High-efficiency flexible perovskite solar cell based on laser annealing technology and preparation method thereof

Abstract

The invention relates to an efficient flexible perovskite solar cell based on a laser annealing technology and a preparation method of the efficient flexible perovskite solar cell. The efficient flexible perovskite solar cell comprises a flexible substrate, a metal oxide electron transport layer, a perovskite light absorption layer, a hole transport layer and a metal back electrode. Wherein the perovskite light absorption layer is formed by crystallization through a laser annealing technology. The perovskite thin film is irradiated through the high-energy laser beam, rapid crystallization is achieved, the annealing process can be completed in a short time, the temperature gradient and the heating rate can be accurately controlled, efficient crystallization is achieved at the low temperature, and therefore the crystallization quality of perovskite is optimized. The laser annealing can avoid the damage to the material caused by long-time high-temperature treatment, improves the production efficiency, is very important for maintaining the integrity and stability of the flexible substrate, also can form a uniform perovskite thin film on the flexible substrate, improves the performance of the cell, and prolongs the service life of the cell.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, specifically relating to a high-efficiency flexible perovskite solar cell based on laser annealing technology and its preparation method. Background Technology

[0002] With the rapid development of modern technology, perovskite solar cells have become a shining star in the new energy field due to their advantages such as high efficiency, low cost, and ease of fabrication. In the fabrication of flexible perovskite solar cells, methods such as solution processing and spin coating are commonly used to prepare the perovskite light-absorbing layer. In existing technologies, a long-term, high-temperature thermal annealing process is required to obtain the ideal perovskite light-absorbing layer film. However, the perovskite light-absorbing layer film prepared by this high-temperature annealing and rapid crystallization method has a large number of defects in the bulk, grain boundaries, and interfaces, which is detrimental to the photovoltaic performance and stability of perovskite solar cells. It is worth noting that the traditional thermal annealing process requires a temperature of at least 150°C, which can damage the flexible substrate and is not conducive to the fabrication of flexible devices. At the same time, the traditional heat treatment process requires a holding time of about 1 hour, resulting in low yield and high energy consumption, which does not meet the requirements of sustainable green development. Therefore, how to develop a low-temperature, rapid processing method for perovskite light-absorbing layers has become an urgent technical problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to provide a high-efficiency flexible perovskite solar cell based on laser annealing technology and its preparation method in order to solve the above-mentioned problems.

[0004] The present invention achieves the above objectives through the following technical solutions: This invention provides a high-efficiency flexible perovskite solar cell based on laser annealing technology. The high-efficiency flexible perovskite solar cell includes a flexible substrate, a metal oxide electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal back electrode. The perovskite light-absorbing layer is formed by spin-coating a perovskite precursor solution to form a pretreated perovskite film, and then crystallizing the pretreated perovskite film using laser annealing technology.

[0005] As a further optimization of the present invention, the high-efficiency flexible perovskite solar cell includes a formal structure or an inverse structure high-efficiency flexible perovskite solar cell. The high-efficiency flexible perovskite solar cell with the formal structure includes a flexible substrate, a metal oxide electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal back electrode stacked sequentially. The high-efficiency flexible perovskite solar cell with an inverted structure comprises a flexible substrate, a hole transport layer, a perovskite light-absorbing layer, a metal oxide electron transport layer, and a metal back electrode, which are stacked sequentially.

[0006] As a further optimization of the present invention, the flexible substrate includes polyethylene terephthalate (PET) or polyimide (PI).

[0007] As a further optimization of the present invention, the perovskite precursor solution is prepared by dissolving PbI2, CsI, CH3NH3I, and MACl in DMF and DMSO solutions to obtain (CH3NH3). 0.9 Cs 0.1 PbI3; Alternatively, PbI2 can be dissolved in DMF and DMSO solutions to prepare a PbI2 solution; CH3NH3I and MACl can be dissolved in isopropanol to prepare a FAI solution. When using PbI2 solution and FAI solution to prepare perovskite films, the PbI2 solution is spin-coated first, followed by the FAI solution.

[0008] As a further optimization of the present invention, the laser annealing technology involves using a high-energy laser beam to irradiate the pretreated perovskite film to complete the crystallization process. The laser wavelength is 400-800 nm, and the power density is 0.1-10 W / cm². 2 The scanning speed is 10-100 mm / s, and the temperature is 25-150℃.

[0009] This invention also provides a method for fabricating a high-efficiency flexible perovskite solar cell based on laser annealing technology, comprising the following steps: Step 1: Provide a flexible substrate and form a metal oxide electron transport layer or hole transport layer on the flexible substrate; Step 2: Spin-coat a perovskite precursor solution onto a metal oxide electron transport layer or hole transport layer to form a pretreated perovskite film. Then, use laser annealing technology to crystallize the pretreated perovskite film to form a perovskite light absorption layer. Step 3: Form a metal oxide electron transport layer or hole transport layer on the perovskite light absorption layer; Step 4: Deposit a metal back electrode on the metal oxide electron transport layer or hole transport layer, and then encapsulate it to obtain a flexible perovskite solar cell.

[0010] As a further optimization of the present invention, in steps one and three, SnO2 is spin-coated or grown in a water bath on a flexible substrate or perovskite light-absorbing layer, or C60 is thermally evaporated to form a metal oxide electron transport layer, and Spiro-OMeTAD solution is spin-coated or NiO is spin-coated on a flexible substrate or perovskite light-absorbing layer to form a hole transport layer.

[0011] As a further optimization of the present invention, in step three, a layer of silver is deposited on the metal oxide electron transport layer or hole transport layer as a metal back electrode by thermal evaporation.

[0012] The beneficial effects of this invention are as follows: This invention discloses a rapid and precise crystallization process achieved by irradiating perovskite thin films with a high-energy laser beam, avoiding the damage to flexible substrates caused by traditional high-temperature annealing. This method not only improves production efficiency but also optimizes the performance and lifespan of the cells. This invention compares the performance of perovskite thin films and devices after high-energy laser annealing and conventional heating stage annealing under various conditions, including: formal structure, inverse structure, one-step perovskite preparation method, and two-step perovskite preparation method. Experimental results show that the flexible perovskite thin film after laser annealing has better quality and crystallinity, and the performance of the obtained flexible perovskite solar cells is significantly improved, demonstrating that laser annealing technology has broad application prospects in the production of flexible perovskite solar cells. Attached Figure Description

[0013] Figure 1 This is a structural diagram of the high-efficiency flexible perovskite solar cell of the formal structure of this invention.

[0014] Figure 2 This is a structural diagram of the high-efficiency flexible perovskite solar cell with an inverted structure according to the present invention.

[0015] Figure 3 These are SEM images of the perovskite light-absorbing layer surfaces of Comparative Example 1(a) and Example 1(b) of the present invention.

[0016] Figure 4 These are comparative examples 1(a) and example 1(b) of the present invention, showing the state of the flexible substrates after conventional heating table annealing and laser annealing.

[0017] Figure 5 These are voltage and current density performance graphs of the high-efficiency flexible perovskite solar cells of Comparative Examples 1-4 and Examples 1-4 of the present invention.

[0018] Figure 6 These are PCE box plots of the high-efficiency flexible perovskite solar cells of Comparative Examples 1-4 and Examples 1-4 of the present invention.

[0019] Figure 7 This is the MPPT efficiency stability diagram of the high-efficiency flexible perovskite solar cells of Comparative Example 1 and Example 4 of the present invention.

[0020] Figure 8 This is a graph showing the mechanical efficiency stability of the high-efficiency flexible perovskite solar cells of Comparative Example 1 and Example 1 of the present invention. Detailed Implementation

[0021] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0022] Example 1 In this embodiment, the preparation is as follows Figure 1 The high-efficiency flexible perovskite solar cell with the formal structure shown comprises a flexible substrate, an electron transport layer (metal oxide electron transport layer), a perovskite light absorption layer, a hole transport layer, and a metal back electrode, which are stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the electron transport layer: A SnO2 electron transport layer was prepared by chemical bath deposition (CBD). First, a SnCl2-2H2O mother liquor was prepared. 4.2g of urea was dissolved in 400mL of deionized water, and then 100µL of mercaptoacetic acid and 4mL of HCl (37wt%) were added. The solution was thoroughly shaken and mixed, and then placed in a refrigerator to stand for three days. Then, 200µL of the settled SnCl2·2H2O mother liquor was mixed with 100mL of deionized water to prepare a 0.02M dilution. The flexible substrate treated in step S1 was then immersed in the prepared dilution and placed in a 60℃ oven for 1 hour to allow for a full reaction. After that, the substrate was repeatedly rinsed with deionized water until the rinsing solution was clear and transparent. The substrate was then dried with an air gun. Finally, the substrate was annealed on a 150℃ heating stage for 1 hour to obtain the electron transport layer. S3. Preparation of the perovskite light-absorbing layer: 483 mg PbI2, 23 mg CsI, 181 mg CH3NH3I, and 20 mg MACl were dissolved in a DMF:DMSO = 4:1 solution to prepare (CH3NH3). 0.9 Cs 0.1 PbI3 solution (50 µL) was then spin-coated onto the electron transport layer obtained in step S2 at 4000 rpm for 60 seconds in air. The resulting perovskite was then laser-annealed using a fast laser annealing apparatus. The specific steps were as follows: first, the laser was turned on and preheated for at least 10 minutes. After preheating, the substrate was placed on a displacement platform. Then, the laser scanning path and area were set. The optimal annealing conditions for the fast laser apparatus were set as follows: wavelength 533 nm, power density: 8 W / cm². 2The scanning speed was 2.5 mm; finally, a perovskite thin film (i.e., perovskite light-absorbing layer) with a thickness of about 600 nm was prepared on the surface of the electron transport layer. S4. Preparation of the hole transport layer: Before preparing the hole transport layer solution, it is necessary to prepare the mother liquor of lithium salt and FK209. Preparation of lithium salt mother liquor: Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 mL of acetonitrile (ACN), stir at room temperature for 2 h until dissolved to obtain lithium salt solution; Preparation of FK209 stock solution: Add 450mg of FK209 powder to 1mL of acetonitrile (ACN), and stir at room temperature for 2h on a magnetic stirrer until dissolved to obtain FK209 solution; Hole transport layer solution preparation: Weigh 82 mg Spiro-OMeTAD, 17.5 µL FK209 solution, 18 µL lithium salt, 25.6 µL TBP solution and 1 mL chlorobenzene and add them to a 3 mL glass bottle to prepare the Spiro-OMeTAD hole transport layer solution. Then take 50 µL of the solution and spin it at 45000 rpm for 30 s to dynamically spin-coat the solution onto the perovskite film prepared in step S3 to prepare the hole transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the hole transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (<1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0023] Example 2 In this embodiment, the preparation is as follows Figure 1 The high-efficiency flexible perovskite solar cell with the formal structure shown is an inverted high-efficiency flexible perovskite solar cell comprising a flexible substrate, an electron transport layer (metal oxide electron transport layer), a perovskite light absorption layer, a hole transport layer, and a metal back electrode stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the electron transport layer: SnO2 nanoparticles were spin-coated using a solution method to form the electron transport layer. First, 1 ml of a 15% SnO2 hydrocolloid dispersion was placed in 5 ml of deionized water and sonicated for 2 h. Then, the dispersion was spin-coated onto the flexible substrate treated in step S1 at a speed of 3000 rpm for 60 s. Finally, the sample was placed on a heating stage at 180°C and annealed for 1 h to remove the solvent and solidify the electron transport layer. S3. Preparation of the perovskite light-absorbing layer: 1449 mg PbI2 was dissolved in 2 ml of DMF:DMSO = 4:1 solution and heated to 50 °C with stirring for 2 h to obtain a PbI2 solution. Then, 181 mg CH3NH3I and 20 mg MACl were added to 2 ml of isopropanol (IPA) and stirred for 2 h to obtain a FAI solution. During preparation, 60 µL of PbI2 solution was spin-coated at 1500 rpm for 30 s under nitrogen atmosphere onto the surface of the electron transport layer prepared in step S2. Then, 90 µL of FAI solution was spin-coated at 2000 rpm for 30 s under air atmosphere. The obtained perovskite was then laser-annealed using a fast laser annealing instrument. The specific steps were as follows: First, the laser was turned on and preheated for at least 10 min. After preheating, the substrate was placed on the displacement platform, and then the laser scanning path and area were set. The optimal annealing conditions for the fast laser instrument were set as follows: wavelength 533 nm, power density: 8 W / cm². 2 With a scanning speed of 2.5 mm, a perovskite thin film with a thickness of approximately 600 nm was finally obtained. S4. Preparation of the hole transport layer: Before preparing the hole transport layer solution, it is necessary to prepare the mother liquor of lithium salt and FK209. Preparation of lithium salt mother liquor: Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 mL of acetonitrile (ACN), stir at room temperature for 2 h until dissolved to obtain lithium salt solution; Preparation of FK209 stock solution: Add 450mg of FK209 powder to 1mL of acetonitrile (ACN), and stir at room temperature for 2h on a magnetic stirrer until dissolved to obtain FK209 solution; Hole transport layer solution preparation: Weigh 82 mg Spiro-OMeTAD, 17.5 µL FK209 solution, 18 µL lithium salt, 25.6 µL TBP solution and 1 mL chlorobenzene and add them to a 3 mL glass bottle to prepare the Spiro-OMeTAD hole transport layer solution. Then take 50 µL of the solution and spin it at 45000 rpm for 30 s to dynamically spin-coat the solution onto the perovskite film prepared in step S3 to prepare the hole transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the hole transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (<1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0024] Example 3 In this embodiment, the preparation is as follows Figure 2 The high-efficiency flexible perovskite solar cell with an inverted structure shown comprises a flexible substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer (metal oxide electron transport layer), and a metal back electrode, which are stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the hole transport layer: A NiO thin film was prepared as the hole transport layer using magnetron sputtering. The flexible substrate prepared in step S1 was placed in the magnetron sputtering cavity, and the vacuum level was evacuated to 1.0 × 10⁻⁶. -6 Sputtering deposition began at Pa, with the following conditions: temperature: 150℃, power: 100W, cavity pressure: 0.9Pa, oxygen-argon ratio: O2:Ar=9:1, and sputtering time: 5min. Finally, a NiO film with a thickness of 30nm was obtained, which served as the hole transport layer for the perovskite solar cell. S3. Preparation of the perovskite light-absorbing layer: 483 mg PbI2, 23 mg CsI, 181 mg CH3NH3I, and 20 mg MACl were dissolved in a DMF:DMSO = 4:1 solution to prepare (CH3NH3). 0.9 Cs 0.1 PbI3 solution (50 µL) was then spin-coated onto the hole transport layer obtained in step S2 at 4000 rpm for 60 seconds in air. The resulting perovskite was then laser-annealed using a fast laser annealing apparatus. The specific steps were as follows: First, the laser was turned on and preheated for at least 10 minutes. After preheating, the substrate was placed on a displacement platform. Then, the laser scanning path and area were set. The optimal annealing conditions for the fast laser apparatus were set as follows: wavelength 533 nm, power density: 8 W / cm². 2 With a scanning speed of 2.5 mm, a perovskite thin film with a thickness of approximately 600 nm was finally obtained. S4. Preparation of the electron transport layer: C60 is deposited on the perovskite light-absorbing layer obtained in step S3 by thermal evaporation. The flexible substrate prepared in step S3 is placed in the magnetron sputtering cavity, and the vacuum level is evacuated to 1.0 × 10⁻⁶. -5 Evaporation was started at Pa, the evaporation rate was controlled at 0.125 nm / s, and the evaporation time was 8 min, resulting in a C60 thin film with a thickness of 30 nm as an electron transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the electron transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (< 1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0025] Example 4 In this embodiment, the preparation is as follows Figure 2 The high-efficiency flexible perovskite solar cell with an inverted structure shown comprises a flexible substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer (metal oxide electron transport layer), and a metal back electrode, which are stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the hole transport layer: A NiO thin film was prepared as the hole transport layer using magnetron sputtering. The flexible substrate prepared in step S1 was placed in the magnetron sputtering cavity, and the vacuum level was evacuated to 1.0 × 10⁻⁶. -6 Sputtering deposition began at Pa, with the following conditions: temperature: 150℃, power: 100W, cavity pressure: 0.9Pa, oxygen-argon ratio: O2:Ar=9:1, and sputtering time: 5min. Finally, a NiO film with a thickness of 30nm was obtained, which served as the hole transport layer for the perovskite solar cell. S3. Preparation of the perovskite light-absorbing layer: 1449 mg PbI2 was dissolved in 2 ml of DMF:DMSO = 4:1 solution and heated to 50°C with stirring for 2 h to obtain a PbI2 solution. Then, 181 mg CH3NH3I and 20 mg MACl were added to 2 ml of isopropanol (IPA) and stirred for 2 h to obtain a FAI solution. During preparation: 60 µL of PbI2 solution was spin-coated onto the hole transport layer obtained in step S2 under nitrogen atmosphere with spin-coating parameters of 1500 rpm for 30 s. Then, 90 µL of FAI solution was spin-coated under air atmosphere with spin-coating parameters of 2000 rpm for 30 s. The obtained perovskite was then laser-annealed using a fast laser annealing instrument. The specific steps were as follows: First, the laser was turned on and preheated for at least 10 min. After preheating, the substrate was placed on the displacement platform, and then the laser scanning path and area were set. The optimal annealing conditions of the fast laser instrument were set as follows: wavelength 533 nm, power density: 8 W / cm². 2 With a scanning speed of 2.5 mm, a perovskite thin film with a thickness of approximately 600 nm was finally obtained. S4. Fabrication of the electron transport layer: C60 is deposited on the perovskite light-absorbing layer by thermal evaporation. The flexible substrate prepared in step S3 is placed in the magnetron sputtering cavity, and the vacuum level is evacuated to 1.0 × 10⁻⁶. -5 Evaporation was started at Pa, the evaporation rate was controlled at 0.125 nm / s, and the evaporation time was 8 min, resulting in a C60 thin film with a thickness of 30 nm as an electron transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the electron transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (< 1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0026] Comparative Example 1 In this comparative example, the preparation is as follows: Figure 1 The high-efficiency flexible perovskite solar cell with the formal structure shown is an inverted high-efficiency flexible perovskite solar cell comprising a flexible substrate, an electron transport layer (metal oxide electron transport layer), a perovskite light absorption layer, a hole transport layer, and a metal back electrode stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the electron transport layer: A SnO2 electron transport layer was prepared by chemical bath deposition (CBD). First, a SnCl2-2H2O mother solution was prepared. 4.2g of urea was dissolved in 400mL of deionized water, and then 100µL of mercaptoacetic acid and 4mL of HCl (37wt%) were added. The solution was thoroughly shaken and mixed, and then placed in a refrigerator to stand for three days. Then, 200µL of the settled SnCl2·2H2O mother solution was mixed with 100mL of deionized water to prepare a 0.02M dilution. The flexible substrate treated in step S1 was then immersed in the prepared dilution and placed in a 60℃ oven for 1 hour to allow for a full reaction. After that, the substrate was repeatedly rinsed with deionized water until the rinsing solution was clear and transparent. The substrate was then dried with an air gun. Finally, the substrate was annealed on a 150℃ heating stage for 1 hour to obtain the electron transport layer. S3. Preparation of the perovskite light-absorbing layer: 483 mg PbI2, 23 mg CsI, 181 mg CH3NH3I, and 20 mg MACl were dissolved in a DMF:DMSO = 4:1 solution to prepare (CH3NH3). 0.9 Cs 0.1 PbI3 was then used to spin coat the electron transport layer obtained in step S2 onto the surface of the electron transport layer at 4000 rpm for 60 s in air. The coating was then annealed at 100 °C for 1 min and then at 150 °C for 10 min to obtain a perovskite film (i.e., perovskite light-absorbing layer) with a thickness of about 600 nm. S4. Preparation of the hole transport layer: Before preparing the hole transport layer solution, it is necessary to prepare the mother liquor of lithium salt and FK209. Preparation of lithium salt mother liquor: Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 mL of acetonitrile (ACN), stir at room temperature for 2 h until dissolved to obtain lithium salt solution; Preparation of FK209 stock solution: Add 450mg of FK209 powder to 1mL of acetonitrile (ACN), and stir at room temperature for 2h on a magnetic stirrer until dissolved to obtain FK209 solution; Hole transport layer solution: Weigh 82 mg Spiro-OMeTAD, 17.5 µL FK209 solution, 18 µL lithium salt, 25.6 µL LBP solution and 1 mL chlorobenzene and add them to a 3 mL glass bottle to prepare the Spiro-OMeTAD hole transport layer solution. Then take 50 µL of the solution and spin it at 45000 rpm for 30 s to dynamically spin-coat the solution onto the perovskite film prepared in step S3 to prepare the hole transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the hole transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (<1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0027] Comparative Example 2 In this comparative example, the preparation is as follows: Figure 1 The high-efficiency flexible perovskite solar cell with the formal structure shown is an inverted high-efficiency flexible perovskite solar cell comprising a flexible substrate, an electron transport layer (metal oxide electron transport layer), a perovskite light absorption layer, a hole transport layer, and a metal back electrode stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the electron transport layer: SnO2 nanoparticles were spin-coated using a solution method to form the electron transport layer. First, 1 ml of a 15% SnO2 hydrocolloid dispersion was placed in 5 ml of a deionized water solution and sonicated for 2 h. Then, the dispersion was spin-coated onto the flexible substrate treated in step S1 at a speed of 3000 rpm for 60 s. Finally, the sample was placed on a heating stage at 180°C and annealed for 1 h to remove the solvent and solidify the electron transport layer. S3. Preparation of the perovskite light-absorbing layer: 1449 mg PbI2 was dissolved in 2 ml of DMF:DMSO=4:1 solution and heated to 50 °C and stirred for 2 h to obtain a PbI2 solution. Then, 181 mg CH3NH3I and 20 mg MACl were added to 2 ml of isopropanol (IPA) and stirred for 2 h to obtain a FAI solution. During preparation: 60 µL of PbI2 solution was spin-coated on the surface of the electron transport layer obtained in step S2 under nitrogen atmosphere with a spin-coating parameter of 1500 rpm for 30 s. Then, 90 µL of FAI solution was spin-coated in air atmosphere with a spin-coating parameter of 2000 rpm for 30 s. Finally, the layer was annealed at 150 °C for 15 min to obtain a perovskite film with a thickness of approximately 600 nm. S4. Preparation of the hole transport layer: Before preparing the hole transport layer solution, it is necessary to prepare the mother liquor of lithium salt and FK209. Preparation of lithium salt mother liquor: Add 520 mg of lithium bis(trifluoromethanesulfonyl)imide powder to 1 mL of acetonitrile (ACN), stir at room temperature for 2 h until dissolved to obtain lithium salt solution; Preparation of FK209 stock solution: Add 450mg of FK209 powder to 1mL of acetonitrile (ACN), and stir at room temperature for 2h on a magnetic stirrer until dissolved to obtain FK209 solution; Hole transport layer solution preparation: Weigh 82 mg Spiro-OMeTAD, 17.5 µL FK209 solution, 18 µL lithium salt, 25.6 µL TBP solution and 1 mL chlorobenzene and add them to a 3 mL glass bottle to prepare the Spiro-OMeTAD hole transport layer solution. Then take 50 µL of the solution and spin it at 45000 rpm for 30 s to dynamically spin-coat the solution onto the perovskite film prepared in step S3 to prepare the hole transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the hole transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (<1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0028] Comparative Example 3 In this comparative example, the preparation was as follows Figure 2 The high-efficiency flexible perovskite solar cell with an inverted structure shown comprises a flexible substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer (metal oxide electron transport layer), and a metal back electrode, which are stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the hole transport layer: A NiO thin film was prepared as the hole transport layer using magnetron sputtering. The flexible substrate prepared in step S1 was placed in the magnetron sputtering cavity, and the vacuum level was evacuated to 1.0 × 10⁻⁶. -6 Sputtering deposition began at Pa, with the following conditions: temperature: 150℃, power: 100W, cavity pressure: 0.9Pa, oxygen-argon ratio: O2:Ar=9:1, and sputtering time: 5min. Finally, a NiO film with a thickness of 30nm was obtained, which served as the hole transport layer for the perovskite solar cell. S3. Preparation of the perovskite light-absorbing layer: 483 mg PbI2, 23 mg CsI, 181 mg CH3NH3I, and 20 mg MACl were dissolved in a DMF:DMSO = 4:1 solution to prepare (CH3NH3). 0.9 Cs 0.1PbI3 was then used to spin-coat 50 µL of the solution onto the hole transport layer obtained in step S2 in an air environment at a spin-coating parameter of 4000 rpm for 60 s. The coating was then annealed at 100 °C for 1 min and then at 150 °C for 10 min to obtain a perovskite film with a thickness of approximately 600 nm. S4. Preparation of the electron transport layer: C60 is deposited on the perovskite light-absorbing layer obtained in step S3 by thermal evaporation. The prepared flexible substrate is then placed in the magnetron sputtering cavity, and the vacuum level is evacuated to 1.0 × 10⁻⁶. -5 Evaporation was started at Pa, the evaporation rate was controlled at 0.125 nm / s, and the evaporation time was 8 min, resulting in a C60 thin film with a thickness of 30 nm as an electron transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the electron transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (< 1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0029] Comparative Example 4 In this comparative example 4, the preparation was as follows: Figure 2 The high-efficiency flexible perovskite solar cell with an inverted structure shown comprises a flexible substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer (metal oxide electron transport layer), and a metal back electrode, which are stacked sequentially. The specific fabrication method is shown below: S1. Selection and treatment of flexible substrate: Polyethylene terephthalate (PET) with a thickness of 100μm was selected as the flexible substrate. In a clean environment, the PET substrate was surface treated with a UV ozone cleaner to improve its hydrophilicity and adhesion. S2. Preparation of the hole transport layer: A NiO thin film was prepared as the hole transport layer using magnetron sputtering. The flexible substrate prepared in step S1 was placed in the magnetron sputtering cavity, and the vacuum level was evacuated to 1.0 × 10⁻⁶. -6 Sputtering deposition began at Pa, with the following conditions: temperature: 150℃, power: 100W, cavity pressure: 0.9Pa, oxygen-argon ratio: O2:Ar=9:1, and sputtering time: 5min. Finally, a NiO film with a thickness of 30nm was obtained, which served as the hole transport layer for the perovskite solar cell. S3. Preparation of the perovskite light-absorbing layer: 1449 mg PbI2 was dissolved in 2 ml of DMF:DMSO = 4:1 solution and heated to 50 °C with stirring for 2 h to obtain a PbI2 solution. Then, 181 mg CH3NH3I and 20 mg MACl were added to 2 ml of isopropanol (IPA) and stirred for 2 h to obtain a FAI solution. During preparation: 60 µL of PbI2 solution was spin-coated on the surface of the hole transport layer obtained in step S2 under nitrogen atmosphere with a spin-coating parameter of 1500 r for 30 s. Then, 90 µL of FAI solution was spin-coated in air atmosphere with a spin-coating parameter of 2000 r for 30 s. Finally, the layer was annealed at 150 °C for 15 min to obtain a perovskite film with a thickness of approximately 600 nm. S4. Preparation of electron transport layer: C60 is deposited on the perovskite light-absorbing layer obtained in step S3 by thermal evaporation. The above-treated flexible substrate is placed in the magnetron sputtering cavity, and the vacuum degree is evaporated to 1.0×10-5 Pa to start the evaporation. The evaporation rate is controlled at 0.125nm / s, and the evaporation time is 8min. A C60 thin film with a thickness of 30nm is obtained as the electron transport layer. S5. Deposition of the metal back electrode: A layer of silver (Ag) is deposited on the electron transport layer obtained in step S4 as the metal back electrode using a thermal evaporation method. The evaporation rate is controlled at 0.1 nm / s until the required thickness (100 nm ± 5 nm) is reached. Throughout the evaporation process, a high vacuum environment (< 1 × 10⁻⁶) is maintained. -6 Torr) to ensure the purity and uniformity of the metal layer.

[0030] Figure 3 These are SEM images of the perovskite light-absorbing layer surfaces of Comparative Example 1(a) and Example 1(b) of the present invention. The results show that the crystallinity of the perovskite film is greatly improved after specific laser treatment, which is consistent with the improvement in current and voltage of the perovskite solar cell after subsequent laser treatment.

[0031] Figure 4 These are comparative examples 1(a) and 1(b) of the present invention, showing the state of the flexible substrate after conventional heating and laser annealing. The results show that, upon comparison, the flexible substrate in (a) softens and shrinks during conventional annealing, which is not conducive to the subsequent fabrication of perovskite solar cells. In contrast, the flexible substrate in (b) after laser annealing can maintain its flatness, ensuring the effectiveness of subsequent cell fabrication.

[0032] Figure 5These are voltage and current density performance graphs of the high-efficiency flexible perovskite solar cells of Comparative Examples 1-4 and Examples 1-4 of the present invention. The results show that Figure (a) illustrates that the one-step formal flexible perovskite solar cell after laser annealing has better performance than conventional annealing; Figure (b) illustrates that the two-step formal flexible perovskite solar cell after laser annealing has better performance than conventional annealing; Figure (c) illustrates that the one-step inverted flexible perovskite solar cell after laser annealing has better performance than conventional annealing; and Figure (d) illustrates that the two-step inverted flexible perovskite solar cell after laser annealing has better performance than conventional annealing. Figure 6 The figures are PCE box plots of the high-efficiency flexible perovskite solar cells of Comparative Examples 1-4 and Examples 1-4 of the present invention. The results show that, after comprehensively comparing the various comparative examples and examples, the one-step flexible perovskite solar cell after laser annealing has better performance.

[0033] Figure 7 The figures show the MPPT efficiency stability of the high-efficiency flexible perovskite solar cells of Comparative Example 1 and Example 4 of the present invention. The results show that by comparing Comparative Example 1 and Example 1, it can be more clearly seen that the one-step flexible perovskite solar cell after laser annealing has better MPPT stability.

[0034] Figure 8 The diagram shows the mechanical efficiency stability of the high-efficiency flexible perovskite solar cells of Comparative Example 1 and Example 1 of the present invention. The results show that by comparing Comparative Example 1 and Example 1, it can be more clearly seen that the one-step flexible perovskite solar cell after laser annealing has better mechanical stability.

[0035] In summary, laser annealing is a method that uses a high-energy laser beam to irradiate perovskite thin films to achieve rapid crystallization. This method can not only complete the annealing process in a short time, but also precisely control the temperature gradient and heating rate, thereby optimizing the crystallization quality of the perovskite. Compared with traditional hot-stage annealing, laser annealing can avoid the damage to the material caused by prolonged high-temperature treatment, while improving production efficiency. Furthermore, laser annealing can achieve efficient crystallization at lower temperatures, which is crucial for maintaining the integrity and stability of flexible substrates. In addition, laser annealing can also form uniform perovskite films on flexible substrates, thereby improving battery performance and lifespan. It is worth mentioning that laser annealing technology also has high flexibility and controllability. By adjusting parameters such as laser wavelength, power, and scanning speed, the crystallization process of perovskite thin films can be precisely controlled, thereby meeting the battery preparation requirements with different performance requirements. This high degree of customizability makes laser annealing technology have broad application prospects in the production of flexible perovskite batteries. The laser-annealed flexible perovskite solar cell fabrication method has brought revolutionary breakthroughs to the new energy field with its high efficiency, precision and flexibility. With the continuous progress and improvement of the technology, flexible perovskite solar cells will show their huge application potential and commercial value in more fields in the future.

[0036] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A high-efficiency flexible perovskite solar cell based on laser annealing technology, characterized in that: The high-efficiency flexible perovskite solar cell includes a flexible substrate, a metal oxide electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal back electrode. The perovskite light-absorbing layer is formed by spin-coating a perovskite precursor solution to form a pretreated perovskite film, and then crystallizing the pretreated perovskite film using laser annealing technology.

2. The high-efficiency flexible perovskite solar cell based on laser annealing technology according to claim 1, characterized in that: The high-efficiency flexible perovskite solar cell includes a formal structure or an inverse structure. The high-efficiency flexible perovskite solar cell with the formal structure includes a flexible substrate, a metal oxide electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal back electrode stacked sequentially. The high-efficiency flexible perovskite solar cell with an inverted structure comprises a flexible substrate, a hole transport layer, a perovskite light-absorbing layer, a metal oxide electron transport layer, and a metal back electrode, which are stacked sequentially.

3. The high-efficiency flexible perovskite solar cell based on laser annealing technology according to claim 1, characterized in that: The flexible substrate includes polyethylene terephthalate or polyimide.

4. The high-efficiency flexible perovskite solar cell based on laser annealing technology according to claim 1, characterized in that: The perovskite precursor solution was prepared by dissolving PbI2, CsI, CH3NH3I, and MACl in DMF and DMSO solutions to obtain (CH3NH3). 0.9 Cs 0.1 PbI3; Alternatively, PbI2 can be dissolved in DMF and DMSO solutions to prepare a PbI2 solution; CH3NH3I and MACl can be dissolved in isopropanol to prepare a FAI solution. When using PbI2 solution and FAI solution to prepare perovskite films, the PbI2 solution is spin-coated first, followed by the FAI solution.

5. A high-efficiency flexible perovskite solar cell based on laser annealing technology according to claim 1, characterized in that: The laser annealing technology involves using a high-energy laser beam to irradiate the pretreated perovskite film to complete the crystallization process. The laser wavelength is 400-800 nm, and the power density is 0.1-10 W / cm². 2 The scanning speed is 10-100 mm / s, and the temperature is 25-150℃.

6. A method for fabricating a high-efficiency flexible perovskite solar cell based on laser annealing technology as described in any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Provide a flexible substrate and form a metal oxide electron transport layer or hole transport layer on the flexible substrate; Step 2: Spin-coat a perovskite precursor solution onto a metal oxide electron transport layer or hole transport layer to form a pretreated perovskite film. Then, use laser annealing technology to crystallize the pretreated perovskite film to form a perovskite light absorption layer. Step 3: Form a metal oxide electron transport layer or hole transport layer on the perovskite light absorption layer; Step 4: Deposit a metal back electrode on the metal oxide electron transport layer or hole transport layer, and then encapsulate it to obtain a flexible perovskite solar cell.

7. The method for fabricating a high-efficiency flexible perovskite solar cell based on laser annealing technology according to claim 6, characterized in that: In steps one and three, SnO2 is spin-coated or grown in a water bath on a flexible substrate or perovskite light-absorbing layer, or C60 is thermally evaporated to form a metal oxide electron transport layer. Spiro-OMeTAD solution is spin-coated or NiO is spin-coated on a flexible substrate or perovskite light-absorbing layer to form a hole transport layer.

8. The method for fabricating a high-efficiency flexible perovskite solar cell based on laser annealing technology according to claim 6, characterized in that: In step three, a layer of silver is deposited on the metal oxide electron transport layer or hole transport layer as a metal back electrode by thermal evaporation.

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