A 2D / 3D perovskite solar cell and its preparation method

Abstract

The present invention belongs to the field of solar cell technology and discloses a 2D / 3D perovskite solar cell and its preparation method. A glass slide is added to the surface of the 2D perovskite layer to allow full contact between the PEAI solution and the 3D perovskite surface. PEAI is used as a 2D perovskite barrier layer, and a 2D covering layer is grown in situ on top of the 3D perovskite film. The annealing method of the 2D layer and the concentration of PEAI are improved. A low-temperature carbon slurry is used to replace the hole transport layer (HTM) and the metal electrode to prepare a 2D / 3D perovskite solar cell. The present invention uses a low-temperature carbon slurry to replace the expensive hole transport layer (HTM) and metal electrode, avoiding the long-term placement of the metal electrode and the perovskite layer. It also greatly reduces the experimental cost. The perovskite cell prepared by the present invention has low cost and significantly improved thermal stability. After heating at 70°C for 10 hours, it can still maintain 90% of the initial efficiency and the photoelectric efficiency can reach 14.63%.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a 2D / 3D perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskites are among the most studied and promising optoelectronic materials due to their exceptional optoelectronic properties, tunable energy bands, high light absorption coefficients, and low exciton binding energies. Perovskite solar cells (PeSCs) have achieved remarkable success in photoelectric conversion over the past decade, with the highest certified photoelectric conversion efficiency (PCE) for perovskite solar cells reaching 25.7%, approaching the Shockley-Queisser limit. Perovskite cells have shown promising application prospects in next-generation photovoltaic devices. However, several challenges need to be addressed before commercial production, such as the formation of large surface defects that lead to severe non-radiative recombination, and insufficient material interactions between components that lead to thermal, moisture, and light-induced degradation.

[0003] Two-dimensional perovskites, a novel class of photovoltaic materials in which organic layers act as protective barriers against moisture or ion attack, have recently emerged and garnered increasing attention due to their remarkable stability. Inspired by this, surface passivation using two-dimensional perovskites deposited on top of three-dimensional perovskites has sparked a wave of research to simultaneously achieve higher efficiency and stability. This structure, by in situ growing a two-dimensional capping layer atop a 3D perovskite film, significantly improves the stability and photovoltaic performance of PSCs without compromising their high performance. Currently, PSCs have achieved remarkable performance with the help of two-dimensional perovskite surface passivation. For example, Yang et al. employed a newly designed cyclohexylethylammonium iodide (CEAI) as a surface passivator for 3D perovskites. By forming a 2D perovskite layer to reduce trap-assisted recombination, they achieved an increase in fill factor to 82.6%, resulting in a 23.57% improvement in PCE. The introduction of CEAI also improved surface hydrophobicity, enabling the passivated device to maintain a residual efficiency above 96% at 1 sun after 1500 hours. The record certified efficiency of PSCs (25.2%) obtained by Jin and colleagues is also based on a 2D perovskite passivation film. The basic light absorption layer is a 2D / 3D heterojunction induced by octylammonium iodide (OAI) and n-hexylammonium. In addition, Wang et al. successfully fabricated a thermodynamically stable all-inorganic (β-CsPbI3-based) PSC with an efficiency of >18% by using choline iodide (CHI) in crack filling interface engineering. In terms of carbon electrode-based perovskite cells, the German Wagner team introduced a two-dimensional perovskite passivation layer (OAI) as an electron blocking layer, significantly reducing interfacial recombination losses. This has enabled the use of two-dimensional perovskite as an electron blocking layer to achieve an HTM-free, printable, low-temperature carbon electrode perovskite solar cell with an efficiency of 18.5%, and significantly improved device stability.

[0004] In summary, 2D / 3D perovskite cells have better performance and greatly improved stability compared to traditional 3D perovskite cells, which will help the commercialization of perovskite solar cells.

[0005] The above analysis reveals the following problems and drawbacks of the existing technology: During the perovskite film formation process, dangling bonds at grain boundaries and crystal planes lead to a large number of grain boundary and interface defects. These harmful defects severely impair carrier transport and cause severe non-radiative recombination. Furthermore, due to insufficient interactions between their components, perovskite materials are subject to varying degrees of decomposition, which is accelerated when exposed to high humidity, high temperature, strong light, and oxygen-rich conditions. Currently, the in-situ growth of a 2D capping layer on top of a 3D perovskite film has significantly improved the stability of the PSC under standard conditions and the photovoltaic performance of the cell without compromising its high performance. However, the stability of perovskite cells in conditions such as high temperature, high humidity, and light exposure remains a concern. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a 2D / 3D perovskite solar cell and a preparation method thereof, and in particular relates to an improved 2D layer annealing method.

[0007] The present invention is achieved by providing a method for preparing a 2D / 3D perovskite solar cell, the method comprising:

[0008] A glass slide was placed on the surface of the 2D perovskite layer to ensure full contact between the PEAI solution and the 3D perovskite surface. PEAI was used as a 2D perovskite barrier layer, and a 2D covering layer was in situ grown on top of the 3D perovskite film. The annealing method of the 2D layer and the concentration of PEAI were improved. Low-temperature carbon slurry was used to replace the hole transport layer HTM and the metal electrode to prepare a 2D / 3D perovskite solar cell.

[0009] Furthermore, the preparation method of the 2D / 3D perovskite solar cell comprises the following steps:

[0010] Step 1: Preparation of electron transport layer, including the preparation of TiO2 dense layer, TiO2 nanoarray and SnO2 layer;

[0011] Step 2: Prepare the perovskite layer and the 2D layer separately;

[0012] Step three: fabricate the C electrode using a screen printing process.

[0013] Furthermore, the preparation of the TiO2 dense layer in step 1 includes:

[0014] The conductive glass FTO was ultrasonically treated with detergent powder, deionized water, acetone, and ethanol for 30 minutes each. After cleaning, the FTO was blown dry from the side with a clean nitrogen gun. After sticking yellow tape on the conductive surface of the glass to leave a reserved electrode, the substrate was placed in an ozone cleaner and cleaned for 30 minutes. 2.2 mL of titanium tetrachloride was added dropwise into 200 mL of an ice-water mixture and stirred to melt. The solution became clear and transparent. The prepared TiCl4 solution had a concentration of 0.1 M, and a cp-TiO2 precursor solution was obtained. The ozone-treated FTO was placed in a clean glass Petri dish and the prepared TiCl4 precursor solution was slowly poured in. The sealed Petri dish was placed in a water bath heated to 70°C, reacted for 2 hours, and then taken out and allowed to stand for 30 minutes. After cooling to room temperature, it was cleaned with deionized water and annealed on a 150°C hot plate for 2 hours. The cp-TiO2 sample was completed.

[0015] Furthermore, the TiO2 nanoarray preparation in step 1 includes:

[0016] Prepare 100 mL of a mixed solution of hydrochloric acid and deionized water with a volume ratio of 1:1, seal it tightly, and place it on a magnetic stirrer and stir it at room temperature for 30 minutes. After stirring, slowly add 1.5 mL of tetrabutyl titanate solution and stir thoroughly to obtain a precursor solution. Transfer the prepared cp-TiO2 sample to the inner liner of the reactor, place the conductive glass surface upward, pour in the stirred precursor solution, place it in the reactor, and heat it at 150°C in a drying oven for 105 minutes. After the reaction time is over, take out the sample, wash it with deionized water, place it in a muffle furnace and anneal it at 150°C for 2 hours. The TiO2 NA is completed.

[0017] Furthermore, the SnO2 layer preparation in step 1 includes:

[0018] Take 1mL of tin tetrachloride and put it into 200mL of deionized water, stir until it is completely mixed. The preparation method is the same as that of TiO2 dense layer.

[0019] Furthermore, the perovskite layer preparation in step 2 includes:

[0020] A certain amount of PbI2 powder was weighed and dissolved in a mixed solvent of DMF and DMSO, with V:V=9:1, and the concentration of PbI2 solution was prepared to be 1.5M. It was placed on a magnetic stirrer and heated and stirred at 70℃ for 30 minutes; 6.39mg, 9mg and 90mg of iodomethylamine, chloromethylamine and iodoformamidine powder were taken respectively, 1mL of isopropanol solution was added to the mixed drug powder, and the mixture was placed on a shaker and shaken continuously for 15 minutes; the first step of the two-step spin coating method was to spin-coat the PbI2 solution. A pipette was used to take 50μL of PbI2 solution and drop it on the UV-treated substrate surface; the spin coating speed was 1500rpm and the spin coating time was 30s, and it was placed on a 70℃ hot stage for annealing for 10s; the organic salt solution was spin-coated. 50μL of organic salt was spin-coated on the sample at a spin coating speed of 1500rpm and a spin coating time of 30s; after the spin coating was completed, it was immediately removed and placed on a 150℃ constant temperature hot stage for annealing for 30 minutes, and the PeSK film was prepared.

[0021] Furthermore, the 2D layer production in step 2 includes:

[0022] The prepared perovskite layer was post-treated by spin coating a PEAI solution with a concentration of 10 mg / mL. The PEAI spin coating speed was 5000 rpm, the acceleration was 9000 rpm, and the time was 30 s. After the spin coating was completed, a glass slide was placed on the upper surface to ensure full contact between the perovskite and the PEAI solution, and the layer was placed on a 100°C constant temperature hot plate for annealing for 10 minutes. After cooling to room temperature, the glass cover was removed.

[0023] Furthermore, the C electrode preparation in step 3 includes:

[0024] The low-temperature carbon paste was transferred to the 2D-3D layer using a screen printing process. After the transfer process was completed, it was immediately placed on a constant temperature hot stage for annealing for 10 min at 100 °C.

[0025] Furthermore, the preparation process of the 2D / 3D perovskite solar cell is carried out in air at a temperature of 25-28° C. and a humidity of 27-30%.

[0026] Another object of the present invention is to provide a 2D / 3D perovskite solar cell prepared by implementing the method for preparing a 2D / 3D perovskite solar cell.

[0027] In combination with the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solutions to be protected by the present invention from the following aspects:

[0028] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving these problems, this paper closely combines the technical solutions to be protected by the present invention and the results and data during the research and development process, and analyzes in detail and in depth how the technical solutions of the present invention solve the technical problems and some creative technical effects brought about by solving the problems. The specific description is as follows:

[0029] To address the problems existing in perovskite cells and the shortcomings of existing technologies, the present invention significantly improves the stability of PSCs and the photovoltaic performance of the cell by in-situ growing a 2D capping layer on top of a 3D perovskite film without affecting its high performance. Currently, the production process of 2D / 3D perovskites has gradually matured, and most research has only focused on the stability of devices under room temperature and dry conditions. For devices to be industrialized, they must withstand conditions such as high temperature and high humidity. However, the stability of 2D / 3D perovskites under conditions such as light, high temperature, and high humidity is still lacking. The present invention uses PEAI as a 2D perovskite barrier layer. By improving the annealing method of the 2D layer, a glass slide is added to the surface of the 2D perovskite layer during annealing to ensure full contact between the PEAI solution and the 3D perovskite surface. At the same time, the glass cover reduces the volatilization of the PEAI solution, forming a smooth 2D perovskite layer on the surface. Surface morphology testing revealed that the surface morphology of the 2D / 3D perovskite film was smooth and free of obvious defects, and the grains were tightly and evenly arranged. The light absorption capacity was also significantly improved. At the same time, it can be seen from XRD that there is no yellow phase in the 2D / 3D perovskite film, and the ratio of the perovskite peak to the residual lead iodide peak is significantly lower than that of the 3D perovskite, which proves that the quality of the 2D / 3D perovskite film of the present invention has been significantly improved. The stability of the 2D / 3D perovskite cell covered with a glass cover is higher than that of the 3D perovskite cell in harsh environments such as light, high temperature, and high humidity. After heating at 70°C for 10 hours, the efficiency still maintains 90% of the initial efficiency. The experiment was completely carried out in the air, and the experimental process is more convenient. At the same time, the present invention uses low-temperature carbon slurry to replace the expensive hole transport layer HTM and metal electrodes, which not only avoids the long-term mutual penetration of the metal electrode and the perovskite layer, but also greatly reduces the experimental cost.

[0030] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0031] The perovskite battery prepared by the present invention has low cost and significantly improved thermal stability. After being heated at 70° C. for 10 hours, it can still maintain 90% of the initial efficiency and the photoelectric efficiency can reach 14.63%.

[0032] Third, as auxiliary evidence for the inventiveness of the claims of the present invention, it is also reflected in the fact that the technical solution of the present invention solves a technical problem that people have long been eager to solve but have never been able to solve successfully:

[0033] While the manufacturing process for 2D / 3D perovskites has matured, the industrialization of perovskite solar cells requires them to withstand conditions such as sunlight, high temperature, and high humidity. Stability under these conditions presents a significant challenge for the industrialization of perovskite cells. However, a comprehensive solution to this problem currently remains unresolved. This paper proposes an improved annealing method for 2D / 3D perovskite cells, enhancing their stability under these conditions while maintaining simplicity and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 This is a flow chart of a method for preparing a 2D / 3D perovskite solar cell provided by an embodiment of the present invention;

[0036] Figure 2 is a SEM surface image of a perovskite film provided by an embodiment of the present invention;

[0037] Figure 3 is a structural diagram of a perovskite battery provided by an embodiment of the present invention;

[0038] Figure 4 is a UV-vis absorption spectrum of a 2D / 3D perovskite layer provided by an embodiment of the present invention;

[0039] Figure 5 is an XRD pattern of the perovskite layer provided in an embodiment of the present invention;

[0040] Figure 6 2D / 3D perovskite battery provided by an embodiment of the present invention;

[0041] Figure 7 This is a thermal stability diagram of a 2D / 3D perovskite cell provided by an embodiment of the present invention;

[0042] Figure 8 This is a stability diagram of a 2D / 3D perovskite battery provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] In response to the problems existing in the prior art, the present invention provides a 2D / 3D perovskite solar cell and a preparation method thereof. The present invention is described in detail below with reference to the accompanying drawings.

[0045] 1. Explanatory Examples In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an illustrative example that expands upon the technical solutions of the claims.

[0046] like Figure 1 As shown, the method for preparing a 2D / 3D perovskite solar cell provided by an embodiment of the present invention includes the following steps:

[0047] S101, electron transport layer fabrication, including TiO2 dense layer, TiO2 nanoarray and SnO2 layer fabrication;

[0048] S102, fabricating a perovskite layer and a 2D layer respectively;

[0049] S103, a C electrode is manufactured using a screen printing process.

[0050] As a preferred embodiment, the method for preparing a 2D / 3D perovskite solar cell provided in the embodiment of the present invention specifically includes the following steps:

[0051] (1) Preparation of electron transport layer

[0052] To create a dense TiO2 layer: Ultrasonicate conductive glass (FTO) with detergent, deionized water, acetone, and ethanol for 30 minutes each. After cleaning, blow dry the FTO from the side with a clean nitrogen gun. Tape the conductive surface of the glass with yellow tape to leave a reserved electrode. Place the substrate in an ozone cleaner and clean for 30 minutes. Add approximately 2.2 mL of titanium tetrachloride dropwise into a 200 mL ice-water mixture, stirring until the solution becomes clear and transparent. Prepare a 0.1 M TiCl4 solution, which serves as the cp-TiO2 precursor solution. Place the ozone-treated FTO in a clean glass Petri dish and slowly pour the prepared TiCl4 precursor solution into it. The sealed Petri dish is placed in a water bath heated to 70°C. After reacting for 2 hours, remove the dish and let it sit for 30 minutes. After cooling to room temperature, rinse with deionized water and anneal on a 150°C hotplate for 2 hours. The cp-TiO2 is complete.

[0053] Preparation of TiO2 nanoarrays: First, prepare 100mL of a 1:1 volume ratio (V:V) of hydrochloric acid and deionized water. After sealing tightly, place the mixture on a magnetic stirrer and stir at room temperature for 30 minutes. After stirring, slowly add 1.5mL of tetrabutyl titanate solution and stir thoroughly. Then, transfer the cp-TiO2 sample prepared above to the inner container of the reactor. Place the conductive glass surface upward, pour in the stirred precursor solution, place it in the reactor, and heat it in a drying oven at 150°C for 105 minutes. After the reaction time is over, remove the sample, rinse it with deionized water, and anneal it in a muffle furnace at 150°C for 2 hours. The TiO2 NA is then produced.

[0054] Preparation of SnO2 layer: Take 1mL of tin tetrachloride and add it to 200mL of deionized water. Stir until completely mixed. Preparation method is the same as that of TiO2 dense layer.

[0055] (2) Perovskite layer preparation

[0056] Perovskite layer fabrication: Weigh a certain amount of PbI2 powder and dissolve it in a mixture of DMF and DMSO (V:V = 9:1) to prepare a 1.5M PbI2 solution. Heat and stir at 70°C on a magnetic stirrer for 30 minutes. Add 6.39mg, 9mg, and 90mg of methylamine iodide (MAI), methylamine chloride (MACl), and formamidine iodide (FAI) powders to the mixture with 1mL of isopropyl alcohol (IPA) solution. The mixture is then shaken on a shaker for 15 minutes. A two-step spin coating method involves spin-coating the PbI2 solution. Using a pipette, 50μL of the PbI2 solution is dropped onto the UV-treated substrate surface. Spin coating is performed at 1500rpm for 30 seconds, followed by annealing on a 70°C hotplate for 10 seconds. Spin-coat the organic salt solution, take 50 μL of organic salt and spin-coat it on the sample. The spin-coating parameters are set to be consistent with the process parameters of spin-coating PbI2 solution. After the spin-coating is completed, immediately remove it and place it on a 150°C constant temperature hot plate for annealing for 30 minutes. At this point, the PeSK film preparation is completed.

[0057] 2D layer fabrication: Post-treatment is performed by spin-coating a PEAI solution on the prepared perovskite layer. The PEAI solution concentration is 10 mg / mL. The PEAI coating speed is 5000 rpm, the acceleration is 9000 rpm, and the coating time is 30 seconds. After spin coating, a glass slide is placed on the top surface to ensure full contact between the perovskite and the PEAI solution. The layer is then annealed on a 100°C hotplate for 10 minutes. After cooling to room temperature, the cover glass is removed.

[0058] (3) Electrode preparation

[0059] C electrode fabrication: The low-temperature carbon paste was transferred to the 2D-3D layer using a screen printing process. Immediately after the transfer process, the film was annealed on a 100°C hotplate for 10 minutes.

[0060] The above processes are all carried out in air with a temperature of 25-28°C and a humidity of 27-30%.

[0061] 2. Application Examples: In order to demonstrate the creativity and technical value of the technical solution of the present invention, this section provides application examples of the claimed technical solution on specific products or related technologies.

[0062] An embodiment of the present invention provides a method for preparing an electron transport layer of a 2D / 3D perovskite solar cell, which includes a 3D perovskite layer and a 2D barrier layer. The method comprises the following steps:

[0063] (1) Preparation of 3D perovskite layer on the prepared electron transport layer

[0064] Weigh a certain amount of PbI2 powder and dissolve it in a mixture of DMF and DMSO (V:V = 9:1) to prepare a 1.5M PbI2 solution. Heat and stir at 70°C on a magnetic stirrer for 30 minutes. Add 6.39mg, 9mg, and 90mg of methylamine iodide (MAI), methylamine chloride (MACl), and formamidine iodide (FAI) powders to the mixture with 1mL of isopropyl alcohol (IPA) solution. The mixture is then shaken on a shaker for 15 minutes. The first step in the two-step spin coating method is to spin-coat the PbI2 solution. Using a pipette, 50μL of the PbI2 solution is dropped onto the UV-treated substrate surface. Spin at 1500rpm for 30 seconds, followed by annealing on a 70°C hotplate for 10 seconds. Spin-coat the organic salt solution, take 50 μL of organic salt and spin-coat it on the sample. The spin-coating parameters are set to be consistent with the process parameters of spin-coating PbI2 solution. After the spin-coating is completed, immediately remove it and place it on a 150°C constant temperature hot plate for annealing for 30 minutes. At this point, the 3D perovskite film is prepared.

[0065] (2) Preparation of 2D barrier layer on 3D perovskite layer

[0066] Post-treatment was performed by spin-coating a PEAI solution on the prepared perovskite layer. The PEAI solution concentration was 10 mg / mL. The PEAI coating speed was 5000 rpm, the acceleration was 9000 rpm, and the coating time was 30 seconds. After spin coating, a glass slide was placed on the top surface to ensure full contact between the perovskite and the PEAI solution. The film was then annealed on a 100°C hotplate for 10 minutes. After cooling to room temperature, the cover glass was removed.

[0067] The lead iodide solution concentration used in step (1) is 1.5M

[0068] The mass ratio of the perovskite chemicals used in step (1) is MAI:MACl:FAI=6.39:9:90.

[0069] The PEAI concentration used in step (2) was 10 mg / mL.

[0070] An embodiment of the present invention provides a 2D / 3D perovskite solar cell, which comprises, from bottom to top, an FTO transparent conductive glass substrate, an electron transport layer, a perovskite layer, a 2D layer, and a carbon electrode. The perovskite layer is a FAMA perovskite material, and is the perovskite solar cell perovskite layer according to any one of claims 1 to 2. The 2D barrier layer is the 2D barrier layer of the 2D / 3D perovskite solar cell according to claim 3.

[0071] The thickness of the electron transport layer is 300 nm.

[0072] The thickness of the perovskite layer is 600 nm.

[0073] The thickness of the 2D layer is 30 nm.

[0074] The thickness of the carbon electrode layer is 5 μm.

[0075] 3. Evidence of the effects of the embodiments: The embodiments of the present invention have achieved some positive effects during the development or use process, and indeed have great advantages over the existing technology. The following content describes them with reference to the data, charts, etc. of the experimental process.

[0076] Example 1

[0077] The present invention provides a 2D / 3D perovskite solar cell. The solar cell comprises, from bottom to top, FTO transparent conductive glass, a TiO2 substrate, an electron transport layer, an absorption layer, a 2D layer, and a carbon electrode. The absorption layer is made of a perovskite material, and the 2D layer is made of PEAI. The manufacturing method includes the following steps:

[0078] 1. Clean the substrate

[0079] Conductive glass (FTO) was ultrasonically cleaned with detergent, deionized water, acetone, and ethanol for 30 minutes each. After cleaning, the FTO was blown dry from the side using a clean nitrogen gun. Yellow tape was applied to the conductive surface of the glass to leave a reserved electrode. The substrate was then placed in an ozone cleaner for 30 minutes.

[0080] 2. Make the electron transport layer

[0081] (1) TiO2 dense layer

[0082] Approximately 2.2 mL of titanium tetrachloride was dripped dropwise into a 200 mL ice-water mixture, stirred to melt, and the solution was clear and transparent. The prepared TiCl₄ solution had a concentration of 0.1 M and served as the precursor solution for cp-TiO₂. Next, the ozone-treated FTO was placed in a clean glass Petri dish and the prepared TiCl₄ precursor solution was slowly poured in. The sealed Petri dish was placed in a water bath heated to 70°C. After reacting for 2 hours, the dish was removed and allowed to stand for 30 minutes. After cooling to room temperature, it was rinsed with deionized water and annealed on a 150°C hot plate for 2 hours. The cp-TiO₂ was then produced.

[0083] (2) Fabrication of TiO2 nanoarrays

[0084] First, prepare 100 mL of a 1:1 volume ratio (V:V) of hydrochloric acid and deionized water. Stir at room temperature for 30 minutes, then dropwise add 1.5 mL of tetra-n-butyl titanate solution and stir thoroughly. Then, transfer the prepared cp-TiO2 sample to the inner liner of a reactor, pour in the stirred precursor solution, place it in the reactor, and heat it in a drying oven at 150°C for 105 minutes. After the reaction time is complete, remove the sample, rinse it with deionized water, and anneal it in a muffle furnace at 150°C for 2 hours. The TiO2 NA is then fabricated.

[0085] (3) SnO2 layer preparation

[0086] Take 1mL of tin tetrachloride and put it into 200mL of deionized water, and stir until it is completely mixed. The preparation method is the same as that of TiO2 dense layer.

[0087] 3. Perovskite layer production

[0088] Weigh a certain amount of PbI2 powder and dissolve it in a mixture of DMF and DMSO (V:V = 9:1) to prepare a 1.5M PbI2 solution. Heat and stir at 70°C on a magnetic stirrer for 30 minutes. Add 6.39mg, 9mg, and 90mg of methylamine iodide (MAI), methylamine chloride (MACl), and formamidine iodide (FAI) powders to the mixture with 1mL of isopropyl alcohol (IPA) solution. Shake the mixture on a shaker for 15 minutes. Spin coat the PbI2 solution by pipetting 50μL of the solution onto the UV-treated substrate. Spin at 1500rpm for 30 seconds. Anneal on a 70°C hotplate for 10 seconds. Spin-coat the organic salt solution, take 50 μL of organic salt and spin-coat it on the sample. The spin-coating parameters are set to be consistent with the process parameters of spin-coating PbI2 solution. After the spin-coating is completed, immediately remove it and place it on a 150°C constant temperature hot plate for annealing for 30 minutes. At this point, the PeSK film preparation is completed.

[0089] 4. 2D layer production

[0090] Post-treatment was performed by spin-coating a PEAI solution on the prepared perovskite layer. The PEAI solution concentration was 10 mg / mL. The PEAI coating speed was 5000 rpm, the acceleration was 9000 rpm, and the coating time was 30 seconds. After spin coating, a glass slide was placed on the top surface to ensure full contact between the perovskite and the PEAI solution. The film was then annealed on a 100°C hotplate for 10 minutes. After cooling to room temperature, the cover glass was removed.

[0091] 5. C electrode production

[0092] The low-temperature carbon paste was transferred to the 2D-3D layer using a screen printing process. Immediately after the transfer process, it was placed on a 100°C hot plate for annealing for 10 minutes.

[0093] Complete the assembly of the 2D / 3D perovskite solar cell.

[0094] The 2D / 3D perovskite films prepared in step 5 were analyzed by transmission spectroscopy, X-ray diffraction, and field-emission electron scanning microscopy. X-ray diffraction (XRD) analysis was performed using a D8 Advance instrument at a scanning angle of 0.001° / step. Electron scanning microscopy was performed at 20 kV.

[0095] The photoelectric performance of the 2D / 3D perovskite solar cells assembled above was also tested. The current density-photovoltage (J–V) characteristics of the devices were measured using a computer-controlled Keithley 2400 source meter. The tests were conducted in an environment simulating sunlight at AM1.5G with a power of 100 mW cm -2 A xenon lamp-based solar simulator (from Newport Co., Ltd.) was used to measure the external quantum efficiency (EQE) of the cell using a Stanford Research Systems DSP SR830 lock-in amplifier with a WDG3 monochromator and a 500W xenon lamp. The intensity of each wavelength was calibrated with a standard single-crystal silicon photovoltaic cell. These test results are listed in the accompanying figures.

[0096] in, Figure 2 The SEM surface image of the perovskite film provided by the embodiment of the present invention is shown in FIG. Figure 2 It can be clearly seen that the 2D / 3D perovskite film has good crystallinity, a smooth surface without obvious defects, and uniform 2D layer coverage, which is beneficial to the stability of the battery. The surface morphology of the 3D perovskite shows that the grain size varies, the crystallization is uneven, and the surface has defects and is uneven.

[0097] Figure 3 It is a structural diagram of a perovskite battery provided by an embodiment of the present invention.

[0098] Figure 4This is the UV-vis absorption spectrum of the 2D / 3D perovskite layer. Due to the good crystallinity and smooth surface of the perovskite film, the 2D / 3D perovskite film can absorb more visible light than the 3D perovskite film.

[0099] Figure 5 This is the XRD pattern of the perovskite layer provided by an embodiment of the present invention. The XRD peaks of the 2D perovskite layer can be seen in the 2D / 3D perovskite layer pattern, confirming the presence of the 2D perovskite. The XRD pattern contains few impurity peaks and no yellow phase perovskite peaks, demonstrating the good crystallinity of the perovskite film.

[0100] Figure 6 This is the JV curve of the 2D / 3D perovskite cell provided by the embodiment of the present invention. The open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency are: 1.038V, 24.54mA / cm 2 , 57.43% and 14.63%. JV curve of 3D perovskite cell. The open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency are: 1.02V, 24.97mA / cm 2 , 48.68% and 12.45%.

[0101] Figure 7 This is a graph showing the thermal stability of 2D / 3D perovskite cells provided by an embodiment of the present invention. It shows that after 10 hours of continuous heating at 70°C and an ambient humidity between 33% and 35%, the efficiency remains at 90% of the initial efficiency. However, the 3D perovskite film's efficiency drops below 80% of its initial efficiency after just 6 hours.

[0102] Figure 8 This is a stability graph of 2D / 3D perovskite cells provided by an embodiment of the present invention. It shows that after 30 days of storage under dry, room-temperature conditions, the efficiency of the 2D / 3D perovskite cell still remained at 90% of its initial efficiency, while the efficiency of the 3D perovskite cell had already dropped to 83% of its initial efficiency by day 7, and only 45% of its initial efficiency by day 30. This indicates that the stability of 2D / 3D perovskite cells has been significantly improved.

[0103] Example 2

[0104] 1. Clean the substrate

[0105] Conductive glass (FTO) was ultrasonically cleaned with detergent, deionized water, acetone, and ethanol for 30 minutes each. After cleaning, the FTO was blown dry from the side using a clean nitrogen gun. Yellow tape was applied to the conductive surface of the glass to leave a reserved electrode. The substrate was then placed in an ozone cleaner for 30 minutes.

[0106] 2. Make the electron transport layer

[0107] (1) TiO2 dense layer

[0108] Approximately 2.2 mL of titanium tetrachloride was dripped dropwise into a 200 mL ice-water mixture, stirred to melt, and the solution was clear and transparent. The prepared TiCl₄ solution had a concentration of 0.1 M and served as the precursor solution for cp-TiO₂. Next, the ozone-treated FTO was placed in a clean glass Petri dish and the prepared TiCl₄ precursor solution was slowly poured in. The sealed Petri dish was placed in a water bath heated to 70°C. After reacting for 2 hours, the dish was removed and allowed to stand for 30 minutes. After cooling to room temperature, it was rinsed with deionized water and annealed on a 150°C hot plate for 2 hours. The cp-TiO₂ was then produced.

[0109] (2) Fabrication of TiO2 nanoarrays

[0110] First, prepare 100 mL of a 1:1 volume ratio (V:V) of hydrochloric acid and deionized water. Stir at room temperature for 30 minutes, then dropwise add 1.5 mL of tetra-n-butyl titanate solution and stir thoroughly. Then, transfer the prepared cp-TiO2 sample to the inner liner of a reactor, pour in the stirred precursor solution, place it in the reactor, and heat it in a drying oven at 150°C for 105 minutes. After the reaction time is complete, remove the sample, rinse it with deionized water, and anneal it in a muffle furnace at 150°C for 2 hours. The TiO2 NA is then fabricated.

[0111] (3) SnO2 layer preparation

[0112] Take 1mL of tin tetrachloride and put it into 200mL of deionized water, and stir until it is completely mixed. The preparation method is the same as that of TiO2 dense layer.

[0113] 3. Perovskite layer production

[0114] Weigh a certain amount of PbI2 powder and dissolve it in a mixture of DMF and DMSO (V:V = 9:1) to prepare a 1.5M PbI2 solution. Heat and stir at 70°C on a magnetic stirrer for 30 minutes. Add 6.39mg, 9mg, and 90mg of methylamine iodide (MAI), methylamine chloride (MACl), and formamidine iodide (FAI) powders to the mixture with 1mL of isopropyl alcohol (IPA) solution. Shake the mixture on a shaker for 15 minutes. Spin coat the PbI2 solution by pipetting 50μL of the solution onto the UV-treated substrate. Spin at 1500rpm for 30 seconds. Anneal on a 70°C hotplate for 10 seconds. Spin-coat the organic salt solution, take 50 μL of organic salt and spin-coat it on the sample. The spin-coating parameters are set to be consistent with the process parameters of spin-coating PbI2 solution. After the spin-coating is completed, immediately remove it and place it on a 150°C constant temperature hot plate for annealing for 30 minutes. At this point, the PeSK film preparation is completed.

[0115] 4. 2D layer production

[0116] Post-treatment was performed by spin-coating a PEAI solution onto the prepared perovskite layer. The PEAI solution concentration was 5 mg / mL. The PEAI coating speed was 5000 rpm, the acceleration was 9000 rpm, and the coating time was 30 seconds. After spin coating, a glass slide was placed on the top surface to ensure full contact between the perovskite and the PEAI solution. The film was then annealed on a 100°C hotplate for 10 minutes. After cooling to room temperature, the cover glass was removed.

[0117] 5. C electrode production

[0118] The low-temperature carbon paste was transferred to the 2D-3D layer using a screen printing process. Immediately after the transfer process, it was placed on a 100°C hot plate for annealing for 10 minutes.

[0119] JV curve of the 2D / 3D perovskite cell of the present invention. The open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency are: 1.029V, 24.69mA / cm 2 , 51.93% and 13.46%. The absorption value of UV-vis absorption spectrum is slightly lower than that of Example 1, and there is no obvious difference in SEM and XRD results.

[0120] Example 3

[0121] 1. Clean the substrate

[0122] Conductive glass (FTO) was ultrasonically cleaned with detergent, deionized water, acetone, and ethanol for 30 minutes each. After cleaning, the FTO was blown dry from the side using a clean nitrogen gun. Yellow tape was applied to the conductive surface of the glass to leave a reserved electrode. The substrate was then placed in an ozone cleaner for 30 minutes.

[0123] 2. Make the electron transport layer

[0124] (1) TiO2 dense layer

[0125] Approximately 2.2 mL of titanium tetrachloride was dripped dropwise into a 200 mL ice-water mixture, stirred to melt, and the solution was clear and transparent. The prepared TiCl₄ solution had a concentration of 0.1 M and served as the precursor solution for cp-TiO₂. Next, the ozone-treated FTO was placed in a clean glass Petri dish and the prepared TiCl₄ precursor solution was slowly poured in. The sealed Petri dish was placed in a water bath heated to 70°C. After reacting for 2 hours, the dish was removed and allowed to stand for 30 minutes. After cooling to room temperature, it was rinsed with deionized water and annealed on a 150°C hot plate for 2 hours. The cp-TiO₂ was then produced.

[0126] (2) Fabrication of TiO2 nanoarrays

[0127] First, prepare 100 mL of a 1:1 volume ratio (V:V) of hydrochloric acid and deionized water. Stir at room temperature for 30 minutes, then dropwise add 1.5 mL of tetra-n-butyl titanate solution and stir thoroughly. Then, transfer the prepared cp-TiO2 sample to the inner liner of a reactor, pour in the stirred precursor solution, place it in the reactor, and heat it in a drying oven at 150°C for 105 minutes. After the reaction time is complete, remove the sample, rinse it with deionized water, and anneal it in a muffle furnace at 150°C for 2 hours. The TiO2 NA is then fabricated.

[0128] (3) SnO2 layer preparation

[0129] Take 1mL of tin tetrachloride and put it into 200mL of deionized water, and stir until it is completely mixed. The preparation method is the same as that of TiO2 dense layer.

[0130] 3. Perovskite layer production

[0131] Weigh a certain amount of PbI2 powder and dissolve it in a mixture of DMF and DMSO (V:V = 9:1) to prepare a 1.5M PbI2 solution. Heat and stir at 70°C on a magnetic stirrer for 30 minutes. Add 6.39mg, 9mg, and 90mg of methylamine iodide (MAI), methylamine chloride (MACl), and formamidine iodide (FAI) powders to the mixture with 1mL of isopropyl alcohol (IPA) solution. Shake the mixture on a shaker for 15 minutes. Spin coat the PbI2 solution by pipetting 50μL of the solution onto the UV-treated substrate. Spin at 1500rpm for 30 seconds. Anneal on a 70°C hotplate for 10 seconds. Spin-coat the organic salt solution, take 50 μL of organic salt and spin-coat it on the sample. The spin-coating parameters are set to be consistent with the process parameters of spin-coating PbI2 solution. After the spin-coating is completed, immediately remove it and place it on a 150°C constant temperature hot plate for annealing for 30 minutes. At this point, the PeSK film preparation is completed.

[0132] 4. 2D layer production

[0133] Post-treatment was performed by spin-coating a PEAI solution on the prepared perovskite layer. The PEAI solution concentration was 10 mg / mL. The PEAI coating speed was 4000 rpm, the acceleration was 9000 rpm, and the coating time was 30 seconds. After spin coating, a glass slide was placed on the top surface to ensure full contact between the perovskite and the PEAI solution. The film was then annealed on a 100°C hotplate for 10 minutes. After cooling to room temperature, the cover glass was removed.

[0134] 5. C electrode production

[0135] The low-temperature carbon paste was transferred to the 2D-3D layer using a screen printing process. Immediately after the transfer process, it was placed on a 100°C hot plate for annealing for 10 minutes.

[0136] JV curve of the 2D / 3D perovskite cell of the present invention. The open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency are: 1.024V, 24.89mA / cm 2 , 55.93% and 14.26%. The absorption spectrum is similar to that of Example 1.

[0137] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a 2D / 3D perovskite solar cell, characterized in that: The preparation method of the 2D / 3D perovskite solar cell comprises: A glass slide was placed on the surface of the 2D perovskite layer to ensure full contact between the PEAI solution and the 3D perovskite surface. PEAI was used as a barrier layer for the 2D perovskite, and a 2D capping layer was grown in situ on top of the 3D perovskite film. The annealing method of the 2D layer and the concentration of PEAI were improved. A low-temperature carbon slurry was used to replace the hole transport layer (HTM) and the metal electrode to prepare a 2D / 3D perovskite solar cell. The method for preparing the 2D / 3D perovskite solar cell comprises the following steps: Step 1: Preparation of electron transport layer, including the preparation of TiO2 dense layer, TiO2 nanoarray and SnO2 layer; Step 2: Prepare the perovskite layer and the 2D layer separately; Step 3: Using screen printing technology to make C electrode; The preparation of the TiO2 dense layer in step 1 includes: The conductive glass FTO was treated with washing powder, deionized water, acetone, and ethanol, and ultrasonicated for 30 minutes respectively. After cleaning, the FTO was blown dry from the side with a clean nitrogen gun; after sticking yellow tape on the conductive surface of the glass to leave a reserved electrode, the substrate was placed under an ozone cleaner and cleaned for 30 minutes; 2.2mL of titanium tetrachloride was added dropwise into 200mL of ice-water mixture, stirred to melt, and the solution became clear and transparent. The prepared TiCl4 solution concentration was 0.1M, and a cp-TiO2 precursor solution was obtained; the ozone-treated FTO was placed in a clean glass culture dish, and the prepared TiCl4 precursor solution was slowly poured in. The sealed culture dish was placed in a water bath that had been heated to 70°C, reacted for 2 hours, and then taken out and allowed to stand for 30 minutes; after cooling to room temperature, it was cleaned with deionized water and annealed on a 150°C hot plate for 2 hours, and the cp-TiO2 sample was completed; The 2D layer production in step 2 includes: The prepared perovskite layer was post-treated by spin coating a PEAI solution with a concentration of 10 mg / mL. The PEAI spin coating speed was 5000 rpm, the acceleration was 9000 rpm, and the time was 30 s. After the spin coating was completed, a glass slide was placed on the upper surface to ensure full contact between the perovskite and the PEAI solution, and the layer was placed on a 100°C constant temperature hot plate for annealing for 10 minutes. After cooling to room temperature, the glass cover was removed.

2. The method for preparing a 2D / 3D perovskite solar cell according to claim 1, wherein: The TiO2 nanoarray production in step 1 includes: Prepare 100 mL of a mixed solution of hydrochloric acid and deionized water with a volume ratio of 1:1, seal it tightly, and place it on a magnetic stirrer and stir it at room temperature for 30 minutes. After stirring, slowly add 1.5 mL of tetrabutyl titanate solution and stir thoroughly to obtain a precursor solution; transfer the prepared cp-TiO2 sample to the inner liner of the reactor, place the conductive glass surface upward, pour in the stirred precursor solution, place it in the reactor, and heat it at 150°C in a drying oven for 105 minutes; after the reaction time is over, take out the sample, wash it with deionized water, place it in a muffle furnace and anneal it at 150°C for 2 hours, and the TiO2NA is completed.

3. The method for preparing a 2D / 3D perovskite solar cell according to claim 1, wherein: The perovskite layer preparation in step 2 includes: A certain amount of PbI2 powder was weighed and dissolved in a mixed solvent of DMF and DMSO with a V:V ratio of 9:1 to prepare a PbI2 solution with a concentration of 1.5M. The solution was placed on a magnetic stirrer and heated at 70°C for 30 minutes. 6.39 mg, 9 mg, and 90 mg of iodomethylamine, chloromethylamine, and iodoformamidine powders were taken respectively, and 1 mL of isopropanol solution was added to the mixed drug powders. The mixture was placed on a shaker and shaken continuously for 15 minutes. The first step of the two-step spin coating method was to spin-coat the PbI2 solution. A pipette was used to take 50 µL of the PbI2 solution and drop it on the UV-treated substrate surface. The spin coating speed was 1500 rpm and the spin coating time was 30 seconds. The sample was then placed on a 70°C hot plate for annealing for 10 seconds. The organic salt solution was spin-coated. 50 µL of the organic salt was spin-coated on the sample at a spin coating speed of 1500 rpm for 30 seconds. After spin coating, the sample was immediately removed and placed on a 150°C constant temperature hot plate for annealing for 30 minutes. The PVSK film was prepared.

4. The method for preparing a 2D / 3D perovskite solar cell according to claim 1, wherein: The C electrode preparation in step 3 includes: The low-temperature carbon paste was transferred to the 2D / 3D layer using a screen printing process. After the transfer process was completed, it was immediately placed on a constant temperature hot stage for annealing for 10 min at 100 °C.

5. The method for preparing a 2D / 3D perovskite solar cell according to claim 1, wherein: The preparation process of the 2D / 3D perovskite solar cell is carried out in air at a temperature of 25-28° C. and a humidity of 27-30%.

6. A 2D / 3D perovskite solar cell prepared by the method for preparing a 2D / 3D perovskite solar cell according to any one of claims 1 to 5.

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