A method for preparing a perovskite device

Abstract

The present invention provides a method for preparing a perovskite device, comprising the following steps: depositing a metal halide film using a dry process, the dry process including a first deposition stage and a second deposition stage, depositing a first sub-film layer in the first deposition stage, depositing a second sub-film layer located on the surface of the first sub-film layer in the second deposition stage, a first deposition rate in the first deposition stage being greater than a second deposition rate in the second deposition stage, a thickness of the first sub-film layer being greater than a thickness of the second sub-film layer, and a thickness of the second sub-film layer being 20 nm to 50 nm; forming an organic liquid film on the surface of the metal halide film using a wet process, the organic liquid film containing a methylamine group or an amine group; and annealing the organic liquid film to obtain a perovskite film. The perovskite film has both a large metal halide conversion degree and a flat surface, which is beneficial to improving the performance of the perovskite device.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite devices, and in particular to a method for preparing a perovskite device. Background Art

[0002] In recent years, environmental pollution and energy shortages have become a global concern. Solar energy, with its abundant reserves, widespread distribution, renewable nature, and pollution-free nature, is considered a key solution to these problems. Solar cells, as an effective way to harness solar energy, rely on the photovoltaic effect to directly convert solar radiation into electrical energy. Perovskite solar cells (PSCs) are a new type of solar cell with significant advantages, including low manufacturing costs and high photoelectric conversion efficiency. Due to their consistently high conversion efficiency, PSCs have attracted widespread attention, and research into their industrialization is progressing rapidly.

[0003] The light-absorbing layer of a perovskite solar cell is a perovskite film. Methods for preparing perovskite films include a one-step process and a two-step process. The two-step process involves first forming a solid metal halide film with a loose, porous structure; then forming an organic liquid film on the surface of the metal halide film. The organic liquid film penetrates into the pores of the metal halide film and reacts with the metal halide to form the perovskite material; this is then annealed to obtain a solid perovskite film. This indicates that the porosity of the metal halide film directly affects the penetration of the organic liquid film, thereby affecting the degree of metal halide conversion and, in turn, the quality of the perovskite film. Currently, the process for forming metal halide films involves a dry process.

[0004] However, the metal halide films currently prepared by dry processes cannot have both appropriate porosity and a relatively flat surface, which limits the quality of perovskite films and even the performance of perovskite solar cells. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is how to improve the performance of perovskite solar cells, thereby providing a method for preparing a perovskite device.

[0006] The present invention provides a method for preparing a perovskite device, comprising the following steps: depositing a metal halide film using a dry process, the dry process comprising a first deposition stage and a second deposition stage performed in sequence, wherein the first deposition stage deposits a first sub-film layer, and the second deposition stage deposits a second sub-film layer located on a side surface of the first sub-film layer, a first deposition rate in the first deposition stage is greater than a second deposition rate in the second deposition stage, a thickness of the first sub-film layer is greater than a thickness of the second sub-film layer, and a thickness of the second sub-film layer is 20 nm-50 nm; forming an organic liquid film on the surface of the metal halide film using a wet process, wherein the organic liquid film contains a methylamine group or an amine group; and annealing the organic liquid film to obtain a perovskite film.

[0007] Optionally, the first deposition rate is The second deposition rate is

[0008] Optionally, the thickness of the first sub-film layer is 80nm-800nm.

[0009] Optionally, the method for preparing the perovskite device further includes: before forming the organic liquid film, pre-heating the substrate of the perovskite device to increase the temperature of the substrate, the first heating temperature being lower than the annealing temperature; after the substrate of the perovskite device is first heated, forming an organic liquid film on the surface of the metal halide film.

[0010] Optionally, the first heating temperature is 40° C.-100° C.; the annealing temperature is 100° C.-200° C.; and the annealing time is 5 min-30 min.

[0011] Optionally, the method for preparing the perovskite device further includes: before forming the organic liquid film, pre-heating the organic solution used to form the organic liquid film to increase the temperature of the organic liquid film, and the temperature of the second heating is lower than the annealing temperature.

[0012] Optionally, the second heating temperature is 50°C-100°C.

[0013] Optionally, the dry process includes a vacuum evaporation process, a magnetron sputtering process, a chemical vapor deposition process, an atomic layer deposition process, and a reactive plasma deposition process; the wet process includes a slit coating process, a scraping process, a spraying process, a spin coating process, and an immersion process.

[0014] Optionally, the material of the metal halide film includes lead iodide, cesium iodide, lead bromide, cesium bromide, lead chloride, and cesium chloride; the solute of the organic liquid film includes methylammonium iodide, methylammonium bromide, methylammonium chloride, methylamine iodide, methylamine bromide, methylamine chloride, benzylammonium bromide, phenethylammonium bromide, phenethylammonium chloride, phenylpropylammonium iodide, phenylbutylammonium bromide, methylbutyric acid ammonium, ethylammonium iodide, and butylammonium acetate.

[0015] Optionally, the metal halide film comprises at least two materials, and the dry process is a vacuum co-evaporation process.

[0016] Optionally, the perovskite device includes a single-junction perovskite solar cell and a stacked perovskite solar cell.

[0017] Optionally, the perovskite solar cell has a regular structure or a trans structure.

[0018] The technical solution of the present invention has the following advantages:

[0019] 1. The preparation method of the perovskite device provided by the present invention comprises the following steps: in the process of depositing a metal halide film by a dry process, firstly, a metal halide having a large thickness is deposited at a slower deposition rate to obtain a first sub-film layer, so as to ensure that the first sub-film layer located below has a large porosity; then, a metal halide having a small thickness is deposited on a side surface of the first sub-film layer at a faster deposition rate to obtain a second sub-film layer, so as to ensure that the upper surface of the metal halide film is relatively flat; by limiting the thickness of the second sub-film layer to 20nm-50nm, the penetration effect of the organic liquid film is ensured, and after the organic liquid film penetrates the pores of the metal halide film, the metal halide film is converted into a perovskite material; the larger porosity in the first sub-film layer can increase the degree of conversion of the metal halide, and the flat surface of the second sub-film layer can increase the surface flatness of the perovskite film, thereby improving the contact effect between the perovskite film and the functional layer located on the surface of the perovskite film, that is, the perovskite film has both a large degree of metal halide conversion and a flat surface, has a high quality, and is conducive to improving the performance of the perovskite device.

[0020] 2. The preparation method of the perovskite device provided by the present invention promotes the infiltration of the organic liquid film and improves the effect of the organic liquid film penetrating into the pores of the first sub-membrane layer through the pores of the second sub-membrane layer, thereby further improving the degree of conversion of metal halide and further improving the performance of the perovskite device by pre-heating the substrate of the perovskite device to increase the temperature of the substrate before forming the organic liquid film, and / or pre-heating the organic solution used to form the organic liquid film to increase the temperature of the organic liquid film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A flow chart for preparing a perovskite layer according to an embodiment of the present invention;

[0023] Figure 2 for Figure 1 Schematic diagram of the structure of the prepared perovskite solar cell;

[0024] Description of reference numerals:

[0025] 1-substrate; 2-first electrode layer; 3-first carrier transport layer; 4-perovskite layer; 5-second carrier transport layer; 6-second electrode layer. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The terms "first", "second" and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0027] As described in the background, metal halide films currently produced using dry processes lack both appropriate porosity and a relatively flat surface, limiting the quality of perovskite films and, ultimately, the performance of perovskite solar cells. Specifically, the porosity and surface flatness of metal halide films produced using dry processes are related to the metal halide deposition rate. If the deposition rate of the metal halide is slow, the metal halide film is dense and flat. The flat surface can improve the surface flatness of the perovskite film, thereby improving the contact effect between the perovskite film and other functional layers, which is beneficial to the performance of the perovskite solar cell. However, the dense metal halide film is not conducive to the penetration of the organic liquid film, resulting in a low degree of metal halide conversion. A large amount of metal halide remains in the perovskite film, which is not conducive to the performance of the perovskite solar cell. If the deposition rate of the metal halide is fast, the metal halide film is relatively loose and has a rough surface. The loose metal halide film improves the degree of metal halide conversion. However, the rough surface of the metal halide film is not conducive to the surface flatness of the perovskite film, thereby affecting the contact effect between the perovskite film and other functional layers. That is, it is difficult to prepare a metal halide film with both appropriate porosity and a flat surface using the current dry process.

[0028] Based on this, this embodiment provides a method for preparing a perovskite device, comprising the following steps: depositing a metal halide film using a dry process, the dry process comprising a first deposition stage and a second deposition stage performed sequentially, the first deposition stage depositing a first sub-film layer, and the second deposition stage depositing a second sub-film layer located on one side surface of the first sub-film layer, the first deposition rate of the first deposition stage being greater than the second deposition rate of the second deposition stage, the thickness of the first sub-film layer being greater than the thickness of the second sub-film layer, and the thickness of the second sub-film layer being 20nm-50nm; forming an organic liquid film on the surface of the metal halide film using a wet process, the organic liquid film containing a methylamine group or an amine group; and annealing the organic liquid film to obtain a perovskite film.

[0029] In the preparation method of the above-mentioned perovskite device, in the process of depositing the metal halide film using a dry process, a metal halide with a larger thickness is first deposited at a slower deposition rate to obtain a first sub-film layer to ensure that the first sub-film layer located below has a larger porosity; then a metal halide with a smaller thickness is deposited on the side surface of the first sub-film layer at a faster deposition rate to obtain a second sub-film layer to ensure that the upper surface of the metal halide film is relatively flat; by limiting the thickness of the second sub-film layer to 20nm-50nm, the penetration effect of the organic liquid film is guaranteed, and after the organic liquid film penetrates the pores of the metal halide film, the metal halide film is converted into a perovskite material; the larger porosity in the first sub-film layer can increase the conversion degree of the metal halide, and the flat surface of the second sub-film layer can increase the surface flatness of the perovskite film, thereby improving the contact effect between the perovskite film and the functional layer located on the surface of the perovskite film, that is, the perovskite film has both a larger metal halide conversion degree and a flat surface, has higher quality, and is conducive to improving the performance of the perovskite device.

[0030] Specifically, the perovskite device includes but is not limited to a single-junction perovskite solar cell and a stacked perovskite solar cell.

[0031] The following combination Figure 1-Figure 2 , taking perovskite solar cells as an example, the preparation method of perovskite devices is clearly and completely explained.

[0032] Step S1: providing a substrate 1.

[0033] Specifically, substrate 1 includes, but is not limited to, glass, heterojunction cells, crystalline silicon cells, or thin-film solar cells; thin-film solar cells include, but are not limited to, copper indium gallium selenide thin-film solar cells, cadmium telluride thin-film solar cells, gallium arsenide thin-film solar cells, and perovskite solar cells; and crystalline silicon cells include, but are not limited to, N-type single-crystal passivated contact cells (TopCon cells). When substrate 1 is glass, the resulting cell is a single-junction perovskite solar cell; when substrate 1 is a heterojunction cell, crystalline silicon cell, or thin-film solar cell, the resulting cell is a tandem cell.

[0034] Step S2 : forming a first electrode layer 2 on one surface of the substrate 1 .

[0035] Specifically, the material of the first electrode layer 2 includes but is not limited to fluorine-doped tin oxide (FTO) or indium tin oxide (ITO); the process of forming the first electrode layer 2 on one side surface of the substrate 1 includes but is not limited to magnetic sputtering process or chemical vapor deposition process.

[0036] It should be understood that when the substrate 1 is made of glass and the material of the first electrode layer 2 is FTO or ITO, commercial FTO conductive glass or ITO conductive glass can be directly used; before depositing other materials on the surface of the first electrode layer 2, the conductive glass needs to be pretreated to remove impurities on the surface of the first electrode layer 2. The above pretreatment includes ultrasonic treatment with glass detergent, wiping with a soft brush, ultrasonic treatment with ultrapure water, ultrasonic treatment with ethanol, drying and ultraviolet ozone treatment in sequence.

[0037] Step S3 : forming a first carrier transport layer 3 on a surface of the first electrode layer 2 facing away from the substrate 1 .

[0038] Specifically, the process for forming the first carrier transport layer 3 includes but is not limited to spin coating, coating, spraying, vacuum evaporation, magnetron sputtering, and atomic layer deposition. The specific process can be selected according to the material of the first carrier transport layer 3.

[0039] Step S4 : forming a perovskite layer 4 on the surface of the first carrier transport layer 3 facing away from the substrate 1 .

[0040] For details, see Figure 1 , the steps of forming the perovskite layer 4 include:

[0041] Step S41: A metal halide film is deposited on the surface of the first carrier transport layer 3 facing away from the substrate 1 using a dry process. The specific deposition process includes a first deposition stage and a second deposition stage performed in sequence. In the first deposition stage, a first sub-film layer is deposited on the surface of the first carrier transport layer 3 facing away from the substrate 1. In the second deposition stage, a second sub-film layer is deposited on the surface of the first sub-film layer facing away from the substrate 1. The thickness of the first sub-film layer is greater than the thickness of the second sub-film layer, and the first deposition rate in the first deposition stage is greater than the second deposition rate in the second deposition stage.

[0042] Specifically, the material of the metal halide film includes but is not limited to lead iodide, cesium iodide, lead bromide, cesium bromide, lead chloride, and cesium chloride; the thickness of the first sub-film layer is 80nm-800nm, and the first deposition rate is The thickness of the second sub-film layer is 20nm-50nm, and the second deposition rate is For example, the thickness of the first sub-film layer can be 80nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 650nm, 700nm, 750nm or 800nm, and the first deposition rate can be or The thickness of the second sub-film layer can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm, and the second deposition rate can be or Different metal halides can be deposited using different deposition rates.

[0043] It should be understood that a dry process is a process in which the deposited material is not in liquid form when deposited on a substrate. Dry processes include but are not limited to vacuum evaporation processes, magnetron sputtering processes, chemical vapor deposition processes, atomic layer deposition processes, and reactive plasma deposition processes.

[0044] The specific steps of depositing the metal halide film using the vacuum evaporation process are as follows: transferring the sample prepared in step S3 into a vacuum chamber, placing the metal halide in an evaporation source; evacuating the vacuum chamber to remove impurity gases in the vacuum chamber until the vacuum degree of the vacuum chamber is less than 1×10 -6 mbar; fill the vacuum chamber with inert gas or nitrogen until the vacuum degree of the vacuum chamber reaches 2×10 -4The first and second sub-layers are deposited by adjusting the current flowing through the evaporation source to control the deposition rate. After deposition is complete, the current is adjusted to 0. After the temperature in the vacuum chamber drops to room temperature, the vacuum chamber is inflated to equalize the pressure with the ambient air, and the vacuum chamber is opened to remove the sample. Evaporation sources include, but are not limited to, crucibles.

[0045] Furthermore, the material of the metal halide film can be one or more; when the material of the metal halide film includes at least two types, a vacuum co-evaporation process is used to deposit the metal halide film, that is, different metal halides are placed in different evaporation sources, and the temperature of each evaporation source is regulated separately to thereby regulate the components in the metal halide film.

[0046] Step S42: forming an organic liquid film on the surface of the metal halide film by a wet process, wherein the organic liquid film contains methylamine groups or amine groups.

[0047] Specifically, the wet process includes but is not limited to a slit coating process, a doctor blade coating process, a spray coating process, a spin coating process, and an immersion process;

[0048] The solute of the organic solution used to form the organic liquid film includes, but is not limited to, at least one of methylammonium iodide (FAI), methylammonium bromide (FABr), methylammonium chloride (FACl), methylamine iodide (MAI), methylamine bromide (MABr), methylamine chloride (MACl), benzylamine bromide (PMABr), phenethylamine bromide, phenethylamine chloride, phenylpropylamine iodide, phenylbutylamine bromide, methylbutyric acid ammonium, ethylamine iodide, and butylacetamide; the solvent of the organic solution includes at least one of DMF (dimethylformamide) and DMSO (dimethyl sulfoxide); the organic The total concentration of solute in the solution is 0.2mol / L-1.5mol / L; illustratively, the total concentration of solute in the organic solution can be 0.2mol / L, 0.3mol / L, 0.4mol / L, 0.5mol / L, 0.6mol / L, 0.7mol / L, 0.8mol / L, 0.9mol / L, 1mol / L, 1.1mol / L, 1.2mol / L, 1.3mol / L, 1.4mol / L or 1.5mol / L, and the specific concentration is selected according to the specific wet process and the specific material.

[0049] In order to further promote the infiltration of the organic liquid film, the substrate 1 can be preheated before forming the organic liquid film. The temperature of the first heating is lower than the annealing temperature, so that when the organic liquid film is formed, the substrate 1 has a higher temperature, thereby effectively improving the effect of the organic liquid film penetrating into the pores of the first sub-membrane layer through the pores of the second sub-membrane layer. Specifically, the temperature of the first heating is 40°C-100°C; illustratively, the temperature of the first heating can be 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C; by limiting the first heating temperature to be lower than the subsequent annealing temperature of the perovskite film, it is possible to avoid that after the organic liquid film is formed on the surface of the metal halide film, the organic liquid film immediately reacts with the metal halide on the surface of the metal halide film and crystallizes to form a solid perovskite material, thereby affecting the conversion efficiency of the metal halide film.

[0050] To further promote the penetration of the organic liquid film, the organic solution may be preheated for a second time before forming the organic liquid film. The second heating temperature is lower than the annealing temperature, so that the organic liquid film formed on the surface of the metal halide film has a higher temperature, thereby effectively improving the penetration of the organic liquid film through the pores of the second sub-membrane layer into the pores of the first sub-membrane layer. Specifically, the second heating temperature is 50°C-100°C; illustratively, the second heating temperature can be 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C.

[0051] Step S43: annealing the organic liquid film to obtain a perovskite film.

[0052] Specifically, the annealing temperature is 100°C-200°C, and the annealing time is 5 min-30 min; illustratively, the annealing temperature can be 100°C, 125°C, 150°C, 175°C or 200°C, and the annealing time can be 5 min, 10 min, 15 min, 20 min, 25 min or 30 min. The higher the annealing temperature, the shorter the annealing time.

[0053] Step S5 , forming a second carrier transport layer 5 on the surface of the perovskite layer 4 facing away from the substrate 1 .

[0054] Specifically, the process for forming the second carrier transport layer 5 includes but is not limited to spin coating, coating, spraying, vacuum evaporation, magnetron sputtering, and atomic layer deposition. The specific process can be selected according to the material of the second carrier transport layer 5.

[0055] It should be understood that one of the first carrier transport layer 3 and the second carrier transport layer 5 is a hole transport layer, and the other is an electron transport layer; when the first carrier transport layer 3 is a hole transport layer and the second carrier transport layer 5 is an electron transport layer, the perovskite cell is an inverted perovskite solar cell; when the first carrier transport layer 3 is an electron transport layer and the second carrier transport layer 5 is a hole transport layer, the perovskite cell is a formal perovskite solar cell.

[0056] The materials of the hole transport layer include inorganic hole transport materials and organic hole transport materials; inorganic hole transport materials include but are not limited to NiO x , CuSCN, Cu2O, or CuI; organic hole transport materials include, but are not limited to, polythiophene materials, triphenylmethane materials, and butadiene materials. The thickness of the hole transport layer is 5 nm to 40 nm; illustratively, the thickness of the hole transport layer can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, or 40 nm.

[0057] The materials of the electron transport layer include inorganic electron transport materials and organic electron transport materials; inorganic electron transport materials include but are not limited to titanium dioxide, tin dioxide or zinc oxide; organic electron transport materials include but are not limited to fullerene C70, fullerene C60, [6,6]-phenyl-C71-butyric acid methyl ester (PC 71 BM), [6,6]-phenyl-C61-butyric acid methyl ester (PC 61 BM), double

[60] PCBM. The thickness of the electron transport layer is 5 nm to 40 nm. For example, the thickness of the electron transport layer can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm or 40 nm.

[0058] Step S6: forming a second electrode layer 6 on the surface of the second carrier transport layer 5 facing away from the substrate 1 to obtain a perovskite solar cell.

[0059] Specifically, the materials of the second electrode layer 6 include but are not limited to Au, Ag, Cu, Al, transparent conductive materials, and carbon. The transparent conductive materials include but are not limited to fluorine-doped tin oxide (FTO) and indium tin oxide (ITO). The process for forming the second electrode layer 6 includes but is not limited to vacuum evaporation process, magnetron sputtering process, and screen printing process. The specific process can be selected according to the material of the second electrode layer 6, etc.

[0060] It should be noted that the perovskite layer 4 in other perovskite devices can also be prepared using the above-mentioned preparation method of the perovskite layer 4.

[0061] The following provides specific embodiments to clearly and completely describe the technical solutions of the present invention. The described embodiments are only part of the embodiments of the present invention, but not all of the embodiments.

[0062] Example 1

[0063] This embodiment provides a method for preparing a perovskite solar cell, comprising the following steps:

[0064] The FTO conductive glass was sequentially subjected to ultrasonic treatment with glass cleaning agent, wiping with a soft brush, ultrasonic treatment with ultrapure water, ultrasonic treatment with ethanol, drying, and ultraviolet ozone treatment;

[0065] A 20 nm thick nickel oxide was deposited on the surface of the FTO layer of the FTO conductive glass using a magnetron sputtering process as a hole transport layer.

[0066] A lead iodide film was formed on the surface of the hole transport layer facing away from the FTO conductive glass using a vacuum evaporation process. The specific steps were as follows: the sample prepared in the above steps was transferred into a vacuum chamber, and lead iodide was placed in a crucible; the vacuum chamber was evacuated to a vacuum degree of less than 1×10 -6 mbar, stop evacuating; fill the vacuum chamber with nitrogen until the vacuum degree of the vacuum chamber reaches 2×10 -4 mbar to stop the inflation; adjust the evaporation rate of lead iodide, first with 400 nm was deposited at a deposition rate of The deposition rate is 50 nm, and then the deposition is stopped; after the temperature in the vacuum chamber drops to room temperature, the vacuum chamber is inflated to balance the pressure of the vacuum chamber with that of the outside air, and then the vacuum chamber is opened to take out the sample;

[0067] An organic liquid film was formed on the side of the lead iodide film facing away from the FTO conductive glass using a spray coating process. The organic solution used to form the organic liquid film included 0.4 mol / L FAI, 0.1 mol / L FABr, and 0.1 mol / L MACl, and the solvent was ethanol.

[0068] The sample prepared in the above steps was annealed at 150°C for 15 min to obtain an 800 nm thick perovskite layer;

[0069] Vacuum evaporation process was used to form 30nm thick C layers on the surface of the perovskite layer away from the FTO conductive glass. 60 layer, a 10nm thick BCP (bathcopper) layer and a 200nm thick silver layer, the BCP layer is located at the C 60 The silver layer is located on the side of the BCP layer away from the perovskite layer, and the silver layer is located on the side of the BCP layer away from the perovskite layer to obtain a perovskite solar cell.

[0070] Example 2

[0071] This embodiment provides a method for preparing a perovskite solar cell, which differs from the perovskite solar cell provided in Example 1 in that: before spraying the organic solution onto the surface of the lead iodide film, the organic solution is preheated to stabilize it at 60°C, and then the organic solution is sprayed onto the surface of the lead iodide film.

[0072] Example 3

[0073] This embodiment provides a method for preparing a perovskite solar cell. The difference between this method and the perovskite solar cell provided in Example 1 is that before spraying the organic solution onto the surface of the lead iodide film, the sample on which the lead iodide film has been deposited is preheated to stabilize it at 60°C, and then the organic solution is sprayed onto the surface of the lead iodide film with a higher temperature.

[0074] Example 4

[0075] This embodiment provides a method for preparing a perovskite solar cell, which differs from the perovskite solar cell provided in Example 1 in that:

[0076] The deposition steps of lead iodide film are as follows: first 600nm was deposited at a deposition rate of The deposition rate is 20 nm;

[0077] The organic solution used to form the organic liquid membrane includes 0.48 mol / L FAI, 0.12 mol / L FABr and 0.12 mol / L MACl;

[0078] Finally, a 1100nm thick perovskite layer was prepared.

[0079] Comparative Example 1

[0080] This comparative example provides a method for preparing a perovskite solar cell, which differs from the perovskite solar cell provided in Example 1 in that: A 450 nm thick lead iodide film was deposited at a deposition rate of .

[0081] Comparative Example 2

[0082] This comparative example provides a method for preparing a perovskite solar cell, which differs from the perovskite solar cell provided in Example 1 in that: A 450 nm thick lead iodide film was deposited at a deposition rate of .

[0083] Comparative Example 3

[0084] This comparative example provides a method for preparing a perovskite solar cell, which differs from the perovskite solar cell provided in Example 4 in that: A 620 nm thick lead iodide film was deposited at a deposition rate of .

[0085] Test Example 1

[0086] The perovskite solar cells prepared in Examples 1-3 and Comparative Examples 1-4 were tested for photoelectric conversion efficiency under standard test conditions (1.5 AM) with the scanning direction being reverse scan. The test results are shown in Table 1. Wherein, Voc represents the open circuit voltage, Jsc represents the short circuit current density, FF represents the fill factor, and PCE represents the photoelectric conversion efficiency.

[0087] Table 1

[0088] Voc(V) <![CDATA[Jsc(mA / cm 2 )]]> FF(%) PCE (%) Example 1 1.17 21.24 80.03 20.04 Example 2 1.21 21.41 79.34 20.55 Example 3 1.20 21.09 80.51 20.37 Example 4 1.11 22.48 76.11 18.99 Comparative Example 1 1.06 20.85 72.66 16.11 Comparative Example 2 1.11 19.09 66.93 14.18 Comparative Example 3 1.08 21.86 75.34 17.92

[0089] As can be seen from Table 1, depositing the lead iodide film at a deposition rate that is first fast and then slow can improve the open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cell to a certain extent; before spraying the organic solution on the surface of the lead iodide film, pre-heating the sample on which the lead iodide film has been deposited or heating the organic solution is beneficial for the organic solution to penetrate into the pores of the lead iodide film, thereby improving the conversion degree of the lead iodide film and further improving the photoelectric conversion efficiency of the perovskite solar cell.

[0090] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite device, characterized in that: The following steps are involved: A metal halide film is deposited using a dry process, the dry process comprising a first deposition stage and a second deposition stage performed sequentially, wherein the first deposition stage deposits a first sub-film layer, and the second deposition stage deposits a second sub-film layer located on a side surface of the first sub-film layer, a first deposition rate in the first deposition stage is greater than a second deposition rate in the second deposition stage, a surface of the second sub-film layer facing away from the first sub-film layer is relatively flat, a thickness of the first sub-film layer is greater than a thickness of the second sub-film layer, and a thickness of the second sub-film layer is 20 nm to 50 nm; forming an organic liquid film on the surface of the metal halide film by a wet process, wherein the organic liquid film contains a methylamine group or an amine group; The organic liquid film is annealed to obtain a perovskite film.

2. The method for preparing a perovskite device according to claim 1, wherein: The first deposition rate is 3Å / s-30Å / s, and the second deposition rate is 0.5Å / s-3Å / s.

3. The method for preparing a perovskite device according to claim 1, wherein: The thickness of the first sub-film layer is 80nm-800nm.

4. The method for preparing a perovskite device according to claim 1, wherein: Also includes: Before forming the organic liquid film, the substrate of the perovskite device is pre-heated for the first time to increase the temperature of the substrate, and the temperature of the first heating is lower than the annealing temperature; after the substrate of the perovskite device is pre-heated for the first time, an organic liquid film is formed on the surface of the metal halide film.

5. The method for preparing a perovskite device according to claim 4, wherein: The temperature of the first heating is 40° C.-100° C.; the temperature of the annealing is 100° C.-200° C.; and the annealing time is 5 min-30 min.

6. The method for preparing a perovskite device according to any one of claims 1 to 5, characterized in that: Also includes: Before forming the organic liquid film, the organic solution used to form the organic liquid film is pre-heated for a second time to increase the temperature of the organic liquid film. The temperature of the second heating is lower than the annealing temperature.

7. The method for preparing a perovskite device according to claim 6, wherein: The second heating temperature is 50°C-100°C.

8. The method for preparing a perovskite device according to claim 1, wherein: The dry process includes vacuum evaporation process, magnetron sputtering process, chemical vapor deposition process, atomic layer deposition process, reactive plasma deposition process; The wet process includes a slit coating process, a blade coating process, a spray coating process, a spin coating process, and an immersion process.

9. The method for preparing a perovskite device according to claim 1, wherein: The material of the metal halide film includes lead iodide, cesium iodide, lead bromide, cesium bromide, lead chloride, and cesium chloride; The solutes of the organic liquid membrane include methylammonium iodide, methylammonium bromide, methylammonium chloride, methylamine iodide, methylamine bromide, methylamine chloride, benzylamine bromide, phenethylamine bromide, phenethylamine chloride, phenylpropylamine iodide, phenylbutylamine bromide, methylbutyric acid ammonium, ethylamine iodide, and butylamine acetate.

10. The method for preparing a perovskite device according to claim 9, wherein: The metal halide film comprises at least two materials, and the dry process is a vacuum co-evaporation process.

11. The method for preparing a perovskite device according to any one of claims 1 to 5, characterized in that: The perovskite device includes a single-junction perovskite solar cell and a stacked perovskite solar cell.

12. The method for preparing a perovskite device according to claim 11, wherein: The perovskite solar cell has a regular structure or a trans structure.

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