A fully perovskite tandem solar cell based on a smart self-healing tunneling layer and its fabrication method

Abstract

This invention discloses an all-perovskite tandem solar cell based on a smart self-healing tunneling layer and its fabrication method. The solar cell comprises, from bottom to top, a conductive substrate, a wide-bandgap perovskite solar cell, a smart self-healing tunneling layer, a narrow-bandgap perovskite solar cell, and an interface top electrode. The tunneling layer comprises a first layer of disulfide-bonded polyurethane with dispersed silver nanoparticles, an intermediate layer of hydrogen-bonded polyamide with dispersed indium tin oxide nanoparticles, and a third layer of ionicly cross-linked polyvinyl alcohol with dispersed gold nanoparticles. The fabrication method includes sequentially fabricating the wide-bandgap perovskite solar cell, the smart self-healing tunneling layer, the narrow-bandgap perovskite solar cell, and the interface top electrode on the conductive substrate. This invention repairs defects in the perovskite layer through the smart self-healing tunneling layer, enabling rapid response and maintaining consistently high charge transport performance, thus improving the performance of the all-perovskite tandem solar cell.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device technology and relates to an all-perovskite tandem solar cell based on an intelligent self-healing tunneling layer and its preparation method. Background Technology

[0002] Photovoltaic (PV) technology is considered one of the most promising low-cost alternatives to traditional fossil fuels. Crystalline silicon (c-Si) solar cells currently dominate the commercial PV market due to their mature processes, excellent reliability, and abundant raw materials. However, the efficiency of existing c-Si cells is approaching its practical efficiency limit. To further reduce the cost of photovoltaic power generation, more cost-effective photovoltaic technologies must be developed to further improve the power conversion efficiency (PCE) of cells and modules. Multi-junction solar cells, by stacking solar cells with different band gaps, allow each cell to more effectively utilize different parts of the solar spectrum and reduce thermal losses, potentially improving PCE and breaking the Shockley-Queisser limit of single-junction solar cells. However, manufacturing a compact and efficient tunneling layer presents technical challenges.

[0003] Currently, methods for preparing tunneling layers include sputtering indium tin oxide (ITO) as the tunneling layer and using atomic deposition (ALD) SnO. x As a buffer layer, it protects the underlying devices from sputtering damage. Thermally evaporated MoO2 can also be used. x As a buffer layer, it prevents damage to the copper bath (BCP) / Ag layer during ITO sputtering and ensures good contact between Ag and ITO. To prevent solvent penetration into the top cell during bottom cell processing, the typical ITO thickness exceeds 100 nm. Furthermore, a 5 nm aluminum-doped zinc oxide (AZO) layer deposited by solution treatment of the polyethyleneimine (PEIE) layer is sufficient to protect the bottom cell from solution treatment. However, cells fabricated using these methods struggle to maintain stable photovoltaic output over long periods and are susceptible to changes in external factors such as light and temperature. Damage or defects caused by these environmental changes significantly impact cell lifespan. Therefore, a simpler and more effective combination strategy is needed to overcome these problems and fabricate a more stable tunneling layer to improve the photovoltaic performance of all-perovskite solar cells. Summary of the Invention

[0004] To address the technical problems of short lifespan, poor stability, and slow response in existing perovskite tandem solar cells, this invention provides a fully perovskite tandem solar cell based on an intelligent self-healing tunneling layer and its fabrication method. The technical solution adopted in this invention is as follows:

[0005] A smart self-healing tunneling layer for an all-perovskite tandem solar cell includes: a first layer close to the upper perovskite layer, a third layer close to the lower perovskite layer, and an intermediate layer disposed between the first layer and the third layer.

[0006] The first layer consists of disulfide bond-based polyurethane with dispersed silver nanoparticles;

[0007] The intermediate layer is composed of hydrogen-bonded polyamide with indium tin oxide nanoparticles dispersed therein;

[0008] The third layer consists of polyvinyl alcohol with ionic crosslinking of dispersed gold nanoparticles.

[0009] A fully perovskite tandem solar cell based on a smart self-healing tunneling layer includes a conductive substrate, a wide-bandgap perovskite solar cell, a smart self-healing tunneling layer, a narrow-bandgap perovskite solar cell, and an interface top electrode stacked sequentially from bottom to top.

[0010] In one embodiment of the present invention, the wide-bandgap perovskite solar cell is arranged in layers from bottom to top: NiO x Or PTAA thin film hole transport layer, crystalline Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 Conductive active layer and PCBM thin film electron transport layer.

[0011] In one embodiment of the present invention, the narrow bandgap perovskite solar cell is arranged in the following layers from bottom to top: a PEDOT:PSS thin film hole transport layer, a crystalline FA layer, and so on. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 conductive active layer and C60 and BCP electron transport layer.

[0012] In one embodiment of the present invention, the conductive substrate is made of ITO or FTO conductive glass; the interface top electrode is made of Ag.

[0013] A method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer includes the following steps:

[0014] S1: Fabrication of wide-bandgap perovskite solar cells on a conductive substrate;

[0015] S2: A three-layer intelligent self-healing tunneling layer is formed by sequentially spin-coating a mixed solution of polyvinyl alcohol with ionic crosslinking dispersed gold nanoparticles, a mixed solution of polyamide with hydrogen bonds dispersed indium tin oxide nanoparticles, and a mixed solution of polyurethane with dispersed silver nanoparticles onto the wide-bandgap perovskite solar cell.

[0016] S3: Fabricate a narrow bandgap perovskite solar cell on the intelligent self-healing tunneling layer;

[0017] S4: Fabricate an interface top electrode on the narrow bandgap perovskite solar cell.

[0018] In one embodiment of the present invention, S2 includes:

[0019] S21. Prepare the third layer of the intelligent self-healing tunneling layer:

[0020] Ionic cross-linked polyvinyl alcohol is dissolved in a solvent to prepare a solution with a concentration of 6-10 wt%.

[0021] Add gold nanoparticles at a concentration of 3-6 wt% and ultrasonically disperse for 25-40 minutes to obtain a mixed solution of polyvinyl alcohol with ionic crosslinking containing gold nanoparticles.

[0022] A mixed solution of polyvinyl alcohol with ionic crosslinking dispersed gold nanoparticles was spin-coated onto the surface of the wide-bandgap perovskite solar cell at a rotation speed of 1600~2000 rpm, a spin-coating time of 30~40 s, and a solution flow rate of 0.06~0.1 mL / s.

[0023] Annealing was performed under nitrogen protection at a temperature of 90-110°C for 8-12 minutes to obtain a crystalline third layer of film.

[0024] S22. Prepare the intermediate layer of the intelligent self-healing tunneling layer:

[0025] Hydrogen-bonded polyamides are dissolved in a solvent to prepare a solution with a concentration of 10-15 wt%.

[0026] Indium tin oxide nanoparticles were added at a concentration of 6-10 wt%, and the mixture was ultrasonically treated for 40-60 min to uniformly disperse the nanoparticles, thus obtaining a mixed solution of hydrogen-bonded polyamide and indium tin oxide nanoparticles.

[0027] A mixed solution of hydrogen-bonded polyamide and indium tin oxide nanoparticles was spin-coated onto the third layer at a rotation speed of 2000-2500 rpm, a spin-coating time of 40-50 s, and a solution flow rate of 0.1-0.15 mL / s.

[0028] Annealing was performed under nitrogen protection at a temperature of 110-130°C for 15-20 minutes to obtain a crystalline intermediate layer for thin films.

[0029] S23. Prepare the first layer of the intelligent self-healing tunneling layer:

[0030] Disulfide bond-based polyurethane is dissolved in a solvent to prepare a solution with a concentration of 8~12 wt%;

[0031] Silver nanoparticles were added, with the concentration of silver nanoparticles controlled at 4-8 wt%. The mixture was ultrasonically treated for 30-60 min to uniformly disperse the silver nanoparticles, thus obtaining a polyurethane mixed solution containing dispersed silver nanoparticles.

[0032] A mixed solution of polyurethane with dispersed silver nanoparticles was spin-coated onto the intermediate layer at a speed of 1800~2200 rpm for 30~40 s, with the solution flow rate controlled at 0.08~0.12 mL / s.

[0033] The material is placed in a tube furnace and annealed under a nitrogen atmosphere at a temperature of 80-100℃ for 10-15 minutes to obtain a first crystalline thin film.

[0034] S24. Overall processing:

[0035] The sample obtained in S23 was subjected to overall annealing or light treatment. The annealing temperature was 120~150℃ and the annealing time was 20~30 min. The light treatment was performed by irradiation with an ultraviolet lamp and a light intensity of 10~20 mW / cm². 2 The light exposure time is 1-2 hours.

[0036] In one embodiment of the present invention, S1 includes:

[0037] S11. Pre-treat the conductive substrate;

[0038] S12. Perform UV ozone treatment on the pretreated conductive substrate surface for 20-25 min, and spin-coat the UV ozone-treated conductive substrate surface with 10 mg / mL NiO. x Alternatively, annealing with a PTAA precursor solution at 120-150℃ for 20-30 min yields NiO with a thickness of 60-70 nm. x Or a PTAA thin-film hole transport layer;

[0039] S13, the NiO after stabilization x Alternatively, a wide-bandgap perovskite Cs film can be spin-coated onto the surface of a PTAA thin-film hole transport layer. 0.2 FA 0.8 PbI 1.8 Br 1.2 The precursor solution was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. At the 30th s mark, 200 μL of the antisolvent CB was added for extraction, followed by annealing at 100–110 °C for 10–15 min to obtain crystalline Cs with a thickness of 400–600 nm.0.2 FA 0.8 PbI 1.8 Br 1.2 Thin-film conductive active layer;

[0040] S14, in the crystallization of Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 A precursor suspension of PCBM material was spin-coated onto a thin-film conductive active layer. The PCBM concentration was 20 mg / ml, the spin speed was 4000 rpm, the time was 40 s, and a PCBM thin-film electron transport layer with a thickness of 70~80 nm was grown.

[0041] In one embodiment of the present invention, S3 includes:

[0042] S31. Spin-coat the precursor solution of PEDOT:PSS onto the first layer and anneal it at 100~120℃ for 10~15 min to obtain a hole transport layer of PEDOT:PSS film with a thickness of 60~80 nm.

[0043] S32. Spin-coat a narrow-bandgap perovskite FA onto the surface of the stabilized PEDOT:PSS thin film hole transport layer. 0.7 MA 0.3 Pb 0.5 Sn 0.5 The precursor solution of I3 was annealed to obtain crystalline FA with a thickness of 800~1000 nm. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 thin-film conductive active layer;

[0044] S33, in FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 On the conductive active layer of the I3 thin film, a C60 layer with a thickness of 10~20 nm and a BCP layer with a thickness of 5~10 nm are sequentially prepared by thermal evaporation, which are combined to form a C60 and BCP electron transport layer.

[0045] In one embodiment of the present invention, the thickness of the Ag material of the interface top electrode is 80~100 nm.

[0046] The beneficial effects of this invention are:

[0047] 1. The intelligent self-healing tunneling layer of the present invention has a rapid response capability. Once the battery suffers microscopic damage during operation, the self-healing mechanism can be activated and complete the repair process in a very short time (usually within a few minutes or even less), thereby effectively preventing the further expansion and deterioration of the defect.

[0048] 2. The all-perovskite tandem solar cell of the present invention uses self-healing polymer molecules combined with highly conductive nanoparticles as a tunneling layer. When subjected to external stimuli (such as light, temperature changes, mechanical stress, etc.), the self-healing polymer molecules can automatically fill and repair the microscopic defects and damage caused by various external factors through dynamic chemical bond recombination or molecular chain movement, thereby optimizing the interface performance. At the same time, the highly conductive nanoparticles are uniformly dispersed in the polymer matrix to ensure that the high-efficiency charge transport performance is maintained throughout the self-healing process.

[0049] 3. The method for preparing the all-perovskite tandem solar cell of the present invention is simpler, more efficient, and easier to mass-produce, which helps to promote the industrialization of perovskite solar cells. Attached Figure Description

[0050] Figure 1 A schematic diagram of the intelligent self-healing tunneling layer of the all-perovskite tandem solar cell provided in an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the structure of an all-perovskite tandem solar cell based on a smart self-healing tunneling layer provided in an embodiment of the present invention;

[0052] Figure 3 A flowchart illustrating the fabrication method of an all-perovskite tandem solar cell based on a smart self-healing tunneling layer, as provided in an embodiment of the present invention.

[0053] Figure 4 JV curve of the all-perovskite tandem solar cell provided in the embodiment of the present invention;

[0054] Figure 5 The image shows the XRD pattern of the all-perovskite tandem solar cell provided in the embodiment of the present invention.

[0055] 1. Conductive substrate; 2. Wide bandgap perovskite solar cell; 3. Intelligent self-healing tunneling layer; 31. First layer; 32. Middle layer; 33. Third layer; 4. Narrow bandgap perovskite solar cell; 5. Interface top electrode. Detailed Implementation

[0056] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0057] Example 1:

[0058] Embodiment 1 of the present invention provides a smart self-healing tunneling layer for an all-perovskite tandem solar cell, as shown in the attached figure. Figure 1 The intelligent self-healing tunneling layer comprises: a first layer 31 near the upper perovskite layer, a third layer 33 near the lower perovskite layer, and an intermediate layer 32 disposed between the first and third layers. The first layer 31 is composed of disulfide-bonded polyurethane with dispersed silver nanoparticles, the intermediate layer 32 is composed of hydrogen-bonded polyamide with dispersed indium tin oxide nanoparticles, and the third layer 33 is composed of ionicly cross-linked polyvinyl alcohol with dispersed gold nanoparticles.

[0059] The first layer, 31, has a thickness of 5–10 nm and is composed of disulfide-bonded polyurethane with dispersed silver nanoparticles (approximately 5–10 nm in diameter, with a uniform interparticle spacing of 1–2 nm). These disulfide bonds can rapidly recombine upon exposure to light or temperature changes, achieving self-repair. The silver nanoparticles are uniformly distributed within the polymer, forming a well-conducting network. This layer is primarily responsible for rapid response and repair of defects at the interface between the upper perovskite layer and the tunneling layer, facilitating efficient hole transport. Its relatively thin thickness reduces the charge transport distance, while the presence of silver nanoparticles enhances charge transport efficiency.

[0060] The intermediate layer 32 is a 10-15 nm thick composite layer of hydrogen-bonded polyamide and indium tin oxide nanoparticles (approximately 15-20 nm in diameter, with an interparticle spacing of approximately 2-3 nm). The hydrogen bonds in the polyamide can break and reform under appropriate conditions, aiding in the repair of potential damage. The high conductivity of the indium tin oxide nanoparticles enhances charge transport in this layer. This layer stabilizes charge transport and buffers the performance differences between the upper and lower layers.

[0061] The third layer, 33, is 5–10 nm thick and consists of ionicly cross-linked polyvinyl alcohol (PVA) and gold nanoparticles (approximately 8–12 nm in diameter with an interparticle spacing of 1–2 nm). The ionic bonds of the PVA can dynamically change under external stimuli to repair damage, while the gold nanoparticles provide efficient charge transport channels. This layer is primarily responsible for good contact and charge transport with the underlying perovskite layer and for repairing any defects that may occur in the underlying layer.

[0062] The self-healing principle of the intelligent self-healing tunneling layer in this invention is based on the reversible change of chemical bonds:

[0063] The first layer belongs to the disulfide bond system: taking polyurethane containing disulfide bonds as an example, the disulfide bond (-SS-) is thermally reversible. When the self-healing tunneling layer is subjected to external stimuli such as heat, light, or mechanical stress, the disulfide bond undergoes homolytic cleavage, forming two sulfur free radicals (-S·). These free radicals have high activity, allowing the polyurethane molecular chains to move and rearrange to a certain extent. When the molecular chains at the damaged site move to the appropriate position, the two sulfur free radicals can recombine to form a disulfide bond, thereby achieving self-healing of the material. For example, during the operation of perovskite solar cells, thermal stress caused by temperature changes may lead to microcracks in the tunneling layer. At this time, under appropriate thermal stimulation (generally 60~80°C), the disulfide bond breaks and recombines, filling the crack and restoring the continuity and performance of the material.

[0064] The first layer consists of disulfide-bonded polyurethane with dispersed silver nanoparticles, the middle layer consists of hydrogen-bonded polyamide with dispersed indium tin oxide nanoparticles, and the third layer consists of ionicly cross-linked polyvinyl alcohol with dispersed gold nanoparticles.

[0065] The middle layer belongs to a hydrogen-bonded system: In hydrogen-bonded polyamide materials, hydrogen bonds are a relatively weak but numerous intermolecular force. When the material is damaged, such as by mechanical stress causing changes in the relative positions of the molecular chains, the hydrogen bonds will break under certain temperature or pressure conditions. As the molecular chains move and adjust, the hydrogen bonds can reform. Because the formation and breaking of hydrogen bonds is a dynamic equilibrium process, the material can achieve self-repair in this way. For example, after minor scratch damage, by heating to a certain temperature (usually slightly higher than the glass transition temperature of the material), the molecular chains gain enough energy to move, the hydrogen bonds rearrange, and the damaged area is repaired.

[0066] The third layer belongs to the ionic bond system: in ionicly cross-linked polyvinyl alcohol, the ionic bonds are reversible under certain conditions. When the material is damaged, under thermal or mechanical stress, the ionic bonds dissociate, producing free ions and groups with opposite charges. The presence of these charged particles allows the molecular chains to move relative to each other, filling the damaged areas. When external conditions recover or after appropriate treatment, the ionic bonds reform, completing the self-repair process. For example, at higher temperatures, the ionic bonds in ionicly cross-linked polyvinyl alcohol dissociate, making the material more fluid and able to fill tiny cracks. After cooling, the ionic bonds reform, restoring the material's properties.

[0067] Quantum tunneling effect: In self-healing tunneling layers, electron transport relies on the quantum tunneling effect. Quantum tunneling is a quantum mechanical phenomenon where, when an electron faces an energy barrier, and the barrier width is sufficiently small, the electron has a certain probability of directly passing through the barrier without needing sufficient energy to cross its top. In the self-healing tunneling layer of a solar cell, the material's microstructure and energy level distribution create an environment suitable for quantum tunneling. For example, when metallic nanoparticles (such as silver or gold nanoparticles) are added to the tunneling layer, the nanoparticles and the surrounding polymer matrix form a nanoscale heterostructure. When electrons transport through these structures, the energy level difference between the nanoparticles and the polymer creates a potential barrier, and the nanoscale distance allows electrons to pass through the barrier via quantum tunneling, enabling transport from one layer to another.

[0068] The intelligent self-healing tunneling layer in this embodiment has a rapid response capability. Once microscopic damage occurs in the battery during operation, the self-healing mechanism can be initiated and complete the repair process in a very short time (usually within a few minutes or even less), thereby effectively preventing the further expansion and deterioration of the defect.

[0069] Example 2:

[0070] Embodiment 2 of the present invention provides an all-perovskite tandem solar cell based on a smart self-healing tunneling layer, as shown in the attached figure. Figure 2 The all-perovskite tandem solar cell includes, from bottom to top, a conductive substrate 1, a wide-bandgap perovskite solar cell 2, a smart self-healing tunneling layer 3 of Example 1, a narrow-bandgap perovskite solar cell 4, and an interface top electrode 5.

[0071] In one embodiment of the present invention, the wide-bandgap perovskite solar cell 2 is arranged in layers from bottom to top as follows: NiO x Or PTAA (polytriarylamine) thin film hole transport layer, crystalline Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 The active conductive layer and the PCBM (fullerene derivative) thin-film electron transport layer are stacked sequentially from bottom to top in the narrow bandgap perovskite solar cell 4: PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)) thin-film hole transport layer, crystalline FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 The I3 conductive active layer and the C60 and BCP electron transport layers. The conductive substrate 1 is made of ITO (indium tin oxide) or FTO (fluorine-doped tin oxide) conductive glass; the interface top electrode 5 is made of Ag with a thickness of 80~120 nm.

[0072] This embodiment of the intelligent self-healing tunneling layer perovskite tandem solar cell uses self-healing polymer molecules combined with highly conductive nanoparticles as the tunneling layer, significantly extending the lifespan and improving the stability of the perovskite tandem solar cell. When subjected to external stimuli (such as light, temperature changes, mechanical stress, etc.), the self-healing polymer molecules can automatically fill and repair microscopic defects and damage caused by various external factors through dynamic chemical bond rearrangement or molecular chain movement, optimizing interface performance and maintaining high photoelectric conversion efficiency. This reduces the frequent replacement and maintenance costs caused by battery performance degradation. Simultaneously, the highly conductive nanoparticles are uniformly dispersed in the polymer matrix, ensuring consistently high charge transport performance during the self-healing process.

[0073] Example 3:

[0074] Example 3 of this invention provides a method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer, as shown in the attached figure. Figure 3 The fabrication method of this all-perovskite tandem solar cell includes the following steps:

[0075] S1: Fabrication of wide-bandgap perovskite solar cells on a conductive substrate;

[0076] S2: A three-layer intelligent self-healing tunneling layer is formed by sequentially spin-coating a mixed solution of polyvinyl alcohol with ionic crosslinking dispersed gold nanoparticles, a mixed solution of polyamide with hydrogen bonds dispersed indium tin oxide nanoparticles, and a mixed solution of polyurethane with dispersed silver nanoparticles onto a wide-bandgap perovskite solar cell.

[0077] S3: Fabrication of narrow bandgap perovskite solar cells on intelligent self-healing tunneling layers;

[0078] S4: Fabrication of the interfacial top electrode on a narrow bandgap perovskite solar cell.

[0079] In one embodiment of the present invention, S2 includes:

[0080] S21. Preparation of the third layer of the intelligent self-healing tunneling layer:

[0081] In this embodiment, the degree of polymerization of the ionicly crosslinked polyvinyl alcohol is 1700~2500, and the average diameter of the gold nanoparticles is 8~12 nm.

[0082] Ionic cross-linked polyvinyl alcohol is dissolved in a solvent to prepare a solution with a concentration of 6-10 wt%. The solvent can be ethanol, DMF (N,N-dimethylformamide) or DMSO (dimethyl sulfoxide), etc. Based on the principle of like compatibility, ionic cross-linked polyvinyl alcohol has good solubility in ethanol, and is safe, environmentally friendly, stable, has a relatively low boiling point, and is not easily volatile. Therefore, ethanol is preferred.

[0083] Add gold nanoparticles at a concentration of 3-6 wt% and ultrasonically disperse for 25-40 min to obtain a mixed solution of polyvinyl alcohol with ionic crosslinking containing gold nanoparticles.

[0084] A mixed solution of polyvinyl alcohol with ionic crosslinking dispersed gold nanoparticles was spin-coated onto the surface of a wide-bandgap perovskite solar cell at a rotation speed of 1600-2000 rpm for 30-40 s and a solution flow rate of 0.06-0.1 mL / s.

[0085] Annealing was performed under nitrogen protection at a temperature of 90-110°C for 8-12 minutes to obtain a crystalline third layer of film.

[0086] S22. Preparation of the intermediate layer of the intelligent self-healing tunneling layer:

[0087] In this embodiment, the molecular weight of the hydrogen-bonded polyamide is 80,000~150,000 g / mol, and the average diameter of the indium tin oxide nanoparticles is 15~20 nm.

[0088] Hydrogen-bonded polyamides are dissolved in DMF (dimethylformamide) to prepare a solution with a concentration of 10-15 wt%.

[0089] Indium tin oxide nanoparticles were added at a concentration of 6-10 wt%, and the mixture was ultrasonically treated for 40-60 min to uniformly disperse the nanoparticles, thus obtaining a mixed solution of hydrogen-bonded polyamide and indium tin oxide nanoparticles.

[0090] A mixed solution of hydrogen-bonded polyamide and indium tin oxide nanoparticles was spin-coated onto the third layer at a rotation speed of 2000-2500 rpm for 40-50 s and a solution flow rate of 0.1-0.15 mL / s.

[0091] Annealing was performed under nitrogen protection at a temperature of 110-130°C for 15-20 minutes to obtain a crystalline intermediate layer for thin films.

[0092] S23. Preparation of the first layer of the intelligent self-healing tunneling layer:

[0093] In this embodiment, the molecular weight of the disulfide bond-based polyurethane is selected to be 50,000~100,000 g / mol, and the silver nanoparticles are prepared by chemical reduction method with an average diameter of 5~10 nm.

[0094] The disulfide bond-based polyurethane is dissolved in a solvent to prepare a solution with a concentration of 8-12 wt%. The solvent here is DMF (N,N-dimethylformamide) or NMP (N-methylpyrrolidone).

[0095] Silver nanoparticles were added, with the concentration of silver nanoparticles controlled at 4-8 wt%. The mixture was ultrasonically treated for 30-60 min to uniformly disperse the silver nanoparticles, thus obtaining a polyurethane mixed solution containing dispersed silver nanoparticles.

[0096] A mixed solution of polyurethane with dispersed silver nanoparticles was spin-coated onto the intermediate layer at a speed of 1800~2200 rpm for 30~40 s, with the solution flow rate controlled at 0.08~0.12 mL / s.

[0097] The material is placed in a tube furnace and annealed under a nitrogen atmosphere at a temperature of 80-100℃ for 10-15 minutes to obtain a first crystalline thin film.

[0098] S24. Overall processing:

[0099] The sample obtained in S23 was subjected to overall annealing or light treatment. The annealing temperature was 120~150℃ and the annealing time was 20~30 min. The light treatment was performed by irradiation with an ultraviolet lamp and a light intensity of 10~20 mW / cm². 2 The light exposure time is 1-2 hours.

[0100] During the preparation process, process parameters (such as solution concentration, coating speed, drying temperature, etc.) are strictly controlled to obtain a tunneling layer with uniform thickness, smooth surface and no pinholes.

[0101] In one embodiment of the present invention, S1 includes:

[0102] S11. Pre-treat the conductive substrate;

[0103] The pretreatment method used in this embodiment is as follows: the ITO or FTO conductive glass substrate is ultrasonically cleaned for 15 min each with a detergent, deionized water, acetone and anhydrous ethanol, and then dried with a high-purity nitrogen gun; the surface of the cleaned conductive glass substrate is then treated with UV-ozone for 30 min.

[0104] S12. Perform UV ozone treatment on the pretreated conductive substrate surface for 20-25 min, and spin-coat the UV ozone-treated conductive substrate surface with 10 mg / mL NiO.x Alternatively, annealing with a PTAA precursor solution at 120-150℃ for 20-30 min yields NiO with a thickness of 60-70 nm. x Or a PTAA thin-film hole transport layer;

[0105] S13, NiO after stabilization x Alternatively, a wide-bandgap perovskite Cs film can be spin-coated onto the surface of a PTAA thin-film hole transport layer. 0.2 FA 0.8 PbI 1.8 Br 1.2 The precursor solution was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. At the 30th s mark, 200 μL of the antisolvent CB (chlorobenzene) was added for extraction, followed by annealing at 100–110 °C for 10–15 min to obtain crystalline Cs with a thickness of 400–600 nm. 0.2 FA 0.8 PbI 1.8 Br 1.2 Thin-film conductive active layer;

[0106] S14, in the crystallization of Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 A precursor suspension of PCBM material was spin-coated onto a thin-film conductive active layer. The PCBM concentration was 20 mg / ml, the spin speed was 4000 rpm, the time was 40 s, and a PCBM thin-film electron transport layer with a thickness of 70~80 nm was grown.

[0107] In one embodiment of the present invention, S3 includes:

[0108] S31. Spin-coat the precursor solution of PEDOT:PSS onto the first layer and anneal it at 100~120℃ for 10~15 min to obtain a hole transport layer of PEDOT:PSS film with a thickness of 60~80 nm.

[0109] S32. Spin-coat a narrow-bandgap perovskite FA onto the surface of the stabilized PEDOT:PSS thin film hole transport layer. 0.7 MA 0.3 Pb 0.5 Sn 0.5 The precursor solution of I3 was annealed to obtain crystalline FA with a thickness of 800~1000 nm. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 thin-film conductive active layer;

[0110] S33, in FA0.7 MA 0.3 Pb 0.5 Sn 0.5 On the conductive active layer of the I3 thin film, a C60 layer with a thickness of 10~20 nm and a BCP layer with a thickness of 5~10 nm are sequentially prepared by thermal evaporation, which are combined to form a C60 and BCP electron transport layer.

[0111] In one embodiment of the present invention, the thickness of the Ag material of the top electrode of the interface is 80~120 nm.

[0112] The perovskite solar cell based on the intelligent self-healing tunneling layer prepared in Example 3 was tested.

[0113] See attached document Figure 4 The open-circuit voltage (VOC) of the device without the intelligent self-healing tunneling layer (traditional device) is 1.78V, the fill factor (FF) is 75.12%, and the short-circuit current density (JSC) is 17.97mA / cm². 2 The device has a power conversion efficiency (PCE) of 24.02%; the all-perovskite tandem solar cell based on a smart self-healing tunneling layer has an open-circuit voltage (VOC) of 1.82V, a fill factor (FF) of 76.21%, and a short-circuit current density (JSC) of 18.43mA / cm². 2 The device's power conversion efficiency (PCE) is 25.56%. This demonstrates that the use of a smart self-healing tunneling layer structure in this embodiment of an all-perovskite tandem solar cell improves the conversion efficiency, open-circuit voltage, and fill factor of the perovskite cell.

[0114] From the appendix Figure 5 As can be seen, the X-ray peak intensity of the all-perovskite solar cell based on the intelligent self-healing tunneling layer is higher, reflecting better crystallinity, higher phase purity and effective post-processing.

[0115] The advantages of the intelligent self-healing tunneling layer all-perovskite tandem solar cell of the present invention are as follows: 1) Significantly improved cell stability and lifespan: Through the self-healing mechanism, microscopic damage generated during use can be repaired in a timely manner, reducing performance degradation and thus significantly extending the lifespan of the perovskite tandem solar cell and reducing maintenance costs; 2) Enhanced photoelectric conversion efficiency: The optimized multilayer structure and efficient charge transport performance reduce charge recombination losses, allowing more light energy to be effectively converted into electrical energy, thereby improving the photoelectric conversion efficiency of the cell; 3) Stronger adaptability: It can work stably under a wider range of environmental conditions, such as harsh environments with large temperature variations and high humidity, expanding the application range of perovskite tandem solar cells; 4) Reduced costs: Long-term stable performance reduces the costs caused by frequent cell or module replacements. Moreover, the self-healing characteristic may reduce the dependence on high-quality, high-cost materials, thus providing an advantage in material costs; 5) Improved reliability: The self-healing function makes the cell performance more reliable, reducing the risk caused by performance instability and increasing the confidence of investors and users in perovskite tandem solar technology; 6) Improved process: The innovative preparation process is simpler, more efficient, and easier to mass-produce, which helps to promote the industrialization of perovskite solar cells.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All content that does not depart from the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart self-healing tunneling layer for an all-perovskite tandem solar cell, characterized in that, include: A first layer near the upper perovskite layer, a third layer near the lower perovskite layer, and an intermediate layer disposed between the first layer and the third layer; The first layer is composed of disulfide bond-based polyurethane with dispersed silver nanoparticles; The intermediate layer is composed of hydrogen-bonded polyamide with indium tin oxide nanoparticles dispersed therein; The third layer consists of polyvinyl alcohol with ionic crosslinking of dispersed gold nanoparticles.

2. A fully perovskite tandem solar cell based on a smart self-healing tunneling layer, characterized in that, It includes a conductive substrate, a wide-bandgap perovskite solar cell, the intelligent self-healing tunneling layer as described in claim 1, a narrow-bandgap perovskite solar cell, and an interface top electrode, which are stacked sequentially from bottom to top.

3. The all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 2, characterized in that, The wide-bandgap perovskite solar cells are stacked sequentially from bottom to top: NiO x Or PTAA thin film hole transport layer, crystalline Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 Conductive active layer and PCBM thin film electron transport layer.

4. The all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 2, characterized in that, The narrow bandgap perovskite solar cells are stacked sequentially from bottom to top as follows: PEDOT:PSS thin-film hole transport layer, crystalline FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 conductive active layer and C60 and BCP electron transport layer.

5. The all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 2, characterized in that, The conductive substrate is made of ITO or FTO conductive glass; the top electrode at the interface is made of Ag.

6. A method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer, characterized in that, Including the following steps: S1: Fabrication of wide-bandgap perovskite solar cells on a conductive substrate; S2: A three-layer intelligent self-healing tunneling layer is formed by sequentially spin-coating a mixed solution of polyvinyl alcohol with ionic crosslinking dispersed gold nanoparticles, a mixed solution of polyamide with hydrogen bonds dispersed indium tin oxide nanoparticles, and a mixed solution of polyurethane with dispersed silver nanoparticles onto the wide-bandgap perovskite solar cell. S3: Fabricate a narrow bandgap perovskite solar cell on the intelligent self-healing tunneling layer; S4: Fabricate an interface top electrode on the narrow bandgap perovskite solar cell.

7. The method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 6, characterized in that, S2 includes: S21. Prepare the third layer of the intelligent self-healing tunneling layer: Ionic cross-linked polyvinyl alcohol is dissolved in a solvent to prepare a solution with a concentration of 6-10 wt%. Add gold nanoparticles at a concentration of 3-6 wt% and ultrasonically disperse for 25-40 minutes to obtain a mixed solution of polyvinyl alcohol with ionic crosslinking containing gold nanoparticles. A mixed solution of polyvinyl alcohol with ionic crosslinking dispersed gold nanoparticles was spin-coated onto the surface of the wide-bandgap perovskite solar cell at a rotation speed of 1600~2000 rpm, a spin-coating time of 30~40 s, and a solution flow rate of 0.06~0.1 mL / s. Annealing was performed under nitrogen protection at a temperature of 90-110°C for 8-12 minutes to obtain a crystalline third layer of film. S22. Prepare the intermediate layer of the intelligent self-healing tunneling layer: Hydrogen-bonded polyamides are dissolved in a solvent to prepare a solution with a concentration of 10-15 wt%. Indium tin oxide nanoparticles were added at a concentration of 6-10 wt%, and the mixture was sonicated for 40-60 min to uniformly disperse the nanoparticles, thus obtaining a mixed solution of hydrogen-bonded polyamide and indium tin oxide nanoparticles. A mixed solution of hydrogen-bonded polyamide and indium tin oxide nanoparticles was spin-coated onto the third layer at a rotation speed of 2000-2500 rpm, a spin-coating time of 40-50 s, and a solution flow rate of 0.1-0.15 mL / s. Annealing was performed under nitrogen protection at a temperature of 110-130°C for 15-20 minutes to obtain a crystalline intermediate layer for thin films. S23. Prepare the first layer of the intelligent self-healing tunneling layer: Disulfide bond-based polyurethane is dissolved in a solvent to prepare a solution with a concentration of 8~12 wt%; Silver nanoparticles were added, with the concentration of silver nanoparticles controlled at 4-8 wt%. The mixture was ultrasonically treated for 30-60 min to uniformly disperse the silver nanoparticles, thus obtaining a polyurethane mixed solution containing dispersed silver nanoparticles. A mixed solution of polyurethane with dispersed silver nanoparticles was spin-coated onto the intermediate layer at a speed of 1800~2200 rpm for 30~40 s, with the solution flow rate controlled at 0.08~0.12 mL / s. The material is placed in a tube furnace and annealed under a nitrogen atmosphere at a temperature of 80-100℃ for 10-15 minutes to obtain a first crystalline thin film. S24. Overall processing: The sample obtained in S23 was subjected to overall annealing or light treatment. The annealing temperature was 120~150℃ and the annealing time was 20~30 min. The light treatment was performed by irradiation with an ultraviolet lamp and a light intensity of 10~20 mW / cm². 2 The light exposure time is 1-2 hours.

8. The method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 6, characterized in that, S1 includes: S11. Pre-treat the conductive substrate; S12. Perform UV ozone treatment on the pretreated conductive substrate surface for 20-25 min, and spin-coat the UV ozone-treated conductive substrate surface with 10 mg / mL NiO. x Alternatively, annealing with a PTAA precursor solution at 120-150℃ for 20-30 min yields NiO with a thickness of 60-70 nm. x Or a PTAA thin-film hole transport layer; S13, the NiO after stabilization x Alternatively, a wide-bandgap perovskite Cs film can be spin-coated onto the surface of a PTAA thin-film hole transport layer. 0.2 FA 0.8 PbI 1.8 Br 1.2 The precursor solution was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. At the 40th s mark, 200 μL of the antisolvent CB was added for extraction, followed by annealing at 100–110 °C for 10–15 min to obtain crystalline Cs with a thickness of 400–600 nm. 0.2 FA 0.8 PbI 1.8 Br 1.2 Thin-film conductive active layer; S14, in the crystallization of Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 A precursor suspension of PCBM material was spin-coated onto a thin-film conductive active layer. The PCBM concentration was 20 mg / ml, the spin speed was 4000 rpm, the time was 40 s, and a PCBM thin-film electron transport layer with a thickness of 70~80 nm was grown.

9. The method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 7, characterized in that, S3 includes: S31. Spin-coat a PEDOT:PSS precursor solution onto the first layer and anneal it at 100~120℃ for 10~15min to obtain a PEDOT:PSS thin film hole transport layer with a thickness of 60~80 nm. S32. Spin-coat a narrow-bandgap perovskite FA onto the surface of the stabilized PEDOT:PSS thin film hole transport layer. 0.7 MA 0.3 Pb 0.5 Sn 0.5 The precursor solution of I3 was annealed to obtain crystalline FA with a thickness of 800~1000 nm. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 thin-film conductive active layer; S33, in FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 On the conductive active layer of the I3 thin film, a C60 layer with a thickness of 10~20 nm and a BCP layer with a thickness of 5~10 nm are sequentially prepared by thermal evaporation, which are combined to form a C60 and BCP electron transport layer.

10. A method for fabricating an all-perovskite tandem solar cell based on a smart self-healing tunneling layer according to claim 6, characterized in that, The thickness of the Ag material in the top electrode of the interface is 80~120 nm.

Images