Composition for improving performance of perovskite active layer and application thereof

Abstract

The invention discloses a composition for improving performance of a perovskite active layer and application thereof, and belongs to the technical field of solar cells. The technical problems to be solved are that a perovskite material is poor in humidity and thermal stability, the structure of the perovskite material can be destroyed under the conditions of high temperature and existence of water vapor to cause perovskite decomposition, and a prepared perovskite thin film is poor in stability. According to the technical scheme, the method is characterized in that a perovskite precursor solution is prepared by adopting a specific additive combination and a proportion thereof, volatilization of a solvent is completed, and a moisture adsorption window period is avoided. Through multi-solvent mixing, local drying and additive optimization, the reliability and repeatability of outdoor processing can be further improved, crystallization and phase segregation inhibition of perovskite can be delayed, the performance and stability of an indoor weak-light photovoltaic module can be greatly improved, and large-scale production of perovskite indoor photovoltaics can be promoted.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and more specifically, relates to a composition for improving the performance of perovskite active layers and its application. Background Technology

[0002] Renewable energy sources are widely distributed, abundant, and environmentally friendly, making their widespread adoption imperative. Renewable energy sources mainly include wind power, hydropower, bioenergy, and solar energy. Among these, solar energy possesses enormous development potential due to its convenient and rapid acquisition, pollution-free operation, and inexhaustible resources. Solar energy is generated by nuclear fusion within the sun, producing radiation energy equivalent to 5 million tons of coal every second. Currently, various new technologies are continuously being developed in the application of solar energy.

[0003] Solar photovoltaic power generation, as one of the most promising solutions to replace fossil fuels, has achieved leapfrog development in recent years. First-generation solar cells: silicon-based solar cells; second-generation solar cells: thin-film solar cells; third-generation solar cells: novel solar cells, including dye-sensitized solar cells (DSSC), organic photovoltaic (OPV), quantum dot solar cells (QDSSC), and perovskite solar cells (PSC), etc.

[0004] Perovskite, as a direct bandgap material, can be used to prepare high-quality thin films with low volumetric defect density via solution methods. It possesses strong light absorption capabilities, exhibiting broad-spectrum absorption from the near-infrared to the entire visible region, long carrier diffusion length and lifetime, balanced bipolar charge transport with high electron-hole mobility, high luminous efficiency, and tunable bandgap. Furthermore, perovskite materials also display unique photoluminescence and electroluminescence properties. These outstanding characteristics have led to the widespread application of perovskite not only in photovoltaics but also in nanosensors, photodetectors, photocatalysis, photodetection, radiation detection, single-crystal devices, and light-emitting devices (LEDs, lasers, and EEPROMs). Utilizing different device structures and diverse perovskite absorber layers, various high-efficiency device fabrication processes have been achieved. Organic-inorganic hybrid perovskite solar cells have demonstrated tremendous appeal and broad development prospects, becoming a frontier in photovoltaic development.

[0005] Perovskite solar cells mainly consist of the following components: conductive substrate, electron transport layer, perovskite light-absorbing layer, hole transport layer, and metal electrode. The main problems hindering the industrialization of perovskite solar cells are as follows: (1) device stability; (2) perovskite preparation process; and (3) device hysteresis. Perovskite materials have poor humidity and thermal stability. Under high temperature and water vapor conditions, their structure will be damaged, leading to perovskite decomposition. The current improvement method is mainly to perform ion regulation in the ABX3 structure, introduce inorganic cation A, and improve the stability of perovskite materials. Another way to improve stability is to improve the device structure. The commonly used method is to add a layer of hydrophobic material between the perovskite layer and the air to avoid water molecules from contacting the perovskite layer as much as possible. Neither the regulation of components nor the improvement of structure can significantly improve the stability of perovskite devices. Often, efficiency is sacrificed as a means. Optimizing the perovskite active layer preparation process is another key issue in perovskite preparation. Although various preparation processes have been developed, they are still some distance from industrialization.

[0006] Relevant patent documents retrieved: This document, published in China (CN115161012A) on October 11, 2022, discloses a perovskite material, a thin film, and a solar cell device, as well as a method for their fabrication. The perovskite material used in this invention includes trihalomethylamine hydrohalide, an additive, and ABX3, with the additive being thiocyanate. The solar cell device fabricated using this invention achieves higher efficiency and exhibits better long-term operational stability. However, the trihalomethylamine hydrohalide used in this method is highly toxic, posing certain safety hazards in practical applications.

[0007] This document, published in China (CN119486564A) on February 18, 2025, discloses a perovskite precursor solution, a perovskite solar cell, and a method for its preparation. The perovskite precursor solution includes an organic solvent and an additive, which is a compound containing pyrrole and carboxyl groups. The carboxyl groups of the additive form an intermediate with the perovskite material, delaying film crystallization, improving the density and uniformity of the film, and enhancing film quality. Due to the strong coordination ability of the additive with perovskite, the solution has low fluidity during large-area coating, resulting in a longer time window and more uniform film growth. Furthermore, the pyrrole groups contain unsaturated nitrogen atoms, which can passivate free Pb within the perovskite, thus improving device performance. However, the perovskite precursor solution prepared using this method exhibits poor performance in subsequent solar cell fabrication, such as low open-circuit current and low photoelectric conversion efficiency.

[0008] Relevant non-patent literature retrieved: This master's thesis, titled "Improvement of Perovskite Thin Film Preparation Process and Research on its Battery Device Performance," published on May 30, 2018, discloses a method to improve the performance of perovskite solar cells. By introducing a certain amount of KSCN additive, the crystallinity of perovskite is improved, the grain size is increased, grain boundaries in the thin film are reduced, the light absorption intensity of the perovskite thin film is increased, defects are reduced, and electron-hole recombination is decreased. However, the photovoltaic performance of perovskite solar cells prepared using this method still needs further improvement.

[0009] There are still many problems to be solved in the perovskite film formation process, such as simplifying the preparation process, being environmentally friendly, and reducing energy consumption and costs. Therefore, it is urgent to further develop new processes and methods to prepare high-performance perovskite active layers. Summary of the Invention

[0010] The purpose of this invention is to provide: A composition for improving the performance of perovskite active layers and its application, as well as related technologies, to solve technical problems such as the poor humidity and thermal stability of perovskite materials, the destruction of their structure and decomposition of perovskite under high temperature and water vapor conditions, and the poor stability of the prepared perovskite films, or combinations thereof.

[0011] 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.

[0012] 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.

[0013] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0014] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0015] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the weights mentioned in the embodiments of this application can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0016] Unless otherwise stated, conventional methods within the scope of the art, such as photovoltaic performance testing and scanning electron microscopy, shall be used.

[0017] 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.

[0018] The terms “optional / arbitrary” or “optionally / arbitrarily” mean that the event or situation described below may or may not occur, including both the occurrence and non-occurrence of the event or situation.

[0019] 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.

[0020] 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 coating materials 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.

[0021] 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.

[0022] 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.

[0023] 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-ethyl)-phosphoric 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.

[0024] 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.

[0025] 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.

[0026] The term "hole transport layer" as 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, and is one of the key components affecting the performance of solar cells.

[0027] 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.

[0028] The term “film uniformity” as used in this article refers to the consistency of 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] As used in this article, the term "additive" refers to a small amount of substance added to improve the performance or properties of a material or product, or to meet the requirements of a specific processing technology.

[0035] The term "infrared wave furnace pre-annealing process" used in this article refers to the process of pre-annealing materials using an infrared wave furnace under certain process conditions. Annealing is a heat treatment process that aims to change the physical and / or chemical properties of materials through heating and cooling, thereby eliminating internal stress, improving microstructure, and enhancing material performance.

[0036] In a first aspect, the present invention provides: a composition for improving the performance of a perovskite active layer, comprising a perovskite material, a solvent, and an additive, wherein the perovskite material comprises cesium iodide (CsI), formamidinium iodide (FAI), lead bromide (PbBr2), and lead iodide (PbI2); The solvent is a mixture of N,N-dimethylformamide, N-methylpyrrolidone, and 1-ethyl-2-pyrrolidone; The additive is selected from one or more of NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, and CsOCN; The concentration of the perovskite material in the perovskite precursor solution is 1M; As a preferred embodiment, the mass percentage of the additive in the perovskite active layer is selected from any value or range between 1% and 10%. Preferably, the mass percentage of the additive in the perovskite active layer is selected from any value or range between 1 and 10%, specifically from: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of these ranges. More preferably, the mass percentage of the additive in the perovskite active layer is selected from any value or range between 1 and 10%, specifically from: 1%, 3%, 4%, 5%, 9%, 10% or any two of them. More preferably, the mass percentage of the additive in the perovskite active layer is selected from any value or range between 1 and 10%, specifically from: 1%, 4%, 8%, 10% or any two of them. More preferably, the additive has a mass percentage content of 4% in the perovskite active layer.

[0037] Preferably, the solvent is a mixture of N,N-dimethylformamide, 1-ethyl-2-pyrrolidone and N-methylpyrrolidone in a volume ratio of 8.4:0.6:1.

[0038] As a preferred embodiment, the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1-5:1-5. Preferably, the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1-5:1-5, specifically a mixture of potassium thiocyanate and rubidium thiocyanate in any value or range between 1:1, 1:2, 1:3, 1:4, 1:5, 2:1, 2:3, 2:4, and 2:5. More preferably, the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1-5:1-5, specifically a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1:1, 1:2, 1:3, 2:1, 2:3, 3:4, 4:5, 5:4. More preferably, the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1-5:1-5, specifically a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1:1, 1:3, 2:3, 3:4, 4:5, and 5:4. More preferably, the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1-5:1-5, specifically a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio selected from any value or range between 1:1, 1:3, 2:3, 4:5, and 5:4. More preferably, the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1:1.

[0039] In a second aspect, the present invention provides the application of the above composition in the preparation of flexible indoor photovoltaic modules.

[0040] Thirdly, the present invention provides: a flexible indoor photovoltaic module, the module comprising a perovskite active layer prepared by the above composition, a substrate, a conductive substrate, a hole transport layer, a self-assembled monolayer, an electron transport layer, and a metal top electrode.

[0041] Fourthly, the present invention provides a method for preparing the above-mentioned flexible indoor photovoltaic module, comprising the following steps: (1) Preparation of perovskite precursor solution: Dissolve the perovskite material in a solvent, filter, and obtain solution A; (2) Preparation of the composition: Add the additive to solution A, filter to obtain solution B, and set aside; (3) Preparation of perovskite active layer: The solution B prepared in step (1) is coated on the self-assembled monolayer film by slit coating method, and the perovskite active layer film is obtained after annealing.

[0042] Preferably, the annealing in step (3) is a two-step annealing method, wherein the first step is low-temperature pre-annealing and the second step is high-temperature annealing.

[0043] Preferably, the low-temperature pre-annealing is carried out in an infrared light wave furnace.

[0044] Preferably, the low-temperature pre-annealing temperature is 100°C and the time is 10 minutes.

[0045] Preferably, the high-temperature annealing is performed on a hot bench.

[0046] Preferably, the high-temperature annealing temperature is 150°C and the time is 20 minutes.

[0047] As the optimal implementation method, the preparation method includes the following steps: (1) Preparation of perovskite precursor solution: Dissolve the perovskite material in a solvent, wherein the solvent is a mixed solution of DMF, NMP and NEP with a mass ratio of 8.4:1:0.6, filter, and obtain solution A; (2) Preparation of composition: Add the additive to solution A, wherein the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1:1, filter to obtain solution B, and set aside for later use; (3) Preparation of perovskite active layer: The composition prepared in the slit coating step (1) is used to prepare a wide-bandgap perovskite active layer. The specific parameters are set as follows: coating speed 12mm / s, gap height 150um, liquid injection speed 28μL / s, VCD: 10s to 10Pa, 10Pa pressure held for 40s; immediately transfer to infrared light wave furnace for low-temperature pre-annealing. The pre-annealing temperature of the first stage is 100℃ and the pre-annealing time is 10min. In the second stage, the perovskite film is placed face down on the heating plate to ensure that the distance between the film and the heating plate is 5cm; then high-temperature annealing is performed at 150℃ for 20min to obtain the perovskite active layer film.

[0048] Based on further solutions to the technical problems of the present invention, or simultaneous solutions to multiple technical problems, the preferred solution in the technical solution provided in the first aspect of the present invention includes: The first preferred solution is a composition for improving the performance of perovskite active layers. This solution not only addresses the technical problem of "disordered grain formation" but also further solves the technical problems of "excessive moisture adsorption and poor stability".

[0049] Embodiments 1-13 of this invention at least support the protection scope of claim 1.

[0050] Regarding claim 1: the types of additives and their mass percentage content in the perovskite active layer. The technical feature “the additives are selected from one or more of NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, Pb(SCN)2 and CsOCN” is summarized by the common feature “additive composition” from the foregoing explanation and / or the corresponding technical features in Examples 1-13, which describe the additives as NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, Pb(SCN)2, CsOCN or combinations thereof. Therefore, those skilled in the art can reasonably presume that the technical feature "the additive is selected from one or more of NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, Pb(SCN)2 and CsOCN", its subordinate concepts and their essentially equivalent technical means, and technical means that can replace "the additive is selected from one or more of NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, Pb(SCN)2 and CsOCN" within the scope of conventional technical means and common knowledge based on the existing technical level, should all fall within the protection scope of claim 1. For example, if other technical features remain unchanged, replacing "the additive is selected from one or more of NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, Pb(SCN)2 and CsOCN" with a mixture of additives such as NH4SCN, KSCN, RbSCN and RbOCN, etc., still falls within the protection scope of claim 1 of this invention.

[0051] The technical feature "the mass percentage of the additive in the perovskite active layer is 1-10%" is derived from the common feature "the mass percentage of the additive in the perovskite active layer" in the foregoing explanation and / or Examples 1-13, where the mass percentage of the additive in the perovskite active layer is 1%, 4%, 5%, 8%, 10%, etc. Therefore, those skilled in the art can reasonably infer that the technical feature "the mass percentage of the additive in the perovskite active layer is 1-10%", its subordinate concepts and their substantially equivalent technical means, and technical means that can replace "the mass percentage of the additive in the perovskite active layer is 1-10%" based on existing technology and conventional technical means and common knowledge, should all fall within the protection scope of claim 1. For example, replacing "the mass percentage of the additive in the perovskite active layer is 1-10%" with "the mass percentage of the additive in the perovskite active layer is 3.5%" while other technical features remain unchanged still falls within the protection scope of claim 1 of this invention.

[0052] Embodiments 1-13 of this invention at least support the protection scope of claim 4.

[0053] Regarding the mass percentage of the additive in the perovskite active layer as described in claim 1: The technical feature “the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1-5:1-5” is derived from the aforementioned explanation and / or the corresponding technical feature in Examples 1-13, where the additive is potassium thiocyanate and rubidium thiocyanate, and the mass ratio of potassium thiocyanate to rubidium thiocyanate is 1:1, 1:3, 2:3, 4:5, 5:4, etc., summarized from the common feature “additive combination and its ratio”. Therefore, those skilled in the art can reasonably presume that the technical feature "the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1-5:1-5", its subordinate concepts and their essentially equivalent technical means, and technical means that can replace "the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1-5:1-5" based on existing technology and conventional technical means and common knowledge, should all fall within the protection scope of claim 4. For example, if other technical features remain unchanged, replacing "the additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1-5:1-5" with an additive being a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 3.5:1.5 still falls within the protection scope of claim 4 of this invention.

[0054] The present invention has at least the following beneficial effects: 1. This invention adds a specific combination and content of additives to the perovskite precursor solution to regulate vertical growth, reduce grain boundaries, and optimize preferred orientation.

[0055] 2. The SCN- in the additive occupies the I- vacancy, blocking the water adsorption site, and can form a hydrophobic barrier during pre-annealing at 80-120℃, allowing for long-term diffusion of Br / I ions with rapid heating, thus greatly reducing the risk of phase separation.

[0056] 3. The perovskite active layer prepared by this invention can achieve delayed crystallization and phase segregation suppression, thereby significantly improving the performance and stability of indoor low-light photovoltaic modules.

[0057] Furthermore, based on the present invention: 1. Based on the comparison of Examples 9-13 and Comparative Examples 4-6, the present invention purposefully selects narrow-range KSCN and RbSCN and their specific ratios not mentioned in the prior art from the wide range of battery additives disclosed in the prior art, which significantly improves the performance of the prepared solar cells and achieves unexpected technical effects. Attached Figure Description

[0058] Figure 1 The morphology of the perovskite activation layer prepared in Example 9. Detailed Implementation

[0059] 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.

[0060] 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.

[0061] Table 1

[0062] Examples 1-8: Preparation of Perovskite Precursor Solutions Table 2 Composition and content of perovskite precursor solution

[0063] Preparation method: (1) Dissolve the indoor weak light perovskite precursor solution composed of CsI, FAI, PbI2 and PbBr2 in a mixed solvent of DMF, NEP and NMP, wherein the solvent is a mixed solution of DMF, NEP and NMP with a mass ratio of 8.4:0.6:1. Filter to obtain solution A for later use. (2) Preparation of composition: Add additive to solution A, filter to obtain solution B, and then obtain the composition.

[0064] Examples 9-13: Preparation of Perovskite Precursor Solutions Table 3 Composition and content of perovskite precursor solution

[0065] Preparation method: (1) Dissolve the indoor weak light perovskite precursor solution composed of CsI, FAI, PbI2 and PbBr2 in a mixed solvent of DMF, NMP and NEP, wherein the solvent is a mixed solution of DMF, NEP and NMP with a mass ratio of 8.4:0.6:1. Filter to obtain solution A for later use. (2) Preparation of composition: Add additive to solution A, filter to obtain solution B, and then obtain the composition.

[0066] Comparative Example 1 The difference from Example 9 is that the combination of additives is different; the additives are KSCN, RbSCN and KCl in a mass ratio of 1:1:1.

[0067] The remaining steps are the same as in Example 9.

[0068] Comparative Example 2 The difference from Example 9 is that the content of the additive is different; the mass percentage of the additive is 0.8%, while the remaining steps are the same as in Example 9.

[0069] Comparative Example 3 The difference from Example 9 is that the content of the additive is different; the mass percentage of the additive is 11%, while the remaining steps are the same as in Example 9.

[0070] Comparative Examples 4-6 The difference from Example 9 lies in the different mass percentage content, combination, and proportion of the additives, specifically: Table 4 Composition and content of perovskite precursor solution

[0071] Application Example 1: Fabrication of Flexible Perovskite Solar Cells (1) Substrate preparation: P1 etching was performed on a flexible ITO substrate using a red nanosecond laser to separate multiple sub-cells from the bottom, resulting in PET; (2) Preparation of conductive substrate: After P1 is scratched in PET / ITO, the conductive substrate is obtained by spray cleaning → brush cleaning → ultrasonic cleaning → two-fluid cleaning → spray cleaning → air knife drying. (3) Preparation of NiOx hole transport layer by magnetron sputtering: The cleaned flexible substrate was placed in a magnetron sputtering device with a sputtering power of 2000W, an argon flow rate of 400sccm, an oxygen flow rate of 2sccm, and sputtered at room temperature for 3 cycles to obtain a 20nm thick NiOx hole transport layer. (4) Preparation of self-assembled monolayer: The self-assembled monolayer is a Me-4PACz solution with a concentration of 0.5 mg / mL and ethanol as the solvent. The Me-4PACz solution is deposited on the NiOx transport layer by slit coating at a coating speed of 5 mm / s, a liquid injection speed of 8 μL / s, and a gap of 100 μm. The self-assembled monolayer film is obtained by annealing at 100 °C for 10 min. (5) Preparation of perovskite active layer: Wide-bandgap perovskite active layer was prepared using the composition prepared in Example 1 with slit coating. The specific parameters were set as follows: coating speed 12 mm / s, gap height 150 μm, liquid injection speed 28 μL / s, VCD: pumped to 10 Pa in 10 s, and held at 10 Pa for 40 s. The perovskite film was immediately transferred to an infrared light wave furnace for low-temperature pre-annealing. The first stage of low-temperature pre-annealing was at 100 °C for 10 min. The second stage was high-temperature annealing. The perovskite film was placed face down on the heating plate, ensuring that the distance between the film and the heating plate was 5 cm. Then, high-temperature annealing was performed at 150 °C for 20 min to obtain the perovskite active layer film. (6) Preparation of electron transport layer: deposition of C 60 A 15nm C layer was deposited on the surface of the perovskite active layer using a thermal evaporation method. 60 (fullbody); (7) Preparation of hole transport layer: 25 nm SnO was deposited on the C60 surface using ALD in-situ atomic deposition. x ; (8) Preparation of metal electrodes (8.1) P2 etching: P2 etching 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 serves as the interconnection region between the metal top electrode and the flexible ITO bottom electrode. (8.2) Copper electrode deposition: The copper electrode is deposited on SnO after P2 is applied using a thermal evaporation method. x 150nm copper electrode was deposited on the surface; (8.3) P3 etching: P3 etching is performed using a green picosecond laser to cut off the P3 metal region and separate multiple sub-cells from the top to obtain a flexible perovskite solar cell module.

[0072] Application Example 2: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 2, and the remaining steps were the same as in Application Example 1.

[0073] Application Example 3: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 3, and the remaining steps were the same as in Application Example 1.

[0074] Application Example 4: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 4, and the remaining steps were the same as in Application Example 1.

[0075] Application Example 5: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 5, and the remaining steps were the same as in Application Example 1.

[0076] Application Example 6: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 6, and the remaining steps were the same as in Application Example 1.

[0077] Application Example 7: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 7, and the remaining steps were the same as in Application Example 1.

[0078] Application Example 8: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 8, and the remaining steps were the same as in Application Example 1.

[0079] Application Example 9: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 9, and the remaining steps were the same as in Application Example 1.

[0080] Application Example 10: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 10, and the remaining steps were the same as in Application Example 1.

[0081] Application Example 11: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared by slit coating of the composition prepared in Example 11, and the remaining steps were the same as in Application Example 1.

[0082] Application Example 12: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 12, and the remaining steps were the same as in Application Example 1.

[0083] Application Example 13: Fabrication of Flexible Perovskite Solar Cells The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared using the composition prepared in Slit Coating Example 13, and the remaining steps were the same as in Application Example 1.

[0084] Application Comparative Example 1 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared by slit coating of the composition prepared in Comparative Example 1. The remaining steps were the same as in Application Example 1.

[0085] Application Comparative Example 2 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: The wide-bandgap perovskite active layer was prepared by slit coating of the composition prepared in Comparative Example 2. The remaining steps were the same as in Application Example 1.

[0086] Application Comparative Example 3 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: Wide-bandgap perovskite active layer is prepared by slit coating of the composition prepared in Comparative Example 3. The remaining steps are the same as in Application Example 1.

[0087] Application Comparative Example 4 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: Wide-bandgap perovskite active layer is prepared by slit coating of the composition prepared in Comparative Example 4. The remaining steps are the same as in Application Example 1.

[0088] Application Comparative Example 5 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: Wide-bandgap perovskite active layer is prepared by slit coating of the composition prepared in Comparative Example 5. The remaining steps are the same as in Application Example 1.

[0089] Application Comparative Example 6 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: Wide-bandgap perovskite active layer is prepared by slit coating with perovskite precursor solution prepared in Comparative Example 6. The remaining steps are the same as in Application Example 1.

[0090] Application Comparative Example 7 The perovskite active layer preparation differs from that in Application Example 1, specifically as follows: (5) Preparation of perovskite active layer: Wide-bandgap perovskite active layer was prepared by slit coating with the perovskite precursor solution prepared in Example 9. The specific parameters were set as follows: coating speed 12 mm / s, gap height 150 μm, injection speed 28 μL / s, VCD: pumped to 10 Pa in 10 s, and held at 10 Pa for 40 s. The perovskite film was immediately transferred to a tunnel furnace for low-temperature pre-annealing. The pre-annealing temperature in the first stage was 100 °C and the pre-annealing time was 10 min. In the second stage, the perovskite film was placed face down on the heating plate, ensuring that the distance between the film and the heating plate was 5 cm. Then, high-temperature annealing was performed at 150 °C for 20 min to obtain the perovskite active layer film. The remaining steps are the same as in Application Example 1.

[0091] Test Example 1: Photovoltaic Performance Testing of Flexible Perovskite Solar Cells 1. Testing method: The components prepared using Examples 1-13 and Comparative Examples 1-7 had a size of 10 × 10 cm. 2 The aperture area is 88.47 cm². 2 The device's performance was tested by simulating low indoor light illumination under LED conditions of 3000K and 200lux. The performance parameters included photoelectric conversion efficiency (Eff), open-circuit voltage (Voc), short-circuit current (Isc), and fill factor (FF). The obtained photovoltaic performance parameters are shown in Table 5.

[0092] 2. Test Results As shown in Table 5, different concentrations and combinations of additives have a significant impact on battery performance. Even with the same amount of additives, different combinations of additives have a substantial effect on the open-circuit voltage, fill factor, and photoelectric conversion efficiency of flexible perovskite solar cells. This may be due to the synergistic effect between specific combinations of additives, solvents, and preparation processes.

[0093] In summary, this invention prepares a perovskite activation layer through the synergistic effect of specific additive combinations and their ratios, solvent combinations, and preparation processes. This layer is then used in the subsequent fabrication of flexible perovskite solar cells, which can effectively improve the photovoltaic performance of flexible perovskite solar cells in indoor low-light environments, and has significant application value.

[0094] Table 5. Photovoltaic performance test results of flexible perovskite solar cells

[0095] 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 composition for improving the performance of a perovskite active layer, characterized in that, It includes perovskite materials, solvents, and additives, wherein the perovskite materials include cesium iodide, formamidinium iodide, lead bromide, and lead iodide; The solvent is a mixture of N,N-dimethylformamide, N-methylpyrrolidone, and 1-ethyl-2-pyrrolidone; The additive is selected from one or more of NH4SCN, KSCN, RbSCN, RbOCN, CsSCN, GASCN, and CsOCN; The concentration of the perovskite material in the perovskite precursor solution is 1M; The additive has a mass percentage content of 1-10% in the perovskite active layer.

2. The composition according to claim 1, characterized in that, The solvent is a mixture of N,N-dimethylformamide, 1-ethyl-2-pyrrolidone and N-methylpyrrolidone in a volume ratio of 8.4:0.6:

1.

3. The composition according to claim 1, characterized in that, The additive has a mass percentage of 4% in the perovskite active layer.

4. The composition according to claim 1, characterized in that, The additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1-5:1-5.

5. The composition according to claim 4, characterized in that, The additive is a mixture of potassium thiocyanate and rubidium thiocyanate in a mass ratio of 1:

1.

6. The use of the composition according to any one of claims 1-5 in the preparation of flexible indoor photovoltaic modules.

7. A flexible indoor photovoltaic module, characterized in that, The components include a perovskite active layer, a substrate, a conductive substrate, a hole transport layer, a self-assembled monolayer, an electron transport layer, and a metal top electrode, all prepared from the compositions of any one of claims 1-5.

8. The method for preparing the flexible indoor photovoltaic module according to claim 7, characterized in that, The preparation of the perovskite active layer includes the following steps: (1) Preparation of perovskite precursor solution: Dissolve the perovskite material in a solvent, filter, and obtain solution A; (2) Preparation of the composition: Add the additive to solution A, filter to obtain solution B, and set aside; (3) Preparation of perovskite active layer: The solution B prepared in step (1) is coated on the self-assembled monolayer film by slit coating method, and the perovskite active layer film is obtained after annealing.

9. The preparation method according to claim 8, characterized in that, The annealing described in step (3) is a two-step annealing method. The first step is low-temperature pre-annealing, and the second step is high-temperature annealing.

10. The preparation method according to claim 9, characterized in that, The low-temperature pre-annealing is carried out in an infrared light wave furnace.

11. The preparation method according to claim 9, characterized in that, The high-temperature annealing is carried out on a hot bench.

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