Flexible perovskite thin film, cell and preparation method

Abstract

The invention relates to a flexible perovskite thin film, a cell and a preparation method, and the method comprises the following steps: preparing a perovskite precursor solution which contains an anionic surfactant used for reducing the contact angle of the solution on a flexible hydrophobic substrate, and the addition amount of the anionic surfactant is 0.05-0.3% of the total mass of the solution; coating the perovskite precursor solution on a flexible conductive substrate to form a wet film; the wet film is immediately subjected to vacuum flash evaporation treatment after coating, and the process conditions of the vacuum flash evaporation treatment are as follows: the environment pressure is reduced to below 8-12 Pa from normal pressure within 8-12 seconds, and the environment pressure is maintained for 10-30 seconds; and carrying out annealing treatment on the thin film after vacuum flash evaporation to form the flexible perovskite thin film. According to the invention, the problem that the coating wettability of the perovskite solution on the flexible conductive substrate is poor is effectively solved, and meanwhile, the complete perovskite thin film can be prepared on the flexible conductive substrate with a larger area.

Description

Technical Field

[0001] This invention relates to the field of perovskite battery technology, and in particular to a flexible perovskite thin film, a battery, and a method for its preparation. Background Technology

[0002] Reducing carbon emissions is a key strategy for addressing the escalating global climate change, and the development and application of renewable energy by various countries has created a favorable environment for the development of solar energy technology. Solar energy, due to its wide distribution and inexhaustible resources, can play a vital role in achieving the goal of reducing carbon emissions. In particular, perovskite solar cells, with their advantages of low cost, high efficiency, and tunable bandgap, are considered one of the most promising photovoltaic technologies. Furthermore, compared to crystalline silicon solar cells, perovskite solar cells can be fabricated on flexible substrates, adapting to surfaces of various complex shapes, thus showing broad application prospects in wearable devices, building-integrated photovoltaics (BIPV), distributed power generation, and portable device charging.

[0003] Currently, the reported energy conversion efficiency of small-area flexible perovskite solar cells has exceeded 26%, very close to that of rigid cells. In terms of fabrication processes, flexible perovskite solar cells typically employ low-temperature fabrication, which helps reduce production costs and imposes less stringent equipment requirements compared to high-temperature processes. Flexible perovskite solar cells, with their flexibility and portability, are more adaptable to various application scenarios. Furthermore, in complex outdoor environmental tests such as hail tests, their impact resistance allows them to pass tests more effectively, indicating a broad market and promising future for commercial applications. However, flexible conductive substrates are typically made of polyester materials, which have a certain degree of hydrophobicity. This usually results in poor wetting of the perovskite solution on the substrate, leading to lower energy conversion efficiency in flexible perovskite solar cells.

[0004] In view of the above-mentioned shortcomings, the designer has actively researched and innovated in order to create a flexible perovskite thin film, battery and preparation method, which will make it more industrially valuable. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a flexible perovskite thin film, a battery, and a method for its preparation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] One of the objectives of this invention is:

[0008] A method for preparing a flexible perovskite thin film includes the following steps:

[0009] Step 1: Prepare a perovskite precursor solution containing an anionic surfactant to reduce the contact angle of the solution on a flexible hydrophobic substrate. The amount of anionic surfactant added is 0.05% to 0.3% of the total mass of the solution.

[0010] Step 2: Coat the perovskite precursor solution onto a flexible conductive substrate to form a wet film;

[0011] Step 3: Immediately after coating, the wet film is subjected to vacuum flash evaporation. The process conditions for vacuum flash evaporation are: reducing the ambient pressure from atmospheric pressure to below 8-12 Pa within 8-12 seconds and maintaining this pressure for 10-30 seconds.

[0012] Step 4: Anneal the film after vacuum flash evaporation to form a flexible perovskite film.

[0013] As a further improvement of the present invention, the anionic surfactant is one or more combinations of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium dodecyl phosphate, sodium α-olefin sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl ether sulfate, sodium lauryl sulfate, and fatty alcohol phosphate salts.

[0014] As a further improvement of the present invention, the anionic surfactant is sodium dodecyl phosphate.

[0015] The second objective of this invention is:

[0016] A method for preparing a flexible perovskite solar cell includes the following steps:

[0017] Step 1: Laser scribing P1 is performed on the flexible conductive substrate, followed by cleaning and ultraviolet ozone surface treatment;

[0018] Step 2: Prepare a NiOx hole transport layer on a flexible conductive substrate by vacuum sputtering;

[0019] Step 3: Coat a self-assembled MeO-2PACz monolayer on the NiOx hole transport layer to form a composite hole transport structure;

[0020] Step 4: Prepare a perovskite precursor solution containing an anionic surfactant, wherein the anionic surfactant is sodium dodecyl phosphate, and the amount added is 0.05% to 0.3% of the total mass of the perovskite precursor solution.

[0021] Step 5: The perovskite precursor solution prepared in Step 4 is coated onto the composite hole transport structure by a blade coating method to form a perovskite wet film.

[0022] Step 6: Vacuum flash evaporation is performed on the perovskite wet film, followed by annealing to form a perovskite light-absorbing layer;

[0023] Step 7: Coat the perovskite light-absorbing layer with PEAI passivation layer solution and perform annealing treatment to form a passivation layer;

[0024] Step 8: Vacuum evaporation of C onto the passivation layer 60 Electron transport layer;

[0025] Step 9: In C 60 SnO2 hole-blocking layer is prepared on electron transport layer by atomic layer deposition;

[0026] Step 10: Sequentially prepare an ITO transparent electrode and a Cu metal electrode on the SnO2 hole blocking layer.

[0027] As a further improvement of the present invention, in step 2, the vacuum sputtering process conditions include: sputtering power of 0.8 to 1.2 kW, NiOx thickness of 10 to 15 nm, and process temperature of 80 to 120 °C; in step 3, the coating speed of the MeO-2PACz self-assembled monolayer is 8 to 12 mm / s, the amount is 30 to 35 μL, and the annealing conditions are annealing at 80 to 120 °C for 8 to 12 minutes.

[0028] As a further improvement of the present invention, in step 4, the perovskite precursor solution is prepared by dissolving sodium dodecyl phosphate, lead iodide, formamidinium iodide and cesium iodide in a mixed solvent of DMF and NMP, wherein the volume ratio of DMF to NMP is 9:1, and the amount of sodium dodecyl phosphate added is 0.1% of the total mass of the solution.

[0029] As a further improvement of the present invention, in step 5, the process parameters for the coating include: the coating blade height is 140-160 μm, and the coating speed is 8-12 mm / s; in step 6, the process conditions for the vacuum flash treatment are: reducing the pressure from atmospheric pressure to below 8-12 Pa within 8-12 seconds and maintaining it for 10-30 seconds, and annealing at 100°C for 18-22 minutes.

[0030] As a further improvement of the present invention, in step 7, the concentration of the PEAI passivation layer solution is 0.4–0.6 mg / mL, the solvent is isopropanol, the coating speed is 18–22 mm / s, and the annealing conditions are annealing at 80–120°C for 4–6 minutes; in step 8, C is vacuum evaporated. 60 The process conditions include: a vacuum degree of 6×10 -4 Pa, evaporation rate is The film thickness is 18–22 nm; in step 9, the atomic layer deposition process conditions include: the chamber temperature is stable at 60–100 °C, the tin source is TDMASn, the oxygen source is pure water, the outlet temperature is 60–70 °C, and the number of purging cycles is 70–90.

[0031] As a further improvement of the present invention, in step 10, the fabrication process of the ITO transparent electrode includes: sputtering power of 0.8 to 1.2 kW, oxygen content of 8 to 12% in the argon-oxygen mixture, and ITO thickness of 18 to 22 nm; the fabrication process of the Cu metal electrode includes: sputtering power of 6 to 8 kW, and Cu thickness of 60 to 100 nm.

[0032] The third objective of this invention:

[0033] A flexible perovskite solar cell is prepared by any of the above-described preparation methods.

[0034] By means of the above-described solution, the present invention has at least the following advantages:

[0035] This invention effectively solves the problem of poor wettability of perovskite solution coating on flexible conductive substrates, and at the same time, it can also prepare complete perovskite films on flexible conductive substrates with larger areas.

[0036] The large-area flexible perovskite solar module with a metal back electrode prepared by this invention can achieve an energy conversion efficiency of over 16%.

[0037] 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, the following are preferred embodiments of the present invention described in detail with reference to the accompanying drawings. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a flexible perovskite solar cell according to the second embodiment of the present invention;

[0040] Figure 2 These are images of perovskite films prepared in the control group in the third embodiment of the present invention;

[0041] Figure 3 These are images of the perovskite thin films prepared by the experimental group in the third embodiment of the present invention;

[0042] Figure 4 These are the JV curves of the large-area flexible perovskite solar cells prepared by the experimental and control groups of this invention. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0045] First embodiment of the present invention:

[0046] This embodiment describes a method for preparing a flexible perovskite thin film, comprising the following steps:

[0047] Step 1: Prepare a perovskite precursor solution containing an anionic surfactant to reduce the contact angle of the solution on a flexible hydrophobic substrate. The amount of anionic surfactant added is 0.05% to 0.3% of the total mass of the solution.

[0048] Step 2: Coat the perovskite precursor solution onto a flexible conductive substrate to form a wet film;

[0049] Step 3: Immediately after coating, the wet film is subjected to vacuum flash evaporation. The process conditions for vacuum flash evaporation are: reducing the ambient pressure from atmospheric pressure to below 8-12 Pa within 8-12 seconds and maintaining this pressure for 10-30 seconds.

[0050] Step 4: Anneal the film after vacuum flash evaporation to form a flexible perovskite film.

[0051] The anionic surfactant is one or more of the following: sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium dodecyl phosphate, sodium α-olefin sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl ether sulfate, sodium lauryl sulfate, and fatty alcohol phosphate salts.

[0052] The anionic surfactant is sodium dodecyl phosphate.

[0053] By adding anionic surfactants such as sodium dodecyl phosphate to the perovskite precursor solution, the surface tension of the solution on hydrophobic flexible substrates (such as PET and PEN) was significantly reduced. The contact angle of the perovskite solution on the flexible substrate was greatly reduced, and the wettability was fundamentally improved, enabling the solution to spread uniformly. This lays the material foundation for the preparation of large-area, pore-free, and high-coverage perovskite thin films.

[0054] The phosphate group of sodium dodecyl phosphate can react with perovskite precursors (especially Pb). 2+ This interaction regulates the crystallization process of perovskite. This interaction slows down the crystallization rate and promotes the formation of more uniform crystal nuclei, resulting in high-quality films with more uniform grain size and fewer grain boundaries. Simultaneously, this molecule preferentially occupies grain boundary sites, passivating interface defects to some extent.

[0055] The second embodiment of the present invention:

[0056] like Figure 1 The present embodiment describes the structure of a flexible perovskite solar cell, wherein the structure includes a flexible conductive substrate, a hole transport layer, a perovskite light-absorbing layer, a passivation layer, an electron transport layer, and a back electrode layer.

[0057] The flexible conductive substrate may be one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyimide (PI), and polycarbonate (PC).

[0058] The hole transport layer material is any one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), nickel oxide (NiOx), Spiro-TTB, PEDOT-PSS, or self-contained monolayers (SAMs).

[0059] Furthermore, the hole transport layer can be prepared by any of the following methods: spin coating, blade coating, slot coating, inkjet printing, magnetron sputtering, or vacuum evaporation.

[0060] The method for preparing the perovskite light-absorbing layer film involves adding anionic surfactants to the perovskite precursor solution to change the surface tension of the perovskite solution on a flexible conductive substrate, thereby improving wettability.

[0061] Furthermore, the anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium dodecyl phosphate, sodium α-olefin sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl ether sulfate, sodium lauryl sulfate, and fatty alcohol phosphate salts. This invention selects sodium dodecyl phosphate as a specific example for illustration.

[0062] Furthermore, the perovskite light-absorbing layer can be prepared by any of the following methods: spin coating, blade coating, slot coating, inkjet printing, or vacuum evaporation.

[0063] The passivation layer material is any one or more of the following: phenylethyl ammonium iodide, piperazine monoiodide, piperazine iodide, oleylamine iodide, phenylethyl ammonium bromide, oleylamine chloride, ethylenediamine iodide, propylenediamine iodide, and lithium fluoride.

[0064] Furthermore, the passivation layer can be prepared by any one of spin coating, blade coating, slot coating, inkjet printing, or vacuum evaporation.

[0065] The electron transport layer material is C. 60 Any one or more of the following materials: PCBM, zinc oxide, tin oxide, and titanium oxide.

[0066] Furthermore, the electron transport layer can be prepared by any of the following methods: spin coating, blade coating, slot coating, inkjet printing, vacuum evaporation, or atomic layer deposition.

[0067] The back electrode layer material can be any one or more of ITO, IZO, Au, Ag, Al, Cu, and carbon electrode materials.

[0068] Furthermore, the back electrode layer can be prepared by any one of vacuum evaporation, magnetron sputtering, screen printing, or inkjet printing.

[0069] The third embodiment of the present invention:

[0070] The purpose of this embodiment is to solve the problem of poor wettability of perovskite solution coated on flexible substrates, thereby improving the efficiency of flexible perovskite solar cells.

[0071] This embodiment of a method for preparing a flexible perovskite solar cell includes the following steps:

[0072] Step 1: Laser scribing P1 is performed on the flexible conductive substrate. The flexible substrate with laser scribing P1 is placed in a cleaning machine for cleaning. After cleaning, it is subjected to ultraviolet ozone surface treatment for 15 minutes and then taken out for use.

[0073] Step 2: The prepared flexible conductive substrate is used to prepare a hole transport layer NiOx by vacuum sputtering deposition equipment (PVD). The sputtering power is 1KW, the thickness of NiOx is 13nm, and the process temperature is 100℃ to obtain the NiOx hole transport layer.

[0074] NiOx of a specific thickness (13 nm) was sputtered onto a flexible substrate at a low temperature (100 °C). This thickness is the result of optimization; too thin a layer would lead to uneven coverage, while too thick a layer would increase series resistance and make the substrate prone to cracking when bent.

[0075] Step 3: Coat the surface of the NiOx hole transport layer prepared in Step 2 with an ethanol-dissolved MeO-2PACz self-assembled monolayer as the hole transport layer. The coating speed is 10 mm / s. Take 32 μL of MeO-2PACz ethanol solution and then anneal it on a hot stage at 100℃ for 10 min to obtain the MeO-2PACz self-assembled monolayer.

[0076] A self-assembled monolayer (MeO-2PACz) was constructed on an inorganic NiOx layer, forming a composite structure of "rough inorganic framework / smooth organic interface".

[0077] Steps 2 and 3 first construct a NiOx substrate, providing a stable and high work function for the SAM. Simultaneously, its nanoscale roughness increases the specific surface area, facilitating the firm anchoring of the SAM. NiOx provides excellent chemical stability and a basis for hole extraction, while the SAM precisely modulates the final interfacial energy level, making it more compatible with the valence band top of the perovskite, thus significantly improving the open-circuit voltage (Voc) of the battery. Furthermore, the surface energy modified by the SAM molecules is more conducive to the subsequent spreading of the perovskite solution, forming a pre-emptive synergy with the core innovation.

[0078] Step 4: Weigh 10 mg of sodium dodecyl phosphate, 4610 mg of lead iodide, 1548 mg of formamidine iodide (FAI), and 290 mg of cesium iodide, dissolve them in 9 mL of DMF and 1 mL of NMP to prepare 10 mL of perovskite precursor solution, which serves as the experimental group; weigh 4610 mg of lead iodide, 1548 mg of formamidine iodide (FAI), and 290 mg of cesium iodide, dissolve them in 9 mL of DMF and 1 mL of NMP to prepare 10 mL of perovskite precursor solution, which serves as the control group.

[0079] This step is one of the core innovations of this embodiment. It lies not only in the addition of anionic surfactants, but also in:

[0080] Specific choice: Sodium dodecyl phosphate.

[0081] Precise concentration: The optimal concentration range (0.08% to 0.15%, 0.1% in the example) was determined in complex component solutions (PbI2, FAI, CsI).

[0082] Solvent system synergy: This additive is optimized for the specific high-boiling-point solvent system "DMF / NMP (9:1)".

[0083] Creativity:

[0084] This step addresses not only the "wetting" issue, but also the relationship between the dodecyl phosphate group and the perovskite precursor (especially Pb).2+ There are strong interactions between them, which can regulate crystallization kinetics and initially affect crystal nucleus formation.

[0085] Step 5: The perovskite precursor solution prepared in Step 4 is injected into the coating equipment through the injection system. The coating head height is 150 μm and the coating speed is 10 mm / s. After coating, a perovskite wet film is obtained.

[0086] The use of blade coating, a process suitable for large-area preparation, and the limitation of blade height (150μm) and speed (10mm / s) together determine the thickness and uniformity of the wet film.

[0087] Step 6: Place the perovskite wet film obtained in Step 5 in a vacuum flash furnace. The vacuum flash evaporation is configured to be reduced to 10 Pa in 10 seconds, and the total flash evaporation time is set to 20 seconds. After the flash evaporation is completed, a dry perovskite film is obtained. Then, it is placed on a hot stage heated to 100°C for annealing for 20 minutes. After annealing, it is removed and allowed to cool naturally to obtain the perovskite film.

[0088] The drying conditions were set to drop to 10 Pa within 10 seconds and maintain this state for 20 seconds.

[0089] Steps 5 and 6 must be closely linked, meaning flash evaporation must occur immediately after coating (within 60 seconds). This is a precisely controlled process involving spatiotemporal coupling.

[0090] Synergistic mechanism:

[0091] The additive in step 4 reduces the surface tension of the solution, enabling a uniform initial liquid film to be formed after scraping.

[0092] Step 6, rapid flash evaporation, utilizes the improved uniformity of the liquid film after the addition of additives, and creates a huge number of nucleation sites in the liquid film instantly through rapid solvent escape.

[0093] This avoids component segregation (uneven Cs / I distribution) and random growth of large grains, ultimately resulting in a high-quality thin film with dense, uniform, and small-sized grains.

[0094] If step 4 is omitted (without additives), flash evaporation will cause severe film shrinkage and cracking; if step 6 is omitted (and slow thermal annealing is used instead), additive molecules will have enough time to migrate to the interface, potentially forming an insulating layer, and component segregation cannot be suppressed. Only the combination of "specific additives" and "specific flash evaporation process" can produce unexpected synergistic film-forming effects.

[0095] Step 7: Weigh 5 mg of PEAI drug, add 10 mL of isopropanol solvent in a glove box to prepare a 0.5 mg / mL passivation layer solution, shake to fully dissolve it, and then coat the PEAI passivation layer onto the perovskite film prepared in step 6 at a coating speed of 20 mm / s. After coating, place it on a hot plate heated to 100°C for annealing for 5 min to obtain the perovskite passivation layer.

[0096] A low-concentration (0.5 mg / mL) isopropanol solution of PEAI was applied to the formed perovskite film. Isopropanol does not dissolve the underlying perovskite, and PEAI molecules can selectively passivate halogen vacancy defects on the perovskite grain surface and grain boundaries.

[0097] This step is highly dependent on the high-quality, uniform substrate film produced in steps 4 and 6. If the substrate film itself is porous, the PEAI solution can seep into the pores, causing short circuits, or form an uneven coating, which in turn hinders charge transport.

[0098] It is a "post-repair" performed after perovskite crystallization, which, together with the "pre-regulation" of additives in step 4 during the crystallization process, forms a "process-post-treatment" dual defect control strategy, which together reduces the defect density of the perovskite layer to the minimum.

[0099] Step 8: Apply an electron transport layer C to the passivation layer obtained in Step 7 using a vacuum evaporation method. 60 For preparation, the sample is placed on a matching mask and subjected to a vacuum of 6*10⁻⁶. -4 Under the condition of Pa The rate is achieved by evaporating approximately 20 nm of C using a linear evaporation source. 60 A thin film was used to prepare an electron transport layer.

[0100] Low-temperature vacuum evaporation is used to avoid thermal damage to the underlying perovskite and passivation layers.

[0101] Step 9: A hole-blocking layer (SnO2) is prepared on the electron transport layer surface obtained in Step 8 using atomic layer deposition (ALD). The sample is placed in a process vacuum chamber, with the chamber temperature set to a stable 80°C. The tin source is TDMASn, the oxygen source is pure water, the outlet temperature is 65°C, and the number of purging cycles is 80. The hole-blocking layer is thus prepared.

[0102] SnO2 hole-blocking layers were prepared by ALD at ultra-low temperature (80℃). ALD technology enables the production of pinhole-free films with excellent shape retention, perfectly covering rough C4 substrates. 60 / Perovskite surface.

[0103] Steps 8 and 9 together construct a highly efficient dual-function structure for electron extraction and hole blocking.

[0104] C 60 The SnO2 electrode is responsible for efficiently extracting electrons, while SnO2, due to its deep valence band energy level, can effectively block holes from reaching the back electrode. Together, they significantly reduce the dark current and carrier recombination of the device, and improve the fill factor (FF) and open circuit voltage (Voc).

[0105] All low-temperature processes ensure complete compatibility with flexible substrates, as any high-temperature step would cause the flexible substrate to shrink, deform, or degrade.

[0106] Step 10: A transparent conductive electrode, ITO, is fabricated on the hole-blocking layer obtained in Step 9 using a vacuum sputtering deposition (PVD) system. After fixing the sample on the substrate holder, it is fed into the deposition chamber via the equipment's transmission system. Once the set vacuum level is reached, the sputtering process is performed. The sputtering power is set to 1 kW, using an argon-oxygen mixture (oxygen content 10%), and the ITO thickness is 20 nm, thus obtaining a transparent ITO electrode. Subsequently, a Cu metal electrode is sputtered at a power of 7 kW, achieving a Cu thickness of 80 nm, thus obtaining a Cu metal electrode.

[0107] Through a specific combination of these steps, this embodiment of the invention achieves an overall technical effect of 1+1>2: over a large area (427.5cm²). 2 A power conversion efficiency of over 16% has been achieved on flexible batteries.

[0108] The following will use experimental data as an example to illustrate the effect of the preparation method in this embodiment.

[0109] Table 1: Battery performance parameters with and without sodium dodecyl phosphate

[0110] PCE (%) <![CDATA[V OC (V)]]> <![CDATA[J SC (mA cm -2 )]]> FF (%) <![CDATA[Area(cm 2 )]]> control group 10.22 28.95 0.57 61.89 427.5 experimental group 16.01 31.03 0.68 75.30 427.5

[0111] Table 1 shows the battery performance parameters prepared with or without the addition of sodium dodecyl phosphate in the examples.

[0112] Figure 1 The diagram shows the structure of the flexible perovskite solar cell in the embodiment. From bottom to top, each layer in the diagram consists of a PET / ITO layer, a NiOx layer, a SAM layer, a PVK layer, a PEAI layer, and a C layer. 60 Layer, SnO2 layer, ITO layer, Cu layer.

[0113] Figure 2 and Figure 3 Images shown are of perovskite films prepared with and without the addition of sodium dodecyl phosphate in the examples. Figure 2 and Figure 3As can be seen, the perovskite film prepared without sodium dodecyl phosphate exhibits an incomplete state due to the poor wettability of the perovskite solution on the conductive substrate, which greatly affects the uniformity of the film and the final efficiency of the battery; while the perovskite film prepared with sodium dodecyl phosphate exhibits a complete and uniform coverage, resulting in a better perovskite film.

[0114] Figure 4 The figure shows the JV curves of large-area flexible perovskite solar cells prepared with and without the addition of sodium dodecyl phosphate in the examples. As can be seen from the figure, by adding sodium dodecyl phosphate to improve the wettability of the perovskite solution, the energy conversion efficiency of the large-area flexible cell can reach over 16%, while the control group without sodium dodecyl phosphate shows a poorer energy conversion efficiency. This demonstrates the feasibility and usability of this method.

[0115] This embodiment utilizes the ability of anionic surfactants to alter the surface tension of perovskite precursor solutions, addressing the problem of poor wettability of perovskite solutions coated on flexible substrates, thereby improving the efficiency of flexible perovskite solar cells. This fabrication method enables flexible perovskite solar cells with a pore area of ​​427.5 cm². 2 Its energy conversion efficiency exceeds 16%.

[0116] The core of this embodiment lies in the combination of surfactant, blade coating, and vacuum flash evaporation processes, which are specifically designed for large-area production. The blade coating process itself is suitable for large-area, continuous production; vacuum flash evaporation (reducing to 10 Pa within 10 seconds) works synergistically with the surfactant, inducing explosive and uniform nucleation of perovskites through the instantaneous and intense evaporation of the solvent, effectively suppressing component segregation that is prone to occur during slow drying, thus enabling the acquisition of uniform films even on large areas.

[0117] This embodiment establishes a complete low-temperature fabrication process, with all process steps conducted at temperatures not exceeding 100°C (e.g., NiOx sputtering, SAM annealing, perovskite annealing, PEAI annealing). Furthermore, the electron transport layer and hole blocking layer employ a low-temperature ALD process at 80°C. The entire process is fully compatible with high-temperature-sensitive flexible polymer substrates (such as PET, which typically withstands temperatures <150°C), avoiding substrate shrinkage, deformation, or degradation caused by high temperatures, thus ensuring device yield and reliability.

[0118] This embodiment improves the process window and repeatability: the addition of surfactants enhances the wettability of the precursor solution, making the coating process more tolerant of substrate micro-irregularities. The rapid vacuum flash evaporation process reduces interference from environmental factors (such as humidity and temperature fluctuations). This technical solution lowers the technical threshold and environmental requirements for preparing high-quality perovskite thin films, and improves process repeatability and product yield in mass production.

[0119] Fourth embodiment of the present invention:

[0120] A flexible perovskite solar cell of this embodiment is prepared by any of the preparation methods described above.

[0121] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0122] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a flexible perovskite thin film, characterized in that: Includes the following steps: Step 1: Prepare a perovskite precursor solution, wherein the perovskite precursor solution contains an anionic surfactant for reducing the contact angle of the solution on a flexible hydrophobic substrate, and the amount of the anionic surfactant added is 0.05% to 0.3% of the total mass of the solution; Step 2: Coat the perovskite precursor solution onto a flexible conductive substrate to form a wet film; Step 3: Immediately after coating, the wet film is subjected to vacuum flash evaporation treatment. The process conditions for vacuum flash evaporation treatment are: reducing the ambient pressure from atmospheric pressure to below 8-12 Pa within 8-12 seconds and maintaining it for 10-30 seconds. Step 4: Anneal the film after vacuum flash evaporation to form the flexible perovskite film.

2. The method for preparing a flexible perovskite thin film as described in claim 1, characterized in that, The anionic surfactant is one or more of the following: sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium dodecyl phosphate, sodium α-olefin sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl ether sulfate, sodium lauryl sulfate, and fatty alcohol phosphate salts.

3. The method for preparing a flexible perovskite thin film as described in claim 2, characterized in that, The anionic surfactant is sodium dodecyl phosphate.

4. A method for preparing a flexible perovskite solar cell, characterized in that: Includes the following steps: Step 1: Laser scribing P1 is performed on the flexible conductive substrate, followed by cleaning and ultraviolet ozone surface treatment; Step 2: Prepare a NiOx hole transport layer on the flexible conductive substrate by vacuum sputtering; Step 3: Coat a MeO-2PACz self-assembled monolayer on the NiOx hole transport layer to form a composite hole transport structure; Step 4: Prepare a perovskite precursor solution containing an anionic surfactant, wherein the anionic surfactant is sodium dodecyl phosphate, and the amount added is 0.05% to 0.3% of the total mass of the perovskite precursor solution. Step 5: The perovskite precursor solution prepared in Step 4 is coated onto the composite hole transport structure by a scraping method to form a perovskite wet film. Step 6: Perform vacuum flash evaporation on the perovskite wet film, followed by annealing to form a perovskite light-absorbing layer; Step 7: Coat the perovskite light-absorbing layer with PEAI passivation layer solution and perform annealing treatment to form a passivation layer; Step 8: Vacuum vapor deposition of C onto the passivation layer 60 Electron transport layer; Step 9: In the C 60 SnO2 hole blocking layer is prepared on electron transport layer by atomic layer deposition; Step 10: Sequentially prepare an ITO transparent electrode and a Cu metal electrode on the SnO2 hole blocking layer.

5. The method for preparing a flexible perovskite solar cell as described in claim 4, characterized in that, In step 2, the vacuum sputtering process conditions include: sputtering power of 0.8–1.2 kW, NiOx thickness of 10–15 nm, and process temperature of 80–120 °C; in step 3, the coating speed of the MeO-2PACz self-assembled monolayer is 8–12 mm / s, the amount is 30–35 μL, and the annealing conditions are annealing at 80–120 °C for 8–12 minutes.

6. The method for preparing a flexible perovskite solar cell as described in claim 4, characterized in that, In step 4, the perovskite precursor solution is prepared by dissolving sodium dodecyl phosphate, lead iodide, formamidinium iodide and cesium iodide in a mixed solvent of DMF and NMP, wherein the volume ratio of DMF to NMP is 9:1, and the amount of sodium dodecyl phosphate added is 0.1% of the total mass of the solution.

7. The method for preparing a flexible perovskite solar cell as described in claim 4, characterized in that, In step 5, the process parameters for the blade coating include: a blade height of 140–160 μm and a coating speed of 8–12 mm / s; in step 6, the process conditions for the vacuum flash treatment are: reducing the pressure from atmospheric pressure to below 8–12 Pa within 8–12 seconds and maintaining this pressure for 10–30 seconds; and the annealing treatment is performed at 100°C for 18–22 minutes.

8. The method for preparing a flexible perovskite solar cell as described in claim 1, characterized in that, In step 7, the concentration of the PEAI passivation layer solution is 0.4–0.6 mg / mL, the solvent is isopropanol, the coating speed is 18–22 mm / s, and the annealing conditions are annealing at 80–120°C for 4–6 minutes. In step 8, the vacuum evaporation C 60 The process conditions include: a vacuum degree of 6×10 -4 Pa, evaporation rate is The film thickness is 18-22 nm; in step 9, the process conditions for atomic layer deposition include: the chamber temperature is stable at 60-100°C, the tin source is TDMASn, the oxygen source is pure water, the outlet temperature is 60-70°C, and the number of purging cycles is 70-90.

9. The method for preparing a flexible perovskite solar cell as described in claim 1, characterized in that, In step 10, the fabrication process of the ITO transparent electrode includes: sputtering power of 0.8-1.2KW, oxygen content of 8-12% in the argon-oxygen mixture, and ITO thickness of 18-22nm; the fabrication process of the Cu metal electrode includes: sputtering power of 6-8KW, and Cu thickness of 60-100nm.

10. A flexible perovskite solar cell, characterized in that, It is prepared by the preparation method described in any one of claims 4 to 9 above.

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