A method and device for preparing perovskite thin film and solar cell

Abstract

The invention discloses a method, equipment and solar cell for preparing a perovskite film, belonging to the technical field of semiconductor devices. The preparation method comprises: using metal halide PbCl2 as a first deposition source material and methylammonium iodide MAI as a second deposition source material; setting a target thickness of the perovskite film to be prepared; determining optimal preparation parameters under various target thicknesses with the goal of improving the photovoltaic performance, uniformity and fatigue strength of the perovskite film; cleaning a substrate and mounting it on a substrate fixing table; heating the substrate; first heating the first deposition source material; then heating the second deposition source material, controlling the sedimentation process to maintain at the optimal preparation parameters; when the first deposition source material and the second deposition source material meet on the substrate, forming a perovskite film through a chemical reaction; when the perovskite film on the substrate reaches the target thickness, immediately stopping heating; and annealing the perovskite film.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a method and equipment for preparing a perovskite film and a solar cell. Background Art

[0002] Perovskite thin film is a thin film based on perovskite structural materials, which has shown great potential in the photovoltaic field (especially solar cells) in recent years. Due to its excellent photoelectric properties, perovskite materials are widely used in photovoltaic devices.

[0003] Perovskite films can be prepared by deposition technology, and common deposition methods include spin coating and spray deposition.

[0004] However, the spin coating method is easily affected by factors such as solution concentration, spin coating speed, and environmental conditions, resulting in poor uniformity of film thickness and composition, especially when preparing large areas.

[0005] The spray deposition method is easily affected by factors such as spray particle size, spray direction and speed, which will also lead to poor film thickness and uniformity. This problem is more prominent when preparing large areas. Summary of the invention

[0006] In order to solve the technical problems that the traditional spin coating method is easily affected by factors such as solution concentration, spin coating speed, environmental conditions, etc., and the spray deposition method is easily affected by factors such as spray particle size, spray direction and speed, resulting in poor uniformity of film thickness and composition, which is more obvious in large-area preparation, the present invention provides a perovskite film preparation method, equipment and solar cell.

[0007] A first aspect of the present invention provides a method for preparing a perovskite film, comprising:

[0008] S1: using metal halide PbCl2 as the first deposition source material and methylammonium iodide MAI as the second deposition source material;

[0009] S2: setting the target thickness of the perovskite film to be prepared;

[0010] S3: To improve the photovoltaic performance, uniformity and fatigue strength of the perovskite film, determine the optimal preparation parameters at various target thicknesses;

[0011] S4: cleaning the substrate and mounting it on the substrate fixing table;

[0012] S5: heating the substrate;

[0013] S6: first heating the first deposition source material, and monitoring the deposition rate of the first deposition source material through a first sensor;

[0014] S7: subsequently heating the second deposition source material, and monitoring the deposition rate of the second deposition source material by a second sensor, and during the heating process, controlling the sedimentation process to maintain at the optimal preparation parameters;

[0015] S8: when the first deposition source material and the second deposition source material meet on the substrate, a perovskite film is formed through a chemical reaction;

[0016] S9: when the perovskite film on the substrate reaches the target thickness, immediately stop heating the first deposition source material and the second deposition source material;

[0017] S10: performing annealing treatment on the perovskite film.

[0018] The second aspect of the present invention provides a perovskite film preparation device, which is used to implement the perovskite film preparation method described in the first aspect, and the perovskite film preparation device includes: a housing, a substrate fixing table, a substrate, a substrate shielding plate, a first crucible, a first heating wire, a first sensor, a second crucible, a second heating wire, a second sensor, an exhaust system and an intelligent controller;

[0019] A vacuum accommodating space is provided inside the shell;

[0020] The substrate fixing platform, the substrate, the substrate shielding plate, the first crucible, the first heating wire, the first sensor, the second crucible, the second heating wire, the second sensor and the intelligent controller are arranged in the accommodating space;

[0021] The substrate fixing platform is fixedly connected to the top surface of the shell;

[0022] The substrate is arranged on the substrate fixing platform;

[0023] The substrate shielding plate is disposed below the substrate fixing platform, and the substrate shielding plate is used to prevent the deposition source material from being directly deposited on the substrate after being heated;

[0024] The first crucible is provided with the first heating wire, and the first deposition source material in the first crucible is heated and evaporated by the first heating wire;

[0025] The first sensor is used to monitor the deposition rate of the first deposition source material;

[0026] The second crucible is provided with the second heating wire, and the second deposition source material in the second crucible is heated and evaporated by the second heating wire;

[0027] The second sensor is used to monitor the deposition rate of the second deposition source material;

[0028] The exhaust system is connected to the interior of the housing through a pipeline, and the exhaust system is used to accurately control the deposition rate of the second deposition source material;

[0029] The intelligent controller is connected to the first heating wire, the second heating wire and the air extraction system.

[0030] A third aspect of the present invention provides a solar cell provided with a perovskite thin film prepared by the perovskite thin film preparation method described in the first aspect.

[0031] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0032] (1) In the present invention, metal halide PbCl2 is used as the first deposition source material and methylammonium iodide MAI is used as the second deposition source material to carry out mixed vacuum evaporation deposition to prepare the perovskite film. Under a vacuum environment, the evaporation rates of PbCl2 and MAI can be very accurately controlled by heating the evaporation source, thereby improving the uniformity of the film thickness and facilitating large-area preparation.

[0033] (2) In the present invention, the photovoltaic performance, uniformity and fatigue strength of the perovskite film are improved, the optimal preparation parameters at various target thicknesses are determined, and during the heating process, the sedimentation process is controlled to remain at the optimal preparation parameters. This can accurately control the deposition process, ensure the stability and consistency of the deposition process, help to make the thickness of the film uniform, reduce local differences in thickness and composition, and thus improve the overall uniformity, photovoltaic performance and fatigue strength of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0035] Figure 1 It is a schematic flow chart of a method for preparing a perovskite film provided by the present invention.

[0036] Figure 2 It is a structural schematic diagram of a perovskite film preparation system provided by the present invention.

[0037] [Reference Signs]

[0038] 1. Shell; 2. Substrate fixing table; 3. Substrate; 4. Substrate shielding plate; 5. First crucible; 6. First heating wire; 7. First sensor; 8. Second crucible; 9. Second heating wire; 10. Second sensor; 11. Exhaust system; 12. Intelligent controller; 13. Partition; 14. Third crucible; 15. Third heating wire; 16. Third sensor. DETAILED DESCRIPTION

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0040] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0041] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0042] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In addition, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0044] Example 1

[0045] In one embodiment, the reference specification Figure 1 , showing a schematic flow chart of a method for preparing a perovskite film provided by the present invention.

[0046] The present invention provides a method for preparing a perovskite film, comprising:

[0047] S1: using metal halide PbCl2 as a first deposition source material and using methylammonium iodide MAI as a second deposition source material.

[0048] Among them, PbCl2 (lead chloride) is an inorganic compound, usually white or colorless crystals. When heated, PbCl2 can sublimate to form gaseous lead chloride, which makes it suitable for vacuum evaporation deposition process. MAI (methylammonium iodide) is an organic compound with the chemical formula CH3NH3I. In the preparation of perovskite solar cells, MAI is the source of organic cations that form the perovskite structure. MAI reacts with PbCl2 to form perovskite material (CH3NH3PbI3).

[0049] S2: Setting the target thickness of the perovskite film to be prepared.

[0050] Among them, those skilled in the art can set the target thickness according to actual conditions, and the present invention does not limit it, for example, 100 nm, 200 nm, 300 nm, etc.

[0051] It should be noted that perovskite films of different thicknesses require different preparation parameters.

[0052] S3: Determine the optimal preparation parameters at various target thicknesses with the goal of improving the photovoltaic performance, uniformity, and fatigue strength of perovskite films.

[0053] Optionally, the preparation parameters include: a deposition rate ratio of the first deposition source material to the second deposition source material, a substrate temperature, and an annealing temperature.

[0054] In a possible implementation, S3 specifically includes sub-steps S301 and S302:

[0055] S301: Construct an objective function with the goal of improving the photovoltaic performance, uniformity, and fatigue strength of perovskite films.

[0056] Optionally, the objective function is specifically:

[0057]

[0058] in, f represents the objective function, b 1 represents photovoltaic performance parameters, b 2 represents the uniformity parameter, b 3 represents fatigue strength parameter, β 1 represents the weight coefficient of photovoltaic performance parameters, β 2 represents the weight coefficient of the uniformity parameter, β 3 represents the weight coefficient of fatigue strength parameter.

[0059] Among them, those skilled in the art can set the weight coefficient of photovoltaic performance parameters according to actual conditions. β 1. Weight coefficient of uniformity parameter β 2 and the weight coefficient of fatigue strength parameters β The size of 3 is not limited in the present invention.

[0060] In practical applications, there may be some contradiction or competition between photovoltaic performance, uniformity and fatigue strength. Through the objective function, the weight of each performance index can be flexibly adjusted according to the needs of specific applications to find an optimal balance point and improve the overall performance of the film.

[0061] Optionally, the photovoltaic performance parameters are specifically:

[0062]

[0063] in, J 0 represents the reverse saturation current density, B represents the ideality factor, t ir represents the instantaneous relaxation time, PCE represents the photoelectric conversion efficiency, FF represents the filling factor, m 1 represents the weight coefficient of reverse saturation current density, m 2 represents the weight coefficient of the ideal factor, m 3 represents the weight coefficient of instantaneous relaxation time, m 4 represents the weight coefficient of photoelectric conversion efficiency, m 5 represents the weight coefficient of the fill factor.

[0064] Among them, those skilled in the art can set the weight coefficient of the reverse saturation current density according to actual conditions. m 1. Weight coefficient of ideal factor m 2. Weight coefficient of instantaneous relaxation time m 3. Weight coefficient of filling factor m 4, and the weight coefficient of photoelectric conversion efficiency m The size of 5 is not limited in the present invention.

[0065] Among them, the reverse saturation current density J 0 is a key parameter of the diode, which represents the minority carrier current density under reverse bias. It is the current caused by the diffusion of minority carriers generated by thermal excitation in the PN junction. Reverse saturation current density J The lower the 0, the less the minority carrier recombination in the device, thus reducing the loss of photocurrent. JThe higher the 0, the larger the dark current loss will be, which will reduce the open circuit voltage and the photoelectric conversion efficiency (PCE), thus reducing the overall efficiency of the solar cell.

[0066] Among them, the ideal factor B A measure of how much the current-voltage characteristics of a photovoltaic device deviate from the ideal diode model. The ideality factor reflects the recombination mechanisms in the device and is usually between 1 and 2. Ideality Factor B A value equal to 1 indicates that the carriers in the device mainly recombine through radiation, which is an ideal recombination method and helps to improve device efficiency. B A value greater than 1 implies the presence of other recombination mechanisms, such as Shockley-Read-Hall (SRH) recombination or interfacial recombination, which can lead to current loss and thus reduce the open circuit voltage and fill factor ( FF ).

[0067] Among them, the instantaneous relaxation time t ir It refers to the time required for photogenerated carriers to return from the excited state to the ground state in semiconductor materials. t ir A longer time means a longer lifetime of photogenerated carriers, and carriers have more time to be collected before recombination, thereby increasing the short-circuit current density and improving the overall conversion efficiency (PCE). t ir A shorter distance indicates rapid recombination of carriers, which reduces the number of carriers that can be collected, thereby reducing the short-circuit current density and photovoltaic performance.

[0068] Among them, the photoelectric conversion efficiency PCE It is a comprehensive indicator to measure the performance of solar cells, indicating the efficiency of converting incident light energy into electrical energy.

[0069] Among them, the filling factor FF It is an important performance parameter of photovoltaic devices, the fill factor FF Directly affects the maximum power output of solar cells. FF The higher it is, the closer the device's voltage and current curves are to an ideal rectangular shape, meaning the battery's energy conversion efficiency is higher.

[0070] Furthermore, the perovskite film can be designed into a photovoltaic solar cell to measure the photoelectric conversion efficiency. PCE Fill Factor FF .

[0071] In the present invention, multiple key factors affecting photovoltaic performance (such as reverse saturation current density, ideality factor, instantaneous relaxation time, fill factor, and photoelectric conversion efficiency) are incorporated into the evaluation system. This comprehensive consideration approach can more comprehensively evaluate the performance of photovoltaic devices, rather than focusing on a single indicator.

[0072] Optionally, the reverse saturation current density and the ideality factor are determined as follows:

[0073]

[0074] in, V Indicates voltage, J represents the current density, d represents the differential operation, A represents the ideality factor, K B represents the Boltzmann constant, T represents absolute temperature, J SC is the short-circuit current density, q e represents the charge of an electron, R S represents the series resistance, ln represents the natural constant e The logarithmic function with base , J0 represents the reverse saturation current density, V OC Indicates the open circuit voltage.

[0075] Optionally, the instantaneous relaxation time is calculated as follows:

[0076]

[0077] in, t ir represents the instantaneous relaxation time, V OC Indicates the open circuit voltage.

[0078] Optionally, the uniformity parameter is specifically:

[0079]

[0080] in, RMS d represents the thickness standard deviation, RMS X represents the standard deviation of X-ray diffraction peak intensity, or 1 represents the weight coefficient of thickness standard deviation, or 2 represents the weight coefficient of the standard deviation of X-ray diffraction peak intensity.

[0081] Among them, those skilled in the art can set the weight coefficient of the thickness standard deviation according to the actual situation. or 1 and the weight coefficient of the standard deviation of the X-ray diffraction peak intensity or The size of 2 is not limited in the present invention.

[0082] In the present invention, the formula takes into account both the thickness uniformity and crystal structure uniformity of the film. Thickness uniformity reflects the thickness variation of the film at different locations, while crystal structure uniformity reflects the consistency of crystal quality through the variation of X-ray diffraction peak intensity. By combining these two indicators, the overall uniformity of the film can be comprehensively evaluated.

[0083] Optionally, the thickness standard deviation is calculated as follows:

[0084]

[0085] in, d i Indicates i The thickness at each measuring point, represents the average thickness, N Indicates the total number of measurement points.

[0086] Optionally, the calculation method of the standard deviation of the X-ray diffraction peak intensity is specifically as follows:

[0087]

[0088] in, X i Indicates i The X-ray diffraction peak intensity at each measurement point, represents the average value of X-ray diffraction peak intensity, N Indicates the total number of measurement points.

[0089] Optionally, the fatigue strength parameter is specifically:

[0090]

[0091] in, s max represents the maximum stress, N f represents the number of failure cycles, b Represents the material fatigue index.

[0092] S302: Determine the optimal preparation parameters at various target thicknesses by using a particle swarm optimization algorithm with the goal of maximizing the objective function.

[0093] Among them, Particle Swarm Optimization (PSO) is a global optimization algorithm based on swarm intelligence. It simulates the behavior of bird flocks foraging or fish schools swimming, and searches for the global optimal solution in the search space through cooperation and competition between individuals.

[0094] Specifically, the objective function is the fitness function of the particle swarm optimization algorithm.

[0095] Initial particle group, the particle group contains multiple particles, each particle represents a preparation parameter combination.

[0096] Calculate the fitness value of each particle.

[0097] The position of the particle with the highest fitness value is determined as the global optimal position.

[0098] The position of each particle is updated according to the following formula:

[0099]

[0100] in, Indicates i The particle in t The particle position at iteration +1, Indicates i The particle in t The displacement vector at the iteration, exp represents the exponential function with the natural constant as the base, s Represents the shape parameter, which is a random number between -1 and 1. r represents the logarithmic spiral constant, P best represents the global optimal position, d represents the attraction factor, Indicates t The global optimal position at the iteration.

[0101] In the present invention, the particles are guided to move along the spiral trajectory through the spiral mechanism, so that the particles can perform more diverse explorations in the search space, thus preventing the particle swarm from falling into the local optimal solution, thereby improving the global search capability.

[0102] In the present invention, the attraction factor is used to enhance the attraction of particles to the global optimal position, which promotes the particles to quickly approach the optimal solution, thereby accelerating convergence. This is especially important in the later stage of the algorithm because it can help search for areas near the optimal solution in the particle cluster and avoid excessively long convergence time.

[0103] The displacement vector is specifically:

[0104]

[0105] Where MMI represents mutual information, sim Represents the Euclidean distance similarity.

[0106] In the present invention, by using the Euclidean distance, when the similarity is low, the particles tend to move directly toward the global optimal position, enhancing global convergence; when the similarity is high, the particles will make adjustments based on mutual information, thereby retaining some exploration behavior. This adaptive adjustment mechanism can flexibly adjust the movement direction of the particle according to its current position and search state, avoid falling into the local optimal solution too early, and perform a detailed search when approaching the optimal solution.

[0107] The mutual information is specifically:

[0108]

[0109] in, H represents information entropy, Indicates i The particle in t The information entropy of the particle position at the iteration, Indicates t The information entropy of the global optimal position at the iteration is Indicates i The particle in t The joint information entropy with the global optimal position at the iteration.

[0110] In the present invention, the introduction of mutual information (MMI) makes the movement of particles no longer rely solely on position differences, but also considers the statistical information correlation between positions. Mutual information helps particles decide how to adjust their positions by calculating the correlation between the particle position and the global optimal position. High mutual information means that there is more information sharing between the two positions, which means that the two positions may have similar structures or patterns. In this case, particles can perform local exploration by retaining more independence.

[0111] Determine whether the maximum number of iterations has been reached. If so, output the preparation parameters represented by the particle with the highest fitness value as the optimal preparation parameters; otherwise, return to continue iterating.

[0112] In the present invention, by constructing an objective function and using a particle swarm optimization algorithm to determine the optimal preparation parameters of the perovskite film, not only can the optimal solution be quickly found in the multidimensional parameter space to improve the comprehensive performance of the film, but also the stability and repeatability of the process can be improved to meet the needs of different thicknesses and application scenarios. The automation and intelligent characteristics of this method significantly reduce production costs, improve production efficiency, and make the production of perovskite films more competitive.

[0113] S4: Clean the substrate and install it on the substrate fixing table.

[0114] In a possible implementation, the substrate is cleaned in S4, specifically, the FTO coated glass substrate is etched using zinc powder and hydrochloric acid, ultrasonically cleaned using soap, deionized water, ethanol and isopropanol in sequence, and blown dry with nitrogen.

[0115] In the present invention, the ultrasonic cleaning process using soap, deionized water, ethanol and isopropanol can effectively remove grease, dust and other organic contaminants on the substrate surface, thereby ensuring that the substrate surface is clean and free of contamination, thereby avoiding the introduction of defects in the subsequent thin film deposition process.

[0116] S5: heating the substrate.

[0117] Optionally, the substrate is heated to an optimal substrate temperature determined from the optimal preparation parameters.

[0118] It should be noted that the substrate temperature plays a vital role in the preparation process of perovskite films. It directly affects the crystallization quality, morphology, optoelectronic properties and uniformity of the film. Appropriate substrate temperature helps the grain growth of perovskite materials. Appropriate substrate temperature can provide enough kinetic energy for atoms or molecules to enable them to move to more stable lattice positions on the substrate surface, thereby forming larger grains. The larger the grains, the fewer grain boundaries, and the less scattering of carriers when diffusing in the film, which helps to improve the optoelectronic properties of the film.

[0119] S6: first heating the first deposition source material, and monitoring the deposition rate of the first deposition source material through a first sensor.

[0120] S7: Then, the second deposition source material is heated, and the deposition rate of the second deposition source material is monitored by a second sensor. During the heating process, the sedimentation process is controlled to be maintained at the optimal preparation parameters.

[0121] In a possible implementation, the sedimentation process in S7 is controlled to be maintained at the optimal preparation parameters, specifically: the sedimentation process is controlled to be maintained at the optimal preparation parameters through an intelligent agent based on deep reinforcement learning.

[0122] Among them, Deep Reinforcement Learning (DRL) is an intelligent agent method that combines reinforcement learning and deep learning. It uses deep neural networks (DNNs) to approximate value functions or policies to make decisions in complex, high-dimensional environments.

[0123] In one possible implementation, controlling the sedimentation process in S7 to maintain optimal preparation parameters specifically includes:

[0124] S701: Constructing the environment space of the intelligent agent:

[0125]

[0126] in, s Indicates the environment, s 1 represents the deposition rate of the first deposition source material, s 2 represents the deposition rate of the second deposition source material, s 3 represents the deposition rate ratio between the first deposition source material and the second deposition source material.

[0127] S702: Construct the action space of the intelligent agent:

[0128]

[0129] in, a Indicates action, a 1 indicates adjusting the heating power of the first heating wire, which is used to heat and evaporate the first deposition source material. a 2 indicates adjusting the heating power of the second heating wire, which is used to heat and evaporate the second deposition source material. a 3 indicates adjusting the power of the exhaust system, where the exhaust system is used to control the deposition rate of the second deposition source material.

[0130] S703: Construct a reward function for the agent. The reward function is used to provide rewards or penalties for the agent according to the results of the action execution. The specific reward function is:

[0131]

[0132] in, r represents the reward function, r 1 represents the energy consumption reward function, r 2 represents the deposition rate proportional reward function, l 1 represents the weight coefficient of the energy consumption reward function, l 2 represents the weight coefficient of the deposition rate proportional reward function.

[0133] Among them, technicians in this field can set the weight coefficient of the energy consumption reward function according to actual conditions. l 1 and the weight coefficient of the deposition rate proportional reward function l The size of 2 is not limited in the present invention.

[0134] In the present invention, the reward function helps the intelligent agent maintain the optimal energy consumption and rate ratio during the deposition process, significantly improving production efficiency, product quality and energy utilization, making process control more efficient and intelligent.

[0135] The energy consumption reward function is as follows:

[0136]

[0137] in, P 1 represents the heating power of the first heating wire, P 2 represents the heating power of the second heating wire, P 3 represents the power of the exhaust system.

[0138] It should be noted that through the energy consumption reward function, the digital agent can reduce the energy used in the deposition process, which helps to reduce production costs and reduce environmental impact, especially in large-scale industrial production.

[0139] The specific deposition rate proportional reward function is:

[0140]

[0141] in, R represents the actual deposition rate ratio of the first deposition source material to the second deposition source material, R f It represents the optimal deposition rate ratio of the first deposition source material to the second deposition source material.

[0142] It should be noted that the deposition rate proportional reward function ensures that the proportion of materials in the deposition process is as close to the optimal value as possible, which helps to ensure the composition uniformity of the film and the quality of the final product.

[0143] S704: In the online network, use e -greedy strategy in the environment s t Next select an action a t , s t Indicates t The environment at the time of the iteration, a t Indicates t The action to be chosen at iteration .

[0144] in, e -greedy strategy is an action selection strategy commonly used in reinforcement learning to balance the relationship between exploration and exploitation. eExplore and randomly select a new action with probability 1- e Choose the best action known so far.

[0145] S705: Execute action a t , get reward r t , r t Indicates t The reward obtained at the iteration.

[0146] S706: When this As t The parameters at that moment are stored in the experience pool.

[0147] S707: Introduction Q Function, calculates the Q value, Q The value represents the expected long-term reward of all actions:

[0148]

[0149] in, Q express Q value, π Indicates strategy, Q π Indicates the adoption strategy π of Q value, E represents the expectation operation, r t+1 Indicates t +1 reward for the iteration, c Represents the discount factor.

[0150] S707: In the target network, use a deep neural network to optimize Q The value function is fitted, the optimal Q The value function is specifically:

[0151]

[0152] in, Q * Indicates the best Q value, max means taking the maximum value, r t+2 Indicates t +Rewards obtained at 2 iterations.

[0153] S708: Randomly extract small batches of samples from the experience pool.

[0154] S709: Construct mean square error loss function:

[0155]

[0156] in, L represents the mean square error loss function, i t Indicates t The target network parameters at the iteration time are: Indicates t The online network parameters at the iteration, D represents the experience pool, M Represents the number of samples drawn from the experience pool.

[0157] S710: Update the target network parameters using gradient descent.

[0158]

[0159] in, i t+1 Indicates t +1 target network parameters at iteration, r represents the learning rate, Represents a gradient operation.

[0160] S711: According to the best Q The value function controls the sedimentation process to maintain an optimal deposition rate ratio between the first deposition source material and the second deposition source material.

[0161] In the present invention, the DRL agent can sense the state changes during the sedimentation process in real time and dynamically adjust the process parameters according to the current state, so that the sedimentation process is always close to or maintained at the optimal preparation conditions. This dynamic adjustment can effectively respond to environmental fluctuations or changes in material properties, ensuring the stability and consistency of the process.

[0162] S8: When the first deposition source material and the second deposition source material meet on the substrate, a perovskite film is formed through a chemical reaction.

[0163] S9: When the perovskite film on the substrate reaches the target thickness, the heating of the first deposition source material and the second deposition source material is immediately stopped.

[0164] S10: performing annealing treatment on the perovskite film.

[0165] Optionally, the perovskite film is annealed at an optimal annealing temperature determined from the optimal preparation parameters.

[0166] It should be noted that annealing can eliminate defects and stress in the film caused by the deposition process, improve the crystallinity of the film, and form a more ordered crystal structure. High-quality crystal structure helps to improve the light absorption efficiency and charge transfer capacity of the film, thereby improving the efficiency of solar cells.

[0167] In a possible implementation, after S6, the method for preparing a perovskite thin film further includes:

[0168] S11: heating a precursor solution containing metal atoms so that when the first deposition source material, the second deposition source material, and the metal atoms meet on the substrate, a perovskite film doped with metal nanoparticles is formed through a chemical reaction.

[0169] In the present invention, metal nanoparticles (such as silver, gold, etc.) can produce a local surface plasmon resonance (LSPR) effect. This effect enhances the local electric field, thereby improving the ability of the perovskite layer to capture photons, especially in the visible and near-infrared light bands. This means that after the addition of metal nanoparticles, the light absorption efficiency of the perovskite film is significantly improved, thereby improving the photoelectric conversion efficiency.

[0170] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0171] (1) In the present invention, metal halide PbCl2 is used as the first deposition source material and methylammonium iodide MAI is used as the second deposition source material to carry out mixed vacuum evaporation deposition to prepare the perovskite film. Under a vacuum environment, the evaporation rates of PbCl2 and MAI can be very accurately controlled by heating the evaporation source, thereby improving the uniformity of the film thickness and facilitating large-area preparation.

[0172] (2) In the present invention, the photovoltaic performance, uniformity and fatigue strength of the perovskite film are improved, the optimal preparation parameters at various target thicknesses are determined, and during the heating process, the sedimentation process is controlled to remain at the optimal preparation parameters. The deposition process can be precisely controlled to ensure the stability and consistency of the deposition process, which helps to make the thickness of the film uniform and reduce local differences in thickness and composition, thereby improving the overall uniformity, photovoltaic performance and fatigue strength of the film.

[0173] Example 2

[0174] In one embodiment, the reference specification Figure 2 , showing a schematic structural diagram of a perovskite film preparation device provided by the present invention.

[0175] The present invention provides a perovskite film preparation device, which is used to implement the perovskite film preparation method of Example 1. The perovskite film preparation device includes: a shell 1, a substrate fixing table 2, a substrate 3, a substrate shielding plate 4, a first crucible 5, a first heating wire 6, a first sensor 7, a second crucible 8, a second heating wire 9, a second sensor 10, an exhaust system 11 and an intelligent controller 12.

[0176] A vacuum accommodating space is provided inside the housing 1 .

[0177] A substrate fixing platform 2 , a substrate 3 , a substrate shielding plate 4 , a first crucible 5 , a first heating wire 6 , a first sensor 7 , a second crucible 8 , a second heating wire 9 , a second sensor 10 and an intelligent controller 12 are arranged in the accommodating space.

[0178] The substrate fixing platform 2 is fixedly connected to the top surface of the housing 1 .

[0179] A substrate 3 is placed on the substrate fixing table 2 .

[0180] A substrate shielding plate 4 is provided under the substrate fixing table 2, and the substrate shielding plate 4 is used to prevent the deposition source material from being directly deposited on the substrate 3 after being heated, thereby ensuring that the material can be evenly diffused and fully reacted before deposition, thereby improving the uniformity and crystallization quality of the thin film and reducing the formation of defects.

[0181] The first crucible 5 is provided with a first heating wire 6 , and the first deposition source material in the first crucible 5 is heated and evaporated by the first heating wire 6 .

[0182] The first sensor 7 is used to monitor the deposition rate of the first deposition source material.

[0183] The second crucible 8 is provided with a second heating wire 9 , and the second deposition source material in the second crucible 8 is heated and evaporated by the second heating wire 9 .

[0184] It should be noted that the equipment is equipped with an independent first crucible and a second crucible, each of which is equipped with a heating wire and a sensor for heating and monitoring the deposition rate of the first and second deposition source materials. This independent control design allows the equipment to accurately adjust the deposition rate of each material, thereby ensuring the uniformity of the composition and thickness of the perovskite film.

[0185] The second sensor 10 is used to monitor the deposition rate of the second deposition source material.

[0186] The exhaust system 11 is connected to the interior of the housing 1 through a pipeline, and the exhaust system 11 is used to accurately control the deposition rate of the second deposition source material.

[0187] The intelligent controller 12 is connected to the first heating wire 6 , the second heating wire 9 and the exhaust system 11 .

[0188] It should be noted that the intelligent controller is connected to the heating wire and the exhaust system, and can automatically adjust the heating power and exhaust rate according to the real-time monitoring data. This automatic control reduces human intervention, improves the stability and repeatability of the process, and thus ensures high-quality film preparation.

[0189] In a possible implementation manner, the perovskite thin film preparation device further includes: a partition 13 .

[0190] The partition 13 is disposed between the first crucible 5 and the second crucible 8 , and is used to avoid thermal cross interference between the first deposition source material and the second deposition source material during the evaporation process.

[0191] It should be noted that the partition 13 can effectively block the heat radiation and conduction of the two deposition source materials during the heating and evaporation process to avoid thermal cross interference. By reducing thermal cross interference, the partition can help maintain the temperature uniformity in each crucible and prevent the influence of temperature fluctuations on the evaporation rate of the material, thereby helping to form a more uniform film.

[0192] In a possible implementation, the perovskite film preparation device further includes: a third crucible 14, a third heating wire 15 and a third sensor 16;

[0193] The third crucible 14 is provided with a third heating wire 15, and the precursor solution containing metal atoms in the third crucible 14 is heated and evaporated by the third heating wire 15;

[0194] The third sensor 16 is used to monitor the deposition rate of metal atoms evaporated from the precursor solution.

[0195] Furthermore, the precursor solution containing metal atoms is heated so that when the first deposition source material, the second deposition source material and the metal atoms meet on the substrate, a perovskite film doped with metal nanoparticles is formed through a chemical reaction.

[0196] It should be noted that metal nanoparticles such as silver and gold can produce local surface plasmon resonance (LSPR) effects. This effect enhances the local electric field, thereby improving the perovskite layer's ability to capture photons, especially in the visible and near-infrared bands. This means that after the incorporation of metal nanoparticles, the light absorption efficiency of the perovskite film is significantly improved, thereby improving the photoelectric conversion efficiency.

[0197] Furthermore, a partition 13 may also be disposed between the third crucible 14 and the first crucible 5 to avoid thermal cross-interference between the first deposition source material and the metal atoms during the evaporation process.

[0198] A perovskite film preparation system provided by the present invention can realize the steps and effects of the perovskite film preparation method in the above-mentioned embodiment 1. To avoid repetition, the present invention will not go into details.

[0199] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0200] (1) In the present invention, metal halide PbCl2 is used as the first deposition source material and methylammonium iodide MAI is used as the second deposition source material to carry out mixed vacuum evaporation deposition to prepare the perovskite film. Under a vacuum environment, the evaporation rates of PbCl2 and MAI can be very accurately controlled by heating the evaporation source, thereby improving the uniformity of the film thickness and facilitating large-area preparation.

[0201] (2) In the present invention, the photovoltaic performance, uniformity and fatigue strength of the perovskite film are improved, the optimal preparation parameters at various target thicknesses are determined, and during the heating process, the sedimentation process is controlled to remain at the optimal preparation parameters. This can accurately control the deposition process, ensure the stability and consistency of the deposition process, help to make the thickness of the film uniform, reduce local differences in thickness and composition, and thus improve the overall uniformity, photovoltaic performance and fatigue strength of the film.

[0202] Example 3

[0203] In one embodiment, the present invention provides a solar cell, which is provided with a perovskite film prepared by the perovskite film preparation method described in Example 1.

[0204] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0205] (1) In the present invention, metal halide PbCl2 is used as the first deposition source material and methylammonium iodide MAI is used as the second deposition source material to carry out mixed vacuum evaporation deposition to prepare the perovskite film. Under a vacuum environment, the evaporation rates of PbCl2 and MAI can be very accurately controlled by heating the evaporation source, thereby improving the uniformity of the film thickness and facilitating large-area preparation.

[0206] (2) In the present invention, the photovoltaic performance, uniformity and fatigue strength of the perovskite film are improved, the optimal preparation parameters at various target thicknesses are determined, and during the heating process, the sedimentation process is controlled to remain at the optimal preparation parameters. This can accurately control the deposition process, ensure the stability and consistency of the deposition process, help to make the thickness of the film uniform, reduce local differences in thickness and composition, and thus improve the overall uniformity, photovoltaic performance and fatigue strength of the film.

[0207] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0208] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a perovskite film, characterized in that: include: S1: using metal halide PbCl2 as the first deposition source material and methylammonium iodide MAI as the second deposition source material; S2: setting the target thickness of the perovskite film to be prepared; S3: To improve the photovoltaic performance, uniformity and fatigue strength of the perovskite film, determine the optimal preparation parameters at various target thicknesses; S4: cleaning the substrate and mounting it on the substrate fixing table; S5: heating the substrate; S6: first heating the first deposition source material, and monitoring the deposition rate of the first deposition source material through a first sensor; S7: subsequently heating the second deposition source material, and monitoring the deposition rate of the second deposition source material by a second sensor, and during the heating process, controlling the sedimentation process to maintain at the optimal preparation parameters; S8: when the first deposition source material and the second deposition source material meet on the substrate, a perovskite film is formed through a chemical reaction; S9: when the perovskite film on the substrate reaches the target thickness, immediately stop heating the first deposition source material and the second deposition source material; S10: annealing the perovskite film; Wherein, the S3 specifically includes: S301: Construct objective functions to improve the photovoltaic performance, uniformity and fatigue strength of perovskite films; S302: Determine the optimal preparation parameters under various target thicknesses by using a particle swarm optimization algorithm with the goal of maximizing the objective function; Wherein, the objective function is specifically: in, f represents the objective function, b 1 represents photovoltaic performance parameters, b 2 represents the uniformity parameter, b 3 represents fatigue strength parameter, β 1 represents the weight coefficient of photovoltaic performance parameters, β 2 represents the weight coefficient of the uniformity parameter, β 3 represents the weight coefficient of fatigue strength parameter; Wherein, the S302 specifically includes: The objective function is the fitness function of the particle swarm optimization algorithm; Initial particle group, the particle group contains multiple particles, each particle represents a preparation parameter combination; Calculate the fitness value of each particle; Determine the position of the particle with the highest fitness value as the global optimal position; The position of each particle is updated according to the following formula: in, Indicates i The particle in t The particle position at iteration +1, Indicates i The particle in t The displacement vector at the iteration, exp represents the exponential function with the natural constant as the base, s Represents the shape parameter, which is a random number between -1 and 1. r represents the logarithmic spiral constant, P best represents the global optimal position, δ represents the attraction factor, Indicates t The global optimal position at the iteration; Wherein, the displacement vector is specifically: Where MMI represents mutual information, sim Represents Euclidean distance similarity; The mutual information is specifically: in, H represents information entropy, Indicates i The particle in t The information entropy of the particle position at the iteration, Indicates t The information entropy of the global optimal position at the iteration is Indicates i The particle in t The joint information entropy with the global optimal position at the iteration; Determine whether the maximum number of iterations has been reached; if so, output the preparation parameters represented by the particle with the highest fitness value as the optimal preparation parameters; otherwise, return to continue iterating.

2. The method for preparing a perovskite thin film according to claim 1, characterized in that: After S6, the method further includes: S11: heating a precursor solution containing metal atoms so that when the first deposition source material, the second deposition source material, and the metal atoms meet on the substrate, a perovskite film doped with metal nanoparticles is formed through a chemical reaction.

3. The method for preparing a perovskite thin film according to claim 1, characterized in that: The controlled sedimentation process in S7 is maintained at the optimal preparation parameters, specifically: Through a deep reinforcement learning-based intelligent agent, the sedimentation process is controlled to remain within the optimal preparation parameters.

4. The method for preparing a perovskite thin film according to claim 3, characterized in that: The controlling sedimentation process in S7 is maintained at the optimal preparation parameters, specifically comprising: S701: Constructing the environment space of the intelligent agent: in, s Indicates the environment, s 1 represents the deposition rate of the first deposition source material, s 2 represents the deposition rate of the second deposition source material, s 3 represents the deposition rate ratio between the first deposition source material and the second deposition source material; S702: Constructing the action space of the agent: in, a Indicates action, a 1 indicates adjusting the heating power of the first heating wire, wherein the first heating wire is used to heat and evaporate the first deposition source material. a 2 indicates adjusting the heating power of the second heating wire, the second heating wire is used to heat and evaporate the second deposition source material, a 3 represents adjusting the power of the exhaust system, wherein the exhaust system is used to control the deposition rate of the second deposition source material; S703: Construct a reward function for the agent, where the reward function is used to provide a reward or punishment for the agent according to the result of the action execution. Specifically, the reward function is: in, r represents the reward function, r 1 represents the energy consumption reward function, r 2 represents the deposition rate proportional reward function, λ 1 represents the weight coefficient of the energy consumption reward function, λ 2 represents the weight coefficient of the deposition rate proportional reward function; S704: In the online network, use ε -greedy strategy in the environment s t Next select an action a t , s t Indicates t The environment at the time of the iteration, a t Indicates t The action selected at the iteration; S705: Execute action a t , get reward r t , r t Indicates t The reward obtained at the iteration; S706: When this As t The parameters at each moment are stored in the experience pool; S707: Introduction Q Function, calculates the Q value, Q The value represents the expected long-term reward of all actions: in, Q express Q value, π Indicates strategy, Q π Indicates the adoption strategy π of Q value, E represents the expectation operation, r t+1 Indicates t +1 reward for the iteration, γ represents the discount factor; S707: In the target network, use a deep neural network to optimize Q The optimal value function is fitted. Q The value function is specifically: in, Q * Indicates the best Q value, max means taking the maximum value, r t+2 Indicates t +Rewards obtained in 2 iterations; S708: Randomly draw small batches of samples from the experience pool; S709: Construct mean square error loss function: in, L represents the mean square error loss function, θ t Indicates t The target network parameters at the iteration time are: Indicates t The online network parameters at the iteration, D represents the experience pool, M represents the number of samples drawn from the experience pool; S710: Update the target network parameters using gradient descent: in, θ t+1 Indicates t +1 target network parameters at iteration, ρ t Indicates t The learning rate at the iteration, represents the gradient operation; S711: According to the optimal Q The value function controls the sedimentation process to maintain an optimal deposition rate ratio between the first deposition source material and the second deposition source material.

5. A perovskite film preparation device, characterized in that: Used to implement the method for preparing a perovskite thin film according to any one of claims 1 to 4, the perovskite thin film preparation device comprising: a housing (1), a substrate fixing table (2), a substrate (3), a substrate shielding plate (4), a first crucible (5), a first heating wire (6), a first sensor (7), a second crucible (8), a second heating wire (9), a second sensor (10), an exhaust system (11) and an intelligent controller (12); A vacuum accommodating space is provided inside the housing (1); The accommodating space is provided with the substrate fixing platform (2), the substrate (3), the substrate shielding plate (4), the first crucible (5), the first heating wire (6), the first sensor (7), the second crucible (8), the second heating wire (9), the second sensor (10) and the intelligent controller (12); The substrate fixing platform (2) is fixedly connected to the top surface of the shell (1); The substrate (3) is arranged on the substrate fixing platform (2); The substrate shielding plate (4) is arranged below the substrate fixing platform (2), and the substrate shielding plate (4) is used to prevent the deposition source material from being directly deposited on the substrate (3) after being heated; The first crucible (5) is provided with the first heating wire (6), and the first deposition source material in the first crucible (5) is heated and evaporated by the first heating wire (6); The first sensor (7) is used to monitor the deposition rate of the first deposition source material; The second crucible (8) is provided with the second heating wire (9), and the second deposition source material in the second crucible (8) is heated and evaporated by the second heating wire (9); The second sensor (10) is used to monitor the deposition rate of the second deposition source material; The exhaust system (11) is connected to the interior of the housing (1) via a pipeline, and the exhaust system (11) is used to accurately control the deposition rate of the second deposition source material; The intelligent controller (12) is connected to the first heating wire (6), the second heating wire (9) and the air extraction system (11).

6. The perovskite thin film preparation device according to claim 5, characterized in that: Also includes: Partition (13); The partition (13) is arranged between the first crucible (5) and the second crucible (8), and the partition (13) is used to avoid thermal cross interference between the first deposition source material and the second deposition source material during the evaporation process.

7. The perovskite thin film preparation device according to claim 5, characterized in that: Also includes: A third crucible (14), a third heating wire (15), and a third sensor (16); The third crucible (14) is provided with the third heating wire (15), and the precursor solution containing metal atoms in the third crucible (14) is heated and evaporated by the third heating wire (15); The third sensor (16) is used to monitor the deposition rate of metal atoms evaporated from the precursor solution.

8. A solar cell, characterized in that: A perovskite film prepared by the perovskite film preparation method according to any one of claims 1 to 4 is provided.

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