Large-area flexible perovskite solar cell and preparation method thereof

Abstract

The invention discloses a large-area flexible perovskite solar cell and a preparation method thereof. The flexible perovskite solar cell sequentially comprises an ultrathin flexible tempered glass substrate, a bottom electrode, a NiOx hole transport layer, a PNPP and Me-4PACz common self-assembly molecular layer, a perovskite light absorption layer, an electron transport layer, a buffer layer, a top electrode and a bus bar from bottom to top. The preparation method comprises the steps of substrate fixing and cleaning, deposition of the bottom electrode and the hole transport layer, coating of the co-self-assembly molecular layer, preparation of the perovskite light absorption layer, evaporation of the electron transport layer and the tunneling layer, deposition of the top electrode, laser scribing, packaging and the like. The ultra-thin flexible tempered glass is adopted to solve the problem that a traditional substrate is insufficient in high temperature resistance and barrier property, interface defects are passivated through a PNPP and Me-4PACz co-self-assembly molecular layer, charge transfer is optimized, meanwhile, the mechanical flexibility of the device is improved, the efficiency of the prepared large-area device reaches 14.22%, the performance is stable after the device is bent for 6000 times, and the device is suitable for industrial application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cells, and particularly relates to a large-area flexible perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] Flexible perovskite solar cells have broad application prospects in wearable electronic devices and building photovoltaic integration due to their lightweight, bendable and portable advantages. However, there are still two major problems in the prior art that restrict its large-scale application: Firstly, the performance of the substrate material is limited. The conventional flexible substrate (such as PET) has poor high-temperature resistance and cannot withstand the high-temperature annealing process necessary in the preparation process of perovskite, resulting in poor quality of perovskite crystal growth. At the same time, the barrier property of such substrate is insufficient, which is easily eroded by external water vapor and oxygen, seriously affecting the stability and service life of the device, and greatly limiting the process selection and performance improvement of the device.

[0003] Secondly, the interface defects and mechanical brittleness are prominent. In the flexible device, there are interface defects between the perovskite light-absorbing layer and the charge transport layer (such as nickel oxide), which can significantly reduce the charge transfer efficiency and cause non-radiative recombination. In addition, during the bending process of the device, the stress distribution between the perovskite layer and the transport layer is uneven, and the interface adhesion is insufficient, resulting in easy breakage of the device and poor mechanical flexibility, which is difficult to meet the bending use requirements in actual application.

[0004] Self-assembled monolayers (SAMs) are a kind of organic molecules that can spontaneously form an ordered monolayer on the surface of a conductive substrate. Due to their adjustable work function, ultra-thin thickness (<5 nm), excellent stability and solution processing advantages, they are widely used as hole selective transport layers (HTL) in photovoltaic devices. However, studies have shown that the use of SAMs molecules alone has problems such as uncontrollable self-assembly state, uneven distribution at the molecular scale, and easy desorption by polar solvents on the NiO X substrate, resulting in poor wettability of the perovskite precursor solution, easy production of micropore defects during crystallization, and further aggravation of interface recombination problems. It cannot simultaneously solve the three major problems of substrate limitation, interface defects and mechanical brittleness, and it is difficult to achieve efficient and stable preparation of large-area flexible perovskite solar cells. SUMMARY

[0005] The purpose of the present application is to solve the problems of poor high-temperature resistance and barrier property of the substrate, low interface charge transfer efficiency, and poor mechanical flexibility in the existing flexible perovskite solar cell preparation technology, and to provide a large-area flexible perovskite solar cell and a preparation method thereof, so as to realize the synchronous improvement of the photoelectric conversion efficiency, stability, and mechanical reliability of the device by using an ultrathin flexible tempered glass as a substrate and forming a composite modification layer by co-self-assembly of PNPP and Me-4PACz to optimize the interface performance, and to meet the large-area industrial application requirements.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: A large-area flexible perovskite solar cell comprises, from bottom to top, a flexible substrate, a bottom electrode, a hole transport layer, a co-self-assembly molecular layer, a perovskite light-absorbing layer, an electron transport layer, a buffer layer, a top electrode, and a bus bar. The flexible substrate is an ultrathin flexible tempered glass with a thickness of 80-120 μm, and has the characteristics of high-temperature resistance, high barrier property, high flatness, and corrosion resistance. The co-self-assembly molecular layer is a composite modification layer of PNPP (4-nitrophenyl phosphonic acid) and Me-4PACz ([4-(3,6-dimethyl-9H-carbazol-9-yl)butyl] phosphonic acid).

[0007] The present application introduces PNPP into Me-4PACz to develop an effective Co-SAM composite modification layer, which optimizes the buried interface in F-PSCs. x The phosphonic acid group in PNPP can effectively inhibit the surface defects of NiO + , and the nitro group can enhance the wettability and passivate the organic cation and halide vacancy defects at the bottom of the perovskite film. The incorporation of PNPP not only improves the molecular rigidity, but also improves the perovskite crystallinity by strengthening the intermolecular interaction, reduces the residual stress, promotes the formation of denser films, improves the film morphology and composition uniformity, reduces the tensile stress, and improves the mechanical reliability.

[0008] As a further description of the above technical scheme, the molecular structure of the perovskite precursor solution of the perovskite light-absorbing layer is ABX3, wherein A is at least one of FA + , MA + , and Cs 2+ , B is at least one of Pb 2+ , and Sn - , and X is at least one of Cl - , Br - , and I.

[0009] As a further description of the above technical scheme, the hole transport layer is a nickel oxide (NiO xlayer, deposited by a magnetron sputtering process; the electron transport layer is a C 60 layer, prepared by an evaporation process; the buffer layer is a BCP layer with a thickness of 3-7 nm, deposited by an evaporation process.

[0010] As a further description of the above technical solution: the bottom electrode is an ITO layer with a thickness of 400-600 nm, prepared by a magnetron sputtering process; the top electrode is a 15-30 nm ITO transition layer and an 80-120 nm copper metal electrode deposited in sequence, prepared by a magnetron sputtering process; the bus bar is pasted on the two sides corresponding to the top electrode and the bottom electrode for leading out the positive and negative poles.

[0011] The application also provides a preparation method of the large-area flexible perovskite solar cell, comprising the following steps: (1) Substrate fixation and cleaning: fixing the ultra-thin flexible tempered glass on the rigid glass by high-temperature adhesive tape, and performing blowing and plasma cleaning treatment on the surface of the ultra-thin flexible tempered glass to remove surface impurities; (2) Bottom electrode and hole transport layer deposition: sputtering and depositing a bottom electrode on the surface of the cleaned ultra-thin flexible tempered glass, and continuously sputtering and depositing a hole transport layer on the bottom electrode; (3) First scribing: laser scribing P1 line to cut the bottom electrode and realize the partition isolation of the bottom electrode; (4) Co-self-assembled molecule layer coating: coating a mixed solution of PNPP and Me-4PACz on the surface of the hole transport layer to form a co-self-assembled molecule layer; (5) Perovskite light-absorbing layer coating: coating a perovskite precursor solution on the surface of the co-self-assembled molecule layer, and forming a perovskite light-absorbing layer after annealing treatment; (6) Electron transport layer and buffer layer preparation: sequentially evaporating an electron transport layer and a buffer layer on the surface of the perovskite light-absorbing layer; (7) Second scribing: laser scribing P2 line to cut the upper deposition of the bottom electrode and realize the preliminary separation of the battery unit; (8) Top electrode preparation: sequentially depositing a transition layer and a metal electrode on the buffer layer to form a top electrode; (9) Third scribing: laser scribing P3 line to cut the top electrode and complete the separation of the sub-battery; (10) Tearing off the high-temperature adhesive tape, pasting bus bars on both sides of the electrode and packaging.

[0012] As a further description of the above technical solution: in step (1), after the ultra-thin flexible tempered glass and the rigid glass are fixed, cold pressing is performed to ensure that the ultra-thin flexible tempered glass is flat without bulges.

[0013] As a further description of the above technical solution: the mixed solution of PNPP and Me-4PACz is obtained by mixing a methanol solution of PNPP and a methanol solution of Me-4PACz, the concentration of the methanol solution of PNPP is 0.05-0.2 mg / mL, and the concentration of the methanol solution of Me-4PACz is 0.3-0.8 mg / mL.

[0014] As a further description of the above technical solution: the mixed solution of PNPP and Me-4PACz is oscillated under nitrogen protection for 10-20 min before coating to make it fully mixed and uniform, and is stored in the dark to avoid photodegradation.

[0015] As a further description of the above technical solution: the perovskite precursor solution is obtained by dissolving a Pb salt and formamidinium iodide or a cesium salt in an organic solvent in any proportion; the molecular structure of the perovskite precursor solution is ABX3, wherein A is at least one of FA + , MA + , and Cs + , B is at least one of Pb 2+ and Sn 2+ , and X is at least one of Cl - , Br - , and I - .

[0016] As a further description of the above technical solution: the annealing temperature of the perovskite precursor solution is 120-180℃, and the annealing time is 20-40 min.

[0017] Compared with the prior art, the present application has the following beneficial effects: 1. The performance of the substrate is significantly improved: the present application uses ultra-thin flexible tempered glass as the substrate, which has much higher temperature resistance, high barrier property, high flatness and corrosion resistance than traditional PET substrates, can withstand the high-temperature annealing process in the perovskite preparation process, ensure high-quality crystallization of the thin film, effectively block the invasion of external water vapor and oxygen, and greatly improve the stability of the device; at the same time, the flexible property meets the bending use requirements of the device, and provides an ideal substrate for large-area preparation.

[0018] 2. The interface performance is significantly optimized: the composite modification layer formed by the co-self-assembly of PNPP and Me-4PACz integrates the small molecule PNPP into the self-assembled molecules, and a co-self-assembly monolayer (Co-SAM) strategy is proposed, the P=O and N-O groups in PNPP can target interact with the surface of NiO x and the uncoordinated metal ion defects at the bottom interface of the perovskite, wherein PNPP forms a ─P=O─Ni x bond with NiO 2+The Me-4PACz and the PNPP form a -N-O-Pb 2+ The Me-4PACz and the PNPP form a -N-O-Pb x The Me-4PACz and the PNPP form a -N-O-Pb x The Me-4PACz and the PNPP form a -N-O-Pb

[0019] 3、Mechanical reliability is greatly improved: the co-self-assembled molecular layer can strengthen the intermolecular interaction, improve the crystallinity of the perovskite, promote the formation of a dense film, and at the same time improve the stress distribution and interfacial adhesion of the perovskite layer, reduce the tensile stress, so that the device can still maintain good performance after 6000 bending cycles, and the bending resistance is significantly better than that of the traditional SAM device.

[0020] 4、Adapt to large-area industrialization: the preparation method of the present application adopts mature processes such as liquid coating, magnetron sputtering and evaporation, especially the liquid preparation method of the co-self-assembled molecular layer adapts to the coating process of the present large-area production, which is simple to operate and controllable in cost, and the prepared 300 mm x 300 mm large-area device has an effective area of 787 cm², which has the potential for large-scale application. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of the layered structure of the flexible perovskite solar cell of the present application.

[0022] Figure 2 is the structural formula of Me-4PACz and PNPP in the co-self-assembled molecular layer.

[0023] Figure 3 is a schematic diagram of the fixing method of the ultra-thin flexible tempered glass and the rigid glass.

[0024] Figure 4 is a schematic diagram of the structure of the flexible perovskite solar cell of the present application.

[0025] Figure 5 is a SEM image of the interface of the flexible perovskite solar cell of the present application after 6000 bending cycles.

[0026] Figure 6 is a SEM image of the interface of the traditional flexible perovskite solar cell after 6000 bending cycles.

[0027] In the figure: 1 - ultra-thin flexible tempered glass substrate, 2 - bottom electrode and hole transport layer, 3 - co-self-assembly molecule layer, 4 - perovskite light absorption layer, 5 - electron transport and buffer layer, 6 - top electrode, 7 - bus bar, 8 - POE encapsulation film. DETAILED DESCRIPTION

[0028] The claims of the present application will be further described in detail below in conjunction with the drawings and specific embodiments, but do not constitute any limitation on the present application, and any limited number of modifications made by anyone within the scope of protection of the claims of the present application is still within the scope of protection of the claims of the present application.

[0029] A large-area flexible perovskite solar cell with an area of 300 mm x 300 m has a structure as shown in Figure 1 and Figure 4 from bottom to top, including: thin flexible tempered glass substrate 1, bottom electrode and hole transport layer 2, co-self-assembly molecule layer 3, perovskite light absorption layer 4, electron transport and buffer layer 5, top electrode 6, bus bar 7 and POE encapsulation film 8; wherein the thickness of the ultra-thin flexible tempered glass substrate 1 is 100 μm, which has the characteristics of high temperature resistance, high barrier property, high flatness and corrosion resistance; the bottom electrode is an ITO layer with a thickness of 500 nm, which is deposited on the surface of the ultra-thin flexible tempered glass substrate 1 by magnetron sputtering process; the hole transport layer is a nickel oxide (NiO x ) layer with a thickness of 20 nm, which is deposited on the surface of the bottom electrode by magnetron sputtering process; the co-self-assembly molecule layer 3 is a composite modification layer of PNPP (4-nitrophenyl phosphoric acid) and Me-4PACz ([4- (3, 6-dimethyl-9H-carbazole-9-yl) butyl] phosphonic acid), which is prepared by coating a mixed solution of PNPP and Me-4PACz on the surface of the hole transport layer, wherein the structural formula of PNPP and Me-4PACz is as shown in Figure 2 ; the perovskite light absorption layer 4 is formed by coating a perovskite precursor solution on the surface of the co-self-assembly molecule layer 3 and annealing, the perovskite precursor solution is obtained by dissolving Pb salt and formamidine iodide or cesium salt in an organic solvent in any proportion, the molecular structure is ABX3, wherein A is at least one of FA + , MA + , Cs + , B is at least one of Pb 2+ , Sn 2+ , and X is at least one of Cl - , Br - , I - (this embodiment preferably FAPbI3); the electron transport layer is a C 60The buffer layer is a BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) layer with a thickness of 5 nm, which is prepared by a vapor deposition process; and the top electrode 6 is a 20 nm ITO transition layer and a 100 nm copper metal electrode, which are sequentially deposited and prepared by a magnetron sputtering process; and the bus bar 7 is attached to both sides of the electrode.

[0030] The preparation method comprises the following steps: (1) Substrate fixing and cleaning: Place a 300 mm x 300 mm, 100 μm thick ultra-thin flexible tempered glass on the rigid glass of the production line, and paste a 1 cm wide, 50 μm thick polyimide high-temperature adhesive tape around the ultra-thin flexible tempered glass. During the pasting process, ensure that the adhesive tape is uniformly pasted without bulging, slowly squeeze out the air between the flexible tempered glass and the rigid glass, and then place the combined body into a laminator for cold pressing operation to further ensure the flatness of the flexible tempered glass. After taking out, first clean the floating dust on the surface of the ultra-thin flexible tempered glass with a blowing device, and then put it into a plasma cleaning device for surface cleaning treatment to remove surface oil and oxide layer, as shown in FIG. 1; Figure 3 (2) Bottom electrode preparation: transfer the cleaned substrate to the magnetron sputtering equipment, adjust the sputtering parameters, and sputter an ITO layer with a thickness of 500 nm on the surface of the ultra-thin flexible tempered glass to form a bottom electrode; (3) Hole transport layer preparation: keep the vacuum environment of the magnetron sputtering equipment, replace the nickel oxide target, and continue to sputter a 20 nm thick nickel oxide (NiO x ) layer on the surface of the ITO bottom electrode as a hole transport layer; (4) Laser scribing P1 line: transfer the substrate with the deposited bottom electrode and hole transport layer to the laser scribing machine, set the scribing parameters, and use laser scribing to scribe P1 line to accurately cut the ITO layer and realize the partitioning of the bottom electrode; (5) Co-self-assembly molecule layer coating: weigh appropriate amounts of PNPP and Me-4PACz, dissolve them in methanol, and prepare a 0.1 mg / mL PNPP methanol solution and a 0.5 mg / mL Me-4PACz methanol solution. Mix the two solutions, place them in a nitrogen protection oscillator, and oscillate for 20 min to ensure uniform mixing. Then transfer them to a brown bottle for storage in the dark to prevent photodegradation. Use a coating device to uniformly coat the mixed solution on the surface of the NiO x hole transport layer to form a co-self-assembly molecule layer; ​(6) Coating of perovskite light-absorbing layer: Pb salt and formamidine iodide (or cesium salt) are dissolved in an organic solvent in any proportion (preferably a 1:1 molar ratio in this embodiment) to prepare a perovskite precursor solution with a molecular structure of ABX3 (preferably FAPbI3 in this embodiment). The perovskite precursor solution is uniformly coated on the surface of the self-assembled molecular layer using a coating device. Then the substrate is transferred to an annealing furnace and annealed at 150°C for 30 min to form a dense perovskite light-absorbing layer with high crystallinity. (7) Preparation of electron transport layer and buffer layer: The substrate with perovskite light-absorbing layer is transferred to the evaporation equipment, and after vacuuming, it is heated to C 60 An evaporation source was used to deposit a 15 nm thick C layer on the surface of the perovskite light-absorbing layer. 60 Electron transport layer; then replace the BCP evaporation source, at C 60 A 5 nm thick BCP buffer layer is then deposited on the surface of the electron transport layer. (8) Laser scribing of P2 lines: The substrate with deposited electron transport layer and buffer layer is transferred to the laser scribing machine, the scribing parameters are adjusted, and the P2 lines are scribed using laser to cut off the deposits on the ITO layer (including NiO). x Hole transport layer, co-self-assembled molecular layer, perovskite light-absorbing layer, C 60 (Electron transport layer and BCP buffer layer) to achieve initial separation of battery cells; (9) Top electrode fabrication: The substrate is transferred back to the magnetron sputtering equipment, and a 20 nm ITO transition layer and a 100 nm copper metal electrode are sputtered sequentially to form the top electrode; (10) Laser scribing of P3 line: The substrate with the deposited top electrode is placed back into the laser scribing machine, the scribing parameters are set, and the P3 line is scribed by laser to cut off the top electrode and complete the separation of the sub-cell. (11) Post-processing and encapsulation: Carefully peel off the polyimide high-temperature tape around the ultra-thin flexible tempered glass, gently remove the prepared battery device, and attach busbars to the corresponding sides of the top and bottom electrodes to lead out the positive and negative electrodes of the battery; finally, encapsulate the device with a POE encapsulation film to obtain a large-area flexible perovskite solar cell, such as Figure 4 As shown.

[0031] Performance testing: The performance of the large-area flexible perovskite solar cell (the device of this invention, using the Co-SAM scheme) prepared in this embodiment was compared with that of the conventional Me-4PACz single self-assembled modified flexible perovskite solar cell (the control device, using the conventional SAM scheme). The test results are shown in Table 1. The data comparison clearly shows that the effective area of ​​the devices is exactly the same (both are 787 cm²). 2Under the premise that the core performance of the device of the present invention is significantly better than that of the traditional SAM device: Power and efficiency improvements: Maximum rated power P max The power output increased from 7.1 W to 9.90 W, an improvement of approximately 39.4%; the device efficiency increased from 9.03% to 14.22%, an improvement of over 57%, directly demonstrating the optimization effect of the co-assembly scheme on photoelectric conversion capability; Electrical performance parameter optimization: short-circuit current J The open-circuit voltage was increased from 4.82 A to 6.21 A. V oc The voltage was increased from 36.95 V to 38.3 V, and the maximum power operating current / voltage also increased accordingly, proving that the Co-SAM scheme of this invention effectively improves the efficiency of charge generation, transport and extraction.

[0032] Table 1. Performance test results of the device of this invention and conventional SAM devices.

[0033] Simultaneously, bending stability tests were conducted on both devices: after 6000 bending cycles, the NiO content of the device of this invention was observed using a scanning electron microscope. x The / Me-4PACz+PNPP interface remains intact, with no obvious cracking or peeling. Figure 5 As shown; while traditional NiO x The interface of the / Me-4PACz monolayer modified SAM device exhibits obvious defects and thin film cracking, such as... Figure 6 As shown, this demonstrates that the device of the present invention also has significant advantages in mechanical reliability.

[0034] Based on the above test results, the device of this invention is superior to traditional SAM devices in terms of photoelectric conversion efficiency, output power, and mechanical stability, fully verifying the advanced nature and practicality of the technical solution.

[0035] In summary, the flexible perovskite solar cell of this invention is formed by sequentially depositing a hole transport layer, a co-self-assembled molecular layer, a perovskite light-absorbing layer, an electron transport layer, and a buffer layer on flexible tempered glass, and finally sputtering a metal electrode. The ultrathin flexible tempered glass possesses characteristics such as high temperature resistance, high barrier properties, high flatness, and corrosion resistance, and its overall performance far exceeds that of ordinary PET substrates, making it particularly suitable for high-temperature annealing after nickel oxide sputtering. In the complete perovskite preparation process, annealing and sputtering / evaporation processes are both critical steps, and the high-temperature resistance of flexible tempered glass provides ideal conditions for this. This invention integrates a small molecule PNPP into the self-assembled molecular SAM, proposing a co-self-assembled monolayer (Co-SAM) strategy to optimize the interface structure between nickel oxide and the perovskite layer, promoting the growth of perovskite crystals along a favorable orientation. This not only effectively suppresses the generation of surface and bulk perovskite defects but also significantly improves the interface charge transfer efficiency. Meanwhile, due to the more uniform stress distribution and enhanced interfacial adhesion of the perovskite layer, the bending resistance of flexible perovskite solar cell devices is also significantly improved, and high-efficiency perovskite solar cell devices with an efficiency of over 14% are fabricated on 300 mm × 300 mm flexible tempered glass.

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the present invention.

Claims

1. A large-area flexible perovskite solar cell, characterized in that, From bottom to top, it includes: a flexible substrate, a bottom electrode, a hole transport layer, a co-assembled molecular layer, a perovskite light-absorbing layer, an electron transport layer, a buffer layer, a top electrode, and a busbar; Its features are: The flexible substrate is an ultra-thin flexible tempered glass with a thickness of 80–120 μm; The aforementioned co-self-assembled molecular layer is a composite modified layer of PNPP and Me-4PACz.

2. The large-area flexible perovskite solar cell according to claim 1, characterized in that: The perovskite precursor solution of the perovskite light-absorbing layer has a molecular structure of ABX3, where A is FA. + MA + Cs + At least one of them, B is Pb 2+ Sn 2+ At least one of them, X is Cl - ,Br - I - At least one of them.

3. The large-area flexible perovskite solar cell according to claim 2, characterized in that: The hole transport layer is a nickel oxide layer with a thickness of 15–25 nm; the electron transport layer is a carbon oxide layer with a thickness of 10–20 nm. 60 The buffer layer is a BCP layer with a thickness of 3 to 7 nm.

4. The large-area flexible perovskite solar cell according to claim 3, characterized in that: The bottom electrode is an ITO layer with a thickness of 400–600 nm; the top electrode is an ITO transition layer with a thickness of 15–30 nm deposited sequentially and a copper metal electrode with a thickness of 80–120 nm.

5. The method for fabricating a large-area flexible perovskite solar cell according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Substrate fixation and cleaning: The ultra-thin flexible tempered glass is fixed to the rigid glass with high temperature tape, and the surface of the ultra-thin flexible tempered glass is blown and plasma cleaned to remove surface impurities; (2) Deposition of bottom electrode and hole transport layer: A bottom electrode is sputtered and deposited on the cleaned ultrathin flexible tempered glass surface, and a hole transport layer is sputtered and deposited on the bottom electrode. (3) First scribing: Laser scribing of P1 line, cutting off the bottom electrode, to achieve partition isolation of the bottom electrode; (4) Co-self-assembled molecular layer coating: A mixed solution of PNPP and Me-4PACz is coated on the surface of the hole transport layer to form a co-self-assembled molecular layer; (5) Coating of perovskite light-absorbing layer: The perovskite precursor solution is coated on the surface of the co-assembled molecular layer and annealed to form a perovskite light-absorbing layer. (6) Preparation of electron transport layer and buffer layer: Electron transport layer and buffer layer are sequentially deposited on the surface of perovskite light-absorbing layer; (7) Secondary scribing: Laser scribing of P2 line to cut off the deposit on the bottom electrode layer and achieve preliminary separation of battery cells; (8) Top electrode fabrication: A transition layer and a metal electrode are sequentially deposited on the buffer layer to form the top electrode; (9) Three-stage scribing: Laser scribing of the P3 line to cut off the top electrode and complete the separation of the sub-cell; (10) Remove the high-temperature tape, attach the busbars to both sides of the electrode and seal them.

6. The preparation method according to claim 5, characterized in that: In step (1), after the ultra-thin flexible tempered glass is fixed to the rigid glass, a cold pressing operation is performed to ensure that the ultra-thin flexible tempered glass is flat and free of bulges.

7. The preparation method according to claim 5, characterized in that: The mixed solution of PNPP and Me-4PACz in step (4) is formed by mixing a methanol solution of PNPP and a methanol solution of Me-4PACz. The concentration of the methanol solution of PNPP is 0.05 to 0.2 mg / mL, and the concentration of the methanol solution of Me-4PACz is 0.3 to 0.8 mg / mL.

8. The preparation method according to claim 7, characterized in that: The mixed solution of PNPP and Me-4PACz was shaken for 10-20 minutes under nitrogen protection before coating and stored away from light.

9. The preparation method according to claim 5, characterized in that: The perovskite precursor solution described in step (5) is obtained by dissolving Pb salt and formamidinium iodide or cesium salt in an organic solvent in any proportion; the molecular structure of the perovskite precursor solution is ABX3, where A is FA. + MA + Cs + At least one of them, B is Pb 2+ Sn 2+ At least one of them, X is Cl － ,Br － I － At least one of them.

10. The preparation method according to claim 9, characterized in that: The annealing temperature of the perovskite precursor solution is 120–180℃, and the annealing time is 20–40 min.

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