Perovskite film preparation device, preparation method and perovskite battery

Abstract

The present invention provides a perovskite thin film preparation device, preparation method, and perovskite battery. The perovskite thin film preparation device includes a vacuum film forming system and an MFC gas flow control system, wherein the air inlet of the vacuum film forming system is connected to the MFC gas flow control system; the vacuum film forming system includes a vacuum unit and an evacuation unit, wherein the vacuum unit includes a vacuum chamber, and the air outlet of the vacuum chamber is connected to the evacuation unit. By adding an MFC gas flow control system to the equipment and modifying it, the present invention can effectively control the composition and quantity of residual gas molecules within the equipment, thereby producing a loose and porous metal halide film without affecting the purity of the film. This facilitates the subsequent infiltration of organic components, enhances the nucleation and crystallization of the perovskite, and produces high-quality, large-area perovskite films and devices with excellent performance. The equipment has a simple structure and highly stable process parameters, making it suitable for large-scale application and mass production.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and in particular relates to a perovskite thin film preparation device, a preparation method and a perovskite cell. Background Art

[0002] Perovskite, named after the Russian mineralogist Perovskite, is a general term for crystals with an ABX3 structure and similar structures. They are currently widely used in ultrasonic devices, memory chips, and solar cells. Perovskite solar cells utilize perovskite-structured materials as light-absorbing materials. They boast high efficiency, low cost, and flexibility, and have enormous potential for future development. In 2009, the efficiency of perovskite solar cells was only 3.8%. Currently, the highest efficiency of certified single-junction cells is 25.7%, and the highest efficiency of perovskite / silicon tandem cells is 32.5%. In just a few decades, these cells have surpassed the efficiency limits of other types of solar cells and hold great promise for application in fields such as BIPV, automotive photovoltaics, indoor photovoltaics, and ground-based power stations.

[0003] The current methods for preparing perovskite films can be roughly divided into solution method and vacuum method.

[0004] The solution method generally prepares a wet film by spin coating, doctor blade coating, spray coating or slot die coating, and then forms a perovskite film by annealing. It is the most widely used method for preparing a perovskite light-absorbing layer. However, current high-performance devices are all based on laboratory-level spin coating and anti-solvent-assisted methods. In addition, the use of the solution method to prepare perovskite films has extremely high requirements for the flatness of the substrate, because the thickness of the perovskite film prepared by the solution method is usually only a few hundred nanometers. If the substrate is uneven, the prepared film will not be able to completely cover the substrate, and the prepared film uniformity is poor. In addition, the evaporation time of the solvent used in the solution method is difficult to grasp, and it is easy to form pinhole defects in the perovskite film, affecting the efficiency of the battery device. In addition, some special solvents and a large amount of counter-reagents used in the solution method do not meet the standards of industrial production and cannot meet the requirements of large-scale preparation.

[0005] The vacuum deposition method involves depositing perovskite precursor materials directly onto a substrate via physical vapor deposition (PVD) or chemical vapor deposition (CVD) in a vacuum environment, either through a one-step co-evaporation or sequential evaporation process. Annealing is then performed to promote crystallization and form a perovskite film. The advantage of vacuum deposition of perovskite thin films is that the flatness of the substrate is not a concern; vacuum deposition can completely cover the substrate surface, forming a continuous film. In conventional methods such as vacuum evaporation, close-space sublimation (CSS), ion sputtering, or vapor transport deposition (VTD), particles evaporated from the material surface move linearly within the deposition chamber at a constant velocity and ultimately deposit on the substrate surface to form a thin film. During the deposition process, residual gases in the vacuum chamber impinge on all surfaces within the chamber, including the growing film, significantly impacting the film. These gas molecules primarily originate from desorption and outgassing on the chamber surfaces, evaporation sources, including gases released by the evaporated material, backflow from the exhaust system, and equipment leaks.

[0006] Therefore, in order to obtain a film layer with good purity, vacuum equipment needs to achieve a high vacuum state through the vacuum system to minimize the residual gas molecules in the vacuum chamber. However, high vacuum will also reduce the collision between the evaporation material molecules and the residual gas molecules, increase the mean free path, and make the prepared film denser. The film layer is not loose enough, which hinders the penetration of the organic components in the second step, resulting in incomplete reaction and the problem of metal halide residue. Therefore, high purity and loose porosity are necessary conditions for the first step of the perovskite two-step method to produce high-quality metal halide films. To a certain extent, they cannot be achieved simultaneously. Therefore, the disadvantage of the current technology is that it is impossible to prepare large-area, high-purity, loose and porous metal halide films with simple processes through the vacuum method, resulting in the problem of metal halide residue in the generated perovskite film.

[0007] Therefore, how to prepare high-purity, loose and porous metal halide films through a vacuum method to avoid the problem of metal halide residues in the generated perovskite films, thereby preparing high-quality and large-area perovskite films, is a technical problem that needs to be solved urgently. Summary of the Invention

[0008] In response to the shortcomings of the prior art, the present invention aims to provide a perovskite thin film preparation device, preparation method, and perovskite battery. By modifying the device by adding an MFC gas flow control system, the present invention effectively controls the composition and quantity of residual gas molecules within the device, keeping their impact on the molecules of the evaporated material within a controllable range. This allows the preparation of a loose and porous metal halide film without affecting the purity of the film, which facilitates the infiltration of organic components in the second step and enhances the nucleation and crystallization of the perovskite. Furthermore, the device can modify the film using different gases within a vacuum chamber, controlling the film morphology, thereby producing high-quality, large-area perovskite films and excellent-performance battery devices. The device has a simple structure and highly stable process parameters, making it suitable for large-scale applications and mass production.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a perovskite thin film preparation device, the perovskite thin film preparation device comprising a vacuum film forming system and an MFC gas flow control system, wherein the air inlet of the vacuum film forming system is connected to the MFC gas flow control system;

[0011] The vacuum film forming system includes a vacuum unit and a vacuum pumping unit. The vacuum unit includes a vacuum chamber. The air outlet of the vacuum chamber is connected to the vacuum pumping unit.

[0012] The vacuum chamber is adjusted to a high vacuum state using a vacuum pump. This is done to remove any residual gas molecules in the coating environment to minimize adverse effects. This is because active molecules in the air may react with the film or evaporating material to form compounds. Residual gas molecules enter the film and form impurities, affecting film purity. Excessive gas molecules can hinder the straight-line movement of the atoms and molecules of the evaporating material, preventing many vapor molecules from reaching the substrate and forming a continuous film on the substrate. However, high vacuum also reduces collisions between evaporating material molecules and residual gas molecules, increasing the mean free path and making the prepared film denser. This makes the film less porous, hindering the penetration of organic components in the second step, resulting in incomplete reaction and the potential for residual metal halides.

[0013] Therefore, by adding an MFC gas flow control system to the air inlet of the vacuum film forming system, the present invention ensures that the vacuum level is controlled within the desired range. Within this range, the mean free path of the evaporating material molecules and the working gas molecules is shortened, and the kinetic energy of both the material molecules and the gas molecules reaching the substrate is reduced. This effectively controls the composition and quantity of the residual gas molecules within the device, keeping their impact on the evaporating material molecules within a controllable range. This allows the production of a loose and porous metal halide film without affecting the film's purity. This facilitates the infiltration of the organic salt solution in the second step, enhancing the nucleation and crystallization of the perovskite. Furthermore, the device can utilize different gases to modify the film within the vacuum chamber, controlling the film morphology, thereby producing high-quality, large-area perovskite films and excellent-performance battery devices. The device has a simple structure and highly stable process parameters, making it suitable for large-scale applications and mass production.

[0014] In the present invention, the choice of vacuum film forming system is not limited. For example, it can be a vacuum evaporation device, an ion sputtering device, a vacuum evaporation device for close space sublimation, or a vacuum evaporation device used in vapor transport method (VTD).

[0015] As a preferred technical solution of the present invention, the MFC gas flow control system includes an intake source, a solenoid valve, an MFC controller and a main intake valve connected in sequence along the intake direction.

[0016] In the present invention, there is no limitation on the air intake source, and for example, it may be a cylinder or a pipeline.

[0017] In the present invention, the solenoid valve can control the introduction of gas, the MFC controller can adjust the flow rate of the introduced gas, and the main air inlet valve is the switch for the gas to enter the vacuum unit.

[0018] Preferably, a pressure reducing valve is provided between the solenoid valve and the MFC controller.

[0019] In the present invention, the pressure reducing valve can help the introduced gas to maintain a suitable and stable pressure range.

[0020] As a preferred technical solution of the present invention, the vacuum unit includes a molecular pump and a mechanical pump connected in sequence along the direction of gas outlet.

[0021] Preferably, the gas outlet of the vacuum chamber includes a first gas outlet and a second gas outlet, and a gate valve is provided between the molecular pump and the first gas outlet.

[0022] In the present invention, the gate valve is used to open and close the molecular pump and the first gas outlet of the vacuum chamber.

[0023] Preferably, a front-stage valve is provided between the molecular pump and the mechanical pump.

[0024] Preferably, a pre-pumping valve is provided between the mechanical pump and the second air outlet of the vacuum chamber.

[0025] In a second aspect, the present invention provides a method for preparing a perovskite film, wherein the method uses the perovskite film preparation device described in the first aspect;

[0026] The preparation method comprises the following steps:

[0027] (1) placing the substrate in a vacuum chamber and evacuating the chamber using a vacuum pumping unit;

[0028] (2) introducing working gas through the MFC gas flow control system;

[0029] (3) vacuum depositing the raw materials on the surface of the substrate to form a metal halide film;

[0030] (4) An organic halide film is prepared on the surface of the metal halide film, and the perovskite film is obtained by heat treatment.

[0031] The present invention introduces a constant flow of working gas under vacuum conditions to ensure that the vacuum level is controlled within a desired range. Within this range, the mean free path of the evaporated material molecules and the working gas molecules is shortened, and the kinetic energy of both the material and gas molecules reaching the substrate is reduced. This preparation method can effectively produce loose and porous metal halide films, further facilitating the reaction between the metal halide film and the organic salt, thereby resolving the problem of metal halide residues in films prepared by conventional vacuum methods and facilitating the production of higher-quality perovskite films.

[0032] The present invention does not limit the substrate, which can be FTO conductive glass, ITO conductive glass, or conductive glass coated with a hole transport layer or an electron transport layer.

[0033] As a preferred technical solution of the present invention, after the vacuuming is performed by the vacuuming unit in step (1), the vacuum degree in the vacuum chamber is less than or equal to 1×10 -5 Pa, for example, can be 1×10 -5 , 8×10 -6 Pa, 6×10 -6 Pa, 4×10 -6 Pa, 2×10 -6 Pa or 1×10 -6 Pa et al.

[0034] Preferably, the working gas in step (2) comprises any one of oxygen, nitrogen, inert gas or cesium halide gas, or a combination of at least two of them.

[0035] Preferably, the inert gas includes any one of argon, helium, neon or xenon, or a combination of at least two of them.

[0036] Preferably, the cesium halide gas includes any one of cesium iodide gas, cesium chloride gas or cesium bromide gas, or a combination of at least two of them.

[0037] Preferably, the gas flow rate of the working gas in step (2) is 0-50sccm, excluding 0, for example, it can be 5sccm, 10sccm, 15sccm, 20sccm, 25sccm, 30sccm, 35sccm, 40sccm, 45sccm or 50sccm, etc., preferably 5-30sccm.

[0038] In the present invention, if the flow rate of the working gas is too large, the vacuum level of the chamber will be too low, making it difficult to form a continuous and uniform thin film.

[0039] Preferably, after the working gas is introduced in step (2), the vacuum degree in the vacuum chamber is stabilized at 1×10 -4 -1×10 -2 Pa, for example, it can be 1×10 -4 Pa, 2×10 -3 Pa, 4×10 -3 Pa, 6×10 -3 Pa, 8×10 -3 Pa or 1×10 -2 Pa et al.

[0040] In the present invention, if the vacuum degree in the vacuum chamber is too small after the working gas is introduced, that is, the vacuum degree is too high, then the looseness of the film will be less affected; if the vacuum degree in the vacuum chamber is too large after the working gas is introduced, that is, the vacuum degree is too low, then it will be difficult to form a continuous and uniform film.

[0041] As a preferred technical solution of the present invention, the raw materials in step (3) include lead halide and / or rubidium halide.

[0042] Preferably, the lead halide includes any one of lead iodide, lead chloride or lead bromide, or a combination of at least two of them.

[0043] Preferably, the rubidium halide includes any one of rubidium iodide, rubidium chloride or rubidium bromide, or a combination of at least two of them.

[0044] Preferably, the raw material in step (3) further comprises cesium halide.

[0045] Preferably, the cesium halide includes any one of cesium iodide, cesium chloride or cesium bromide, or a combination of at least two thereof.

[0046] As a preferred technical solution of the present invention, the deposition rate of the vacuum deposition in step (3) is 0.1-20A / s, for example, it can be 0.1A / s, 1A / s, 5A / s, 10A / s, 15A / s or 20A / s, etc., preferably 1-5A / s.

[0047] Preferably, during the vacuum deposition process in step (3), the temperature of the evaporation source is 200-400°C, for example, it can be 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 320°C, 340°C, 360°C, 380°C or 400°C.

[0048] Preferably, the thickness of the metal halide film in step (3) is 100-800 nm, for example, it can be 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm or 800 nm, and is preferably 300-500 nm.

[0049] As a preferred technical solution of the present invention, the method for preparing the organic halide film in step (4) includes a solution method or a vacuum method.

[0050] Preferably, in the process of preparing the organic halide film by the solution method, the solute in the organic halide solution used includes formamidinium halide and / or methylamino halide.

[0051] Preferably, the formamidine halide comprises any one of iodoformamidine, bromoformamidine or chloroformamidine, or a combination of at least two thereof.

[0052] Preferably, the methylamino halide comprises any one of iodomethylamine, bromomethylamine or chloromethylamine, or a combination of at least two thereof.

[0053] Preferably, the concentration of the organic halide solution is 0.1-1.5 mol / L, for example, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.7 mol / L, 0.9 mol / L, 1.2 mol / L or 1.5 mol / L.

[0054] Preferably, in the vacuum method, the cations of the raw materials of the organic halide film include methylamine cations and / or formamidine cations, and the anions of the raw materials of the organic halide film include any one of iodide ions, bromide ions, and chloride ions, or a combination of at least two of them.

[0055] In the present invention, the solution method is not specifically limited. For example, it can be wire rod coating, slit coating, spray coating, spin coating or immersion. The equipment used in the vacuum method is not specifically limited. For example, it can be evaporation equipment, ion sputtering equipment, close space sublimation equipment, vapor transport deposition (VTD) equipment, etc. As a preferred technical solution of the present invention, the heat treatment method in step (4) includes direct annealing or step annealing.

[0056] Preferably, the direct annealing temperature is 100-500°C, for example, 100°C, 200°C, 300°C, 400°C or 500°C, and the time is 1-30 min, for example, 1 min, 5 min, 10 min, 15 min, 20 min, 25 min or 30 min.

[0057] Preferably, the step annealing includes primary annealing and secondary annealing.

[0058] Preferably, the primary annealing temperature is 25-100°C, for example, 25°C, 50°C, 75°C or 100°C, and the time is 1-30 min, for example, 1 min, 5 min, 10 min, 15 min, 20 min, 25 min or 30 min.

[0059] Preferably, the secondary annealing temperature is 100-500°C, for example, 100°C, 200°C, 300°C, 400°C or 500°C, and the time is 1-30 min, for example, 1 min, 5 min, 10 min, 15 min, 20 min, 25 min or 30 min.

[0060] In a third aspect, the present invention provides a perovskite film, which is prepared using the preparation method described in the second aspect, or prepared using the perovskite film preparation equipment described in the first aspect.

[0061] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] (1) By modifying the equipment by adding an MFC gas flow control system, the present invention can effectively control the composition and quantity of residual gas molecules within the equipment, keeping their impact on the molecules of the evaporated material within a controllable range. This allows the production of a loose and porous metal halide film without affecting the purity of the film. This facilitates the infiltration of organic components in the second step and increases the nucleation and crystallization of the perovskite. Furthermore, the device can modify the film using different gases within the vacuum chamber, controlling the film morphology, thereby producing high-quality, large-area perovskite films and excellent battery devices.

[0064] (2) The preparation equipment designed in the present invention has a simple structure and high process parameter stability, and is suitable for large-scale application and batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 Schematic diagram of a perovskite thin film preparation device provided in one specific embodiment of the present invention.

[0066] Among them, 1-vacuum film forming system, 2-MFC gas flow control system, 3-vacuum unit, 4-vacuum pumping unit, 5-air inlet, 6-air outlet, 7-air inlet source, 8-solenoid valve, 9-pressure reducing valve, 10-MFC controller, 11-main air inlet valve, 12-vacuum chamber, 13-mechanical pump, 14-fore valve, 15-molecular pump, 16-gate valve, 17-pre-pumping valve, 18-first air outlet, 19-second air outlet.

[0067] Figure 2 This is a scanning electron microscope image of the lead iodide thin film prepared in Example 2 of the present invention.

[0068] Figure 3 This is a scanning electron microscope image of the lead iodide thin film prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0069] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0070] It should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0071] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0072] In a specific embodiment, the present invention provides a perovskite film preparation device, such as Figure 1 As shown, the perovskite film preparation equipment includes a vacuum film forming system 1 and an MFC gas flow control system 2, and the air inlet 5 of the vacuum film forming system 1 is connected to the MFC gas flow control system 2;

[0073] The vacuum film forming system 1 includes a vacuum unit 3 and a vacuum pumping unit 4 . The vacuum unit 3 includes a vacuum chamber 12 . The air outlet 6 of the vacuum chamber 12 is connected to the vacuum pumping unit 4 .

[0074] The vacuum chamber 12 is adjusted to a high vacuum state by the vacuum pumping unit 4 to remove various residual gas molecules in the coating environment to reduce adverse effects. This is because active molecules in the air may react with the film or the evaporated material to form compounds. Residual gas molecules enter the film and form impurities, affecting the film purity. Excessive gas molecules can hinder the straight-line movement of the atoms and molecules of the evaporated material, preventing many vapor molecules from reaching the substrate and thus preventing the formation of a continuous film on the substrate. However, high vacuum also reduces collisions between the evaporated material molecules and the residual gas molecules, increasing the mean free path, making the prepared film denser and less porous, hindering the penetration of the organic components in the second step, resulting in incomplete reaction and the possibility of metal halide residue.

[0075] Therefore, by adding an MFC gas flow control system 2 to the air inlet 5 of the vacuum film forming system 1, the present invention can ensure that the vacuum degree is controlled within a desired range. Within this range, the mean free path of the evaporating material molecules and the working gas molecules is shortened, and the kinetic energy of the material molecules and gas molecules reaching the substrate is reduced. This effectively controls the composition and quantity of the residual gas molecules in the device, keeping their effect on the evaporating material molecules within a controllable range. This allows the preparation of a loose and porous metal halide film without affecting the purity of the film, which facilitates the infiltration of the organic components in the second step and increases the nucleation and crystallization of the perovskite. Furthermore, the device can utilize different gases to modify the film within the vacuum chamber 12, controlling the film morphology, thereby producing high-quality, large-area perovskite films and excellent-performance battery devices. The device has a simple structure and highly stable process parameters, making it suitable for large-scale applications and mass production.

[0076] In the present invention, the selection of the vacuum unit 3 is not limited. For example, it can be a vacuum evaporation device, an ion sputtering device, a vacuum evaporation device for close-space sublimation, or a vacuum evaporation device used in a vapor transport method (VTD).

[0077] Furthermore, the MFC gas flow control system 2 includes an air intake source 7, a solenoid valve 8, an MFC controller 10 and a main air intake valve 11 connected in sequence along the air intake direction, and the air inlet 5 of the vacuum film forming system 1 is connected to the main air intake valve 11.

[0078] In the present invention, the air intake source 7 is not limited, and can be, for example, a cylinder or a pipeline.

[0079] In the present invention, the solenoid valve 8 can control the introduction of gas, the MFC controller 10 can adjust the flow rate of the introduced gas, and the main air inlet valve 11 is the switch for the gas to enter the vacuum unit 3.

[0080] Furthermore, a pressure reducing valve 9 is provided between the solenoid valve 8 and the MFC controller 10 .

[0081] In the present invention, the pressure reducing valve 9 can help the introduced gas to maintain a suitable and stable pressure range.

[0082] Furthermore, the vacuum unit 4 includes a molecular pump 15 and a mechanical pump 13 connected in sequence along the direction of gas outlet.

[0083] Furthermore, the gas outlet 6 of the vacuum chamber 12 includes a first gas outlet 18 and a second gas outlet 19 , and a gate valve 16 is provided between the molecular pump 15 and the first gas outlet 18 .

[0084] In the present invention, the gate valve 16 is used to open and close the molecular pump 15 and the first gas outlet 18 of the vacuum chamber 12 .

[0085] Furthermore, a front-stage valve 14 is provided between the molecular pump 15 and the mechanical pump 13 .

[0086] Furthermore, a pre-pumping valve 17 is provided between the mechanical pump 13 and the second air outlet 19 of the vacuum chamber 12 .

[0087] In another specific embodiment, the present invention provides a method for preparing a perovskite thin film, wherein the preparation method uses the above-mentioned perovskite thin film preparation equipment;

[0088] The preparation method comprises the following steps:

[0089] (1) placing the substrate in a vacuum chamber and evacuating the chamber using a vacuum pumping unit;

[0090] (2) introducing working gas through the MFC gas flow control system;

[0091] (3) vacuum depositing the raw materials on the surface of the substrate to form a metal halide film;

[0092] (4) An organic halide film is prepared on the surface of the metal halide film, and the perovskite film is obtained by heat treatment.

[0093] The technical solutions of the present invention are further illustrated below by specific examples. It should be understood by those skilled in the art that the examples are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0094] Example 1

[0095] This embodiment provides a method for preparing a perovskite thin film. The method adopts the perovskite thin film preparation arrangement provided in the above embodiment, and the method includes the following steps:

[0096] (1) using a magnetron sputtering method to prepare a nickel oxide thin film on FTO conductive glass to obtain a substrate;

[0097] (2) Place the substrate in a vacuum chamber, close the chamber door, open the pre-vacuum valve and mechanical pump, pump the chamber to a low vacuum state, then close the pre-vacuum valve, open the front stage valve, molecular pump, and gate valve in sequence, and pump the chamber vacuum to 1×10 - 5 Pa vacuum degree;

[0098] (3) Open the solenoid valve in the MFC gas flow control system, set the argon filling flow rate to 20 sccm in the MFC controller, open the main gas inlet valve and the pressure reducing valve, and the chamber vacuum is kept stable at 3×10 -4 Pa, turn on the evaporation source to deposit a lead iodide film, i.e., a metal halide film;

[0099] The evaporation source temperature is 300°C, the raw material for vacuum deposition is PbI2, the vacuum deposition rate is 10A / s, and the thickness of the metal halide film is 400nm.

[0100] (4) An organic halide solution was coated on the metal halide film using a slit coating method. The solutes of the organic halide solution included FAI, MAI, and MACl (at a molar ratio of 9:1:1). The solvent was isopropyl alcohol with a concentration of 0.5 mol / L. The coating speed was 30 mm / s, the dispensing volume per second was 40 μL / s, and the gap between the coating tip and the substrate was fixed at 100 μm.

[0101] After the organic halide solution is coated, the substrate is immediately transferred to an annealing box for direct annealing at a temperature of 300° C. for 15 minutes, so that the organic components react with the metal halide to form a perovskite film.

[0102] Example 2

[0103] The difference between this embodiment and embodiment 1 is that in step (3), the MFC controller sets the argon filling flow rate to 40 sccm. After the argon is introduced, the vacuum degree in the vacuum chamber is stably maintained at 5×10 -3 Pa.

[0104] The rest of the preparation methods and parameters remained the same as in Example 1.

[0105] Figure 2 The scanning electron microscope image of the lead iodide thin film prepared in this embodiment is shown. As can be seen from the image, the film layer is relatively loose and has many holes, which is conducive to the subsequent infiltration of organic components.

[0106] Example 3

[0107] The difference between this embodiment and embodiment 1 is that the working gas filled in step (3) is an argon-oxygen mixture, wherein the volume ratio of argon to oxygen is 93:7. After the argon-oxygen mixture is introduced, the vacuum degree in the vacuum chamber is stably maintained at 1×10 -4 Pa.

[0108] The rest of the preparation methods and parameters remained the same as in Example 1.

[0109] Example 4

[0110] This embodiment provides a method for preparing a perovskite film. The method adopts the perovskite film preparation arrangement provided in the above embodiment. The method comprises the following steps:

[0111] (1) using a magnetron sputtering method to prepare a nickel oxide thin film on FTO conductive glass to obtain a substrate;

[0112] (2) Place the substrate in a vacuum chamber, close the chamber door, open the pre-vacuum valve and mechanical pump, pump the chamber to a low vacuum state, then close the pre-vacuum valve, open the front stage valve, molecular pump, and gate valve in sequence, and pump the chamber vacuum to 5×10 - 5 Pa vacuum degree;

[0113] (3) Open the solenoid valve in the MFC gas flow control system, set the nitrogen filling flow rate to 10 sccm in the MFC controller, open the main air inlet valve and the pressure reducing valve, and the chamber vacuum is kept stable at 5×10 -4 Pa, turn on the evaporation source to deposit a lead iodide film, i.e., a metal halide film;

[0114] The evaporation source temperature is 200°C, the raw material for vacuum deposition is PbI2, the vacuum deposition rate is 1A / s, and the thickness of the metal halide film is 100nm.

[0115] (4) coating the metal halide film with an organic halide solution using a doctor blade method. The solutes of the organic halide solution include FAI, MAI, and MACl (molar ratio of 9:1:1), the solvent is isopropanol, the concentration is 1 mol / L, the coating speed is 30 mm / s, the dispensing volume per second is 40 μL / s, and the gap is 100 μm.

[0116] After the organic salt solution is coated, the substrate is immediately transferred to an annealing box for step-by-step annealing. The primary annealing temperature is 50°C for 5 minutes, and the secondary annealing temperature is 300°C for 15 minutes, so that the organic components react with the metal halide to form a perovskite film.

[0117] Example 5

[0118] This embodiment provides a method for preparing a perovskite film. The method adopts the perovskite film preparation arrangement provided in the above embodiment. The method comprises the following steps:

[0119] (1) using a magnetron sputtering method to prepare a nickel oxide thin film on FTO conductive glass to obtain a substrate;

[0120] (2) Place the substrate in a vacuum chamber, close the chamber door, open the pre-vacuum valve and mechanical pump, pump the chamber to a low vacuum state, then close the pre-vacuum valve, open the front stage valve, molecular pump, and gate valve in sequence, and pump the chamber vacuum to 1×10 - 4 Pa vacuum degree;

[0121] (3) Open the solenoid valve in the MFC gas flow control system, set the argon filling flow rate to 50 sccm in the MFC controller, open the main gas inlet valve and the pressure reducing valve, and the chamber vacuum is kept stable at 1×10 -3 Pa, turn on the evaporation source to deposit a lead iodide film, i.e., a metal halide film;

[0122] The evaporation source temperature is 400°C, the raw material for vacuum deposition is PbI2, the vacuum deposition rate is 20A / s, and the thickness of the metal halide film is 800nm.

[0123] (4) An organic salt solution was coated on the metal halide film using a slit coating method. The solutes of the organic halide solution included FAI, MAI, and MACl (molar ratio of 9:1:1), the solvent was isopropanol, the concentration was 1.5 mol / L, the coating speed was 30 mm / s, the dispensing volume per second was 40 μL / s, and the gap was 100 μm.

[0124] After the organic halide solution is coated, the substrate is immediately transferred to an annealing box for step-by-step annealing. The primary annealing temperature is 100°C for 1 minute, and the secondary annealing temperature is 500°C for 1 minute, so that the organic components react with the metal halide to form a perovskite film.

[0125] Example 6

[0126] The difference between this embodiment and embodiment 1 is that the working gas filled in step (3) is a mixture of argon gas and cesium chloride gas, wherein the volume ratio of argon gas to cesium chloride gas is 9:1.

[0127] The rest of the preparation methods and parameters remained the same as in Example 1.

[0128] Example 7

[0129] The difference between this embodiment and embodiment 1 is that in step (3), the argon filling flow rate is set to 100 sccm in the MFC controller.

[0130] The rest of the preparation methods and parameters remained the same as in Example 1.

[0131] Example 8

[0132] The difference between this embodiment and embodiment 1 is that after the argon gas is introduced in step (3), the vacuum degree of the chamber is stably maintained at 1×10 -5 Pa.

[0133] The rest of the preparation methods and parameters remained the same as in Example 1.

[0134] Example 9

[0135] The difference between this embodiment and embodiment 1 is that after the argon gas is introduced in step (3), the vacuum degree of the chamber is stably maintained at 1×10 -1 Pa.

[0136] The rest of the preparation methods and parameters remained the same as in Example 1.

[0137] Comparative Example 1

[0138] The difference between this comparative example and Example 1 is that the MFC gas flow control system in step (3) is omitted, that is, no working gas is charged.

[0139] The rest of the preparation methods and parameters remained the same as in Example 1.

[0140] Figure 3 The scanning electron microscope image of the lead iodide film prepared in this comparative example is shown. As can be seen from the image, the grains are flat and stacked without holes, which is not conducive to the subsequent infiltration of organic components.

[0141] Performance Testing

[0142] The perovskite thin films prepared on the substrates in Examples 1-9 and Comparative Example 1 were made into perovskite solar cells, specifically in the following steps:

[0143] On the surface of the above perovskite film, 20 nm thick C 60 and 5nm thick BCP, and finally thermal evaporation deposited 60nm thick Cu electrode to finally prepare a perovskite solar cell with an area of ​​1cm*1cm.

[0144] The photoelectric performance of the above-mentioned perovskite solar cell was tested.

[0145] Test conditions: AM1.5, 1000W / m 2 , 25±2℃;

[0146] The test results are shown in Table 1.

[0147] Table 1

[0148]

[0149]

[0150]

[0151] analyze:

[0152] As can be seen from the above table, the equipment and corresponding preparation method provided by the present invention can be used to prepare high-quality and large-area perovskite films and perovskite solar cells with excellent performance.

[0153] From the comparison of the data results of Example 1 and Example 2, it can be seen that the introduction of different flow rates of working gas has an impact on the quality of the lead iodide film. By controlling the flow rate of argon gas and then matching the appropriate organic concentration, the morphology of the perovskite film can be effectively improved, thereby improving the efficiency of the device.

[0154] From the comparison of the data results of Example 1 and Example 3, it can be seen that the introduction of different types of working gases has an impact on the quality of the lead iodide film. By controlling the filling flow rate at different levels and combining it with the reaction of the second step organic solvent, the morphology of the perovskite film can be effectively improved, thereby improving the efficiency of the device.

[0155] From the comparison of the data results of Example 1 and Example 7, it can be seen that if too much working gas is filled, the vacuum degree will be poor, resulting in uneven perovskite film formation, affecting the performance of the device and reducing the efficiency of the device.

[0156] From the comparison of the data results of Example 1 and Examples 8-9, it can be seen that if the chamber vacuum is too high after the introduction of argon gas, the gas has little effect on the metal halide film and the efficiency of the device cannot be improved; if the chamber vacuum is too low after the introduction of argon gas, the quality of the metal halide film is poor, and the perovskite film generated by the reaction with the organic solution in the second step is uneven and of low quality, resulting in a sharp drop in the efficiency of the device.

[0157] From the comparison of the data results of Example 1 and Comparative Example 1, it can be seen that the efficiency of the device can be effectively improved by appropriately introducing the working gas.

[0158] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a perovskite thin film, characterized in that: The preparation method uses perovskite thin film preparation equipment; The perovskite film preparation equipment includes a vacuum film forming system and an MFC gas flow control system; the air inlet of the vacuum film forming system is connected to the MFC gas flow control system; The vacuum film forming system includes a vacuum unit and a vacuum pumping unit, wherein the vacuum unit includes a vacuum chamber, and the air outlet of the vacuum chamber is connected to the vacuum pumping unit; The preparation method comprises the following steps: (1) Place the substrate in a vacuum chamber and evacuate the chamber using a vacuum pumping unit; (2) Introducing working gas through the MFC gas flow control system; (3) vacuum depositing the raw materials on the surface of the substrate to form a metal halide film; (4) preparing an organic halide film on the surface of the metal halide film, and obtaining the perovskite film through heat treatment; After the vacuuming unit is used for vacuuming in step (1), the vacuum degree in the vacuum chamber is less than or equal to 1×10 - 5 Pa; After the working gas is introduced in step (2), the vacuum degree in the vacuum chamber is stabilized at 1×10 -4 -2×10 -3 Within the range of Pa; The working gas in step (2) includes nitrogen and / or inert gas.

2. The preparation method according to claim 1, characterized in that The MFC gas flow control system includes an intake source, a solenoid valve, an MFC controller and a main intake valve that are connected in sequence along the intake direction.

3. The preparation method according to claim 2, characterized in that A pressure reducing valve is provided between the solenoid valve and the MFC controller.

4. The preparation method according to claim 1, characterized in that The vacuum pumping unit includes a molecular pump and a mechanical pump connected in sequence along the direction of gas outlet.

5. The preparation method according to claim 4, characterized in that The air outlet of the vacuum chamber includes a first air outlet and a second air outlet, and a gate valve is provided between the molecular pump and the first air outlet.

6. The preparation method according to claim 4, characterized in that A front-stage valve is provided between the molecular pump and the mechanical pump.

7. The preparation method according to claim 5, characterized in that A pre-pumping valve is provided between the mechanical pump and the second air outlet of the vacuum chamber.

8. The preparation method according to claim 1, characterized in that The working gas in step (2) further includes oxygen or cesium halide gas.

9. The preparation method according to claim 1, characterized in that The inert gas includes any one of argon, helium, neon or xenon, or a combination of at least two of them.

10. The preparation method according to claim 8, characterized in that The cesium halide gas includes any one of cesium iodide gas, cesium chloride gas or cesium bromide gas, or a combination of at least two of them.

11. The preparation method according to claim 1, characterized in that The gas flow rate of the working gas in step (2) is 0-50 sccm, excluding 0.

12. The preparation method according to claim 11, characterized in that The gas flow rate of the working gas in step (2) is 5-30 sccm.

13. The preparation method according to claim 1, characterized in that The raw materials in step (3) include lead halide.

14. The preparation method according to claim 13, characterized in that The lead halide includes any one of lead iodide, lead chloride or lead bromide, or a combination of at least two of them.

15. The preparation method according to claim 13, characterized in that The raw materials in step (3) also include cesium halide.

16. The preparation method according to claim 15, characterized in that The cesium halide includes any one of cesium iodide, cesium chloride or cesium bromide, or a combination of at least two of them.

17. The preparation method according to claim 1, characterized in that The deposition rate of the vacuum deposition in step (3) is 0.1-20Å / s.

18. The preparation method according to claim 17, characterized in that: The deposition rate of the vacuum deposition in step (3) is 1-5 Å / s.

19. The preparation method according to claim 1, characterized in that During the vacuum deposition process in step (3), the temperature of the evaporation source is 200-400°C.

20. The preparation method according to claim 1, characterized in that The thickness of the metal halide film in step (3) is 100-800 nm.

21. The preparation method according to claim 20, characterized in that The thickness of the metal halide film in step (3) is 300-500 nm.

22. The preparation method according to claim 1, characterized in that The method for preparing the organic halide film in step (4) includes a solution method or a vacuum method.

23. The preparation method according to claim 1, characterized in that The heat treatment method in step (4) includes direct annealing or step annealing.

24. The preparation method according to claim 23, characterized in that The direct annealing temperature is 100-500° C., and the time is 1-30 minutes.

25. The preparation method according to claim 23, characterized in that The stepwise annealing includes primary annealing and secondary annealing.

26. The preparation method according to claim 25, characterized in that The primary annealing is performed at a temperature of 25-100° C. and for a time of 1-30 minutes.

27. The preparation method according to claim 25, characterized in that The secondary annealing is performed at a temperature of 100-500° C. and for a time of 1-30 minutes.

28. A perovskite film, characterized in that The perovskite film is prepared by the preparation method according to any one of claims 1 to 27.

29. A perovskite battery, characterized in that: The perovskite cell comprises the perovskite thin film according to claim 28.

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