Organic light-emitting material, preparation method of organic light-emitting material and light-emitting device

Abstract

The invention provides an organic light-emitting material. The molecular structural formula of the organic light-emitting material is # imgabs0 #. The invention further provides a preparation method of the organic light-emitting material and a light-emitting device applying the organic light-emitting material.

Description

Technical Field

[0001] This application relates to organic light-emitting materials, methods for preparing organic light-emitting materials, and light-emitting devices including such organic light-emitting materials. Background Art

[0002] Among light-emitting materials, the research on organic small-molecule light-emitting materials has attracted increasing attention. They have a wide variety of types, rich colors, and due to their simple structure and easy adjustment, the research has become increasingly extensive. However, compared with inorganic light-emitting materials, most organic small-molecule light-emitting materials are prone to fluorescence quenching under solid or liquid conditions, which limits the application of organic small-molecule light-emitting materials in more fields. Summary of the Invention

[0003] In a first aspect of this application, an organic light-emitting material is provided, and the molecular structural formula of the organic light-emitting material is as follows:

[0004]

[0005] In one embodiment, the absorption spectrum of the organic light-emitting material is 250 nm - 460 nm.

[0006] In one embodiment, the organic light-emitting material emits light in the range of 450 nm - 600 nm when excited by light in the range of 420 nm - 460 nm.

[0007] The organic light-emitting material provided by the embodiments of this application not only has the fluorescence properties of coumarin, but also further increases the π-conjugated system of salicylaldehyde Schiff base, making the organic light-emitting material have higher luminous efficiency and be able to emit light stably under solid or liquid conditions. This organic light-emitting material has great potential in the field of organic light-emitting devices.

[0008] In a second aspect of this application, a method for preparing an organic light-emitting material is provided, including:

[0009] Providing 3,5-ditert-butylsalicylaldehyde and 7-amino-4-(trifluoromethyl)coumarin as reaction raw materials;

[0010] Dissolving the reaction raw materials in an organic solvent for reaction;

[0011] Removing the organic solvent to obtain the organic light-emitting material;

[0012] Wherein, the molecular structural formula of the organic light-emitting material is as follows:

[0013]

[0014] In one embodiment, the molar ratio of the 3,5 - di - tert - butylsalicylaldehyde to the 7 - amino - 4 - (trifluoromethyl)coumarin is 1:0.9 to 1:1.1.

[0015] In one embodiment, the concentration of the 3,5 - di - tert - butylsalicylaldehyde in the organic solvent is 1 - 1.5 mol / L.

[0016] In one embodiment, the organic solvent includes one of ethanol, methanol, toluene, benzene, tetrahydrofuran, and dioxane.

[0017] In one embodiment, the step of dissolving the reaction raw materials in an organic solvent for reaction includes: heating the mixture of the reaction raw materials and the organic solvent to reflux with stirring, and reacting for 2 - 6 h.

[0018] In one embodiment, the step of removing the organic solvent to obtain the organic light - emitting material includes: rotary - evaporating and concentrating the reaction mixture, cooling to - 4°C to 4°C to precipitate crystals, and filtering, washing, and recrystallizing to obtain the organic light - emitting material.

[0019] The third aspect of the present application provides a light - emitting device, including: the above - mentioned organic light - emitting material. Description of the Drawings

[0020] Figure 1 It is the proton nuclear magnetic resonance spectrum of the organic light - emitting material in one embodiment of the present application.

[0021] Figure 2 It is the absorption spectrum of the organic light - emitting material in one embodiment of the present application.

[0022] Figure 3 It is the fluorescence excitation and fluorescence emission spectra of the organic light - emitting material in one embodiment of the present application.

[0023] Figure 4 It is the flow chart of the preparation method of the organic light - emitting material in one embodiment of the present application.

[0024] Description of the Main Component Symbols

[0025] Steps S1, S2, S3

[0026] The following specific embodiments will further illustrate the present application in conjunction with the above - mentioned drawings. Specific Embodiments

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application.

[0028] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0029] To further elaborate on the technical means and effects adopted by this application to achieve the intended purpose, the following provides a detailed description of this application in conjunction with the accompanying drawings and preferred embodiments.

[0030] Schiff bases are a class of organic compounds containing imine or methylimine characteristic groups (-RC=N-), and are usually formed by the condensation of amino groups (-NH2) and active carbonyl groups (C=O). Among many Schiff base compounds, salicylaldehyde Schiff bases are one of the most studied compounds. Currently, the research on salicylaldehyde Schiff bases mainly focuses on the synthesis, crystal structure characterization, biological activity, and optical properties of compounds and their metal complexes.

[0031] Coumarin is one of the earliest discovered substances with fluorescence properties. Many natural and synthetic coumarin derivatives are compounds with strong fluorescence and relatively high fluorescence quantum yields. Among them, amino and hydroxy coumarin derivatives are particularly important because their photophysical characteristics are controlled by intramolecular charge transfer (ICT), which is of great value for the development of applications such as fluorescence sensors based on ICT modulation. In addition, simple amino coumarin and hydroxy coumarin have the characteristics of absorbing and emitting in the ultraviolet / blue spectral region, occupying the emission position with a relatively large quantum yield, and have been used to develop blue dye lasers.

[0032] Fluorine atoms are strong electron-withdrawing groups. The introduction of strong electron-withdrawing groups can regulate the energy level structure, lower the LUMO energy level (the LUMO energy level refers to the energy level of the lowest unoccupied molecular orbital in a molecule, usually used to describe the electron acceptance ability; the LUMO energy level of a receptor is usually lower and has a stronger electron acceptance ability), broaden the bandgap, cause the emission wavelength to blue-shift. In addition, the low LUMO energy level can reduce the potential barrier of electrons, which is beneficial to the injection of device carriers, thereby improving device performance.

[0033] The embodiment of this application provides an organic light-emitting material, and its molecular structural formula is:

[0034]

[0035] The organic light-emitting material is formed by the condensation reaction of salicylaldehyde and aminocoumarin introduced with trifluoromethyl. That is, the organic light-emitting material is formed by the condensation of 3,5-di-tert-butylsalicylaldehyde and 7-amino-4-(trifluoromethyl)coumarin. Among fluorine compounds, compounds containing trifluoromethyl account for a large proportion. Introducing trifluoromethyl into coumarin by an appropriate method is of particular importance for constructing new functional materials.

[0036] This organic light-emitting material not only has the fluorescence properties of coumarin but also further enlarges the π-conjugated system of salicylaldehyde Schiff base, making the organic light-emitting material have a higher luminous efficiency. Introducing trifluoromethyl into the aminocoumarin structure improves the stability of the material, making it more suitable as the core material of organic light-emitting devices. This organic light-emitting material has great potential in the field of organic light-emitting devices.

[0037] Since trifluoromethyl is introduced into the reaction raw material 7-amino-4-(trifluoromethyl)coumarin, trifluoromethyl is also retained in the finally prepared organic light-emitting material. As a strong electron-withdrawing group, fluorine atoms lower the LUMO energy level, broaden the band gap, causing the emission wavelength to blue-shift. In addition, the low LUMO energy level can reduce the potential barrier of electrons, which is beneficial to the injection of device carriers, thereby improving device performance.

[0038] Please refer to Figure 2 and Figure 3 , the absorption spectrum of this organic light-emitting material is 250nm - 460nm, and it emits light at 450nm - 600nm under the excitation of light at 420nm - 460nm. Specifically, this organic light-emitting material can emit blue-green light at 450nm - 600nm under the excitation of light at 420nm - 460nm. Among them, the optimal excitation wavelength of this organic light-emitting material is about 440nm, and the optimal emission wavelength is about 480nm.

[0039] The organic light-emitting material provided in the embodiment of this application is a Schiff base fluorescent material based on coumarin, belonging to organic small molecule light-emitting materials. It has a high fluorescence intensity in both solid and solution states, emits light at 450nm - 600nm under the excitation of light at 420nm - 460nm, and can emit light stably without fluorescence quenching.

[0040] The embodiment of this application also provides a method for preparing an organic light-emitting material. Please refer to Figure 4 , which includes:

[0041] Step S1: Provide 3,5-di-tert-butylsalicylaldehyde and 7-amino-4-(trifluoromethyl)coumarin as reaction raw materials;

[0042] Step S2: Dissolve the reaction raw materials in an organic solvent for reaction;

[0043] Step S3: Remove the organic solvent to obtain the organic light-emitting material.

[0044] The preparation method of the organic light-emitting material can obtain the organic light-emitting material in the above embodiments. The organic light-emitting material has high fluorescence intensity and luminescence stability, and has the potential to be prepared into an organic light-emitting device with good performance.

[0045] In step S1, the molar ratio of 3,5-di-tert-butylsalicylaldehyde to 7-amino-4-(trifluoromethyl)coumarin is 1:0.9 to 1:1.1.

[0046] In step S2, the organic solvent includes one of ethanol, methanol, toluene, benzene, tetrahydrofuran, and dioxane.

[0047] In step S2, the concentration of 3,5-di-tert-butylsalicylaldehyde as a reaction raw material in the organic solvent is 1 to 1.5 mol / L.

[0048] In step S2, the specific steps of dissolving the reaction raw materials in the organic solvent for reaction include: under stirring, heating the mixture of the reaction raw materials and the organic solvent to reflux and reacting for 2 - 6 h.

[0049] In step S2, the reaction formula of 3,5-di-tert-butylsalicylaldehyde and 7-amino-4-(trifluoromethyl)coumarin is as follows:

[0050]

[0051] In step S3, the steps of removing the organic solvent to obtain the organic light-emitting material include: rotary evaporating and concentrating the mixture after the reaction in step S2 to remove part of the organic solvent, then cooling to -4°C to 4°C to precipitate the crystals of the organic light-emitting material, and then performing filtration, washing, and recrystallization to obtain the organic light-emitting material.

[0052] The preparation method of the organic light-emitting material has a simple process, convenient operation, and is convenient for large-scale industrial production. The prepared organic light-emitting material has high fluorescence intensity in both solid and solution states, emits light at 450 nm - 600 nm under the excitation of light at 420 nm - 460 nm, and can emit light stably without fluorescence quenching.

[0053] The embodiment of the present application also provides a light-emitting device, including the organic light-emitting material in the above embodiments. Specifically, the light-emitting device can be one of a lighting lamp, a fluorescence imaging device, or a fluorescence sensor.

[0054] The preparation of the organic light-emitting material will be specifically described below through Examples 1 to 2.

[0055] Example 1

[0056] The preparation method of the organic light-emitting material is as follows:

[0057] 6.09 g of 3,5-di-tert-butylsalicylaldehyde and 5.72 g of 7-amino-4-(trifluoromethyl)coumarin were mixed and dissolved in 25 mL of absolute ethanol. Under stirring, the mixture was heated to reflux for 6 h. Part of the solvent was removed by rotary evaporation until the solution volume was 5 mL. The solution was cooled to 0 °C to precipitate crystals, which were filtered, washed, and recrystallized to obtain the target product with a yield of 86%.

[0058] Example 2

[0059] The preparation method of the organic light-emitting material is as follows:

[0060] 5.86 g of 3,5-di-tert-butylsalicylaldehyde and 5.96 g of 7-amino-4-(trifluoromethyl)coumarin were mixed and dissolved in 25 mL of absolute ethanol. Under stirring, the mixture was heated to reflux for 6 h. Part of the solvent was removed by rotary evaporation until the solution volume was 5 mL. The solution was cooled to 0 °C to precipitate crystals, which were filtered, washed, and recrystallized to obtain the target product with a yield of 85%.

[0061] Example 3

[0062] The preparation method of the organic light-emitting material is as follows:

[0063] 7.02 g of 3,5-di-tert-butylsalicylaldehyde and 6.18 g of 7-amino-4-(trifluoromethyl)coumarin were mixed and dissolved in 20 mL of absolute ethanol. Under stirring, the mixture was heated to reflux for 4 h. Part of the solvent was removed by rotary evaporation until the solution volume was 5 mL. The solution was cooled to 0 °C to precipitate crystals, which were filtered, washed, and recrystallized to obtain the target product with a yield of 82%.

[0064] Example 4

[0065] The preparation method of the organic light-emitting material is as follows:

[0066] 7.02 g of 3,5-di-tert-butylsalicylaldehyde and 7.56 g of 7-amino-4-(trifluoromethyl)coumarin were mixed and dissolved in 25 mL of absolute ethanol. Under stirring, the mixture was heated to reflux for 4 h. Part of the solvent was removed by rotary evaporation until the solution volume was 5 mL. The solution was cooled to 0 °C to precipitate crystals, which were filtered, washed, and recrystallized to obtain the target product with a yield of 85%.

[0067] The 1H NMR spectrum of the organic light-emitting material prepared in Example 1 is as Figure 1 shown. According to Figure 1 the position (chemical shift) and area (number of hydrogen atoms) of the peaks corresponding to the hydrogen atoms, it can be determined that the product prepared in Example 1 corresponds to the molecular structural formula of the organic light-emitting material, verifying that the organic light-emitting material with this molecular structural formula has been formed.

[0068] The organic light-emitting material provided by the embodiments of the present application not only has the fluorescence properties of coumarin, but also further enlarges the π-conjugated system of salicylaldehyde Schiff base, making this material have higher luminous efficiency. Introducing trifluoromethyl group into the aminocoumarin structure can improve the stability of the material, making it more suitable as the core material of organic light-emitting devices. It has high fluorescence intensity both in the solid state and in solution, and can emit light stably without fluorescence quenching phenomenon, making it more suitable as the core material of organic light-emitting devices. Moreover, the preparation process is simple, the operation is convenient, and it is convenient for large-scale industrial production.

[0069] Those of ordinary skill in the art of the present technology should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as within the scope of the substantial spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope of protection required by the present application.

Claims

1. An organic light-emitting material, characterized in that, The molecular structural formula of the organic light-emitting material is as follows:

2. The organic light-emitting material according to claim 1, characterized in that, The absorption spectrum of the organic light-emitting material is 250 nm - 460 nm.

3. The organic light-emitting material according to claim 1, wherein The organic light-emitting material emits light at 450 nm - 600 nm when excited by light at 420 nm - 460 nm.

4. A method for preparing an organic light-emitting material, characterized in that, It includes: Providing 3,5-di-tert-butylsalicylaldehyde and 7-amino-4-(trifluoromethyl)coumarin as reaction raw materials; Dissolving the reaction raw materials in an organic solvent for reaction; Removing the organic solvent to obtain the organic light-emitting material; Wherein, the molecular structural formula of the organic light-emitting material is as follows:

5. The method for preparing an organic light-emitting material according to claim 4, wherein The molar ratio of the 3,5-di-tert-butylsalicylaldehyde to the 7-amino-4-(trifluoromethyl)coumarin is 1:0.9 - 1:1.

1.

6. The method for preparing an organic light-emitting material according to claim 4, wherein The concentration of the 3,5-di-tert-butylsalicylaldehyde in the organic solvent is 1 - 1.5 mol / L.

7. The method for preparing an organic light-emitting material according to claim 4, characterized in that, The organic solvent includes one of ethanol, methanol, toluene, benzene, tetrahydrofuran, and dioxane.

8. The method for preparing an organic light-emitting material according to claim 4, characterized in that, The step of dissolving the reaction raw materials in an organic solvent for reaction includes: heating the mixture of the reaction raw materials and the organic solvent to reflux under stirring and reacting for 2 - 6 h.

9. The method for preparing an organic light-emitting material according to claim 4, wherein The step of removing the organic solvent to obtain the organic light-emitting material includes: rotary evaporating and concentrating the reaction mixture, cooling to -4°C to 4°C to precipitate crystals, filtering, washing, and recrystallizing to obtain the organic light-emitting material.

10. A light-emitting device, characterized in that, It includes: The organic light-emitting material according to any one of claims 1 - 3.

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