A polythiophene-based active layer, and a method for preparing and using the same

Abstract

The application provides a polythiophene-based active layer and a preparation method and application thereof, and the method comprises the following steps: S1: adsorbing D-pi-A type organic dye molecules on the surface of a semiconductor photoanode to obtain a working electrode; S2: under light irradiation, a first cyclic voltammetry scan is applied to the working electrode to perform electrochemical polymerization of N-tert-butoxycarbonyl-3-aminophenylthiophene, so as to obtain a first working electrode; wherein the scanning low potential is-0.7V to-1.1V, and the scanning high potential is 1.4V to 1.8V; S3: under light irradiation, a second cyclic voltammetry scan is applied to the first working electrode to perform electrochemical polymerization of 3,4-(2,2-dimethylpropylene dioxy) thiophene, wherein the scanning low potential is-0.7V to-1.1V, and the scanning high potential is 1.2V to 1.5V. The polythiophene-based active layer and the preparation method thereof are simple in process and can be widely applied in the field of organic solar cells.

Description

Technical Field

[0001] This application relates to the field of conductive polymer technology, the field of organic solar cells, and in particular to a polythiophene-based active layer, its preparation method and application. Background Technology

[0002] Organic solar cells, due to their advantages such as light weight, flexible fabrication, and wide availability of raw materials, represent a significant development direction for next-generation solar cells. The active layer, as the core structural layer of an organic solar cell, directly determines the device's photoelectric conversion efficiency. Polythiophene conjugated polymers are widely used as active layer materials due to their low cost, good stability, and ease of structural modification. Conjugated block copolymers possess eutectic and microphase separation properties, enabling the formation of donor-acceptor structures and demonstrating promising applications in single-component organic solar cells. Compared to bulk heterojunction systems, single-component conjugated block copolymer films exhibit both intermolecular and intramolecular charge transfer, which is beneficial for improving charge migration efficiency and suppressing photogenerated electron-hole recombination. Furthermore, the single-component nature avoids the self-aggregation problem of multiphase systems under optical, thermal, and mechanical stress.

[0003] Existing conjugated block copolymers are typically prepared via polycondensation, coupling, or chemical oxidation, requiring metal catalysts, involving complex reaction steps, and the incomplete removal of metal catalyst residues, which may affect the photoelectric properties and stability of the active layer. Electrochemical polymerization can directly deposit polymer films on conductive substrates, but requires high potentials (typically >2.0V), which can easily lead to polymer peroxidation. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a polythiophene-based active layer that exhibits good photoelectric conversion efficiency when applied in organic solar cells.

[0005] Specifically, the first aspect of this application provides a method for preparing a polythiophene-based active layer, comprising the following steps: S1: D-π-A type organic dye molecules are adsorbed onto the surface of a semiconductor photoanode to obtain a working electrode; S2: Under illumination, a first cyclic voltammetric scan is applied to the working electrode to perform electrochemical polymerization of N-tert-butoxycarbonyl-3-aminothiophene to obtain the first working electrode; wherein the scanning low potential is -0.7V to -1.1V and the scanning high potential is 1.4V to 1.8V. S3: Under illumination, a second cyclic voltammetric scan is applied to the first working electrode to perform electrochemical polymerization of 3,4-(2,2-dimethylpropenedioxy)thiophene, wherein the low scanning potential is -0.7V to -1.1V and the high scanning potential is 1.2V to 1.5V.

[0006] Optionally, in step S1, the D-π-A type organic dye molecule is selected from at least one of 3-{6-[4-{bis[2',4'-di(hexyloxy)biphenyl-4-yl]amino}phenyl]-4,4-dihexyl-cyclopentadithiophen-2-yl}-2-cyanoacrylate and 3-{5-[N,N-bis(4-diphenylamino)phenyl]thiopheno[3,2-b]thiophen-2-yl}-2-cyanoacrylate.

[0007] Optionally, in steps S2 and S3, the light intensity is 80 mW / cm². 2 ~120mW / cm 2 .

[0008] Optionally, in both steps S2 and S3, the electrochemical polymerization is carried out in an electrolyte solution.

[0009] Optionally, in both steps S2 and S3, the electrochemical polymerization uses a three-electrode system.

[0010] Optionally, in steps S2 and S3, the electrolyte in the electrolyte solution is individually tetramethylammonium tetrafluoroborate.

[0011] Optionally, in steps S2 and S3, the solvent in the electrolyte solution is propylene carbonate, each independently.

[0012] Optionally, in step S2, the molar ratio of N-tert-butoxycarbonyl-3-aminothiophene to the electrolyte solution is 1:1.5 to 2.5.

[0013] Optionally, in step S3, the molar ratio of 3,4-(2,2-dimethylpropenedioxy)thiophene to the electrolyte solution is 1:1.5 to 2.5.

[0014] Optionally, in step S2, the first cyclic voltammetric scan rate is 50mV / s to 100mV / s.

[0015] Optionally, in step S3, the second cyclic voltammetric scan rate is 20mV / s to 100mV / s.

[0016] Optionally, in steps S2 and S3, the scanning cycle of the first cyclic voltammetric scan and the second cyclic voltammetric scan is 1 to 50 times.

[0017] Optionally, step S3 may be followed by a deprotection process and an annealing process performed sequentially.

[0018] Optionally, the deprotection treatment involves immersing the product obtained in step S3 in an acidic solution.

[0019] Optionally, the annealing process is performed under inert gas protection.

[0020] Optionally, the annealing temperature is 100℃~180℃.

[0021] Optionally, the heating rate of the annealing treatment is 2℃ / min to 10℃ / min.

[0022] Optionally, the holding time for the annealing treatment is 15 min to 60 min.

[0023] Optionally, the acidic solution is a mixture of trifluoroacetic acid and dichloromethane.

[0024] The second aspect of this application provides a polythiophene-based active layer, which is prepared by the method described above for preparing a polythiophene-based active layer.

[0025] A third aspect of this application provides an application of the aforementioned polythiophene-based active layer in the field of organic solar cells.

[0026] Compared with the prior art, the present invention has the following beneficial effects: This invention uses N-tert-butoxycarbonyl-3-aminothiophene and 3,4-(2,2-dimethylpropenedioxy)thiophene as comonomers. Guided by dye anchoring sites, stepwise cyclic voltammetry scanning is performed under illumination to shift the driving force of the polymerization reaction from "applied voltage" to "photogenerated holes," achieving ordered polymerization of the monomers at a relatively low potential (1.2V~1.8V) to obtain a polythiophene-based active layer. Organic solar cells using the material prepared in this invention as the active layer achieve a photoelectric conversion efficiency of over 6%.

[0027] The polythiophene-based active layer and its preparation method provided by this invention are simple in process, do not require metal catalysts, and can be widely used in the field of organic solar cells. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following description and illustration are provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0029] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0030] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0031] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0032] On one hand, embodiments of this application provide a method for preparing a polythiophene-based active layer, comprising the following steps: S1: D-π-A type organic dye molecules are adsorbed onto the surface of a semiconductor photoanode to obtain a working electrode; S2: Under illumination, a first cyclic voltammetric scan is applied to the working electrode to perform electrochemical polymerization of N-tert-butoxycarbonyl-3-aminothiophene to obtain the first working electrode; wherein the scanning low potential is -0.7V to -1.1V and the scanning high potential is 1.4V to 1.8V. S3: Under illumination, a second cyclic voltammetric scan is applied to the first working electrode to perform electrochemical polymerization of 3,4-(2,2-dimethylpropenedioxy)thiophene, wherein the low scanning potential is -0.7V to -1.1V and the high scanning potential is 1.2V to 1.5V.

[0033] This application utilizes the chemical adsorption of dye molecules onto the surface of a photoanode to form a monolayer. This monolayer serves as a light absorption layer, broadening the spectral response range, and also provides a template for subsequent electrochemical polymerization, allowing the polymer to grow near the dye molecules.

[0034] Photogenerated holes are created by exciting dye molecules under light. These holes migrate to the dye / electrolyte interface and oxidize the thiophene monomer, initiating polymerization. A controlled, repeated oxidation-reduction process is achieved through cyclic voltammetry, allowing for gradual polymer growth. N-tert-butoxycarbonyl-3-aminothiophene, as the polymerization monomer, maintains its Boc protecting group stability during polymerization, preventing side reactions of the amino group during electrochemical polymerization.

[0035] By controlling the polymerization potential of the 3,4-(2,2-dimethylpropenedioxy)thiophene monomer to be slightly lower than that of the monomer in step S2, the second monomer can be polymerized on the previous polymer chain segment.

[0036] The segments formed by the polymerization of N-tert-butoxycarbonyl-3-aminothiophene and 3,4-(2,2-dimethylpropenedioxy)thiophene have different main chain structures and spatial configurations, which are beneficial to promoting the separation of photogenerated charges and their migration to the electrode.

[0037] In some embodiments of this application, in step S1, the D-π-A type organic dye molecule is selected from at least one of 3-{6-[4-{bis[2',4'-di(hexyloxy)biphenyl-4-yl]amino}phenyl]-4,4-dihexyl-cyclopentadithiophen-2-yl}-2-cyanoacrylate and 3-{5-[N,N-bis(4-diphenylamino)phenyl]thiopheno[3,2-b]thiophen-2-yl}-2-cyanoacrylate.

[0038] The triphenylamine derivative of 3-{6-[4-{bis[2',4'-di(hexyloxy)biphenyl-4-yl]amino}phenyl]-4,4-dihexyl-cyclopentadithiophen-2-yl}-2-cyanoacrylic acid, with cyclopentadithiophene as a π-bridge and cyanoacrylic acid as an acceptor, exhibits a broad absorption spectrum.

[0039] Using a triphenylamine derivative of 3-{5-[N,N-bis(4-diphenylamino)phenyl]thieno[3,2-b]thieno-2-yl}-2-cyanoacrylic acid as a donor, thieno[3,2-b]thieno-2-yl as a π-bridge, and cyanoacrylic acid as an acceptor, the thieno[3,2-b]thieno-2-yl π-bridge exhibits better planarity.

[0040] In some embodiments of this application, the light intensity of the illumination in steps S2 and S3 is 80 mW / cm². 2 ~120mW / cm 2 .

[0041] By controlling the light intensity to 80mW / cm² 2 ~120mW / cm 2 It is equivalent to the intensity of one sun, which can stably generate a sufficient concentration of photogenerated holes and maintain a controllable aggregation rate.

[0042] In some embodiments of this application, in steps S2 and S3, the electrochemical polymerization is carried out in an electrolyte solution.

[0043] In some embodiments of this application, the electrochemical polymerization in steps S2 and S3 uses a three-electrode system.

[0044] In some embodiments of this application, in steps S2 and S3, the electrolyte in the electrolyte solution is individually tetramethylammonium tetrafluoroborate.

[0045] In some embodiments of this application, in steps S2 and S3, the solvent in the electrolyte solution is propylene carbonate.

[0046] In some embodiments of this application, in step S2, the molar ratio of N-tert-butoxycarbonyl-3-aminothiophene to the electrolyte solution is 1:1.5 to 2.5.

[0047] In some embodiments of this application, in step S3, the molar ratio of 3,4-(2,2-dimethylpropenedioxy)thiophene to the electrolyte solution is 1:1.5 to 2.5.

[0048] By controlling the molar ratio of monomer to electrolyte to be 1:1.5 to 2.5, the electrolyte can effectively support charge transport and ion migration in solution.

[0049] In some embodiments of this application, in step S2, the first cyclic voltammetric scan rate is 50mV / s to 100mV / s.

[0050] The nucleation density and growth rate of polymer chain segments are controlled by controlling the voltammetric scan rate of the first cycle.

[0051] In some embodiments of this application, in step S3, the second cyclic voltammetric scan rate is 20mV / s to 100mV / s.

[0052] Since the surface of the first working electrode is covered with the first polymer chain segment, the monomer can be fully diffused and the polymerization rate can be controlled by controlling the second cyclic voltammetric scan rate.

[0053] In some embodiments of this application, in steps S2 and S3, the scanning cycle of the first cyclic voltammetric scan and the second cyclic voltammetric scan is 1 to 50 times.

[0054] The thickness of the polymer can be adjusted as needed by controlling the scan period of the cyclic voltammetry.

[0055] In some embodiments of this application, step S3 is followed by a deprotection process and an annealing process performed sequentially.

[0056] In some embodiments of this application, the deprotection treatment involves immersing the product obtained in step S3 in an acidic solution.

[0057] Through deprotection treatment, the Boc protecting group undergoes hydrolytic cleavage under the action of acid, removing the tert-butyloxycarbonyl group and re-exposing the amino functional group.

[0058] In some embodiments of this application, the annealing process is performed under inert gas protection.

[0059] In some embodiments of this application, the annealing temperature is 100°C to 180°C.

[0060] In some embodiments of this application, the heating rate of the annealing treatment is 2°C / min to 10°C / min.

[0061] In some embodiments of this application, the holding time for the annealing treatment is 15 min to 60 min.

[0062] Annealing provides polymer chains with sufficient energy for conformational adjustment and chain rearrangement, transforming the molecular chains from a disordered state to an ordered arrangement, which facilitates the hopping transport of charge carriers between chains. By controlling the annealing temperature, heating rate, and holding time, the polymer chains gain sufficient mobility to achieve ordered arrangement, avoiding thermal decomposition of the polymer due to excessively high temperatures or holding times.

[0063] In some embodiments of this application, the acidic solution is a mixed solution of trifluoroacetic acid and dichloromethane.

[0064] On the other hand, embodiments of this application provide a polythiophene-based active layer, which is prepared using the polythiophene-based active layer preparation method described above.

[0065] In the polythiophene-based active layer provided in this application, the dye molecules provide light absorption and photocharge generation functions. The first polymer segment contains amino substituents, and the first polymer segment and the second polymer segment are connected in sequence. Due to the different monomer structures, the two have different main chain structures and spatial configurations.

[0066] On the other hand, embodiments of this application provide an application of the polythiophene-based active layer described above in the field of organic solar cells.

[0067] In the polythiophene-based active layer provided in this application, the first polymer segment and the second polymer segment cover the surface of the dye molecules, which can reduce the direct contact between the dye and the electrolyte; at the same time, the different main chain structures of the first polymer segment and the second polymer segment are beneficial to the separation of photogenerated charges and their transport to the electrode. This active layer structure is applicable to the field of organic solar cells, especially dye-sensitized solar cells and organic / inorganic hybrid solar cells.

[0068] Example The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0069] In the embodiments and comparative examples of the present invention: The TiO2 / FTO photoanode used (0.031cm) 2 The preparation method is as follows: Deionized water and 36% concentrated hydrochloric acid are mixed at a volume ratio of 1:1, and TiCl4 (the volume ratio of TiCl4 to deionized water is 1:30) is added and mixed evenly; FTO conductive glass is placed in the above solution and reacted at 150℃ for 6 hours. After the reaction is completed, it is naturally cooled to 25℃, removed and washed. Then, the temperature is increased to 450℃ at 5℃ / min, held for 60 minutes, and naturally cooled to 25℃ to obtain the final product.

[0070] The dye used is 3-{6-[4-{bis[2',4'-di(hexyloxy)biphenyl-4-yl]amino}phenyl]-4,4-dihexyl-cyclopentadithiophen-2-yl}-2-cyanoacrylate, abbreviated as Y123 dye, CAS: 1312465-92-1; The N-tert-butoxycarbonyl-3-aminothiophene used is abbreviated as N-Boc-3-aminothiophene, CAS: 19228-91-2; The 3,4-(2,2-dimethylpropenedioxy)thiophene used is abbreviated as ProDOT(Me)2, CAS: 255901-50-9.

[0071] Example 1 The method for preparing the polythiophene-based active layer in this embodiment includes the following steps: S1: The TiO2 / FTO photoanode was immersed in an ethanol solution of Y123 dye at a concentration of 0.37 mg / mL for 12 hours in the dark. After removal and cleaning, the working electrode was obtained.

[0072] S2: Place the working electrode, platinum electrode, and Ag / AgCl (saturated KCl) electrode in the first electrolyte solution at 100 mW / cm². 2 Under illumination, a first cyclic voltammetric scan was applied to the working electrode with the following parameters: low potential -0.9V, high potential 1.6V, scan rate 75mV / s, and 10 cycles. After removal, the electrode was washed and dried to obtain the first working electrode.

[0073] The electrolyte in the first electrolyte solution is tetramethylammonium tetrafluoroborate (TMABF4), the solvent is propylene carbonate, the concentration of N-Boc-3-aminothiophene is 50 mmol / L, and the concentration of TMABF4 is 100 mmol / L.

[0074] S3: Transfer the first working electrode, platinum electrode, and Ag / AgCl (saturated KCl) electrode to the second electrolyte, at 100 mW / cm². 2 Under illumination, a second cyclic voltammetric scan was applied to the first working electrode, with the following parameters: low potential -0.9V, high potential 1.3V, scan rate 75mV / s, and 10 cycles. The electrode was then removed, washed, and dried.

[0075] The second electrolyte is composed of TMABF4 as the electrolyte and propylene carbonate as the solvent. The concentration of ProDOT(Me)2 is 50 mmol / L and the concentration of TMABF4 is 100 mmol / L.

[0076] S4: Immerse the working electrode treated in step S3 in trifluoroacetic acid / dichloromethane (volume ratio 1:1) for 3 hours, then remove, wash, and dry. Under inert gas protection, heat to 150°C at 5°C / min, hold for 30 minutes, and then cool naturally to 25°C to obtain the polythiophene-based active layer electrode.

[0077] Example 2 The method for preparing the polythiophene-based active layer provided in this embodiment differs from that in Example 1 in that: In step S2, the concentration of N-Boc-3-aminothiophene in the first electrolyte is 50 mmol / L, and the concentration of TMABF4 is 75 mmol / L. In step S3, the concentration of ProDOT(Me)2 in the second electrolyte is 50 mmol / L, and the concentration of TMABF4 is 75 mmol / L.

[0078] Example 3 The method for preparing the polythiophene-based active layer provided in this embodiment differs from that in Example 1 in that: In step S2, the concentration of N-Boc-3-aminothiophene in the first electrolyte is 50 mmol / L, and the concentration of TMABF4 is 125 mmol / L. In step S3, the concentration of ProDOT(Me)2 in the second electrolyte is 50 mmol / L, and the concentration of TMABF4 is 125 mmol / L.

[0079] Example 4 The method for preparing the polythiophene-based active layer provided in this embodiment differs from that in Example 1 in that: Step S4 is not performed, that is, the deprotection process and annealing process are not performed.

[0080] Comparative Example 1 The method for preparing the polythiophene-based active layer provided in this comparative example differs from that in Example 1 in that: Steps S3 and S4 are not performed, that is, only the first working electrode is prepared.

[0081] Comparative Example 2 The method for preparing the polythiophene-based active layer provided in this comparative example differs from that in Example 1 in that: In step S2, N-Boc-3-aminothiophene is replaced with ProDOT(Me)2. The concentration of ProDOT(Me)2 in the first electrolyte is 50 mmol / L, the concentration of TMABF4 is 100 mmol / L, and the high potential is 1.3V.

[0082] Comparative Example 3 The method for preparing the polythiophene-based active layer provided in this comparative example includes the following steps: S1: Using a TiO2 / FTO photoanode as the working electrode, the working electrode, platinum electrode, and Ag / AgCl (saturated KCl) electrode were placed in the first electrolyte. A first cyclic voltammetric scan was applied to the working electrode with the following parameters: low potential -0.9V, high potential 1.6V, scan rate 75mV / s, and 10 cycles. After removal, the electrode was washed and dried to obtain the first working electrode.

[0083] The electrolyte in the first electrolyte solution is TMABF4, the solvent is propylene carbonate, the concentration of N-Boc-3-aminothiophene is 50 mmol / L, and the concentration of TMABF4 is 100 mmol / L.

[0084] S3: Transfer the first working electrode, platinum electrode, and Ag / AgCl (saturated KCl) electrode to the second electrolyte. Apply a second cyclic voltammetric scan to the first working electrode, setting the parameters as follows: low potential -0.9V, high potential 1.6V, scan rate 75mV / s, 10 cycles. After removal, wash and dry.

[0085] The second electrolyte is TMABF4 as the electrolyte and propylene carbonate as the solvent. The concentration of N-Boc-3-aminothiophene is 50 mmol / L and the concentration of TMABF4 is 100 mmol / L.

[0086] S4: Immerse the working electrode treated in step S3 in trifluoroacetic acid / dichloromethane (volume ratio 1:1) for 3 hours, then remove, wash, and dry. Under inert gas protection, heat to 150°C at 5°C / min, hold for 30 minutes, and then cool naturally to 25°C to obtain a polythiophene-based active layer electrode.

[0087] A 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD, CAS: 207739-72-8) hole transport layer was spin-coated onto the polythiophene-based active layer electrodes prepared in Examples 1-4 and Comparative Examples 1-3, followed by the deposition of silver electrodes, and the resulting organic solar cells were assembled. A 500W xenon lamp equipped with an AM1.5 filter was used as a simulated solar source, and the light output was 100mW / cm². 2 The photovoltaic performance of the obtained organic solar cells was tested under light intensity and 25°C.

[0088] The evaluation results of each performance aspect are shown in Table 1.

[0089] Table 1. Performance test results of organic solar cells using the materials prepared in Examples 1-4 and Comparative Examples 1-3 as the active layer.

[0090] As can be seen from the test data of Examples 1-4 in Table 1, the organic solar cells assembled with the polythiophene-based active layer prepared in this invention exhibit good photovoltaic performance, with a short-circuit current range of 11.59 mA / cm². 2 ~13.28mA / cm 2 The open-circuit voltage ranges from 0.79V to 0.86V, the fill factor ranges from 64.75% to 71.51%, and the photoelectric conversion efficiency ranges from 6.09% to 7.75%.

[0091] Compared to Example 1, Comparative Example 1 may have experienced a significant performance degradation due to the lack of a low bandgap block in ProDOT(Me)2, a narrow light absorption range, and a lack of synergistic effects between different main chain structures.

[0092] Compared with Example 1, the photoelectric conversion efficiency of Comparative Example 2 is only 1.09%, which may be because both blocks are composed of ProDOT(Me)2, with the same main chain structure and lack of energy level differences between different main chain structures, which is not conducive to the effective separation of photogenerated charges.

[0093] Compared with Example 1, the photoelectric conversion efficiency of Comparative Example 3 was only 1.28%, which may be because both blocks are composed of N-Boc-3-aminothiophene, and the lack of spatial constraint of dye molecules and light assistance leads to random growth of polymer chains, which is not conducive to the formation of ordered chain segment arrangement and increases charge recombination.

[0094] The polythiophene-based active layer and its preparation method provided by this invention are simple in process, do not require metal catalysts, and can be widely used in the field of organic solar cells.

[0095] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a polythiophene-based active layer, characterized in that, Includes the following steps: S1: D-π-A type organic dye molecules are adsorbed onto the surface of a semiconductor photoanode to obtain a working electrode; S2: Under illumination, a first cyclic voltammetric scan is applied to the working electrode to perform electrochemical polymerization of N-tert-butoxycarbonyl-3-aminothiophene to obtain the first working electrode; wherein the scanning low potential is -0.7V to -1.1V and the scanning high potential is 1.4V to 1.8V. S3: Under illumination, a second cyclic voltammetric scan is applied to the first working electrode to perform electrochemical polymerization of 3,4-(2,2-dimethylpropenedioxy)thiophene, wherein the low scanning potential is -0.7V to -1.1V and the high scanning potential is 1.2V to 1.5V.

2. The method for preparing the polythiophene-based active layer according to claim 1, characterized in that, In step S1, the D-π-A type organic dye molecule is selected from at least one of 3-{6-[4-{bis[2',4'-di(hexyloxy)biphenyl-4-yl]amino}phenyl]-4,4-dihexyl-cyclopentadithiophen-2-yl}-2-cyanoacrylate and 3-{5-[N,N-bis(4-diphenylamino)phenyl]thiopheno[3,2-b]thiophen-2-yl}-2-cyanoacrylate.

3. The method for preparing the polythiophene-based active layer according to claim 1, characterized in that, In both steps S2 and S3, the light intensity is 80 mW / cm². 2 ~120mW / cm 2 ; And / or, in both steps S2 and S3, the electrochemical polymerization is carried out in an electrolyte solution; And / or, in both steps S2 and S3, the electrochemical polymerization uses a three-electrode system.

4. The method for preparing the polythiophene-based active layer according to claim 3, characterized in that, In steps S2 and S3, the electrolytes in the electrolyte solution are each independently tetramethylammonium tetrafluoroborate. And / or, in steps S2 and S3, the solvent in the electrolyte solution is propylene carbonate, each independently. And / or, in step S2, the molar ratio of N-tert-butoxycarbonyl-3-aminothiophene to the electrolyte solution is 1:1.5 to 2.5; And / or, in step S3, the molar ratio of 3,4-(2,2-dimethylpropenedioxy)thiophene to the electrolyte solution is 1:1.5 to 2.

5.

5. The method for preparing the polythiophene-based active layer according to claim 3, characterized in that, In step S2, the first cyclic voltammetric scan rate is 50mV / s to 100mV / s; And / or, in step S3, the second cyclic voltammetric scan rate is 20mV / s to 100mV / s; And / or, in steps S2 and S3, the scanning period for both the first cyclic voltammetric scan and the second cyclic voltammetric scan is 1 to 50 times.

6. The method for preparing the polythiophene-based active layer according to claim 1, characterized in that, Step S3 is followed by a deprotection process and an annealing process performed sequentially.

7. The method for preparing the polythiophene-based active layer according to claim 6, characterized in that, The deprotection treatment involves immersing the product obtained in step S3 in an acidic solution. And / or, the annealing process is performed under inert gas protection; And / or, the annealing temperature is 100℃~180℃; And / or, the heating rate of the annealing treatment is 2℃ / min to 10℃ / min; And / or, the holding time for the annealing treatment is 15 min to 60 min.

8. The method for preparing the polythiophene-based active layer according to claim 7, characterized in that, The acidic solution is a mixture of trifluoroacetic acid and dichloromethane.

9. A polythiophene-based active layer, characterized in that, It is prepared by the method for preparing the polythiophene-based active layer according to any one of claims 1-8.

10. The application of the polythiophene-based active layer as described in claim 9 in the field of organic solar cells.

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