Method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate

Abstract

The application discloses a kind of thiosulfate doped low stress room temperature flexible perovskite film deposition method, it is related to perovskite solar cell field, the method includes: preparation perovskite precursor solution;Iodine is added as additive to perovskite precursor solution to obtain mixed solution;Mixed solution is prepared into thin film by spin coating process, anti-solvent is added dropwise to the surface of thin film in the spin coating process, and perovskite thin film is formed after normal temperature standing;Wherein, anti-solvent is chlorobenzene solution doped with thiosulfate.The application realizes controllable heat release by the redox reaction of thiosulfate and iodine, replaces traditional heat annealing process, can promote precursor solvent volatilization, induces perovskite material crystallization, and high-quality perovskite thin film can be obtained at room temperature.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, specifically relating to a method for deposition of low-stress, room-temperature flexible perovskite thin films doped with thiosulfate. Background Technology

[0002] In recent years, organic-inorganic perovskite materials have attracted widespread attention due to their excellent optical properties (such as high light absorption coefficient, low exciton binding energy, and micron-scale carrier diffusion length), and are considered one of the strong contenders for next-generation photovoltaic materials. Meanwhile, the rapid emergence of new application scenarios such as polar scientific expeditions, smart wearable devices, building-integrated photovoltaics (BIPV), and vehicle-mounted photovoltaic systems (VIPV) has greatly expanded the market size of flexible solar cells, driving the development of solar cell technology towards flexibility and lightweight design. In particular, as a "soft crystal" material, perovskite materials have a low crystallization temperature (≤150℃) and a bulk modulus to shear modulus ratio exceeding 2.0, enabling them to withstand significant compression, deformation, and bending, demonstrating considerable potential for flexible solar cell fabrication. The photoelectric conversion efficiency of flexible perovskite solar cells (F-PSCs) fabricated from perovskite has already exceeded 25%. However, this efficiency still lags behind that of rigid perovskite solar cells, indicating significant room for improvement.

[0003] One of the key factors limiting the performance of flexible perovskite solar cells is that traditional perovskite thin film deposition technology heavily relies on thermal annealing (typically >100°C for more than 10 minutes). This process can lead to the volatilization of organic cations in the perovskite lattice, causing lattice distortion and residual stress, thus affecting the crystal quality and photoelectric performance of the film. It also increases fabrication costs and process complexity. Furthermore, flexible substrates (such as polymer materials like PET, PEN, and PI) have relatively low glass transition temperatures (around 70°C) and high coefficients of thermal expansion, making them prone to deformation during high-temperature annealing. This can lead to delamination between the perovskite film and the substrate interface and internal stress accumulation, further reducing device reliability. Therefore, developing room-temperature perovskite thin film fabrication processes is of great significance. It is crucial for avoiding flexible substrate deformation, lattice defects, and interface problems caused by high-temperature annealing, reducing the production cost of flexible perovskite solar cells, simplifying the process flow, and accelerating the commercialization of flexible perovskite solar cells.

[0004] To date, stress modulation technology for room-temperature flexible perovskite thin films is still in its early stages of development. Mainstream methods include vacuum room-temperature deposition, low-boiling-point solvent annealing, and compositional modulation and additive-assisted crystallization. These methods generally aim to alleviate thermal stress caused by coefficient of thermal expansion (CTE) mismatch and have achieved initial success in reducing internal stress, improving crystallization quality, and enhancing device stability. However, this field still faces several key challenges: while vacuum room-temperature deposition can achieve low-stress deposition, the complexity and cost of the equipment limit its large-scale application; while low-boiling-point solvent annealing (such as ether solvent annealing) can effectively release stress, crystallization control is difficult, resulting in generally poor film quality and low device efficiency; and while compositional modulation and additive-assisted crystallization can synergistically optimize crystallization and stress states and significantly improve device stability and performance, their efficiency is still generally lower than that of traditional thermally annealed devices. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a method for depositing low-stress, room-temperature flexible perovskite thin films doped with thiosulfate. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a method for depositing low-stress, room-temperature flexible perovskite thin films doped with thiosulfate, comprising:

[0007] Step 1: Prepare perovskite precursor solution;

[0008] Step 2: Iodine is added as an additive to the perovskite precursor solution to obtain a mixed solution;

[0009] Step 3: The mixed solution is prepared into a thin film by spin coating. During the spin coating process, an anti-solvent is dropped onto the surface of the thin film, and after standing at room temperature, a perovskite thin film is formed.

[0010] The antisolvent is a chlorobenzene solution doped with thiosulfate.

[0011] This invention provides a perovskite thin film, which is prepared by the low-stress room temperature flexible perovskite thin film deposition method with thiosulfate doping as described in any of the embodiments.

[0012] This invention provides a flexible perovskite solar cell, which includes a PET flexible substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer stacked from bottom to top; wherein the perovskite layer is prepared by the low-stress room temperature flexible perovskite thin film deposition method with thiosulfate doping as described in any embodiment.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. The thiosulfate-doped low-stress room-temperature flexible perovskite thin film deposition method of the present invention innovatively introduces iodine as an additive in the perovskite precursor solution preparation stage, and adds a chlorobenzene solution doped with thiosulfate to the film for film extraction in the spin coating stage. The controllable exothermic reaction between thiosulfate and iodine is achieved through redox reaction, which replaces the traditional thermal annealing process. This can promote the evaporation of precursor solvent, induce the crystallization of perovskite material, and obtain high-quality perovskite thin films at room temperature.

[0015] 2. In this invention, since iodine and thiosulfate are uniformly distributed in the precursor solution and inside the film, the exothermic reaction can proceed uniformly in the film, ensuring uniform heating during the crystallization process. This characteristic has a significant advantage in large-area uniform film formation.

[0016] 3. In this invention, the tetrathionate, a redox byproduct of thiosulfate and iodine, can react with Pb. 2+ Formation of soluble complexes (e.g., [Pb(S2O3)2]) 2- This effectively reduces the activation energy of perovskite crystallization, further reducing the difficulty of room-temperature perovskite film deposition; the active iodine and free cations generated by the reaction can fill the halogen vacancy defects in the perovskite film, optimize the carrier transport dynamics, and thus significantly improve the photoelectric performance of room-temperature flexible perovskite films.

[0017] 4. In this invention, the modulation of thiosulfate cations (such as NH4) is achieved. + The activation energy and crystallization kinetics of perovskite films can be further modulated by ions, thereby improving the photoelectric properties of room temperature perovskite films. By modulating the crystallization kinetics of perovskite films and passivating cation vacancy defects, the quality of room temperature perovskite films can be further optimized.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for depositing low-stress, room-temperature flexible perovskite thin films doped with thiosulfate, provided in an embodiment of the present invention.

[0020] Figure 2 These are process comparison diagrams of the conventional thin film deposition method and the perovskite thin film deposition method of the present invention, wherein (a) is the conventional thin film deposition method and (b) is the perovskite thin film deposition method of the present invention.

[0021] Figure 3These are scanning electron microscope images of the titanium dioxide thin films of Example 1 and Comparative Example 1;

[0022] Figure 4 These are the X-ray diffraction patterns of the titanium dioxide thin films of Example 1 and Comparative Example 1;

[0023] Figure 5 This is a schematic diagram of a flexible perovskite solar cell provided in an embodiment of the present invention;

[0024] Figure 6 This is a JV curve of a flexible perovskite solar cell fabricated based on the perovskite thin film of Example 1 and Comparative Example 1. Detailed Implementation

[0025] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following describes in detail a method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to the present invention, in conjunction with the accompanying drawings and specific embodiments.

[0026] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0027] In a first aspect, embodiments of the present invention provide a method for depositing low-stress, room-temperature flexible perovskite thin films doped with thiosulfate. Please refer to [link to relevant documentation]. Figure 1 , Figure 1 This is a flowchart of a method for depositing low-stress, room-temperature flexible perovskite thin films doped with thiosulfate, as provided in an embodiment of the present invention. Figure 1 As shown, the method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to an embodiment of the present invention includes the following steps:

[0028] Step 1: Prepare perovskite precursor solution.

[0029] In an optional embodiment, step 1 includes: dissolving the metal halide and the organic amine salt in a mixed solvent to obtain a perovskite precursor solution.

[0030] Optionally, the mixed solvent is a mixture of 2-methoxyethanol (2-Me) and tetrahydrofuran (THF), with a volume ratio of 2-Me to THF of 7:3 to 1:1, for example, but not limited to 7:3, 6:4 or 1:1.

[0031] In this embodiment, the THF solvent evaporation temperature is 66°C, which is one of the key factors to ensure low-temperature perovskite film deposition.

[0032] Optionally, the metal halide includes at least one of lead iodide, lead bromide, cesium lead chloride iodide, cesium bromide, and cesium chloride.

[0033] Optionally, the organic amine salt includes at least one of iodomethylamine, bromomethylamine, chloromethylamine, iodomethylammonium, bromomethylammonium, and chloromethylammonium.

[0034] It is understandable that the perovskite precursor solution is formed by dissolving the perovskite material in a solvent. The perovskite material can be: MA x FA 1-x PbI 3-a Br a MA x FA 1-x PbI 3-b Cl b MA x FA 1-x PbBr 3-c Cl c FA 1-y Cs y PbI3, Cs x FA 1- x PbI 3-a Br a or Cs 1-y (FA x MA 1-x ) y In PbI3, x and y both take values ​​from 0 to 1, and a, b, and c both take values ​​from 0 to 3. It is understood that the perovskite material of this invention is not limited to the above-mentioned compound, but can also be other perovskite materials deemed suitable by those skilled in the art.

[0035] Step 2: Iodine is added as an additive to the perovskite precursor solution to obtain a mixed solution.

[0036] Optionally, the concentration of the additive, i.e., iodine, in the mixed solution is 0.05-0.2 mmol / mL, for example, but not limited to 0.05 mmol / mL, 0.1 mmol / mL, 0.15 mmol / mL or 0.2 mmol / mL.

[0037] In an optional embodiment, step 2 includes: adding iodine to the perovskite precursor solution, stirring and mixing it evenly in a constant temperature container, and filtering the mixture using a PTFE hydrophobic membrane to obtain a mixed solution.

[0038] Optionally, the temperature of the constant temperature container is 75°C, the heating step is 1°C, and the stirring time is 12h.

[0039] Optionally, the PTFE hydrophobic filter membrane has a pore size of 0.45 μm.

[0040] Step 3: Prepare a thin film from the mixed solution by spin coating. During spin coating, add anti-solvent to the surface of the film and let it stand at room temperature to form a perovskite film.

[0041] The antisolvent is a chlorobenzene solution doped with thiosulfate.

[0042] Optionally, the thiosulfate includes at least one of sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, calcium thiosulfate, magnesium thiosulfate, silver thiosulfate, zinc thiosulfate, and barium thiosulfate.

[0043] In an optional embodiment, the concentration of thiosulfate in the antisolvent is 0.5-2 mmol / mL, for example, but not limited to 0.5 mmol / mL, 1.0 mmol / mL, 1.5 mmol / mL or 2 mmol / mL.

[0044] In an optional embodiment, step 3 includes:

[0045] The mixed solution is dropped onto the substrate and rotated at 500-1000 rpm / s for 5-10 seconds, then rotated at 3500-5500 rpm / min for 30-55 seconds. 12-20 seconds before the end of spin coating, 150-250 μL of antisolvent is dropped onto the film surface. After standing at room temperature, the perovskite film is obtained.

[0046] Optionally, the settling time should be at least 4 hours.

[0047] The present invention provides a method for deposition of low-stress, room-temperature flexible perovskite thin films doped with thiosulfate. In the perovskite precursor solution preparation stage, iodine is innovatively introduced as an additive. During the spin-coating stage, a chlorobenzene solution doped with thiosulfate is dropped onto the film for extraction. Controllable exothermic reaction between thiosulfate and iodine is achieved through a redox reaction, replacing traditional thermal annealing. This promotes precursor solvent evaporation, induces perovskite material crystallization, and yields high-quality perovskite thin films at room temperature. In this invention, because iodine and thiosulfate are uniformly distributed in the precursor solution and within the film, the exothermic reaction can proceed uniformly within the film, ensuring uniform heating during crystallization. This characteristic offers significant advantages for large-area uniform film deposition.

[0048] In this invention, the tetrathionate, a redox byproduct of thiosulfate and iodine, can react with Pb. 2+ Formation of soluble complexes (e.g., [Pb(S2O3)2]) 2-This effectively reduces the activation energy of perovskite crystallization, further simplifying the deposition of room-temperature perovskite films. The generated active iodine and free cations can fill halogen vacancies in the perovskite film, optimizing carrier transport dynamics and thus significantly improving the photoelectric properties of room-temperature flexible perovskite films. Modulation with thiosulfate cations (such as NH4+) further enhances these properties. + The activation energy and crystallization kinetics of perovskite films can be further modulated by ions, thereby improving the photoelectric properties of room temperature perovskite films. By modulating the crystallization kinetics of perovskite films and passivating cation vacancy defects, the quality of room temperature perovskite films can be further optimized.

[0049] In this invention, sulfur oxides (such as SO4) produced by the decomposition of thiosulfates 2- and [Pb(S2O3)2] 2- It will interact with uncoordinated Pb on the perovskite surface. 2+ This combination reduces the surface energy of the thin film, enhancing its hydrophobicity and long-term stability.

[0050] Furthermore, combined Figure 2 The process diagram shown illustrates the effectiveness of the thiosulfate-doped low-stress room-temperature flexible perovskite thin film deposition method of the present invention through specific embodiments and comparative examples. Figure 2 These are process comparison diagrams of the conventional thin film deposition method and the perovskite thin film deposition method of the present invention, wherein (a) is the conventional thin film deposition method and (b) is the perovskite thin film deposition method of the present invention.

[0051] Example 1

[0052] S1: PbI2, FAI and CsI are dissolved in 1 mL of a 2-Me / THF mixed solvent with a volume ratio of 7:3 to obtain a perovskite precursor solution;

[0053] S2: Iodine was added as an additive to the perovskite precursor solution and stirred in a constant temperature container at 75°C for 12 hours to mix evenly. The mixture was then filtered through a PTFE hydrophobic membrane with a pore size of 0.45 μm to obtain a mixed solution. The concentration of the additive in the mixed solution was 0.05 mmol / mL.

[0054] S3: 75 μL of the mixed solution was dropped onto the substrate and then spin-coated: first, the spin-coating was performed at 800 rpm / s for 5 seconds, then at 5500 rpm / min for 35 seconds. 15 seconds before the end of the spin-coating, 200 μL of sodium thiosulfate-doped chlorobenzene antisolvent was dropped onto the film surface. The concentration of sodium thiosulfate in the antisolvent was 0.5 mmol / mL. After that, the film was allowed to stand at room temperature for 4 hours to obtain a perovskite film.

[0055] Understandably, sodium thiosulfate can also be replaced with potassium thiosulfate, ammonium thiosulfate, calcium thiosulfate, magnesium thiosulfate, silver thiosulfate, zinc thiosulfate, or barium thiosulfate.

[0056] Example 2

[0057] S1: PbI2, FAI and CsI are dissolved in 1 mL of a 2-Me / THF mixed solvent with a volume ratio of 6:4 to obtain a perovskite precursor solution;

[0058] S2: Iodine was added as an additive to the perovskite precursor solution and stirred in a constant temperature container at 75°C for 12 hours to mix evenly. The mixture was then filtered through a PTFE hydrophobic membrane with a pore size of 0.45 μm to obtain a mixed solution. The concentration of the additive in the mixed solution was 0.1 mmol / mL.

[0059] S3: 75 μL of the mixed solution was dropped onto the substrate and then spin-coated: first, the spin was rotated at 800 rpm / s for 5 seconds, then at 5500 rpm / min for 35 seconds. 15 seconds before the end of the spin coating, 200 μL of sodium thiosulfate-doped chlorobenzene antisolvent was dropped onto the film surface. The concentration of sodium thiosulfate in the antisolvent was 1 mmol / mL. After that, the film was left to stand at room temperature for 4 hours to obtain a perovskite film.

[0060] Understandably, sodium thiosulfate can also be replaced with potassium thiosulfate, ammonium thiosulfate, calcium thiosulfate, magnesium thiosulfate, silver thiosulfate, zinc thiosulfate, or barium thiosulfate.

[0061] Example 3

[0062] S1: PbI2, FAI and CsI are dissolved in 1 mL of a 1:1 volume ratio 2-Me / THF mixed solvent to obtain a perovskite precursor solution;

[0063] S2: Iodine was added as an additive to the perovskite precursor solution and stirred in a constant temperature container at 75°C for 12 hours to mix evenly. The mixture was then filtered through a PTFE hydrophobic membrane with a pore size of 0.45 μm to obtain a mixed solution. The concentration of the additive in the mixed solution was 0.2 mmol / mL.

[0064] S3: 75 μL of the mixed solution was dropped onto the substrate and then spin-coated: first, the spin was performed at 800 rpm / s for 5 seconds, then at 5500 rpm / min for 35 seconds. 15 seconds before the end of the spin coating, 200 μL of sodium thiosulfate-doped chlorobenzene antisolvent was dropped onto the film surface. The concentration of sodium thiosulfate in the antisolvent was 2 mmol / mL. After that, the film was left to stand at room temperature for 4 hours to obtain a perovskite film.

[0065] Understandably, sodium thiosulfate can also be replaced with potassium thiosulfate, ammonium thiosulfate, calcium thiosulfate, magnesium thiosulfate, silver thiosulfate, zinc thiosulfate, or barium thiosulfate.

[0066] Comparative Example 1

[0067] S1: PbI2, FAI and CsI are dissolved in 1 mL of a 2-Me / THF mixed solvent with a volume ratio of 7:3 to obtain a perovskite precursor solution;

[0068] S2: A 75 μL perovskite precursor solution was drop-coated onto the substrate, followed by spin-coating: first, the film was spin-coated at 1000 rpm / s for 10 seconds, then at 5000 rpm / min for 30 seconds. Eight seconds before the end of the spin-coating, 200 μL of chlorobenzene was continuously added drop-by drop onto the film surface as an anti-solvent. The film was then rapidly transferred to a hot plate at 100°C for annealing for 30 minutes to obtain the perovskite film.

[0069] Please see Figure 3 , Figure 3 These are scanning electron microscope images of the perovskite films of Example 1 and Comparative Example 1. Clearly, compared to Comparative Example 1, the perovskite film prepared in Example 1 has significantly larger and more uniform grain size, exhibiting better morphological characteristics.

[0070] Please see Figure 4 , Figure 4 These are the X-ray diffraction patterns of the perovskite films of Example 1 and Comparative Example 1. Compared to Comparative Example 1, the perovskite film prepared in Example 1 has stronger (100) crystal plane derivation peaks, indicating higher film crystallinity.

[0071] Secondly, embodiments of the present invention provide a perovskite thin film, which is prepared using the low-stress room-temperature flexible perovskite thin film deposition method with thiosulfate doping provided in the first aspect.

[0072] For details regarding the perovskite film and its beneficial effects, please refer to the relevant content on the low-stress room-temperature flexible perovskite film deposition method doped with thiosulfate provided in the first aspect, which will not be repeated here.

[0073] Thirdly, embodiments of the present invention provide a flexible perovskite solar cell, please refer to [link to relevant documentation]. Figure 5 , Figure 5 This is a schematic diagram of a flexible perovskite solar cell provided in an embodiment of the present invention, as shown below. Figure 5As shown, the flexible perovskite solar cell includes a PET flexible substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer stacked from bottom to top; wherein, the perovskite layer is prepared by the low-stress room temperature flexible perovskite thin film deposition method with thiosulfate doping provided in the first aspect.

[0074] Taking sodium thiosulfate as an example, the preparation structure is PET / NiO. X / Me-4PACz / / Cs 0.06 FA 0.94 PbI3 / PC 61 The process of BM / Ag perovskite solar cell devices is as follows:

[0075] (1) Processing method for PET flexible substrate:

[0076] First, use a lint-free cloth soaked in isopropanol to wipe the etched PET flexible substrate (10 ohms / square, 100 nanometers) to remove surface dust particles, then use a nitrogen gun to blow it clean. Subsequently, the flexible substrate is cleaned in an ultrasonic cleaning tank in sequence with deionized water, acetone and isopropanol and stored in an alcohol solution.

[0077] (2) Method for preparing the hole transport layer:

[0078] The substrate was removed, dried with nitrogen, and then dried at 120°C for 20 minutes. It was then treated with ultraviolet ozone for 30 minutes to remove organic contaminants and increase its surface hydrophilicity. Subsequently, 100 μL of a mixture of Me-4PACz and anhydrous ethanol (0.335 mg / mL) was spin-coated at 3000 rpm / min for 30 seconds, dried at 100°C for 10 minutes, and then treated with ultraviolet ozone again for 30 minutes before being stored for later use.

[0079] (3) Preparation method of perovskite precursor solution:

[0080] The preparation method of the perovskite precursor solution includes: dissolving 691.50 mg of PbI2, 227.00 mg of FAI and 21.04 mg of CsI in 1 mL of a 2-Me / THF mixed solvent with a volume ratio of 7:3, and adding iodine at a concentration of 0.05 mmol / mL as an additive. The mixture is stirred in a constant temperature container at 75 °C for 12 h to achieve uniform mixing. The solution is then filtered through a PTFE hydrophobic membrane with a pore size of 0.45 μm to obtain the perovskite precursor solution with added iodine.

[0081] (4) Methods for preparing perovskite thin films:

[0082] A 75 μL solution of iodine-added perovskite precursor was applied to the surface of a flexible substrate covered by a hole transport layer, followed by spin coating: first, spin coating at 800 rpm / s for 5 seconds, then at 5500 rpm / min for 35 seconds. Fifteen seconds before the end of spin coating, 200 μL of chlorobenzene / sodium thiosulfate was continuously added dropwise to the film surface as an antisolvent. The film was then allowed to stand at room temperature for 4 hours.

[0083] (5) Preparation method of electron transport layer and silver electrode:

[0084] After the room temperature perovskite thin film deposition was completed, the treated film was neatly arranged on a custom mask, and a 20 nm thick PC layer was deposited under vacuum at a rate of 0.5 Å / s. 61 The electron transport layer is followed by a 100 nm thick silver electrode deposited at 0.5 Å / s.

[0085] Please see Figure 6 , Figure 6 This is a JV curve diagram of the flexible perovskite solar cells fabricated based on the perovskite thin films of Example 1 and Comparative Example 1. Clearly, compared to Comparative Example 1, the perovskite solar cell prepared in Example 1 has a higher photoelectric conversion efficiency, especially with a significant improvement in short-circuit current and fill factor.

[0086] This invention utilizes thiosulfate as a key raw material, significantly reducing the material cost of room-temperature flexible perovskite thin film deposition. In-situ exothermic reactions are achieved through redox reactions, completely eliminating the need for traditional high-temperature annealing processes and reducing energy consumption by over 80%. Simultaneously, reaction byproducts automatically passivate film defects, simplifying post-processing steps. Under conditions compatible with continuous production processes, the production efficiency of corresponding flexible perovskite solar cells is expected to increase by more than three times, with overall production costs reduced by over 60%, indicating a broad application market.

[0087] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0088] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0089] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for depositing low-stress, room-temperature flexible perovskite thin films doped with thiosulfate, characterized in that, include: Step 1: Prepare perovskite precursor solution; Step 2: Iodine is added as an additive to the perovskite precursor solution to obtain a mixed solution; Step 3: The mixed solution is prepared into a thin film by spin coating. During the spin coating process, an anti-solvent is dropped onto the surface of the thin film, and after standing at room temperature, a perovskite thin film is formed. The antisolvent is a chlorobenzene solution doped with thiosulfate.

2. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 1, characterized in that, Step 1 includes: The perovskite precursor solution is obtained by dissolving a metal halide and an organic amine salt in a mixed solvent; wherein the mixed solvent is a mixture of 2-methoxyethanol and tetrahydrofuran in a volume ratio of 7:3 to 1:

1.

3. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 2, characterized in that, The metal halide includes at least one of lead iodide, lead bromide, lead chloride, cesium iodide, cesium bromide, and cesium chloride.

4. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 2, characterized in that, The organic amine salt includes at least one of iodomethylamine, bromomethylamine, chloromethylamine, iodomethylammonium, bromomethylammonium, and chloromethylammonium.

5. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 1, characterized in that, The concentration of the additive in the mixed solution is 0.05-0.2 mmol / mL.

6. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 1, characterized in that, The thiosulfate includes at least one of sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, calcium thiosulfate, magnesium thiosulfate, silver thiosulfate, zinc thiosulfate, and barium thiosulfate.

7. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 1, characterized in that, The concentration of thiosulfate in the antisolvent is 0.5-2 mmol / mL.

8. The method for deposition of low-stress room-temperature flexible perovskite thin films doped with thiosulfate according to claim 1, characterized in that, Step 3 includes: The mixed solution is dropped onto the substrate and rotated at a speed of 500-1000 rpm / s for 5-10 seconds, then rotated at a speed of 3500-5500 rpm / min for 30-55 seconds. 12-20 seconds before the end of spin coating, 150-250 μL of antisolvent is dropped onto the film surface. After standing at room temperature, the perovskite film is obtained.

9. A perovskite thin film, characterized in that, It was prepared by the low-stress room-temperature flexible perovskite thin film deposition method with thiosulfate doping as described in any one of claims 1-8.

10. A flexible perovskite solar cell, characterized in that, The flexible perovskite solar cell comprises, from bottom to top, a PET flexible substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer; wherein, the perovskite layer is prepared by the low-stress room-temperature flexible perovskite thin film deposition method doped with thiosulfate as described in any one of claims 1-8.

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