Method for preparing perovskite thin film

Abstract

The invention provides a method for preparing a perovskite thin film, and the method comprises the steps: forming a first salt layer on one side of a substrate through first thermal evaporation treatment, and enabling the material of the first salt layer to comprise a first inorganic salt; a second salt layer is formed on the side, away from the substrate, of the first salt layer, a perovskite precursor layer is obtained, and the material of the second salt layer comprises first organic salt; carrying out annealing treatment on the perovskite precursor layer to obtain a perovskite thin film; wherein the distance between an evaporation source of the first thermal evaporation treatment and the side, facing the evaporation source, of the substrate is 2-10 cm. By means of the method, the evaporation material can be deposited on the substrate to form the thin film in a short time, loss of the evaporation material in the evaporation process is effectively reduced, and the production cost is reduced. In addition, the formed film is uniform in thickness and smooth in surface, and crystal grains grow orderly. Therefore, the finally obtained perovskite thin film is good in quality, and the solar cell is excellent in performance.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a method for preparing a perovskite film. Background Art

[0002] Perovskite solar cells have received great attention due to their excellent photovoltaic performance and have been recognized as a new thin-film photovoltaic technology with great industrial prospects. At present, the main preparation methods of perovskite thin films include spin coating, blade coating, and slit coating. There are problems such as high requirements for the rheological properties of the perovskite precursor solution, difficulty in controlling the film thickness and uniformity, the need to recover solvents, the use of organic solvents, and high costs. Therefore, it is urgent to develop a new method for preparing perovskite thin films to meet the current commercial needs. Summary of the invention

[0003] In view of the technical problems existing in the background technology, the present application provides a method for preparing a perovskite film, a solar cell, a power generation device and an electricity-using device, aiming to solve the problem of how to efficiently prepare high-quality perovskite films.

[0004] In order to achieve the above-mentioned object, the first aspect of the present application proposes a method for preparing a perovskite film, the method comprising:

[0005] Using a first thermal evaporation process to form a first salt layer on one side of the substrate, wherein the material of the first salt layer includes a first inorganic salt;

[0006] forming a second salt layer on a side of the first salt layer away from the substrate to obtain a perovskite precursor layer, wherein the material of the second salt layer includes a first organic salt;

[0007] annealing the perovskite precursor layer to obtain a perovskite film;

[0008] Wherein, the distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source is 2 cm to 10 cm.

[0009] According to the method for preparing a perovskite film according to an embodiment of the present application, a dense and uniform film can be formed by thermal evaporation, and the use of organic solvents can be avoided and solvent recovery operations can be reduced. Furthermore, the evaporation source of the first thermal evaporation treatment is set to the above-mentioned close distance with the substrate, so that the evaporation space is small, and the gas phase particles are prevented from being contaminated during the evaporation process. The gas phase can be deposited on the substrate in a relatively short time to form a thin film, effectively reducing the loss of the evaporated material during the evaporation process and reducing production costs. In addition, the film formed has a uniform thickness, a smooth surface, and orderly growth of grains. As a result, the perovskite film finally obtained is of good quality, thereby improving the performance of solar cells.

[0010] In some embodiments of the present application, the temperature of the first thermal evaporation treatment is 200° C. to 600° C.;

[0011] And / or, the first thermal evaporation treatment time is 5min to 30min;

[0012] And / or, the pressure of the first thermal evaporation treatment is not higher than 1×10 -3 Pa.

[0013] In some embodiments of the present application, the evaporation source heating rate of the first thermal evaporation process is 10° C. / s to 30° C. / s.

[0014] In some embodiments of the present application, the distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source is 2 cm to 4 cm;

[0015] and / or, the temperature of the first thermal evaporation treatment is 350° C. to 450° C.;

[0016] And / or, the first thermal evaporation treatment time is 15min to 25min;

[0017] And / or, the pressure of the first thermal evaporation treatment is 0.5×10 -3 Pa~1×10 -3 Pa;

[0018] And / or, the evaporation source heating rate of the first thermal evaporation treatment is 15°C / s to 25°C / s.

[0019] In some embodiments of the present application, the first inorganic salt includes a first cation and a first anion, the first cation includes one or more of cesium ion, potassium ion, sodium ion, rubidium ion, and methylamine ion, and the first anion includes one or more of iodide ion, bromide ion, chloride ion, and fluoride ion;

[0020] And / or, the material of the first salt layer further includes a second organic salt, the second organic salt includes a second cation and a second anion, the second cation includes one or more of formamidinium ion and methylamine ion, and the second anion includes one or more of iodide ion, bromide ion, chloride ion and fluoride ion.

[0021] In some embodiments of the present application, the second salt layer is formed by a slit coating process;

[0022] The coating rate of the slit coating process is 20 mm / s to 40 mm / s;

[0023] and / or, the injection rate of the slit coating process is 10 μL / s to 20 μL / s;

[0024] And / or, the slit width of the slit coating process is 60 μm to 80 μm.

[0025] In some embodiments of the present application, a second thermal evaporation process is used to form the second salt layer;

[0026] Wherein, the distance between the evaporation source of the second thermal evaporation treatment and the side of the first salt layer away from the substrate is 2 cm to 10 cm.

[0027] In some embodiments of the present application, the temperature of the second thermal evaporation treatment is 100° C. to 400° C.;

[0028] And / or, the second thermal evaporation treatment time is 5min to 20min;

[0029] And / or, the pressure of the second thermal evaporation treatment is not higher than 1×10 -3 Pa.

[0030] In some embodiments of the present application, the evaporation source heating rate of the second thermal evaporation process is 10° C. / s to 30° C. / s.

[0031] In some embodiments of the present application, the distance between the evaporation source of the second thermal evaporation treatment and the side of the first salt layer facing away from the substrate is 2 cm to 4 cm;

[0032] and / or, the temperature of the second thermal evaporation treatment is 150° C. to 200° C.;

[0033] And / or, the second thermal evaporation treatment time is 8min to 12min;

[0034] And / or, the pressure of the second thermal evaporation treatment is 0.5×10 -3 Pa~1×10 -3 Pa;

[0035] And / or, the evaporation source heating rate of the second thermal evaporation treatment is 15° C. / s to 20° C. / s.

[0036] In some embodiments of the present application, the first organic salt includes a third cation and a third anion, the third cation includes one or more of formamidinium ion and methylamine ion, and the third anion includes one or more of iodide ion, bromide ion, chloride ion, and fluoride ion.

[0037] In some embodiments of the present application, the thickness of the perovskite film is 10 nm to 100 μm or 400 nm to 700 nm;

[0038] And / or, the band gap of the perovskite film is 0.9 eV to 3.0 eV.

[0039] The second aspect of the present application provides a solar cell, which includes: a perovskite layer, and the perovskite layer is prepared by the method for preparing a perovskite film described in the first aspect of the present application.

[0040] The third aspect of the present application provides a power generation device, which includes: the solar cell described in the second aspect of the present application.

[0041] The fourth aspect of the present application provides an electrical device, which includes: the solar cell described in the second aspect of the present application.

[0042] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0044] Figure 1 A schematic diagram of a method for preparing a perovskite film according to an embodiment of the present application is shown;

[0045] Figure 2 A schematic diagram of the structure of a thermal evaporation system according to an embodiment of the present application is shown;

[0046] Figure 3 A schematic structural diagram of a thermal evaporation system according to another embodiment of the present application is shown.

[0047] Reference numerals:

[0048] 10: thermal evaporation system; 100: evaporation chamber; 110: substrate support component; 120: evaporation source; 200: heating device; 300: pressure regulating device. DETAILED DESCRIPTION

[0049] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0050] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0051] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 listed, and if the maximum range values ​​3,4 and 5 are listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers, and the scope limited in this way can be including end values ​​a and b. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0052] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0053] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0054] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0055] At present, the main preparation methods of perovskite films include spin coating, blade coating, and slit coating. Spin coating is generally suitable for the preparation of small-area perovskite films (large area will lead to uneven thickness at the center and edge of the film). Currently, large-area preparation of perovskite films is mainly through blade coating and slit coating. However, these two methods have high requirements on the rheological properties of the perovskite precursor solution, and there are problems such as difficult control of film thickness and uniformity, the need to recover solvents and use organic solvents, which increases production costs.

[0056] The existing method of forming thin films by thermal evaporation includes placing the substrate and the evaporation source at a long distance (e.g., greater than 50 cm) so that the evaporated material is slowly deposited on the substrate. It usually takes 40 minutes to 1 hour to form a thin film. The thermal evaporation method has a long processing time, a secondary evaporation process, poor gas phase uniformity, and serious loss of evaporated material, which increases the overall production cost.

[0057] In view of this, the present application sets the evaporation source of the first thermal evaporation treatment to be close to the substrate, so that the evaporation space is small, and the gas phase particles are prevented from being contaminated during the evaporation process. The thin film can be deposited on the substrate in a short time to form a thin film, which effectively reduces the loss of the evaporated material during the evaporation process and reduces the production cost. In addition, the formed film has a uniform thickness, a smooth surface, and orderly grain growth. As a result, the perovskite film finally obtained is of good quality, thereby improving the performance of solar cells.

[0058] Based on this, the first aspect of the present application proposes a method for preparing a perovskite film, see Figure 1 The method includes: S100 forming a first salt layer, S200 obtaining a perovskite precursor layer, and S300 obtaining a perovskite film, which will be described in detail below.

[0059] S100 forms the first salt layer

[0060] In this step, a first thermal evaporation treatment is used to form a first salt layer on one side of the substrate, wherein the material of the first salt layer includes a first inorganic salt. The thermal evaporation method can form a dense and uniform first salt layer film, and can avoid the use of organic solvents and reduce solvent recovery operations.

[0061] In the application, the term "substrate" refers to the material to be formed into the first salt layer, which may include a stacked substrate and a functional layer, the functional layer may include a charge transport layer, and the first salt layer is formed on the side of the charge transport layer away from the substrate, and the charge transport layer may be a hole transport layer or an electron transport layer. The functional layer may also include one or more of a transparent conductive layer, a passivation layer, a buffer layer, etc., which may be flexibly selected according to actual functional needs. Exemplarily, the substrate includes a substrate, a transparent conductive layer and a hole transport layer stacked in sequence, and the first salt layer is formed on the side of the hole transport layer away from the transparent conductive layer. In some embodiments, the size of the substrate does not exceed 10cm×10cm.

[0062] In some embodiments of the present application, the distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source is 2 cm to 10 cm, for example, it can be 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 8 cm, 10 cm or any two values ​​as the range value formed by the endpoint values, for example, it can be 2 cm to 4 cm. Setting the evaporation source and the substrate to the above distance can reduce the evaporation reaction space, avoid contamination of gas phase particles during the evaporation process, and form a thin film in a short time. In addition, the formed film has uniform thickness, a flat surface, and orderly growth of grains.

[0063] It should be noted that the term "the distance between the evaporation source and the side of the substrate facing the evaporation source" can be interchanged with "evaporation distance", which refers to the spatial distance between the evaporation source (i.e., the material source that is heated and generates vapor) and the substrate (i.e., the surface of the material to be coated facing the evaporation source) during vacuum evaporation coating. Exemplarily, "the distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source" refers to the average value of the distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source, specifically, it may refer to the average value of the distance between the evaporation source of the first thermal evaporation treatment and the side of the charge transport layer away from the substrate.

[0064] In some embodiments of the present application, the temperature of the first thermal evaporation treatment is 200°C to 600°C, for example, it can be 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C or any two values ​​as the range value formed by the endpoint values, illustratively, it can be 350°C to 450°C. Thus, the first salt layer material can quickly form a gas phase, so that it can be quickly and evenly deposited on the substrate, saving evaporation time and reducing production costs. The appropriate gas phase concentration in the evaporation chamber is conducive to more sufficient deposition on the substrate, reducing the loss of evaporation materials, and each functional layer on the substrate can still better maintain its original physical and chemical properties.

[0065] In some embodiments of the present application, the time of the first thermal evaporation treatment is 5 minutes to 30 minutes, for example, it can be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes or a range value formed by any two values ​​as endpoint values, for example, it can be 15 minutes to 25 minutes. Thus, rapid evaporation can be achieved, and the film thickness of the formed first salt layer is uniform, the surface is flat, and the grains grow in an orderly manner.

[0066] In some embodiments of the present application, the pressure of the first thermal evaporation process is not higher than 1×10 -3 Pa, for example, can be 1×10 -3 Pa, 0.5×10 -3 Pa, 1×10 -4 Pa, 1.5×10 -4 Pa or any two values ​​as the range value formed by the endpoint values, for example, can be 0.5×10 -3 Pa~1×10 -3 Pa. Under the above pressure, the saturated vapor pressure can be reached, so that the first salt layer material can form a gas phase more fully and quickly so as to be deposited on the substrate.

[0067] In some embodiments of the present application, the heating rate of the evaporation source in the first thermal evaporation treatment is 10°C / s to 30°C / s, for example, it can be 10°C / s, 15°C / s, 20°C / s, 25°C / s, 30°C / s or a range formed by any two values ​​as endpoint values, for example, it can be 15°C / s to 25°C / s. Thus, by rapidly heating in a short time, the evaporation time is shortened, the gas phase can be mixed evenly, and the material is easily deposited with less loss.

[0068] In some embodiments of the present application, the first inorganic salt includes a first cation and a first anion, the first cation includes one or more of cesium ion, potassium ion, sodium ion, rubidium ion, and methylamine ion, and the first anion includes one or more of iodide ion, bromide ion, chloride ion, and fluoride ion;

[0069] And / or, the material of the first salt layer further includes a second organic salt, the second organic salt includes a second cation and a second anion, the second cation includes one or more of formamidinium ion and methylamine ion, and the second anion includes one or more of iodide ion, bromide ion, chloride ion and fluoride ion.

[0070] S200 obtains the perovskite precursor layer

[0071] In this step, a second salt layer is formed on the side of the first salt layer away from the substrate to obtain a perovskite precursor layer, wherein the material of the second salt layer includes a first organic salt. The material of the first salt layer reacts with the material of the second salt layer to form a perovskite precursor.

[0072] In some embodiments of the present application, the second salt layer is formed by slit coating. Since the slit coating process has high requirements on the rheological properties of the solution, the rheological properties of the organic salt solution are more suitable for slit coating process than those of the inorganic salt solution. The slit coating process can achieve a fast and uniform film coating process, reduce defects in the coating process, and improve the overall quality of the film.

[0073] In some embodiments of the present application, the coating rate of the slit coating process is 20mm / s to 40mm / s, for example, it can be 20mm / s, 25mm / s, 30mm / s, 35mm / s, 40mm / s or any two values ​​as the range value formed by the endpoint values. In other embodiments of the present application, the injection volume of the slit coating process is 10μL / s to 20μL / s, for example, it can be 10μL / s, 12μL / s, 13μL / s, 14μL / s, 15μL / s, 16μL / s, 18μL / s, 20μL / s or any two values ​​as the range value formed by the endpoint values. In some other embodiments of the present application, the slit width of the slit coating process is 60μm to 80μm, for example, it can be 60μm, 65μm, 70μm, 75μm, 80μm or any two values ​​as the range value formed by the endpoint values. Thus, the second salt can be uniformly formed on the surface of the first salt layer and can effectively penetrate into the deep layer of the film, thereby forming a uniform perovskite film.

[0074] In some embodiments of the present application, the second salt layer is formed by a second thermal evaporation process. The thermal evaporation method can form a dense and uniform film, avoid the use of organic solvents, and reduce solvent recovery operations.

[0075] In some embodiments of the present application, the distance between the evaporation source of the second thermal evaporation treatment and the side of the first salt layer away from the substrate is 2cm to 10cm, that is, the distance between the evaporation source of the second thermal evaporation treatment and the surface of the layer to be formed as the second salt layer is 2cm to 10cm, for example, it can be 2cm, 3cm, 4cm, 5cm, 6cm, 8cm, 10cm or any two values ​​as the range value formed by the endpoint value, illustratively, it can be 2cm to 4cm. Setting the evaporation source and the substrate to the above distance can reduce the evaporation reaction space, avoid contamination of gas phase particles during the evaporation process, and the gas phase can be deposited on the substrate in a shorter time to form a thin film, effectively reducing the loss of evaporation materials during the evaporation process and reducing production costs. In addition, the formed film has uniform thickness, a smooth surface, and orderly growth of grains. As a result, the perovskite film finally obtained is of good quality, thereby improving the performance of solar cells.

[0076] In some embodiments of the present application, the temperature of the second thermal evaporation treatment is 100°C to 400°C, for example, it can be 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C or any two values ​​as the range value formed by the endpoint values, illustratively, it can be 150°C to 200°C. Thus, the second salt layer material can quickly form a gas phase, so that it can be quickly and evenly deposited on the substrate, saving evaporation time and reducing production costs. The appropriate gas phase concentration in the evaporation chamber is conducive to more sufficient deposition on the substrate, reducing the loss of evaporation materials, and each functional layer on the substrate can still better maintain its original physical and chemical properties.

[0077] In some embodiments of the present application, the second thermal evaporation treatment time is 5 min to 20 min, for example, it can be 5 min, 8 min, 10 min, 12 min, 15 min, 18 min, 20 min or a range value formed by any two values ​​as endpoint values, for example, it can be 8 min to 12 min. Thus, rapid evaporation can be achieved, and the film thickness of the formed second salt layer is uniform, the surface is flat, and the grains grow in an orderly manner.

[0078] In some embodiments of the present application, the pressure of the second thermal evaporation process is not higher than 1×10 -3 Pa, for example, can be 1×10 -3 Pa, 0.5×10 -3 Pa, 1×10 -4 Pa, 1.5×10 -4 Pa or any two values ​​as the range value formed by the endpoint values, for example, can be 0.5×10 -3 Pa~1×10 -3Pa. Under the above pressure, the saturated vapor pressure can be reached, so that the second salt layer material can form a gas phase more fully and quickly so as to be deposited on the first salt layer.

[0079] In some embodiments of the present application, the heating rate of the evaporation source of the second thermal evaporation treatment is 10°C / s to 30°C / s, for example, it can be 10°C / s, 15°C / s, 20°C / s, 25°C / s, 30°C / s or a range formed by any two values ​​as endpoint values, for example, it can be 15°C / s to 25°C / s. Thus, by rapidly heating in a short time, the evaporation time is shortened, the gas phase can be mixed evenly, and the material is easily deposited with less loss.

[0080] In some embodiments of the present application, the first organic salt includes a third cation and a third anion, the third cation includes one or more of formamidinium ion and methylamine ion, and the third anion includes one or more of iodide ion, bromide ion, chloride ion, and fluoride ion.

[0081] S300 obtains perovskite film

[0082] In this step, the perovskite precursor layer is annealed to obtain a perovskite film. The annealing process can promote the transformation of the perovskite precursor to the perovskite phase and form high-quality perovskite crystals.

[0083] The present application does not specifically limit the annealing treatment method, and either conventional thermal annealing, physical annealing or chemical annealing may be used. Physical annealing may include the use of electromagnetic waves, thermal energy, etc., while chemical annealing may include the use of specific solvents or extractants to promote crystallization.

[0084] In one embodiment of the present application, the thickness of the perovskite film is 10 nm to 100 μm or 400 nm to 700 nm, for example, 400 nm, 500 nm, 600 nm, 700 nm or a range formed by any two values ​​as endpoints. Thus, the quality of the perovskite film is better.

[0085] In one embodiment of the present application, the band gap of the perovskite film is 0.9 eV to 3.0 eV, for example, it can be 0.9 eV, 1.0 eV, 1.5 eV, 2.0 eV, 2.5 eV, 3.0 eV or a range formed by any two values ​​as endpoint values. Thus, a perovskite film with different functions can be obtained.

[0086] For ease of understanding, the following briefly describes a system for implementing the first thermal evaporation process and / or the second thermal evaporation process of the present application. Figure 2 , the system 10 comprises:

[0087] An evaporation chamber 100 is provided with a substrate support component 110 and an evaporation source 120; the substrate support component 110 is used to support the material to be evaporated, which may be a substrate to form a first salt layer or a substrate to form a second salt layer; the evaporation source 120 is used to accommodate the evaporated material;

[0088] The heating device 200 is used to heat the evaporation chamber 100 .

[0089] In some embodiments of the present application, the system 10 further comprises: a pressure regulating device 300, wherein the pressure regulating device 300 is used to regulate the pressure in the evaporation chamber 100. Thus, the pressure in the evaporation chamber can be no higher than 1×10 -3 Pa. Exemplarily, the pressure regulating device may be a pressure pump.

[0090] In some embodiments of the present application, the evaporation chamber 100 may be formed by a glass tubular device.

[0091] In some embodiments of the present application, the system 10 further includes: a position adjustment component (not shown in the figure), which is connected to the substrate support component 110 and is used to adjust the distance between the substrate support component 110 and the evaporation source 120.

[0092] In some embodiments of the present application, the substrate support component 110 is selected from a crucible. The crucible has good thermal conductivity and moisture retention, which is conducive to the rapid formation of a gas phase by the evaporation material contained therein, and is conducive to deposition. Exemplarily, the substrate support component can be fixed to the inner walls of both sides of the crucible tank by a position adjustment component.

[0093] The second aspect of the present application provides a solar cell, the solar cell comprising: a perovskite layer, the perovskite layer is prepared by the method for preparing a perovskite film described in the first aspect of the present application. As a result, the solar cell of the present application has excellent photoelectric performance, repeatability and stability. The solar cell has all the features and advantages of the aforementioned method for preparing a perovskite film, which will not be repeated here.

[0094] The third aspect of the present application provides a power generation device, the power generation device comprising: the solar cell described in the second aspect of the present application. Therefore, the light emitting device of the present application has excellent photoelectric performance, repeatability and stability.

[0095] In this application, the power generation device refers to a power generation system that uses the photovoltaic effect to directly convert solar radiation energy into electrical energy, which is divided into a stand-alone photovoltaic power generation system (Stand-alone PV System) and a grid-connected photovoltaic power generation system (Grid-connected PV System). The stand-alone photovoltaic power generation system consists of a solar photovoltaic array composed of photovoltaic components, a battery pack, a charge controller, a power electronic converter (inverter), a load, etc. The grid-connected photovoltaic power generation system consists of a photovoltaic array, a high-frequency DC / DC boost circuit, a power electronic converter (inverter) and a system monitoring part.

[0096] The fourth aspect of the present application provides an electrical device, the electrical device comprising: the solar cell according to the second aspect of the present application. Therefore, the electrical device of the present application has excellent photoelectric performance, repeatability and stability.

[0097] In the present application, electrical devices may include lighting elements, display elements, mobile devices, etc., and may specifically include street lights, signal indicators, insect killer lamps, electric fans, electric toys, electric tools, battery vehicles, electric vehicles, ships, spacecraft, etc., among which electric toys may include fixed or mobile electric toys, for example, game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles and spacecraft, etc.; photovoltaic power generation systems may include large-scale ground photovoltaic power generation systems, distributed photovoltaic power generation and building integrated photovoltaic power generation systems, etc.

[0098] It should be noted that the features and advantages described above for the method for preparing perovskite thin film in the first aspect of the present application are also applicable to the solar cell described in the second aspect, the power generation device described in the third aspect and the power consumption device described in the fourth aspect of the present application, and will not be repeated here.

[0099] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0100] In the following embodiments, Figure 3 The thermal evaporation system shown performs a thermal evaporation process.

[0101] Example 1

[0102] In this embodiment, a solar cell is prepared according to the following method:

[0103] 1. Provide transparent glass with a thickness of 3mm;

[0104] 2. FTO is formed on transparent glass by magnetron sputtering with a thickness of 200 nm;

[0105] 3. Forming NiO hole transport layer on FTO by magnetron sputtering X , thickness is 20nm;

[0106] 4. Use rapid thermal evaporation (using Figure 3 The PbI2 film was formed on the hole transport layer by the thermal evaporation system shown in the figure. The thickness of the film was 450 nm. The distance between the evaporation source and the hole transport layer was 3 cm. The evaporation temperature was 400 °C, the time was 20 min, and the pressure was 6 × 10 -4 Pa, the evaporation source heating rate is 20℃ / s, and the implementation system is shown in Figure 2 ;

[0107] 5. An organic salt solution (containing 8 mg / mL CsI, 7 mg / mL LMAI, 18 mg / mL FAI, and 10 mg / mL MACl) was coated on the slit of the PbI2 film to form an organic salt layer. The coating rate was 30 mm / s, the injection volume was 18 μL / s, and the slit width was 70 μm. Then, the film was annealed at 150 °C for 15 min to obtain a perovskite film with a thickness of about 500 nm.

[0108] 6. Thermal evaporation of C on perovskite films 60 , thickness is 25nm;

[0109] 7. Use thermal evaporation at C 60 Bathcopper(BCP) is formed on the surface with a thickness of 5 nm;

[0110] 8. Cu is formed on the BCP by thermal evaporation with a thickness of 90 nm to obtain a solar cell.

[0111] Example 2

[0112] A solar cell was prepared according to the method of Example 1, except that in step 4, the distance between the evaporation source and the hole transport layer was 10 cm.

[0113] Example 3

[0114] A solar cell was prepared according to the method of Example 1, except that in step 4, the distance between the evaporation source and the hole transport layer was 2 cm.

[0115] Example 4

[0116] A solar cell is prepared according to the method of Example 1, except that step 5 is as follows:

[0117] Rapid thermal evaporation (using Figure 3The thermal evaporation system shown in the figure was implemented) organic salt (containing 8 mg / mL CsI, 7 mg / mL LMAI, 18 mg / mL FAI, and 10 mg / mL MACl) to obtain a perovskite film with a thickness of 500 nm. The distance between the evaporation source and the PbI2 film was 3 cm, the evaporation temperature was 180 °C, the time was 10 min, and the pressure was 6×10 -4 Pa, and the evaporation source heating rate is 15℃ / s.

[0118] Example 5

[0119] A solar cell was prepared according to the method of Example 1, except that in step 4, the temperature of thermal evaporation was 100°C.

[0120] Example 6

[0121] A solar cell was prepared according to the method of Example 1, except that in step 4, the temperature of thermal evaporation was 700°C.

[0122] Example 7

[0123] A solar cell was prepared according to the method of Example 1, except that in step 4, the thermal evaporation time was 4 minutes.

[0124] Example 8

[0125] A solar cell was prepared according to the method of Example 1, except that in step 4, the thermal evaporation time was 40 minutes.

[0126] Example 9

[0127] A solar cell was prepared according to the method of Example 1, except that in step 4, the heating rate of the evaporation source was 5° C. / s.

[0128] Example 10

[0129] A solar cell was prepared according to the method of Example 1, except that in step 4, the heating rate of the evaporation source was 40° C. / s.

[0130] Comparative Example 1

[0131] A solar cell was prepared according to the method of Example 1, except that in step 4, a PbI2 thin film was formed on the hole transport layer by slit coating, the coating rate was 30 mm / s, the injection volume was 18 μL / s, and the slit width was 70 μm.

[0132] Comparative Example 2

[0133] A solar cell was prepared according to the method of Example 1, except that the distance between the evaporation source and the hole transport layer was 15 cm.

[0134] Comparative Example 3

[0135] A solar cell was prepared according to the method of Example 1, except that the distance between the evaporation source and the hole transport layer was 1 cm.

[0136] Test Case

[0137] The performance tests were performed on the solar cells prepared in the above-mentioned Examples 1 to 10 and Comparative Examples 1 to 3 respectively.

[0138] The specific test method is: place the prepared battery device under a light source with an intensity P of 100mW / cm 2 The AM1.5G standard simulates sunlight. By changing the bias voltage of the load on the battery device, the current value of the battery device is obtained, thereby drawing the current density (J)-voltage (V) curve of the battery device, and thus obtaining the open circuit voltage Voc, short circuit current density Jsc, fill factor FF, and photoelectric conversion efficiency of the battery device, that is, battery efficiency PCE: V and J of the battery device change with the change of external load. When the external load is short-circuited, V=0, and J at this time is called short-circuit current density Jsc; when the external load is disconnected, J=0, and V at this time is called open circuit voltage Voc; the output power of the battery device has a maximum value, which is called the maximum power point Pmax, Pmax divided by the effective light-receiving area of ​​the battery device, that is, the battery efficiency PCE; the fill factor FF of the battery device is PCE×P / (Jsc×Voc).

[0139] Table 1 Performance parameters of different solar cells

[0140] Examples <![CDATA[Jsc(mA / cm 2 )]]> Voc(V) PCE(%) FF(%) Example 1 22.83 1.00 16.98 74.36 Example 2 22.11 1.01 16.55 74.11 Example 3 22.36 1.01 16.78 74.29 Example 4 22.81 1.01 17.32 75.17 Example 5 22.17 1.00 16.47 74.31 Example 6 22.05 1.02 16.22 72.11 Example 7 22.31 1.00 16.09 72.12 Example 8 21.61 0.99 15.69 73.32 Example 9 22.23 1.01 16.06 71.51 Example 10 22.58 1.00 15.88 70.32 Comparative Example 1 21.32 0.99 14.43 68.37 Comparative Example 2 22.37 1.00 15.56 69.55 Comparative Example 3 21.58 0.99 14.86 69.57

[0141] As can be seen from Table 1, the performance of the solar cells prepared in Examples 1 to 10 is better than that of the solar cells prepared in Comparative Examples 1 to 3. This shows that by adopting the thermal evaporation method and setting the evaporation source of the first thermal evaporation treatment at a close distance to the substrate, the evaporation space is small, and the gas phase particles are prevented from being contaminated during the evaporation process. The particles can be deposited on the substrate in a shorter time to form a thin film, which effectively reduces the loss of the evaporated material during the evaporation process and reduces the production cost. In addition, the formed film has a uniform thickness, a smooth surface, and orderly grain growth. As a result, the perovskite film finally obtained is of good quality, thereby improving the performance of the solar cell.

[0142] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a perovskite film, characterized in that: include: Using a first thermal evaporation process to form a first salt layer on one side of the substrate, wherein the material of the first salt layer includes a first inorganic salt; forming a second salt layer on a side of the first salt layer away from the substrate to obtain a perovskite precursor layer, wherein the material of the second salt layer includes a first organic salt; annealing the perovskite precursor layer to obtain a perovskite film; Wherein, the distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source is 2 cm to 10 cm.

2. The method according to claim 1, characterized in that The temperature of the first thermal evaporation treatment is 200°C to 600°C; And / or, the first thermal evaporation treatment time is 5min to 30min; And / or, the pressure of the first thermal evaporation treatment is not higher than 1×10 -3 Pa.

3. The method according to claim 1, characterized in that The evaporation source temperature rise rate of the first thermal evaporation treatment is 10° C. / s to 30° C. / s.

4. The method according to claim 1, characterized in that: The distance between the evaporation source of the first thermal evaporation treatment and the side of the substrate facing the evaporation source is 2 cm to 4 cm; and / or, the temperature of the first thermal evaporation treatment is 350° C. to 450° C.; And / or, the first thermal evaporation treatment time is 15min to 25min; And / or, the pressure of the first thermal evaporation treatment is 0.5×10 -3 Pa~1×10 -3 Pa; And / or, the evaporation source heating rate of the first thermal evaporation treatment is 15°C / s to 25°C / s.

5. The method according to claim 1, characterized in that The first inorganic salt includes a first cation and a first anion, wherein the first cation includes one or more of cesium ion, potassium ion, sodium ion, rubidium ion, and methylamine ion, and the first anion includes one or more of iodide ion, bromide ion, chloride ion, and fluoride ion; And / or, the material of the first salt layer further includes a second organic salt, the second organic salt includes a second cation and a second anion, the second cation includes one or more of formamidinium ion and methylamine ion, and the second anion includes one or more of iodide ion, bromide ion, chloride ion and fluoride ion.

6. The method according to claim 1, characterized in that forming the second salt layer by slit coating process; The coating rate of the slit coating process is 20 mm / s to 40 mm / s; and / or, the injection rate of the slit coating process is 10 μL / s to 20 μL / s; And / or, the slit width of the slit coating process is 60 μm to 80 μm.

7. The method according to claim 1, characterized in that forming the second salt layer by a second thermal evaporation process; Wherein, the distance between the evaporation source of the second thermal evaporation treatment and the side of the first salt layer away from the substrate is 2 cm to 10 cm.

8. The method according to claim 7, characterized in that The temperature of the second thermal evaporation treatment is 100°C to 400°C; And / or, the second thermal evaporation treatment time is 5min to 20min; And / or, the pressure of the second thermal evaporation treatment is not higher than 1×10 -3 Pa.

9. The method according to claim 7, characterized in that: The heating rate of the evaporation source in the second thermal evaporation process is 10° C. / s to 30° C. / s.

10. The method according to claim 7, characterized in that The distance between the evaporation source of the second thermal evaporation treatment and the side of the first salt layer away from the substrate is 2 cm to 4 cm; and / or, the temperature of the second thermal evaporation treatment is 150° C. to 200° C.; And / or, the second thermal evaporation treatment time is 8min to 12min; And / or, the pressure of the second thermal evaporation treatment is 0.5×10 -3 Pa~1×10 -3 Pa; And / or, the evaporation source heating rate of the second thermal evaporation treatment is 15° C. / s to 20° C. / s.

11. The method according to claim 1, characterized in that: The first organic salt includes a third cation and a third anion, wherein the third cation includes one or more of formamidinium ion and methylamine ion, and the third anion includes one or more of iodide ion, bromide ion, chloride ion and fluoride ion.

12. The method according to claim 1, characterized in that The thickness of the perovskite film is 10nm to 100μm or 400nm to 700nm; And / or, the band gap of the perovskite film is 0.9 eV to 3.0 eV.

13. A solar cell, characterized in that: The invention comprises: a perovskite layer, wherein the perovskite layer is prepared by the method for preparing a perovskite film according to any one of claims 1 to 12.

14. A power generation device, characterized in that: include: The solar cell according to claim 13.

15. An electrical device, characterized in that: include: The solar cell according to claim 13.

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