Perovskite cell and preparation method thereof

Abstract

The invention discloses a perovskite battery and a preparation method thereof, and relates to the technical field of perovskite battery preparation. The preparation method of the perovskite cell comprises a crystallization process of a perovskite precursor solution on a substrate, the method specifically comprises the following steps: volatilizing solvent vapor in a perovskite precursor solution in a cavity, diluting and removing the solvent vapor in the cavity, repeatedly volatilizing and diluting and adjusting specific parameters to enable the perovskite precursor solution to reach a saturated state, further diluting the solvent vapor, crystallizing and annealing. According to the preparation method of the mesoporous perovskite battery, controllable volatilization of the solvent in the perovskite precursor solution is achieved, controllable crystallization and growth are achieved, heating is not needed, the time node and the growth rate of crystallization starting of the solution can be controlled only by controlling the negative pressure or a dry air program, operation is easy, the requirement for equipment is low, and the cost is low. The production cost is low, and the industrial application prospect is relatively good.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite battery preparation, and particularly relates to a perovskite battery and a preparation method thereof. Background Art

[0002] Perovskite solar cells have received extensive attention due to many advantages such as high absorption coefficient, adjustable bandgap, low exciton binding energy, long carrier diffusion radius, and solution processability. With the increase in the thickness of the perovskite layer, it brings challenges to the uniform filling of perovskite during the preparation process of perovskite batteries, and the crystallization process of perovskite materials is difficult to grasp, resulting in many defects; especially for perovskite batteries with a mesoporous structure, the precursor solution dispersed in the mesopores has irreversibly increased defects during the annealing process; most of the existing perovskite crystallization technologies only target the heat treatment annealing of planar structure or single-layer mesoporous structure perovskite batteries, while the crystallization process of multi-layer mesoporous structure or single-layer mesoporous structure with a larger thickness has significantly different principles and processes from that of the conventional planar structure. The thickness of the mesoporous layer filled with perovskite is generally 3 to 4 times the thickness of the active layer of the planar structure perovskite battery. Using the crystallization technology for planar structures cannot solve the technical problem of obvious concentration differences between the surface and the bottom of the perovskite liquid film.

[0003] In the prior art, two patents with publication numbers CN116002989A and CN113788629B rely on solvent atmosphere-assisted crystallization, and limit the evaporation space through specific tools to limit the evaporation rate. However, the above technologies have high requirements for the environment and equipment, and the entire crystallization process is extremely susceptible to the environment and is difficult to effectively control. Summary of the Invention

[0004] The main object of the present invention is to develop a perovskite battery and a preparation method, which can achieve the orderly crystallization and uniform growth of perovskite solution on a mesoporous structure substrate or a planar substrate, so as to realize the uniform filling of perovskite materials.

[0005] To achieve the above object, the present invention provides a preparation method of a perovskite battery. The preparation method of the perovskite battery includes a crystallization process of a perovskite precursor solution on a substrate, and the crystallization process specifically includes the following steps: S10. Provide a cavity, introduce a dry gas to clean the inside of the cavity, and keep the inside of the cavity in a dry state; S20. Place the substrate coated with the perovskite precursor solution inside the cavity, keep the cavity in a closed state, and let it stand. The solvent in the perovskite precursor solution evaporates into solvent vapor inside the cavity, and the concentration of the solvent vapor inside the cavity gradually increases; S30. Wait until the solvent vapor reaches a saturated state inside the cavity, release the airtight state of the cavity, and dilute the solvent vapor inside the cavity; S40. Wait until the perovskite precursor solution completes crystallization and is annealed to form a perovskite layer.

[0006] In one embodiment, in step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-90) to (-50) KPa, and the dilution time lasts for 0.8 to 2 h.

[0007] In one embodiment, the concentration of halide in the perovskite precursor solution is 1 to 2 M, and the dosage of the perovskite precursor solution is 2 to 3 μL / cm 2 。

[0008] In one embodiment, the planar area of the substrate is 40 to 4000 cm 2 。

[0009] In one embodiment, the volume of the cavity is 1 to 100 L.

[0010] In one embodiment, in step S40, during the crystallization process, the temperature inside the cavity is 25 to 35 °C.

[0011] In one embodiment, in step S40, during the annealing process, the annealing temperature is 80 to 120 °C, and the annealing time is 10 to 15 min.

[0012] In one embodiment, the crystallization process of the perovskite precursor solution on the substrate specifically includes: S10. Provide a cavity, introduce dry gas to clean the inside of the cavity, and keep the inside of the cavity in a dry state; S20. Place the substrate coated with the perovskite precursor solution inside the cavity, keep the cavity airtight, and let it stand. The solvent in the perovskite precursor solution volatilizes into solvent vapor inside the cavity, and the concentration of the solvent vapor inside the cavity gradually increases; S30. Wait until the solvent vapor reaches a saturated state inside the cavity, release the airtight state of the cavity, and dilute the solvent vapor inside the cavity; S31. Wait until crystallization begins to appear on the liquid film surface of the perovskite precursor solution, change the cavity to an airtight state and let it stand, and the concentration of the solvent vapor inside the cavity gradually increases; S32. Repeat step S30 and step S31 in sequence; S33. When the perovskite precursor solution reaches the saturation state, dilute the solvent vapor so that the perovskite precursor solution starts to crystallize; S40. When the perovskite precursor solution finishes crystallization, perform annealing treatment to form a perovskite layer.

[0013] In one embodiment, in step S31, when crystallization phenomenon starts to appear on the surface of the perovskite precursor solution, the liquid film color or glossiness of the perovskite precursor solution changes.

[0014] In one embodiment, in step S33, when the perovskite precursor solution reaches the saturation state, the liquid film of the precursor solution changes from a transparent state to an opaque state under the static state, and a complex with a yellowish color appears.

[0015] In one embodiment, in step S30, when diluting the solvent vapor, the dilution time is 10 - 60 min; and / or, in step S31, when changing the cavity to a closed state and standing, the standing time is 5 - 10 min; and / or, in step S33, when diluting the solvent vapor, the dilution time lasts for 0.33 - 15 h.

[0016] In one embodiment, the substrate is a mesoporous substrate; In step S30, when diluting the solvent vapor, it includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-90) - (-50) KPa; in step S32, repeating steps S30 and S31: each time when evacuating the cavity, maintain the internal negative pressure of the cavity to decrease successively, and the decreasing amplitude is 1 - 10 KPa; in step S33, when diluting the solvent vapor, it includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-20) - (-10) KPa.

[0017] And / or, in step S30, when diluting the solvent vapor, it includes: introducing dry gas into the cavity, while discharging the gas inside the cavity, keeping the gas flow rate of the introduced dry gas and the discharged gas inside the cavity consistent, and maintaining the gas flow rate at 10 - 100 mL / min; in step S32, repeating steps S30 and S31: each time when introducing dry gas into the cavity, maintain the gas flow rate to decrease successively, and the decreasing amplitude is 1 - 10 mL / min; in step S33, when diluting the solvent vapor, it includes: introducing dry gas into the cavity and maintaining the gas flow rate at 0.01 - 1 mL / min.

[0018] In one embodiment, the substrate is a planar substrate; In step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-70) to (-50) KPa; in step S32, repeating steps S30 and S31: each time the cavity is evacuated, maintaining the internal negative pressure of the cavity decreases gradually, with a decrease amplitude of 1 to 10 KPa; in step S33, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-40) to (-10) KPa; And / or, in step S30, diluting the solvent vapor includes: introducing dry gas into the cavity while discharging the internal gas of the cavity, keeping the gas flow rates of the introduced dry gas and the discharged internal gas of the cavity consistent, and maintaining the gas flow rate at 20 to 50 mL / min; in step S32, repeating steps S30 and S31: each time dry gas is introduced into the cavity, maintaining the gas flow rate decreases gradually, with a decrease amplitude of 1 to 10 mL / min; in step S33, diluting the solvent vapor includes: introducing dry gas into the cavity and maintaining the gas flow rate at 1 to 10 mL / min.

[0019] The present invention also provides a perovskite solar cell, which is prepared by the preparation method of the perovskite solar cell.

[0020] The technical solution in the present invention designs a perovskite solar cell and its preparation method. Compared with the conventional planar structure or mesoporous structure perovskite solar cell annealed under heat treatment conditions of about 100°C, the preparation method of the perovskite solar cell in the present invention realizes the controllable volatilization of the solvent in the perovskite precursor solution by regulating the removal rate of the solvent vapor in the cavity, so as to achieve the purpose of controllable crystallization and growth; the gradient pressure / flow regulation method developed in the present invention can gradually reduce the negative pressure inside the cavity or gradually increase the gas flow rate introduced into the cavity or do both at the same time, eliminating the concentration difference between the surface and the bottom of the perovskite liquid film on the substrate, thereby realizing controllable crystallization and growth; during the perovskite crystallization process in the present invention, heating is not required, and only by controlling the negative pressure or the dry air program, the time node and growth rate of the solution starting to crystallize can be controlled. The long-term low-vacuum negative pressure will not damage the quality of the perovskite film. The operation is simple, the equipment requirements are low, the production cost is low, and it has good industrial application prospects. Description of the Drawings

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0022] Figure 1 It is the current density-voltage curve of the device obtained in Example 1; Figure 2 It is the current density-voltage curve of the device obtained in Example 2; Figure 3 It is the current density-voltage curve of the device obtained in Example 3; Figure 4 It is the current density-voltage curve of the device obtained in Example 4; Figure 5 It is the current density-voltage curve of the device obtained in Example 5; Figure 6 It is the current density-voltage curve of the device obtained in Example 6; Figure 7 It is the current density-voltage curve of the device obtained in Example 7; Figure 8 It is the current density-voltage curve of the device obtained in Example 8; Figure 9 It is the current density-voltage curve of the device obtained in Example 9; Figure 10 It is the current density-voltage curve of the device obtained in Example 10; Figure 11 It is the current density-voltage curve of the device obtained in Example 11; Figure 12 It is the current density-voltage curve of the device obtained in Example 12; Figure 13 It is the current density-voltage curve of the device obtained in Example 13; Figure 14 It is the current density-voltage curve of the device obtained in Example 14; Figure 15 It is the current density-voltage curve of the device obtained in Comparative Example 1; Figure 16 It is the current density-voltage curve of the device obtained in Comparative Example 2; Figure 17 It is the current density-voltage curve of the device obtained in Comparative Example 3; Figure 18The current density-voltage curve of the device prepared in Comparative Example 4; Figure 19 The current density-voltage curve of the device prepared in Comparative Example 5; Figure 20 The current density-voltage curve of the device prepared in Comparative Example 6.

[0023] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0026] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0027] The technical problem solved by the present application is that the existing perovskite crystallization technology mainly focuses on the heat treatment annealing of perovskite solar cells with planar structure or single-layer mesoporous structure. However, the crystallization process of perovskite solar cells with multi-layer mesoporous structure or single-layer mesoporous structure with larger thickness has significantly different principles and processes from those of conventional planar structures. Using the crystallization technology for planar structures cannot solve the technical problem of obvious concentration differences on the surface and bottom of the perovskite liquid film.

[0028] To solve the above technical problems, a perovskite solar cell and a preparation method thereof are designed, which can realize the ordered crystallization and uniform growth of the perovskite solution on the surface of the substrate, so as to realize the uniform filling of the perovskite material.

[0029] The present invention provides a preparation method of a perovskite solar cell. The preparation method of the perovskite solar cell includes a crystallization process of a perovskite precursor solution on a substrate. The crystallization process specifically includes the following steps: S10: Provide a cavity, introduce a dry gas to clean the inside of the cavity, and keep the inside of the cavity in a dry state; S20: Place the substrate coated with the perovskite precursor solution inside the cavity, keep the cavity in a closed state, and let it stand. The solvent in the perovskite precursor solution volatilizes into solvent vapor inside the cavity, and the concentration of the solvent vapor inside the cavity gradually increases; S30: When the solvent vapor reaches a saturated state inside the cavity, release the closed state of the cavity and dilute the solvent vapor inside the cavity; S40: After the perovskite precursor solution is crystallized, perform annealing treatment to form a perovskite layer.

[0030] It should be noted that the preparation method of the perovskite solar cell in the present invention is particularly suitable for preparing a perovskite solar cell with a mesoporous structure, and is also applicable to the preparation of a planar perovskite solar cell; compared with the conventional preparation method of a planar perovskite solar cell, the present invention enables the perovskite crystal to grow slowly and fully through a relatively longer crystallization time, with larger grain size, which can reduce defects such as grain boundaries, and has better performance than the planar perovskite solar cell or the mesoporous perovskite solar cell prepared by the conventional method. For specific details, please refer to the embodiment part of the present invention.

[0031] In one embodiment, in step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-90) to (-50) KPa, and the dilution time lasts for 0.8 to 2 h. It should be noted that the preparation method in this embodiment is only applicable to the preparation of the perovskite layer on a planar substrate, but in this embodiment, only by creating a long-term negative pressure to quickly evaporate the solvent, the requirements for filling the perovskite in the mesoporous structure cannot be met.

[0032] In one embodiment, the concentration of the halide in the perovskite precursor solution is 1 to 2 M, and the dosage of the perovskite precursor solution is 2 to 3 μL / cm 2 ; and / or, the planar area of the substrate is 40 to 4000 cm 2; and / or, the volume of the cavity is 1~100L; and / or, in step S40, the temperature inside the cavity during the crystallization process is 25~35℃.

[0033] It should be noted that since it is difficult to ensure temperature uniformity in a large space at high temperature, the present invention uniquely controls the concentration change of solvent vapor in a confined space at a relatively low constant temperature to regulate the removal rate of solvent vapor in the cavity, thereby achieving controllable volatilization of the solvent and achieving the purpose of controllable crystallization and growth of perovskite crystals.

[0034] In one embodiment, in the step S40, during the annealing process, the annealing temperature is 80-120° C., and the annealing time is 10-15 min.

[0035] In one embodiment, the crystallization process of the perovskite precursor solution on the substrate specifically includes: S10, providing a cavity, introducing dry gas to clean the interior of the cavity, and keeping the interior of the cavity in a dry state; S20, placing the substrate coated with the perovskite precursor solution inside the cavity, keeping the cavity in a sealed state, and standing, the solvent in the perovskite precursor solution evaporates into solvent vapor inside the cavity, and the concentration of the solvent vapor inside the cavity gradually increases; S30, when the solvent vapor reaches a saturated state inside the cavity, releasing the sealed state of the cavity and diluting the solvent vapor inside the cavity; S31, when crystallization begins to appear on the surface of the liquid film of the perovskite precursor solution, the cavity is sealed and left to stand, and the concentration of the solvent vapor in the cavity gradually increases; S32, repeating step S30 and step S31 in sequence; S33, when the perovskite precursor solution reaches a saturated state, diluting the solvent vapor to allow the perovskite precursor solution to begin crystallization; S40, after the perovskite precursor solution is completely crystallized, annealing treatment is performed to form a perovskite layer.

[0036] It should be noted that at a certain temperature, in a closed space with a fixed volume, the saturated vapor pressure of the solvent is fixed. When the saturated vapor pressure is reached, the solvent no longer volatilizes and is in a gas-liquid equilibrium state. At this time, slowly removing the solvent vapor or diluting the partial pressure of the gas in the space will break the original gas-liquid equilibrium of the solvent. At this time, the vapor pressure of the solvent in the closed space is less than the saturated vapor pressure, and the solvent will continue to volatilize; in the preparation method of the perovskite battery of the present invention, the controllable volatilization of the solvent in the perovskite precursor solution is achieved by regulating the removal rate of the solvent vapor in the cavity, so as to achieve the purpose of controllable crystallization and growth; the gradient pressure / flow regulation method developed in the present invention can gradually reduce the negative pressure inside the cavity or gradually increase the gas flow rate into the cavity or perform both at the same time, eliminating the concentration difference between the surface and the bottom of the perovskite liquid film in the mesoporous substrate, thereby realizing controllable crystallization and growth.

[0037] It should also be noted that in order to precisely control the above crystallization process, parameters such as the temperature during the above crystallization process, the amount of the perovskite precursor solution, the volume of the closed space, i.e., the cavity, and the area of the mesoporous substrate need to be limited at the same time in order to use the preparation method in the present invention to prepare a mesoporous perovskite battery with better optoelectronic performance; it should also be noted that the present invention only explores the crystallization process within the above parameters, including the cavity volume range, the solution amount range, the area of the mesoporous substrate, and the temperature range during the crystallization process; it should also be noted that in the crystallization process of the present invention, the specific vapor pressure-temperature-volume curve of the solvent vapor is not within the scope of discussion of this patent.

[0038] In one embodiment, in step S31, when crystallization begins to appear on the surface of the perovskite precursor solution, the color or gloss of the liquid film of the perovskite precursor solution changes. It should be noted that in step S31, when the surface solubility of the perovskite liquid film is close to saturation, at this time, the color or gloss of the film surface changes, that is, crystals will begin to precipitate from the surface layer solution of the liquid film, and the dilution of the solvent vapor should be stopped immediately.

[0039] In one embodiment, in step S33, when the perovskite precursor solution reaches a saturated state, the liquid film of the precursor solution changes from a transparent state to an opaque state and a complex with a yellowish color appears under a static state. It should be noted that in step S6, the perovskite solution begins to crystallize and nucleate to precipitate black perovskite grains and grow continuously, so the liquid film changes from a transparent state to an opaque state.

[0040] In one embodiment, in step S30, the solvent vapor is diluted, and the dilution time is 10 to 60 minutes.

[0041] In one embodiment, in step S31, the cavity is made airtight and left standing, and the standing time is 5 to 10 minutes.

[0042] In one embodiment, in step S33, the solvent vapor is diluted, and the dilution time lasts for 0.33 to 15 hours.

[0043] In one embodiment, the substrate is a mesoporous substrate, and the crystallization process of perovskite is adjusted by the method of gradient negative pressure: in step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-90) to (-50) KPa; in step S32, repeating steps S30 and S31: each time the cavity is evacuated, the negative pressure inside the cavity is gradually reduced, and the reduction amplitude is 1 to 10 KPa; in step S33, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-20) to (-10) KPa.

[0044] It should be noted that each time steps S30 and S31 are repeated in step S32, the concentration of the perovskite solution will increase and gradually approach the saturation concentration. Therefore, it is necessary to weaken the negative pressure state inside the cavity and continuously keep the concentration difference between the bottom and the surface of the perovskite liquid film in a small state to prevent a large amount of perovskite from precipitating in a short time due to supersaturation of the solution, so as to control the crystallization growth rate of perovskite.

[0045] In one embodiment, the substrate is a mesoporous substrate, and the crystallization process of perovskite is adjusted by the method of gradient flow: in step S30, diluting the solvent vapor includes: introducing dry gas into the cavity while discharging the gas inside the cavity, keeping the gas flow rate of the introduced dry gas and the discharged gas inside the cavity consistent, and maintaining the gas flow rate at 10 to 100 mL / min; in step S32, repeating steps S30 and S31: each time dry gas is introduced into the cavity, the gas flow rate is gradually reduced, and the reduction amplitude is 1 to 10 mL / min; in step S33, diluting the solvent vapor includes: introducing dry gas into the cavity and maintaining the gas flow rate at 0.01 to 1 mL / min.

[0046] It should be noted that in steps S30, S32, and S33, in order to keep the internal air pressure of the cavity unchanged, it is necessary to discharge the gas inside the cavity while introducing gas, and keep the gas flow rate of the introduced dry gas and the discharged gas inside the cavity consistent.

[0047] It should be noted that each repetition of steps S30 and S31 in step S32 increases the concentration of the perovskite solution, causing it to continuously approach the saturation concentration. Therefore, it is necessary to continuously reduce the gas flow rates of the inlet and outlet gases, slow down the solvent evaporation, and continuously maintain a small concentration difference between the bottom and the surface of the perovskite liquid film to prevent a large amount of perovskite from precipitating in a short time due to supersaturation of the solution, thereby achieving the control of the perovskite crystal growth rate.

[0048] In one embodiment, the substrate is a mesoporous substrate, and the crystallization process of perovskite is adjusted by a method combining gradient negative pressure and gradient flow rate: in step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-90) to (-50) KPa, and introducing dry gas into the cavity while exhausting the internal gas of the cavity, keeping the gas flow rates of the introduced dry gas and the exhausted internal gas of the cavity consistent, and maintaining the gas flow rate at 10 to 100 mL / min; in step S32, repeating steps S30 and S31: each time the cavity is evacuated, maintaining the negative pressure inside the cavity decreases successively, with a decrease amplitude of 1 to 10 KPa, and each time dry gas is introduced into the cavity, maintaining the gas flow rate decreases successively, with a decrease amplitude of 1 to 10 mL / min; in step S33, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-20) to (-10) KPa, and introducing dry gas into the cavity and maintaining the gas flow rate at 0.01 to 1 mL / min.

[0049] In one embodiment, the substrate is a planar substrate, and the crystallization process of perovskite is adjusted by the method of gradient negative pressure: in step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-70) to (-50) KPa; in step S32, repeating steps S30 and S31: each time the cavity is evacuated, maintaining the negative pressure inside the cavity decreases successively, with a decrease amplitude of 1 to 10 KPa; in step S33, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal air pressure of the cavity at (-40) to (-10) KPa.

[0050] In one embodiment, the substrate is a planar substrate, and the crystallization process of perovskite is adjusted by the method of gradient flow rate: in step S30, diluting the solvent vapor includes: introducing dry gas into the cavity while exhausting the gas inside the cavity, and keeping the gas flow rate of the introduced dry gas and the exhausted gas inside the cavity consistent, and maintaining the gas flow rate at 20-50 mL / min; in step S32, repeating steps S30 and S31: each time dry gas is introduced into the cavity, the gas flow rate is gradually decreased, and the decreasing amplitude is 1-10 mL / min; in step S33, diluting the solvent vapor includes: introducing dry gas into the cavity and maintaining the gas flow rate at 1-10 mL / min.

[0051] In one embodiment, the substrate is a planar substrate, and the crystallization process of perovskite is adjusted by the method combining gradient negative pressure and gradient flow rate: in step S30, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal pressure of the cavity at (-70)-(-50) KPa, and introducing dry gas into the cavity while exhausting the gas inside the cavity, and keeping the gas flow rate of the introduced dry gas and the exhausted gas inside the cavity consistent, and maintaining the gas flow rate at 20-50 mL / min; in step S32, repeating steps S30 and S31: each time the cavity is evacuated, the negative pressure inside the cavity is gradually decreased, and the decreasing amplitude is 1-10 KPa, and each time dry gas is introduced into the cavity, the gas flow rate is gradually decreased, and the decreasing amplitude is 1-10 mL / min; in step S33, diluting the solvent vapor includes: evacuating the cavity and maintaining the internal pressure of the cavity at (-40)-(-10) KPa, and introducing dry gas into the cavity and maintaining the gas flow rate at 1-10 mL / min.

[0052] It should be noted that in order to achieve precise control of the above crystallization process, parameters such as the temperature in the above crystallization process, the dosage of the perovskite precursor solution, the volume of the closed space (i.e., the cavity), and the area of the mesoporous substrate need to be limited simultaneously in order to prepare a mesoporous perovskite battery with better optoelectronic performance using the preparation method of the present invention; it should also be noted that the present invention only explores the crystallization process within the above parameters, including the cavity volume range, the solution volume range, the area of the mesoporous substrate, and the temperature range during crystallization; it should also be noted that in the crystallization process of the present invention, the specific vapor pressure-temperature-volume curve of the solvent vapor is not within the scope of discussion of this patent.

[0053] The present invention also provides a perovskite solar cell prepared by the method for preparing a perovskite solar cell described above. By adopting the above preparation method, the perovskite layer in the prepared perovskite solar cell has good uniformity and high density.

[0054] The following further illustrates the present invention through specific examples: The raw materials used in the embodiments of the present invention are all commercially available, and the present invention does not impose any special restrictions on the sources of the raw materials.

[0055] The mesoporous substrates used in the embodiments and comparative examples of this application include titanium dioxide porous membranes, zirconia porous membranes, and porous carbon membranes; among them, the porosity of the titanium dioxide porous membrane is about 70%, the porosity of the zirconia porous membrane is about 60%, and the porosity of the porous carbon membrane is about 70%.

[0056] Example 1 The perovskite solar cell prepared in Example 1 has a mesoporous structure.

[0057] The preparation of the perovskite precursor solution in Example 1 includes the following steps: Dissolve 19.5 mg of CsI, 244.7 mg of FAI, and 691.5 mg of PbI2 in 1.5 mL of a mixed solution of DMF and DMSO with a volume ratio of 8:2, and stir at room temperature for 10 h to obtain a perovskite precursor solution with a halide concentration of 1 M.

[0058] The preparation method of the mesoporous perovskite solar cell in Example 1 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium dioxide porous membrane with a thickness of 0.8 μm, a zirconia porous membrane with a thickness of 2.5 μm, and a porous carbon membrane with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 10 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Coat the perovskite precursor solution with an initial concentration of 1 M onto the mesoporous substrate with a unit coating amount of 3 ul / cm 2 and a total effective area of 40 cm 2 , and place the mesoporous substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min; S30. Wait until the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -90 KPa, and maintain it for about 30 min; S31. When the surface color or gloss of the perovskite precursor solution film changes (i.e., crystallization begins), stop the air extraction operation in step S30, and at the same time change the cavity to a closed state and let it stand for 10 min; S32. Repeat steps S30 and S31; wherein, during each air extraction process of the cavity, compared with the previous air extraction process, maintain the internal negative pressure of the cavity decreasing successively, and the decreasing amplitude is 5 KPa; S33. When the internal air pressure of the cavity becomes -40 KPa, the perovskite precursor solution reaches a saturated state, and the film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop step S32, and reduce the internal negative pressure of the cavity to -20 KPa and keep it for 10 h to crystallize the perovskite precursor solution; S40. After crystallization is completed, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer, and spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer in sequence to prepare a perovskite solar cell.

[0059] Example 2 The perovskite solar cell prepared in Example 2 has a mesoporous structure, and the preparation of the perovskite precursor solution in Example 2 is the same as that in Example 1.

[0060] The preparation method of the mesoporous perovskite solar cell in Example 2 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 10 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Coat the perovskite precursor solution with an initial concentration of 1 M onto the mesoporous substrate with a unit coating amount of 3 μl / cm 2 and a total effective area of 40 cm 2 , and place the mesoporous substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, introduce dry gas into the air inlet of the cavity while exhausting the gas inside the cavity containing solvent vapor through the air outlet, and the gas flow rates of ventilation and exhaust are the same. The initial gas flow rate is 100 ml / min, and keep the above state for about 30 min; S31. When the surface color or gloss of the perovskite precursor solution film changes (i.e., crystallization begins), stop the operation in step S30. At the same time, change the cavity to a closed state and let it stand for 10 min. S32. Repeat steps S30 and S31 in sequence. Among them, during each ventilation process of the cavity, compared with the previous ventilation process, the gas flow rate is gradually decreased, and the decrease amplitude is 5 ml / min. S33. When the gas flow rate becomes 50 ml / min, the perovskite precursor solution reaches a saturated state, and the film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop step S32. At this time, directly reduce the gas flow rate to 1 ml / min and keep it for 15 h to crystallize the perovskite precursor solution. S40. After crystallization is completed, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer. Spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer in sequence to prepare a perovskite solar cell.

[0061] Example 3 The perovskite solar cell prepared in Example 3 has a mesoporous structure, and the preparation of the perovskite precursor solution in Example 3 is the same as that in Example 1.

[0062] The preparation method of the mesoporous perovskite solar cell in Example 3 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 10 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry. S20. Coat the perovskite precursor solution with an initial concentration of 1 M onto the mesoporous substrate at a unit coating amount of 3 μl / cm 2 on a total effective area of 40 cm 2 , and place the mesoporous substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min. S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -90 KPa. At the same time, introduce dry gas into the air inlet inside the cavity and discharge the gas inside the cavity containing solvent vapor through the air outlet. The gas flow rates of ventilation and exhaust are the same, and the initial gas flow rate is 100 ml / min. Keep the above state for about 10 min. S31. When the surface color or gloss of the perovskite precursor solution film changes (i.e., crystallization starts), stop the operation in step S30. At the same time, change the cavity to a closed state and let it stand for 10 min. S32. Repeat steps S30 and S31 in sequence. During each evacuation process of the cavity, compared with the previous evacuation process, maintain the internal negative pressure of the cavity decreasing gradually, with the decrease amplitude being 5 KPa. At the same time, during each ventilation process of the cavity, compared with the previous ventilation process, maintain the gas flow rate decreasing gradually, with the decrease amplitude being 10 ml / min. S33. When the internal air pressure of the cavity becomes -50 KPa and the gas flow rate becomes 20 ml / min, the perovskite precursor solution reaches a saturated state, and the film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop step S32. At this time, directly reduce the internal negative pressure of the cavity to -10 KPa and directly reduce the gas flow rate to 1 ml / min, and continue for 10 h to crystallize the perovskite precursor solution. S40. After crystallization is completed, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer. Spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer in sequence to prepare a perovskite solar cell.

[0063] Example 4 The perovskite solar cell prepared in Example 4 has a mesoporous structure, and the preparation of the perovskite precursor solution in Example 4 is the same as that in Example 1.

[0064] The preparation method of the mesoporous perovskite solar cell in Example 4 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 1 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry. S20. Coat the perovskite precursor solution with an initial concentration of 1 M onto the mesoporous substrate with a unit coating amount of 3 μl / cm 2 and a total effective area of 1 cm 2 , and place the mesoporous substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min. S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa, and keep it for about 10 min. S31. When the surface color or gloss of the liquid film of the perovskite precursor solution changes (i.e., crystallization starts), stop the air extraction operation in step S30, and at the same time change the cavity to a closed state and let it stand for 10 min; S32. Repeat steps S30 and S31 in sequence; wherein, during each air extraction process of the cavity, compared with the previous air extraction process, the internal negative pressure of the cavity is gradually reduced, and the reduction amplitude is 5 KPa; S33. When the internal air pressure of the cavity becomes -20 KPa, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop step S32, and directly reduce the internal negative pressure of the cavity to -10 KPa at this time, and keep it for 5 h to crystallize the perovskite precursor solution; S40. After crystallization is completed, heat the mesoporous substrate at 100 °C for 10 min, spin-coat Spiro and evaporate and deposit a gold electrode in sequence to prepare a perovskite solar cell.

[0065] Example 5 The perovskite solar cell prepared in Example 5 has a mesoporous structure. The preparation of the perovskite precursor solution in Example 5 is the same as that in Example 1, except that the perovskite concentration is 1.4 M.

[0066] The preparation method of the mesoporous perovskite solar cell in Example 5 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 1 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Coat the perovskite precursor solution with an initial concentration of 1.4 M onto the mesoporous substrate with a unit coating amount of 3 ul / cm 2 on a total effective area of 1 cm 2 , and place the mesoporous substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -50 KPa, and keep it for about 10 min; S31. When the surface color or gloss of the liquid film of the perovskite precursor solution changes (i.e., crystallization starts), stop the air extraction operation in step S30, and at the same time change the cavity to a closed state and let it stand for 10 min; S32. Repeat the steps S30 and S31 successively; wherein, during each evacuation process of the cavity, compared with the previous evacuation process, the negative pressure inside the cavity is maintained to decrease successively, and the decreasing amplitude is 5 KPa; S33. When the air pressure inside the cavity becomes -15 KPa, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop the step S32. At this time, directly reduce the negative pressure inside the cavity to -10 KPa and keep it for 5 h to crystallize the perovskite precursor solution; S40. After crystallization is completed, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer, and spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer in sequence to prepare a perovskite solar cell.

[0067] Example 6 The perovskite solar cell prepared in Example 6 has a mesoporous structure, and the preparation of the perovskite precursor solution in Example 6 is the same as that in Example 1.

[0068] The preparation method of the mesoporous perovskite solar cell in Example 6 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 50 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Coat the perovskite precursor solution with an initial concentration of 1 M onto the mesoporous substrate with a unit coating amount of 3 μl / cm 2 and a total effective area of 200 cm 2 , and place the mesoporous substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -90 KPa, and keep it for about 60 min; S31. When the color or gloss of the liquid film surface of the perovskite precursor solution changes (i.e., crystallization starts), stop the evacuation operation in the step S30, and at the same time change the cavity to a closed state and let it stand for 10 min; S32. Repeat the steps S30 and S31 successively; wherein, during each evacuation process of the cavity, compared with the previous evacuation process, the negative pressure inside the cavity is maintained to decrease successively, and the decreasing amplitude is 5 KPa; S33. When the internal air pressure of the cavity becomes -30 KPa, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop step S32. At this time, directly reduce the negative pressure inside the cavity to -10 KPa and keep it for 10 h to crystallize the perovskite precursor solution. S40. After crystallization is completed, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer. Spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer in sequence to fabricate a perovskite solar cell.

[0069] Example 7 The perovskite solar cell fabricated in Example 7 has a planar regular structure, and the preparation of the perovskite precursor solution in Example 7 is the same as that in Example 1.

[0070] The preparation method of the perovskite solar cell in Example 7 includes the following steps: S10. Take a conductive glass, deposit a dense titanium oxide layer with a thickness of about 50 nm on the conductive layer to form a substrate. Place the substrate in a closed cavity with a volume of 5 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry. S20. Spin-coat a perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 , and place the substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min. S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa and keep it for about 10 min. S31. When the color or glossiness of the liquid film surface of the perovskite precursor solution changes (i.e., crystallization begins), stop the evacuation operation in step S30, and at the same time change the cavity to a closed state and let it stand for 10 min. S32. Repeat steps S30 and S31 in sequence; among them, during each evacuation process of the cavity, compared with the previous evacuation process, the negative pressure inside the cavity is gradually reduced, and the reduction amplitude each time is 5 KPa. S33. When the internal air pressure of the cavity becomes -20 KPa, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop step S5. At this time, directly reduce the negative pressure inside the cavity to -10 KPa and keep it for 1 h to crystallize the perovskite precursor solution. S40. Wait for crystallization to be completed, heat the substrate at 100 °C for 10 min to form a perovskite layer, spin-coat Spiro on the surface of the perovskite layer, and evaporate and deposit a gold electrode to fabricate a perovskite solar cell.

[0071] Example 8 The perovskite solar cell fabricated in Example 8 has a planar regular structure, and the preparation of the perovskite precursor solution in Example 8 is the same as that in Example 1.

[0072] The preparation method of the perovskite solar cell in Example 8 includes the following steps: S10. Take a conductive glass, deposit a dense titanium oxide layer with a thickness of about 50 nm on the conductive layer to form a substrate. Place the substrate in a sealed cavity with a volume of 5 L, introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 , and place the substrate inside the cavity, keep the cavity in a sealed state, and let it stand for 20 min; S30. Wait until the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa, and keep it for about 1 h to crystallize the perovskite precursor solution; S40. Wait until all the solvent has evaporated and crystallization is completed, heat the substrate at 100 °C for 10 min to form a perovskite layer, spin-coat a Spiro material and evaporate and deposit a gold electrode on the surface of the perovskite layer to fabricate a perovskite solar cell.

[0073] Example 9 The perovskite solar cell fabricated in Example 9 has a planar regular structure, and the preparation of the perovskite precursor solution in Example 9 is the same as that in Example 1.

[0074] The preparation method of the perovskite solar cell in Example 9 includes the following steps: S10. Take a conductive glass, deposit a dense titanium oxide layer with a thickness of about 50 nm on the conductive layer to form a substrate. Place the substrate in a sealed cavity with a volume of 5 L, introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 , and place the substrate inside the cavity, keep the cavity in a sealed state, and let it stand for 20 min; S30. Wait until the solvent vapor reaches a saturated state inside the cavity. While introducing dry gas into the inlet of the cavity, exhaust the gas inside the cavity containing solvent vapor through the outlet. The gas flow rates for ventilation and exhaust are the same. The initial gas flow rate is 20 ml / min. Maintain the above state for about 10 min. S31. Wait until the color or glossiness of the liquid film surface of the perovskite precursor solution changes (i.e., crystallization begins). Stop the operation in step S30. At the same time, change the cavity to a closed state and let it stand for 10 min. S32. Repeat steps S30 and S31 successively. Among them, during each ventilation process of the cavity, compared with the previous ventilation process, maintain the gas flow rate decreasing gradually, and the decreasing amplitude is 5 ml / min. S33. When the gas flow rate becomes 10 ml / min, the perovskite precursor solution reaches a saturated state. The liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Continue ventilation for about 20 min to crystallize the perovskite precursor solution. S40. Wait until crystallization is completed. Heat the substrate at 100 °C for 10 min to form a perovskite layer. Spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer successively to fabricate a perovskite solar cell.

[0075] Example 10 The perovskite solar cell fabricated in Example 10 has a planar regular structure, and the preparation of the perovskite precursor solution in Example 10 is the same as that in Example 1.

[0076] The preparation method of the perovskite solar cell in Example 10 includes the following steps: S10. Take a conductive glass and deposit a dense titanium oxide layer with a thickness of about 50 nm on the conductive layer to form a substrate. Place the substrate in a closed cavity with a volume of 5 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry. S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 and place the substrate inside the cavity. Keep the cavity in a closed state and let it stand for 20 min. S30. Wait until the solvent vapor reaches a saturated state inside the cavity. Evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa. While introducing dry gas into the inlet of the cavity, exhaust the gas inside the cavity containing solvent vapor through the outlet. The gas flow rates for ventilation and exhaust are the same. The initial gas flow rate is 20 ml / min. Maintain the above state for about 10 min. S31. When the surface color or gloss of the perovskite precursor solution film changes (i.e., crystallization begins), stop the operation in step S30. At the same time, change the cavity to a closed state and let it stand for 10 min. S32. Repeat steps S30 and S31 successively. Among them, during each evacuation process of the cavity, compared with the previous evacuation process, maintain the internal negative pressure of the cavity decreasing gradually, and the decreasing amplitude is 10 KPa. At the same time, during each ventilation process of the cavity, compared with the previous ventilation process, maintain the gas flow rate decreasing gradually, and the decreasing amplitude is 5 ml / min. S33. When the internal air pressure of the cavity becomes -40 KPa and the gas flow rate becomes 10 ml / min, the perovskite precursor solution reaches a saturated state. The film of the perovskite precursor solution changes from a transparent state to an opaque state. Keep the above state for about 20 min to make the perovskite precursor solution start to crystallize. S40. After crystallization is completed, heat the substrate at 100 °C for 10 min to form a perovskite layer. Spin-coat Spiro and evaporate a gold electrode on the surface of the perovskite layer in sequence to obtain a perovskite solar cell.

[0077] Example 11 The perovskite solar cell prepared in Example 11 has a planar inverted structure, and the preparation of the perovskite precursor solution in Example 11 is the same as that in Example 1.

[0078] The preparation method of the perovskite solar cell in Example 11 includes the following steps: S10. Take a conductive glass, deposit a dense nickel oxide layer with a thickness of about 20 nm on the conductive layer to form a substrate. Place the substrate in a closed cavity with a volume of 5 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry. S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 and place the substrate inside the cavity, keep the cavity in a closed state, and let it stand for 20 min. S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa, and keep it for about 10 min. S31. When the surface color or gloss of the perovskite precursor solution film changes (i.e., crystallization begins), stop the evacuation operation in step S30. At the same time, change the cavity to a closed state and let it stand for 10 min. S32. Repeat the steps S30 and S31 successively; wherein, during each evacuation process of the cavity, compared with the previous evacuation process, the internal negative pressure of the cavity is maintained to decrease gradually, with a decrease amplitude of 5 KPa each time. S33. When the internal air pressure of the cavity becomes -20 KPa, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Stop the step S5. At this time, directly reduce the internal negative pressure of the cavity to -10 KPa and maintain it for 1 h to make the perovskite precursor solution start to crystallize. S40. After crystallization is completed, heat the substrate at 100 °C for 10 min to form a perovskite layer. Deposit a dense tin oxide layer (with a thickness of about 50 nm) and evaporate a silver electrode on the surface of the perovskite layer to obtain a perovskite solar cell.

[0079] Example 12 The perovskite solar cell prepared in Example 12 has a planar inverted structure, and the preparation of the perovskite precursor solution in Example 12 is the same as that in Example 1.

[0080] The preparation method of the perovskite solar cell in Example 12 includes the following steps: S10. Take a conductive glass, deposit a dense nickel oxide layer with a thickness of about 20 nm on the conductive layer to form a substrate. Place the substrate in a sealed cavity with a volume of 5 L, and introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry. S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 and place the substrate inside the cavity, keep the cavity in a sealed state, and let it stand for 20 min. S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa, and maintain it for about 1 h to make the perovskite precursor solution crystallize. S40. After the solvent has completely volatilized and crystallization is completed, heat the substrate at 100 °C for 10 min to form a perovskite layer. Deposit a dense tin oxide layer (with a thickness of about 50 nm) and evaporate a silver electrode on the surface of the perovskite layer to obtain a perovskite solar cell.

[0081] Example 13 The perovskite solar cell prepared in Example 13 has a planar inverted structure, and the preparation of the perovskite precursor solution in Example 13 is the same as that in Example 1.

[0082] The preparation method of the perovskite solar cell in Example 13 includes the following steps: S10. Take a conductive glass, deposit a dense nickel oxide layer with a thickness of about 20 nm on the conductive layer to form a substrate. Place the substrate in a sealed cavity with a volume of 5 L, introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Spin-coat a perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 and place the substrate inside the cavity, keep the cavity in a sealed state, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, while introducing dry gas through the inlet of the cavity, exhaust the gas inside the cavity containing the solvent vapor through the outlet. The gas flow rates of ventilation and exhaust are the same, the initial gas flow rate is 20 ml / min, and maintain the above state for about 10 min; S31. When the color or gloss of the liquid film surface of the perovskite precursor solution changes (i.e., crystallization begins), stop the operation in step S30, and at the same time change the cavity to a sealed state and let it stand for 10 min; S32. Repeat steps S30 and S31 in sequence; among them, during each ventilation process of the cavity, compared with the previous ventilation process, the gas flow rate is gradually decreased, and the decrease amplitude is 5 ml / min; S33. When the gas flow rate becomes 10 ml / min, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Continuously ventilate for about 20 min to crystallize the perovskite precursor solution; S40. After crystallization is completed, heat the substrate at 100 °C for 10 min to form a perovskite layer. Deposit a dense tin oxide layer (with a thickness of about 50 nm) and evaporate a silver electrode on the surface of the perovskite layer to obtain a perovskite solar cell.

[0083] Example 14 The perovskite solar cell prepared in Example 14 has a planar inverted structure, and the preparation of the perovskite precursor solution in Example 14 is the same as that in Example 1.

[0084] The preparation method of the perovskite solar cell in Example 14 includes the following steps: S10. Take a conductive glass, deposit a dense nickel oxide layer with a thickness of about 20 nm on the conductive layer to form a substrate. Place the substrate in a sealed cavity with a volume of 5 L, introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Spin-coat a perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2On the substrate, place the substrate inside the cavity, keep the cavity airtight, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa. At the same time, while introducing dry gas into the inlet of the cavity, exhaust the gas inside the cavity containing solvent vapor through the outlet. The gas flow rates for ventilation and exhaust are the same, and the initial gas flow rate is 20 ml / min. Maintain the above state for about 10 min; S31. When the color or gloss of the liquid film surface of the perovskite precursor solution changes (i.e., crystallization starts), stop the operation in step S30. At the same time, make the cavity airtight and let it stand for 10 min; S32. Repeat steps S30 and S31 in sequence; wherein, during each evacuation process of the cavity, compared with the previous evacuation process, the negative pressure inside the cavity is gradually reduced, and the reduction amplitude is 10 KPa; at the same time, during each ventilation process of the cavity, compared with the previous ventilation process, the gas flow rate is gradually reduced, and the reduction amplitude is 5 ml / min; S33. When the air pressure inside the cavity becomes -40 KPa and the gas flow rate becomes 10 ml / min, the perovskite precursor solution reaches a saturated state, and the liquid film of the perovskite precursor solution changes from a transparent state to an opaque state. Maintain the above state for about 20 min to crystallize the perovskite precursor solution; S40. Heat the substrate at 100 °C for 10 min to form a perovskite layer. Deposit a dense tin oxide layer (with a thickness of about 50 nm) and evaporate a silver electrode on the surface of the perovskite layer to obtain a perovskite solar cell.

[0085] Comparative Example 1 The perovskite solar cell prepared in Comparative Example 1 has a mesoporous structure, and the preparation of the perovskite precursor solution in Comparative Example 1 is the same as that in Example 1.

[0086] The preparation method of the perovskite solar cell in Comparative Example 1 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 10 L, introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Coat the perovskite precursor solution with an initial concentration of 1 M at a unit coating amount of 3 ul / cm 2 onto an effective area of 40 cm2 On a mesoporous substrate, and place the mesoporous substrate inside the cavity, keep the cavity airtight, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, evacuate the cavity to make the initial air pressure inside the cavity become -60 KPa, and keep it for about 7 h; complete crystallization, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer, spin-coat Spiro and evaporate and deposit a gold electrode on the surface of the perovskite layer in sequence to obtain a perovskite solar cell.

[0087] Comparative Example 2 The perovskite solar cell prepared in Comparative Example 2 has a mesoporous structure, and the preparation of the perovskite precursor solution in Comparative Example 2 is the same as that in Example 1.

[0088] The preparation method of the perovskite solar cell in Comparative Example 2 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer from bottom to top to form a mesoporous substrate. Place the mesoporous substrate in a closed cavity with a volume of 10 L, introduce dry nitrogen to clean the inside of the cavity for 5 min to keep the inside of the cavity dry; S20. Coat the perovskite precursor solution with an initial concentration of 1 M at a unit coating amount of 3 μl / cm 2 onto the mesoporous substrate with a total effective area of 40 cm 2 and place the mesoporous substrate inside the cavity, keep the cavity airtight, and let it stand for 20 min; S30. When the solvent vapor reaches a saturated state inside the cavity, while introducing dry gas into the air inlet of the cavity, exhaust the gas inside the cavity containing solvent vapor through the air outlet, and the gas flow rates of ventilation and exhaust are the same, and the gas flow rate is 20 ml / min, and keep the above state for about 10 h; confirm that the film layer turns black and no longer changes, complete crystallization, heat the mesoporous substrate at 100 °C for 10 min to form a perovskite layer, spin-coat Spiro and evaporate and deposit a gold electrode on the surface of the perovskite layer in sequence to obtain a perovskite solar cell.

[0089] Comparative Example 3 The perovskite solar cell prepared in Comparative Example 3 has a mesoporous structure, and the preparation of the perovskite precursor solution in Comparative Example 3 is the same as that in Example 1.

[0090] The preparation method of the mesoporous perovskite solar cell in Comparative Example 3 refers to Patent CN116002989A and Patent CN113788629B, and specifically includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer upwards to form a mesoporous substrate; S20. Coat the mesoporous substrate with a perovskite precursor solution with an initial concentration of 1 M at a unit coating amount of 3 μl / cm 2 onto a total effective area of 1 cm 2 , place the mesoporous substrate on a hot stage, cover it with a petri dish lid, and heat it at 57 °C for 20 h to form a perovskite layer. Spin-coat Spiro and evaporate gold electrodes on the surface of the perovskite layer in sequence to obtain a perovskite solar cell.

[0091] Comparative Example 4 The perovskite solar cell prepared in Comparative Example 4 has a mesoporous structure, and the preparation of the perovskite precursor solution in Comparative Example 4 is the same as that in Example 1.

[0092] The preparation method of the perovskite solar cell in Comparative Example 4 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer upwards to form a mesoporous substrate; S20. Coat the mesoporous substrate with a perovskite precursor solution with an initial concentration of 1 M at a unit coating amount of 3 μl / cm 2 onto a total effective area of 1 cm 2 , place the mesoporous substrate in an open environment and heat it at 57 °C for 4 h to form a perovskite layer. Spin-coat Spiro and evaporate gold electrodes on the surface of the perovskite layer in sequence to obtain a perovskite solar cell.

[0093] Comparative Example 5 The perovskite solar cell prepared in Comparative Example 5 has a mesoporous structure, and the preparation of the perovskite precursor solution in Comparative Example 5 is the same as that in Example 1.

[0094] The preparation method of the perovskite solar cell in Comparative Example 5 includes the following steps: S10. Take a conductive glass, and sequentially deposit a dense titanium oxide layer with a thickness of about 50 nm, a titanium oxide porous film with a thickness of 0.8 μm, a zirconium oxide porous film with a thickness of 2.5 μm, and a porous carbon film with a thickness of 25 μm from the conductive layer upwards to form a mesoporous substrate; S20. Coat the mesoporous substrate with a perovskite precursor solution with an initial concentration of 1 M at a unit coating amount of 3 μl / cm 2 onto a total effective area of 5 cm 2On the mesoporous substrate, crystallization is carried out by vacuum flash evaporation. The lowest flash evaporation pressure is maintained at 10 Pa for 20 s to complete crystallization, and then heated at 100 °C for 10 min to form a perovskite layer. Spiro is spin-coated and a gold electrode is evaporated on the surface of the perovskite layer to obtain a perovskite solar cell.

[0095] Comparative Example 6 The perovskite solar cell prepared in Comparative Example 6 has a planar regular structure, and the preparation of the perovskite precursor solution in Comparative Example 6 is the same as that in Example 1.

[0096] The preparation method of the mesoporous perovskite solar cell in Comparative Example 6 specifically includes the following steps: S10. Take a conductive glass, deposit a dense titanium oxide layer with a thickness of about 50 nm on the conductive layer to form a substrate; S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm 2 Crystallization is carried out by vacuum flash evaporation. The lowest flash evaporation pressure is maintained at 10 Pa for 20 s to complete crystallization, and then heated at 100 °C for 10 min to form a perovskite layer. Spiro is spin-coated and a gold electrode is evaporated on the surface of the perovskite layer to obtain a perovskite solar cell.

[0097] Comparative Example 7 The perovskite solar cell prepared in Comparative Example 7 has a planar inverted structure, and the preparation of the perovskite precursor solution in Comparative Example 7 is the same as that in Example 1.

[0098] The preparation method of the mesoporous perovskite solar cell in Comparative Example 7 specifically includes the following steps: S10. Take a conductive glass, deposit a dense nickel oxide layer with a thickness of about 20 nm on the conductive layer to form a substrate; S20. Spin-coat the perovskite precursor solution with an initial concentration of 1 M onto the substrate with an effective area of about 5 cm2. Crystallization is carried out by vacuum flash evaporation. The lowest flash evaporation pressure is maintained at 10 Pa for 20 s to complete crystallization, and then heated at 100 °C for 10 min to form a perovskite layer. A dense tin oxide layer (with a thickness of about 50 nm) is deposited and a silver electrode is evaporated on the surface of the perovskite layer to obtain a perovskite solar cell.

[0099] Performance Test (1) The current density-voltage curves of the perovskite solar cells prepared in Examples 1 to 14 and Comparative Examples 1 to 6 were tested respectively, and the measurement results are shown in Figures 1 - 20 ; (2) The short-circuit current density (mA / cm 2 ), open-circuit voltage (V), fill factor (%), and photoelectric conversion efficiency (%) of the devices prepared in Examples 1 to 14 and Comparative Examples 1 to 7 were measured respectively, and the measurement results are shown in Table 1.

[0100] Table 1

[0101] By analyzing Table 1 and Figures 1 - 20 it can be obtained that on the current density curve, the current density corresponding to the devices of Examples 1-6 is significantly higher than that of Comparative Examples 1-5; in terms of various performances such as short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency, the mesoporous perovskite solar cells prepared in the examples are better than or not inferior to the mesoporous perovskite solar cells prepared by other methods.

[0102] In addition, by comparing Examples 7-14 with Comparative Examples 6 and 7, it can be obtained that the preparation method of the perovskite solar cells in the present invention is also applicable to the preparation of planar perovskite solar cells (thin-film perovskite solar cells) with a normal structure or an inverted structure, and is better than the perovskite solar cells with a planar or thin-film structure prepared by conventional methods in terms of relevant performance.

[0103] The above is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, The preparation method of the perovskite solar cell includes a crystallization process of a perovskite precursor solution on a substrate. The crystallization process specifically includes the following steps: S10. Provide a cavity, introduce a dry gas to clean the inside of the cavity, and keep the inside of the cavity in a dry state; S20. Place the mesoporous substrate coated with the perovskite precursor solution inside the cavity, keep the cavity in a closed state, and let it stand. The solvent in the perovskite precursor solution volatilizes into solvent vapor inside the cavity, and the concentration of the solvent vapor inside the cavity gradually increases; S30. When the solvent vapor reaches a saturated state inside the cavity, release the closed state of the cavity and dilute the solvent vapor inside the cavity; S40. When the crystallization of the perovskite precursor solution is completed, perform annealing treatment to form a perovskite layer.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step S30, diluting the solvent vapor includes: Pumping air from the cavity and maintaining the air pressure inside the cavity at (-90)~(-50) KPa, and the dilution time lasts for 0.8~2 h.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The concentration of the halide in the perovskite precursor solution is 1 to 2 M, and the dosage of the perovskite precursor solution is 2 to 3 μL / cm 2 ; and / or, the planar area of the substrate is 40 to 4000 cm 2 ; And / or, the volume of the cavity is 1~100 L; And / or, in step S40, the temperature inside the cavity during the crystallization process is 25~35 °C.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In step S40, during the annealing treatment, the annealing temperature is 80~120 °C, and the annealing time is 10~15 min.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The crystallization process of the perovskite precursor solution on the substrate specifically includes: S10. Provide a cavity, introduce a dry gas to clean the inside of the cavity, and keep the inside of the cavity in a dry state; S20. Place the substrate coated with the perovskite precursor solution inside the cavity, keep the cavity in a closed state, and let it stand. The solvent in the perovskite precursor solution volatilizes into solvent vapor inside the cavity, and the concentration of the solvent vapor inside the cavity gradually increases; S30. When the solvent vapor reaches a saturated state inside the cavity, release the closed state of the cavity and dilute the solvent vapor inside the cavity; S31. When crystallization begins to appear on the liquid film surface of the perovskite precursor solution, change the cavity to a closed state and let it stand, and the concentration of the solvent vapor inside the cavity gradually increases; S32. Sequentially repeat step S30 and step S31; S33. When the perovskite precursor solution reaches a saturated state, dilute the solvent vapor to cause the perovskite precursor solution to start crystallizing; S40. When the crystallization of the perovskite precursor solution is completed, perform annealing treatment to form a perovskite layer.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that, In step S31, when crystallization begins to appear on the surface of the perovskite precursor solution, the color or gloss of the liquid film of the perovskite precursor solution changes; And / or, in step S33, when the perovskite precursor solution reaches a saturated state, the liquid film of the precursor solution changes from a transparent state to an opaque state under the standing state, and a complex with a yellowish color appears.

7. The method for preparing a perovskite solar cell according to claim 5, characterized in that, In step S30, when diluting the solvent vapor, the dilution time is 10~60 min; And / or, in step S31, the cavity is made airtight and left standing, and the standing time is 5 to 10 minutes; And / or, in step S33, the solvent vapor is diluted, and the dilution time lasts for 0.33 to 15 hours.

8. The method for preparing a perovskite solar cell according to claim 5, characterized in that, The substrate is a mesoporous substrate; In step S30, diluting the solvent vapor includes: Evacuating the cavity and maintaining the internal air pressure of the cavity at (-90) to (-50) KPa; In step S32, steps S30 and S31 are repeated: Each time the cavity is evacuated, the negative pressure inside the cavity is gradually reduced, and the reduction amplitude is 1 to 10 KPa; In step S33, diluting the solvent vapor includes: Evacuating the cavity and maintaining the internal air pressure of the cavity at (-20) to (-10) KPa; And / or, In step S30, diluting the solvent vapor includes: Introducing dry gas into the cavity while discharging the gas inside the cavity, keeping the gas flow rates of the introduced dry gas and the discharged gas inside the cavity the same, and maintaining the gas flow rate at 10 to 100 mL / min; In step S32, steps S30 and S31 are repeated: Each time dry gas is introduced into the cavity, the gas flow rate is gradually reduced, and the reduction amplitude is 1 to 10 mL / min; In step S33, diluting the solvent vapor includes: Introducing dry gas into the cavity and maintaining the gas flow rate at 0.01 to 1 mL / min.

9. The method for preparing a perovskite solar cell according to claim 5, wherein, The substrate is a planar substrate; In step S30, diluting the solvent vapor includes: Evacuating the cavity and maintaining the internal air pressure of the cavity at (-70) to (-50) KPa; In step S32, steps S30 and S31 are repeated: Each time the cavity is evacuated, the negative pressure inside the cavity is gradually reduced, and the reduction amplitude is 1 to 10 KPa; In step S33, diluting the solvent vapor includes: Evacuating the cavity and maintaining the internal air pressure of the cavity at (-40) to (-10) KPa; And / or, In step S30, diluting the solvent vapor includes: Introducing dry gas into the cavity while discharging the gas inside the cavity, keeping the gas flow rates of the introduced dry gas and the discharged gas inside the cavity the same, and maintaining the gas flow rate at 20 to 50 mL / min; In step S32, steps S30 and S31 are repeated: Each time dry gas is introduced into the cavity, the gas flow rate is gradually reduced, and the reduction amplitude is 1 to 10 mL / min; In step S33, diluting the solvent vapor includes: Introducing dry gas into the cavity and maintaining the gas flow rate at 1 to 10 mL / min.

10. A perovskite solar cell, wherein, The perovskite solar cell is prepared by the method for preparing a perovskite solar cell according to claims 1 to 9.

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