Organic photovoltaic film stretching performance improvement method, organic solar cell and preparation method

Abstract

This invention relates to the field of photovoltaic device fabrication technology, specifically to a method for improving the tensile properties of organic photovoltaic thin films, organic solar cells, and their fabrication methods. The method for preparing the organic photovoltaic thin film involves mixing electron donor materials, electron acceptor materials, and an organic solvent to form organic photovoltaic raw materials. An organic photovoltaic thin film is then prepared based on these raw materials. A flexible agent is added to the organic photovoltaic raw materials, with the added mass being 0.2-20% of the total mass of the electron donor and acceptor materials. In this invention, adding a small amount of flexible agent to the donor and acceptor raw materials of the organic photovoltaic thin film can improve the aggregated state structure of the organic photovoltaic thin film, which is beneficial to photovoltaic performance. This improves the stretchability of the active layer while maintaining or improving its photovoltaic performance, reducing the modulus, lowering costs, and enhancing conductivity and cyclic tensile stability.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic device fabrication technology, specifically to a method for improving the stretching properties of organic photovoltaic thin films, and an organic solar cell and its fabrication method. Background Technology

[0002] Organic solar cells offer significant advantages such as flexibility, lightweight, low cost, and ease of large-area fabrication. Based on these advantages, they can be fabricated into thin films, better adapting to various shapes and curved surfaces, making them ideal for wearable device applications. Therefore, developing organic solar cells with good stretchability is an effective strategy for optimizing wearable technology.

[0003] Currently, most high-efficiency organic solar cells (OSCs) use active layers based on polymer donor-acceptor blends. These blends exhibit poor mechanical properties, with crack initiation strain less than 10% and an elastic modulus around 1 GPa, failing to meet the requirements for flexible wearable applications of OSCs. In recent years, several methods have been proposed to improve the tensile properties of OSC thin films. These include introducing polymers with high elasticity and good mechanical properties, such as polyurethane, silicone rubber, and polyether esters, into the organic layer material; or designing dynamic polymers using dynamic covalent or non-covalent interactions. These dynamic bonds can break under stress and reform after stress release, endowing the film with self-healing and excellent tensile recovery capabilities. However, while these methods impart better tensile properties, they may also sacrifice some photoelectric conversion efficiency. Therefore, improving the mechanical properties of the active layer while maintaining or enhancing the photoelectric conversion efficiency of OSCs remains a problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving the tensile properties of organic photovoltaic thin films, an organic solar cell and a preparation method thereof, so as to improve the mechanical properties of the active layer while maintaining or improving the photoelectric conversion efficiency of the organic solar cell.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for improving the tensile properties of organic photovoltaic thin films, wherein the organic photovoltaic thin film is prepared by mixing an electron donor material, an electron acceptor material and an organic solvent to form an organic photovoltaic raw material, and then preparing an organic photovoltaic thin film based on the organic photovoltaic raw material, characterized in that: a flexible agent is added to the organic photovoltaic raw material, and the added mass of the flexible agent is 0.2-20% of the total mass of the electron donor material and the electron acceptor material.

[0007] An organic solar cell includes a conductive substrate, a hole transport layer, an organic photovoltaic thin film active layer, an electron transport layer, and a metal electrode. The organic photovoltaic thin film active layer is prepared by using an organic photovoltaic thin film tensile property enhancement method to improve its tensile properties, and the mass ratio of electron donor material to electron acceptor material in the organic photovoltaic thin film active layer is 0.2-10.

[0008] Preferably, the flexible agent in the active layer of the organic photovoltaic thin film is selected from p-type flexible agents or n-type flexible agents, wherein the p-type flexible agent is selected from B(C6F5)3, CuI, C 60 F 36 C 60 F 48 The n-type flexible agent is selected from one of F2-TCNQ, F4-TCNQ, F6-TCNNQ, MnTPPCl, CoTPP, C60, FeCl3, I2, MoO3, Mo(tfd)3, Mo(tfd-COCF3)3, Mn3O4, TCNQ, and V2O5; the n-type flexible agent is selected from one of CsF, PEI, PI-Ph-PI, TP-TPI, FPI, TBAF, PEIE, Cs2CO3, and CoCp2.

[0009] The organic solvent in the active layer of the organic photovoltaic thin film is selected from one of chloroform, chlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene, or tetrahydrofuran;

[0010] The electron donor material in the active layer of the organic photovoltaic thin film is selected from one of the following: poly(p-phenylenevinylene), poly(arylvinylene), poly(p-phenylene), poly(aryl), polythiophene, polyquinoline, phthaloline, phthalocyanine, or copolymers composed of electron-withdrawing conjugated units and electron-donating conjugated units. The electron acceptor material in the active layer of the organic photovoltaic thin film is selected from one of the following: fullerene or its derivatives, perylene or its derivatives, naphthalene or its derivatives, imide acceptors, fused-ring electron acceptors, and non-fused-ring electron acceptors.

[0011] The electron-withdrawing conjugating unit is one of pyrrolopyrroledione, benzothiadiazole, thienopyrroledione, or thienothiaphene, and the electron-donating conjugating unit is one of carbazole, fluorene, benzodithiaphene, benzodifuran, dithienobenzene, or indole.

[0012] Preferably, the active layer of the organic photovoltaic thin film is deposited on the surface of the hole transport layer by spin coating, blade coating or printing, and the thickness of the active layer of the organic photovoltaic thin film is 10-1000 nm.

[0013] Preferably, the conductive substrate is selected from glass or thin film containing metal oxides, graphene, carbon nanotubes or metal nanowires.

[0014] Preferably, the hole transport layer is a PEDOT:PSS layer with a thickness of 20-90 nm.

[0015] Preferably, the electron transport layer is PFN-Br or PDINO, with a thickness of 10 nm.

[0016] Preferably, the metal electrode material is selected from one of the following metals: calcium, magnesium, barium, aluminum, silver, gold, copper, nickel, zinc, titanium, manganese, iron, platinum, or molybdenum, and the thickness of the metal electrode is 100-300 nm.

[0017] A method for preparing an organic solar cell includes the following steps:

[0018] S1. The conductive substrate is ultrasonically cleaned sequentially with detergent dilution, deionized water, acetone and isopropanol. Then, the surface isopropanol solvent is dried with nitrogen. Finally, the conductive substrate is treated with ultraviolet ozone for 30 minutes using an ultraviolet ozone cleaner.

[0019] S2. Spin-coat PDEOT:PSS solution onto the surface of the ozone-treated conductive substrate at 4000 r / min for 30 s. Then place it in a forced-air oven to dry at 150 ℃ for 20 min to obtain a dry hole transport layer.

[0020] S3. The conductive substrate with the hole transport layer spin-coated is transferred into the glove box. The raw material of the organic photovoltaic thin film active layer is spin-coated on the surface of the hole transport layer under spin-coating conditions of 2500 r / min for 60 s. Then, the conductive substrate is placed on a 100°C hot table for 10 min to perform thermal annealing treatment on the organic photovoltaic thin film active layer. The electron donor material in the raw material of the organic photovoltaic thin film active layer is PTB7-Th, the electron acceptor material is N2200, the softening agent is F4-TCNQ, and the organic solvent is chloroform. The mass ratio of PTB7-Th to N2200 is 1.

[0021] S4. Spin-coat a PFN-Br electron transport layer onto the surface of the active layer of the annealed organic photovoltaic thin film under spin-coating conditions of 3000 r / min and 40 s.

[0022] S5. Place the conductive substrate with the PFN-Br electron transport layer spin-coated into a vacuum evaporation equipment, and deposit a 100nm thick metal electrode Ag on the PFN-Br surface to obtain an organic solar cell.

[0023] Preferably, the raw materials for the active layer of the organic photovoltaic thin film are obtained by heating and stirring at 45°C overnight.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] In this invention, a small amount of flexible agent is added to the donor and acceptor raw materials of organic photovoltaic thin films, which can improve the aggregated state structure of organic photovoltaic thin films and is beneficial to photovoltaic performance. Thus, while maintaining or improving the photovoltaic performance of the active layer, the stretchability of the active layer is improved, the modulus is reduced, the cost is reduced, the conductivity and cyclic tensile stability are improved. Furthermore, when this method is applied to organic solar cells, the conductivity of organic solar cells can be improved, the cyclic tensile stability of organic solar cells can be improved, and the cost of organic solar cells can be reduced without changing other structures of organic solar cells. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the organic solar cell device structure of the present invention;

[0028] Figure 2 The crack initiation strain histogram of the organic photovoltaic thin film (PM6:BTP-eC9) prepared in this invention when the F2-TCNQ accounts for 0-10% of the total mass of the donor and acceptor is shown.

[0029] Figure 3 The strain-stress curve of the organic photovoltaic thin film (PTB7-Th:N2200) prepared in this invention was obtained by the underwater thin film testing method when the F4-TCNQ accounted for 0-10% of the total mass ratio of donor and acceptor.

[0030] Figure 4 This diagram illustrates the change in mobility of the organic solar cell (PTB7-Th:N2200) prepared in this invention under different stretch-release cycles at 50% strain when F4-TCNQ accounts for 1% of the total donor and acceptor mass. Detailed Implementation

[0031] 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.

[0032] Example 1:

[0033] In this embodiment, the electron donor material used in the organic photovoltaic raw materials is 2 mg of PM6, the electron acceptor material is 2.5 mg of BTP-eC9, the softening agent is 0.009 mg of F2-TCNQ, the solvent is chloroform, the substrate is polydimethylsiloxane (PDMS), and the specific process for preparing the organic photovoltaic thin film is as follows:

[0034] 1) The glass substrate was ultrasonically cleaned with isopropanol, detergent dilution, deionized water, acetone and isopropanol in sequence for 15 minutes. Then the isopropanol solvent on the surface was dried with nitrogen and then treated with ultraviolet ozone (UV-Ozone) for 25 minutes.

[0035] 2) Spin-coat the PSS dilution (PSS to H2O volume ratio of 1:4) onto the glass substrate at a speed of 5000 r / min for 30s, then dry it in a forced-air oven at 150℃ for 20min, and transfer the glass slide with PSS spin-coated to an inert atmosphere glove box for later use.

[0036] 3) Spin-coat the prepared organic photovoltaic raw materials onto the cooled PSS layer at a speed of 2500 r / min for 30 s to obtain an organic photovoltaic thin film;

[0037] 4) Place the glass slide on a 100℃ hot plate for 10 minutes to perform heat annealing on the organic photovoltaic thin film;

[0038] 5) The organic photovoltaic film is attached to the PDMS substrate (PDMS and curing agent are mixed at a volume ratio of 10:1 and cured at 90°C for 50 minutes). Then, the glass sheet attached to the PDMS substrate is placed in deionized water for several tens of minutes until the PSS layer is dissolved by the deionized water, the glass sheet is detached, and only the active layer film is attached to the PDMS substrate. This realizes the transfer of the organic photovoltaic film from the glass substrate to the PDMS substrate, resulting in a PDMS substrate with organic photovoltaic film.

[0039] Example 2:

[0040] The difference between this embodiment and Example 1 is that: 0.0225 mg of F2-TCNQ organic photovoltaic raw material flexible agent is selected, and the same preparation method as in Example 1 is used to prepare PDMS substrate II with organic photovoltaic thin film.

[0041] Example 3:

[0042] The difference between this embodiment and Example 1 is that: 0.045 mg of F2-TCNQ was selected as the organic photovoltaic raw material softener, and the same preparation method as in Example 1 was used to prepare the PDMS substrate with organic photovoltaic film.

[0043] Example 4:

[0044] The difference between this embodiment and Example 1 is that: 0.09 mg of F2-TCNQ organic photovoltaic raw material flexible agent is selected, and the same preparation method as in Example 1 is used to prepare PDMS substrate four with organic photovoltaic thin film.

[0045] Example 5:

[0046] The difference between this embodiment and Example 1 is that: 0.45 mg of F2-TCNQ was selected as the organic photovoltaic raw material softener, and the same preparation method as in Example 1 was used to prepare the PDMS substrate with organic photovoltaic film.

[0047] Comparative Example 1:

[0048] The difference between this comparative example and Example 1 is that the flexible agent F2-TCNQ is not added, and the same preparation method as in Example 1 is used to prepare the PDMS substrate of ordinary organic photovoltaic film.

[0049] The PDMS substrates 1, ..., PDMS substrate 6 prepared in Examples 1-5 and Comparative Example 1 were sequentially clamped on a stretching machine to conduct mechanical tests on the organic photovoltaic thin films. Simultaneously, observation was performed using a polarizing microscope. The stretching test continued until fine cracks appeared in the active layer film, at which point the tensile strain was taken as the crack initiation strain (e.g., ...). Figure 2 (as shown);

[0050] Conclusion: From Figure 2 It can be seen that adding a small amount of flexible agent during the preparation of organic photovoltaic thin films can effectively improve the stretchability of organic photovoltaic thin films, and as the amount of flexible agent added increases, the stretchability of organic photovoltaic thin films gradually decreases (although the overall stretchability is still higher than that of films without added flexible agent).

[0051] Example 6:

[0052] In this embodiment, 1 mg of PTB7-Th was used as the electron donor, 1 mg of N2200 was used as the electron acceptor, 0.01 mg of F4-TCNQ was used as the flexibility agent, chloroform was used as the solvent, and the organic solar cell was prepared by the following method:

[0053] S1. The conductive substrate is ultrasonically cleaned sequentially with detergent dilution, deionized water, acetone and isopropanol. Then, the surface isopropanol solvent is dried with nitrogen. Finally, the conductive substrate is treated with ultraviolet ozone for 30 minutes using an ultraviolet ozone cleaner.

[0054] S2. Spin-coat PDEOT:PSS solution onto the surface of the ozone-treated conductive substrate at 4000 r / min for 30 s. Then place it in a forced-air oven to dry at 150 ℃ for 20 min to obtain a dry hole transport layer.

[0055] S3. The conductive substrate with the hole transport layer spin-coated is transferred into the glove box. The raw material of the organic photovoltaic thin film active layer is spin-coated on the surface of the hole transport layer under spin-coating conditions of 2500 r / min for 60 s. Then, the conductive substrate is placed on a 100°C hot table for 10 min to perform thermal annealing treatment on the organic photovoltaic thin film active layer. The electron donor material in the raw material of the organic photovoltaic thin film active layer is PTB7-Th, the electron acceptor material is N2200, the softening agent is F4-TCNQ, and the organic solvent is chloroform. The mass ratio of PTB7-Th to N2200 is 1.

[0056] S4. Spin-coat a PFN-Br electron transport layer onto the surface of the active layer of the annealed organic photovoltaic thin film under spin-coating conditions of 3000 r / min and 40 s.

[0057] S5. Place the conductive substrate with the PFN-Br electron transport layer spin-coated into a vacuum evaporation equipment, and deposit a 100nm thick metal electrode Ag on the PFN-Br surface to obtain an organic solar cell.

[0058] Example 7:

[0059] The difference between this embodiment and Example 6 is that: in this embodiment, 0.02 mg of F4-TCNQ is used as the flexibility enhancer, and the organic solar cell II is prepared using the same preparation method as in Example 6.

[0060] Example 8:

[0061] The difference between this embodiment and Example 6 is that: in this embodiment, 0.1 mg of F4-TCNQ is used as the flexibility enhancer, and the organic solar cell is prepared using the same preparation method as in Example 6.

[0062] Comparative Example 2:

[0063] The difference between this comparative example and Example 6 is that the flexible agent F4-TCNQ is not added, and the organic solar cell is prepared using the same preparation method as in Example 6.

[0064] The organic solar cells prepared in Examples 6-8 and Comparative Example 2 were sequentially tested under standard test conditions (AM 1.5, 100mW cm⁻¹). -2 The device performance of the organic solar cell was tested, and the results are shown in Table 1:

[0065] Table 1

[0066]

[0067] Conclusion: As shown in Table 1 above, adding a small amount of flexible agent to the organic photovoltaic film of organic solar cells can improve the energy conversion efficiency of organic solar cells. Furthermore, with the increase of F4-TCNQ content, the photovoltaic performance of organic solar cells first increases and then decreases.

[0068] Example 9:

[0069] In this embodiment, the electron donor material is selected as 1 mg of PTB7-Th, the electron acceptor material is selected as 1 mg of N2200, the flexible agent is selected as F4-TCNQ, and the added mass is (0.01, 0.02, 0.1) mg, that is, F4-TCNQ accounts for (0.5, 1, 5)% of the total mass of donor and acceptor (PTB7-Th+N2200). The solvent is chloroform, the substrate is selected as polydimethylsiloxane (PDMS), and the same preparation method as in Example 1 is used to prepare PDMS substrates seven, eight, and nine with organic photovoltaic thin films.

[0070] Comparative Example 3:

[0071] The difference between this comparative example and Example 9 is that: in this example, F4-TCNQ flexible agent is not added, and the same preparation method as in Example 1 is used to prepare the PDMS substrate of ordinary organic photovoltaic film.

[0072] Tensile tests were performed on the prepared PDMS substrates at scores of 7, 8, 9, and 10 on water to obtain their strain-stress curves, as shown below. Figure 3 As shown;

[0073] Conclusion: Through Figure 3 It can be seen that the tensile properties of the active layer film were significantly improved compared with those without flexible agent (Comparative Example 3). However, the improvement in tensile properties is affected by changes in the content of small molecule flexible agent. As the content of flexible agent increases, the optimization effect first increases and then decreases. Therefore, the content of flexible agent does not necessarily improve the stretchability (ductility) of the active layer of organic solar cells more; a suitable range is still needed.

[0074] Example 10:

[0075] In this embodiment, the electron donor material is selected as 1 mg of PTB7-Th, the electron acceptor material is selected as 1 mg of N2200, the flexible agent is selected as F4-TCNQ, and the mass of F4-TCNQ added is 0.02 mg, that is, F4-TCNQ accounts for 1% of the total mass of donor and acceptor (PTB7-Th+N2200). The solvent is chloroform, the substrate is selected as polydimethylsiloxane (PDMS), and the organic solar cell five is prepared by the same method as in Example 6.

[0076] Comparative Example 4:

[0077] The difference between this comparative example and Example 4 is that F4-TCNQ is not added, and the organic solar cell VI is prepared using the same method as in Example 6.

[0078] The prepared organic solar cells V and VI were characterized using a Keithley 2400 digital source meter (Keithley Source Meter Corporation, USA) in an argon glove box to assess the performance of single-hole devices. Mobility changes after different numbers of cyclic stretching-releasing cycles at 50% strain were tested. Figure 4 As shown.

[0079] Conclusion: Through Figure 4 It can be seen that compared with the sample with added flexible agent, the migration rate of the sample without added flexible agent decreased significantly with the increase of the number of cycles of stretching-release. However, compared with the active layer film without added F4-TCNQ, the migration rate of the active layer film with added F4-TCNQ did not decrease significantly with the increase of the number of cycles.

[0080] In summary, this invention adds a small amount of flexible agent to the donor and acceptor raw materials of organic photovoltaic thin films, which can improve the aggregated state structure of the organic photovoltaic thin films and is beneficial to photovoltaic performance. This improves the stretchability of the active layer, reduces the modulus, lowers the cost, and enhances conductivity and cyclic tensile stability while maintaining or improving the photovoltaic performance of the active layer. Furthermore, applying this method to organic solar cells can improve the conductivity, enhance the cyclic tensile stability, and reduce the cost of organic solar cells without altering other structures. This invention only proposes applying this method to positively mounted organic solar cells; it is also applicable to reverse-mounted organic solar cells, organic light-emitting diodes, organic thin-film transistors, organic photodetectors, etc.

[0081] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An organic solar cell, the solar cell comprising a conductive substrate, a hole transport layer, an organic photovoltaic thin film active layer, an electron transport layer, and a metal electrode, characterized in that: The active layer of the organic photovoltaic thin film is prepared by the following method: an electron donor material, an electron acceptor material, and an organic solvent are mixed to form an organic photovoltaic raw material, and then an organic photovoltaic thin film is prepared based on the organic photovoltaic raw material. A flexibility agent is added to the organic photovoltaic raw material, and the mass of the flexibility agent added is 0.2-20% of the total mass of the electron donor material and the electron acceptor material. The mass ratio of the electron donor material to the electron acceptor material in the active layer of the organic photovoltaic thin film is 0.2-10. The flexible agent in the active layer of the organic photovoltaic thin film is selected from p-type flexible agents or n-type flexible agents. The p-type flexible agent is selected from one of B(C6F5)3, CuI, C60F36, C60F48, F2-TCNQ, F4-TCNQ, F6-TCNNQ, MnTPPCl, CoTPP, C60, FeCl3, I2, MoO3, Mo(tfd)3, Mo(tfd-COCF3)3, Mn3O4, TCNQ, and V2O5. The n-type flexible agent is selected from one of CsF, PEI, PI-Ph-PI, TP-TPI, FPI, TBAF, PEIE, Cs2CO3, and CoCp2. The organic solvent in the active layer of the organic photovoltaic thin film is selected from one of chloroform, chlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene, or tetrahydrofuran; The electron donor material in the active layer of the organic photovoltaic thin film is selected from one of the following: poly(p-phenylenevinylene), poly(arylenevinylene), poly(p-phenylene), poly(arylene), polythiophene, polyquinoline, phthaloline, phthalocyanine, or a copolymer composed of electron-withdrawing conjugated units and electron-donating conjugated units coupled together. The electron acceptor material in the active layer of the organic photovoltaic thin film is selected from one of fullerene or its derivatives, perylene or its derivatives, naphthalene or its derivatives, imide acceptors, fused-ring electron acceptors, and non-fused-ring electron acceptors; The electron-withdrawing conjugated unit is one of pyrrolopyrroledione, benzothiadiazole, thienopyrroledione, or thienothiophene. The electron-donating conjugating unit is one of carbazole, fluorene, benzodithiophene, benzodifuran, dithiophene, or benzo[a]benzene.

2. The organic solar cell according to claim 1, characterized in that: The active layer of the organic photovoltaic thin film is deposited on the surface of the hole transport layer by spin coating, blade coating or printing, and the thickness of the active layer of the organic photovoltaic thin film is 10-1000nm.

3. The organic solar cell according to claim 1, characterized in that: The conductive substrate is selected from glass or thin film containing metal oxides, graphene, carbon nanotubes or metal nanowires.

4. The organic solar cell according to claim 2, characterized in that: The hole transport layer is a PEDOT:PSS layer with a thickness of 20-90nm.

5. The organic solar cell according to claim 1, characterized in that: The electron transport layer is PFN-Br or PDINO, with a thickness of 10 nm.

6. The organic solar cell according to claim 1, characterized in that: The material of the metal electrode is selected from one of the following metals: calcium, magnesium, barium, aluminum, silver, gold, copper, nickel, zinc, titanium, manganese, iron, platinum, or molybdenum, and the thickness of the metal electrode is 100-300 nm.

7. A method for preparing an organic solar cell according to any one of claims 1-6, characterized in that: The following steps are involved: S1. The conductive substrate is ultrasonically cleaned sequentially with detergent dilution, deionized water, acetone and isopropanol. Then, the surface isopropanol solvent is dried with nitrogen. Finally, the conductive substrate is treated with ultraviolet ozone for 30 minutes using an ultraviolet ozone cleaner. S2. Spin-coat PDEOT:PSS solution onto the surface of the ozone-treated conductive substrate at 4000 r / min for 30 s. Then place it in a forced-air oven to dry at 150 ℃ for 20 min to obtain a dry hole transport layer. S3. The conductive substrate with the hole transport layer spin-coated is transferred into the glove box. The raw material of the organic photovoltaic thin film active layer is spin-coated on the surface of the hole transport layer under spin-coating conditions of 2500 r / min for 60 s. Then, the conductive substrate is placed on a 100°C hot table for 10 min to perform thermal annealing treatment on the organic photovoltaic thin film active layer. The electron donor material in the raw material of the organic photovoltaic thin film active layer is PTB7-Th, the electron acceptor material is N2200, the softening agent is F4-TCNQ, and the organic solvent is chloroform. The mass ratio of PTB7-Th to N2200 is 1. S4. Spin-coat a PFN-Br electron transport layer onto the surface of the active layer of the annealed organic photovoltaic thin film under spin-coating conditions of 3000 r / min and 40 s. S5. Place the conductive substrate with the PFN-Br electron transport layer spin-coated into a vacuum evaporation equipment, and deposit a 100nm thick metal electrode Ag on the PFN-Br surface to obtain an organic solar cell.

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