A-DA 'D-A type non-fullerene small molecule acceptor material based on inner side straight chain alkyl and preparation method and application thereof

Abstract

The invention provides an A-DA 'D-A type non-fullerene small molecule acceptor material based on inner side straight chain alkyl as well as a preparation method and application of the A-DA' D-A type non-fullerene small molecule acceptor material. The A-DA 'D-A type non-fullerene small molecule acceptor material based on inner side straight chain alkyl has a structure as shown in a formula I in the specification. According to the invention, the inner side alkyl chain of the A-DA 'D-A type non-fullerene small molecule receptor is of a straight chain alkyl structure, and the adjustment of the accumulation structure and disorder degree between donor and receptor or receptor molecules in an active layer is realized, so that the light-emitting property of the material and the open-circuit voltage in the performance of a device are improved, the voltage loss in an organic solar cell is reduced, and the organic solar cell has a good application prospect. And finally, the photovoltaic performance of the organic solar device is improved. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of molecular technology, and in particular relates to an A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl, and a preparation method and application thereof. Background Art

[0002] Due to the strong designability of non-fullerene acceptor materials, the performance of organic solar cells has been rapidly improved in recent years. At present, the photoelectric energy conversion efficiency of organic solar cells has exceeded 20%. Among them, the more commonly used high-efficiency materials are ITIC, Y6 and L8-BO. ​​By modifying the structure of these materials, developing more efficient organic photovoltaic materials to further improve the performance of organic solar cells has become the goal of many researchers (L. Zhu, M. Zhang, G. Zhou, Z. Wang, W. Zhong, J. Zhuang, Z. Zhou, X. Gao, L. Kan, B. Hao, F. Han, R. Zeng, X. Xue, S. Xu, H. Jing, B. Xiao, H. Zhu, Y. Zhang, F. Li u, Joule, 2024, 10.1016 / j.joule.2024.08.001; Y. Jiang, S. Sun, R. Xu, F. Liu, X. Miao, G. Ran, K. Liu, Y. Yi, W. Zhang, X. Zhu, Nat. Energy, 2024, 9, 975-986; Y. Sun, L. Wang, C. Guo, J. Xiao, C. Liu, C. Chen, W. Xia, Z. Gan, J. Cheng, J. Zhou, Z. Chen, J. Zhou, D. Liu,T.Wang,W.Li,J.Am.Chem.Soc.,2024,146,12011-12019;J.Yuan,Y.Zhang,L.Zhou,G.Zhang,H.Yip,T.Lau,X.Lu,C.Zhu, H.Peng,PAJohnson,M.Leclerc,Y.Cao,J.Ulanski,Y.Li,Y.Zou,Joule,2019,3,1140-1151;Y.Lin,J.Wang,Z.Zhang,H.Bai,Y. Li, D. Zhu, X. Zhan, Adv. Mater., 2015, 27, 1170-1174; L. Zhu, M. Zhang, J. Xu, C. Li, J. Yan, G. Zhou, W. Zhong, T. Hao, J. Song, X. Xue, Z. Zhou, R. Zeng, H. Zhu, C. Chen, R. C. I. MacKenzie, Y. Zou, J. Nelson, Y. Zhang, Y. Sun, F. Liu, Nat. Mater., 2022, 21, 656-663).

[0003] Among them, the adjustment of the molecular side chain structure is a commonly used molecular modification method. The size of the molecular side chain has a great influence on the changes in the characteristics of the active layer, such as the stacking, disorder and microscopic morphology of the molecules. For example, the organic solar cells based on L8-BO acceptors reported in the literature have a larger side chain connected to the β position of the bithiophene part compared to the classic Y6. Therefore, the use of L8-BO with a larger side chain makes the acceptor molecules in the donor-acceptor blend have better molecular stacking properties, so that the organic solar cells based on D18:L8-BO show a power conversion efficiency of more than 19%, while the power conversion efficiency of organic solar cells based on D18:Y6 is 18.2% (L. Zhu, M. Zhang, J. Xu, C. Li, J. Yan, G. Zhou, W. Zhong, T. Hao, J. Song, X. Xue, Z. Zhou, R. Zeng, H. Zhu, C. Chen, RCI MacKenzie, Y. Zou, J. Nelson, Y. Zhang, Y. Sun, F. Liu, Nat. Mater., 2022, 21, 656-663; J. Yuan, Y. Zhang, L. Zhou, G. Zhang, H. Yip, T. Lau, X. Lu, C. Zhu, H. Peng, PA Johnson, M. Lec lerc,Y.Cao,J.Ulanski,Y.Li,Y.Zou,Joule,2019,3,1140-1151;J.Wang,D.Qian,F.Dong,H.Wu,H. Pan, S. Liang, H. Wu, X. Feng, W. Li, M. Wang, Z. Tang, Z. Ma, Chem. Eng. J., 2023, 465, 142909; Y. Chen, R. Ma, T. Liu, Y. Xiao, H. K. Kim, J. Zhang, C. Ma, H. Sun, F. Bai, X. Guo, K. S. Wu, X. Lu, H. Yan, Adv. Energy Mater., 2021, 11, 2003777; H. Wang, S. Wu, D. Yang, X. Yu, S. Yang, P. Ding, P. Yan, Z. Ma, J. Zhang, Z. Ge, Sci. China Chem., 2024, 67, 2686-2693).Similarly, for ternary organic solar cells, the use of acceptor L8-BO with larger side chains showed improved performance. Organic solar cells based on PM6:D18:L8-BO had a conversion efficiency of 19.6%, while organic solar cells based on PM6:D18:Y6 had a conversion efficiency of only 17.7% (L. Zhu, M. Zhang, J. Xu, C. Li, J. Yan, G. Zhou, W. Zhong, T. Hao, J. Song, X. Xue, Z. Zhou, R. Zeng, H. Zhu, C. Chen, RCI MacKenzie, Y. Zou, J. Nelson, Y. Zhang, Y. Sun, F. Liu, Nat. Mater., 2022, 21, 656-663).

[0004] Therefore, according to the side chain engineering modification method, a new A-DA'DA type non-fullerene small molecule acceptor material is designed to improve the luminescence performance of the material and the open circuit voltage in the device performance, and reduce the voltage loss in the organic solar cell, which is of great significance for improving the photovoltaic performance of the organic solar cell device. For this reason, the present invention is proposed. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides an A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl, and a preparation method and application thereof. The present invention makes the inner alkyl chain of the A-DA'DA type non-fullerene small molecule acceptor a straight-chain alkyl structure, so as to adjust the stacking structure and disorder degree of the donor or acceptor molecules in the active layer, thereby improving the luminescence performance of the material and the open circuit voltage in the device performance, reducing the voltage loss in the organic solar cell, and thus improving the photovoltaic performance of the organic solar device.

[0006] The technical solution of the present invention is as follows:

[0007] An A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group has a structure shown in the following formula I:

[0008]

[0009] Wherein, in Formula I,

[0010] R is C6~C 12 A straight chain alkyl group;

[0011] X is S, O or Se;

[0012] A is an electron-withdrawing group containing active α hydrogen.

[0013] Preferably according to the present invention, A is selected from one of the following structures:

[0014]

[0015] in,

[0016] R1 is C1~C 30 Alkyl, R2 is C1~C 30 of alkyl.

[0017] According to the present invention, the A-DA'DA type non-fullerene small molecule receptor material based on inner linear alkyl has a structure as shown in the following formula I-1:

[0018]

[0019] According to the present invention, the preparation method of the above-mentioned A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl comprises the following steps:

[0020] (1) Compound 1 and compound R-Br are reacted in N,N-dimethylformamide in the presence of potassium carbonate to obtain compound 2;

[0021]

[0022] In compound 1, the substituent X is the same as X in formula Ⅰ; in compound R-Br, the substituent R is the same as R in formula Ⅰ;

[0023] (2) stirring phosphorus oxychloride and N,N-dimethylformamide at 0-5° C., then adding a chloroform solution of compound 2 to react to obtain compound 3;

[0024]

[0025] (3) In chloroform, under the action of pyridine, compound 3 and a compound containing an A unit are reacted to obtain an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group;

[0026] The compound containing A unit is selected from one of the following compounds:

[0027]

[0028] Preferably according to the present invention, the ratio of the volume of N,N-dimethylformamide to the mass of compound 1 in step (1) is 30-100 mL:1 g.

[0029] Preferably according to the present invention, the molar ratio of potassium carbonate to compound 1 in step (1) is 5-20:1.

[0030] Preferably according to the present invention, the molar ratio of the compound R-Br to the compound 1 in step (1) is 3-5:1.

[0031] Preferably, according to the present invention, the reaction temperature in step (1) is 70-90° C., and the reaction time is 10-15 h; the reaction is carried out under a protective gas, and the protective gas is argon or nitrogen.

[0032] Preferably, in step (1), the post-treatment step of the reaction solution obtained by the reaction is as follows: water is added to the obtained reaction solution, and the ratio of the added volume of water to the molar number of compound 1 is 300-500 mL: 1 mmol; then, dichloromethane is used for extraction, and the obtained organic phase is free of solvent to obtain a crude product, and the obtained crude product is purified by silica gel column chromatography to obtain compound 2, and the eluent is dichloromethane: n-hexane = 1:4, v / v.

[0033] Preferably according to the present invention, the ratio of the volume of N,N-dimethylformamide to the mass of phosphorus oxychloride in step (2) is 0.5-1 mL:1 g.

[0034] Preferably, in step (2), the stirring reaction time of phosphorus oxychloride and N,N-dimethylformamide is 1-2 hours.

[0035] Preferably, according to the present invention, the concentration of the chloroform solution of compound 2 in step (2) is 10-20 mg / mL; the molar ratio of phosphorus oxychloride to compound 2 is 55-70:1; the chloroform solution of compound 2 is added at room temperature, and room temperature has a well-known meaning in the art, referring to 25±5°C.

[0036] Preferably, according to the present invention, in step (2), the reaction temperature after adding compound 2 is 60-70°C, and the reaction time is 10-12h; the reaction is carried out under a protective gas, and the protective gas is argon or nitrogen.

[0037] Preferably, in step (2), the post-treatment step of the reaction solution obtained by the reaction is as follows: dichloromethane and water are added to the obtained reaction solution for extraction, the solvent is removed from the obtained organic phase, and the obtained crude product is purified by silica gel column chromatography to obtain compound 3, and the eluent is dichloromethane:n-hexane=1:1, v / v.

[0038] Preferably according to the present invention, the ratio of the volume of chloroform to the mass of compound 3 in step (3) is 50-100 mL:1 g.

[0039] Preferably according to the present invention, the molar ratio of pyridine to compound 3 in step (3) is 10-20:1.

[0040] Preferably according to the present invention, the molar ratio of the compound containing A unit to compound 3 in step (3) is 2-4:1.

[0041] Preferably, according to the present invention, the reaction temperature in step (3) is 65-75° C., and the reaction time is 8-15 h; the reaction is carried out under a protective gas, and the protective gas is argon or nitrogen.

[0042] Preferably, in step (3) of the present invention, the post-treatment step of the reaction solution obtained by the reaction is as follows: the solvent is removed from the obtained reaction solution, and the obtained crude product is purified by silica gel column chromatography, and the eluent is dichloromethane:n-hexane=1.5:1, v / v.

[0043] According to the present invention, the application of the above-mentioned A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl is used as an active layer electron acceptor material for light capture to prepare an organic solar cell.

[0044] The preparation route of the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl of the present invention is as follows:

[0045]

[0046] In the above formula, the substituents R, X, and A are as described above.

[0047] The technical features and beneficial effects of the present invention are as follows:

[0048] 1. The inner straight-chain alkyl A-DA'DA type non-fullerene small molecule synthesized by the present invention can be processed by solution method, can be dissolved in organic solvents such as chloroform and chlorobenzene, and has good film-forming property.

[0049] 2. The inner straight-chain alkyl A-DA'DA type non-fullerene small molecules synthesized by the present invention have good light absorption and suitable electronic energy levels, and are suitable for use as electron acceptor materials in organic solar cells, and exhibit high photoelectric conversion efficiency in organic solar cells.

[0050] 3. The present invention discloses an A-DA'DA type non-fullerene small molecule receptor based on an inner straight-chain alkyl group, and by changing the electron-withdrawing end group, a series of new A-DA'DA type non-fullerene small molecule receptors with inner straight-chain alkyl groups with good solubility and thermal stability are designed and synthesized. By changing the structure of the inner straight-chain alkyl group and the end group of different lengths in the molecular structure, and combining a specific outer alkyl chain, the compactness of the stacking between the small molecule receptors is adjusted, the intermolecular aggregation structure is optimized, and the luminescent performance of the material is optimized. In addition, it is also beneficial to adjust the energy level of the material, improve the photoluminescence quantum yield of the molecule, and thus reduce the non-radiative energy loss of the material. Due to its larger conjugated structure, this type of molecule has a strong intramolecular charge transfer effect and an intermolecular stacking effect. The material of the present invention has a strong light absorption ability, a high electron mobility and a suitable electron energy level, and is suitable for use as an electron acceptor material in the preparation of organic solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is the UV-visible absorption spectrum of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 1;

[0052] Figure 2 This is the UV-visible absorption spectrum of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 2;

[0053] Figure 3 This is the UV-visible absorption spectrum of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 3;

[0054] Figure 4 This is the UV-visible absorption spectrum of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 4;

[0055] Figure 5 The cyclic voltammetry curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 1;

[0056] Figure 6 The cyclic voltammetry curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 2;

[0057] Figure 7 The cyclic voltammetry curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 3;

[0058] Figure 8The cyclic voltammetry curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 4;

[0059] Fig. 9 The JV curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 1 when applied to an organic solar cell;

[0060] Fig.10 The JV curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 2 when applied to an organic solar cell;

[0061] Fig.11 The JV curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Example 3 when applied to an organic solar cell;

[0062] Fig.12 This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner linear alkyl prepared in Example 4 when applied to organic solar cells.

[0063] Fig.13 This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor material based on inner straight-chain alkyl prepared in Comparative Example 1 when applied to organic solar cells.

[0064] Fig.14 This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor material based on the inner side branched alkyl prepared in Comparative Example 2 when applied to an organic solar cell. DETAILED DESCRIPTION

[0065] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and embodiments. However, the present invention is not limited to the embodiments listed, and should also include any other known changes within the scope of the rights claimed by the present invention.

[0066] Example 1

[0067] A synthetic route of an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group is as follows:

[0068]

[0069] The synthesis steps are as follows:

[0070] Step 1) Synthesis of Compound 2

[0071] Under argon protection, compound 1 (500 mg, 0.645 mmol) was added to a 100 mL two-necked round-bottom flask, and then n-hexane bromide (426 mg, 2.58 mmol), K2CO3 (890 mg, 6.45 mmol), anhydrous DMF (30 mL) was added, and the reaction was carried out at 80 ° C for 12 h under Ar2 protection; after the reaction, 250 mL of water was added to the reaction solution for quenching and extraction, and 200 mL of dichloromethane was used to extract and collect the organic phase, and the obtained organic phase was subjected to rotary evaporation to remove the solvent to obtain a crude product, which was further purified by silica gel column chromatography (eluent: dichloromethane: n-hexane = 1:4, v / v) to obtain compound 2 as a red solid, 498 mg, yield: 82%.

[0072] Step 2) Synthesis of compound 3

[0073] Add 5g of POCl3 to a 100mL two-necked flask, and evacuate argon three times. Then put the reaction bottle into an ice-water bath (0℃), add 4mL of DMF dropwise (1 drop / s) under Ar2, and stir at 0℃ for 1h. Then place the two-necked flask at room temperature, dissolve compound 2 (498mg, 0.529mmol) in 35mL of CHCl3, and pour it into the two-necked flask at room temperature. Then put the reaction bottle into a 65℃ oil bath and react at 65℃ for 10h; after the reaction is completed, cool naturally to room temperature, add dichloromethane (200mL) and water (250mL) to the obtained reaction solution for extraction, collect the organic phase, remove the solvent from the obtained organic phase by rotary evaporation, and obtain a crude product, which is further purified by silica gel column chromatography (eluent is dichloromethane: n-hexane = 1:1, v / v) to obtain compound 3, 454mg, yield: 86%.

[0074] Step 3) Synthesis of compound 4

[0075] Compound 3 (454 mg, 0.455 mmol), IC-F end group (310 mg, 1.365 mmol) and CHCl3 (30 mL) were added to a 100 mL two-necked round-bottom flask, and argon was replaced 3 times. Under Ar2, 489 mg of pyridine was added and reacted at 70 ° C for 12 h. After the reaction, the solvent was removed by rotary evaporation, and the product was purified by silica gel column chromatography (eluent was dichloromethane: n-hexane = 1.5: 1, v / v) to obtain compound 4, which is an A-DA'DA type non-fullerene small molecule receptor material based on the inner straight chain alkyl, recorded as BO-C6.

[0076] The NMR data of the product compound 4 are as follows:

[0077] 1H NMR (400MHz, CDCl3): δ (ppm) 8.74 (s, 2H), 8.43 (dd, 2H), 7.58 (t, 2H), 4.68 (m, 4H), 2.92 (d ,4H),2.09(m,6H),1.49(m,8H),1.39(m,12H),1.24(m,24H),0.95(t,6H),0.85(dt,12H);

[0078] 13 C NMR (101MHz, CDCl3): δ (ppm) 185.93, 158.02, 153.44, 152.69, 147.06, 14 5.22,137.16,136.40,134.54,134.24,138.62,132.25,130.41,119.72,1 14.82,114.41,113.41,112.18,111.89,68.99,51.30,39.76,34.65,33.4 7,33.23,31.83,31.64,31.39,29.61,28.90,26.62,22.99,22.65,14.07.

[0079] Example 2

[0080] A synthetic route of an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group is as follows:

[0081]

[0082] The synthesis steps are as follows:

[0083] Step 1) Synthesis of Compound 2

[0084] Under argon protection, compound 1 (500 mg, 0.645 mmol) was added to a 100 mL two-necked round-bottom flask, followed by n-octane bromide (498 mg, 2.58 mmol), K2CO3 (890 mg, 6.45 mmol), and anhydrous DMF (30 mL). The mixture was reacted at 80 ° C for 12 h under Ar2 protection. After the reaction, 250 mL of water was added to the reaction solution for quenching and extraction. 200 mL of dichloromethane was used to extract and collect the organic phase. The obtained organic phase was subjected to rotary evaporation to remove the solvent to obtain a crude product, which was further purified by silica gel column chromatography (eluent: dichloromethane: n-hexane = 1:4, v / v) to obtain compound 2 as a red solid, 541 mg, with a yield of 84%.

[0085] Step 2) Synthesis of compound 3

[0086] Add 5g of POCl3 to a 100mL two-necked flask, and evacuate argon three times. Then put the reaction bottle into an ice-water bath (0℃), add 4mL of DMF dropwise (1 drop / s) under Ar2, and stir at 0℃ for 1h. Then place the two-necked flask at room temperature, dissolve compound 2 (541mg, 0.542mmol) in 35mL of CHCl3, and pour it into the two-necked flask at room temperature. Then put the reaction bottle into a 65℃ oil bath and react at 65℃ for 10h; after the reaction is completed, cool naturally to room temperature, add dichloromethane (200mL) and water (250mL) to the obtained reaction solution for extraction, collect the organic phase, remove the solvent from the obtained organic phase by rotary evaporation, and obtain a crude product, which is further purified by silica gel column chromatography (eluent is dichloromethane: n-hexane = 1:1, v / v) to obtain compound 3, 463mg, yield: 81%.

[0087] Step 3) Synthesis of compound 4

[0088] Compound 3 (463 mg, 0.438 mmol), IC-F end group (298 mg, 1.314 mmol) and CHCl3 (30 mL) were added to a 100 mL two-necked round-bottom flask, and argon was replaced 3 times. Under Ar2, 489 mg of pyridine was added and reacted at 70 ° C for 12 h. After the reaction, the solvent was removed by rotary evaporation, and the product was purified by silica gel column chromatography (eluent was dichloromethane: n-hexane = 1.5: 1, v / v) to obtain compound 4, which is an A-DA'DA type non-fullerene small molecule receptor material based on the inner straight chain alkyl, recorded as BO-C8.

[0089] The NMR data of the product compound 4 are as follows:

[0090] 1 H NMR (400MHz, CDCl3): δ (ppm) 8.76 (s, 2H), 8.45 (dd, 2H), 7.59 (t, 2H), 4.68 (m, 4H), 2.92 ( d,4H),2.10(m,4H),1.96(m,2H),1.49(m,8H),1.39(m,12H),1.24(m,32H),0.85(m,18H);

[0091] 13C NMR (101MHz, CDCl3): δ (ppm) 185.97, 157.91, 153.51, 152.94, 147.09, 145. 19,137.16,134.62,134.29,133.63,132.32,130.48,119.72,114.84,114. 67,114.47,113.43,112.82,112.17,69.00,51.36,39.78,34.67,33.47,33 .22,31.83,31.62,29.61,29.31,28.89,26.65,26.64,22.99,22.66,14.11.

[0092] Example 3

[0093] A synthetic route of an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group is as follows:

[0094]

[0095] The synthesis steps are as follows:

[0096] Step 1) Synthesis of Compound 2

[0097] Under argon protection, compound 1 (500 mg, 0.645 mmol) was added to a 100 mL two-necked round-bottom flask, and then decane bromide (570 mg, 2.58 mmol), K2CO3 (890 mg, 6.45 mmol), anhydrous DMF (30 mL) was added, and the reaction was carried out at 80 ° C for 12 h under Ar2 protection; after the reaction, 250 mL of water was added to the reaction solution for quenching and extraction, and 200 mL of dichloromethane was used to extract and collect the organic phase, and the obtained organic phase was subjected to rotary evaporation to remove the solvent to obtain a crude product, which was further purified by silica gel column chromatography (eluent: dichloromethane: n-hexane = 1:4, v / v) to obtain compound 2 as a red solid, 545 mg, yield: 80%.

[0098] Step 2) Synthesis of compound 3

[0099] Add 5g of POCl3 to a 100mL two-necked flask, and evacuate argon three times. Then put the reaction bottle into an ice-water bath (0℃), add 4mL of DMF dropwise (1 drop / s) under Ar2, and stir at 0℃ for 1h. Then place the two-necked flask at room temperature, dissolve compound 2 (545mg, 0.516mmol) in 35mL of CHCl3, and pour it into the two-necked flask at room temperature. Then put the reaction bottle into a 65℃ oil bath and react at 65℃ for 10h; after the reaction is completed, cool naturally to room temperature, add dichloromethane (200mL) and water (250mL) to the obtained reaction solution for extraction, collect the organic phase, remove the solvent from the obtained organic phase by rotary evaporation, and obtain a crude product, which is further purified by silica gel column chromatography (eluent is dichloromethane: n-hexane = 1:1, v / v) to obtain compound 3, 476mg, yield: 83%.

[0100] Step 3) Synthesis of compound 4

[0101] Compound 3 (476 mg, 0.428 mmol), IC-F end group (291 mg, 1.285 mmol) and CHCl3 (30 mL) were added to a 100 mL two-necked round-bottom flask, and argon was replaced 3 times. Under Ar2, 489 mg of pyridine was added and reacted at 70 ° C for 12 h. After the reaction, the solvent was removed by rotary evaporation, and the product was purified by silica gel column chromatography (eluent was dichloromethane: n-hexane = 1.5: 1, v / v) to obtain compound 4, which is an A-DA'DA type non-fullerene small molecule receptor material based on the inner straight chain alkyl, recorded as BO-C10.

[0102] The NMR data of the product compound 4 are as follows:

[0103] 1 H NMR (400MHz, CDCl3): δ (ppm) 8.71 (s, 2H), 8.42 (dd, 2H), 7.56 (t, 2H), 4.66 (m, 4H), 2.89 ( d,4H),2.12(m,4H),1.94(m,2H),1.52(m,8H),1.36(m,12H),1.24(m,40H),0.85(m,18H);

[0104] 13C NMR (101MHz, CDCl3): δ (ppm) 185.82, 157.75, 155.44, 153.40, 152.99, 152.86, 147.02, 145.21,137.11,136.37,134.48,134.16,133.60,132.20,130.41,119.66,114.80,114 .63,114.44,113.36,112.09,111.19,69.07,51.39,39.74,34.60,33.46,33.21,31.97,31.84,31.72,29.76,29.66,29.61,29.44,28.89,27.02,26.65,22.99,22.69,14.11.

[0105] Example 4

[0106] A synthetic route of an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group is as follows:

[0107]

[0108] The synthesis steps are as follows:

[0109] Step 1) Synthesis of Compound 2

[0110] Under argon protection, compound 1 (500 mg, 0.645 mmol) was added to a 100 mL two-necked round-bottom flask, and then n-dodecane bromide (643 mg, 2.58 mmol), K2CO3 (890 mg, 6.45 mmol, anhydrous DMF (30 mL) was added, and the reaction was carried out at 80 ° C for 12 h under Ar2 protection; after the reaction, 250 mL of water was added to the reaction solution for quenching and extraction, and 200 mL of dichloromethane was used to extract and collect the organic phase, and the obtained organic phase was subjected to rotary evaporation to remove the solvent to obtain a crude product, which was further purified by silica gel column chromatography (eluent: dichloromethane: n-hexane = 1:4, v / v) to obtain compound 2 as a red solid, 580 mg, yield: 81%.

[0111] Step 2) Synthesis of compound 3

[0112] Add 5g of POCl3 to a 100mL two-necked flask, and evacuate argon three times. Then put the reaction bottle into an ice-water bath (0℃), add 4mL of DMF dropwise (1 drop / s) under Ar2, and stir at 0℃ for 1h. Then place the two-necked flask at room temperature, dissolve compound 2 (580mg, 0.522mmol) in 35mL of CHCl3, and pour it into the two-necked flask at room temperature. Then put the reaction bottle into a 65℃ oil bath and react at 65℃ for 10h; after the reaction is completed, cool naturally to room temperature, add dichloromethane (200mL) and water (250mL) to the obtained reaction solution for extraction, collect the organic phase, remove the solvent from the obtained organic phase by rotary evaporation, and obtain a crude product, which is further purified by silica gel column chromatography (eluent is dichloromethane: n-hexane = 1:1, v / v) to obtain compound 3, 481mg, yield: 83%.

[0113] Step 3) Synthesis of compound 4

[0114] Compound 3 (481 mg, 0.412 mmol), IC-F end group (280 mg, 1.236 mmol) and CHCl3 (30 mL) were added to a 100 mL two-necked round-bottom flask, and argon was replaced 3 times. Under Ar2, 489 mg of pyridine was added and reacted at 70 ° C for 12 h. After the reaction, the solvent was removed by rotary evaporation, and the product was purified by silica gel column chromatography (eluent was dichloromethane: n-hexane = 1.5: 1, v / v) to obtain compound 4, which is an A-DA'DA type non-fullerene small molecule receptor material based on the inner straight chain alkyl, recorded as BO-C12.

[0115] The NMR data of the product are as follows:

[0116] 1 H NMR (400MHz, CDCl3): δ (ppm) 8.75 (s, 2H), 8.45 (dd, 2H), 7.59 (t, 2H), 4.67 (m, 4H), 2.91 ( d,4H),2.10(m,4H),1.94(m,2H),1.48(m,8H),1.36(m,12H),1.22(m,48H),0.84(m,18H);

[0117] 13C NMR (101MHz, CDCl3): δ (ppm) 185.84, 157.80, 155.59, 155.47, 153.38, 153.00, 152.89, 152.86,147.04,145.17,137.13,136.38,134.53,134.26,133.61,132.28,130.43,119 .74,114.82,114.45,113.39,112.13,111.94,69.07,51.40,39.75,34.61,33.47,33.22,31.92,31.67,29.81,29.73,29.62,29.42,28.89,26.98,26.65,22.99,22.67,14.12.

[0118] Comparative Example 1

[0119] A synthetic route of an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group is as follows:

[0120]

[0121] The synthesis steps are as follows:

[0122] Step 1) Synthesis of Compound 2

[0123] Under argon protection, compound 1 (500 mg, 0.669 mmol) was added to a 100 mL two-necked round-bottom flask, and then n-bromodecane (592 mg, 2.68 mmol), K2CO3 (923 mg, 6.69 mmol, anhydrous DMF (30 mL) was added, and the reaction was carried out at 80 ° C for 12 h under Ar2 protection; after the reaction, 250 mL of water was added to the reaction solution for quenching and extraction, and 200 mL of dichloromethane was used to extract and collect the organic phase, and the obtained organic phase was subjected to rotary evaporation to remove the solvent to obtain a crude product, which was further purified by silica gel column chromatography (eluent: dichloromethane: n-hexane = 1:4, v / v) to obtain a red solid compound 2, 571 mg, yield: 83%.

[0124] Step 2) Synthesis of compound 3

[0125] Add 5g of POCl3 to a 100mL two-necked flask, and evacuate argon three times. Then put the reaction bottle into an ice-water bath (0℃), add 4mL of DMF dropwise (1 drop / s) under Ar2, and stir at 0℃ for 1h. Then place the two-necked flask at room temperature, dissolve compound 2 (571mg, 0.555mmol) in 35mL of CHCl3, and pour it into the two-necked flask at room temperature. Then put the reaction bottle into a 65℃ oil bath and react at 65℃ for 10h; after the reaction is completed, cool naturally to room temperature, add dichloromethane (200mL) and water (250mL) to the obtained reaction solution for extraction, collect the organic phase, remove the solvent from the obtained organic phase by rotary evaporation, and obtain a crude product, which is further purified by silica gel column chromatography (eluent is dichloromethane: n-hexane = 1:1, v / v) to obtain compound 3, 493mg, yield: 82%.

[0126] Step 3) Synthesis of compound 4

[0127] Compound 3 (493 mg, 0.455 mmol), IC-F end group (309 mg, 1.365 mmol) and CHCl3 (30 mL) were added to a 100 mL two-necked round-bottom flask, and argon was replaced 3 times. Under Ar2, 489 mg of pyridine was added and reacted at 70 ° C for 12 h. After the reaction, the solvent was removed by rotary evaporation, and the product was purified by silica gel column chromatography (eluent was dichloromethane: n-hexane = 1.5: 1, v / v) to obtain compound 4, which is an A-DA'DA type non-fullerene small molecule receptor material based on the inner straight chain alkyl, which is Y6-C10.

[0128] The NMR data of the product are as follows:

[0129] 1 H NMR (400MHz, CDCl3): δ (ppm) 8.77 (s, 2H), 8.46 (t, 2H), 7.60 (t, 2H), 4.68 (m, 4H), 3.00 (m, 4H), 2 .09-1.99(m,4H),1.84-1.72(m,4H),1.50-1.39(m,8H),1.38-1.12(m,52H),0.92-0.78(m,12H);

[0130] 13C NMR (101MHz, CDCl3): δ (ppm) 185.61, 157.37, 155.59, 155.47, 153.31, 152.65, 152.38, 1 47.00,145.28,137.25,136.41,134.66,134.54,133.71,132.54,130.32,119.47,114.23 ,114.15,113.31,112.10,111.88,69.70,66.73,36.92,36.34,31.94,31.92,29.79,29.71,29.66,29.64,29.58,29.52,29.37,29.29,28.41,22.71,22.67,21.01,14.14,14.07.

[0131] Comparative Example 2

[0132] A synthetic route of an A-DA'DA type non-fullerene small molecule receptor material based on an inner side branched alkyl group is as follows:

[0133]

[0134] The synthesis steps are as follows:

[0135] Step 1) Synthesis of Compound 2

[0136] Under argon protection, compound 1 (500 mg, 0.645 mmol) was added to a 100 mL two-necked round-bottom flask, and then 3-(bromomethyl)heptane (498 mg, 2.58 mmol), K2CO3 (890 mg, 6.45 mmol, anhydrous DMF (30 mL) was added, and the reaction was carried out at 80 ° C for 12 h under Ar2 protection; after the reaction, 250 mL of water was added to the reaction solution for quenching and extraction, and 200 mL of dichloromethane was used to extract and collect the organic phase, and the obtained organic phase was subjected to rotary evaporation to remove the solvent to obtain a crude product, which was further purified by silica gel column chromatography (eluent: dichloromethane: n-hexane = 1:4, v / v) to obtain a red solid compound 2, 503 mg, yield: 78%.

[0137] Step 2) Synthesis of compound 3

[0138] Add 5g of POCl3 to a 100mL two-necked flask, and evacuate argon three times. Then put the reaction bottle into an ice-water bath (0℃), add 4mL of DMF dropwise (1 drop / s) under Ar2, and stir at 0℃ for 1h. Then place the two-necked flask at room temperature, dissolve compound 2 (503mg, 0.503mmol) in 35mL of CHCl3, and pour it into the two-necked flask at room temperature. Then put the reaction bottle into a 65℃ oil bath and react at 65℃ for 10h; after the reaction is completed, cool naturally to room temperature, add dichloromethane (200mL) and water (250mL) to the obtained reaction solution for extraction, collect the organic phase, remove the solvent from the obtained organic phase by rotary evaporation, and obtain a crude product, which is further purified by silica gel column chromatography (eluent is dichloromethane: n-hexane = 1:1, v / v) to obtain compound 3, 425mg, yield: 80%.

[0139] Step 3) Synthesis of compound 4

[0140] Compound 3 (425 mg, 0.402 mmol), IC-F end group (277 mg, 1.206 mmol) and CHCl3 (30 mL) were added to a 100 mL two-necked round-bottom flask, and argon was replaced 3 times. Under Ar2, 489 mg of pyridine was added and reacted at 70 ° C for 12 h. After the reaction, the solvent was removed by rotary evaporation, and the product was purified by silica gel column chromatography (eluent was dichloromethane: n-hexane = 1.5:1, v / v) to obtain compound 4, which is an A-DA'DA type non-fullerene small molecule receptor material based on the inner side branched alkyl, which is L8-BO.

[0141] The NMR data of the product are as follows:

[0142] 1 H NMR (400MHz, CDCl3): δ (ppm) 9.15 (s, 2H), 8.59-8.55 (m, 2H), 7.73-7.69 (t, 2H), 4.79-4.77 (d, 4H), 3.19-3.18 (d, 4 H),2.09-2.08(m,4H),1.47-1.23(m,36H),1.06-1.01(m,12H),0.88-0.82(m,12H),0.77-0.76(t,6H),0.67(t,6H);

[0143] 13C NMR (101MHz, CDCl3): δ (ppm) 185.02, 157.95, 155.14, 152.51, 146.54, 144.29, 136.62, 135.61, 134.71, 134.60, 133.52, 133.01, 132 .85,129.65,119.02,114.10,113.73,113.54,112.56,111.55,111.30,67.69,54.66,39.38,39.03,33.73,32.56,32.31,30.80,104 28.60,27.82,26.62,25.56,22.25,21.97,21.62,13.05,13.03,12.71,9.24.

[0144] Test Example 1

[0145] The following tests were performed on the A-DA'DA type non-fullerene small molecule receptor materials based on inner straight chain alkyl prepared in Examples 1-4:

[0146] 1. UV-visible absorption spectrum test:

[0147] The test was carried out on an Agilent Technologies Cary series UV-Vis-NIR spectrophotometer. Chloroform was used as the solvent for the absorption spectrum of the solution, and the small molecule receptor material was prepared into a 10 μg / mL solution. The absorption sample of the film was prepared by spin coating a 15 mg / mL chloroform solution of the small molecule receptor material on a quartz wafer at 3000 rpm for 30 s.

[0148] The UV-visible absorption spectra of the A-DA'DA type non-fullerene small molecule acceptor materials based on inner straight-chain alkyl groups prepared in Examples 1-4 are shown in FIG. Figure 1-4 As shown by Figure 1-4 It can be seen that the prepared A-DA'DA type non-fullerene small molecule acceptor material based on inner straight chain alkyl has strong absorption in the range of 550-850nm, and the film absorption has a significant red shift compared to the solution absorption, indicating that there is a strong interaction and aggregation between molecules. The maximum absorption peak positions of BO-C6, BO-C8, BO-C10 and BO-C12 in the UV-visible absorption spectrum are 781nm, 783nm, 786nm and 774nm respectively. The BO-C10 acceptor material shows a more red-shifted absorption, which increases the range of light absorption, which is beneficial to improve the short-circuit current of the material, thereby improving the photovoltaic performance of the organic solar cell device.

[0149] 2. The energy level of the material is tested by electrochemical cyclic voltammetry:

[0150] On a Zahner-Ennium IM6 electrochemical workstation, a glassy carbon disk was used as the working electrode, a Pt wire was used as the counter electrode, and an Ag / Ag + The electrode was used as a reference electrode and tested in 0.1 mol / L tetrabutylammonium hexafluorophosphate (Bu4NPF6) acetonitrile solution at a scan rate of 50 mV / s.

[0151] The cyclic voltammetry curves of the A-DA'DA type non-fullerene small molecule receptor materials based on inner straight-chain alkyl prepared in Examples 1-4 are shown in FIG. Figure 5-8 As shown, by the formula HOMO = -(E ox +4.73)(eV) and LUMO=-(E re +4.73)(eV) can be used to calculate the HOMO and LUMO energy levels of the acceptor material. Figure 5 As shown, the initial oxidation potential of the small molecule receptor material prepared in Example 1 is 1.07Vvs Ag / Ag + , initial reduction potential Yes -0.87V vs Ag / Ag + , the HOMO and LUMO energy levels of BO-C6 are calculated to be -5.80eV and -3.86eV respectively; Figure 6 As shown, the initial oxidation potential of the small molecule receptor material prepared in Example 2 is is 1.07V vs Ag / Ag + , initial reduction potential Yes -0.86V vs Ag / Ag + , the HOMO and LUMO energy levels of BO-C8 are calculated to be -5.80eV and -3.87eV respectively; Figure 7 As shown, the initial oxidation potential of the small molecule receptor material prepared in Example 3 is is 1.06V vs Ag / Ag + , initial reduction potential Yes -0.86Vvs Ag / Ag + , the HOMO and LUMO energy levels of BO-C10 are calculated to be -5.79eV and -3.87eV respectively; Figure 8 As shown, the initial oxidation potential of the small molecule receptor material prepared in Example 4 is is 1.05V vs Ag / Ag + , initial reduction potential Yes -0.85V vs Ag / Ag + The HOMO and LUMO energy levels of BO-C12 were calculated to be -5.78 eV and -3.88 eV, respectively, which can match the efficient polymer donor.

[0152] Test Example 2

[0153] The A-DA'DA type non-fullerene small molecule acceptor materials prepared in Examples 1-4 and Comparative Examples 1-2 were used to prepare solar photovoltaic devices, and performance tests were performed. The preparation method of the solar photovoltaic device is as follows:

[0154] The commercially purchased indium tin oxide (ITO) glass was first cleaned with detergent, then ultrasonically cleaned with water, deionized water, acetone, and isopropanol in sequence, and dried. After that, the anode buffer layer PEDOT:PSS (thickness 25nm) was spin-coated on the ITO. A chloroform mixed solution of the polymer donor D18 and the A-DA'DA type non-fullerene small molecule acceptor material (weight ratio of 1:1.3) (the concentration of the A-DA'DA type non-fullerene small molecule acceptor in the mixed solution is 10.35mg / mL) was spin-coated on the PEDOT:PSS layer to form the active layer of the device (thickness 100nm), and then CS2 was used as the solvent for solvent annealing for 30s. Then, PFN-Br as the cathode buffer layer (thickness 15nm) was spin-coated on the active layer, and finally a 100nm thick metallic silver was evaporated on the PFN-Br as the anode of the photovoltaic device. The effective area of ​​each cell in the active layer of the photovoltaic device is 0.052cm -2 .

[0155] A SS-F5-3A (Enli Technology CO., Ltd.) xenon lamp with an AM1.5 filter was used as a simulated sunlight source at 100 mW cm -2 The photovoltaic performance of the device was tested under light intensity, and the light intensity was calibrated by a standard single-crystalline silicon solar cell; the JV curve was measured using Keithley 2450.

[0156] The structure of the polymer donor D18 used in the present invention is as follows:

[0157]

[0158] Fig. 9 This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor BO-C6 based on inner straight chain alkyl prepared in Example 1 when applied to organic solar cells. Fig. 9 As shown, the short-circuit current J of the device is measured sc 26.7 mA cm -1 , open circuit voltage V oc The V is 0.902 V, the fill factor FF is 80.7%, and the energy conversion efficiency PCE is 19.5%.

[0159] Fig.10This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor BO-C8 based on inner straight chain alkyl prepared in Example 2 when applied to organic solar cells. Fig.10 As shown, the short-circuit current J of the device is measured sc 26.9mAcm -1 , open circuit voltage V oc It is 0.911V, the fill factor FF is 80.6%, and the energy conversion efficiency PCE is 19.8%.

[0160] Fig.11 This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor BO-C10 based on inner straight chain alkyl prepared in Example 3 when applied to organic solar cells. Fig.11 As shown, the short-circuit current J of the device is measured sc 27.2mAcm -1 , open circuit voltage V oc It is 0.926V, the fill factor FF is 80.5%, and the energy conversion efficiency PCE is 20.3%.

[0161] Fig.12 This is the JV curve of the A-DA'DA type non-fullerene small molecule acceptor BO-C12 based on inner straight chain alkyl prepared in Example 4 when applied to organic solar cells. Fig.12 As shown, the short-circuit current J of the device is measured sc 26.1mAcm -1 , open circuit voltage V oc It is 0.931V, the fill factor FF is 78.9%, and the energy conversion efficiency PCE is 19.2%.

[0162] Fig.13 The JV curve of the A-DA'DA type non-fullerene small molecule receptor Y6-C10 based on the inner straight chain alkyl prepared in Comparative Example 1 when applied to organic solar cells. Fig.13 As shown, the short-circuit current J of the device is measured sc 26.8mAcm -1 , open circuit voltage V oc It is 0.894V, the fill factor FF is 76.5%, and the energy conversion efficiency PCE is 18.4%.

[0163] Fig.14 The JV curve of the A-DA'DA type non-fullerene small molecule receptor L8-BO based on the inner side branched alkyl prepared in Comparative Example 2 when applied to organic solar cells. Fig.14 As shown, the short-circuit current J of the device is measured sc 26.9mAcm -1 , open circuit voltage Voc It is 0.911V, the fill factor FF is 78.2%, and the energy conversion efficiency PCE is 19.2%.

[0164] The four acceptor materials BO-C6, BO-C8, BO-C10 and BO-C12 showed photoelectric conversion efficiencies of 19.5%, 19.8%, 20.3% and 19.2%, respectively. Among them, BO-C10 showed the best results due to its highest fill factor FF, short-circuit current, and relatively high open circuit voltage. In addition, compared with the comparative examples Y6-C10 and L8-BO, BO-C10 has higher open circuit voltage, short-circuit current and fill factor FF, and thus has better photovoltaic performance.

[0165] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An A-DA'DA type non-fullerene small molecule receptor material based on inner straight chain alkyl, characterized in that: It has the structure shown in the following formula I: Wherein, in Formula I, R is C6~C 12 A straight chain alkyl group; X is S, O or Se; A is an electron-withdrawing group containing active α hydrogen.

2. The A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 1, characterized in that: The A is selected from one of the following structures: in, R1 is C1~C 30 Alkyl, R2 is C1~C 30 of alkyl.

3. The A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 1, characterized in that: The A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl has a structure as shown in the following formula I-1:

4. The method for preparing the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl as claimed in claim 1, comprising the following steps: (1) Compound 1 and compound R-Br are reacted in N,N-dimethylformamide in the presence of potassium carbonate to obtain compound 2; In compound 1, the substituent X is the same as X in formula Ⅰ; in compound R-Br, the substituent R is the same as R in formula Ⅰ; (2) stirring phosphorus oxychloride and N,N-dimethylformamide at 0-5° C., then adding a chloroform solution of compound 2 to react to obtain compound 3; (3) In chloroform, under the action of pyridine, compound 3 and a compound containing an A unit are reacted to obtain an A-DA'DA type non-fullerene small molecule receptor material based on an inner straight-chain alkyl group; The compound containing A unit is selected from one of the following compounds:

5. The method for preparing the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 4, characterized in that: In step (1), the volume ratio of N,N-dimethylformamide to the mass ratio of compound 1 is 30-100 mL:1 g; the molar ratio of potassium carbonate to compound 1 is 5-20:1; and the molar ratio of compound R-Br to compound 1 is 3-5:

1.

6. The method for preparing the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 4, characterized in that: The reaction temperature in step (1) is 70-90° C., and the reaction time is 10-15 h. The reaction is carried out under a protective gas, and the protective gas is argon or nitrogen. In step (1), the post-treatment step of the reaction solution obtained by the reaction is as follows: adding water to the obtained reaction solution, wherein the ratio of the added volume of water to the molar number of compound 1 is 300-500 mL:1 mmol; then extracting with dichloromethane, removing the solvent from the obtained organic phase to obtain a crude product, and purifying the obtained crude product by silica gel column chromatography to obtain compound 2, wherein the eluent is dichloromethane:n-hexane = 1:4, v / v.

7. The method for preparing the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 4, characterized in that: The ratio of the volume of N,N-dimethylformamide to the mass of phosphorus oxychloride in step (2) is 0.5-1mL:1g; the stirring reaction time of phosphorus oxychloride and N,N-dimethylformamide is 1-2h; The concentration of the chloroform solution of compound 2 in step (2) is 10-20 mg / mL; the molar ratio of phosphorus oxychloride to compound 2 is 55-70:1; the chloroform solution of compound 2 is added at room temperature, the reaction temperature after adding compound 2 is 60-70° C., and the reaction time is 10-12 h; the reaction is carried out under protective gas, and the protective gas is argon or nitrogen; The post-treatment steps of the reaction solution obtained in step (2) are as follows: dichloromethane and water are added to the obtained reaction solution for extraction, the solvent is removed from the obtained organic phase, and the obtained crude product is purified by silica gel column chromatography to obtain compound 3, and the eluent is dichloromethane:n-hexane=1:1, v / v.

8. The method for preparing the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 4, characterized in that: In step (3), the volume ratio of chloroform to the mass ratio of compound 3 is 50-100 mL:1 g; the molar ratio of pyridine to compound 3 is 10-20:1; and the molar ratio of the compound containing A unit to compound 3 is 2-4:

1.

9. The method for preparing the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl according to claim 4, characterized in that: The reaction temperature in step (3) is 65-75° C., and the reaction time is 8-15 h; the reaction is carried out under a protective gas, and the protective gas is argon or nitrogen; In step (3), the post-treatment step of the reaction solution obtained by the reaction is as follows: the solvent is removed from the reaction solution, and the crude product is purified by silica gel column chromatography, with the eluent being dichloromethane:n-hexane = 1.5:1, v / v.

10. The use of the A-DA'DA type non-fullerene small molecule receptor material based on inner straight-chain alkyl as claimed in claim 1, characterized in that: As light-harvesting active layer electron acceptor materials used in the preparation of organic solar cells.

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