An inverted organic solar cell based on printing substrate modification and a preparation method thereof

Abstract

This invention discloses an inverted organic solar cell based on a substrate-modified substrate and its fabrication method, relating to the field of solar cell technology. This invention utilizes the fullerene derivative PC... 61 BM is used to modify the printing substrate, and D18:L8-BO is selected as the active layer. The active layer D18:L8-BO is laminated onto the PC. 61 The printing substrate modified with BM was used to construct a structure of Glass / ITO / ZnO / PC. 61 The inverted organic solar cell BM / D18:L8-BO / MoO3 / Ag achieved a photoelectric conversion efficiency of up to 19.32%.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to an inverted organic solar cell based on substrate modification and its preparation method. Background Technology

[0002] Organic solar cells have attracted widespread research interest due to their lightweight, solution processability, tunable spectral properties, and potential flexibility. Lamination transfer technology, which forms a thin film on one substrate and then transfers it to a target substrate, avoids special substrate requirements, making it a potential candidate technology for future commercial applications. However, traditional lamination transfer printing methods have failed to address issues such as interfacial contact and energy level mismatch between the transfer film and the printed substrate, resulting in incomplete films, difficulty in obtaining complete transfer films and efficient charge extraction, and consequently, suboptimal device performance. Summary of the Invention

[0003] To address the above shortcomings, this invention provides an inverted organic solar cell based on substrate modification 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 an inverted organic solar cell based on substrate modification includes the following steps: (1) Modification of the substrate: The ITO substrate was pretreated; ZnO solution was spin-coated onto Glass / ITO, annealed, and then transferred to a glove box to cool to room temperature to obtain Glass / ITO / ZnO; PC was prepared. 61 BM solution; PC 61 BM solution was spin-coated onto the Glass / ITO / ZnO to obtain Glass / ITO / ZnO / PC. 61 BM stands for PC 61 BM-modified printing substrate; (2) Lamination of film substrate: D18:L8-BO solution and Glass / PDMS were prepared; D18:L8-BO solution was spin-coated onto Glass / PDMS to obtain Glass / PDMS / D18:L8-BO, which is the film substrate; the film substrate was then coated onto the PC. 61 Above the BM-modified substrate, the D18:L8-BO film is to be laminated with PC. 61 After the BM-modified substrate has a tight contact, PDMS is removed, followed by annealing to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO; (3) Deposition of hole transport layer and electrode: The Glass / ITO / ZnO / PC is deposited. 61BM / D18:L8-BO was used to sequentially deposit MoO3 and 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 BM / D18:L8-BO / MoO3 / Ag-based inverted organic solar cells modified with printed substrate.

[0004] Preferably, in step (1), the pretreatment method of the ITO substrate is as follows: the ITO substrate is ultrasonically cleaned sequentially with cleaning agent solution, deionized water, acetone, deionized water and isopropanol, with each step lasting 10-20 min, 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 25-35 min, and then taken out for use.

[0005] Preferably, in step (1), 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.

[0006] Preferably, in step (1), the annealing is performed at 140-160°C on a constant temperature hot plate for 15-25 minutes.

[0007] Preferably, in step (1), 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.

[0008] Preferably, in step (2), the D18:L8-BO solution is prepared by dissolving D18:L8-BO in chloroform at a mass ratio of (0.8-1.2):1.2 in a glove box to prepare a mixed solution with a concentration of 6-10 mg / mL.

[0009] Preferably, in step (2), 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.

[0010] Preferably, in step (3), the vapor deposition thickness of the MoO3 is 1-3 nm; the vapor deposition thickness of the silver electrode is 90-110 nm.

[0011] The present invention also provides an inverted organic solar cell prepared by the method for preparing an inverted organic solar cell based on substrate modification.

[0012] Compared with the prior art, the beneficial effects of the present invention are: This invention uses fullerene derivative PC 61 BM is used to modify the printing substrate, and D18:L8-BO is selected as the active layer. The active layer D18:L8-BO is laminated onto the PC substrate. 61 The printing substrate modified with BM was used to construct a structure of Glass / ITO / ZnO / PC. 61 An inverted organic solar cell based on BM / D18:L8-BO / MoO3 / Ag achieved a photoelectric conversion efficiency as high as 19.32%. This was achieved using a fullerene derivative, PC. 61 Modifying the zinc oxide layer of the substrate with BM can increase the interfacial adhesion energy, significantly improve the contact between the D18:L8-BO active layer and the target substrate, and thus significantly enhance the integrity and uniformity of the laminated film, the charge extraction capability of the layered structure, and the suppression of bimolecular recombination. Combined with the active layer D18:L8-BO, this results in a significant improvement in photoelectric conversion efficiency, demonstrating the enormous potential of laminated thin-film optoelectronic device fabrication. It provides an alternative to traditional solution processing techniques and paves the way for advanced printing technology for organic solar cells. (See attached figures.) 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.

[0013] Figure 1 Chemical structural formulas and contact angle test diagrams of acceptor materials and fullerene derivatives; Figure 2 The device performance test diagrams are for devices obtained using lamination and spin coating methods. Figure 3 The images show the morphology of the films obtained by lamination and spin coating methods. Figure 4 The graph shows the stability test curves of devices fabricated using lamination and spin coating methods. Detailed Implementation

[0014] 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.

[0015] Example 1 This embodiment discloses a method for fabricating an inverted organic solar cell based on substrate modification, comprising the following steps: (1) Modify the printing substrate: ① Pretreatment of ITO substrate: The ITO substrate is ultrasonically cleaned sequentially with cleaning solution, deionized water, acetone, deionized water and isopropanol, each step lasting 10 min, to obtain ultrasonically cleaned ITO substrate; then the ultrasonically cleaned ITO substrate is dried with nitrogen gun and then placed in the chamber of ultraviolet ozone cleaner for 25 min to obtain Glass / ITO for later use. ② Preparation of ZnO solution: In a 500 mL beaker, 5 mmol of anhydrous zinc acetate was dissolved in 125 mL of methanol 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. The reaction was allowed to proceed for 15 min. Then, 1 mL of ethanolamine was added. The mixture was then 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. ③ In air, spin-coat the ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, anneal at 140℃ for 25 min on a constant temperature hot plate, and then transfer to a glove box to cool to room temperature (oxygen content <10 ppm; water content <0.1 ppm) to obtain Glass / ITO / ZnO; ④ Preparation of PC 61 BM solution: In the glove box, place PC 61 BM was dissolved in chloroform to prepare PC with a concentration of 2 mg / mL. 61 BM solution; ⑤ Use a pipette to apply 15 μL of PC at 3500 rpm for 20 seconds each time. 61 BM solution was spin-coated onto the Glass / ITO / ZnO to obtain Glass / ITO / ZnO / PC. 61 BM stands for PC 61 BM-modified printing substrate; (2) Laminated film substrate: ① Preparation of D18:L8-BO solution: In a glove box, dissolve D18:L8-BO in chloroform at a mass ratio of 1:1.2 to prepare a D18:L8-BO solution with a concentration of 10 mg / mL; ② Preparation of Glass / PDMS: PDMS (Polydimethylsiloxane) was cut into fragments (1.5 cm × 1.5 cm) that matched the size of the glass slide, adhered to the glass slide, and then subjected to ultraviolet ozone plasma treatment for 10 min. After that, it was transferred to a glove box and immersed in isopropanol for 15 min to obtain Glass / PDMS. ③ Preparation of film-forming substrate: Using a pipette, 15 μL of D18:L8-BO solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds each time to obtain Glass / PDMS / D18:L8-BO, which is the film-forming substrate; ④ Cover the PC obtained in step (1) with the film-forming substrate. 61 Above the BM-modified substrate, the D18:L8-BO film is to be laminated with PC. 61 After the BM-modified substrate has a tight contact, PDMS is removed, followed by annealing to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO; (3) Deposition of hole transport layer and electrode: The Glass / ITO / ZnO / PC is deposited. 61 BM / D18:L8-BO was used to sequentially deposit 1 nm MoO3 and 90 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 BM / D18:L8-BO / MoO3 / Ag-based inverted organic solar cells modified with printed substrate.

[0016] Example 2 This embodiment discloses a method for fabricating an inverted organic solar cell based on substrate modification, comprising the following steps: (1) Modify the printing substrate: ① Pretreatment of ITO substrate: The ITO substrate is ultrasonically cleaned sequentially with cleaning agent solution, deionized water, acetone, deionized water and isopropanol, each step lasting 20 min, to obtain ultrasonically cleaned ITO substrate; then the ultrasonically cleaned ITO substrate is dried with nitrogen gun and then placed in the chamber of ultraviolet ozone cleaner for 35 min to obtain Glass / ITO for later use. ② Preparation of ZnO solution: In a 500 mL beaker, 15 mmol of anhydrous zinc acetate was dissolved in 125 mL of methanol 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. The reaction was allowed to proceed for 25 min. Then, 3 mL of ethanolamine was added. The mixture was then 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. ③ In air, spin-coat the ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, anneal at 160℃ for 15 min on a constant temperature hot plate, and then transfer to a glove box to cool to room temperature (oxygen content <10 ppm; water content <0.1 ppm) to obtain Glass / ITO / ZnO; ④ Preparation of PC 61 BM solution: In the glove box, place PC 61 BM was dissolved in chloroform to prepare PC with a concentration of 5 mg / mL. 61 BM solution; ⑤ Use a pipette to apply 15 μL of PC at 3500 rpm for 20 seconds each time. 61 BM solution was spin-coated onto the Glass / ITO / ZnO to obtain Glass / ITO / ZnO / PC. 61 BM stands for PC 61 BM-modified printing substrate; (2) Laminated film substrate: ① Preparation of D18:L8-BO solution: In a glove box, dissolve D18:L8-BO in chloroform at a mass ratio of 1:1.2 to prepare a D18:L8-BO solution with a concentration of 6 mg / mL. ② Preparation of Glass / PDMS: PDMS (Polydimethylsiloxane) was cut into fragments (1.5 cm × 1.5 cm) that matched the size of the glass slide, adhered to the glass slide, and then subjected to ultraviolet ozone plasma treatment for 20 min. After that, it was transferred to a glove box and immersed in isopropanol for 25 min to obtain Glass / PDMS. ③ Preparation of film-forming substrate: Using a pipette, 15 μL of D18:L8-BO solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds each time to obtain Glass / PDMS / D18:L8-BO, which is the film-forming substrate; ④ Cover the PC obtained in step (1) with the film-forming substrate. 61 Above the BM-modified substrate, the D18:L8-BO film is to be laminated with PC. 61After the BM-modified substrate has a tight contact, PDMS is removed, followed by annealing to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO; (3) Deposition of hole transport layer and electrode: The Glass / ITO / ZnO / PC is deposited. 61 BM / D18:L8-BO 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 BM / D18:L8-BO / MoO3 / Ag-based inverted organic solar cells modified with printed substrate.

[0017] Example 3 This embodiment discloses a method for fabricating an inverted organic solar cell based on substrate modification, comprising the following steps: (1) Modify the printing substrate: ① Pretreatment of ITO substrate: The ITO substrate is ultrasonically cleaned sequentially with cleaning solution, deionized water, acetone, deionized water and isopropanol, each step lasting 15 minutes, to obtain ultrasonically cleaned ITO substrate; then the ultrasonically cleaned ITO substrate is dried with nitrogen gun and then placed in the chamber of ultraviolet ozone cleaner for 30 minutes to obtain Glass / ITO for later use. ② Preparation of ZnO solution: In a 500 mL beaker, 10 mmol of anhydrous zinc acetate was dissolved in 125 mL of methanol and heated to 60 °C. Then, potassium hydroxide methanol solution with a mass-to-volume ratio of 1.1 g:50 mL was slowly added dropwise. The reaction was allowed to proceed for 20 min. Then, 1 mL of ethanolamine was added. The mixture was then 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. ③ In air, spin-coat the ZnO solution onto Glass / ITO at 4000 rpm for 20 seconds, anneal at 150°C for 20 min on a constant temperature hot plate, and then transfer to a glove box (oxygen content <10 ppm; water content <0.1 ppm) to cool to room temperature to obtain Glass / ITO / ZnO; ④ Preparation of PC 61 BM solution: In the glove box, place PC 61 BM was dissolved in chloroform to prepare PC with a concentration of 2-5 mg / mL. 61 BM solution; ⑤ Use a pipette to apply 15 μL of PC at 3500 rpm for 20 seconds each time. 61BM solution was spin-coated onto the Glass / ITO / ZnO to obtain Glass / ITO / ZnO / PC. 61 BM stands for PC 61 BM-modified printing substrate; (2) Laminated film substrate: ① Preparation of D18:L8-BO solution: In a glove box, dissolve D18:L8-BO in chloroform at a mass ratio of 1:1.2 to prepare a D18:L8-BO solution with a concentration of 8 mg / mL. ② Preparation of Glass / PDMS: PDMS (Polydimethylsiloxane) was cut into fragments (1.5 cm × 1.5 cm) that matched the size of the glass slide, adhered to the glass slide, and then subjected to ultraviolet ozone plasma treatment for 15 min. After that, it was transferred to a glove box and immersed in isopropanol for 20 min to obtain Glass / PDMS. ③ Preparation of film-forming substrate: Using a pipette, 15 μL of D18:L8-BO solution was spin-coated onto Glass / PDMS at 3500 rpm for 20 seconds each time to obtain Glass / PDMS / D18:L8-BO, which is the film-forming substrate; ④ Cover the PC obtained in step (1) with the film-forming substrate. 61 Above the BM-modified substrate, the D18:L8-BO film is to be laminated with PC. 61 After the BM-modified substrate has a tight contact, PDMS is removed, followed by annealing to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO; (3) Deposition of hole transport layer and electrode: The Glass / ITO / ZnO / PC is deposited. 61 BM / D18:L8-BO was used to sequentially deposit 2nm MoO3 and 110nm 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 BM / D18:L8-BO / MoO3 / Ag-based inverted organic solar cells modified with printed substrate.

[0018] Comparative Example 1: The difference between this comparative example solar cell and Example 3 is that PC is not modified onto ZnO. 61 BM, with other steps the same as in Example 3, the resulting solar cell has the structure of Glass / ITO / ZnO / D18:L8-BO / MoO3 / Ag.

[0019] Comparative Example 2: The difference between this comparative example solar cell and Example 3 is that spin coating is used instead of lamination, i.e., on PC... 61 D18:L8-BO was spin-coated onto the BM-modified substrate, and other steps were the same as in Example 3. The resulting solar cell had a Glass / ITO / ZnO / PC structure. 61 BM / D18:L8-BO / MoO3 / Ag.

[0020] Comparative Example 3: The difference between this comparative example solar cell and Example 3 is that PC is not modified onto ZnO. 61 BM, and spin coating is used instead of lamination, that is, D18:L8-BO is directly spin-coated on the unmodified substrate. Other steps are the same as in Example 3. The structure of the solar cell is Glass / ITO / ZnO / D18:L8-BO / MoO3 / Ag.

[0021] Comparative Example 4: The difference between this comparative example solar cell and Example 3 is that C was used in its fabrication. 60 PC replacement 61 BM modifies the substrate, and the other steps are the same as in Example 3. The resulting solar cell has a structure of Glass / ITO / ZnO / C. 60 / D18:L8-BO / MoO3 / Ag.

[0022] Comparative Example 5: The difference between this comparative example solar cell and Example 3 is that PC was used in its fabrication. 71 BM replaces PC 61 BM modifies the substrate, and the other steps are the same as in Example 3. The resulting solar cell has a Glass / ITO / ZnO / PC structure. 71 BM / D18:L8-BO / MoO3 / Ag.

[0023] Comparative Example 6: The difference between this comparative example solar cell and Example 3 is that PM6 was used instead of D18. All other steps were the same as in Example 3. The resulting solar cell had a structure of Glass / ITO / ZnO / PC. 61 BM / PM6:L8-BO / MoO3 / Ag.

[0024] The photovoltaic parameters of the solar cells prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were tested respectively, and the results are shown in Table 1. Under AM 1.5G simulation 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 derived from the mean of 50 independent devices.

[0025] Table 1 Comparison of photovoltaic parameters for each group of devices As can be seen from the data in Examples 1 to 3 in Table 1, the present invention uses the fullerene derivative PC 61 BM is used to modify the printing substrate, and D18:L8-BO is selected as the active layer. The active layer D18:L8-BO is laminated onto the PC substrate. 61 The printing substrate modified with BM was used to construct a structure of Glass / ITO / ZnO / PC. 61 The inverted organic solar cell BM / D18:L8-BO / MoO3 / Ag achieved a photoelectric conversion efficiency of up to 19.32%.

[0026] As can be seen from the data of Example 3 and Comparative Example 1, compared with the unmodified product, the use of fullerene derivative PC... 61 Modifying the zinc oxide layer of the substrate with BM can improve the interfacial adhesion energy, thereby significantly enhancing the integrity, uniformity, and charge extraction capability of the laminated film, ultimately achieving a significant improvement in photoelectric conversion efficiency.

[0027] As can be seen from the data of Example 3 and Comparative Examples 2 and 3, compared with the spin coating method, the lamination method of the present invention can achieve a higher conversion efficiency.

[0028] As can be seen from the data of Example 3 and Comparative Examples 4 and 5, compared with C 60 PC 71 Compared to other modifiers such as BM, PC is preferred. 61 BM-modified substrates can achieve higher photoelectric conversion efficiency.

[0029] Data from Example 3 and Comparative Example 6 show that, compared to PM6:L8-BO as the active layer, using D18:L8-BO as the active layer provides better compatibility with PC. 61 BM-modified substrates enable higher photoelectric conversion efficiency.

[0030] Figure 1 The chemical structural formulas and contact angle test diagrams of the acceptor material and fullerene derivative are provided, where: a) PM6, D18, L8-BO, C60, PC 61 BM and PC 71 Chemical structures of BM. b) ZnO, ZnO / C60, ZnO / PC 61 BM and ZnO / PC 71 Contact angle of BM in water and formamide (FA). c) Image of transferred PM6:L8-BO film. From Figure 1 It can be seen that the ZnO layer is processed through the fullerene derivative PC. 61The modification of MB increases the interfacial adhesion, promoting complete transfer of PM6:L8-BO film.

[0031] Figure 2 The figures show device performance test patterns obtained using lamination and spin coating methods, where: a) ZnO / C, ZnO / L, ZnO / PC 61 BM / C and ZnO / PC 61 JV characteristic curves of BM / L; b) ZnO / C, ZnO / L, ZnO / PC 61 BM / C and ZnO / PC 61 c) External quantum efficiency (EQE) spectrum of ZnO / C, ZnO / L, and ZnO / PC; d) Surface photovoltage (SPV) measurement; e) Normalized transient photocurrent (TPC); f) Normalized transient photovoltage (TPV); f–i) Charge extraction and recombination curves of the device at different delay times, corresponding to ZnO / C, ZnO / L, and ZnO / PC. 61 BM / C and ZnO / PC 61 The structure of BM / L (solid line represents the fitted curve of dispersive bimolecular complex). From Figure 2 It can be seen that when fullerene derivative PC is coated on ZnO... 61 When BM is applied, the contact between the PM6:L8-BO active layer and the target substrate can be significantly improved, and charge extraction, trap state reduction and bimolecular recombination suppression can be successfully improved.

[0032] Note: "C" stands for spin-coating, indicating that the film is spin-coated onto ZnO or ZnO / PC. 61 On the BM substrate, "L" stands for lamination, indicating that the film is laminated on ZnO or ZnO / PC. 61 On BM substrate; ZnO / C, ZnO / PC 61 BM / C are used as ZnO / L and ZnO / PC, respectively. 61 The control group for BM / L. The difference between these two methods lies in the different film formation methods, and the same applies below.

[0033] Figure 3 Figure 1 shows the morphology of the films obtained by lamination and spin coating methods; where: a–d) represent films with ZnO / C, ZnO / L, and ZnO / PC, respectively. 61 BM / C and ZnO / PC 61 SEM images of PM6:L8-BO films with ZnO / C, ZnO / L, and ZnO / PC layer structures, respectively. (e–h) 61 BM / C and ZnO / PC 61Two-dimensional GIWAXS spectra of PM6:L8-BO films with BM / L layer structures. (i–l) represent ZnO / C, ZnO / L, and ZnO / PC structures, respectively. 61 BM / C and ZnO / PC 61 AFM images of PM6:L8-BO films with BM / L layer structures. m, n) represent the active PM6:L8-BO layers on ITO / ZnO and PDMS substrates, respectively, and the elemental content variations with depth; o, p) represent the vertical gradient distribution of N1s elemental content in the PM6:L8-BO film on different ITO / ZnO and PDMS substrates; from Figure 3 It can be seen that by morphological analysis of films obtained by different preparation methods to quantify the vertical compositional gradient of PM6:L8-BO films, the distribution pattern varies depending on the substrate. On ITO / ZnO substrates with higher surface energy, the acceptor material (L8-BO) is more significantly enriched at the bottom interface. Conversely, when the film is formed on a PDMS substrate with lower surface energy, the donor material (PM6) is enriched at the bottom, while the acceptor is concentrated at the air interface. Flipping the film during lamination, so that the acceptor is located at a new bottom interface, effectively improves the vertical gradient.

[0034] Figure 4 The figures show the stability test curves of devices fabricated using lamination and spin coating methods; where: a) the thermal cycling stability curve of PM6:L8-BO film and b) the stability curve of PM6:L8-BO film correspond to ZnO / C, ZnOL, and ZnO / PC, respectively. 61 BM / C and ZnO / PC 61 BM / L structure; JV characteristic curve of PM6:L8-BO: c) Area is 0.08cm² 2 The device; d) has an area of ​​0.04 cm². 2 The flexible ITO-PET device; e) the normalized PCE decay of the corresponding flexible device after different bending cycles; f) the JV characteristics of the D18:L8-BO film; and g) the external quantum efficiency (EQE) spectrum of the D18:L8-BO film, corresponding to ZnO / C, ZnO / L, and ZnO / PC films, respectively. 61 BM / C and ZnO / PC 61 BM / L structure; h)D18:L8-BO thin film ZnO / PC 61 Storage stability test curves for BM / L. From Figure 4 It can be seen that: after processing with the fullerene derivative PC 61 After BM modification, the laminated thin film device exhibits better storage stability and thermal cycling stability, achieving better mechanical stability of flexible devices.

[0035] In the figures above, we first used PM6:L8-BO as the active layer for electrical and morphological characterization tests, and then used the same preparation method to achieve the best performance in the D18:L8-BO layer.

[0036] 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 an inverted organic solar cell based on substrate modification, characterized in that, Includes the following steps: (1) Modify the substrate: Pre-treat the ITO substrate; spin-coat the ZnO solution onto Glass / ITO, anneal, and then transfer it to a glove box to cool to room temperature to obtain Glass / ITO / ZnO; Preparation of PC 61 BM solution; PC 61 BM solution was spin-coated onto the Glass / ITO / ZnO to obtain Glass / ITO / ZnO / PC. 61 BM stands for PC 61 BM-modified printing substrate; (2) Lamination of film substrate: D18:L8-BO solution and Glass / PDMS were prepared; D18:L8-BO solution was spin-coated onto Glass / PDMS to obtain Glass / PDMS / D18:L8-BO, which is the film substrate; the film substrate was then coated onto the PC. 61 Above the BM-modified substrate, the D18:L8-BO film is to be laminated with PC. 61 After the BM-modified substrate has a tight contact, PDMS is removed, followed by annealing to obtain Glass / ITO / ZnO / PC. 61 BM / D18:L8-BO; (3) Deposition of hole transport layer and electrode: The Glass / ITO / ZnO / PC is deposited. 61 BM / D18:L8-BO was used to sequentially deposit MoO3 and 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 BM / D18:L8-BO / MoO3 / Ag-based inverted organic solar cells modified with printed substrate.

2. The method for fabricating an inverted organic solar cell based on substrate modification according to claim 1, characterized in that, In step (1), the pretreatment method of the ITO substrate is as follows: the ITO substrate is ultrasonically cleaned sequentially with cleaning agent solution, deionized water, acetone, deionized water and isopropanol, with each step lasting 10-20 min, 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 25-35 min, and then taken out for use.

3. The method for fabricating an inverted organic solar cell based on substrate modification according to claim 1, characterized in that, In step (1), 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 an inverted organic solar cell based on substrate modification according to claim 1, characterized in that, In step (1), the annealing is performed at 140-160℃ on a constant temperature hot plate for 15-25 minutes.

5. The method for fabricating an inverted organic solar cell based on substrate modification according to claim 2, characterized in that, In step (1), 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 at a concentration of 2-5 mg / mL. 61 BM solution.

6. The method for fabricating an inverted organic solar cell based on substrate modification 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 (0.8-1.2):1.2 in a glove box to prepare a mixed solution with a concentration of 6-10 mg / mL.

7. The method for fabricating an inverted organic solar cell based on substrate modification according to claim 1, characterized in that, In step (2), 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.

8. The method for fabricating an inverted organic solar cell based on substrate modification according to claim 1, characterized in that, In step (3), the vapor deposition thickness of the MoO3 is 1-3 nm; the vapor deposition thickness of the silver electrode is 90-110 nm.

9. An inverted organic solar cell prepared by the method of fabricating an inverted organic solar cell based on substrate modification as described in any one of claims 1-8.

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