A class of polymeric photoactive materials containing thermally defunctionalized functional groups and flexible segments, and their preparation and application.

Abstract

This invention belongs to the field of organic optoelectronic technology, and discloses a class of polymer photoactive materials containing thermally desorbable functional groups and flexible segments, as well as their preparation and application. The structure of the polymer photoactive material containing thermally desorbable functional groups and flexible segments is shown in Formula I below. In Formula I, at least one unit among the D unit, A unit, and flexible segment contains a thermally desorbable group, and the number of thermally desorbable groups on each unit containing the thermally desorbable group is 1 to 4, relatively independently. These polymers have good solubility and can be processed into smooth films through solution processing. Furthermore, at the thermal desorption annealing temperature (T... a Additional heat treatment of the resulting film leads to the removal of thermally desorbed groups, thereby eliminating its strong solubility in organic solvents and making it a solvent-resistant layer that will not be corroded by the solution processing of the remaining layers, thus providing a guarantee for subsequent lamination processing.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic technology, specifically relating to a class of polymer photoactive materials containing thermally desorbable functional groups and flexible segments, and their preparation and application. Background Technology

[0002] Solution-processed conjugated polymers have attracted much attention due to their ease of use and compatibility in photovoltaic device fabrication.

[0003] Solution processing of conjugated polymers typically involves spin coating, inkjet printing, or blade coating, all of which require good solubility of the optoelectronic semiconductor polymer in the processing solvent. However, the rigid backbone of conjugated polymers hinders their solubility in organic solvents, necessitating the addition of solubilizing side groups, such as aliphatic, ether, or ester components. 3 The side chains of hybrid carbon atoms weaken absorption, hinder charge carrier transport, and negatively impact photochemical stability. Therefore, a crucial issue is how to achieve appropriate molecular ordering and maintain certain charge carrier transport characteristics through the rational design of side groups, without sacrificing solubility, thereby resolving the trade-off between conjugated structure and solution processability. Summary of the Invention

[0004] The primary objective of this invention is to provide a class of polymeric photoactive materials containing thermally removable functional groups and flexible segments for organic photovoltaic devices. These polymeric photoactive materials with thermally removable functional groups and flexible segments exhibit a low glass transition temperature, superior photovoltaic performance, and are suitable for solution processing of solvent-resistant layers, demonstrating significant application potential.

[0005] Another object of the present invention is to provide a method for preparing and controlling the aforementioned polymer photoactive material containing thermally deactivated functional groups and flexible segments.

[0006] This invention also provides applications of the aforementioned polymeric photoactive materials containing thermally deactivated functional groups and flexible segments. These polymeric materials can be used in organic solar cells, organic photodetectors, organic field-effect transistors, organic light-emitting diodes, etc.

[0007] Another object of the present invention is to provide a method for preparing a device solution containing the aforementioned polymer photoactive material with thermally desorbable functional groups and flexible segments.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A class of polymeric photoactive materials containing thermally desorbable functional groups and flexible segments have the structure shown in Formula I below:

[0010]

[0011] In Formula I, the design of the flexible segment follows the following chemical structural formula, which is Formula II, where C n This includes, but is not limited to, straight-chain, branched-chain, or heteroatom-branched hydrocarbons with 2 to 12 carbon atoms bearing an R3 substituent, preferably -C8H. 16 One of -, -C2H2-, -C3H6N(R3)C3H6-; Ar is an aromatic ring having 4 to 8 carbon atoms, a heteroarylalkyl ring having 4 to 8 carbon atoms, an aryloxy ring having 4 to 8 carbon atoms, a heteroaryloxy ring having 4 to 8 carbon atoms, an arylalkoxy ring having 4 to 8 carbon atoms, or a heteroarylalkoxy ring having 4 to 8 carbon atoms, preferably thiophene.

[0012]

[0013] In Formula I, the D unit is an electron donor unit, including but not limited to one of the following structural formulas:

[0014]

[0015] In Formula I, unit A is an electron acceptor unit, including but not limited to one of the following structural formulas:

[0016]

[0017] In Formula I, the D unit, A unit, and the structural formula of the flexible segment, R1, R2, R3, R4, and R5, are relatively independently hydrogen atoms. The thermally removed groups are -(C=O)-OC(CH3)3, halogen-substituted or unsubstituted straight-chain alkyl, branched alkyl, alkoxy, or alkylthio groups having 1–27 carbon atoms; halogen-substituted or unsubstituted straight-chain alkenyl, branched alkenyl, cyclic alkenyl, alkenoxy, or alkenthio groups having 4–27 carbon atoms; halogen-substituted or unsubstituted straight-chain, branched, or cyclic alkynyl groups having 4–27 carbon atoms; halogen-substituted or unsubstituted straight-chain, branched, or cyclic alkyl carbonyl groups having 4–27 carbon atoms; halogen-substituted or unsubstituted aryl groups having 4–27 carbon atoms; and halogen-substituted... One of the following: an unsubstituted heteroaryl group having 4 to 27 carbon atoms; a halogenated or unsubstituted aralkyl group having 4 to 27 carbon atoms; a halogenated or unsubstituted heteroarylalkyl group having 4 to 27 carbon atoms; a halogenated or unsubstituted aryloxy group having 4 to 27 carbon atoms; a halogenated or unsubstituted heteroaryloxy group having 4 to 27 ring atoms; a halogenated or unsubstituted arylalkoxy group having 4 to 27 carbon atoms; or a halogenated or unsubstituted heteroarylalkoxy group having 4 to 27 carbon atoms; at least one of the D unit, A unit, and flexible segment in Formula I contains a thermally desorbable group, and the number of thermally desorbable groups on each unit containing the thermally desorbable group is 1 to 4, which are relatively independent.

[0018] In Formula I, x = 0% to 30%, preferably 5% to 30%, and n = 2 to 300.

[0019] Preferably, the above-mentioned polymer photoactive material containing thermally desorbable functional groups and flexible segments has the following structure:

[0020]

[0021]

[0022] Where x = 0% to 30%, preferably 5% to 30%, and n = 2 to 300.

[0023] A method for preparing and controlling the above-mentioned polymer photoactive material containing thermally deactivated functional groups and flexible segments includes the following steps:

[0024] In an inert gas atmosphere and organic solvent, monomers containing the aforementioned flexible segment units, monomers containing electron donor units (i.e., D units), and monomers containing electron acceptor units (i.e., A units) are mixed. At least one of these monomers contains thermally defunctionalized groups. Depending on the material's solubility, the x value in the copolymer structure is set between 0% and 30%, and the content of thermally defunctionalized groups (the number of thermally defunctionalized groups divided by the number of repeating units n) is set between 2 and 4. Polymerization is then carried out under the catalysis of a catalyst. After purification, the polymer active layer material containing thermally defunctionalized groups and flexible segments is obtained. The material T is adjusted by controlling the proportion of flexible unit monomers. g By adjusting the proportion of functional groups in the monomer to be thermally desorbed, the material can reach the thermal desorption temperature T. a The solubility after T f (Device operating temperature) < T g (glass transition temperature) < T a (Heat removal annealing temperature).

[0025] The organic solvent may be one of chlorobenzene, dichlorobenzene, toluene, or xylene; the catalyst is a palladium catalyst, which may be one of tetraphenylphosphine palladium, palladium acetate, or tris(dibenzylacetone)dipalladium; the sum of the amounts of the reactive functional groups of the monomer containing flexible segment units and the monomer containing electron donor units is equal to the amount of the reactive functional groups of the monomer containing electron acceptor units.

[0026] The polymerization reaction is carried out at a temperature of 110–140°C, for a reaction time of 40–60 h, and at a stirring rate of 200–1000 rpm.

[0027] The mixing method is physical mixing; the purification method includes one or more of precipitation, filtration, column chromatography and extraction.

[0028] The active layer material for photovoltaic devices containing thermally desorbable functional groups and flexible segment polymers of the present invention is prepared via a Stille coupling reaction, and the reaction equation is as follows:

[0029]

[0030] The aforementioned polymer photoactive materials containing thermally deactivated functional groups and flexible segments are used in organic photovoltaic devices, especially in organic solar cells, organic photodetectors, organic field-effect transistors, and organic light-emitting diodes.

[0031] A solution processing method for an organic photovoltaic device comprising the aforementioned polymer photoactive material with thermally desorbable functional groups and flexible segments includes the following steps: dissolving the polymer photoactive material with thermally desorbable functional groups and flexible segments in an organic solvent to obtain a solution; obtaining a flat film through solution processing; and then performing a thermal desorption annealing at a temperature (T0).a The resulting film is heat-treated to remove thermally desorbed groups, thereby losing its strong solubility in organic solvents and becoming a solvent-resistant layer. The film morphology is then self-leveled. A mixed solution of the corresponding polymeric photoactive material (x=0) and acceptor is then spin-coated onto the solvent-resistant layer. While maintaining the conjugated properties of the polymeric photoactive material (x=0), a solvent-resistant thin film donor layer with a smooth morphology is obtained, forming a half-planar heterojunction / half-bulk heterojunction device structure that prevents contact between the acceptor and anode.

[0032] The organic solvent is at least one of 2-methyltetrahydrofuran, chloroform, and chlorobenzene;

[0033] The heat treatment refers to annealing at 150-230℃ for 10-60 minutes;

[0034] The receptor is preferably N2200;

[0035] The solvent for the mixed solution is at least one of 2-methyltetrahydrofuran, chloroform, and chlorobenzene.

[0036] Research on narrow bandgap photovoltaic active polymers generally employs a donor-acceptor (DA) structure, typically with alternating electron-rich donor and electron-deficient acceptor units forming the polymer molecular backbone. This invention application protects a series of methods that utilize thermal defunctionalization of groups and flexible segments to adjust the glass transition temperature (Tg). g Methods for preparing and regulating semiconductor copolymers, and methods for regulating the formation of solvent-resistant layers by annealing during device processing using thermal de-grouping.

[0037] These flexible polymers exhibit good solubility, enabling the production of smooth films through solution processing. Further processing is then carried out at the thermal removal annealing temperature (T...). a Additional heat treatment of the resulting film leads to the removal of thermally desorbable groups, thereby eliminating its strong solubility in organic solvents and transforming it into a solvent-resistant layer. This prevents corrosion from the solution processing of other layers, ensuring the smooth transition to subsequent lamination. Through precise control of flexible segments and processing conditions, T... g Reaching below T a And higher than the device operating temperature (T f The level of this technology enables flexible polymer films to possess self-leveling and self-healing properties during thermal stripping, overcoming the devastating damage to film morphology caused by traditional thermal stripping methods.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] (1) The present invention can adjust the structural properties of polymers such as glass transition temperature by selecting different types and amounts of flexible units to meet the needs of different scenarios;

[0040] (2) The present invention can control the polymer solubility and solvent resistance after thermal removal by the content of thermally removed groups;

[0041] (3) Through T a and T g Precise modulation allows the thermally removed polymer to undergo a thermal removal process above its glass transition temperature, enabling the polymer layer to possess self-leveling and self-healing properties and adjusting the microstructure of the thermally removed polymer film. Attached Figure Description

[0042] Figure 1 The results are differential scanning calorimetry analysis of P4 polymer with different proportions of flexible segments.

[0043] Figure 2 The current density-voltage characteristic curves of the P4 device and the control group device are shown.

[0044] Figure 3 The external quantum efficiency-wavelength response curves are shown for the P4 device and the control group device.

[0045] Figure 4 The dark current-voltage curves are for the P4 device and the control group device. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto. Unless otherwise specified, specific conditions in the embodiments shall be performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products. Unless otherwise specified, all reagents used in the embodiments can be purchased from the market.

[0047] Example 1: Preparation of P1 material containing thermally deactivated functional groups and flexible segment polymer active layer

[0048] (1) Preparation of compound 1

[0049] In a dried 100 mL three-necked round-bottom flask, 6,6'-dibromoindigo (1.26 g, 3 mmol) was added and dissolved in 30 mL of dichloromethane. The resulting solution was purged with argon for 20 min. Dimethylaminopurine (37 mg, 0.3 mmol) was added, and the reaction mixture was stirred at room temperature under an argon atmosphere for 30 min. Then, di-tert-butyl dicarbonate (1.44 g, 6.6 mmol) was added, and the mixture was stirred at room temperature for 24 h. The reaction mixture was filtered to obtain a faint red solid, which was washed three times with methanol. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After removing the organic solvent by vacuum drying, 1.44 g of compound 1 red powder was given, with a yield of 77%. 1¹H NMR and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR (500MHz, DMSO-d6) δ8.21(d,2H),8.04(d,2H),7.68(dd,2H),1.58(m,18H).

[0050] (2) Preparation of compound 2

[0051] In a dried 100 mL three-necked round-bottom flask, compound 1 (0.63 g, 1.02 mmol) and 2-tributyltinylthiophene (0.95 g, 1.02 mmol) were added and dissolved in 30 mL of ultra-dry tetrahydrofuran. The resulting solution was purged with nitrogen for 20 min. Tris(dibenzylacetone)dipalladium(0) (3.5 mg) and tris(o-tolyl)phosphine (10 mg) were added, and the reaction mixture was bubbled with nitrogen for 20 min. The mixture was stirred at 80 °C for 4 h. The mixture was then cooled to room temperature and poured into water. The organic phase was extracted with dichloromethane, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After removing the organic solvent by vacuum drying, 0.45 g of compound 2 brown powder was obtained, with a yield of 72%. 1 ¹H NMR and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.96(d,4H),7.71(d,2H),7.59(d,2H),7.54(d,2H),7.17(d,2H),1.59(m,18H).

[0052] (3) Preparation of monomer M1

[0053] At room temperature, N-bromosuccinimide (NBS) (0.683 g, 3.84 mmol) was added in five portions over two hours to a tetrahydrofuran (60 mL) solution of compound 2 (1.0 g, 1.60 mmol). The mixture was stirred at 30 °C for 4 hours and then poured into water. The organic phase was extracted with diethyl ether, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. 1.06 g of a brown solid was given, with a yield of 84%. 1 ¹H NMR and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.96(m,4H),7.71(d,2H),7.19(d,2H),7.09(d,2H),1.59(m,18H).

[0054]

[0055] (4) Preparation of compound 3

[0056] Thiophene (10 g, 118.85 mmol) was weighed and added to a 100 mL two-necked round-bottom flask. Nitrogen gas was introduced, followed by the addition of 30 mL of anhydrous tetrahydrofuran. The flask was placed in a cold trap at -78 °C and cooled for 30 minutes. Then, 2.5 M n-butyllithium solution (38.03 mL, 95.08 mmol) was added dropwise to the reaction flask, and the reaction was continued for another 30 minutes. The refrigeration was then turned off, and the temperature was restored to 25 °C for 2 hours. The temperature was lowered to -78 °C again, and after reacting for 30 minutes, 1,8-dibromooctane (12.93 g, 47.54 mmol) was added dropwise. After the addition was complete, the temperature was restored to 25 °C, and the reaction was continued for another 3 hours. Post-reaction treatment: A small amount of deionized water was added to quench the reaction. The reaction solution was then poured into a beaker containing 200 mL of saturated ammonium chloride aqueous solution, extracted with petroleum ether, washed with deionized water, and the extraction was repeated three times. The solution was dried over anhydrous magnesium sulfate, filtered, and the petroleum ether was removed using a rotary vacuum evaporator to obtain the crude product. Separation was performed using a silica gel column with pure petroleum ether as the eluent for further purification. After column chromatography, a colorless oily liquid was obtained with a yield of 68%. 1 ¹H NMR and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.14(d,2H),6.90(m,4H),2.69(t,4H),1.62(m,4H),1.34(m,8H).

[0057] (5) Preparation of flexible segment monomer M2

[0058] In a 100 mL two-necked round-bottom flask, compound 3 (3 g, 10.79 mmol) was weighed and added to 40 mL of anhydrous tetrahydrofuran. Nitrogen gas was introduced, and the flask was placed in a cold trap at -78 °C. After cooling for 30 minutes, 2.5 M n-butyllithium solution (10.79 mL, 26.97 mmol) was added dropwise. After reacting for 2 hours, 1 M trimethyltin chloride solution (32.36 mL, 32.36 mmol) was slowly added to the reaction mixture. The flask was then moved to 25 °C and reacted for 4 hours. A small amount of deionized water was added to quench the reaction, and the mixture was slowly poured into a beaker containing 200 mL of deionized water. The mixture was extracted with petroleum ether, washed with deionized water, and this process was repeated three times. The product was then dried over anhydrous magnesium sulfate, filtered, and the petroleum ether was removed by rotary evaporation under reduced pressure to obtain the crude product. This crude product was then recrystallized three times with ethanol. The resulting product was dried in a vacuum oven to obtain a white, flaky solid with a yield of 81%. 1 ¹H NMR results indicate that the obtained compound is the target product. 1H NMR(500MHz,Chloroform-d)δ6.98(d,2H),6.73(d,2H),2.72(t,4H),1.65(m,4H),1.27(m,8H),0.89(m,18H).

[0059]

[0060] (6) Preparation of polymer P1

[0061] In a 25 mL flask, BDT-Th-2Sn (111.8 mg, 0.09 mmol), M2 (6.0 mg, 0.01 mmol), M1 (78.5 mg, 0.1 mmol), Pd2(dba)3 (3 mg), and P(o-tol) (6 mg) were dissolved in degassed toluene (5 mL). The mixture was stirred vigorously at 100 °C for 12 hours under nitrogen. After cooling to room temperature, the mixture was added dropwise to methanol. The precipitate was collected by filtration. The polymer was then washed sequentially with acetone and n-hexane in a Soxhlet extractor for 24 hours, followed by Soxhlet extraction with chloroform. The chloroform fraction was collected and concentrated by vacuum distillation, and the concentrated chloroform solution was precipitated in methanol. The final product P1 was collected by filtration and dried under vacuum at 50 °C for 12 hours to give 105.2 mg of black solid, with a yield of 68.3%. 1 ¹H NMR and elemental analysis results indicate that the obtained polymer is the target product. 1 H NMR (500MHz, Chloroform-d) δ7.81(m,14H),7.35(m,6H),6.91(m,8H),2.75(m,6H),2.40(m,2H),1.59(m,18H),1.31(m,64H),0.89(m,12H).

[0062]

[0063] Example 2: Preparation of P2 material containing thermally defunctionalized functional groups and flexible segment polymer active layer

[0064] (1) Preparation of compound 4

[0065] In a dried 100 mL three-necked round-bottom flask, 6,6'-dibromoisoindigo (1.26 g, 3 mmol) was added and dissolved in 30 mL of dichloromethane. The resulting solution was purged with argon for 20 min. Dimethylaminopurine (37 mg, 0.3 mmol) was added, and the reaction mixture was stirred at room temperature under an argon atmosphere for 30 min. Then, di-tert-butyl dicarbonate (1.44 g, 6.6 mmol) was added, and the mixture was stirred at room temperature for 24 h. The reaction mixture was filtered to obtain a faint red solid, which was washed three times with methanol. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After drying under vacuum to remove the organic solvent, 1.59 g of compound 4 red powder was given, with a yield of 85%. 1 H NMR(500MHz,Chloroform-d)δ8.28(d,2H),8.04(d,2H),7.56(d,2H),1.59(m,18H).

[0066] (2) Preparation of compound 5

[0067] In a dried 100 mL three-necked round-bottom flask, compound 4 (0.63 g, 1.02 mmol) and thiophene tert-butyl (0.95 g, 1.02 mmol) tin were added and dissolved in 30 mL of ultra-dry tetrahydrofuran. The resulting solution was purged with nitrogen for 20 min. Tris(dibenzylacetone)dipalladium(O) (3.5 mg) and tris(o-tolyl)phosphine (10 mg) were added, and the reaction mixture was bubbled with nitrogen for 20 min. The mixture was stirred at 80 °C for 4 h. The mixture was then cooled to room temperature and poured into water. The organic phase was extracted with dichloromethane, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After drying under vacuum to remove the organic solvent, 1.27 g of compound 5 brown powder was obtained, with a yield of 79%. 1 H NMR(500MHz,Chloroform-d)δ8.10(d,2H),7.84(d,2H),7.68(d,2H),7.59(d,2H),7.54(d,2H),7.17(d,2H),1.59(m,18H).

[0068] (3) Preparation of monomer M3

[0069] At room temperature, N-bromosuccinimide (NBS) (0.683 g, 3.84 mmol) was added in five portions over 2 hours to a tetrahydrofuran (60 mL) solution of compound 5 (1.0 g, 1.60 mmol). The mixture was stirred at 30 °C for 4 hours and then poured into water. The organic phase was extracted with diethyl ether, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. 1.76 g of a brown solid was given, with a yield of 92%. 1 H NMR(500MHz,Chloroform-d)δ8.10(d,1H),7.85(d,1H),7.68(d,1H),7.19(d,1H),7.09(d,1H),1.59(m,6H).

[0070]

[0071] (4) Preparation of compound 6

[0072] Thiophene (10 g, 118.85 mmol) was weighed and added to a 100 mL two-necked round-bottom flask. Nitrogen gas was introduced, followed by the addition of 30 mL of anhydrous tetrahydrofuran. The flask was placed in a cold trap at -78 °C and cooled for 30 minutes. Then, 2.5 M n-butyllithium solution (38.03 mL, 95.08 mmol) was added dropwise to the reaction flask, and the reaction was continued for another 30 minutes. The refrigeration was then turned off, and the temperature was restored to 25 °C for 2 hours. The temperature was lowered to -78 °C again, and after reacting for 30 minutes, 1,6-dibromohexane (11.60 g, 47.54 mmol) was added dropwise. After the addition was complete, the temperature was restored to 25 °C, and the reaction was continued for another 3 hours. Post-reaction treatment: A small amount of deionized water was added to quench the reaction. The reaction solution was then poured into a beaker containing 200 mL of saturated ammonium chloride aqueous solution, extracted with petroleum ether, washed with deionized water, and the extraction was repeated three times. The solution was dried over anhydrous magnesium sulfate, filtered, and the petroleum ether was removed using a rotary vacuum evaporator to obtain the crude product. Separation was performed using a silica gel column with pure petroleum ether as the eluent for further purification. After column chromatography, a colorless oily liquid was obtained with a yield of 66%. 1 ¹H NMR and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.14(d,2H),6.92(m,4H),2.69(t,4H),1.62(m,4H),1.38(m,4H).

[0073] (5) Preparation of flexible segment monomer M4

[0074] In a 100 mL two-necked round-bottom flask, compound 6 (2.7 g, 10.79 mmol) was weighed and added to 40 mL of anhydrous tetrahydrofuran. Nitrogen gas was purged, and the flask was placed in a cold trap at -78 °C. After cooling for 30 minutes, 2.5 M n-butyllithium solution (10.79 mL, 26.97 mmol) was added dropwise. After reacting for 2 hours, 1 M trimethyltin chloride solution (32.36 mL, 32.36 mmol) was slowly added to the reaction mixture. The flask was then moved to 25 °C and reacted for 4 hours. A small amount of deionized water was added to quench the reaction, and the mixture was slowly poured into a beaker containing 200 mL of deionized water. The mixture was extracted with petroleum ether, washed with deionized water, and this process was repeated three times. The product was then dried over anhydrous magnesium sulfate, filtered, and the petroleum ether was removed by rotary evaporation under reduced pressure to obtain the crude product. This crude product was then recrystallized three times with ethanol. The resulting product was dried in a vacuum oven to obtain a white, flaky solid with a yield of 79%. 1 ¹H NMR and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ6.98(d,2H),6.73(d,2H),2.72(t,4H),1.64(m,4H),1.38(m,4H),0.85(m,18H).

[0075]

[0076] (6) Preparation of polymer P2

[0077] In a 25 mL flask, BDT-FT-2Sn (79.7 mg, 0.08 mmol), M4 (11.5 mg, 0.02 mmol), M3 (78.5 mg, 0.1 mmol), Pd2(dba)3 (4 mg), and P(o-tol) (8 mg) were dissolved in degassed toluene (5 mL). The mixture was stirred vigorously at 110 °C for 12 hours under nitrogen. After cooling to room temperature, the mixture was added dropwise to methanol. The precipitate was collected by filtration. The polymer was then washed sequentially with acetone and n-hexane in a Soxhlet extractor for 24 hours, followed by Soxhlet extraction with chloroform. The chloroform fraction was collected and concentrated by vacuum distillation, and the concentrated chloroform solution was precipitated in methanol. The final product P2 was collected by filtration and dried under vacuum at 50 °C for 12 hours to give 99.3 mg of black solid, with a yield of 62.3%.

[0078]

[0079] Example 3: Preparation of P3, a polymer active layer material containing thermally defunctionalized functional groups and flexible segment polymers.

[0080] (1) Preparation of compound 7

[0081] In a dried 100 mL three-necked round-bottom flask, 0.9 g (3 mmol) of 3,6-bis(thiophen-2-yl)pyrrolo[3,4-c]pyrrolo-1,4(2H,5H)-dione was added and dissolved in 30 mL of dichloromethane. The resulting solution was purged with argon for 20 min. Dimethylaminopurine (37 mg, 0.3 mmol) was added, and the reaction mixture was stirred at room temperature under an argon atmosphere for 30 min. Then, di-tert-butyl dicarbonate (1.44 g, 6.6 mmol) was added, and the mixture was stirred at room temperature for 24 h. The reaction mixture was filtered to obtain a faint red solid, which was washed three times with methanol. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After removing the organic solvent by vacuum drying, 0.8 g of compound 7 red powder was given, with a yield of 80%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.55(d,2H),7.48(d,2H),7.18(t,2H),1.60(m,18H).

[0082] (2) Preparation of monomer M5

[0083] At room temperature, N-bromosuccinimide (NBS) (0.683 g, 3.84 mmol) was added in five portions over 2 hours to a tetrahydrofuran (60 mL) solution of compound 7 (1.0 g, 1.60 mmol). The mixture was stirred at 30 °C for 4 hours and then poured into water. The organic phase was extracted with diethyl ether, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. 1.76 g of a brown solid was given, with a yield of 92%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.59(d,2H),7.13(d,2H),1.60(m,18H).

[0084]

[0085] (3) Preparation of polymer P3

[0086] In a 25 mL flask, BDT-FT-2Sn (69.8 mg, 0.07 mmol), M4 (17.3 mg, 0.03 mmol), M5 (65.8 mg, 0.1 mmol), Pd2(dba)3 (4 mg), and P(o-tol) (8 mg) were dissolved in degassed toluene (5 mL). The mixture was stirred vigorously at 110 °C for 12 hours under nitrogen. After cooling to room temperature, the mixture was added dropwise to methanol. The precipitate was collected by filtration. The polymer was then washed sequentially with acetone and n-hexane in a Soxhlet extractor for 24 hours, followed by Soxhlet extraction with chloroform. The chloroform fraction was collected and concentrated by vacuum distillation, and the concentrated chloroform solution was precipitated in methanol. The final product P3 was collected by filtration and dried under vacuum at 50 °C for 12 hours to give 105.6 mg of black solid, with a yield of 70.7%.

[0087]

[0088] Example 4: Preparation of P4 material containing thermally defunctionalized functional groups and flexible segment polymer active layer

[0089] (1) Preparation of compound 8

[0090] 4,6-bis(2-thienyl)thiophene[3,4-C][1,2,5]thiadiazole (643 mg, 2.1 mmol), dimethyl butynedioate (313 mg, 2.2 mmol), and Ac₂O (51 mg, 0.5 mmol) were mixed and dissolved in 20 mL of benzene. The mixture was stirred under a nitrogen atmosphere and heated to 130 °C for 6 h. Then, 1-aminooctane (272 mg, 2.1 mmol) was added, and the reaction was carried out at 110 °C for 24 h. After cooling to room temperature, the solution was poured into water and extracted with ethyl acetate. The organic phase was concentrated by rotary evaporation under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography with petroleum ether:ethyl acetate = 15:1 (vol:vol) as the mobile phase, finally yielding 0.80 g of a yellow solid, with a yield of 89.1%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ8.19(s,1H),7.48(d,2H),7.41(d,2H),7.20(d,2H),3.78(t,2H),1.67(m,2H),1.30(m,10H),0.87(m,3H).

[0091] (2) Preparation of compound 9

[0092] Compound 8 (915 mg, 1.9 mmol) and zinc powder (1.2 g, 19 mmol) were completely dispersed in 50 mL of acetic acid and heated under reflux for 1.5 h. After cooling to room temperature, the solution was poured into water and extracted with ethyl acetate. The organic phase was collected, thoroughly washed with water to remove acetic acid, and immediately concentrated by rotary evaporation under reduced pressure. The product was then dissolved in 92 mL of a mixed solution (THF:water:acetic acid = 80:8:4) with NaNO2 (0.25 g, 3.6 mmol). The system was heated and stirred at 50 °C for 1 h. The product was washed with water, extracted with dichloromethane, concentrated by distillation under reduced pressure, and dried to give 0.73 g of compound 9, with a yield of 80.7%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.48(d,2H),7.34(d,2H),7.20(d,2H),3.78(t,2H),1.67(m,2H),1.30(m,10H),0.87(m,3H).

[0093] (3) Preparation of compound 10

[0094] In a dried 100 mL three-necked round-bottom flask, compound 9 (1.4 g, 3 mmol) was added and dissolved in 30 mL of dichloromethane. The resulting solution was purged with argon for 20 min. Dimethylaminopurine (37 mg, 0.3 mmol) was added, and the reaction mixture was stirred at room temperature under an argon atmosphere for 30 min. Then, di-tert-butyl dicarbonate (1.44 g, 6.6 mmol) was added, and the mixture was stirred at room temperature for 24 h. The reaction mixture was filtered to obtain a faint red solid, which was washed three times with methanol. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After drying under vacuum to remove the organic solvent, 0.8 g of compound 10, a yellow powder, was given, with a yield of 58%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product.

[0095] (4) Preparation of monomer M6

[0096] At room temperature, N-bromosuccinimide (NBS) (0.683 g, 3.84 mmol) was added in five portions over two hours to a tetrahydrofuran (60 mL) solution of compound 10 (0.9 g, 1.60 mmol). The mixture was stirred at 30 °C for 4 hours and then poured into water. The organic phase was extracted with diethyl ether, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. 1.06 g of a yellow solid was given, with a yield of 91.8%. 1H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.48(d,2H),7.27(d,2H),7.20(d,2H),3.78(t,2H),1.68(m,2H),1.24(m,10H),0.89(m,3H).

[0097]

[0098] (5) Preparation of polymer P4

[0099] In a 25 mL flask, BDT-FT-2Sn (69.8 mg, 0.07 mmol), 1,2-bis(5-trimethylstanthiophen-2-yl)ethylene (15.5 mg, 0.03 mmol), M6 (72.2 mg, 0.1 mmol), Pd2(dba)3 (4 mg), and P(o-tol) (8 mg) were dissolved in degassed chlorobenzene (5 mL). The mixture was stirred vigorously at 120 °C for 24 hours under nitrogen. After cooling to room temperature, the mixture was added dropwise to methanol. The precipitate was collected by filtration. The polymer was then washed sequentially with acetone and n-hexane in a Soxhlet extractor for 24 hours, followed by Soxhlet extraction with chloroform. The chloroform fraction was collected and concentrated by vacuum distillation, and the concentrated chloroform solution was precipitated in methanol. The final product P4 was collected by filtration and dried under vacuum at 50 °C for 12 hours to give 118.6 mg of a reddish-black solid, with a yield of 80.9%.

[0100]

[0101] Example 5: Preparation of P5, a polymer active layer material containing thermally defunctionalized functional groups and flexible segment polymers.

[0102] (1) Preparation of compound 12

[0103] In a dried 100 mL three-necked round-bottom flask, compound 11 (769 mg, 3 mmol) was added and dissolved in 30 mL of dichloromethane. The resulting solution was purged with argon for 20 min. Dimethylaminopurine (37 mg, 0.3 mmol) was added, and the reaction mixture was stirred at room temperature under an argon atmosphere for 30 min. Then, di-tert-butyl dicarbonate (1.44 g, 6.6 mmol) was added, and the mixture was stirred at room temperature for 24 h. The reaction mixture was filtered to obtain a pale yellow solid, which was washed three times with methanol. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After drying under vacuum to remove the organic solvent, 0.8 g of compound 12 yellow powder was obtained, with a yield of 58%. 1 H NMR, 13CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 HNMR(500MHz,Chloroform-d)δ8.58(s,2H),8.17(d,3H),8.10(m,2H),7.80(d,2H),7.45(m,2H),7.33(d,2H),7.30(m,2H),1.61(m,18H).

[0104] (2) Preparation of monomer M7

[0105] In a 100 mL two-necked round-bottom flask, compound 12 (4.92 g, 10.79 mmol) was weighed and added to 40 mL of anhydrous tetrahydrofuran. Nitrogen gas was introduced, and the flask was placed in a cold trap at -78 °C. After cooling for 30 minutes, 2.5 M n-butyllithium solution (8.80 mL, 22.00 mmol) was added dropwise. After reacting for 2 hours, 1 M trimethyltin chloride solution (26.40 mL, 26.40 mmol) was slowly added to the reaction mixture. The flask was then moved to 25 °C and reacted for 4 hours. A small amount of deionized water was added to quench the reaction, and the mixture was slowly poured into a beaker containing 200 mL of deionized water. The mixture was extracted with petroleum ether, washed with deionized water, and this process was repeated three times. The product was then dried over anhydrous magnesium sulfate, filtered, and the petroleum ether was removed by rotary evaporation under reduced pressure to obtain a crude product. This crude product was then recrystallized three times with ethanol. The resulting product was dried in a vacuum oven to obtain a yellow solid with a yield of 69%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ8.81(s,2H),8.03(dd,2H),7.59(d,2H),7.19(d,2H),0.39(t,18H).

[0106]

[0107] (3) Preparation of compound 14

[0108] In a dried 100 mL three-necked round-bottom flask, dipropylamine (304 mg, 3 mmol) was added and dissolved in 25 mL of dichloromethane. The resulting solution was purged with argon for 20 min. Dimethylaminopurine (37 mg, 0.3 mmol) was added, and the reaction mixture was stirred at room temperature under an argon atmosphere for 30 min. Then, di-tert-butyl dicarbonate (1.44 g, 6.6 mmol) was added, and the mixture was stirred at room temperature for 24 h. The reaction mixture was filtered to obtain a white solid, which was washed three times with methanol. The crude product was purified by rapid chromatography using dichloromethane as the eluent. After drying under vacuum to remove the organic solvent, 0.8 g of a yellow powder was obtained, with a yield of 58%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 HNMR(500MHz,Chloroform-d)δ3.20(t,4H),1.58(t,4H),1.45(m,18H),0.88(t,6H).

[0109] (4) Preparation of compound 15

[0110] At room temperature, N-bromosuccinimide (NBS) (0.683 g, 3.84 mmol) was added in five portions over 2 hours to a 20 mL solution of compound 14 (322.0 mg, 1.60 mmol) in tetrahydrofuran. The mixture was stirred at 30 °C for 4 hours and then poured into water. The organic phase was extracted with diethyl ether, washed with water, and dried over anhydrous magnesium sulfate. The crude product was purified by rapid chromatography using dichloromethane as the eluent. The product was given as a yellow solid in 90.5% yield. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR (500MHz, Chloroform-d) δ3.46 (t, J = 5.1 Hz, 4H), 3.28 (d, J = 11.2 Hz, 4H), 1.98 (m, 4H), 1.45 (m, 18H).

[0111] (5) Preparation of compound 16

[0112] Compound 15 (754.1 mg, 2.1 mmol), 2-tributyltinylthiophene (3.02 g, 8.4 mmol), and Pd(PPh3)2Cl2 (140 mg, 0.2 mmol) were dissolved in a mixture of toluene and DMF (20 mL + 4 mL). The mixture was stirred under a nitrogen atmosphere and heated to reflux for 20 h. After cooling to room temperature, the solution was poured into water and extracted with ethyl acetate. The organic phase was concentrated by rotary evaporation under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography using petroleum ether:ethyl acetate = 15:1 (vol:vol) as the mobile phase, ultimately yielding a yellow solid in 82.7% yield. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ7.15(d,2H),6.93(m,4H),3.24(t,4H),2.59(t,4H),1.88(t,4H),1.45(m,18H).

[0113] (6) Preparation of monomer M8

[0114] In a 100 mL two-necked round-bottom flask, compound 16 (3.94 g, 10.79 mmol) was weighed and added to 30 mL of anhydrous tetrahydrofuran. Nitrogen gas was purged, and the flask was placed in a cold trap at -78 °C. After cooling for 30 minutes, 2.5 M n-butyllithium solution (8.80 mL, 22.00 mmol) was added dropwise. After reacting for 2 hours, 1 M trimethyltin chloride solution (26.40 mL, 26.40 mmol) was slowly added to the reaction mixture. The flask was then moved to 25 °C and reacted for 4 hours. A small amount of deionized water was added to quench the reaction, and the mixture was slowly poured into a beaker containing 200 mL of deionized water. The mixture was extracted with petroleum ether, washed with deionized water, and this process was repeated three times. The product was then dried over anhydrous magnesium sulfate, filtered, and the petroleum ether was removed by rotary evaporation under reduced pressure to obtain a crude product. This crude product was then recrystallized three times with ethanol. The resulting product was dried in a vacuum oven to obtain a yellow solid with a yield of 42%. 1 H NMR, 13 CNMR, MS and elemental analysis results indicate that the obtained compound is the target product. 1 H NMR(500MHz,Chloroform-d)δ6.98(d,2H),6.73(d,2H),3.24(t,4H),2.62(t,4H),1.90(t,4H),0.39(t,18H).

[0115]

[0116] (7) Preparation of polymer P5

[0117] In a 25 mL flask, M6 (72.3 mg, 0.1 mmol), M7 (62.6 mg, 0.08 mmol), M8 (50.8 mg, 0.02 mmol), Pd2(dba)3 (4 mg), and P(o-tol) (8 mg) were dissolved in degassed chlorobenzene (5 mL). The mixture was stirred vigorously at 120 °C for 24 hours under nitrogen. After cooling to room temperature, the mixture was added dropwise to methanol. The precipitate was collected by filtration. The polymer was then washed sequentially with acetone and n-hexane in a Soxhlet extractor for 24 hours, followed by Soxhlet extraction with chloroform. The chloroform fraction was collected and concentrated by vacuum distillation, and the concentrated chloroform solution was precipitated in methanol. The final product P5 was collected by filtration and dried under vacuum at 50 °C for 12 hours to give 105.0 mg of black solid, with a yield of 75.6%.

[0118]

[0119] Example 6: Precise Control of Glass Transition Temperature of Polymer Active Layer Material

[0120] Taking the P4 series polymer containing thermally defunctionalized functional groups and flexible segment polymers in Example 4 as an example, its general formula is shown below.

[0121]

[0122] The specific steps for implementing the regulation are as follows:

[0123] (1) Polymer P4 was prepared under the same reaction conditions, wherein BDT-FT-2Sn (0.1-x mmol), 1,2-bis(5-trimethylstanthiophen-2-yl)ethylene (x mmol), M6 (72.0 mg, 0.1 mmol), and the remaining conditions were the same as in Example 4.

[0124] (2) Starting from 0, the ratio x was increased to 0.1 and then to 0.3 to prepare representative polymers containing heat-removed functional groups and flexible segments with flexible segment contents of 0%, 10%, and 30%, respectively, which were named P4-0, P4-0.1 and P4.

[0125] (3) Scanning differential calorimetry (SDC) was used to test the polymer material. When x = 0, 0.1, and 0.3, the glass transition temperature of the polymer decreased significantly from unmeasurable (thermal desorption occurs before reaching the glass transition temperature), 160℃, and 149℃, respectively. It can be seen that the glass transition temperature of the semiconductor polymer can be precisely controlled by adjusting the proportion of flexible segments. When x = 0.3, the glass transition temperature of polymer P4 is 149℃, which is significantly lower than the removal temperature of the thermally desorbed group (200℃), and can meet the requirement of thermal desorption above the glass transition temperature, thus obtaining a better thermal desorption device effect.

[0126] With x = 0.1, 0.2, or 0.3, and n such that the molecular weight distribution is 25 ± 5 kDa, the characteristic temperatures and solubility of the polymer active layer materials in Examples 1-4 are shown in Table 1 below, where T f and T a The device processing temperature is set manually, with only Tg being the temperature obtained through testing.

[0127] Table 1. Characteristic temperatures and solubility of polymer active layer materials in Examples 1-4

[0128]

[0129] Wherein, 2-MeTHF, CF, and CB are 2-methyltetrahydrofuran, chloroform, and chlorobenzene, respectively. "+" indicates that the polymer can be completely dissolved in the solvent at 10 mg / mL; "++" indicates that the polymer can be completely dissolved in the solvent at 25 mg / mL.

[0130] Example 7: Preparation of the solvent-resistant layer of polymer active layer material P4

[0131] Taking the material in Example 4 above as an example, the chemical reaction equation for thermal removal is as follows:

[0132]

[0133] Comparison of the polymer's 1H NMR spectrum before thermal removal ( 1 ¹H NMR (500MHz, Chloroform-d) δ 8.04 (m, 2H), 7.78 (m, 2H), 7.20 (m, 2H), 6.96 (m, 2H), 3.78 (m, 2H), 2.71 (m, 4H), 1.60 (m, 9H), 1.30 (m, 53H).) and the NMR of the polymer after thermal removal ( 1 ¹H NMR (500MHz, Chloroform-d) δ 8.06 (m, 3H), 7.75 (m, 2H), 7.20 (m, 2H), 7.04 (m, 2H), 3.78 (m, 2H), 2.73 (m, 4H), 1.27 (m, 53H)., confirming that the tert-butoxy carbonyl group disappeared after removal, while the other functional groups showed no significant changes, demonstrating precise removal characteristics.

[0134] The solvent-resistant layer is prepared by using the materials in Example 4 above. The specific steps are as follows:

[0135] (1) Cleaning of conductive glass ITO substrate: The ITO glass substrate is placed in acetone, isopropanol, cleaning solution, deionized water and isopropanol in sequence for ultrasonic cleaning to remove any residues (such as photoresist) that may remain on the surface of the ITO glass substrate and to improve the interface contact. After cleaning, it is placed in a vacuum oven to dry.

[0136] (2) Place the ITO in an oxygen plasma etching instrument and bombard it with oxygen plasma for twenty minutes to thoroughly remove any organic matter that may remain on the surface of the ITO glass substrate.

[0137] (3) A hole transport interface PEDOT:PSS of a certain thickness was spin-coated on ITO, and then heat-annealed at 100°C for 20 minutes.

[0138] (4) Cool to 25°C, dissolve the polymer donor material P4 containing flexible segments in 2-methyltetrahydrofuran solvent to prepare a solution with a concentration of 8 mg / mL, spin-coat a donor layer on the PEDOT:PSS layer, and heat and anneal at 200°C for 15 minutes on a heating stage to remove thermally desorbed groups, reduce solubility, and allow the film morphology to self-level.

[0139] (5) Solvent-resistant layer performance testing: Annealed and unannealed solvent-resistant layer films were immersed in a methyltetrahydrofuran solvent bath. After standing for 60 seconds, they were removed and the thickness of the two films and the un-immersed film was compared using a profilometer. It was found that the thickness of the annealed solvent-resistant active layer remained basically unchanged, while the thickness of the unannealed active layer decreased by more than 80%, indicating complete corrosion by the solvent. This proves that the active layer material after thermal desorption possesses solvent resistance.

[0140] Example 8: Fabrication of an organic solar cell device with a solvent-resistant layer

[0141] Organic solar cell devices were fabricated using the polymer active layer materials P4 and P4-0 from Example 4 above, and the common polymer acceptor material N2200, respectively. The device structure was: ITO / PEDOT:PSS / active layer / PFN-Br (methanol 0.5 mg / mL). -1 The structure of N2200 is as shown in Formula IV:

[0142]

[0143] The specific steps for fabricating this organic solar cell device are as follows:

[0144] (1) Cleaning of conductive glass ITO substrate: The ITO glass substrate is placed in acetone, isopropanol, cleaning solution, deionized water and isopropanol in sequence for ultrasonic cleaning to remove any residues (such as photoresist) that may remain on the surface of the ITO glass substrate and to improve the interface contact. After cleaning, it is placed in a vacuum oven to dry.

[0145] (2) Place the ITO in an oxygen plasma etching instrument and bombard it with oxygen plasma for twenty minutes to thoroughly remove any organic matter that may remain on the surface of the ITO glass substrate.

[0146] (3) A hole transport interface PEDOT:PSS of a certain thickness was spin-coated on ITO, and then heat-annealed at 100°C for 20 minutes.

[0147] (4) Cool to 25°C, dissolve the polymer active layer material P4 (x = 0.3) containing flexible segments in methyltetrahydrofuran solvent to prepare a solution with a concentration of 8 mg / mL, spin-coat a layer of photoactive donor material on the PEDOT:PSS layer, heat and anneal at 200°C for 15 minutes on a heating stage to remove thermally desorbed groups, reduce solubility, and allow the film morphology to self-level, forming a solvent-resistant donor planar transition layer of the donor photoactive material;

[0148] (5) The active layer material P4-0 from Example 6 is then mixed with N2200 at a mass ratio of 1:1, dissolved in 2-methyltetrahydrofuran, and a solution with a concentration of 6 mg / mL is prepared. The active layer is then spin-coated to form a donor-acceptor heterojunction film.

[0149] (6) In a glove box under a nitrogen atmosphere, spin-coat an electron transport material onto the active layer material. The material used is 0.5 mg / mL poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-ALT-[(9,9-di-n-octylfluorenyl-2,7-diyl)bromo(PFN-Br);

[0150] (7) Finally, the prepared device is placed in the vapor deposition chamber and Ag electrode is vapor deposited in a vacuum environment.

[0151] (8) The photoelectric conversion efficiency and current-voltage characteristic curves of polymer solar cell device P4 were tested under an AM 1.5G simulated sunlight lamp.

[0152] Prepare unannealed devices (skip the "heat annealing at 200°C for 15 minutes on a heating stage"), and follow the same preparation steps as a control group device.

[0153] The photoelectric performance of the fabricated organic solar cell devices was tested, and their current density-voltage characteristics and external quantum efficiency are shown in the attached figure. Figure 2 and 3 The test results are shown in Table 2.

[0154] Table 2 Device parameters of organic solar cells

[0155]

[0156] Table 2 shows that the organic solar cell device with a P4 donor solvent-resistant layer exhibits better photoelectric performance. The short-circuit current density is 19.3 mA / cm², the open-circuit voltage is 0.9 V, the fill factor is 71%, and the final device efficiency is 11.4%. However, the unannealed P4 donor layer is dissolved and corroded by the solvent in the donor-acceptor mixed solution, resulting in a significantly reduced short-circuit current density of 16.2 mA / cm², an open-circuit voltage of 0.9 V, a fill factor of 65%, and a final device efficiency of 10.0%. Therefore, spin-coating a thermally desorbable functionalized and flexible modified donor polymer onto the PEDOT layer can improve the performance of photovoltaic devices. Figure 4 The dark-state voltage-current density curves obtained from the tests on the fabricated organic photovoltaic device show that the device exhibits obvious diode characteristics, namely unidirectional current conduction, with the forward dark current being significantly higher than the reverse dark current. This is of great significance for improving the detector's detectivity and its ability to detect weak light.

[0157] The performance of the remaining polymer photovoltaic devices prepared using the same method (using polymers containing flexible segments (P1, P2, P3, P5) to prepare solvent-resistant planar donor layers, and using the corresponding x=0 polymers mixed with acceptors to prepare bulk heterojunctions) is shown in Table 3.

[0158] Table 3 Device parameters of organic solar cells

[0159]

[0160] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A class of polymeric photoactive materials containing thermally desorbable functional groups and flexible segments, characterized in that... The structure is shown in Equation I below: , Formula I In Equation I, the structures of unit D, unit A, and the flexible chain segment satisfy Equation I, as shown in Equation P4 below: , In Formula I, x = 5%~30%, n = 2~300; The glass transition temperature of the polymer photoactive material is lower than its thermal desorption annealing temperature.

2. A method for preparing a polymer photoactive material containing thermally deactivated functional groups and flexible segments according to claim 1, characterized in that... Includes the following steps: In an inert gas atmosphere and an organic solvent, monomers containing flexible segment units, monomers containing D units, and monomers containing A units are mixed and then polymerized under the catalysis of a catalyst. After purification, the polymer active layer material containing thermally deactivated functional groups and flexible segments is obtained.

3. The method for preparing the polymer photoactive material containing thermally deactivated functional groups and flexible segments according to claim 2, characterized in that: The organic solvent is one of chlorobenzene, dichlorobenzene, toluene, and xylene; the catalyst is a palladium catalyst; the sum of the amounts of the reactive functional groups of the monomer containing flexible segment units and the monomer containing electron donor units is equal to the amount of the reactive functional groups of the monomer containing electron acceptor units. The polymerization reaction is carried out at a temperature of 110-140°C for 40-60 h.

4. The application of the polymer photoactive material containing thermally desorbable functional groups and flexible segments as described in claim 1 in organic photovoltaic devices.

5. The application of the polymer photoactive material containing thermally desorbable functional groups and flexible segments as described in claim 1 in organic solar cells, organic photodetectors, organic field-effect transistors, and organic light-emitting diodes.

6. A solution processing method for an organic photovoltaic device comprising the polymer photoactive material containing thermally desorbable functional groups and flexible segments as described in claim 1, characterized in that... Includes the following steps: A polymeric photoactive material containing thermally desorbable functional groups and flexible segments is dissolved in an organic solvent to obtain a solution. A flat film is obtained through solution processing. The film is then heat-treated at a thermal desorption annealing temperature to remove the thermally desorbable groups, thereby losing its strong solubility in organic solvents and becoming a solvent-resistant layer. Then, spin-coat the mixed solution of the polymer photoactive material with P4 structure when x is 0 in claim 1 and the acceptor onto the solvent-resistant layer.

7. The solution processing method for an organic photovoltaic device comprising the polymer photoactive material containing thermally desorbable functional groups and flexible segments as described in claim 1, as described in claim 6, is characterized in that: The organic solvent is at least one of 2-methyltetrahydrofuran, chloroform, and chlorobenzene; The heat treatment refers to annealing at 150-230℃ for 10-60 minutes.

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