Method for recycling of an organic solar cell device

Abstract

The application discloses a recycling method of an organic solar cell device, which comprises recycling a photoactive layer in a solar cell, specifically, soaking a waste organic solar cell in an organic solvent for dissolution, taking out a bottom electrode which is not dissolved, filtering an organic solution, vacuumizing the organic solution, and obtaining a photoactive layer material. The application solves the problem of high preparation cost of the organic solar cell by recycling the active layer photovoltaic material from the waste organic solar cell and the material loss and the bottom electrode in the film preparation process. Under the same device preparation process conditions, the recycled photoactive layer material does not need to be readjusted in proportion and directly participates in the preparation of the battery device, and the photoelectric conversion efficiency of the battery device is close to that of the original device. The bottom electrode and the active layer photovoltaic material can be recycled for multiple times. Experimental verification shows that the material can be reused for more than twice.

Description

Technical Field

[0001] This invention relates to the field of organic solar cell technology, and more specifically to a method for recycling organic solar cell devices. Background Technology

[0002] Organic polymer solar cells, as a novel type of photovoltaic device, possess unique advantages such as fewer fabrication processes, large-area solution processing, and flexibility (bending and folding), making them a valuable complement to silicon-based solar cells. Recently, organic polymer solar cells have made significant progress in energy conversion efficiency, with numerous publications reporting device efficiencies of 18%-19%, and even potentially exceeding 20%, demonstrating a strong application trend. Nevertheless, compared to silicon-based solar cells, organic polymer solar cells require further research in energy conversion efficiency, stability, and lifetime, as well as optimization of fabrication methods and cost control to maximize their competitiveness.

[0003] Currently, organic solar cells typically employ a sandwich structure, comprising a transparent bottom electrode, a hole transport layer, an electron transport layer, an active layer, and a metal electrode. The active layer can be a binary or ternary hybrid heterojunction, a stacked structure, or a double (or multi)-layer planar heterojunction. In organic solar cells, the active layer is the part that converts light into electricity and is also the most expensive component. For example, in high-performance photovoltaic systems like PM6:L8-BO, one gram of PM6 typically costs over 20,000 yuan, and L8-BO also costs over 10,000 yuan. However, for bulk heterojunctions, their structural stability is affected by factors such as light, heat, water, and oxygen, leading to aging and further causing device performance degradation, or even failure. Active layer aging mainly falls into two categories: first, degradation of material molecules due to high-energy light; and second, changes in the donor and acceptor phase structures within the active layer. Once the active layer undergoes severe aging, the device will become unusable. This significantly increases the manufacturing cost of organic solar cells. To reduce the manufacturing cost of organic solar cells, this application focuses on the recycling of active layer photovoltaic materials. Specifically, it involves two aspects: first, extracting and reusing the aged active layer from discarded organic solar cells; and second, collecting and reusing materials lost during the film-forming process (such as materials ejected during spin-coating). This aims to achieve the fabrication of high-performance, low-cost organic solar cells, enhancing their application potential and competitiveness. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the reuse of photoactive layer materials in organic solar cells, specifically a method for recycling organic solar cell devices, which enables the fabrication of high-performance, low-cost organic solar cells.

[0005] The objective of this invention is achieved through the following technical solution: A method for recycling organic solar cell devices is characterized by: recovering the photoactive layer from the solar cell, specifically by immersing the waste solar cell in an organic solvent for dissolution, then removing the undissolved bottom electrode to obtain an organic solution, and sequentially filtering and vacuuming the organic solution to obtain the photoactive layer material.

[0006] Furthermore, the organic solvent includes at least one of chloroform, dichloromethane, toluene, o-xylene, mesitylene, o-dichlorobenzene, chlorobenzene, and carbon disulfide.

[0007] More preferably, the organic solvent is composed of at least one of dichloromethane, toluene, o-xylene, mesitylene, o-dichlorobenzene, chlorobenzene, carbon disulfide, and chloroform, and chloroform in a volume ratio of 0.1:0.9 to 0.4:0.6.

[0008] More preferably, the organic solvent is composed of chloroform and chlorobenzene in a volume ratio of 0.8:0.2.

[0009] Furthermore, the photoactive layer of the solar cell can be any one of the following: all polymers, polymer fullerenes, polymer non-fullerenes, all small molecules, and small molecule donor polymer acceptors.

[0010] Furthermore, the all-polymer compounds include, but are not limited to, PM6:PY-IT or PM6:PTQ10:PY-IT; the polymer / fullerene compounds include, but are not limited to, PTB7-Th:PC. 71 BM or PTB7-Th:ICBA:PC 71 BM; Polymer / non-fullerenes include, but are not limited to, D18:Y6 or PM6:IT-4F:ITIC; All small molecules include, but are not limited to, BTR-Cl:BO-4Cl or B1:BO-2Cl:BO-4Cl; Small molecule donor polymer acceptors include, but are not limited to, BTR-Cl:PYT.

[0011] During the recycling process, if the active layer material is not completely dissolved, it will cause an imbalance in the donor-acceptor ratio, resulting in low photoelectric conversion efficiency of the solar cells used for reprocessing. Furthermore, if excess impurities are introduced during solvent dissolution of the active layer material, it will also deteriorate the charge transport performance of the active layer material and increase charge recombination, ultimately leading to unsatisfactory performance of the recycled solar cells. In this invention, by selecting a suitable organic solvent for dissolution, and specifically using at least one of dichloromethane, toluene, o-xylene, mesitylene, o-dichlorobenzene, chlorobenzene, and carbon disulfide combined with trichlorotoluene to dissolve the active layer, the active layer material can be efficiently dissolved while minimizing the introduction of impurities.

[0012] Furthermore, the filtration process involves filtering the organic solution using a multi-layer filter composed of 50-100 mesh polyester fiber mesh. After the filtered organic solution is allowed to stand for 10 hours, it is then filtered again using a large-mesh multi-layer filter composed of 120-420 mesh polyester fiber mesh.

[0013] If the interface layer material cannot be fully filtered out from the organic solution during the recycling process of the photoactive layer, it will not only affect the morphology of the active layer during its preparation, but also affect the charge transport and recombination performance, thus reducing the efficiency of the organic solar cell. By selecting a suitable organic solvent and combining it with the above-mentioned filtration treatment, impurities such as metal electrodes and interface layer materials in the solution can be removed efficiently.

[0014] Furthermore, this method is primarily designed for the co-recycling and reuse of identical active layers at the same ratio, and is not suitable for the mixed recycling of different active layer systems, as it is difficult to estimate the ratio between donor and acceptor materials. This invention, through the effective coordination and control of the above steps, successfully recovers recyclable photovoltaic materials. By recovering the bottom electrode and the recovered active layer photovoltaic materials, the manufacturing cost of devices can be reduced and the utilization rate of photovoltaic materials can be improved.

[0015] Furthermore, the bottom electrode in the solar cell may include, but is not limited to, ITO, FTO, AZO, metal mesh, or nanowires.

[0016] Furthermore, the vacuuming time is set according to the volume of the organic solution and the boiling point of the solvent, and the vacuum degree is controlled at 0.08~-0.1 MPa to prevent the organic solution from boiling too quickly and spraying out due to excessively rapid changes in vacuum degree.

[0017] Most specifically, a method for recycling an organic solar cell device is characterized by comprising the following steps: (1) The solar cell and the collected PM6:IT-4F photovoltaic material lost during the film-making process are soaked in an organic solvent for 12 hours to dissolve them. The organic solvent includes at least one of dichloromethane, toluene, o-xylene, mesitylene, o-dichlorobenzene, chlorobenzene and trichloromethane, and trichloromethane in a volume ratio of 0.1:0.9~0.4:0.6. The photoactive layer material includes, but is not limited to, PM6:PY-IT, PM6:PTQ10:PY-IT, PM6:IT-4F:ITIC, D18:Y6, PTB7-Th:ICBA:PC 71 BM, PTB7-Th:PC 71 BM, BTR-Cl:BO-4Cl, B1:BO-2Cl:BO-4Cl or BTR-Cl:PYT; (2) Filter out the undissolved transparent bottom electrode in the organic solvent to obtain an organic solution. Then filter the organic solution with a multi-layer filter composed of 50-100 mesh polyester fiber mesh. After the filtered organic solvent is left to stand for 10 h, filter it again with a large mesh multi-layer filter composed of 120-420 mesh polyester fiber mesh to remove the metal electrode and interface material. The metal electrode includes, but is not limited to, Al, Au or Ag. The transparent bottom electrode includes, but is not limited to, ITO, FTO or AZO. The interface material includes, but is not limited to, MoO3, ZnO or LiF. (3) After vacuum treatment of the organic solvent obtained in step (2), the photoactive layer material is recovered, and the recovered photoactive layer material is added to the organic solvent to prepare a precursor solution for later use. (4) According to the structure of organic solar cell devices, the bottom interface layer, active layer, top interface layer and top electrode are prepared sequentially; (5) When the active layer material is recycled and reused again, steps (1) to (4) are repeated.

[0018] The present invention has the following technical effects: This invention recycles and reuses the active layer photovoltaic material, as well as material losses during the film-forming process and the bottom electrode, from discarded organic solar cells, greatly solving the problem of high manufacturing costs for organic solar cells. Under the same device fabrication process conditions, the recycled photoactive layer material does not require readjustment of the donor-acceptor ratio, and the photoelectric conversion efficiency of the battery device directly involved in the fabrication is close to that of the original device. This allows for multiple recycling of the bottom electrode and active layer photovoltaic material; experimental verification shows that this method can achieve material reuse more than twice. Attached Figure Description

[0019] Figure 1 : Schematic diagram of the present invention for recycling photoactive layer material in organic solar cells.

[0020] Figure 2 JV curve of the device based on PM6:IT-4F organic solar cell system in Example 1, which utilizes photovoltaic materials for recycling.

[0021] Figure 3 JV curve of the device based on PM6:IT-4F organic solar cell system in Example 2, which utilizes photovoltaic materials for recycling.

[0022] Figure 4 Example 3: JV curve of a device based on PM6:PY-IT organic solar cell system utilizing recycled photovoltaic materials. Detailed Implementation

[0023] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0024] Example 1 A method for recycling an organic solar cell device includes the following steps: (1) A batch of discarded ITO / ZnO / PM6:IT-4F / MoO3 / Ag solar cells and PM6:IT-4F photovoltaic materials lost during the film-making process were soaked in an organic solvent for 12 hours to dissolve them. The organic solvent was chloroform. (2) Remove the bottom electrode from the solution and use a 50-100 mesh multilayer polyester fiber mesh filter to fully filter out the suspended silver electrode from the solution. After standing for 10 h, use a 120-420 mesh multilayer polyester fiber mesh filter to filter out some impurities and interface materials that are insoluble in the solution, and obtain an organic solution containing PM6:IT-4F. (3) After vacuum treatment of the organic solution obtained in step (2), the photoactive layer material PM6:IT-4F is recovered. The recovered photoactive layer material PM6:IT-4F is added to a mixed organic solvent with a volume ratio of chlorobenzene:1,8-diiodooctane = 99.5%:0.5% to prepare an active layer precursor solution with a concentration of 20 mg / mL. The solution is fully dissolved at 400 rpm and 40°C for later use. The recovered bottom electrode ITO is ultrasonically treated in chloroform and then ultrasonically treated in 3% dilute lactic acid solution for later use. (4) According to the structure of organic solar cell devices, the ITO cleaned in step (3) is used as the bottom electrode of the organic solar cell. First, ZnO precursor solution is spin-coated on the surface of the ITO electrode to prepare the ZnO electron transport layer (the precursor solution is: zinc acetate: ethylene glycol methyl ether: ethanolamine = 0.1 g: 1 mL: 28 uL, spin-coating process: 4000 rpm, 30 s, annealing process: 200℃, 30 min). Then, the active layer precursor solution prepared in step (3) is spin-coated (the spin-coating process is: 1800 rpm, 40 s, annealing process: 120℃, 10 min). Then, it is placed in a vacuum of 10 -4 In a vacuum chamber of Pa, an 8 nm thick MoO3 hole transport layer and a 100 nm thick Ag electrode were successively deposited to obtain an organic solar cell with an ITO / ZnO / PM6:IT-4F / MoO3 / Ag structure.

[0025] Repeat steps (1) to (4) for recycling and reuse. The device performance test results are as follows: Figure 2 As shown, the photoelectric conversion efficiency of the organic solar cell prepared by first recycling the active layer material PM6:IT-4F is 13.01%, and the photoelectric conversion efficiency of the solar cell prepared by recycling the photoactive layer PM6:IT-4F again is 10.23%. This proves that the recycling method can efficiently recover and utilize the photoactive layer.

[0026] Example 2 The photoactive layer material PM6:IT-4F was recovered using the same ITO / ZnO / PM6:IT-4F / MoO3 / Ag solar cell as in Example 1. The difference was that the organic solvent used to soak and dissolve the photoactive layer was composed of chloroform and toluene in a volume ratio of 0.6:0.4; the remaining steps were the same as in Example 1.

[0027] The performance test results of organic solar cells with an ITO / ZnO / PM6:IT-4F / MoO3 / Ag structure prepared from the recovered PM6:IT-4F are as follows: Figure 3 As shown, the photoelectric conversion efficiency of the solar cell prepared by the first recycling is 13.2%. After two more recycling cycles of the photoactive layer PM6:IT-4F, the photoelectric conversion efficiencies of the prepared solar cells are 12.1% and 10.3% respectively. Compared with Example 1, the performance of the photoactive layer PM6:IT-4F decreased less during the recycling process.

[0028] Example 3 A method for recycling an organic solar cell device comprises the following steps: (1) A batch of discarded FTO / PEDOT:PSS / PM6:PY-IT / LiF / Al structured solar cells and collected PM6:PY-IT photovoltaic materials lost during film preparation were soaked in an organic solvent for 12 hours to dissolve them. The organic solvent was composed of chloroform and chlorobenzene in a volume ratio of 0.8:0.2. (2) Remove the bottom electrode to obtain an organic solution. Use a 50-100 mesh multilayer polyester fiber mesh filter to filter out the suspended silver electrode from the solution. After standing for 10 h, use a 120-420 mesh multilayer polyester fiber mesh filter to filter out some impurities and interface materials that are insoluble in the solution to obtain an organic solution containing PM6:PY-IT. (3) After vacuum treatment of the organic solution obtained in step (2), the photoactive layer material PM6:PY-IT is recovered. The recovered photoactive layer material is added to an organic solvent (chloroform and chloronaphthalene are composed of 99%:1% by volume) to prepare a precursor solution with a concentration of 14 mg / mL. The solution is fully dissolved at 500 rpm and 40°C for 4 h for later use. The recovered FTO is ultrasonically treated in chloroform and then ultrasonically treated in 3% dilute lactic acid solution for later use. (4) Using the recycled and cleaned FTO as the bottom electrode, according to the structure of organic solar cell devices, a PEDOT:PSS layer was prepared on the surface of the FTO electrode (spin coating process: 4000 rpm, 30 s, annealing process: 150℃, 15 min), and then the precursor solution prepared in step (3) was spin coated to prepare the active layer (spin coating process: 3000 rpm, 30 s, annealing process: 95℃, 5 min), and then the active layer was prepared by spin coating. -4 An organic solar cell with an FTO / PEDOT:PSS / PM6:PY-IT / LiF / Al structure was fabricated by depositing a 1 nm thick LiF hole transport layer and a 100 nm thick Al electrode in a vacuum chamber of Pa.

[0029] (5) Repeat steps (1) to (4) twice more for recycling, and then perform performance testing. The performance results of devices prepared with different recycling cycles are as follows: Figure 4 As shown, when PM6:PY-IT was first used to prepare a battery, its photoelectric conversion efficiency was 14.40%. After two cycles, the device efficiency was still 9.56%, indicating that this recycling method is effective.

[0030] Example 4 A method for recycling an organic solar cell device includes the following steps: (1) A batch of ITO / ZnO / BTR-Cl:Y6 / MoO3 / Ag solar cells and BTR-Cl:Y6 photovoltaic materials lost during the film-making process were soaked in an organic solvent for 12 hours to dissolve them. The organic solvent was composed of chloroform and carbon disulfide in a volume ratio of 0.9:0.1. (2) Remove the bottom electrode to obtain an organic solution. Use a 50-100 mesh multilayer polyester fiber mesh filter to filter out the suspended silver electrode from the solution. After standing for 10 h, use a 120-420 mesh multilayer polyester fiber mesh filter to filter out some impurities and interface materials that are insoluble in the solution to obtain an organic solution containing BTR-Cl:Y6. (3) After vacuum treatment of the organic solvent obtained in step (2), the photoactive layer material is recovered. The recovered photoactive layer material BTR-Cl:Y6 is dissolved in chloroform at a mass ratio of 1.6:1, with a total concentration of 16 mg / mL. It is then fully dissolved at 500 rpm and 40°C for 4 h to prepare the active layer precursor solution for later use. (4) According to the structure of organic solar cell devices, first spin-coat a ZnO precursor solution on the surface of the ITO electrode to prepare a ZnO electron transport layer (the precursor solution is: zinc acetate: ethylene glycol methyl ether: ethanolamine = 0.1 g: 1 mL: 28 uL, spin-coating process: 4000 rpm, 30 s, annealing process: 200℃, 30 min), then spin-coat the active layer precursor solution prepared in step (3) (spin-coating process: 2000 rpm, 50 s, annealing process: 120℃, 10 min), and then place it in a vacuum of 10 -4 In the vacuum chamber of Pa, an 8 nm thick MoO3 hole transport layer and a 100 nm thick Ag electrode were successively deposited to obtain an organic solar cell with an ITO / ZnO / BTR-Cl:Y6 / MoO3 / Ag structure. (5) When the active layer material is recycled and reused again, steps (1) to (4) are repeated. It was found that the photoelectric conversion efficiency of the battery made based on BTR-Cl:Y6 was 9.7% when it was first used, and the efficiency of the same device made by recycling BTR-Cl:Y6 again was still 7.6%.

[0031] Example 5 A method for recycling an organic solar cell device includes the following steps: (1) A batch of ITO / ZnO / BTR-Cl:PYT / MoO3 / Ag solar cells and BTR-Cl:PYT photovoltaic materials lost during the film-making process were soaked in an organic solvent for 12 hours to dissolve the active layer. The organic solvent was composed of chloroform and carbon disulfide in a volume ratio of 0.6:0.4. (2) Remove the bottom electrode to obtain an organic solution. Use a 50-100 mesh multilayer polyester fiber mesh to filter out the suspended silver electrode from the solution. After standing for 10 h, use a 120-420 mesh multilayer polyester fiber mesh to filter out some impurities and interface materials that are insoluble in the solution to obtain an organic solution containing BTR-Cl:PYT. (3) After vacuum treatment of the organic solvent obtained in step (2), the photoactive layer material BTR-Cl:PYT is recovered. The recovered photoactive layer material BTR-Cl:PYT is dissolved in chloroform:1,8-diiodooctane (99.5%:0.5%) at a mass ratio of 3:1, with a total concentration of 16 mg / mL. The solution is fully dissolved at 500 rpm and 50℃ for 4 h to prepare a precursor solution for later use. (4) According to the structure of organic solar cell devices, first spin-coat a ZnO precursor solution on the surface of the ITO electrode to prepare a ZnO electron transport layer (the precursor solution is: zinc acetate: ethylene glycol methyl ether: ethanolamine = 0.1 g: 1 mL: 28 uL, spin-coating process: 4000 rpm, 30 s, annealing process: 200℃, 30 min), then spin-coat the active layer precursor solution prepared in step (3) (spin-coating process: 3000 rpm, 50 s, annealing process: 120℃, 10 min), and then place it in a vacuum of 10 -4 In the vacuum chamber of Pa, an 8 nm thick MoO3 hole transport layer and a 100 nm thick Ag electrode were successively deposited to obtain an organic solar cell with an ITO / ZnO / BTR-Cl:PYT / MoO3 / Ag structure. (5) When the active layer material is recycled and reused again, steps (1) to (4) are repeated. It was found that the photoelectric conversion efficiency of the battery made based on BTR-Cl:PYT was 4.4% when it was first used, and the efficiency of the same device made by recycling BTR-Cl:PYT again was still 3.8%.

Claims

1. A method for recycling organic solar cell devices, characterized in that: The method includes recovering the photoactive layer from solar cells. Specifically, waste solar cells are immersed in an organic solvent for dissolution. Then, the undissolved bottom electrode is removed to obtain an organic solution. The organic solution is then filtered and vacuumed to obtain the photoactive layer material. The organic solvent is composed of at least one of dichloromethane, toluene, o-xylene, mesitylene, o-dichlorobenzene, chlorobenzene, carbon disulfide, and chloroform, with chloroform in a volume ratio of 0.1:0.9~0.4:0.

6.

2. The method for recycling an organic solar cell device as described in claim 1, characterized in that: The photoactive layer in the solar cell can be any one of the following: all polymers, polymer / fullerenes, polymer / non-fullerenes, all small molecules, and small molecule donors / polymer acceptors.

3. The method for recycling an organic solar cell device as described in claim 2, characterized in that: The full polymers include, but are not limited to, PM6:PY-IT or PM6:PTQ10:PY-IT; the polymers / fullerenes include, but are not limited to, PTB7-Th:PC. 71 BM or PTB7-Th:ICBA:PC 71 BM; Polymer / non-fullerenes include, but are not limited to, D18:Y6 or PM6:IT-4F:ITIC; All small molecules include, but are not limited to, BTR-Cl:BO-4Cl or B1:BO-2Cl:BO-4Cl; Small molecule donor polymer acceptors include, but are not limited to, BTR-Cl:PYT.

4. A method for recycling an organic solar cell device as described in any one of claims 1-3, characterized in that: The filtration process involves filtering the organic solution using a multi-layer filter composed of 50-100 mesh polyester fiber mesh. After the filtered organic solution is left to stand for 10 hours, it is then filtered again using a multi-layer filter composed of 120-420 mesh polyester fiber mesh.

5. A method for recycling organic solar cell devices, characterized in that, Includes the following steps: (1) The solar cell and the photovoltaic material lost during the film-making process are soaked in an organic solvent for 12 hours to dissolve them. The organic solvent includes at least one of dichloromethane, toluene, o-xylene, mesitylene, o-dichlorobenzene, chlorobenzene, carbon disulfide, and chloroform, and chloroform is composed of chloroform and the aforementioned solvent in a volume ratio of 0.1:0.9~0.4:0.

6. The photoactive layer material includes, but is not limited to, PM6:PY-IT, PM6:PTQ10:PY-IT, PM6:IT-4F, D18:Y6, PTB7-Th:ICBA:PC. 71 BM, PTB7-Th:PC 71 BM, BTR-Cl:BO-4Cl, B1:BO-2Cl:BO-4Cl or BTR-Cl:PYT; (2) Filter out the undissolved transparent bottom electrode, metal electrode and interface material to obtain an organic solution. The metal electrode includes, but is not limited to, Al, Au or Ag. The transparent bottom electrode includes, but is not limited to, ITO, FTO or AZO. The interface material includes, but is not limited to, MoO3, ZnO or LiF. (3) After vacuum treatment of the organic solution obtained in step (2), the photoactive layer material is recovered, and the recovered photoactive layer material is added to an organic solvent to prepare a precursor solution for later use. (4) According to the structure of organic solar cell devices, the bottom interface layer, active layer, top interface layer and top electrode are prepared sequentially; (5) When the active layer material is recycled and reused again, steps (1) to (4) are repeated.

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