A kind of double-body heterojunction high-efficiency inverted organic solar cell and its preparation method
By optimizing material concentration and thickness through a dual-body heterojunction structure and lamination process, the problem of low efficiency in inverted organic solar cells was solved, achieving high-efficiency photoelectric conversion and stability, with a photoelectric conversion efficiency of 20.27%.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGXI UNIV
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-05
AI Technical Summary
Existing inverted organic solar cells suffer from insufficient efficiency, especially due to reproducibility issues caused by complex multilayer deposition processes and energy level mismatch and interface contact problems between different active layer materials.
A dual-body heterojunction structure was adopted, using D18:L8-BO and PBQx-TCl:PYIT as the donor and acceptor materials. A device structure of Glass/ITO/ZnO/PC61BM/D18:L8-BO/PBQx-TCl:PYIT/MoO3/Ag was constructed through a lamination process. The concentration of materials and the film thickness were optimized, and a clear interface was formed by combining the lamination film transfer printing method.
It achieves high-efficiency photoelectric conversion with a wide spectral response, excellent short-circuit current density, high fill factor, and photoelectric conversion efficiency of 20.27%, while improving device stability and thermal cycling stability.
Smart Images
Figure CN122161264A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solar cell technology, and in particular to a high-efficiency inverted organic solar cell with a dual heterojunction and its preparation method. Background Technology
[0002] Organic solar cells (OSCs) have attracted considerable attention due to their solution processability, lightweight nature, tunable optical properties, and multifunctional device structures. Performance improvements have been made through structural modifications, such as bulk heterojunctions, layer-by-layer fabrication, planar heterojunctions, and tandem cells. Selecting donor and acceptor materials with complementary and broad spectral coverage ensures effective photon capture, leading to high photocurrents in OSCs. Tandem OSCs, by connecting multiple sub-cells in series, can achieve higher open-circuit voltages and power conversion efficiencies. However, absorption overlap and current mismatch between sub-cells limit the current in tandem devices. Furthermore, the complex multilayer deposition process required for fabricating tandem OSCs inevitably leads to reproducibility issues, hindering their widespread industrial application.
[0003] To achieve strong spectral coverage and high output photocurrent of the active layer while avoiding reproducibility issues caused by complex multilayer deposition processes, the fabrication of single-junction organic solar cells using a dual-body heterojunction active layer has attracted widespread attention. Dual-body heterojunction layers can be fabricated using various donor-acceptor materials. A unique sequential deposition strategy can avoid the detrimental morphology problems commonly found in traditional ternary blends. The inherent mutual solubility between adjacent organic film layers makes multilayer deposition of organic films, which is often difficult to achieve with sequential deposition, thus hindering the construction of clear interfaces and geometric patterns. Lamination and transfer printing methods can more effectively form multilayer film stacks with clear interfaces, preventing the bottom film from being eroded by the same solvent during continuous film deposition. Currently, due to energy level mismatches between different active layer materials and interfacial contact problems between dual-body heterojunction layers, the performance of devices fabricated using lamination methods cannot yet match that of the latest single-junction and tandem organic solar cells. Summary of the Invention
[0004] To address the above shortcomings, this invention provides a high-efficiency inverted organic solar cell with a dual-body heterojunction and its fabrication method, solving the problem of insufficient efficiency in existing inverted organic solar cells. The specific technical solution is as follows: A method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction includes the following steps: (1) Preparation of the printing substrate structure: S1. ITO substrate pretreatment: The ITO substrate is ultrasonically cleaned and dried for later use; S2. Preparation of Glass / ITO / ZnO: Spin-coating ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, annealing, and then transferring to a glove box (oxygen content <10 ppm; water content <0.1 ppm) to cool to room temperature to obtain Glass / ITO / ZnO. S3. Preparation of Glass / ITO / ZnO / PC 61 BM: Use a pipette to apply 15 μL of PC solution each time. 61 BM solution was spin-coated onto Glass / ITO / ZnO at 3500 rpm for 20 seconds to obtain Glass / ITO / ZnO / PC. 61 BM refers to the printing substrate structure. (2) Preparation of film-forming substrate structure one: Glass / PDMS was prepared by spin-coating D18:L8-BO solution onto Glass / PDMS at 3500 rpm for 20 seconds using a pipette in 15 μL increments to obtain Glass / PDMS / D18:L8-BO, which is the first film-forming substrate structure. (3) Preparation of film-forming substrate structure two: Glass / PDMS was prepared by spin-coating PBQx-TCl:PYIT solution onto Glass / PDMS at 3500 rpm for 20 seconds using a pipette in 15 μL increments to obtain Glass / PDMS / PBQx-TCl:PYIT, which is the second film-forming substrate structure. (4) Laminated film substrate structure: The first film-forming substrate structure is placed over the printing substrate structure. After the D18:L8-BO film makes firm contact with the printing substrate, the PDMS is removed. The second film-forming substrate structure is then placed over the D18:L8-BO film. After the PBQx-TCl:PYIT film makes firm contact with the D18:L8-BO film, the PDMS is removed. The film is then annealed at 80°C for 5 minutes on a constant temperature hot plate to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO / PBQx-TCl:PYIT; the thickness ratio of the D18:L8-BO film to the PBQx-TCl:PYIT film is 80nm:(30-50)nm; (5) Evaporation of hole transport layer and electrode: The Glass / ITO / ZnO / PC 61 MoO3 and silver electrodes were sequentially deposited in a vacuum evaporation chamber using BM / D18:L8-BO / PBQx-TCl:PYIT, while controlling the chamber pressure to be <2×10⁻⁶. -5Pa yields a structure of Glass / ITO / ZnO / PC. 61 Inverted organic solar cells of BM / D18:L8-BO / PBQx-TCl:PYIT / MoO3 / Ag.
[0005] Preferably, in step (1) S1, the ITO substrate pretreatment involves sequentially using a cleaning agent solution, deionized water, acetone, deionized water, and isopropanol to perform ultrasonic cleaning on the ITO substrate, with each step lasting 10-20 minutes, to obtain an ultrasonically cleaned ITO substrate; then, the ultrasonically cleaned ITO substrate is dried using a nitrogen gun, and then placed in the ultraviolet ozone cleaning machine chamber for 25-35 minutes, and then taken out for use.
[0006] Preferably, in step (1) S2, the ZnO solution is prepared as follows: in a 500 mL beaker, 5-15 mmol of anhydrous zinc acetate is dissolved in 125 mL of methanol and heated to 60-70 °C. Then, potassium hydroxide methanol solution with a mass-to-volume ratio of (1-1.1) g:50 mL is slowly added dropwise and reacted for 15-25 min. Then, 1-3 mL of ethanolamine is added, and the mixture is concentrated to a volume of 45-55 mL. Ethyl acetate is added to precipitate the product. After centrifugation, the supernatant is discarded. The precipitate is mixed with anhydrous ethanol and dissolved by ultrasonic treatment to obtain a ZnO solution with a concentration of 25-35 mg / mL.
[0007] Preferably, in step (1) S2, the annealing is performed at 140-160°C for 15-25 minutes on a constant temperature hot plate.
[0008] Preferably, in step (1) S3, the PC 61 The preparation method of BM solution is as follows: In a glove box, PC... 61 BM was dissolved in chloroform to prepare PC with a concentration of 2-5 mg / mL. 61 BM solution.
[0009] Preferably, in steps (2) and (3), the Glass / PDMS is prepared by cutting PDMS into segments that match the size of the glass slide (Glass size is 1.5 cm × 1.5 cm), adhering them to the glass slide, subjecting them to ultraviolet ozone plasma treatment for 10-20 min, then transferring them to a glove box and immersing them in isopropanol (IPA) for 15-25 min to obtain the product.
[0010] Preferably, in step (2), the D18:L8-BO solution is prepared by dissolving D18:L8-BO in chloroform at a mass ratio of (0.5-1):1.2 in a glove box to prepare a mixed solution with a concentration of 6-10 mg / mL.
[0011] Preferably, in step (3), the PBQx-TCl:PYIT solution is prepared by adding chloroform to the PBQx-TCl:PYIT solid in a glove box to prepare a PBQx-TCl:PYIT solution with a concentration of 2-6 mg / mL; the mass ratio of PBQx-TCl to PYIT is 1:1-1.2.
[0012] Preferably, in step (5), the vapor deposition thickness of the MoO3 is 1-3 nm; the vapor deposition thickness of the silver electrode is 90-110 nm.
[0013] The present invention also provides an inverted organic solar cell prepared by the above-described method for preparing a high-efficiency inverted organic solar cell with a dual heterojunction.
[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses D18:L8-BO and PBQx-TCl:PYIT as the donor and acceptor material system. By optimizing the solution concentration and film thickness of the D18:L8-BO layer and the PBQx-TCl:PYIT layer, a Glass / ITO / ZnO / PC structure is obtained by lamination process. 61 The BM / D18:L8-BO / PBQx-TCl:PYIT / MoO3 / Ag double heterojunction inverted organic solar cell device features a wide-spectrum response double heterojunction that achieves excellent short-circuit current density and high device performance while maintaining an excellent fill factor, ultimately achieving a photoelectric conversion efficiency of up to 20.27%.
[0015] 2. The PC in this invention 61 The BM layer is located on the ZnO surface. Its function is to modify and reduce the interfacial work function, improve the surface energy compatibility with the upper active layer, thereby reducing the electron extraction barrier and reducing the interfacial resistance. The combination of the two-body heterojunction layers D18:L8-BO and PBQx-TCl:PYIT serves as the main region for light absorption and exciton generation, which can effectively improve the photon capture rate. Moreover, its energy level matches the MoO3 hole transport layer, which can optimize the hole extraction path and prevent electrons from transporting to the anode. Attached Figure Description
[0016] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1This is a diagram illustrating the preparation process of the basic materials and the two-body heterojunction of this invention. Figure 2 This is a performance comparison chart of the device of the present invention; Figure 3 These are microscopic morphology diagrams of the single-layer and double-layer active layers of the present invention; Figure 4 This is a test graph showing the stability and thermal cycling stability curves of the single-layer and double-layer bulk heterojunction devices of the present invention. Detailed Implementation
[0018] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise defined, all technical terms used below have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in the present invention are commercially available or can be prepared by existing methods.
[0019] Example 1 The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction in this embodiment includes the following steps: (1) Preparation of the printing substrate structure: S1. ITO substrate pretreatment: The ITO substrate is ultrasonically cleaned sequentially with cleaning agent solution, deionized water, acetone, deionized water and isopropanol, with each step lasting 10 minutes, to obtain an ultrasonically cleaned ITO substrate; then the ultrasonically cleaned ITO substrate is dried with a nitrogen gun, and then placed in the chamber of an ultraviolet ozone cleaner for 25 minutes, and then taken out for use. S2. Preparation of Glass / ITO / ZnO: Spin-coating ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, annealing at 140℃ for 25 min on a constant temperature hot plate, and then transferring to a glove box (oxygen content <10 ppm; water content <0.1 ppm) to cool to room temperature to obtain Glass / ITO / ZnO; The ZnO solution was prepared as follows: 5 mmol of anhydrous zinc acetate was dissolved in 125 mL of methanol in a 500 mL beaker and heated to 60 °C. Then, potassium hydroxide methanol solution with a mass-to-volume ratio of 1 g:50 mL was slowly added dropwise and reacted for 15 min. Then, 1 mL of ethanolamine was added and the mixture was concentrated to 45 mL. Ethyl acetate was added to precipitate the product. The product was centrifuged and the supernatant was discarded. The precipitate was mixed with anhydrous ethanol and dissolved by sonication to obtain a ZnO solution with a concentration of 25 mg / mL. S3. Preparation of Glass / ITO / ZnO / PC 61BM: Inside the glove box, place the PC 61 BM was dissolved in chloroform to prepare PC with a concentration of 2 mg / mL. 61 BM solution; use a pipette to apply 15 μL of PC solution each time. 61 BM solution was spin-coated onto Glass / ITO / ZnO at 3500 rpm for 20 seconds to obtain Glass / ITO / ZnO / PC. 61 BM refers to the printing substrate structure. (2) Preparation of film-forming substrate structure one: Glass / PDMS was prepared by dissolving D18:L8-BO in chloroform at a mass ratio of 1:1.2 in a glove box to prepare a mixed solution with a concentration of 8 mg / mL. The D18:L8-BO solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds using a pipette, yielding Glass / PDMS / D18:L8-BO, which is the first film-forming substrate structure. The preparation method of Glass / PDMS is as follows: PDMS is cut into segments that match the size of the glass slide (Glass size is 1.5 cm × 1.5 cm), adhered to the glass slide, subjected to ultraviolet ozone plasma treatment for 10 min, then transferred to a glove box and immersed in isopropanol (IPA) for 15 min to obtain the product. (3) Preparation of film-forming substrate structure two: Glass / PDMS was prepared (as above); in a glove box, chloroform was added to PBQx-TCl:PYIT solid (PBQx-TCl to PYIT mass ratio of 1:1.2) to prepare a PBQx-TCl:PYIT solution with a concentration of 3 mg / mL; using a pipette, 15 μL of PBQx-TCl:PYIT solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds each time to obtain Glass / PDMS / PBQx-TCl:PYIT, which is the second film-forming substrate structure. (4) Laminated film substrate structure: Film-forming substrate structure one was placed over the printing substrate structure. After the D18:L8-BO film made firm contact with the printing substrate, the PDMS was removed. Film-forming substrate structure two was then placed over the D18:L8-BO film. After the PBQx-TCl:PYIT film made firm contact with the D18:L8-BO film, the PDMS was removed. The film was then annealed at 80°C for 5 minutes on a constant temperature hot plate to obtain Glass / ITO / ZnO / PC. 61BM / D18:L8-BO / PBQx-TCl:PYIT; the thickness ratio of the D18:L8-BO film to the PBQx-TCl:PYIT film is 80nm:35nm; (5) Evaporation of hole transport layer and electrode: Will Glass / ITO / ZnO / PC 61 BM / D18:L8-BO / PBQx-TCl:PYIT was used to sequentially deposit 1nm MoO3 and 90nm silver electrodes in a vacuum evaporation chamber, while controlling the chamber pressure to be <2×10⁻⁶. -5 Pa yields a structure of Glass / ITO / ZnO / PC. 61 Inverted organic solar cells of BM / D18:L8-BO / PBQx-TCl:PYIT / MoO3 / Ag.
[0020] Example 2 The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction in this embodiment includes the following steps: (1) Preparation of the printing substrate structure: S1. ITO substrate pretreatment: The ITO substrate is ultrasonically cleaned sequentially with cleaning agent solution, deionized water, acetone, deionized water and isopropanol, with each step lasting 20 minutes, to obtain an ultrasonically cleaned ITO substrate; then the ultrasonically cleaned ITO substrate is dried with a nitrogen gun, and then placed in the chamber of an ultraviolet ozone cleaner for 35 minutes, and then taken out for use. S2. Preparation of Glass / ITO / ZnO: Spin-coating ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, annealing at 160℃ for 15 min on a constant temperature hot plate, and then transferring to a glove box (oxygen content <10 ppm; water content <0.1 ppm) to cool to room temperature to obtain Glass / ITO / ZnO. The ZnO solution was prepared as follows: 15 mmol of anhydrous zinc acetate was dissolved in 125 mL of methanol in a 500 mL beaker and heated to 70 °C. Then, potassium hydroxide methanol solution with a mass-to-volume ratio of 1.1 g:50 mL was slowly added dropwise and reacted for 25 min. Then, 3 mL of ethanolamine was added and the mixture was concentrated to 55 mL. Ethyl acetate was added to precipitate the product. The product was centrifuged and the supernatant was discarded. The precipitate was mixed with anhydrous ethanol and dissolved by sonication to obtain a ZnO solution with a concentration of 35 mg / mL. S3. Preparation of Glass / ITO / ZnO / PC 61 BM: Inside the glove box, place the PC 61 BM was dissolved in chloroform to prepare PC with a concentration of 5 mg / mL. 61BM solution; use a pipette to apply 15 μL of PC solution each time. 61 BM solution was spin-coated onto Glass / ITO / ZnO at 3500 rpm for 20 seconds to obtain Glass / ITO / ZnO / PC. 61 BM refers to the printing substrate structure. (2) Preparation of film-forming substrate structure one: Glass / PDMS was prepared by dissolving D18:L8-BO in chloroform at a mass ratio of 1:1.2 in a glove box to prepare a mixed solution with a concentration of 8 mg / mL. The D18:L8-BO solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds using a pipette, yielding Glass / PDMS / D18:L8-BO, which is the first film-forming substrate structure. The preparation method of Glass / PDMS is as follows: PDMS is cut into segments that match the size of the glass slide (Glass size is 1.5 cm × 1.5 cm), adhered to the glass slide, and then subjected to ultraviolet ozone plasma treatment for 20 min. After that, it is transferred to a glove box and immersed in isopropanol (IPA) for 25 min to obtain the product. (3) Preparation of film-forming substrate structure two: Glass / PDMS was prepared (as above); in a glove box, chloroform was added to PBQx-TCl:PYIT solid (PBQx-TCl to PYIT mass ratio of 1:1.2) to prepare a PBQx-TCl:PYIT solution with a concentration of 5 mg / mL; using a pipette, 15 μL of PBQx-TCl:PYIT solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds each time to obtain Glass / PDMS / PBQx-TCl:PYIT, which is the second film-forming substrate structure. (4) Laminated film substrate structure: Film-forming substrate structure one was placed over the printing substrate structure. After the D18:L8-BO film made firm contact with the printing substrate, the PDMS was removed. Film-forming substrate structure two was then placed over the D18:L8-BO film. After the PBQx-TCl:PYIT film made firm contact with the D18:L8-BO film, the PDMS was removed. The film was then annealed at 80°C for 5 minutes on a constant temperature hot plate to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO / PBQx-TCl:PYIT; the thickness ratio of the D18:L8-BO film to the PBQx-TCl:PYIT film is 80nm:45nm; (5) Evaporation of hole transport layer and electrode: Will Glass / ITO / ZnO / PC 61 BM / D18:L8-BO / PBQx-TCl:PYIT was used to sequentially deposit 3 nm MoO3 and 110 nm silver electrodes in a vacuum evaporation chamber, while controlling the chamber pressure to be <2 × 10⁻⁶. -5 Pa yields a structure of Glass / ITO / ZnO / PC. 61 Inverted organic solar cells of BM / D18:L8-BO / PBQx-TCl:PYIT / MoO3 / Ag.
[0021] Example 3 The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction in this embodiment includes the following steps: (1) Preparation of the printing substrate structure: S1. ITO substrate pretreatment: The ITO substrate is ultrasonically cleaned sequentially with cleaning solution, deionized water, acetone, deionized water and isopropanol, with each step lasting 15 minutes, to obtain an ultrasonically cleaned ITO substrate; then the ultrasonically cleaned ITO substrate is dried with a nitrogen gun, and then placed in the chamber of an ultraviolet ozone cleaner for 30 minutes, and then taken out for use. S2. Preparation of Glass / ITO / ZnO: Spin-coating ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, annealing at 150℃ for 20 min on a constant temperature hot plate, and then transferring to a glove box (oxygen content <10 ppm; water content <0.1 ppm) to cool to room temperature to obtain Glass / ITO / ZnO; The ZnO solution was prepared as follows: 10 mmol of anhydrous zinc acetate was dissolved in 125 mL of methanol in a 500 mL beaker and heated to 65 °C. Then, potassium hydroxide methanol solution with a mass-to-volume ratio of 1.1 g:50 mL was slowly added dropwise and reacted for 20 min. Then, 2 mL of ethanolamine was added and the mixture was concentrated to 50 mL. Ethyl acetate was added to precipitate the product. The product was centrifuged and the supernatant was discarded. The precipitate was mixed with anhydrous ethanol and dissolved by sonication to obtain a ZnO solution with a concentration of 30 mg / mL. S3. Preparation of Glass / ITO / ZnO / PC 61 BM: Inside the glove box, place the PC 61 BM was dissolved in chloroform to prepare PC with a concentration of 3 mg / mL. 61 BM solution; use a pipette to apply 15 μL of PC solution each time. 61 BM solution was spin-coated onto Glass / ITO / ZnO at 3500 rpm for 20 seconds to obtain Glass / ITO / ZnO / PC. 61 BM refers to the printing substrate structure. (2) Preparation of film-forming substrate structure one: Glass / PDMS was prepared by dissolving D18:L8-BO in chloroform at a mass ratio of 0.9:1.2 in a glove box to prepare a mixed solution with a concentration of 8 mg / mL. The D18:L8-BO solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds using a pipette, yielding Glass / PDMS / D18:L8-BO, which is the first film-forming substrate structure. The preparation method of Glass / PDMS is as follows: PDMS is cut into segments that match the size of the glass slide (Glass size is 1.5 cm × 1.5 cm), adhered to the glass slide, and then subjected to ultraviolet ozone plasma treatment for 15 min. After that, it is transferred to a glove box and immersed in isopropanol (IPA) for 20 min to obtain the product. (3) Preparation of film-forming substrate structure two: Glass / PDMS was prepared as above; in a glove box, chloroform was added to PBQx-TCl:PYIT solid (PBQx-TCl to PYIT mass ratio of 1:1.2) to prepare a PBQx-TCl:PYIT solution with a concentration of 4 mg / mL; using a pipette, 15 μL of PBQx-TCl:PYIT solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds each time to obtain Glass / PDMS / PBQx-TCl:PYIT, which is the second film-forming substrate structure. (4) Laminated film substrate structure: Film-forming substrate structure one was placed over the printing substrate structure. After the D18:L8-BO film made firm contact with the printing substrate, the PDMS was removed. Film-forming substrate structure two was then placed over the D18:L8-BO film. After the PBQx-TCl:PYIT film made firm contact with the D18:L8-BO film, the PDMS was removed. The film was then annealed at 80°C for 5 minutes on a constant temperature hot plate to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO / PBQx-TCl:PYIT; the thickness ratio of the D18:L8-BO film to the PBQx-TCl:PYIT film is 80nm:30nm; (5) Evaporation of hole transport layer and electrode: Will Glass / ITO / ZnO / PC 61 BM / D18:L8-BO / PBQx-TCl:PYIT was used to sequentially deposit 2 nm MoO3 and 100 nm silver electrodes in a vacuum evaporation chamber, while controlling the chamber pressure to be <2 × 10⁻⁶. -5 Pa yields a structure of Glass / ITO / ZnO / PC.61 Inverted organic solar cells of BM / D18:L8-BO / PBQx-TCl:PYIT / MoO3 / Ag.
[0022] Example 4: The difference between this comparative solar cell and Example 2 is that the thickness of the D18:L8-BO film and the thickness of the PBQx-TCl:PYIT film are 80 / 50 nm.
[0023] Comparative Example 1: The difference between this comparative example solar cell and Example 3 is that the thickness of D18:L8-BO film / PBQx-TCl:PYIT film is 80 / 20nm.
[0024] Comparative Example 2: The difference between this comparative example solar cell and Example 3 is that the concentration of D18:L8-BO solution / PBQx-TCl:PYIT solution is 10 / 4 mg / ml; the thickness of D18:L8-BO film / PBQx-TCl:PYIT film is 110 / 30 nm.
[0025] Comparative Example 3: The difference between this comparative example solar cell and Example 3 is that the concentrations of D18:L8-BO solution / PBQx-TCl:PYIT solution are 6 / 4 mg / ml; and the thicknesses of D18:L8-BO film / PBQx-TCl:PYIT film are 60 / 30 nm.
[0026] Comparative Example 4: The difference between this comparative example solar cell and Example 3 is that the device has a single-layer structure: Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO / MoO3 / Ag.
[0027] Comparative Example 5: The difference between this comparative example solar cell and Example 3 is that the device has a single-layer structure: Glass / ITO / ZnO / PC. 61 BM / PBQx-TCl:PYIT / MoO3 / Ag.
[0028] The photovoltaic parameters of the solar cells prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were tested respectively, and the results are shown in Table 1. Under AM 1.5G simulated conditions, the parameters of the current-voltage characteristic curves of single-layer or double-layer bulk heterojunctions, and the irradiance (100 mW / cm²) are also shown. -2 The mean and standard deviation (in parentheses) are from 20 independent devices.
[0029] Table 1 Comparison of photovoltaic parameters for each group of devices Note: The existing double-layer structure is derived from the literature: Adv. Mater. 2023, 35, 2208997 As can be seen from the data in Examples 1 to 4 in Table 1, the present invention uses D18:L8-BO and PBQx-TCl:PYIT as the donor and acceptor material system, optimizes the thickness and concentration of the D18:L8-BO layer and PBQx-TCl:PYIT layer, and constructs a double heterojunction inverted organic solar cell device with a wide spectral response through a lamination process. This device achieves excellent short-circuit current density and high device performance while maintaining an excellent fill factor, and finally achieves a conversion efficiency of about 20.27%.
[0030] As can be seen from the data of Example 3 and Comparative Examples 1 to 3, the concentration and thickness of D18:L8-BO and PBQx-TCl:PYIT affect the photoelectric conversion efficiency. The concentration and thickness set by the present invention can effectively improve the photon capture rate, thereby generating a high output photocurrent for the device.
[0031] As can be seen from the data of Example 3 and Comparative Examples 4 and 5, compared with the single-layer structure, the multilayer stacked organic solar cell prepared by the present invention using laminated thin film can achieve a higher conversion efficiency.
[0032] As can be seen from the performance data of the bilayer structure device disclosed in Example 3 and the prior art (Comparative Example 6), the present invention optimizes the acceptor material system and optimizes the thickness and concentration of each layer, which can achieve a more efficient conversion efficiency.
[0033] Figure 1 This diagram illustrates the basic materials and fabrication process of the bilayer heterojunction of this invention, where: a) the chemical structures of D18, L8-BO, PBQx-TCl, and PYIT; b) a flowchart of the fabrication process of the bilayer BHJ device using laminated thin films; c) the interfacial adhesion energies of the D18:L8-BO and PBQx-TCl:PYIT blends on different substrates; d) the ultraviolet absorption spectra of D18, PBQx-TCl, L8-BO, and PYIT; and e) the depth-dependent optical absorption spectrum (FLAS) of the bilayer BHJ device in the vertical direction. Figure 1 It can be seen that all the chemical structural formulas and preparation processes of the dual-body heterostructure demonstrate the transferability of each active layer material. The interfacial adhesion energy of D18:L8-BO and PBQx-TCl:PYIT on different substrates confirms that the active layers can be successfully transferred.
[0034] Figure 2The diagram shows a performance comparison of the devices of this invention, where: a) the device structure of the bilayer bulk heterojunction organic solar cell; b) a schematic diagram of the carrier transport process in the bulk heterojunction thin film; c) the energy level diagram of the active layer material; d) the current-voltage characteristic curves of the monolayer (PBQx-TCl: PYIT, D18: L8-BO) and the bilayer bulk heterojunction; e) the statistical distribution histogram of multiple current-voltage data points; f) the external quantum efficiency (EQE) spectra of the monolayer and bilayer bulk heterojunctions; g) the performance of inverted organic solar cells reported in the literature and this work (marked with an asterisk); h) the charge extraction and recombination curves of the monolayer and bilayer bulk heterojunction devices at different delay times (the solid line is the dispersive bimolecular recombination fitting curve). Figure 2 It can be seen that the dual-body heterojunction device has a higher short-circuit current density and a better fill factor than the single-layer active layer device, ultimately achieving a conversion efficiency of about 20.27%.
[0035] Figure 3 The images show the microstructures of the single-layer and double-layer active layers of this invention; wherein: ac) scanning electron microscope (SEM) images of the layered single-layer and double-layer bulk heterojunctions, showing the layered structures of PBQx-TCl:PYIT, D18:L8-BO, and double-layer, respectively; df) two-dimensional grazing-incidence wide-angle X-ray scattering (GIWAXS) patterns of the single-layer and double-layer bulk heterojunction structures; g) in-plane (IP) and out-of-plane (OOP) crystal coherence lengths of different device structures; h) in-plane (IP) and out-of-plane (OOP) extracted wire-cut profiles of different device structures; from Figure 3 It is known that the transfer printing method for laminated films forms a clear interface between stacked multilayer films, preventing the same solvent from eroding the underlying layer during continuous film formation. This method maximizes the integrity of the active film layer.
[0036] Figure 4 This is a test graph showing the stability and thermal cycling stability curves of the single-layer and double-layer bulk heterojunction devices of the present invention. From... Figure 4 It can be seen that bilayer heterojunctions have better storage stability and thermal cycling stability than single-layer active layers.
[0037] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.
Claims
1. A method for fabricating a high-efficiency inverted organic solar cell with a dual-body heterojunction, characterized in that, Includes the following steps: (1) Preparation of the printing substrate structure: S1. ITO substrate pretreatment: The ITO substrate is ultrasonically cleaned and dried for later use; S2. Preparation of Glass / ITO / ZnO: Spin-coat ZnO solution onto Glass / ITO, anneal, and then transfer to a glove box to cool to room temperature to obtain Glass / ITO / ZnO. S3. Preparation of Glass / ITO / ZnO / PC 61 BM: PC 61 BM solution was spin-coated onto Glass / ITO / ZnO to obtain Glass / ITO / ZnO / PC. 61 BM refers to the printing substrate structure. (2) Preparation of film-forming substrate structure one: Glass / PDMS was prepared by spin-coating a D18:L8-BO solution onto Glass / PDMS to obtain Glass / PDMS / D18:L8-BO, which is the first film-forming substrate structure. (3) Preparation of film-forming substrate structure two: Glass / PDMS was prepared by spin-coating PBQx-TCl:PYIT solution onto Glass / PDMS to obtain Glass / PDMS / PBQx-TCl:PYIT, which is the second film-forming substrate structure. (4) Laminated film substrate structure: The first film-forming substrate structure is placed over the printing substrate structure. After the D18:L8-BO film makes firm contact with the printing substrate, the PDMS is removed. The second film-forming substrate structure is then placed over the D18:L8-BO film. After the PBQx-TCl:PYIT film makes firm contact with the D18:L8-BO film, the PDMS is removed, and the film is annealed to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO / PBQx-TCl:PYIT; the thickness ratio of the D18:L8-BO film to the PBQx-TCl:PYIT film is 80nm:(30-50)nm; (5) Evaporation of hole transport layer and electrode: The Glass / ITO / ZnO / PC 61 MoO3 and silver electrodes were sequentially deposited in a vacuum evaporation chamber using BM / D18:L8-BO / PBQx-TCl:PYIT, while controlling the chamber pressure to be <2×10⁻⁶. -5 Pa yields a structure of Glass / ITO / ZnO / PC. 61 Inverted organic solar cells of BM / D18:L8-BO / PBQx-TCl:PYIT / MoO3 / Ag.
2. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In step (1) S1, the ITO substrate pretreatment involves sequentially using a cleaning agent solution, deionized water, acetone, deionized water, and isopropanol to perform ultrasonic cleaning on the ITO substrate, with each step lasting 10-20 minutes, to obtain an ultrasonically cleaned ITO substrate; then, the ultrasonically cleaned ITO substrate is dried using a nitrogen gun, and then placed in the ultraviolet ozone cleaning machine chamber for 25-35 minutes, and then taken out for use.
3. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In step (1) S2, the ZnO solution is prepared as follows: In a 500 mL beaker, 5-15 mmol of anhydrous zinc acetate is dissolved in 125 mL of methanol and heated to 60-70 °C. Then, potassium hydroxide methanol solution with a mass-to-volume ratio of (1-1.1) g:50 mL is slowly added dropwise. The reaction is carried out for 15-25 min. Then, 1-3 mL of ethanolamine is added. The mixture is then concentrated to a volume of 45-55 mL. Ethyl acetate is added to precipitate the product. The product is centrifuged, the supernatant is discarded, and the precipitate is mixed with anhydrous ethanol and dissolved by ultrasonic treatment to obtain a ZnO solution with a concentration of 25-35 mg / mL.
4. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In step (1) S2, the annealing is performed at 140-160°C for 15-25 minutes on a constant temperature hot plate.
5. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 2, characterized in that, In step (1) S3, the PC 61 The preparation method of BM solution is as follows: In a glove box, PC... 61 BM was dissolved in chloroform to prepare PC with a concentration of 2-5 mg / mL. 61 BM solution.
6. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In steps (2) and (3), the Glass / PDMS is prepared by cutting PDMS into segments that match the size of the glass slide, adhering them to the glass slide, subjecting them to 10-20 min of ultraviolet ozone plasma treatment, then transferring them to a glove box and immersing them in isopropanol for 15-25 min to obtain the product.
7. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In step (2), the D18:L8-BO solution is prepared by dissolving D18:L8-BO in chloroform at a mass ratio of (0.5-1):1.2 in a glove box to prepare a mixed solution with a concentration of 6-10 mg / mL.
8. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In step (3), the PBQx-TCl:PYIT solution is prepared by adding chloroform to the PBQx-TCl:PYIT solid in a glove box to prepare a PBQx-TCl:PYIT solution with a concentration of 2-6 mg / mL; the mass ratio of PBQx-TCl to PYIT is 1:1-1.
2.
9. The method for fabricating a high-efficiency inverted organic solar cell with a dual heterojunction according to claim 1, characterized in that, In step (5), the vapor deposition thickness of the MoO3 is 1-3 nm; the vapor deposition thickness of the silver electrode is 90-110 nm.
10. An inverted organic solar cell prepared by the method of preparing a dual heterojunction high-efficiency inverted organic solar cell as described in any one of claims 1-9.