristics of high solid-state luminous efficiency and high utilization rate of the electrically excited excitons, and can prepare a non-doped blue organic electroluminescent device with high efficiency and low efficiency roll-off.

The invention also aims to provide a preparation method of the phenanthroimidazole-containing blue organic semiconductor material. The method has the advantages of simple process, easily obtained raw materials and high yield.

The invention further aims to provide application of the phenanthroimidazole-containing blue organic semiconductor material in the field of organic electroluminescence, in particular application in preparing a light-emitting layer of an organic light-emitting diode.

The purpose of the invention is realized by at least one of the following technical solutions.

The invention provides a phenanthroimidazole-containing blue organic semiconductor material, which has a chemical structural formula as follows:

wherein R is₁And R₂In a different sense, R₁Is an electron donating group or an electron withdrawing group, R₂Is a bulky sterically hindered group; ar (Ar)₁And Ar₂Ar1 and Ar2 may be the same or different and are aggregation-induced emission groups.

Said R₁Is one of the following structures 1-6:

said R₂Is one of the following structures 7-15:

ar is₁、Ar₂Is one of the following a-k structures:

the invention provides a method for preparing a phenanthroimidazole-containing blue organic semiconductor material, which comprises the following steps:

with 2, 7-dibromophenanthrene-9, 10-dione, 4-tert-butylaniline and R₁、R₂The benzaldehyde of a substituent group is taken as a raw material, and a corresponding intermediate is obtained through one-step ring closing; then with Ar₁And Ar₂And carrying out Suzuki reaction on corresponding boric acid or boric acid ester to obtain the corresponding phenanthroimidazole-containing blue organic semiconductor material.

Further, the molar ratio of the 2, 7-dibromo phenanthrene-9, 10-diketone to the 4-tert-butyl aniline is 1:4.5-1: 5.5.

Further, the 2, 7-dibromo phenanthrene-9, 10-diketone and the compound containing R₁、R₂The molar ratio of the substituted benzaldehyde is 1: 1.

Further, the molar ratio of the 2, 7-dibromo phenanthrene-9, 10-dione to the ammonium acetate is 1:3.5-1: 4.5.

According to the invention, phenanthroimidazole is selected as a building element of the material, so that the material can emit blue fluorescence; by connecting blue light AIE groups to the 2 and 7 positions of the phenanthroimidazole, the AIE characteristic is introduced on the premise of ensuring the blue light emission of the material, so that the material cannot cause fluorescence quenching phenomenon due to strong pi-pi interaction in an aggregation state, and high solid-state luminous efficiency is obtained; in addition, an electron donating group or an electron withdrawing group is connected to the para position of the C2 substituted benzene of the phenanthroimidazole, and a charge transfer excited state is introduced, so that the utilization of triplet excitons is facilitated; the ortho position of C2 substituted benzene of phenanthroimidazole is connected with large steric hindrance group so as to regulate and control the distribution of excited state energy level and make triplet state exciton be utilized by means of "thermal exciton" channel; therefore, the material of the invention has the characteristics of AIE and 'thermal exciton' while emitting blue fluorescence, thereby realizing high solid-state luminous efficiency and high utilization rate of electrically excited excitons. Based on the material, a non-doped blue organic electroluminescent device with high efficiency and low efficiency roll-off can be prepared, and the material has wide application prospect in the field of organic electroluminescence.

The organic semiconductor material can avoid the problem of fluorescence quenching in an aggregation state on the premise of ensuring blue light emission, breaks through the limit of 25 percent of exciton utilization rate of the organic fluorescent material, has simple and efficient synthesis method and excellent thermal stability and electrochemical stability, can be synthesized and purified on a large scale, and has great application prospect.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the phenanthroimidazole-containing blue organic semiconductor material has the characteristics of AIE and 'hot electron', has the characteristics of blue light emission, high solid-state luminous efficiency and high electric excitation exciton utilization rate, and can be used for preparing a high-efficiency low-degree-efficiency roll-off non-doped organic electroluminescent device;

(2) the phenanthroimidazole-containing blue organic semiconductor material disclosed by the invention is simple in synthesis method, easy in raw material obtaining, high in yield and stable in structure;

(3) the phenanthroimidazole-containing blue organic semiconductor material is used for a light-emitting layer of an organic light-emitting diode, has excellent comprehensive performance and can be widely applied to the fields of organic electroluminescence and the like.

Drawings

FIG. 1a is the photoluminescence spectrum of the phenanthroimidazole-containing blue organic semiconductor material in example 1 tested in tetrahydrofuran/water solution in different ratios;

FIG. 1b shows photoluminescence spectra of the phenanthroimidazole-containing blue organic semiconductor material in example 2 tested in tetrahydrofuran/water solutions at different ratios;

FIG. 1c shows photoluminescence spectra of the phenanthroimidazole-containing blue organic semiconductor material in example 3 in tetrahydrofuran/water solutions at different ratios;

FIG. 1d is the photoluminescence spectrum of the phenanthroimidazole-containing blue organic semiconductor material in example 4 tested in tetrahydrofuran/water solution in different ratios;

FIG. 2a is a J-V-L diagram of an undoped OLEDs prepared from the phenanthroimidazole-containing blue organic semiconductor material in example 1;

FIG. 2b is a graph showing the efficiency of undoped OLEDs fabricated from the phenanthroimidazole-containing blue organic semiconductor material in example 1 as a function of luminance;

FIG. 3a is a J-V-L diagram of an undoped OLEDs prepared from the phenanthroimidazole-containing blue organic semiconductor material in example 2;

FIG. 3b is a graph showing the efficiency of undoped OLEDs fabricated from the phenanthroimidazole-containing blue organic semiconductor material in example 2 as a function of luminance;

FIG. 4a is a J-V-L graph of an undoped OLEDs prepared from the phenanthroimidazole-containing blue organic semiconductor material in example 3;

FIG. 4b is a graph showing the efficiency of undoped OLEDs fabricated from the phenanthroimidazole-containing blue organic semiconductor material in example 3 as a function of luminance;

FIG. 5a is a J-V-L graph of an undoped OLEDs prepared from the phenanthroimidazole-containing blue organic semiconductor material in example 4;

FIG. 5b is a graph of the efficiency as a function of the luminance of undoped OLEDs produced from the phenanthroimidazole-containing blue organic semiconductor material of example 4.

Detailed Description

The following examples are presented to further illustrate the practice of the invention, but the practice and protection of the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available by commercial purchase.