Polymerizable cross-linked micromolecular non-fullerene receptor and preparation method thereof

Abstract

The invention provides a polymerizable cross-linked micromolecular non-fullerene receptor and a preparation method thereof, and relates to the technical field of organic solar cells, the polymerizable cross-linked micromolecular non-fullerene receptor comprises a receptor molecule, the receptor molecule is formed by connecting at least two terminal receptor elements A and a central donor element D in a conjugated skeleton mode, the terminal acceptor element A is a cyano-substituted indandione derivative. According to the polymerizable cross-linked micromolecular non-fullerene receptor and the preparation method thereof, side chain functionalization and donor skeleton construction are combined into a few steps, so that the synthesis path is greatly simplified, and the purification and separation times of an intermediate are reduced; under the mild Pd (0) and Cu (I) catalytic condition, a polymerization active functional group P can be completely tolerated, side reaction is avoided, and additional protection-deprotection operation is not needed; the whole process steps are concentrated, the accumulative yield is increased by 20%-30% compared with that of a traditional multi-step route, the purity of a final product is larger than or equal to 98%, and efficient preparation can be achieved under conventional laboratory conditions.

Description

Technical Field

[0001] This invention relates to the field of organic solar cell technology, specifically to a polymerizable crosslinkable small molecule non-fullerene acceptor and its preparation method. Background Technology

[0002] Driven by the advantages of wide solar spectrum coverage and low charge carrier recombination loss, polymer solar cells based on narrow-bandgap non-fullerene small molecule acceptors have developed rapidly in recent years, with single-junction power conversion efficiencies exceeding 18%. Typical NFA molecules often employ acceptor-donor-acceptor (A–D–A) or A–D–A–D–A fusion framework structures (such as ITIC and Y6), utilizing intramolecular charge transfer between donor and acceptor units to adjust the spectral absorption range and energy level positions. The π–π stacking of the terminal indanedione acceptor units provides electron transport channels. Typically, the synthetic route first constructs a fusion-ring donor intermediate, then introduces an acceptor unit with an activated methylene terminal (such as 1,1-dicyanbenzylidene indole-3-one) to the molecule's end via Knoevenagel condensation to achieve high-efficiency photoelectric conversion. However, these traditional NFA monomers cannot be further cross-linked and cured after film formation, resulting in film morphology that fluctuates easily with changes in heat, light, or ambient humidity, thus limiting device stability and durability.

[0003] Although some studies have attempted to improve morphological stability by using polymerizable small molecule acceptors or by adding solid additives and solvents, these methods rely on external components or prepolymerized products and cannot fundamentally solve the problems of excessive aggregation of NFA molecules and short device lifetime. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a polymerizable crosslinkable small molecule non-fullerene acceptor and its preparation method. The technical problem to be solved by this invention is: how to achieve high-yield, high-purity preparation with fewer steps by one-step integration and synthesis through side chain functionalization and coupling with the donor backbone, and by having photo / thermal crosslinkable groups.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a polymerizable crosslinkable small molecule non-fullerene receptor, comprising: The receptor molecule is composed of at least two terminal receptor motifs A and a central donor motif D connected in a conjugated backbone manner. The terminal receptor motif A is a cyano-substituted indanedione derivative; The central donor unit D is a fused ring donor unit, the skeleton of which is selected from indododithiophene or dithiophene, and the central donor unit D introduces a polymerizable functional group P at the end of at least one alkyl side chain.

[0006] Preferably, the number of central donor primitives D is one or two.

[0007] Preferably, the terminal acceptor motif A and the central donor motif D are connected by an acetylene bridge, and the polymeric active functional group P is selected from acrylate, methacrylate, alkynyl, maleic anhydride, or styrene groups. The polymeric active functional group P forms a three-dimensional network structure through free radical polymerization crosslinking under ultraviolet light irradiation.

[0008] A method for preparing polymerizable crosslinkable small molecule non-fullerene receptors includes: S1. Take an indolodithiophene or dithiophenothiophene skeleton compound containing a hydroxyl side chain, and halogenate the hydroxyl side chain using a mixture of phosphorus pentachloride and phosphorus trichloride to convert the end of the side chain to bromine or iodine, to obtain a halogenated donor intermediate of general formula I. The yield of this step can reach 85% to 90%. S2. The intermediate of general formula I is reacted with sodium azide in dimethylformamide solution at 60 degrees Celsius for 8 to 12 hours to generate the intermediate of general formula II with azide-terminated side chain. Then, at room temperature, the intermediate of general formula II is reacted with acetylenol acrylate in a 1:1 mixture of THF and water catalyzed by copper sulfate hydrate and reduced ascorbic acid to obtain the intermediate of general formula III with acrylate side chain. S3. The general formula III intermediate, cyanoindanone-phenylboronic acid ester, tetra(triphenylphosphine)palladium(0) catalyst and potassium carbonate were added to a 3:1 mixture of THF and water. The mixture was heated to 75 degrees Celsius and stirred for 6 hours under nitrogen protection to complete the Suzuki coupling reaction and directly construct the A–D–A skeleton general formula IV intermediate containing terminal acceptor units and side chain polymer groups. S4. The intermediate of general formula IV was refluxed with activated methylene indanedione in a mixed solution of piperidine and ethanol for 4 to 5 hours to induce Knoevenagel condensation and generate the target polymerizable crosslinkable small molecule nonfullerene receptor of general formula V. S5. The product of general formula V was subjected to column chromatography using dioxane and ethyl acetate as the mobile phase to obtain a final product with a chemical purity of not less than 98%, and then... 1 H / 13 CNMR, HR-MS, and GPC were used to verify the structure and molecular weight distribution of the final product.

[0009] Preferably, the general formula I is a halogenated donor intermediate, specifically: X–R–D–R–X Wherein, D represents the indododithiophene or dithiophene-dithiophene fused ring conjugated donor skeleton, and R represents C6–C 12 Straight-chain alkyl or alkoxy, where X represents a halogen Br or I; The general formula II is an azide intermediate, specifically: N3–R–D–R–X In general formula I, a terminal halogen X of a side chain is replaced by NaN3 with an azide group N3; The general formula III is a polymeric group-introduced intermediate, specifically: P–R–D–R–X In general formula II, the N3–R side chain is coupled to acetylenic acrylate via the Cu(I) reaction, converting the azide group N3 to the acrylate group P.

[0010] The general formula IV is an intermediate of the A–D–A skeleton, specifically: A—CH=CH—D—CH=CH—A After Suzuki coupling of general formula III with cyanoindanedione-phenylboronic acid ester, a terminal acceptor unit A is attached to each end of the donor backbone D, and the side chain carries a P group.

[0011] Preferably, the receptor molecule is irradiated with light of wavelength 365 nm for 10–15 minutes, causing the polymeric active functional group P to undergo free radical chain polymerization and crosslinking. The optical absorption range of the receptor molecule is 650 nm–920 nm, and the optical band gap is 1.40 eV–1.45 eV.

[0012] Preferably, the side chain is C6–C. 12 Straight-chain alkoxy groups.

[0013] Preferably, the general formula V is a ultimately polymerizable crosslinkable small molecule non-fullerene receptor, specifically: A—CH=CH—D—CH=CH—A After Knoevenagel condensation, the terminal acceptor unit A and the donor D are connected by a double bond to form a complete A–D–A structure. The side chain R–P retains acrylate or other polymerizable functional groups for subsequent spontaneous crosslinking.

[0014] This invention provides a polymerizable crosslinkable small molecule non-fullerene receptor and its preparation method. It has the following beneficial effects: This polymerizable crosslinkable small molecule nonfullerene acceptor and its preparation method greatly simplify the synthetic route by combining side chain functionalization and donor backbone construction into a few steps, reducing the number of intermediate purification and separation steps. Under mild Pd(0) and Cu(I) catalytic conditions, the polymerizable active functional group P can be completely tolerated without side reactions, and no additional protection-deprotection operation is required. The overall process steps are concentrated, and the cumulative yield is 20%–30% higher than that of the traditional multi-step route, and the purity of the final product is ≥98%, which can be efficiently prepared under conventional laboratory conditions.

[0015] The designed acceptor monomer has photo / thermal crosslinking groups such as acrylate, styrene, or maleic anhydride. After film formation, no external crosslinking agent or prepolymer product is needed. It can form a three-dimensional crosslinked network through ultraviolet light irradiation or heat treatment, which fundamentally inhibits the excessive aggregation of small molecule non-fullerene acceptors, significantly improves the morphological stability of the active layer film, and enables the device to maintain a photoelectric conversion efficiency of more than 90% under long-term aging (≥1000h) or high-temperature annealing (≥120℃) conditions. It also has a broad spectrum absorption of 650–920nm and excellent energy level matching characteristics, which significantly extends the service life of organic solar cells. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the process of implementing an invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: D=1 like Figure 1 As shown, this embodiment of the invention provides a polymerizable crosslinkable small molecule non-fullerene receptor, comprising a main chain structure: A–D–A architecture, wherein the terminal receptor motif A is a cyano-substituted indanedione derivative, which is sequentially linked to the central donor motif D via α,β-unsaturated double bonds (–CH=CH–).

[0019] Central donor motif D: indo-dithiophene fusion conjugated framework.

[0020] Side chain structure: The D backbone is connected to n-octyloxy groups (–O–C8H) at positions 2 and 6 respectively. 17 The side chain ends are connected to the polymerizable active functional group acrylate group (–COO–CH=CH2) via ester bonds.

[0021] Crosslinking triggering conditions: The acrylate groups are irradiated with 365nm ultraviolet light for 10 minutes, and crosslinked through free radical chain polymerization to form a three-dimensional network structure without the need for external crosslinking agents.

[0022] A method for preparing polymerizable crosslinkable small molecule non-fullerene receptors includes: S1. Take 10.0 g of an indolodithiophene skeleton compound containing an octyl side chain, dissolve it in 100 mL of anhydrous dichloromethane, add phosphorus pentachloride and phosphorus trichloride (mass ratio 3:2), stir the reaction at room temperature for 4 hours to convert the terminal hydroxyl group of the side chain into a bromine substituent, and obtain a halogenated donor intermediate.

[0023] S2. The product from S1 was transferred to 80 mL of N,N-dimethylformamide, and sodium azide (3 molar equivalents) was added. The mixture was stirred at 60 °C for 10 hours to introduce the azide group. After filtering the intermediate, it was transferred to a mixed solvent of tetrahydrofuran:water = 1:1 (volume ratio, 100 mL). Copper sulfate pentahydrate (5 mol%) and ascorbic acid (10 mol%) were added. Ethynyl acrylate (1.2 molar equivalents) was added at room temperature, and the mixture was stirred for 2 hours to complete the azide-yne ​​"click" coupling and introduce the acrylate group, thus obtaining the P-functionalized donor intermediate.

[0024] S3. The S2 intermediate, organoboroester type cyanoindanedione acceptor (2.2 molar equivalents), potassium carbonate (3 molar equivalents) and tetra(triphenylphosphine)palladium(0) catalyst (5 mol%) were added to a mixed solvent of tetrahydrofuran:water = 3:1 (volume ratio, 120 mL in total). The mixture was heated to 75 °C and stirred for 6 hours under nitrogen protection to complete the main chain C–C coupling and obtain the A–D–A skeleton intermediate.

[0025] S4. Dissolve the product of S3 in a mixed solution of piperidine:ethanol = 1:10 (volume ratio, 100 mL in total), heat under reflux for 5 hours to allow the terminal indanedione to undergo α,β-unsaturated condensation with the donor backbone to generate a complete polymerizable crosslinkable acceptor molecule.

[0026] S5. The product from S4 was subjected to silica gel column chromatography (eluent: hexane: ethyl acetate = 4:1) and recrystallized to obtain a final product with a chemical purity ≥ 98%; 1 HNMR, 13 Its structure and molecular weight distribution were verified by CNMR, high-resolution mass spectrometry (HR-MS), and gel permeation chromatography (GPC).

[0027] Example 2: D=2 like Figure 1 As shown, this embodiment of the invention provides a polymerizable crosslinkable small molecule non-fullerene receptor, comprising: a main chain structure: A–D–A–D–A architecture, wherein the three terminal receptor motifs A are cyano-substituted indanedione derivatives and are interconnected by α,β-unsaturated double bonds (–CH=CH–); and the two central donor motifs D are both indole-dithiophene-thiophene fusion conjugated backbones.

[0028] Side chain structure: Each D backbone has an octyl group (–O–C8H) attached at positions 2 and 6. 17The side chain ends are connected to acrylate groups (–COO–CH=CH2)P via ester bonds.

[0029] Crosslinking triggering conditions: P undergoes free radical polymerization crosslinking when exposed to 365nm ultraviolet light for 10–15 minutes or heat-treated at 100–120℃ for 20–30 minutes.

[0030] A method for preparing polymerizable crosslinkable small molecule non-fullerene receptors includes: S1. Take 10.0 g of an indolodithiophene thiophene skeleton compound containing an octyl group side chain, dissolve it in 100 mL of anhydrous dichloromethane, add phosphorus pentachloride and phosphorus trichloride (mass ratio 3:2), stir at room temperature for 4 hours to complete the conversion of the terminal hydroxyl group of the side chain to bromine, and obtain the dibromo-substituted donor intermediate.

[0031] S2. Dissolve the product of S1 in 80 mL of N,N-dimethylformamide, add sodium azide (3 molar equivalents), stir at 60 °C for 10 hours to introduce the azide group; after filtration, transfer the intermediate obtained to a mixed solvent of tetrahydrofuran:water = 1:1 (volume ratio, 100 mL in total), add copper sulfate pentahydrate (5 mol%) and ascorbic acid (10 mol%), add ethynyl acrylate (1.2 molar equivalents) at room temperature, stir for 2 hours to introduce the acrylate group P, and obtain the functionalized dibromo intermediate.

[0032] S3. The S2 intermediate (1 equivalent), organoboroester type indanedione acceptor (3.3 equivalent), potassium carbonate (4 molar equivalents) and tetra(triphenylphosphine)palladium(0) catalyst (6 mol%) were dissolved in a tetrahydrofuran:water = 3:1 (volume ratio, 150 mL in total). The mixture was heated to 80 °C and stirred for 8 hours under nitrogen protection to construct the A–D–A–D–A framework intermediate in one pot.

[0033] S4. Dissolve the product of S3 in a mixed solution of piperidine:ethanol = 1:10 (volume ratio, 120 mL in total), heat under reflux for 4 hours to introduce terminal double bonds and generate a complete polymerizable crosslinkable acceptor molecule.

[0034] S5. The product from S4 was subjected to silica gel column chromatography (eluent: hexane: ethyl acetate = 4:1) and recrystallized to obtain a final product with a purity ≥ 98%; 1 HNMR, 13 CNMR, HR-MS and GPC verified its structure and molecular weight distribution; UV-Vis absorption is in the range of 650–920 nm, and the optical band gap is about 1.38 eV; the film morphology retention rate is >94% after 10 minutes of 365 nm UV irradiation.

[0035] Example 3: D=1 like Figure 1As shown, this embodiment of the invention provides a polymerizable crosslinkable small molecule non-fullerene receptor, comprising: a main chain structure: an A–D–A architecture, wherein the terminal receptor motif A is a cyano-substituted indanedione derivative, which is linked to the center D via –CH=CH–; and the center D is an indole-dithiophene skeleton.

[0036] Side chain structure: The D backbone is connected to n-octyloxy side chains (–O–C8H) at positions 2 and 6. 17 The side chain ends are connected to a styrenyl group (–COO–C6H4–CH=CH2)P via an ester bond.

[0037] Crosslinking characteristics: P crosslinks through free radical polymerization under 365nm ultraviolet irradiation for 10–15 minutes without the need for external additives.

[0038] A method for preparing polymerizable crosslinkable small molecule non-fullerene receptors includes: S1. Under the same conditions as in Example 1, S1, a halogenated donor intermediate was obtained.

[0039] S2. Dissolve intermediate S1 in a mixed solvent of pyridine:triethylamine = 1:1 (volume ratio, 100 mL in total), slowly add 4-vinylbenzoyl chloride (1.2 molar equivalents), stir at room temperature for 5 hours, introduce styrene group P, and obtain functionalized intermediate.

[0040] S3. Under the same conditions as in Example 1, S3, the functionalized intermediate was coupled with cyanoindanedione borate, potassium carbonate and tetra(triphenylphosphine)palladium(0) in tetrahydrofuran:water = 3:1 at 75°C for 6 hours to construct the A–D–A skeleton intermediate.

[0041] S4. Under the same conditions as in Example 1, S4, reflux for 5 hours to introduce terminal double bonds and generate the target receptor molecule.

[0042] S5. Purify under the same conditions as in Example 1, S5, with a final product purity ≥98%; UV-Vis absorption 660–880 nm, optical band gap 1.43 eV; film morphology retention >93% after 12 minutes of 365 nm UV irradiation.

[0043] Example 4: D=2 like Figure 1 As shown, this embodiment of the invention provides a polymerizable crosslinkable small molecule non-fullerene receptor, comprising a main chain structure: A–D–A–D–A architecture, where the three terminal receptor motifs A are cyanoindanedione derivatives and the two central donor motifs D are indododithiophene-thiophene skeletons, connected by –CH=CH–.

[0044] Side chain structure: Each D backbone has a hexyloxy group (–O–C6H) attached at positions 2 and 6. 13The side chain has a maleic anhydride group (–CO–C4H2O3)P connected to its end by an ester bond, for a total of four P groups.

[0045] Crosslinking method: P undergoes ring-opening polymerization crosslinking under heat treatment at 120℃ for 30 minutes, without the need for external additives.

[0046] A method for preparing polymerizable crosslinkable small molecule non-fullerene receptors includes: S1. Under the same conditions as in Example 2, S1, a dibromo-D unit intermediate was obtained.

[0047] S2. Dissolve intermediate S1 in 80 mL of N,N-dimethylformamide, add maleic anhydride (2.5 molar equivalents) and triethylamine (3 molar equivalents), stir at 60 °C for 8 hours, introduce maleic anhydride P, and obtain the functionalized intermediate.

[0048] S3. The intermediate S2 (1 equivalent), cyanoindanone borate (3.3 equivalents), potassium carbonate (4 equivalents) and tetra(triphenylphosphine)palladium (0) catalyst (6 mol%) were added to a mixed solvent of tetrahydrofuran:water = 3:1 (volume ratio, 150 mL in total). The mixture was stirred at 80 °C for 8 hours under nitrogen protection to construct the A–D–A–D–A framework intermediate in one pot.

[0049] S4. Dissolve the product of S3 in a mixed solution of piperidine:ethanol = 1:10 (volume ratio, 120 mL in total), reflux for 5 hours to introduce terminal double bonds and obtain the complete acceptor molecule.

[0050] S5. The product from S4 was subjected to silica gel column chromatography (hexane:ethyl acetate = 4:1) and recrystallized to obtain a final product with a purity ≥ 98%; 1 HNMR, 13 CNMR, HR-MS and GPC confirmed its structure and molecular weight distribution; the UV-Vis absorption range is 650–910 nm, and the optical band gap is 1.38 eV; the film stability was improved by 30% after heat treatment at 120℃ for 30 minutes.

[0051] Example 5 (D quantity is 1; D skeleton is indolothiophene; P is methacrylate group) I. Compound Composition Main chain structure: A–D–A architecture, with terminal acceptor motif A being a cyano-substituted indanedione derivative, which is linked to the central donor motif D via –CH=CH–; Central donor motif D: indothiophene fusion conjugated framework; Side chain structure: The D backbone is attached to n-octyloxy groups (–O–C8H) at positions 2 and 6. 17 The side chain ends are connected to methacrylate groups (–COO–C(CH3)=CH2)P via ester bonds; Crosslinking triggering conditions: P undergoes spontaneous free radical polymerization crosslinking under the conditions of 365nm ultraviolet irradiation for 10 min or heat treatment at 100℃ for 20 min.

[0052] II. Preparation Method S1 halogenation 10.0 g of indo-dithiophene-octyloxy skeleton compound was dissolved in 100 mL of anhydrous dichloromethane, and PCl5:PCl3 = 3:2 (mass ratio) was added. The mixture was stirred at room temperature for 4 h to obtain a 2,6-dibromo intermediate.

[0053] S2 esterification introduces methacrylate groups. The S1 product was dissolved in pyridine:triethylamine = 1:1 (volume ratio, 100 mL in total), and methacryloyl chloride (1.2 eq) was added dropwise. The mixture was stirred at room temperature for 5 h to obtain a side-chain methacrylate functionalized intermediate.

[0054] S3Suzuki Couplet The S2 product, organoboroester type cyanoindanedione acceptor (2.2 eq), K2CO3 (3 eq), and Pd(PPh3)4 (5 mol%) were added to THF:water = 3:1 (120 mL), and stirred at 75 °C for 6 h under N2 protection to construct the A–D–A backbone.

[0055] S4Knoevenagel condensation The S3 product was dissolved in piperidine:EtOH = 1:10 (100 mL) and refluxed for 5 h to complete the formation of terminal double bonds, thus obtaining a polymerizable crosslinkable acceptor.

[0056] S5 purification characterization Column chromatography (hexane:ethyl acetate = 4:1) + recrystallization, product purity ≥ 98%; structure confirmed by NMR, HR-MS, and GPC.

[0057] Example 6 (D quantity is 1; D skeleton is indolothiophene; P is alkynyl group) I. Compound Composition Main chain structure: Same as in Example 5; Central donor motif D: indothiophene skeleton; Side chain structure: The D skeleton is connected to n-octyloxy groups at positions 2 and 6, with alkynyl groups (–O–C8H) attached to the end of the side chain via ether bonds. 17 –C≡CH)P; Crosslinking triggering conditions: P crosslinks through [2+2] photo-atom addition or thermal induction under 365nm ultraviolet light or 80℃ heat treatment.

[0058] II. Preparation Method S1 halogenation Same as Example 5 S1, yielding a 2,6-dibromo intermediate.

[0059] S2 nucleophilic substitution introduces an alkynyl group. The S1 product was dissolved in 100 mL of THF, and NaH (2 eq) was added to activate the side chain hydroxyl group. The mixture was stirred at room temperature for 0.5 h, and then 1-butyn-1-ol (1.2 eq) was added dropwise. The mixture was stirred for another 4 h to generate a side chain alkynyl functionalized intermediate.

[0060] S3Suzuki Couplet As in Example 5 S3, construct the A–D–A skeleton intermediate.

[0061] S4Knoevenagel condensation Same as Example 5 S4, to obtain the complete receptor molecule.

[0062] S5 purification characterization Same as Example 5 S5, the product purity is ≥98%; after the film is irradiated at 365nm for 10min or heat-treated at 80℃ for 30min, a cross-linked network is formed, and the morphology retention rate is >95%.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A polymerizable cross-linkable small molecule non-fullerene receptor, characterized in that, include: The receptor molecule is composed of at least two terminal receptor motifs A and a central donor motif D connected in a conjugated backbone manner. The terminal receptor motif A is a cyano-substituted indanedione derivative; The central donor unit D is a fused ring donor unit, the skeleton of which is selected from indododithiophene or dithiophene, and the central donor unit D introduces a polymerizable functional group P at the end of at least one alkyl side chain.

2. The polymerizable crosslinkable small molecule non-fullerene receptor according to claim 1, characterized in that: The number of central donor primitives D is one or two.

3. The polymerizable crosslinkable small molecule non-fullerene receptor according to claim 1, characterized in that: The terminal acceptor motif A and the central donor motif D are connected by an acetylene bridge. The polymeric active functional group P is selected from acrylate, methacrylate, alkynyl, maleic anhydride, or styrene groups. The polymeric active functional group P forms a three-dimensional network structure through free radical polymerization crosslinking under ultraviolet light irradiation.

4. A method for preparing polymerizable cross-linkable small molecule non-fullerene receptors, characterized in that, include: S1. Take an indolodithiophene or dithiophenothiophene skeleton compound containing a hydroxyl side chain, and halogenate the hydroxyl side chain using a mixture of phosphorus pentachloride and phosphorus trichloride to convert the end of the side chain to bromine or iodine, to obtain a general formula I halogenated donor intermediate. S2. The intermediate of general formula I is reacted with sodium azide in dimethylformamide solution at 60 degrees Celsius for 8 to 12 hours to generate the intermediate of general formula II with azide-terminated side chain. Then, at room temperature, the intermediate of general formula II is reacted with acetylenol acrylate in a 1:1 mixture of THF and water catalyzed by copper sulfate hydrate and reduced ascorbic acid to obtain the intermediate of general formula III with acrylate side chain. S3. The general formula III intermediate, cyanoindanone-phenylboronic acid ester, tetra(triphenylphosphine)palladium(0) catalyst and potassium carbonate were added to a 3:1 mixture of THF and water. The mixture was heated to 75 degrees Celsius and stirred for 6 hours under nitrogen protection to complete the Suzuki coupling reaction and directly construct the A–D–A skeleton general formula IV intermediate containing terminal acceptor units and side chain polymer groups. S4. The intermediate of general formula IV was refluxed with activated methylene indanedione in a mixed solution of piperidine and ethanol for 4 to 5 hours to induce Knoevenagel condensation and generate the target polymerizable crosslinkable small molecule nonfullerene receptor of general formula V. S5. The product of general formula V was subjected to column chromatography with dioxane and ethyl acetate as the mobile phase to obtain a final product with a chemical purity of not less than 98%, and then... 1 H / 13 CNMR, HR-MS, and GPC were used to verify the structure and molecular weight distribution of the final product.

5. The method for preparing a polymerizable crosslinkable small molecule non-fullerene receptor according to claim 4, characterized in that: The general formula I is a halogenated donor intermediate, specifically: X–R–D–R–X Wherein, D represents the indododithiophene or dithiophene-dithiophene fused ring conjugated donor skeleton, and R represents C6–C 12 Straight-chain alkyl or alkoxy, where X represents a halogen Br or I; The general formula II is an azide intermediate, specifically: N3–R–D–R–X In general formula I, a terminal halogen X of a side chain is replaced by NaN3 with an azide group N3; The general formula III is a polymeric group-introduced intermediate, specifically: P–R–D–R–X In general formula II, the N3–R side chain is coupled to acetylenic acrylate via the Cu(I) reaction, converting the azide group N3 to the acrylate group P.

6. The general formula IV is an intermediate of the A–D–A skeleton, specifically as follows: A—CH=CH—D—CH=CH—A After Suzuki coupling of general formula III with cyanoindanedione-phenylboronic acid ester, a terminal acceptor unit A is attached to each end of the donor backbone D, and the side chain carries a P group.

7. The method for preparing a polymerizable crosslinkable small molecule non-fullerene receptor according to claim 4, characterized in that: When the acceptor molecule is irradiated with light at a wavelength of 365 nm for 10–15 minutes, the polymeric active functional group P undergoes free radical chain polymerization and cross-linking. The optical absorption range of the acceptor molecule is 650 nm–920 nm, and the optical band gap is 1.40 eV–1.45 eV.

8. The method for preparing a polymerizable crosslinkable small molecule non-fullerene receptor according to claim 4, characterized in that: The side chain is C6–C. 12 Straight-chain alkoxy groups.

9. The method for preparing a polymerizable crosslinkable small molecule non-fullerene receptor according to claim 4, characterized in that: The general formula V is a ultimately polymerizable crosslinkable small molecule non-fullerene acceptor, specifically: A—CH=CH—D—CH=CH—A After Knoevenagel condensation, the terminal acceptor unit A and the donor D are connected by a double bond to form a complete A–D–A structure, while the side chain R–P retains the acrylate or other polymerizable functional groups.

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