阅读说明：本技术 一种具有基于硝基的吸电子基团的化合物、非富勒烯电子受体材料及其制备方法 (Compound with nitro-based electron-withdrawing group, non-fullerene electron acceptor material and preparation method thereof ) 是由 姚闯 杨叶子 于 2020-06-30 设计创作，主要内容包括：本发明公开了一种具有基于硝基的吸电子基团的化合物、非富勒烯电子受体材料及其制备方法。其中,所述具有基于硝基的吸电子基团的化合物具有如下结构：<Image he="317" wi="422" file="DDA0002563498570000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,R1,R2为H、F、Cl、Br、I或-CH<Sub>3</Sub>。本发明提供的具有基于硝基的吸电子基团的化合物中主要官能团为硝基,不含有氰基(－C≡N),因而具有环境友好的优点。采用该化合物制备的非富勒烯电子受体材料,具有比现有非富勒烯电子受体材料更低的LUMO能级和更强的电子亲和势,有利于提高其吸电子能力,提高对太阳能的利用率和对电子的传输性能。(The invention discloses a compound with a nitro-based electron-withdrawing group, a non-fullerene electron acceptor material and a preparation method thereof. Wherein the compound having a nitro-based electron withdrawing group isThe compound has the following structure: wherein R1 and R2 are H, F, Cl, Br, I or-CH 3 . The main functional group in the compound with the electron-withdrawing group based on the nitro group is the nitro group, and the compound does not contain cyano (-C ≡ N), so the compound has the advantage of environmental friendliness. The non-fullerene electron acceptor material prepared by the compound has lower LUMO energy level and stronger electron affinity than the existing non-fullerene electron acceptor material, and is beneficial to improving the electron-withdrawing capability, the utilization rate of solar energy and the transmission performance of electrons.)

1. A compound having a nitro-based electron withdrawing group, comprising an electron withdrawing group of the structure:

wherein R is₁，R₂Is H, F, Cl, Br, I or-CH₃。

2. A non-fullerene electron acceptor material having the structure:

wherein R is₁，R₂Is a hydrogen atom, a halogen substituent, C₁～C₂₀Alkyl of (C)₁～C₂₀Alkoxy, carbonyl or ester groups of (a);

the structure of the T is one of the following structures:

3. use of a compound having a nitro-based electron-withdrawing group, wherein the compound having a nitro-based electron-withdrawing group according to claim 1 or the non-fullerene electron acceptor material according to claim 2 is used for preparing a photoactive layer of a solar cell.

4. A method for preparing a compound having a nitro-based electron withdrawing group, comprising the steps of:

s1, adding 1H-indene-1, 3(2H) -diketone and dichloromethanesulfonyl chloride into a tetrahydrofuran solvent containing triethylamine, stirring for 2 hours at room temperature, extracting with dichloromethane to remove the solvent, drying an organic phase with anhydrous sodium sulfate, and purifying an obtained organic layer by column chromatography to obtain an intermediate product C1; wherein the mol ratio of the 1H-indene-1, 3(2H) -diketone to the dichloromethanesulfonyl chloride to the triethylamine is 1: 1-2: 2-5, wherein the ratio of triethylamine to tetrahydrofuran is 1 mmol: 2-10 mL;

s2, adding C1 to a solution containing MeOH and NH₄Stirring in OH container for 6 hr, extracting with ethyl acetate, drying the organic phase with anhydrous sodium sulfate, removing organic solvent, subjecting the residue to column chromatography with neutral alumina, and eluting with ethanol and ethyl acetate to obtain product C2; wherein, C1 and NH₄The molar ratio of OH to MeOH is 1: 2-5: 500 to 1000;

s3, putting C2 into a container filled with acetonitrile water solution, and sequentially adding K₂CO₃And disodium edetate, acetonitrile and 30% H₂O₂An aqueous solution of, wherein₂CO₃Disodium ethylenediamine tetraacetate, acetonitrile and H₂O₂The molar ratio of the aqueous solution is 1: 0.001 to 0.005: 5-20: 5-20; the reaction mixture was stirred at room temperature for 1 hour, and the resultant mixture was extracted with ethyl acetate to extract an organic layer, dried with anhydrous sodium sulfate, evaporated under vacuum to remove the solvent, filtered through a short silica gel plug, and finally purified by flash column chromatography to obtain the compound EG1 having a nitro-based electron withdrawing group according to claim 1.

5. The method of preparing a compound having a nitro-based electron withdrawing group as claimed in claim 4, wherein the column chromatography uses a mixed solution of ethyl acetate and methanol as an eluent, and the volume ratio of ethyl acetate to methanol is 3: 1.

6. the method of preparing a compound having a nitro-based electron withdrawing group as claimed in claim 4, wherein the column chromatography uses a mixed solution of ethanol and ethyl acetate as an eluent, and the volume ratio of ethyl acetate to ethanol is 3: 1.

7. the method of claim 4, wherein the solution in the short silica gel plug is 10% EtOAc in petroleum ether in step S3.

8. A method for preparing a non-fullerene electron acceptor material according to claim 2, which is mainly obtained by reacting the compound EG1 having a nitro-based electron withdrawing group according to claim 1 with the compound T by Knoevenagel; the specific reaction steps are as follows:

s11, adding the compound T and the compound EG1 into a mixed solution of pyridine and chloroform for dissolving, then reacting for 24 hours at 65 ℃ under the protection of nitrogen and under the reflux condition, cooling to room temperature, introducing the mixture into methanol and filtering; wherein the molar ratio of the compound T to the compound EG1 is 1: 1-10, wherein the volume ratio of pyridine to trichloromethane is 1: 20-100; the molar volume ratio of the compound to the mixed solution is 1 mmol: 200 and 1000 mL;

s12, purifying the filtered residue by silica gel column chromatography with dichloromethane: using petroleum ether as a washing and dehydrating machine to obtain a solid product, namely the non-fullerene electron acceptor material as claimed in claim 2; wherein the dichloromethane: the volume ratio of the petroleum ether is 1: 1.

Technical Field

The invention relates to the technical field of organic solar cells, in particular to a compound with a nitro-based electron-withdrawing group, a non-fullerene electron acceptor material and a preparation method thereof.

Background

The organic solar cell is a solar cell with a core part made of organic materials, and mainly takes organic matters with photosensitive properties as semiconductor materials to generate voltage to form current by a photovoltaic effect. The organic solar cell is a sandwich type electronic device based on a bulk heterojunction structure, an intermediate active layer is a main component for realizing photoelectric conversion and is formed by blending an n-type electron transport material and a p-type hole transport material, the traditional n-type material is a fullerene material, and the improvement of the photovoltaic performance of the fullerene material is greatly limited because the fullerene material has poor absorption in a visible light range, the structure is not easy to adjust and the price is high.

Non-fullerene solar cells have the following advantages over fullerene cells, and thus have become a hotspot in research: (1) the band gap can be tailored high (typically 1.2-2.2eV) to shift the light absorption red to the near infrared region and blue to the blue region. (2) The energy compensation is low (about 0.1 eV), and the charge separation efficiency is high; (3) the open-circuit voltage loss is small (0.5-0.6V), the non-fullerene receptor can remarkably reduce the radiation and non-radiation recombination, and the open-circuit voltage loss is greatly reduced; (4) the non-fullerene acceptor molecule can freely adjust the flatness and the crystallinity, and effectively control the appearance of the blending film of the active layer, thereby improving the stability of the device.

However, most of the electron-withdrawing groups used in the current non-fullerene electron acceptor materials are 1, 1-dicyanomethylene-3-indanone containing a cyano group (-C ≡ N) and derivatives thereof. The compounds may have toxicity, and in the synthesis process, the malononitrile with high toxicity is necessarily used, so that the preparation process is easy to cause harm to operators, is not beneficial to actual industrial production, and is easy to pollute the environment.

Disclosure of Invention

In view of the above-mentioned disadvantages of the prior art, an object of the present invention is to provide a compound having a nitro-based electron withdrawing group, and a non-fullerene electron acceptor material containing the same as a new material for a solar cell. In order to solve the technical problems, the invention adopts the following technical scheme:

a compound having a nitro-based electron withdrawing group, comprising an electron withdrawing group of the structure:

wherein R is₁，R₂Is H, F, Cl, Br, I or-CH₃。

Further provided is a non-fullerene electron acceptor material having the structure:

wherein R is₁，R₂Is a hydrogen atom, a halogen substituent, C₁～C₂₀Alkyl of (C)₁～C₂₀Alkoxy, carbonyl or ester groups of (a); the structure of the T is one of the following structures:

the invention also provides application of the compound with the nitro-based electron withdrawing group or the non-fullerene electron acceptor material in preparing a photoactive layer of a solar cell.

The invention also provides a preparation method of the material, and aims to solve the problems that the non-fullerene electron acceptor material prepared by adopting malononitrile in the prior art is extremely toxic, is easy to cause harm to operators and is not environment-friendly. In order to solve the technical problems, the invention adopts the following technical scheme:

a method for preparing a compound having a nitro-based electron withdrawing group, comprising the steps of:

s1, adding 1H-indene-1, 3(2H) -diketone and dichloromethanesulfonyl chloride into a tetrahydrofuran solvent containing triethylamine, stirring for 2 hours at room temperature, extracting with dichloromethane to remove the solvent, drying an organic phase with anhydrous sodium sulfate, and purifying an obtained organic layer by column chromatography to obtain an intermediate product C1; wherein the mol ratio of the 1H-indene-1, 3(2H) -diketone to the dichloromethanesulfonyl chloride to the triethylamine is 1: 1-2: 2-5, wherein the ratio of triethylamine to tetrahydrofuran is 1 mmol: 2-10 mL;

s2, adding C1 to a solution containing MeOH and NH₄Stirring in OH container for 6 hr, extracting with ethyl acetate, drying the organic phase with anhydrous sodium sulfate, removing organic solvent, subjecting the residue to column chromatography with neutral alumina, and eluting with ethanol and ethyl acetate to obtain product C2; wherein, C1 and NH₄The molar ratio of OH to MeOH is 1: 2-5: 500 to 1000;

s3, putting C2 into a container filled with acetonitrile water solution, and sequentially adding K₂CO₃And disodium edetate, acetonitrile and 30% H₂O₂An aqueous solution of, wherein₂CO₃Disodium ethylenediamine tetraacetate, acetonitrile and H₂O₂The molar ratio of the aqueous solution is 1: 0.001 to 0.005: 5-20: 5-20; the reaction mixture was stirred at room temperature for 1 hour, and the resultant mixture was extracted with ethyl acetate to extract an organic layer, dried with anhydrous sodium sulfate, evaporated under vacuum to remove the solvent, filtered through a short silica gel plug, and finally purified by flash column chromatography to obtain the compound EG1 having a nitro-based electron withdrawing group.

In step S1, the column chromatography uses a mixed solution of ethyl acetate and methanol as an eluent, and the volume ratio of ethyl acetate to methanol is 3: 1. in step S2, the column chromatography uses a mixed solution of ethanol and ethyl acetate as an eluent, and the volume ratio of ethyl acetate to ethanol is 3: 1. in step S3, the solution in the short silica plug was 10% EtOAc in petroleum ether.

The invention also provides a preparation method of the non-fullerene electron acceptor material, which is mainly formed by reacting the compound EG1 with the nitro-based electron-withdrawing group with the compound T through Knoevenagel; the specific reaction steps are as follows:

s11, adding the compound T and the compound EG1 into a mixed solution of pyridine and chloroform for dissolving, then reacting for 24 hours at 65 ℃ under the protection of nitrogen and under the reflux condition, cooling to room temperature, introducing the mixture into methanol and filtering; wherein the molar ratio of the compound T to the compound EG1 is 1: 1-10, wherein the volume ratio of pyridine to trichloromethane is 1: 20-100; the molar volume ratio of the compound to the mixed solution is 1 mmol: 200 and 1000 mL;

s12, purifying the filtered residue by silica gel column chromatography with dichloromethane: using petroleum ether as a washing and dehydrating machine to obtain a solid product, namely the non-fullerene electron acceptor material as claimed in claim 2; wherein the dichloromethane: the volume ratio of the petroleum ether is 1: 1.

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

1. the compound with the electron-withdrawing group based on the nitro group, provided by the invention, has the advantages that the main electron-withdrawing functional group is the nitro group, no cyano group (-C ≡ N) is contained, and the compound is a non-toxic and environment-friendly electron-withdrawing compound and electron acceptor material, so that the compound is environment-friendly.

2. Compared with the existing non-fullerene electron acceptor material, the non-fullerene electron acceptor material provided by the invention has lower LUMO energy level and stronger electron affinity, and is beneficial to improving the electron-withdrawing capability; the solar energy absorption material has strong absorption in visible light and near infrared regions, and can improve the utilization rate of solar energy; the exciton is easy to separate, and the filling factor and the short-circuit current of the device can be effectively improved; meanwhile, the material has higher electron mobility, and is beneficial to improving the transmission performance of electrons.

3. The method for preparing the compound with the nitro-based electron-withdrawing group and the non-fullerene electron acceptor material has the characteristics of simplicity and convenience in operation, easiness in control and the like, does not involve virulent malononitrile in the preparation process, cannot cause harm to operators, can be used for actual industrial production, is environment-friendly, and has good popularization value.

Drawings

FIG. 1 is a scheme for preparing a compound having a nitro-based electron withdrawing group according to the present invention.

FIG. 2 is a 1H NMR (400MHz, CDCl3) nuclear magnetic spectrum of the compound having a nitro-based electron withdrawing group prepared in example 1.

FIG. 3 is a 1H NMR (400MHz, CDCl3) nuclear magnetic spectrum of the non-fullerene electron acceptor material T2 prepared in example 3.

FIG. 4 is an absorption spectrum of Y6.

FIG. 5 is an absorption spectrum of the non-fullerene electron acceptor material T2 prepared in example 3.

FIG. 6 is a 1H NMR (400MHz, CDCl3) nuclear magnetic spectrum of the non-fullerene electron acceptor material T4 prepared in example 4.

Detailed Description

The present invention will be further described with reference to the following examples and accompanying drawings.

A compound having a nitro-based electron withdrawing group, comprising an electron withdrawing group of the formula:

wherein R is₁，R₂Is H, F, Cl, Br, I or-CH₃。

Secondly, a non-fullerene electron acceptor material comprises the following structural formula:

wherein R is₁，R₂Is hydrogen atom, halogen substituent, C1-C20 alkyl, C1-C20 alkoxy, carbonyl or ester group; the structure of the T is one of the following structures: