阅读说明：本技术 一种不对称的吲哚衍生物核小分子受体材料及其制备方法 (Asymmetric indole derivative nuclear small molecule receptor material and preparation method thereof ) 是由 高锋 曹佳民 于 2021-08-16 设计创作，主要内容包括：本发明公开一种不对称的吲哚衍生物核小分子受体材料及其制备方法,涉及有机太阳能电池材料领域。本发明的受体材料的结构通式为：其中Ar～(1),Ar～(2)和Ar～(3)为独立的芳香基团,R～(1)为C-(1)-C-(20)的烷基,R～(2)为C-(2)-C-(12)的烷基或烷基芳香基。本发明的小分子受体材料以吲哚衍生物为核,具有不对称的化学结构,与现有的具有双螺结构ITIC类小分子受体材料相比,本发明涉及的小分子受体材料具有单螺结构,表现出显著红移的吸收光谱,提高了对太阳光的利用率；能显著提高有机太阳能电池的光电流；应用于太阳能电池时具有能量转换效率高的优点。(The invention discloses an asymmetric indole derivative nuclear small molecule receptor material and a preparation method thereof, relating to the field of organic solar cell materials. The structural general formula of the receptor material is as follows: wherein Ar is 1 ，Ar 2 And Ar 3 Is an independent aromatic radical, R 1 Is C 1 ‑C 20 Alkyl of R 2 Is C 2 ‑C 12 Alkyl or alkylaryl group. The micromolecule receptor material of the invention takes indole derivatives as the nucleus, has asymmetric chemical structure, and compared with the existing ITIC micromolecule receptor material with double-helix structure, the micromolecule receptor material of the invention has the advantages thatThe single-spiral structure shows a remarkable red-shifted absorption spectrum, and the utilization rate of sunlight is improved; the photocurrent of the organic solar cell can be obviously improved; the solar cell has the advantage of high energy conversion efficiency when applied to a solar cell.)

1. An asymmetric indole derivative nuclear small molecule receptor material has a single spiro structure, and the structural general formula is as follows:

in the general formula (I), Ar¹Is one of the following structural units:

R³is H, or C₁-C₂₀Alkyl groups of (a);

Ar²is one of the following structural units:

Ar³is one of the following structural units:

R¹is C₁-C₂₀Alkyl groups of (a);

R²is C₂-C₁₂Or one having the following structural unit:

wherein R is⁴Is C₂-C₁₂Alkyl group of (1).

2. The asymmetric indole derivative nuclear small molecule receptor material according to claim 1, wherein:

when Ar is¹Is composed ofR³Is C₁₁Alkyl of Ar²Is composed ofAr³Is composed ofR¹Is C₆Alkyl of R²Is composed ofR⁴Is C₆When the alkyl group is substituted, the structural general formula of the small molecule acceptor material is as follows:

3. the method for preparing asymmetric indole derivative nuclear small molecule receptor material according to claim 1, wherein the preparation of the compound of the general formula (I) comprises the following steps:

the method comprises the following steps: carrying out Suzuki coupling reaction on the compound of the general formula (a) and the compound of the general formula (III) to obtain a compound of a general formula (b);

step two: reacting a compound of formula (b) with a compound of formula (IV) in an organic solvent to give a compound of formula (c);

step three: carrying out a ring closing reaction on the compound of the general formula (c) to obtain a compound of a general formula (d);

step four: subjecting a compound of formula (d) to a formylation reaction to obtain a compound of formula (e);

step five: performing a Kenaokuer condensation reaction on a compound of a general formula (e) and a compound of a general formula (V) to obtain a compound of a general formula (I);

4. the production method according to claim 3, characterized in that: in the first step, in a protective atmosphere, putting the compound of the general formula (a), the compound of the general formula (III), toluene, ethanol and potassium carbonate mixed solution into a reactor, adding palladium tetrakis (triphenylphosphine), refluxing, cooling, pouring into water, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain the compound of the general formula (b).

5. The production method according to claim 3, characterized in that: and in the second step, in a protective atmosphere, adding n-butyllithium into the compound of the general formula (IV) and tetrahydrofuran under the condition of a cooling bath, stirring, adding the compound of the general formula (b), heating to room temperature, stirring, extracting with dichloromethane, washing with water, and removing the solvent to obtain the compound of the general formula (c).

6. The production method according to claim 3, characterized in that: in the third step, the compound of the general formula (c), the ion exchange resin Amberlyst 15 and toluene are put into a reactor in a protective atmosphere, refluxed, cooled to room temperature, filtered, removed of the solvent, purified by column chromatography to obtain the compound of the general formula (d).

7. The production method according to claim 3, characterized in that: and in the fourth step, in a protective atmosphere, putting the compound with the general formula (d), 1, 2-dichloroethane and DMF into a reactor, adding phosphorus oxychloride in an ice-water bath, stirring, refluxing, cooling, adding an aqueous solution, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain the compound with the general formula (e).

8. The production method according to claim 3, characterized in that: and fifthly, adding the compound of the general formula (e), the compound of the general formula (V) and chloroform into a reactor in a protective atmosphere, adding pyridine, refluxing, cooling, precipitating with methanol, separating and purifying to obtain the compound of the general formula (I).

9. A process according to claim 2, wherein the preparation of the compound of formula (II) comprises the steps of:

the method comprises the following steps: adding a compound 1, 2-bromothiophene-3-ethyl formate, and a mixed solution of toluene, ethanol and potassium carbonate into a reactor, adding tetrakis (triphenylphosphine) palladium under the protection of argon, refluxing for 24 hours, cooling, pouring into water, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain a compound 2;

step two: adding 1- (4-bromophenyl) hexane and tetrahydrofuran into a reactor, dropwise adding n-butyllithium at the temperature of-78 ℃ under the protection of argon, stirring for 1h, adding a compound 2, slowly heating to room temperature, stirring overnight, extracting with dichloromethane, washing with water, removing a solvent by spinning, and drying to obtain a compound 3;

step three: adding the compound 3, the ion exchange resin Amberlyst 15 and toluene into a reactor, carrying out reflux reaction for 6 hours under the protection of argon, cooling to room temperature, filtering, removing the solvent by spinning, and purifying by column chromatography to obtain a compound 4;

step four: adding a compound 4, 1, 2-dichloroethane and DMF (dimethyl formamide) into a reactor, adding phosphorus oxychloride dropwise at 0 ℃ under the protection of argon, stirring at room temperature for 1h, refluxing for 24h, cooling, adding water, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain a compound 5;

step five: sequentially adding the compound 5, 6-difluoro-3- (dicyanomethylene) indone and chloroform into a reactor, adding pyridine under the protection of nitrogen, heating to reflux for 24 hours, cooling, precipitating with methanol, and purifying by column chromatography to obtain a compound (II);

10. the application of the asymmetric indole derivative nuclear small molecule acceptor material according to any one of claims 1-9 in an organic solar cell.

Technical Field

The invention relates to the field of organic solar cells, in particular to an asymmetric indole derivative nuclear small molecule receptor material and a preparation method thereof.

Background

Solar energy is an inexhaustible clean energy, and a solar cell can directly convert the solar energy into electric energy, so that the solar cell becomes an important way and an effective method for solving the energy crisis and promoting carbon neutralization. The organic solar cell, as a third-generation solar cell, can be used for producing and preparing flexible devices in a convenient and low-cost manner such as film coating, ink-jet printing and the like, and becomes one of the current research hotspots. Compared with the traditional fullerene derivative receptor material, the small molecule receptor material has the following outstanding advantages: 1) the molecules are easy to design, and the synthesis cost is low; 2) the light absorption performance is good in visible light and even near infrared region; 3) the molecular energy level is easy to adjust; 4) good shape stability and the like. In 2015, the A-D-A type small molecule receptor material ITIC is reported for the first time in the Xiaowei subject group, and the breakthrough result promotes the rapid development of the small molecule receptor material. The highest energy conversion efficiency of the organic solar cell based on the small molecule receptor breaks through 18% at present, and is nearly near to commercial production.

The ITIC is taken as a classical A-D-A type micromolecule receptor material, and has a double-helix structure, and a push-pull electronic structure formed by a middle electron-donating core and a terminal strong electron-withdrawing group is beneficial to charge transfer in molecules and widening of an absorption range. In order to further improve the energy conversion efficiency, it is important to widen the absorption spectrum and to improve the photocurrent. Therefore, in order to achieve the purpose, it is important to provide a small molecule receptor material of an indole derivative core for enhancing the electron donating ability of the small molecule receptor core, so as to further broaden the absorption spectrum and improve the photocurrent and energy conversion efficiency, thereby solving the disadvantages in the prior art.

Disclosure of Invention

The invention aims to provide an asymmetric indole derivative nuclear small molecule receptor material.

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

an asymmetric indole derivative nuclear small molecule receptor material, which has an asymmetric single spiro chemical structure, takes an indole derivative as a core, and has a structural general formula as follows:

in the general formula (I), Ar¹Is one of the following structural units:

R³is H, or C₁-C₂₀Alkyl groups of (a);

Ar²is one of the following structural units:

Ar³is one of the following structural units:

R¹is C₁-C₂₀Alkyl groups of (a);

R²is C₂-C₁₂Or one having the following structural unit:

wherein R is⁴Is C₂-C₁₂Alkyl group of (1).

The invention also aims to provide a preparation method of the asymmetric indole derivative nuclear small molecule receptor material, which comprises the following steps:

the method comprises the following steps: carrying out Suzuki coupling reaction on the compound of the general formula (a) and the compound of the general formula (III) to obtain a compound of a general formula (b);

step two: reacting a compound of a general formula (b) with a compound of a general formula (IV) in an organic solvent to obtain a compound of a general formula (c);

step three: carrying out a ring closing reaction on the compound of the general formula (c) to obtain a compound of a general formula (d);

step four: performing formylation reaction on the compound of the general formula (d) to obtain a compound of a general formula (e);

step five: performing a Kenaokuer condensation reaction on a compound with a general formula (e) and a compound with a general formula (V) to obtain a compound with a general formula (I);

therefore, the invention provides the asymmetric indole derivative nuclear micromolecule receptor material, the absorption spectrum of the asymmetric indole derivative nuclear micromolecule receptor material is obviously red-shifted compared with the existing similar molecules without nitrogen atoms, such as ITIC and IT-4F, and the asymmetric indole derivative nuclear micromolecule receptor material can effectively widen the light absorption range and improve the energy conversion efficiency when being applied to the organic solar cell.

Preferably, in the first step, in a protective atmosphere, the compound of the general formula (a), the compound of the general formula (III), toluene, ethanol and potassium carbonate mixed solution is placed in a reactor, and then tetrakis (triphenylphosphine) palladium is added, refluxed, cooled, poured into water, extracted with dichloromethane, and subjected to spin-off of a solvent, and column chromatography purification to obtain the compound of the general formula (b).

More preferably, the toluene is purified treated toluene.

Preferably, in the second step, n-butyllithium is added to the compound of the general formula (IV) and tetrahydrofuran in an argon atmosphere under cooling bath conditions, the mixture is stirred, the compound of the general formula (b) is added, the mixture is heated to room temperature and stirred overnight, dichloromethane is used for extraction, the mixture is washed with water, and the solvent is removed, so that the compound of the general formula (c) is obtained.

More preferably, the tetrahydrofuran is anhydrous treated tetrahydrofuran; the n-butyl lithium is dropwise added. Preferably, in the third step, the compound of the general formula (c), the ion exchange resin Amberlyst 15 and toluene are put into a reactor in an argon atmosphere, and the reflux reaction, the cooling to room temperature, the filtration, the solvent removal and the column chromatography purification are carried out to obtain the compound of the general formula (d).

More preferably, the toluene is purified treated toluene.

Preferably, in the fourth step, the compound of the general formula (d), 1, 2-dichloroethane and DMF are placed in a reactor in an argon atmosphere, phosphorus oxychloride is added under an ice-water bath, stirring, refluxing, cooling, then adding an aqueous solution, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain the compound of the general formula (e).

More preferably, the reaction mixture is stirred at room temperature for 1 hour before refluxing.

Preferably, step five: and (3) sequentially adding the compound of the general formula (e), the compound of the general formula (V) and chloroform into a reactor, adding pyridine under the protection of nitrogen, heating to reflux reaction, cooling, precipitating with methanol, and purifying by column chromatography to obtain the compound of the general formula (II).

More preferably, the reflux time is 24 h.

Another object of the present invention is to provide an asymmetric indole derivative nuclear small molecule receptor material having a chemical structure of general formula (II):

the preparation method of the asymmetric indole derivative nuclear small molecule receptor material comprises the following steps:

the method comprises the following steps: adding a compound 1, 2-bromothiophene-3-ethyl formate and a mixed solution of toluene, ethanol and potassium carbonate into a reactor, adding palladium tetrakis (triphenylphosphine) under the protection of argon, refluxing for 24 hours, cooling, pouring into water, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain a compound 2;

step two: adding 1- (4-bromophenyl) hexane and tetrahydrofuran into a reactor, dropwise adding n-butyllithium at-78 ℃ under the protection of argon, stirring for 1h, adding a compound 2, slowly heating to room temperature, stirring overnight, extracting with ethyl acetate, washing with water, removing a solvent by rotation, and drying to obtain a compound 3;

step three: adding the compound 3, the ion exchange resin Amberlyst 15 and toluene into a reactor, carrying out reflux reaction for 6 hours under the protection of argon, cooling to room temperature, filtering, removing the solvent by spinning, and purifying by column chromatography to obtain a compound 4;

step four: adding a compound 4, 1, 2-dichloroethane and DMF (dimethyl formamide) into a reactor, adding phosphorus oxychloride dropwise at 0 ℃ under the protection of argon, stirring at room temperature for 1h, refluxing for 24h, cooling, adding water, extracting with dichloromethane, removing a solvent by spinning, and purifying by column chromatography to obtain a compound 5;

step five: sequentially adding the compound 5, 6-difluoro-3- (dicyanomethylene) indone and chloroform into a reactor, adding pyridine under the protection of nitrogen, heating to reflux for 24 hours, cooling, precipitating with methanol, and purifying by column chromatography to obtain a compound (II);

the invention further aims to provide an application of the asymmetric indole derivative nuclear small molecule acceptor material in an organic solar cell.

The invention has the beneficial effects that:

the invention provides an asymmetric indole derivative nuclear micromolecule receptor material, a preparation method and application thereof, wherein the receptor material has a structural general formula as follows:

wherein Ar is¹，Ar²And Ar³Is an independent aromatic radical, R¹Is C₁-C₂₀Alkyl of R²Is C₂-C₁₂Alkyl or alkylaryl group. Compared with the prior art, the invention has the following characteristics:

1. an asymmetric single spiro chemical structure with indole derivatives;

2. an absorption spectrum with a significant red-shift;

3. the absorption range is greatly widened, and the utilization rate of the organic solar cell to sunlight is improved;

4. the short-circuit current of the organic solar cell is obviously improved;

5. the energy conversion efficiency of the organic solar cell is improved.

Drawings

The invention is further illustrated by means of the attached drawings, the examples of which are not to be construed as limiting the invention in any way.

FIG. 1 is a chloroform diluted solution (10) of the receptor material TITT-2FIC prepared in example 1^-5M) and absorption spectrum in thin film state;

FIG. 2 is a plot of cyclic voltammetry for the receptor material TITT-2FIC prepared in example 1;

FIG. 3 is a J-V curve of an organic solar cell prepared by blending the acceptor material TITT-2FIC and the donor material PBDB-T prepared in example 1;

FIG. 4 is an EQE spectrum of an organic solar cell prepared by blending the receptor material TITT-2FIC and the donor material PBDB-T prepared in example 1.

Detailed Description

The invention is further described with reference to the following examples.

Example 1:

the preparation method of the asymmetric indole derivative nuclear small molecule receptor material TITT-2FIC comprises the following specific steps:

(1) synthesis of Compound 2: a100 mL single-neck reaction flask was charged with Compound 1(800mg,1.34mmol), ethyl 2-bromothiophene-3-carboxylate (376mg,1.6mmol), 15mL toluene, 10mL ethanol, 10mL aqueous potassium carbonate (2M), and 56mg Pd (PPh)₃)₄. And (5) refluxing and reacting for 24h under the protection of Ar. Cooling, separating, extracting with dichloromethane and MgSO₄Drying, filtering, removing solvent by rotation, column chromatography separation, petroleum ether/dichloromethane (7:3) as eluent, 583mg of orange yellow solid (yield: 70.1%) are obtained.¹HNMR(CDCl₃,500MHz,δ/ppm):7.70(d,J＝8.2Hz,1H),7.57(s,1H),7.54(d,J＝5.4Hz,1H),7.33(d,J＝8.2,1H),7.25(d,J＝5.4Hz,1H),7.02(s,1H),4.36(t,J＝7.3Hz,2H),4.20(q,J＝7.1Hz,2H),2.78(t,J＝7.7Hz,2H),1.97-1.91(m,2H),1.85-1.79(m,2H),1.45-1.42(m,4H),1.30-1.27(br,18H),1.17(t,J＝7.1Hz,3H),0.90-0.85(m,6H)。

(2) Synthesis of Compound 3: a100 mL single-neck reaction flask was charged with 1- (4-bromophenyl) hexane (1.05g,4.35mmol) and 20mL anhydrous THF. Ar protection, n-BuLi (2.7mL,1.6M) was added dropwise at-78 deg.C, after 1h of reaction at-78 deg.C, 18mL of Compound 2(0.90g, 1.45mmol) in THF was added and the reaction was allowed to proceed overnight at room temperature. Pouring into water, extracting with dichloromethane, MgSO₄Drying, filtering and removing the solvent to obtain the compound 3, and directly carrying out the next reaction without purification.

(3) Synthesis of Compound 4: a100 mL single-mouth reaction flask is added with the compound 3 obtained in the previous step, 40mL anhydrous toluene, 500mg ion exchange resin Amberlyst 15 and refluxed for 6h under the protection of Ar. Cooled to room temperature, filtered, the solvent removed by evaporation, and the crude product purified by column chromatography using petroleum ether as eluent to yield 468mg of a brown solid (yield: 39.2%).¹H NMR(CDCl₃,500MHz,δ/ppm):7.58(d,J＝14.7Hz,1H),7.41(d,J＝10.3Hz,1H),7.25-7.22(m,1H),7.19-7.17(m,4H),7.04-7.02(m,5H),6.95(s,1H),4.37-4.31(m,2H),2.53(t,J＝7.8Hz,4H),1.96-1.92(m,2H),1.73-1.67(m,2H),1.59-1.53(m,6H),1.48-1.43(m,3H),1.38-1.26(m,32H),0.90-0.85(m,12H)。

(4) Synthesis of Compound 5: in a 100mL two-neck flask, compound 4(468mg,0.57mmol), 30mL of 1, 2-dichloroethane, 1.5mL of DMF and Ar protection are added, phosphorus oxychloride (0.54mL,5.8mmol) is added dropwise at 0 ℃, the mixture is stirred for 1h at room temperature and refluxed for 24 h. After cooling to room temperature, Na was added₂CO₃Extracting with dichloromethane in water solution, washing with saturated brine, drying with anhydrous sodium sulfate, removing solvent by rotary extraction, purifying the crude product by column chromatography with petroleum ether/dichloromethane (7:3) as eluent to obtain 322mg of red solid (yield: 61.2%).¹H NMR(CDCl₃,500MHz,δ/ppm):10.09(s,1H),9.84(s,1H),7.68(d,J＝4.5Hz,2H),7.57(s,1H),7.17(d,J＝8.2Hz,4H),7.07(d,J＝8.1Hz,4H),4.38(t,J＝7.3Hz,2H),3.12(t,J＝7.6Hz,2H),2.55(t,J＝7.8Hz,4H),1.97-1.91(m,2H),1.87-1.81(m,2H),1.60-1.54(m,6H),1.44-1.25(m,32H),0.89-0.85(m,12H)。

(5) Synthesis of TITT-2 FIC: in a 100mL single-neck flask, compound 5(50mg,0.053mmol), 5, 6-difluoro-3- (dicyanomethylene) indolone (74mg,0.320mmol) and 20mL chloroform were added, 0.5mL pyridine was added under the protection of argon, the mixture was heated to reflux for 24h, cooled to room temperature, added dropwise to 100mL methanol, and the crude product obtained by suction filtration was purified by column chromatography using petroleum ether/dichloromethane (1:1) as an eluent, to give 57mg of a black solid (yield: 79.1%).¹H NMR(CDCl₃,500MHz,δ/ppm):9.05(s,1H),8.74(s,1H),8.60-8.57(m,1H),8.53-8.50(m,1H),7.76-7.69(m,4H),7.27(br,5H),7.16(d,J＝8.1Hz,4H),4.08(br,2H),2.99(br,2H),2.59(t,J＝7.8Hz,4H),1.81(br,2H),1.74-1.71(m,2H),1.56-1.58(m,4H),1.36-1.23(m,34H),0.89-0.83(m,12H).MS(MALDI-TOF,m/z):1362.247.

The ultraviolet-visible absorption spectrum of the receptor material TITT-2FIC prepared in the embodiment 1 in the states of a chloroform dilute solution and a thin film is shown in FIG. 1, the absorption peak of the TIT-2FIC in the solution is 709nm, the absorption peak of the solid film is 761nm, a significant red shift is achieved, the absorption spectrum is widened, and the optical band gap is 1.47 eV. In contrast, the commonly used seven-ring small molecule acceptor material IT-4F has an absorption peak of 727nm and an optical band gap of 1.53 eV. Compared with the micromolecule receptor material IT-4F with a double-helix structure, the asymmetric indole derivative nuclear micromolecule receptor material TITT-2FIC prepared in the embodiment 1 has the absorption peak red-shifted by 34nm, has a remarkably broadened absorption spectrum, and is beneficial to obtaining higher photocurrent and energy conversion efficiency in a device.

The cyclic voltammetry curve of the receptor material TITT-2FIC prepared in this example 1 is shown in FIG. 2, the oxidation potential of TITT-2FIC is 0.81V, the reduction potential is-0.83V, the HOMO and LUMO energy levels of TITT-2FIC are calculated to be-5.61 eV and-3.97 eV, respectively, and the electrochemical band gap is 1.64 eV. The results show that the TITT-2FIC has a suitable energy level, and can be well matched with the energy level of common polymer donor materials.

The receptor material TITT-2FIC prepared in the embodiment 1 is used as a receptor material to prepare an organic solar cell, and the device structure is ITO/PEDOT, PSS/PM6, TITT-2 FIC/PDINO/Al. As shown in FIG. 3, the organic solar cell prepared by blending the acceptor material TITT-2FIC with the commonly used donor material PM6 had an open circuit voltage of 0.885V and a short circuit current of 20.88mA/cm²The fill factor was 66.31%, and the energy conversion efficiency was 12.26%. Fig. 4 is an external quantum efficiency spectrum (EQE) of the corresponding device.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.