Flexible indoor photovoltaic cell module and preparation method and application thereof

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a flexible indoor photovoltaic battery assembly and a preparation method and application thereof. The preparation method of the flexible indoor photovoltaic cell module comprises the following steps: (1) carrying out P1 etching on an ITO substrate, and then carrying out ultrasonic treatment and drying to obtain a cleaned substrate; (2) sputtering the cleaned sediment to obtain a transmission layer; (3) depositing the assembled monomolecular layer on the transmission layer to obtain a thin film; (4) dissolving the perovskite precursor solution in a solvent, adding an additive, depositing by adopting a coating method, and then annealing to obtain a perovskite active layer thin film; (5) performing C60 deposition on the surface of the perovskite active layer thin film, and then depositing SnOx on the C60 surface; p2 etching is carried out; depositing a copper electrode on the surface of the perovskite active layer thin film; and then P3 etching is carried out to obtain a finished product. According to the preparation method provided by the invention, the performance of the assembly under indoor weak light can be remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a flexible indoor photovoltaic cell module, its preparation method, and its application. Background Technology

[0002] With the rapid development of the Internet of Things (IoT), smart homes, and wearable devices, indoor low-light photovoltaic (IPV) technology has emerged as a new direction in the renewable energy field. This technology utilizes indoor light sources (LEDs, fluorescent lamps, etc., 100-1000 lux) to power low-power electronic devices, offering advantages such as battery-free operation, self-powered operation, and sustainability. Due to its unique band structure and stability, it shows great potential in the field of indoor photovoltaics (IPV). Indoor low-light photovoltaics can be deposited at temperatures below 150°C, making them suitable for PET / PEN flexible substrates and meeting the needs of wearable electronics and smart homes. With collaborative innovation in materials, processes, and applications, indoor photovoltaics is expected to usher in a "battery-free electronics era" and become an important component of the green energy revolution.

[0003] Currently, the main strategy for achieving wide-bandgap perovskite materials is to replace some iodide ions with bromide ions in the perovskite composition. However, this indoor low-light photovoltaic system still faces key challenges in large-scale fabrication in air, such as halogen phase separation, solvent residue, and poor crystal quality, which severely restricts its commercialization. Uneven Br / I distribution: Under low indoor light, the concentration of photogenerated carriers is low, and halogen ions migrate more easily, forming an inactive phase, leading to performance degradation. Under illumination, iodide and bromide ions in wide-bandgap perovskites aggregate, resulting in phase separation. Phase separation leads to the formation of bromine-enriched and iodine-enriched regions, which become major carrier traps, severely reducing the efficiency and phase stability of indoor photovoltaics. Furthermore, defects on the perovskite surface also cause severe non-radiative recombination of carriers, further reducing the efficiency of wide-bandgap perovskite solar cells under indoor conditions.

[0004] Therefore, it is urgent to improve the phase stability of wide-bandgap perovskite materials and reduce the impact of surface defects on cell performance, thereby improving the efficiency of wide-bandgap perovskite indoor photovoltaics.

[0005] Relevant patent documents retrieved: For example, Chinese patent CN116887646A, published on July 18, 2023, discloses a flexible perovskite solar cell based on a full-slit coating process and its fabrication method, belonging to the field of perovskite solar cells. The fabrication method includes the following steps: sequentially fabricating a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a flexible conductive substrate using a full-solution slit coating method, or sequentially fabricating an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer on a flexible conductive substrate using the same method. The full-solution slit coating method used in this invention is simple and can save materials and costs to the greatest extent. Moreover, the flexible perovskite solar cell fabricated by this invention has excellent thermal and chemical stability, which will truly help realize the industrialization and marketization of flexible perovskite solar cells. However, the cell efficiency of this invention still needs to be improved.

[0006] Relevant non-patent literature retrieved: The journal or book title is *Journal of Chemical Industry and Engineering (China)*, and the article title is "Preparation of High-Performance Inorganic Perovskite Solar Cells Using Crystallization Quality Control Strategies," volume number 20251017.1859.002. This study introduced high-perovskite acid (HA) as a defect passivation additive into a wide-bandgap perovskite precursor solution, utilizing the carboxyl group and methoxy group containing lone pair electrons of HA to react with the Pb² of the perovskite. + The interaction reduces the defect state density of the thin film, improves perovskite crystallinity, and optimizes grain size. Ultimately, a perovskite solar cell (PSC) with a wide bandgap of 1.68 eV was fabricated, achieving a power conversion efficiency (PCE) of 20.60%. The corresponding open-circuit voltage (VOC), short-circuit current (JSC), and short-circuit current (FF) are 1.215 V, 21.33 mA cm⁻¹, and 1.215 V, respectively. -2 And 79.53%. Compared to the reference device without added HA (VOC=1.189 V, JSC=19.96 mA cm⁻¹). -2 The battery efficiency was improved (FF=78.08%), with all performance parameters showing improvement, including an 11.11% increase in PCE and a reduction in hysteresis (2.8% vs 1.6%). More importantly, the device with added HA exhibited good storage stability in a glove box at 85±0.5℃. However, the battery efficiency in this study still needs further improvement.

[0007] In solving the above problems or overcoming the above defects, the present invention encountered the following difficulties and obstacles: Using DMF:DMSO mixed solvents presents unique technical challenges, primarily stemming from issues such as Br / I ratio control, solvent residue, and phase separation. In low-light formulations, conventional DMSO exhibits strong hygroscopicity and a slow solvent evaporation rate. Prolonged exposure of DMSO to moisture exacerbates the hydration reaction, rapidly adsorbing water to form a DMSO-H2O complex. This disrupts the coordination equilibrium between DMSO and PbI2, interferes with the exchange of FAI (formamidinium iodide) and PbI2 molecules, leading to disordered crystallization and the formation of impurity phases.

[0008] One of the key technologies for achieving large-scale indoor low-light solar cell production in air is replacing DMSO with NEP, NMP, or GBL. This avoids moisture absorption caused by DMSO residue and extends the processing window. Another key technology is the combined use of infrared pre-annealing and additives. By incorporating additives such as CsPb(SCN)2Cl, KSCN, GASCN, and Pb(SCN)2, SCN- ions migrate directionally to the grain boundaries under the photothermal effect of an infrared furnace, regulating vertical growth, reducing grain boundaries, and optimizing orientation. SCN- ions occupy I vacancies, delaying crystallization, suppressing phase segregation, and blocking moisture adsorption points. An 80℃ infrared pre-annealing process forms a hydrophobic barrier. Infrared pre-annealing, with wavelengths of 900-1200nm, selectively heats the perovskite phase (substrate temperature <50℃), completing solvent evaporation in 5-20 seconds, avoiding the moisture adsorption window, and providing low-temperature protection with a flexible substrate, adapting to flexible substrates. The above key technologies have enabled large-scale production of indoor photovoltaics in the air, significantly suppressed phase segregation problems, improved efficiency and stability in indoor photovoltaics, and promoted industrialization and application through a low-cost, scalable additive system. Summary of the Invention

[0009] The purpose of this invention is to provide a flexible indoor photovoltaic cell module, its preparation method and application, and related technologies to solve technical problems such as low cell efficiency and poor stability, or combinations thereof.

[0010] Terminology Explanation: Unless otherwise defined, all technical terms in this document have the same meanings as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains. Unless otherwise stated, all patents, patent inventions, and publications cited in this document are incorporated herein by reference in their entirety. If multiple definitions exist for terms in this document, the definitions in this chapter shall prevail.

[0011] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0012] The definition of standard chemical terminology can be found in the reference "Chemical Power Sources (Second Edition), Cheng Xinqun (Chief Editor)".

[0013] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0014] The term "perovskite precursor solution" as used in this article refers to a homogeneous solution formed by dissolving a perovskite material precursor in a solvent and adding a modifier, used to form a perovskite thin film on a substrate through a coating process. Essentially, it disperses the chemical components of perovskite in molecular or ionic form in a solvent, providing a "pre-formulation" for subsequent thin film crystallization.

[0015] As used herein, the term "slot coating" refers to a coating technique for applying solutions, slurries, or extruded films onto a flat substrate. This process involves dissolving or suspending the desired coating material in a precursor solution or slurry and delivering it to the substrate surface through a slot die. Controlled delivery of the coating liquid allows for the continuous production of wide coatings on the substrate. By controlling the solution deposition rate and the relative velocity between the solution and the substrate, thin material coatings ranging from 10 nanometers to 100 micrometers in thickness can be obtained.

[0016] The term "VCD" used in this article refers to Vacuum Flash Drying, which is one of the key core equipment urgently needed for the industrialization of perovskite batteries. It can produce high-quality perovskite thin films by precisely controlling the evaporation rate and deposition thickness of perovskite materials.

[0017] The term "magnetron sputtering" as used in this article refers to a sputtering deposition method that uses a magnetic field to confine the movement of electrons near a target surface. In the magnetron sputtering process, two planar electrodes are placed in a vacuum chamber: the target material serves as the cathode, and the substrate as the anode. A permanent magnet is placed on the cathode side to form a ring-shaped magnetic field. After a small amount of argon gas is introduced, a DC high-voltage electric field is applied to induce a glow discharge in the gas. Argon positive ions bombard the cathode target, causing it to sputter. The sputtered neutral target atoms or molecules are deposited on the substrate to form a thin film.

[0018] The term "PET / ITO / NiOx / Me-4PACz" used in this article refers to: PET, polyethylene terephthalate, a common polymer material; ITO, indium tin oxide, a transparent conductive oxide; NiOx, nickel oxide, which can be used as a hole transport layer material in perovskite solar cells; and Me-4PACz, a self-assembling molecule, such as 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethylphosphonic acid, which can form a strong coupling with NiOx to construct an integrated hole transport layer. PET / ITO / NiOx / Me-4PACz likely refers to a multilayer structure composed of these materials, commonly used in the fabrication of perovskite solar cells.

[0019] The term "substrate" as used in this article refers to the base material that serves as a support or starting layer during the material preparation or device manufacturing process. Other materials are usually deposited, grown, or coated on the substrate, such as glass and silicon wafers.

[0020] The term "conductive substrate" as used in this article refers to a substrate material with high electrical conductivity, such as doped silicon substrates and gallium arsenide substrates. Its conductivity is improved through specific doping processes, and it is often used in applications with high electrical performance requirements, such as semiconductor devices and solar cells.

[0021] The term "hole transport layer" used in this article refers to the layer located between the active layer and the anode, which promotes hole transport while suppressing reverse flow between holes and the cathode. It is one of the key components affecting the performance of solar cells. Commonly used hole transport layer materials include aqueous solutions of polymers composed of conductive polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonate (PSS).

[0022] The term "crystallization rate" used in this article refers to the speed at which the material crystallization process proceeds. It is expressed as the reciprocal of the time required for the crystallization process to proceed to the halfway point and is determined by the nucleation rate and the grain growth rate.

[0023] The term “film uniformity” as used in this article refers to the consistency of the properties of a film across the entire substrate. The most common measurement method is thickness uniformity, but it also includes the uniformity of other properties such as refractive index, density, or chemical composition.

[0024] The term "self-assembled monolayer" as used in this article refers to molecular assemblies that spontaneously form on a surface through adsorption of organic molecules. These molecules are organized into more or less ordered regions. Self-assembled monolayers typically consist of head groups, molecular chains, and terminal groups with specific functions. The head groups have a strong affinity for the substrate, which can anchor the molecules to the substrate.

[0025] The term "perovskite active layer" used in this article refers to the key functional layer in a perovskite solar cell that absorbs photons and generates electron-hole pairs. It is usually composed of materials with a perovskite structure, such as ABX3 type (A is an organic cation, B is a metal cation, and X is a halogen element) perovskite materials, and its performance directly affects the photoelectric conversion efficiency of the cell.

[0026] The term "electron transport layer" as used in this article refers to a layer of material located between the perovskite active layer and the cathode in a solar cell. Its main function is to collect and transport electrons generated in the perovskite active layer, while preventing holes from transporting to the cathode, so as to achieve effective separation and transport of electrons and holes and improve the photoelectric performance of the cell.

[0027] The term "metal top electrode" as used in this article refers to an important component of a solar cell, usually located at the top of the cell structure. It is generally made of a metal material with good conductivity and stability, such as silver or aluminum. Its function is to collect the current generated in the cell and lead the current out for external power supply.

[0028] The term "photovoltaic performance" used in this article refers to the ability and related characteristics of a solar cell to convert solar energy into electrical energy. It mainly includes parameters such as photoelectric conversion efficiency, open-circuit voltage, short-circuit current, and fill factor. These parameters reflect the power generation capacity and performance of solar cells under different light conditions.

[0029] In a first aspect, the present invention provides a method for preparing a flexible indoor photovoltaic cell module, comprising the following steps: (1) The ITO substrate was etched using P1 etching to separate multiple sub-cells from the bottom. After etching, ultrasonic cleaning and drying were performed to obtain the cleaned substrate; (2) Sputter the cleaned sediment to obtain the transport layer; (3) The self-assembled monolayer is deposited onto the transport layer to obtain a thin film; (4) Dissolve the perovskite precursor solution in a solvent, add additives, deposit it by coating method, and then anneal it to obtain a perovskite active layer film. (5) The surface of the perovskite active layer film is subjected to C 60 Deposition, followed by C 60 Surface deposition of SnO x Then P2 etching is performed; after etching, copper electrode deposition is performed on the surface of the perovskite active layer film; then P3 etching is performed to obtain the final product. The specific parameters of the coating method in step (4) are as follows: coating thickness: 140-160μm, pre-injection volume: 240-300μl, pre-injection speed: 50-70μL / s; coating speed: 10-15mm / s; injection speed: 24-30μL / s; vacuum flash drying (VCD): 8-12s to 8-12Pa, holding pressure for 35-45s.

[0030] Preferably, the etching in step (1) is performed using a red nanosecond laser to etch P1 cells, separating multiple sub-cells from the bottom; the laser wavelength is 1050-1100nm, and other specific values ​​within the above range can be selected to achieve the technical effect of the present invention, such as wavelengths including but not limited to 1050nm, 1060nm, 1062nm, 1064nm, 1066nm, 1068nm, 1070nm, 1080nm, 1090nm, and 1100nm.

[0031] More preferably, the wavelength of the red nanosecond laser used in step (1) is 1064 nm.

[0032] Preferably, the ultrasound time in step (1) is 5-10 min. Other specific values ​​within the above range can be selected to achieve the technical effect of the present invention. For example, the time includes but is not limited to 5 min, 6 min, 7 min, 8 min, 9 min, and 10 min.

[0033] Preferably, the drying in step (1) is done by air gun drying.

[0034] Preferably, the sputtering in step (2) is magnetron sputtering, and the sputtering parameters are: sputtering power: 1800-2200W, argon: 380-420sccm, oxygen: 1-3sccm, room temperature sputtering 2-4 cycles. Other specific values ​​within the above range can be selected, and all can achieve the technical effect of the present invention. For example, the power includes but is not limited to 1800W, 1900W, 2000W, 2100W, and 2200W.

[0035] More preferably, the sputtering parameters of the magnetron sputtering used in step (2) are: sputtering power: 2000W, argon: 400sccm, oxygen: 2sccm, 3 sputtering cycles at room temperature.

[0036] Preferably, the thickness of the transport layer obtained in step (2) is 18-22 nm, more preferably 20 nm.

[0037] Preferably, the self-assembled monolayer in step (3) is a Me-4PACz ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphate) solution with a concentration of 0.1-2 mg / mL and ethanol as the solvent. Other specific values ​​within the above range can be selected to achieve the technical effect of the present invention. For example, the solution concentration may include, but is not limited to, 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, and 2 mg / mL.

[0038] More preferably, the concentration of the solution for assembling the monolayer in step (3) is 0.5 mg / mL.

[0039] Preferably, the deposition method used in step (3) is slit coating, with the following specific parameters: coating speed 4-6 mm / s, liquid injection speed 5-10 μL / s, thickness 90-110 μm; annealing at 90-110℃ for 8-12 min. Other specific values ​​within the above range can be selected, and all can achieve the technical effect of the present invention. For example, coating speeds include, but are not limited to, 4 mm / s, 4.5 mm / s, 5 mm / s, 5.5 mm / s, and 6 mm / s.

[0040] More preferably, the specific parameters of the slit coating method used for deposition in step (3) are: coating speed 4-6 mm / s, liquid injection speed 8 μL / s, thickness: 100 μm; annealing at 100℃ for 10 min.

[0041] Preferably, the perovskite precursor solution in step (4) is composed of CsI, FAI, PbI2 and PbBr2, with a mass ratio of 60-65:160-170:220-225:260-265. Other specific values ​​within the above range can be selected, and all can achieve the technical effect of the present invention.

[0042] More preferably, the mass ratio of CsI, FAI, PbI2, and PbBr2 is 62.35:165.1:221.2:264.2.

[0043] Preferably, the solvent in step (4) is composed of DMF (N,N-dimethylformamide), NMP (N-methylpyrrolidone) and NEP (N-ethylpyrrolidone), with a mass ratio of 850-900:90-110:30-50. Other specific values ​​within the above range can be selected, and all can achieve the technical effect of the present invention.

[0044] More preferably, the mass ratio of DMF, NMP and NEP is 840:100:60.

[0045] Preferably, the additive in step (4) consists of RbSCN and KSCN in a molar ratio of 1-2:1.

[0046] More preferably, the molar ratio of RbSCN (rubidium thiocyanate) to KSCN (potassium thiocyanate) is 1:1.

[0047] Preferably, the specific parameters of the coating method are as follows: coating thickness: 150 μm, pre-injection volume: 280 μl, pre-injection speed: 60 μL / s; coating speed: 12 mm / s; injection speed: 28 μL / s; VCD: pump to 10 Pa in 10 s, hold pressure for 40 s.

[0048] Preferably, the annealing in step (4) is divided into two stages. The first stage is low-temperature pre-annealing, which uses an infrared light wave furnace with a wavelength of 800nm-1200nm, a low-temperature pre-annealing temperature of 60-100℃, and a pre-annealing time of 1-10min. The second stage is high-temperature annealing, with a temperature of 100-170℃ and an annealing time of 8-30min. Other specific point values ​​within the above range can be selected, and all can achieve the technical effect of the present invention.

[0049] More preferably, the annealing in step (4) is divided into two stages. The first stage is low-temperature pre-annealing, which uses an infrared light wave furnace with a wavelength of 920nm, a low-temperature pre-annealing temperature of 80℃, and a pre-annealing time of 1min. The second stage is high-temperature annealing, with a temperature of 150℃ and an annealing time of 20min.

[0050] Preferably, the thickness of the perovskite active layer film in step (4) is 550-750 nm.

[0051] Preferably, the C in step (5) 60 The deposition thickness is 10-20 nm, and the thermal evaporation method is used.

[0052] More preferably, the C in step (5) 60 The deposition thickness is 15 nm.

[0053] Preferably, the SnOx deposition thickness in step (5) is 20-30 nm, and the ALD in-situ atomic deposition method is used.

[0054] More preferably, the SnOx deposition thickness in step (5) is 25 nm.

[0055] Preferably, the P2 etching in step (5) is performed using a green picosecond laser to remove the electron transport layer, perovskite active layer, self-assembled monolayer and hole transport layer in the P2 region, which serve as the interconnection area between the metal top electrode and the flexible ITO bottom electrode.

[0056] Preferably, the copper electrode in step (5) has a deposition thickness of 140-160 nm and is deposited using a thermal evaporation method.

[0057] More preferably, the deposition thickness of the copper electrode in step (5) is 150 nm.

[0058] Preferably, the P3 etching in step (5) is performed using a green picosecond laser to cut off the P3 metal region and divide out multiple sub-cells from the top to obtain a large-area flexible indoor low-light perovskite solar module.

[0059] Secondly, the present invention also provides a photovoltaic cell module prepared by the above-described preparation method.

[0060] Thirdly, the present invention also provides the application of the photovoltaic cell module prepared by the above method in the preparation of indoor low-light perovskite solar cells.

[0061] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention discloses a process for large-area fabrication of flexible indoor photovoltaic solar modules in air. The process involves the combined use of solvent selection, additive selection, and infrared furnace pre-annealing in the perovskite active layer formulation. Choosing a suitable solvent combination improves the yield of perovskite mesophase films. Low-temperature pre-annealing followed by high-temperature annealing yields the perovskite film. The solvent selection ensures the production of dense and continuous films for industrial-scale fabrication in air. The further introduction of additives improves the crystallinity quality and phase segregation suppression of wide-bandgap perovskite production in air. The gradient annealing process combining additives and an infrared furnace optimizes the perovskite crystallization kinetics, further improving crystallinity quality and grain size. Based on this method, high-performance, large-area flexible indoor low-light solar cells have been successfully fabricated in an air environment.

[0062] 2. This invention discovers that by precisely controlling the thickness of the perovskite active layer on a flexible substrate within the range of 550-750 nm and synergistically optimizing the thickness of the self-assembled monolayer, the performance of the device under low-light indoor conditions can be significantly improved. The optimal effect is achieved when the thickness of the perovskite active layer is 600-700 nm. This optimization is achieved by adjusting parameters such as the injection rate of the slit coating.

[0063] 3. This invention explores the thickness window of the perovskite layer: For the first time, it clearly reveals that there is an optimal perovskite active layer thickness window (550-750nm) for indoor low-light photovoltaic applications, with the optimal window being 600-700nm. This thickness ensures sufficient light absorption while avoiding the high series resistance problem caused by excessively thick layers, achieving the best balance between photocurrent generation and charge collection efficiency under low light conditions.

[0064] 4. Synergistic Optimization Strategy: A synergistic optimization concept for the thickness of the perovskite active layer and the self-assembled monolayer is proposed. By adjusting the coating parameters of the self-assembled monolayer (injection rate 5-10 μL / s) to achieve the optimal thickness, efficient hole extraction is ensured, perfectly matching the optimized thick active layer and jointly improving device performance.

[0065] 5. Strong correlation between process and structure: A repeatable and scalable preparation method was established to precisely achieve the optimal functional layer thickness by controlling key process parameters of slot coating (especially injection speed). This strongly correlates and protects the scientific discovery of "how thick to make" with the process technology of "how to make this thickness". Detailed Implementation

[0066] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0067] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0068] Example 1: A method for preparing a flexible indoor photovoltaic cell module The specific steps are as follows: (1) P1 etching was performed on a flexible ITO substrate using a red nanosecond laser to separate multiple sub-cells from the bottom; the laser wavelength was 1064nm; after P1 etching was completed on the PET / ITO substrate, it was ultrasonically cleaned with detergent, water and ethanol for 5 minutes in sequence, and then dried with an air gun. (2) The cleaned flexible substrate was placed in a magnetron sputtering device with a sputtering power of 2000W, argon gas of 400sccm, oxygen gas of 2sccm, and sputtered at room temperature for 3 cycles to obtain a 20nm thick NiOx hole transport layer. (3) Assemble the monolayer as Me-4PACz solution with a concentration of 0.5 mg / mL and ethanol as solvent. Deposit the Me-4PACz solution onto the NiOx transport layer by slit coating method with a gap of 100 μm, a pre-filled liquid volume of 240 μL, a pre-filled liquid rate of 40 μL / s, a coating speed of 5 mm / s, and a liquid filling speed of 8 μL / s. Anneal at 100℃ for 10 min to obtain Me-4PACz film. (4) Dissolve the indoor weak-light perovskite precursor solution composed of 62.35 mg CsI, 165.1 mg FAI, 221.2 mg PbI2, and 264.2 mg PbBr2 in a mixed solvent of DMF:NMP:NEP = 840:100:60, and add 2% mol The RbSCN + 2% molKSCN mixed additive was dissolved in the precursor solution and filtered before use; coating thickness: 150 μm, pre-injection volume: 280 μL, pre-injection speed: 60 μL / s; coating speed: 12 mm / s; injection speed: 28 μL / s; VCD: pumped to 10 Pa in 10 s, held at 10 Pa for 40 s; immediately, a first stage of low-temperature pre-annealing was performed in an infrared light wave furnace (wavelength 800 nm-1200 nm) at 80 °C for 5 min; in the second stage, the perovskite film was placed face down on a heating plate, ensuring a certain distance between the film and the heating plate; then, high-temperature annealing was performed at 150 °C for 20 min to obtain a perovskite active layer film with a thickness of 625 nm; (5) A 15 nm C layer was deposited on the surface of the perovskite active layer using a thermal evaporation method. 60 (full fillerene); ALD in-situ atomic deposition was used to deposit C... 60 A 25nm SnOx layer is deposited on the surface. A green picosecond laser is used for P2 etching to remove the electron transport layer, perovskite active layer, self-assembled monolayer, and hole transport layer in the P2 region, which will serve as the interconnection area between the metal top electrode and the flexible ITO bottom electrode. A 150nm copper electrode is deposited on the surface of the perovskite active layer using thermal evaporation. A green picosecond laser is used for P3 etching to cut off the P3 metal region and divide multiple sub-cells from the top, resulting in a large-area flexible indoor low-light perovskite solar module.

[0069] Example 2 The difference from Example 1 is that the pre-injection volume in step (4) is 240 μL, the injection speed is 24 μL / s, and the thickness of the obtained perovskite active layer film is 575 nm. The rest are the same as in Example 1.

[0070] Example 3 The difference from Example 1 is that the pre-injection volume in step (4) is 300 μL, the injection speed is 30 μL / s, and the thickness of the obtained perovskite active layer film is 675 nm. The rest are the same as in Example 1.

[0071] Example 4 The difference from Example 1 is that the pre-injection volume in step (3) is 260 μL, the pre-injection speed is 30 μL / s, the coating speed is 4 mm / s, and the injection speed is 10 μL / s. The rest are the same as in Example 1.

[0072] Example 5 The difference from Example 1 is that the pre-injection volume in step (3) is 220 μL, the pre-injection speed is 50 μL / s, the coating speed is 6 mm / s, and the injection speed is 5 μL / s. The rest are the same as in Example 1.

[0073] Comparative Example 1 The difference from Example 1 is that the pre-injection volume in step (4) is 220 μL, the injection rate is 22 μL / s, and the thickness of the resulting perovskite active layer film is 525 nm. The rest are the same as in Example 1.

[0074] Comparative Example 2 The difference from Example 1 is that the pre-injection volume in step (3) is 210 μL and the pre-injection speed is 20 μL / s, while the rest is the same as in Example 1.

[0075] Comparative Example 3 The difference from Example 1 is that the pre-injection volume in step (4) is 340 μL, the injection speed is 34 μL / s, and the thickness of the obtained perovskite active layer film is 750 nm. The rest are the same as in Example 1.

[0076] Comparative Example 4 The difference from Example 1 is that the pre-injection volume in step (4) is 320 μL, the injection speed is 32 μL / s, and the thickness of the obtained perovskite active layer film is 725 nm. The rest are the same as in Example 1.

[0077] Effect Experiment Slit coating, single piece area 35*35 cm 2 Each piece measures 35*35 cm. 2 Nine 10*10cm sections were divided using laser technology. 2 Small component, 10*10cm 2 The small component has an aperture area of ​​88.47 cm². 2 The device performance was tested by simulating low-light indoor illumination with a 3000K light source at a light intensity of 200 Lux. The fabricated flexible indoor photovoltaic module was tested, and the test indicators included photoelectric conversion efficiency (Eff), open-circuit voltage (Voc), short-circuit current (Isc), and fill factor (FF), which were obtained by direct measurement readings from the perovskite low-light photovoltaic performance testing system. The obtained photovoltaic performance parameters are shown in Table 1.

[0078] Table 1

[0079] The results show that optimizing the perovskite phase thickness and the interface layer thickness in the embodiments of the present invention is key to achieving ultra-high efficiency (>34%). The thickness of the SAM layer needs to be precisely controlled. Too thick or too thin a layer will impair performance. This indicates that there is an optimal thickness coverage window for the SAM layer.

[0080] For indoor low-light perovskite solar cells, controlling the thickness of the perovskite light-absorbing layer to 600-700 nm achieves the optimal performance balance, resulting in a conversion efficiency exceeding 35%. This embodies the innovative concept of co-designing the bulk phase and interface.

[0081] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a flexible indoor photovoltaic cell module, characterized in that, Includes the following steps: (1) The flexible ITO substrate is etched with a nanosecond laser to separate multiple sub-cells from the bottom; After etching, the substrate is ultrasonically cleaned and then dried to obtain a cleaned substrate. (2) Sputter the cleaned sediment to obtain the transport layer; (3) The self-assembled monolayer is deposited onto the transport layer to obtain a thin film; (4) Dissolve the perovskite precursor solution in a solvent, add additives, deposit it by coating method, and then anneal it to obtain a perovskite active layer film. (5) The surface of the perovskite active layer film is subjected to C 60 Deposition, followed by C 60 Surface deposition of SnO x Then P2 etching is performed; after etching, copper electrode deposition is performed on the surface of the perovskite active layer film; then P3 etching is performed to obtain the final product. The specific parameters of the coating method described in step (4) are as follows: coating thickness: 140-160μm, pre-injection volume: 240-300μL, pre-injection speed: 50-70μL / s; coating speed: 10-15mm / s; injection speed: 24-30μL / s; vacuum flash drying: 8-12s to 8-12Pa, pressure held for 35-45s.

2. The preparation method according to claim 1, characterized in that, The sputtering in step (2) is magnetron sputtering with the following sputtering parameters: sputtering power: 1800-2200W, argon: 380-420sccm, oxygen: 1-3sccm, room temperature sputtering 2-4 cycles.

3. The preparation method according to claim 1, characterized in that, The deposition method used in step (3) is the slot coating method, with the following specific parameters: pre-injection volume 220-260 μL, pre-injection speed 30-50 μL / s; coating speed 4-6 mm / s, injection speed 5-10 μL / s, thickness 90-110 μm; annealing at 90-110℃ for 8-12 min.

4. The preparation method according to claim 1, characterized in that, The perovskite precursor solution in step (4) is composed of CsI, FAI, PbI2 and PbBr2, with a mass ratio of 60-65:160-170:220-225:260-265.

5. The preparation method according to claim 1, characterized in that, The solvent in step (4) consists of DMF, NMP and NEP, with a mass ratio of 850-900:90-110:30-50.

6. The preparation method according to claim 1, characterized in that, The additive described in step (4) consists of RbSCN and KSCN in a molar ratio of 1-2:

1.

7. The preparation method according to claim 1, characterized in that, The specific parameters of the coating method are as follows: coating thickness: 150 μm, pre-injection volume: 280 μL, pre-injection speed: 60 μL / s; coating speed: 12 mm / s; injection speed: 28 μL / s; vacuum flash drying: evacuate to 10 Pa in 10 s, and hold pressure for 40 s.

8. The preparation method according to claim 1, characterized in that, The annealing in step (4) is divided into two stages. The first stage is low-temperature pre-annealing, which uses an infrared light wave furnace with a wavelength of 800nm-1200nm. The low-temperature pre-annealing temperature is 60-100℃ and the pre-annealing time is 1-10min. The second stage is high-temperature annealing, with a temperature of 100-170℃ and an annealing time of 8-30min.

9. A photovoltaic cell module prepared by the preparation method according to any one of claims 1-8.

10. The application of the photovoltaic cell module prepared by the preparation method according to any one of claims 1-8 in the preparation of indoor low-light perovskite solar cells.

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