A class of receptor materials with locking side chains, their preparation methods and applications

Abstract

This invention relates to the field of organic optoelectronic materials technology, and particularly to a class of acceptor materials with locked side chains, their preparation methods, and applications. Using dithiophene[2'',3'':4',5']thiophene[2',3':4,5]pyrrolo[3,2-E:2',3'-G][2,1,3]benzothiadiazole,12,13-dihydro as the basic building block, this invention synthesizes a class of acceptor materials with locked side chains through derivatization. This invention employs olefin metathesis to covalently lock the side chains, relying on a rigid macrocycle to fix the molecular side chain configuration, effectively improving electron mobility and reducing charge recombination; simultaneously, the terminal halogen atom and cyano group synergistically regulate the energy level, broadening the light absorption range and enhancing exciton dissociation capability, significantly improving the photoelectric conversion efficiency, long-term illumination, and thermal stability of organic solar cells.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials technology, and in particular to a class of acceptor materials with locking side chains, their preparation methods and applications. Background Technology

[0002] Organic solar cells, with their advantages of being lightweight, flexible, solution-printable, and semi-transparent, have significant industrial value in fields such as flexible electronics, photovoltaic buildings, and indoor low-light power generation. Non-fullerene small molecule acceptors are the core materials that determine the photoelectric conversion efficiency, charge transport, and stability of devices. Among them, A-DA'DA type fused ring acceptors have become the mainstream system due to their wide absorption range, tunable energy levels, and high mobility. Thiophene-pyrrole acceptors, represented by Y6 and L8-BO, have achieved device efficiencies of over 18%, propelling organic photovoltaics into the industrialization verification stage.

[0003] L8-BO optimizes molecular packing and crystallinity by introducing branched side chains, slightly improving the device fill factor, but it does not fundamentally solve the core problem of free side chains. Its side chains rely solely on steric hindrance for weak confinement, lacking a covalently locked structure, and still exhibit conformational distortion and molecular slip under external stimuli. Furthermore, the disordered extension of the branches easily leads to uneven film crystallization, making it difficult to reduce non-radiative recombination losses, and also weakens molecular planarity, limiting light absorption and exciton dissociation capabilities, thus failing to meet the demands of commercially viable, efficient, and highly stable mass production.

[0004] Currently, industry modifications to this type of receptor primarily focus on regulating free side chains through alkyl chain length, branching sites, and terminal halogenation. These methods rely solely on weak intermolecular forces to optimize the aggregation state, failing to fix the side chain configuration at the intrinsic molecular level. Existing technologies lack molecular design schemes for covalent ring closure via olefin metathesis and macrocyclic locking of side chains, as well as complete synthetic processes and photovoltaic application systems adapted to this fused-ring skeleton.

[0005] In summary, existing Y6 and L8-BO type fused ring acceptors are constrained by flexible free side chains and generally suffer from shortcomings such as conformational instability, low molecular packing order, severe charge recombination, poor device stability, and complex processing technology. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned shortcomings of existing technologies by proposing a class of acceptor materials with locked side chains, their preparation methods, and applications. By locking the spatial configuration of the side chains with covalent macrocycles, molecular packing and photoelectric properties are precisely optimized, enabling the fabrication of organic photovoltaic devices that combine high efficiency, high stability, and easy processing, thus overcoming the deficiencies of existing technologies.

[0007] The first objective of this invention is to provide a receptor material with locking side chains, the structural formula of which is shown below: .

[0008] A second objective of this invention is to provide a method for preparing a receptor material with locking side chains as described above, comprising the following steps: Step 1: Using compound 1 as a starting material, react with 8-bromo-1-octene to obtain compound 2: ; The structural formula of compound 1 is as follows: ; Step 2: Using compound 2 as a starting material, the reaction proceeds under the action of Grubbs second-generation catalyst to obtain compound 3: ; Step 3: Using compound 3 as a starting material, react with phosphorus oxychloride and DMF to obtain compound 4: ; Step 4: Using compound 4 as a starting material, it is reacted with 5,6-difluoro-3-(dicyanomethylene)indoketone via a Knoevenagel condensation reaction to obtain compound A: .

[0009] Further, step 1 is specifically performed as follows: under a nitrogen protective atmosphere, 8-bromo-1-octene, potassium carbonate, potassium iodide and DMF are added to a reaction flask containing compound 1, heated to 110°C and reacted for 12 h, and compound 2 is obtained after purification; The molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate, and potassium iodide is 1:(2-6):(3-7):(1-2). Further, step 2 is specifically performed as follows: under a nitrogen protective atmosphere, Grubbs second-generation catalyst and DCM are added to the reaction flask containing compound 2, heated to 70°C and reacted for 12 h, and compound 3 is obtained after purification; The molar ratio of compound 2 to the Grubbs second-generation catalyst is 1:(0.1-0.3). Further, step 3 is specifically performed as follows: under a nitrogen protective atmosphere and at 0°C, DMF is added dropwise to a reaction flask containing phosphorus oxychloride and the reaction is maintained at 0°C for 40 min. Then, the reaction solution is dropped into a reaction flask containing compound 3 and 1,2-dichloroethane solution, heated to 80°C and reacted for 12 h, and compound 4 is obtained after purification. The molar ratio of compound 3, phosphorus oxychloride, and DMF is 1:(12-18):(50-60). Further, step 4 is specifically performed as follows: under a nitrogen protective atmosphere, 5,6-difluoro-3-(dicyanomethylene)indone, pyridine, and chloroform are added to a reaction flask containing compound 4, and the mixture is heated to 70°C and reacted for 12 h to obtain compound A after purification.

[0010] The molar ratio of compound 4 to 5,6-difluoro-3-(dicyanomethylene)indone is 1:(6-10).

[0011] Further, in step 1, the molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate and potassium iodide is 1:4:5:1; In step 2, the molar ratio of compound 2 to the Grubbs second-generation catalyst is 1:0.2; In step 3, the molar ratio of compound 3, phosphorus oxychloride, and DMF is 1:15:55; In step 4, the molar ratio of compound 4 and 5,6-difluoro-3-(dicyanomethylene)indone is 1:10.

[0012] A third objective of this invention is to provide another method for preparing a receptor material with locking side chains as described above, comprising the following steps: Step 1: Using compound 1 as a starting material, react with 8-bromo-1-octene to obtain compound 2: ; The structural formula of compound 1 is as follows: ; Step 2: Using compound 2 as a starting material, compound 5 is obtained by reacting it with phosphorus oxychloride and DMF. ; Step 3: Using compound 5 as a starting material, compound 6 was obtained by Knoevenagel condensation reaction with 5,6-difluoro-3-(dicyanomethylene)indoketone. ; Step 4: Using compound 6 as a starting material, react with Grubbs II catalyst to obtain compound A: .

[0013] Further, step 1 is specifically performed as follows: under a nitrogen protective atmosphere, 8-bromo-1-octene, potassium carbonate, potassium iodide and DMF are added to a reaction flask containing compound 1, heated to 110°C and reacted for 12 h, and compound 2 is obtained after purification; The molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate and potassium iodide is 1:(2-6):(3-7):(1-2).

[0014] Further, step 2 is specifically performed as follows: under a nitrogen protective atmosphere and at 0°C, DMF is added dropwise to a reaction flask containing phosphorus oxychloride and the reaction is maintained at 0°C for 40 min. Then, the reaction solution is dropped into a reaction flask containing compound 2 and 1,2-dichloroethane solution, heated to 80°C and reacted for 12 h, and compound 5 is obtained after purification. The molar ratio of compound 2, phosphorus oxychloride and DMF is 1:(12-18):(50-60).

[0015] Further, step 3 is specifically performed as follows: under a nitrogen protective atmosphere, 5,6-difluoro-3-(dicyanomethylene)indone, pyridine and chloroform are added to a reaction flask containing compound 5, and the mixture is heated to 70°C and reacted for 12 h to obtain compound 6 after purification; The molar ratio of compound 5 and 5,6-difluoro-3-(dicyanomethylene)indone is 1:(6-10).

[0016] Further, step 4 includes: under a nitrogen protective atmosphere, adding Grubbs second-generation catalyst and DCM to a reaction flask containing compound 6, heating to 70°C and reacting for 12 h, and purifying to obtain compound A.

[0017] The molar ratio of compound 6 to the Grubbs second-generation catalyst is 1:(0.1-0.3).

[0018] Further, in step 1, the molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate and potassium iodide is 1:4:5:1; In step 2, the molar ratio of compound 2, phosphorus oxychloride, and DMF is 1:15:55; In step 3, the molar ratio of compound 5 and 5,6-difluoro-3-(dicyanomethylene)indone is 1:10; The molar ratio of compound 6 and Grubbs second-generation catalyst in step 4 is 1:0.2.

[0019] A fourth objective of this invention is to provide an organic solar cell in which the acceptor material is the acceptor material with locked side chains as described above.

[0020] Furthermore, the donor material is D18, and its structural formula is as follows:

[0021] The mass ratio of donor material to acceptor material is 1:(1.0-1.5), preferably 1:1.2; the thickness of the active layer is 80-150 nm, preferably 100 nm.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention innovatively adopts the olefin metathesis reaction to covalently lock the side chain, and relies on the rigid macrocycle to fix the molecular side chain configuration, which solves the problems of easy deformation of the free alkyl side chain of the traditional acceptor and disordered molecular stacking, effectively improving electron mobility and reducing charge recombination; moreover, the branched side chain can regulate the molecular stacking mode, forming a more ordered π-π stacking and intertwined assembly structure, which greatly improves electron mobility and reduces charge recombination; at the same time, the terminal halogen atom and cyano group can enhance the electron-withdrawing ability of the molecule, synergistically regulate the energy level, broaden the light absorption range, improve the exciton dissociation ability, achieve a narrow band gap and low LUMO energy level, and improve the light absorption and exciton dissociation efficiency. The photoelectric conversion efficiency and long-term light and thermal stability of the organic solar cell are significantly improved.

[0023] (2) The acceptor material has branched alkyl chains, which have excellent solubility in photovoltaic solvents such as chloroform and chlorobenzene. The film is uniform and defect-free, and is suitable for industrial solution processing technology such as spin coating and blade coating. This enables organic solar cell devices based on this material to achieve high photoelectric conversion efficiency, and has excellent stability and commercial application potential.

[0024] (3) This invention provides two synthetic routes, the reaction order can be adjusted as needed, the reaction conditions are mild, the products are easy to purify, and the molecular side chains and halogen substituents can be flexibly adjusted. When combined with D18 donor, a highly efficient active layer with a wide process window can be obtained, and the potential for industrial application is outstanding. Attached Figure Description

[0025] Figure 1 Compound A prepared in Example 1 1 H NMR spectrum; Figure 2 Compound A prepared in Example 1 13 C NMR spectrum; Figure 3 The HRMS spectrum of compound A prepared in Example 1; Figure 4 The current density-voltage (JV) test diagram and the external quantum efficiency (EQE) test diagram of the binary organic solar energy device prepared for this invention are shown. Figure 5 The images show the UV-Vis spectra of compound A in solution and thin film. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0027] Unless otherwise specified, the "water" used in the following examples refers to deionized water.

[0028] In the following tests of this invention, proton and carbon NMR spectra were performed on an AVANCE NEO 400MHz NMR spectrometer from Bruker GmbH, Germany, using deuterated chloroform (CDCl3) as the solvent.

[0029] Example 1 The first synthetic route for compound A is as follows:

[0030] The specific preparation method is as follows: (1) Synthesis of compound 2: Under a nitrogen atmosphere, 8-bromo-1-octene (986.09 mg, 5.16 mmol), potassium carbonate (891.41 mg, 6.45 mmol), potassium iodide (214.14 mg, 1.29 mmol), and DMF (60 mL) were added to a 250 mL reaction flask containing compound 1 (1 g, 1.29 mmol). The mixture was heated to 110 °C and reacted for 12 h. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed. The crude product was then purified by silica gel column chromatography to give compound 2 (820 mg, yield 63.8%).

[0031] (2) Synthesis of compound 3: Under a nitrogen atmosphere, Grubbs second-generation catalyst (85.27 mg, 0.10 mmol) and DCM (60 mL) were added to a 100 mL reaction flask containing compound 2 (500 mg, 0.50 mmol). The mixture was heated to 70 °C and reacted for 12 h. The mixture was extracted three times with dichloromethane, dried with anhydrous sodium sulfate, and the solvent was removed. The crude product was then purified by silica gel column chromatography to obtain compound 3 (395 mg, 81.6%).

[0032] (3) Synthesis of compound 4: Under a nitrogen atmosphere, at 0°C, DMF (0.88 mL) was added dropwise to a 10 mL reaction flask containing phosphorus oxychloride (0.29 mL), and the reaction was maintained at 0°C for 40 min. Subsequently, the reaction solution was added dropwise to a 50 mL reaction flask containing compound 3 (200 mg, 0.21 mmol) and 1,2-dichloroethane (20 mL) solution. The reaction was heated to 80°C and reacted for 12 h. The reaction was quenched with saturated anhydrous sodium carbonate solution, extracted three times with dichloromethane, dried with anhydrous sodium sulfate, and the solvent was removed. The crude product was purified by silica gel column chromatography to obtain compound 4 (180 mg, 83.7%).

[0033] (4) Synthesis of compound A: Under a nitrogen atmosphere, 5,6-difluoro-3-(dicyanomethylene)indophenone (224.87 mg, 0.98 mmol), pyridine (0.1 mL), and chloroform (10 mL) were added to a 25 mL reaction flask containing compound 4 (100 mg, 0.098 mmol). The mixture was heated to 70 °C and reacted for 12 h. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed. The crude product was purified by silica gel column chromatography to give compound A (98 mg, 69.1%). The composition of compound A... 1 The H NMR spectrum is shown in [reference]. Figure 1 , 13 See CNMR spectrum Figure 2 Its HRMS map is as follows Figure 3 As shown.

[0034] Example 2 The second synthetic route for compound A is as follows:

[0035] (1) Synthesis of compound 2: Under a nitrogen atmosphere, 8-bromo-1-octene (986.09 mg, 5.16 mmol), potassium carbonate (891.41 mg, 6.45 mmol), potassium iodide (214.14 mg, 1.29 mmol), and DMF (60 mL) were added to a 250 mL reaction flask containing compound 1 (1 g, 1.29 mmol). The mixture was heated to 110 °C and reacted for 12 h. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed. The crude product was then purified by silica gel column chromatography to give compound 2 (820 mg, yield 63.8%).

[0036] (2) Synthesis of compound 5: Under a nitrogen atmosphere, at 0°C, DMF (0.88 mL) was added dropwise to a 10 mL reaction flask containing phosphorus oxychloride (0.29 mL), and the reaction was maintained at 0°C for 40 min. Subsequently, the reaction solution was added dropwise to a 50 mL reaction flask containing compound 2 (210 mg, 0.21 mmol) and 1,2-dichloroethane (20 mL) solution. The reaction was heated to 80°C and reacted for 12 h. The reaction was quenched with saturated anhydrous sodium carbonate solution, extracted three times with dichloromethane, dried with anhydrous sodium sulfate, and the solvent was removed. The crude product was purified by silica gel column chromatography to obtain compound 5 (185 mg, 83.8%).

[0037] (3) Synthesis of compound 6: Under a nitrogen atmosphere, 5,6-difluoro-3-(dicyanomethylene)indoline ketone (393.67 mg, 1.71 mmol), pyridine (0.1 mL), and chloroform (10 mL) were added to a 25 mL reaction flask containing compound 5 (180 mg, 0.17 mmol). The mixture was heated to 70 °C and reacted for 12 h. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed. The crude product was then purified by silica gel column chromatography to obtain compound 6 (175 mg, 69.7%).

[0038] (4) Synthesis of compound A: Under a nitrogen atmosphere, Grubbs second-generation catalyst (20.38 mg, 0.024 mmol) and DCM (10 mL) were added to a 25 mL reaction flask containing compound 6 (170 mg, 0.12 mmol). The mixture was heated to 70 °C and reacted for 12 h. The mixture was extracted three times with dichloromethane, dried with anhydrous sodium sulfate, and the solvent was removed. The crude product was then purified by silica gel column chromatography to obtain compound A (140 mg, 80.6%).

[0039] Example 3: Characterization of Small Molecule Organic Solar Cell Devices Fabrication of binary organic solar cell devices: After ultrasonic cleaning, ITO glass (indium tin oxide conductive glass) is treated with oxygen-plasma. PEDOT:PSS poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (Xi'an Yuri Solar Energy Technology Co., Ltd., PEDOT:PSS AI4083, product number: 306020, a pre-prepared mixed solution) is spin-coated onto the ITO at 5000 rpm. The substrate is then annealed at 150℃ for 15 minutes to obtain a substrate with a surface film thickness of approximately 40 nm.

[0040] Then, the acceptor compound A prepared in Example 1 and the donor D18 (structural formula shown below) were mixed in chloroform to form a blend solution (where the donor concentration was 7 mg / mL and the acceptor concentration was 8.4 mg / mL), and 0.3% (v / v) of diiodomethane was added as an additive. The blend solution was spin-coated at 3000 rpm and annealed at 100°C for 5 minutes, resulting in a film thickness of approximately 100 nm (active material layer). An electron transport layer PDINN (structural formula shown below) was then spin-coated at 3000 rpm, resulting in a film thickness of approximately 10 nm.

[0041] Finally, 70 nm of metallic silver was deposited on the electron transport layer as electrodes. The efficiency of the prepared solar cells is shown in Table 1. All tests were conducted under one sun, i.e., a light intensity of 100 mW / cm². 2One unit of solar irradiance, also called 1 sun, refers to one unit of solar intensity. Under an atmospheric factor of AM 1.5G, the intensity is 96 mW / cm². 2 The intensity of sunlight varies with time, location, and weather conditions. Therefore, the intensity of sunlight will differ under different actual circumstances.

[0042] The equipment used in the laboratory of this invention is a solar simulator, calibrated using silicon solar cells, with a standardized value of 100 mW / cm². 2 .

[0043]

[0044] Table 1. Photovoltaic parameters of OSCs based on compound D18: compound A

[0045] Figure 4 (a) shows the JV curve of the binary organic solar cell device in Example 2, in which donor compound A and donor D18 are mixed as the active layer, measured under simulated sunlight (on a solar simulator (SAN-EI, XES-40S2-CE) at 100 mW / cm²). 2 The current-voltage (JV) characteristics were measured using a Keithley 2450 source meter under an irradiation intensity of (AM 1.5G). Figure 4 (b) shows the external quantum efficiency (EQE) measurement plot: EQE spectra were analyzed using a certified Newport IPCE measurement system. (From Table 1 and...) Figure 4 It can be seen that the combination of donor compound A and D18 donor can produce a highly efficient active layer with a wide process window.

[0046] Figure 5 The UV-Vis spectra of the solution and film were recorded using a Hitachi U-4100 spectrophotometer. The solution absorption test sample was dissolved in chloroform at a concentration of 0.01 mg / mL and measured at room temperature. The optical absorption spectrum of the film was prepared by spin-coating a chloroform solution (5.0 mg / mL, 1500 rpm) onto a quartz plate. The UV-Vis absorption spectrum of compound A was measured using a UV spectrophotometer. Compound A exhibits excellent solubility in widely used organic solvents such as chloroform and tetrahydrofuran at room temperature. Figure 5 The image shows the normalized absorption spectra of compound A in dilute chloroform solution and on a thin film. It can be seen that compound A exhibits strong absorption in the 600-900 nm range.

[0047] For any points not covered above, existing technologies shall apply.

[0048] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A class of receptor materials having locking side chains, characterized in that, The structural formula is shown in Figure A below: 。 2. A method for preparing a receptor material with locking side chains as described in claim 1, characterized in that, Includes the following steps: Step 1: Using compound 1 as a starting material, react with 8-bromo-1-octene to obtain compound 2: ； The structural formula of compound 1 is as follows: ； Step 2: Using compound 2 as a starting material, the reaction proceeds under the action of Grubbs second-generation catalyst to obtain compound 3: ； Step 3: Using compound 3 as a starting material, react with phosphorus oxychloride and DMF to obtain compound 4: ； Step 4: Using compound 4 as a starting material, it is reacted with 5,6-difluoro-3-(dicyanomethylene)indoketone via a Knoevenagel condensation reaction to obtain compound A: 。 3. The preparation method according to claim 2, characterized in that, Step 1 includes: under a nitrogen protective atmosphere, adding 8-bromo-1-octene, potassium carbonate, potassium iodide and DMF to a reaction flask containing compound 1, heating to 110°C and reacting for 12 h, and purifying to obtain compound 2; The molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate, and potassium iodide is 1:(2-6):(3-7):(1-2). Step 2 includes: under a nitrogen protective atmosphere, adding Grubbs second-generation catalyst and DCM to a reaction flask containing compound 2, heating to 70°C and reacting for 12 h, and purifying to obtain compound 3; The molar ratio of compound 2 to the Grubbs second-generation catalyst is 1:(0.1-0.3).

4. The preparation method according to claim 2, characterized in that, Step 3 includes: under a nitrogen atmosphere and at 0°C, adding DMF dropwise to a reaction flask containing phosphorus oxychloride and maintaining the reaction at 0°C for 40 min; then dropping the reaction solution dropwise into a reaction flask containing compound 3 and a solution of 1,2-dichloroethane; heating to 80°C and reacting for 12 h; and purifying to obtain compound 4. The molar ratio of compound 3, phosphorus oxychloride, and DMF is 1:(12-18):(50-60). Step 4 includes: under a nitrogen protective atmosphere, adding 5,6-difluoro-3-(dicyanomethylene)indone, pyridine and chloroform to a reaction flask containing compound 4, heating to 70°C and reacting for 12 h, and purifying to obtain compound A; The molar ratio of compound 4 to 5,6-difluoro-3-(dicyanomethylene)indone is 1:(6-10).

5. The preparation method according to claim 3, characterized in that, In step 1, the molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate, and potassium iodide is 1:4:5:1; In step 2, the molar ratio of compound 2 to the Grubbs second-generation catalyst is 1:0.2; In step 3, the molar ratio of compound 3, phosphorus oxychloride, and DMF is 1:15:55; In step 4, the molar ratio of compound 4 and 5,6-difluoro-3-(dicyanomethylene)indone is 1:

10.

6. A method for preparing a receptor material with locking side chains as described in claim 1, characterized in that, Includes the following steps: Step 1: Using compound 1 as a starting material, react with 8-bromo-1-octene to obtain compound 2: ； The structural formula of compound 1 is as follows: ； Step 2: Using compound 2 as a starting material, compound 5 is obtained by reacting it with phosphorus oxychloride and DMF. ； Step 3: Using compound 5 as a starting material, compound 6 was obtained by Knoevenagel condensation reaction with 5,6-difluoro-3-(dicyanomethylene)indoketone. ； Step 4: Using compound 6 as a starting material, react with Grubbs II catalyst to obtain compound A: 。 7. The preparation method according to claim 6, characterized in that, Step 1 includes: under a nitrogen protective atmosphere, adding 8-bromo-1-octene, potassium carbonate, potassium iodide and DMF to a reaction flask containing compound 1, heating to 110°C and reacting for 12 h, and purifying to obtain compound 2; The molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate, and potassium iodide is 1:(2-6):(3-7):(1-2). Step 2 includes: under a nitrogen protective atmosphere and at 0°C, DMF is added dropwise to a reaction flask containing phosphorus oxychloride and the reaction is maintained at 0°C for 40 min. Then, the reaction solution is added dropwise to a reaction flask containing compound 2 and a solution of 1,2-dichloroethane, and the reaction is heated to 80°C for 12 h. The mixture is then purified to obtain compound 5. The molar ratio of compound 2, phosphorus oxychloride and DMF is 1:(12-18):(50-60); Step 3 includes: under a nitrogen protective atmosphere, adding 5,6-difluoro-3-(dicyanomethylene)indone, pyridine and chloroform to a reaction flask containing compound 5, heating to 70°C and reacting for 12 h, and purifying to obtain compound 6; The molar ratio of compound 5 and 5,6-difluoro-3-(dicyanomethylene)indone is 1:(6-10). Step 4 includes: under a nitrogen protective atmosphere, adding Grubbs second-generation catalyst and DCM to a reaction flask containing compound 6, heating to 70°C and reacting for 12 h, and purifying to obtain compound A; The molar ratio of compound 6 to the Grubbs second-generation catalyst is 1:(0.1-0.3).

8. The preparation method according to claim 7, characterized in that, In step 1, the molar ratio of compound 1, 8-bromo-1-octene, potassium carbonate, and potassium iodide is 1:4:5:1; In step 2, the molar ratio of compound 2, phosphorus oxychloride, and DMF is 1:15:55; In step 3, the molar ratio of compound 5 and 5,6-difluoro-3-(dicyanomethylene)indone is 1:10; The molar ratio of compound 6 and Grubbs second-generation catalyst in step 4 is 1:0.

2.

9. An organic solar cell, characterized in that, The receptor material is the receptor material with locking side chains as described in claim 2.

10. The organic solar cell according to claim 9, characterized in that, The donor material is D18, and its structural formula is as follows: The mass ratio of the donor material to the acceptor material is 1:(1.0-1.5); the thickness of the active layer is 80-150 nm.

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