Perovskite solar cell preparation method and perovskite solar cell

Abstract

This invention discloses a method for fabricating perovskite solar cells and the perovskite solar cell itself. The fabrication method includes the following steps: providing a substrate with a TCO conductive layer; forming a stacked structure containing a SnOx thin film on the substrate; and performing scanning sintering treatment on the SnOx thin film using an infrared laser to form an electron transport layer. The perovskite solar cell includes: a substrate with a TCO conductive layer; a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer stacked on the substrate; wherein the electron transport layer is fabricated using this method. This invention uses laser to locally and rapidly heat the SnOx thin film, which can efficiently improve the crystallinity of the film and repair its defects while avoiding damage to the underlying material.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a method for preparing perovskite solar cells and perovskite solar cells. Background Technology

[0002] Perovskite solar cells, as a high-efficiency, low-cost next-generation photovoltaic technology, rely heavily on the optimization of their functional layers for performance. Among these, the electron transport layer is crucial for extracting electrons, blocking holes, and stabilizing the interface. Currently, C60 (fullerene) thin films are commonly used as electron transport layers in perovskite solar cells, but this approach has significant limitations: weak bonding with the perovskite interface leads to severe nonradiative recombination and open-circuit voltage (Voc) loss; the films also have poor mechanical strength, making them prone to cracking and peeling, with the C60 film fracture energy being only about 0.3 J·m. - ², under thermal cycling and mechanical stress, it is prone to cracking and delamination, which affects the reliability of the device; C60 has a weak blocking effect on holes, which easily leads to hole leakage and reduces the overall efficiency of the device; moreover, the loose packing of C60 molecules results in insufficient water and oxygen barrier, which accelerates the degradation of perovskite and significantly shortens the device life.

[0003] Therefore, tin oxide has become an ideal alternative material due to its excellent electrical properties and stability. In existing technologies, the preparation methods for SnOx electron transport layers mainly include solution methods (sol-gel method, nanoparticle dispersion spin-coating method) and atomic layer deposition (ALD). Solution methods cannot meet the needs of large-scale mass production, making ALD deposition of SnOx films the current optimal choice. However, SnOx films prepared by ALD have defects such as oxygen vacancies and low crystallinity. Traditional optimization methods such as high-temperature annealing and doping modification can easily damage the heat-sensitive perovskite layer and flexible substrate, severely limiting the performance of perovskite solar cells.

[0004] Therefore, designing methods for preparing high-performance SnOx electron transport layers is of great significance for promoting the industrialization of perovskite solar cells. Summary of the Invention

[0005] To address the shortcomings of low crystallinity and poor performance of SnOx thin films in existing technologies, this invention proposes a method for preparing perovskite solar cells and a perovskite solar cell. By using laser to rapidly heat the SnOx thin film locally, the crystallinity of the film can be efficiently improved and its defects repaired while avoiding damage to the underlying material.

[0006] The technical solution adopted in this invention is to design a method for fabricating perovskite solar cells, including the following steps:

[0007] Provide a substrate with a TCO conductive layer;

[0008] A stacked structure containing SnOx thin films is formed on a substrate;

[0009] Infrared lasers are used to scan and sinter SnOx thin films to form an electron transport layer.

[0010] This design utilizes the rapid, localized heating characteristics of infrared lasers to sinter SnOx thin films, effectively improving the crystal quality and reducing defects of the films without damaging the heat-sensitive underlying material, thereby significantly optimizing their electron transport performance.

[0011] For inverted (pin) perovskite solar cells, the hole transport layer is located between the perovskite light-absorbing layer and the TCO conductive layer, while the electron transport layer is located between the perovskite light-absorbing layer and the electrode. Therefore, before fabricating the SnOx thin film, the process includes depositing a hole transport layer on a substrate and then depositing a perovskite light-absorbing layer on the hole transport layer; the SnOx thin film is deposited on the surface of the perovskite light-absorbing layer.

[0012] For a formal (nip) structured titanium dioxide solar cell, the electron transport layer is located between the perovskite light-absorbing layer and the TCO conductive layer, while the hole transport layer is located between the perovskite light-absorbing layer and the electrode. Therefore, after forming the electron transport layer, the process includes depositing the perovskite light-absorbing layer on the electron transport layer and depositing the hole transport layer on the perovskite light-absorbing layer.

[0013] Furthermore, in the above-mentioned method for preparing perovskite solar cells, an atomic layer deposition process is used to deposit a SnOx thin film.

[0014] This design uses atomic layer deposition to prepare an extremely uniform, dense SnOx thin film with precisely controllable thickness. This provides a "precursor" film with consistent quality and controllable defect distribution for subsequent laser sintering, which is an important prerequisite for obtaining a high-performance electron transport layer and complements the laser sintering process.

[0015] Furthermore, in the above-mentioned method for preparing perovskite solar cells, the frequency of the infrared laser is 10 kHz to 100 kHz.

[0016] Laser scanning within this high-frequency range enables rapid, overlapping processing of thin film surfaces. This ensures the continuity of the sintering process, preventing omissions, and allows for precise control of the pulse interval of the energy input by controlling the frequency, which is beneficial for achieving a uniform and controllable heat treatment process.

[0017] Furthermore, in the above-mentioned method for preparing perovskite solar cells, an infrared laser is shaped and focused to form a square spot for scanning the SnOx thin film.

[0018] This design uses a square spot instead of a circular spot for scanning, which can eliminate the energy unevenness or "trajectory lines" that may be generated in the overlapping area of ​​the circular spot, and achieve uniform and complete heating treatment of the entire scanning area, thereby ensuring the consistency of the performance of large-area SnOx thin films.

[0019] In some embodiments, the hole transport layer can be a nickel oxide (NiOx) film or a spiro-OMeTAD film. These two materials are widely used hole transport layer options in perovskite solar cells. Combining them with the aforementioned laser-sintered optimized SnOx electron transport layer allows for the construction of a complete, high-performance charge transport channel. NiOx, as an inorganic hole transport material, exhibits good stability and is often suitable for pin structures; while spiro-OMeTAD, as a classic organic hole transport material, is more commonly used in nip structures.

[0020] Furthermore, the above-described method for fabricating perovskite solar cells also includes a step of preparing electrodes. This step completes the entire fabrication process of the perovskite solar cell, efficiently extracting the photocurrent generated inside the cell through the electrodes.

[0021] This invention also proposes a perovskite solar cell, comprising:

[0022] A substrate with a TCO conductive layer;

[0023] A hole transport layer, a perovskite light absorption layer, and an electron transport layer are stacked on a substrate;

[0024] The electron transport layer was prepared using the method described above.

[0025] This battery product directly benefits from the aforementioned preparation method. Its electron transport layer has high crystallinity, low defect density, and excellent interface characteristics, thus giving it significant advantages over batteries prepared using traditional methods (such as spin-coating C60 or unsintered ALD-SnOx) in terms of photoelectric conversion efficiency, open-circuit voltage, and long-term operational stability.

[0026] In some embodiments, the substrate is an FTO glass substrate, and the TCO conductive layer is an FTO layer on the surface of the FTO glass substrate. FTO (fluorine-doped tin oxide) glass has high light transmittance, excellent conductivity, and good thermal stability, providing an ideal light incident window and bottom electrode for the battery of the present invention, while being able to withstand the processing conditions of subsequent processes (especially laser sintering).

[0027] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0028] 1. After infrared laser sintering, the crystal quality of SnOx thin films is significantly improved, and the defect state density is reduced, resulting in higher electron mobility and a better energy level structure. This enables them to extract and transport photogenerated electrons more efficiently, while effectively blocking hole backflow, fundamentally improving the photoelectric conversion efficiency of the device;

[0029] 2. Laser sintering can promote the formation of a denser and less defective high-quality heterojunction interface between the SnOx thin film and the underlying perovskite active layer. This greatly suppresses nonradiative recombination at the interface, helps reduce the open-circuit voltage loss of the battery, and lays the foundation for obtaining higher efficiency.

[0030] 3. Compared with traditional organic electron transport materials such as C60, the SnOx thin film prepared by this invention has higher intrinsic mechanical strength, hardness and adhesion to the substrate. This makes the device less prone to film cracking or interlayer delamination under thermal cycling or mechanical stress, which significantly improves its physical reliability and long-term working stability.

[0031] 4. The SnOx thin film obtained by the synergistic effect of atomic layer deposition and laser sintering is extremely dense and can effectively block the penetration of external water vapor and oxygen, providing a solid protective barrier for the perovskite layer that is extremely sensitive to water and oxygen, thereby greatly extending the working life of the device.

[0032] 5. Laser sintering technology features highly concentrated energy and precise application area, enabling millisecond-level rapid temperature rise and fall. During this process, the overall temperature rise of the substrate is extremely low, completely avoiding thermal damage to heat-sensitive materials such as the underlying perovskite and hole transport layer caused by overall heating in traditional thermal annealing processes, thus ensuring the integrity of the device structure. Attached Figure Description

[0033] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0034] Figure 1 This is a schematic diagram of the inverted perovskite solar cell structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the formal perovskite solar cell structure of the present invention;

[0036] Figure 3 This is a schematic diagram of the fabrication process of the inverted perovskite solar cell of the present invention;

[0037] Figure 4 This is a schematic diagram of the fabrication process of the formal perovskite solar cell of this invention.

[0038] Figure label:

[0039] 10. Substrate; 20. TCO conductive layer; 30. Hole transport layer; 40. Perovskite light absorption layer; 50. Electron transport layer; 60. Electrode. Detailed Implementation

[0040] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and 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.

[0041] like Figures 1 to 4 As shown, this invention provides a method for fabricating perovskite solar cells, comprising the following steps:

[0042] A substrate 10 having a TCO conductive layer 20 is provided;

[0043] A stacked structure containing a SnOx thin film is formed on the substrate 10. SnOx is introduced as a candidate material for the electron transport layer 50. Its high electron mobility and good energy level matching can replace the traditional C60 and improve the potential efficiency and stability of the device.

[0044] The SnOx thin film was scanned and sintered using an infrared laser to form an electron transport layer 50.

[0045] This design utilizes the rapid, localized heating characteristics of infrared lasers to sinter SnOx thin films, effectively improving the crystal quality and reducing defects of the films without damaging the heat-sensitive underlying material, thereby significantly optimizing their electron transport performance.

[0046] like Figure 1 , 3 As shown, for a pin-structured perovskite solar cell, the hole transport layer 30 is located between the perovskite light-absorbing layer 40 and the TCO conductive layer 20, and the electron transport layer 50 is located between the perovskite light-absorbing layer 40 and the electrode 60. Therefore, the fabrication method of the perovskite solar cell includes the following steps:

[0047] S10. Provide a substrate 10, on which a TCO conductive layer 20 is formed. This step provides a basis for the formal structural device to have transparent conductive function.

[0048] S11. A hole transport layer 30 is deposited on the surface of the TCO conductive layer 20, and a perovskite light absorption layer 40 is deposited on the hole transport layer 30. This step constructs the core structure prototype of the inverted perovskite solar cell.

[0049] S12. A SnOx thin film is deposited on the surface of the perovskite light absorption layer 40. SnOx is introduced as a candidate material for the electron transport layer 50. Its high electron mobility and good energy level matching can replace the traditional C60 and improve the potential efficiency and stability of the device.

[0050] S13. The SnOx thin film is scanned and sintered using an infrared laser to form an electron transport layer 50.

[0051] like Figure 2 , 4 As shown, for a standard (nip) structured titanium dioxide solar cell, the electron transport layer 50 is located between the perovskite light-absorbing layer 40 and the TCO conductive layer 20, and the hole transport layer 30 is located between the perovskite light-absorbing layer 40 and the electrode 60. Therefore, the fabrication method of a perovskite solar cell includes the following steps:

[0052] S20. Provide a substrate 10, on which a TCO conductive layer 20 is formed. This step provides a basis for the formal structural device to have transparent conductive function.

[0053] S21. A SnOx thin film is deposited on the surface of the TCO conductive layer 20. The high electron mobility of SnOx and good interfacial contact with TCO are utilized to improve the electron transport efficiency.

[0054] S22. The SnOx thin film is scanned and sintered using an infrared laser to form an electron transport layer 50.

[0055] S23. A perovskite light-absorbing layer 40 is deposited on the electron transport layer 50, and a hole transport layer 30 is deposited on the perovskite light-absorbing layer 40. This step constructs the core structure prototype of a formal perovskite solar cell.

[0056] Based on laser sintering technology, the preferred method is to deposit SnOx thin films using atomic layer deposition (ALD). The core of ALD lies in the alternating, pulsed introduction of precursor gases (raw materials) required for film growth into the reaction chamber, introducing one precursor at a time, followed by purging with an inert gas. Each precursor reacts chemically with the substrate surface, forming a single atomic layer before automatically stopping, thus achieving precise, layer-by-layer film growth.

[0057] This design utilizes atomic layer deposition (ALD) to fabricate extremely uniform, dense, and precisely controllable SnOx films. This provides a consistent and defect-distributed precursor film for subsequent laser sintering, a crucial prerequisite for obtaining a high-performance electron transport layer, and complements the advantages of laser sintering. Most importantly, ALD processes are typically performed at relatively low temperatures (e.g., 80°C - 150°C), perfectly compatible with heat-sensitive structures such as the perovskite light-absorbing layer 40 and hole transport layer 30, avoiding thermal damage during deposition.

[0058] Based on laser sintering technology, the preferred approach is to use an infrared laser with a frequency of 10kHz to 100kHz. Laser scanning within this high-frequency range enables rapid, overlapping processing of the thin film surface. This ensures the continuity of the sintering process, preventing omissions, and allows for precise control of the energy input pulse interval through frequency control, facilitating a uniform and controllable heat treatment process. More importantly, at this frequency, combined with an appropriate scanning speed, laser energy can act on the SnOx thin film surface in a "rapid heating and rapid cooling" manner. This promotes sufficient crystallization and defect repair of the thin film material, effectively controls the depth of the heat-affected zone, and prevents excessive heat accumulation and diffusion to the underlying heat-sensitive material. Thus, while optimizing the performance of the electron transport layer 50, the safety of the underlying functional structure is ensured.

[0059] It should be noted that the output power of the infrared laser is adjustable, and the sintering energy can be adjusted according to the specific thickness, initial state, and desired crystallinity of the SnOx film. Specifically, lower power can be used for ultrathin films or for slight surface annealing to avoid over-processing; while higher power ensures sufficient energy input for thicker films or areas where higher crystallinity is desired. By adjusting the laser power and coordinating it with parameters such as scanning speed and spot size, the energy density acting on a unit area of ​​the film can be controlled. This effectively drives SnOx grain growth, repairs defects to obtain excellent electrical properties, while confining the thermal impact to the film surface. After scanning, the substrate temperature is relatively low (around 60℃-80℃), absolutely avoiding the possibility of breaking through the film or damaging the underlying heat-sensitive material due to excessive energy.

[0060] In some embodiments of the present invention, the wavelength range of the infrared laser is preferably 900 nm to 1100 nm, which falls within the near-infrared band. SnOx materials have good absorption rates for this wavelength of laser, enabling efficient photo-thermal conversion. Simultaneously, this wavelength of laser has minimal thermal impact on the underlying perovskite and other materials, allowing for selective heating and protection of the underlying functional layer.

[0061] To improve the fabrication quality of the electron transport layer 50, an infrared laser is shaped and focused to form a square spot for scanning the SnOx thin film. Compared to the potential energy overlap or omissions that may occur at the overlap points of the scanning path caused by traditional circular spots, square spots can achieve seamless scanning trajectories, thereby applying a highly uniform energy distribution throughout the entire processing area.

[0062] In some embodiments of the present invention, the hole transport layer 30 may be a nickel oxide (NiOx) thin film or a spiro-OMeTAD thin film. These two materials are widely used hole transport layer options in perovskite solar cells. Combining them with the aforementioned laser-sintered optimized SnOx electron transport layer enables the construction of a complete, high-performance charge transport channel. NiOx, as an inorganic hole transport material, exhibits good stability and is often suitable for inverted (pin) structures; while spiro-OMeTAD, as a classic organic hole transport material, is more commonly used in nip structures.

[0063] like Figure 3 , 4 As shown, the above-mentioned method for fabricating perovskite solar cells also includes a step of preparing electrodes. This step completes the entire fabrication process of the perovskite solar cell, efficiently extracting the photocurrent generated inside the cell through the electrodes. Specifically, as... Figure 3 As shown, for a pin-structured perovskite solar cell, the fabrication method further includes: step S14, fabricating an electrode 60 on the electron transport layer 50. For example... Figure 4 As shown, for a formal (nip) structured titanium dioxide solar cell, the perovskite solar cell fabrication method further includes: step S24, fabricating an electrode 60 on the hole transport layer 30.

[0064] like Figure 1 , 2 As shown, this invention also proposes a perovskite solar cell, comprising: a substrate 10 having a TCO conductive layer 20, wherein a hole transport layer 30, a perovskite light-absorbing layer 40, and an electron transport layer 50 are stacked on the substrate 10, and the electron transport layer 50 is prepared by the method described above. In this document, "stacked" refers only to the stacking of functional layers (such as the TCO layer, transport layer, etc.) and does not include a specific order between the layers.

[0065] This battery product directly benefits from the above-mentioned preparation method. Its electron transport layer 50 has high crystallinity, low defect density and excellent interface characteristics, which makes the battery significantly superior to batteries prepared by traditional methods (such as spin-coating C60 or unsintered ALD-SnOx) in terms of photoelectric conversion efficiency, open-circuit voltage and long-term working stability.

[0066] In some embodiments, the substrate 10 is an FTO glass substrate, and the TCO conductive layer 20 is an FTO layer on the surface of the FTO glass substrate. FTO (fluorine-doped tin oxide) glass has high light transmittance, excellent conductivity and good thermal stability, providing an ideal light incident window and bottom electrode for the battery of the present invention, while being able to withstand the processing conditions of subsequent processes (especially laser sintering).

[0067] like Figure 1 As shown, for a pin-structured perovskite solar cell, a TCO conductive layer 20, a hole transport layer 30, a perovskite light-absorbing layer 40, and an electron transport layer 50 are sequentially formed on the substrate 10. Figure 2 As shown, for a standard (nip) structured titanium dioxide solar cell, a TCO conductive layer 20, an electron transport layer 50, a perovskite light absorption layer 40, and a hole transport layer 30 are sequentially formed on the substrate 10.

[0068] For ease of understanding, the preparation method of this invention is selected as the experimental group, and the conventional hot annealing process is selected as the control group for comparison and explanation.

[0069] Experimental Example 1 – Inverted Perovskite Solar Cell

[0070] Using a 1.5cm × 2.5cm FTO conductive glass substrate 10, a NiOx hole transport layer 30, a perovskite light absorption layer 40, and a SnOx thin film with a thickness of approximately 20nm were sequentially prepared. Subsequently, the SnOx thin film was subjected to scanning sintering treatment using an infrared laser. The treatment parameters were: laser rated power 500W, operating frequency 10kHz, output power ratio 12%, scanning pattern of "bow" shape with a filling spacing of 0.16mm, and scanning speed of 1000mm / s. After the treatment, silver electrodes were deposited by vapor deposition. Finally, the device was fabricated and its photoelectric conversion efficiency was tested. The test results are shown in Table 1 below.

[0071]

[0072] Table 1

[0073] Experimental Example 2 – Formal Perovskite Solar Cell

[0074] Using an FTO conductive glass substrate with dimensions of 1.5cm × 2.5cm as 10, a SnOx thin film with a thickness of approximately 20nm was prepared by atomic layer deposition. Subsequently, it was subjected to scanning sintering using an infrared laser with the following parameters: laser rated power of 500W, operating frequency of 10kHz, output power ratio of 18%, scanning filling pattern of "bow" shape, filling spacing of 0.16mm, and scanning speed of 1000mm / s. After sintering, a perovskite light absorption layer 40 and a spiro-OMeTAD hole transport layer 30 were deposited sequentially, and a gold electrode was deposited on the top layer. Finally, the device was fabricated and its photoelectric conversion efficiency was tested. The test results are shown in Table 2 below.

[0075]

[0076] Table 2

[0077] Experimental Example 3 – Inverted Perovskite Solar Cell

[0078] Using a 30cm×30cm FTO conductive glass substrate 10, a NiOx hole transport layer 30, a perovskite light absorption layer 40, and a SnOx thin film with a thickness of approximately 20nm were sequentially prepared. Subsequently, the SnOx thin film was simultaneously processed by galvanometer scanning using two infrared lasers. The processing parameters were: laser rated power of 500W, operating frequency of 40kHz, output power ratio of 15%, scanning pattern of "bow" shaped filling with a filling spacing of 0.16mm, and scanning speed of 1000mm / s. After processing, copper electrodes were deposited, and the device fabrication was completed. Its photoelectric conversion efficiency was then tested, and the test results are shown in Table 3 below.

[0079]

[0080] Table 3

[0081] Experimental Example 4 – Inverted Perovskite Solar Cell

[0082] Using a 30cm×30cm FTO conductive glass substrate 10, a NiOx hole transport layer 30, a perovskite light absorption layer 40, and a SnOx thin film with a thickness of approximately 20nm were sequentially prepared. Subsequently, the SnOx thin film was subjected to scanning sintering treatment using an infrared laser. The treatment parameters were: laser rated power 3000W, operating frequency 100kHz, output power ratio 45%, scanning pattern of "bow" shaped filling with a filling spacing of 0.3mm, and scanning speed of 4500mm / s. After the treatment, a copper electrode was deposited, and the device fabrication was completed. Its photoelectric conversion efficiency was then tested, and the test results are shown in Table 4 below.

[0083]

[0084] Table 4

[0085] Comparison Example

[0086] A 30cm×30cm FTO conductive glass was selected as the substrate 10. A NiOx hole transport layer 30, a perovskite light absorption layer 40, and a SnOx thin film with a thickness of about 20nm were prepared sequentially. The SnOx thin film was then post-treated by thermal annealing, and a copper electrode was prepared on its surface. Finally, the device was integrated and its photoelectric conversion efficiency was tested. The test results are shown in Table 5 below.

[0087]

[0088] Table 5

[0089] Experimental data comparison revealed that the perovskite solar cells (experimental group) prepared using this invention exhibited an average photoelectric conversion efficiency consistently above 18%, significantly outperforming the control group devices (average efficiency approximately 13%) processed using conventional thermal annealing. This represents an absolute efficiency increase of over 5 percentage points and a relative improvement of over 38%. This significant performance gain directly validates the superiority of replacing "overall thermal annealing" with "infrared laser scanning sintering" for processing the SnOx electron transport layer.

[0090] The laser sintering process used in this invention can rapidly crystallize and repair defects in SnOx films within milliseconds through a fast and localized energy deposition method, thereby significantly improving electron mobility and interface quality. At the same time, this process can control the overall temperature rise of the substrate at a low level, effectively avoiding the damage caused to heat-sensitive materials such as perovskite light absorption layer and hole transport layer by traditional high-temperature long-term thermal annealing, and ensuring the integrity of the device structure.

[0091] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments of the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific order is expressly specified, and as long as the output of a previous process is not used in a subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0092] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fabricating perovskite solar cells, characterized in that, Includes the following steps: Provide a substrate with a TCO conductive layer; A stacked structure containing a SnOx thin film is formed on the substrate; The SnOx thin film is scanned and sintered using an infrared laser to form an electron transport layer.

2. The method for preparing perovskite solar cells according to claim 1, characterized in that, Before preparing the SnOx thin film, the method further includes the steps of depositing a hole transport layer on the substrate and depositing a perovskite light absorption layer on the hole transport layer; the SnOx thin film is deposited on the surface of the perovskite light absorption layer.

3. The method for preparing perovskite solar cells according to claim 1, characterized in that, After forming the electron transport layer, the method further includes the steps of depositing a perovskite light absorption layer on the electron transport layer and depositing a hole transport layer on the perovskite light absorption layer.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The SnOx thin film was prepared using atomic layer deposition (ALD).

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The frequency of the infrared laser is from 10 kHz to 100 kHz.

6. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The infrared laser, after being shaped and focused, forms a square spot to scan the SnOx thin film.

7. The method for preparing a perovskite solar cell according to any one of claims 1 to 6, characterized in that, The hole transport layer includes a NiOx thin film or a spiro-OMeTAD thin film.

8. The method for preparing a perovskite solar cell according to any one of claims 1 to 6, characterized in that, It also includes the step of preparing electrodes.

9. A perovskite solar cell, characterized in that, include: A substrate with a TCO conductive layer; A hole transport layer, a perovskite light absorption layer, and an electron transport layer are stacked on the substrate; The electron transport layer is prepared by the method described in any one of claims 1 to 8.

10. The perovskite solar cell according to claim 9, characterized in that, The substrate is an FTO glass substrate, and the TCO conductive layer is an FTO layer on the surface of the FTO glass substrate.

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