Perovskite battery, preparation method thereof and power utilization device

Abstract

The invention provides a perovskite cell and a preparation method thereof, and a power utilization device, the perovskite cell comprises a first electrode layer, a hole transport layer, a perovskite layer and a second electrode layer which are stacked in sequence, and the surface roughness of the hole transport layer is Ra1 and Ra1lt; and 3nm. According to the invention, the perovskite cell is improved, so that the device efficiency of the perovskite cell can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to perovskite cells and preparation methods and electrical devices thereof. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Perovskite solar cells are devices that use the photoelectric conversion mechanism of perovskite crystal materials to convert solar energy into electrical energy. They are the third generation of solar cells and have many advantages, such as high photoelectric conversion efficiency, simple manufacturing process, and low production cost. They have been extensively studied in recent years. Despite this, there is still a long way to go before perovskite cells can be commercialized and applied on a large scale. Among them, how to improve the device efficiency of perovskite cells is one of the key issues that need to be solved urgently. Summary of the invention

[0004] In view of the above problems, the present application provides a perovskite battery and a preparation method and an electrical device thereof. By improving the perovskite battery, the device efficiency of the perovskite battery can be improved.

[0005] In a first aspect, the present application provides a perovskite cell, which includes a first electrode layer, a hole transport layer, a perovskite layer, and a second electrode layer stacked in sequence, wherein the surface roughness of the hole transport layer is Ra1, Ra1<3nm.

[0006] In the above-mentioned perovskite cell provided in the present application, when the surface roughness Ra1 of the hole transport layer is less than 3nm, the flatness and smoothness of the film surface are relatively high, which can reduce the contact gap between the hole transport layer and the interface of the perovskite layer adjacent to it, improve the transmission efficiency of hole carriers, and thus improve the device efficiency of the perovskite cell.

[0007] In some embodiments, the surface roughness Ra1 of the hole transport layer satisfies: 0 <Ra1≤1.5nm。

[0008] The surface roughness of the hole transport layer is within the above range, which is beneficial to further reduce the contact gap between the hole transport layer and the perovskite layer, further improve the transmission efficiency of hole carriers, and thus further improve the device efficiency of the perovskite battery.

[0009] In some embodiments, the number of pinholes per unit area of ​​the hole transport layer is n1, 0≤n1≤2, and can be optionally 0≤n1≤1.

[0010] The number of pinholes per unit area of ​​the hole transport layer is within the above range, which is beneficial to reducing the contact gap between the hole transport layer and the interface of the perovskite layer adjacent to it (such as the lower interface of the perovskite layer), thereby facilitating the through-growth of grains in the perovskite layer and the transport of hole carriers, thereby improving the device efficiency of the perovskite battery.

[0011] In some embodiments, the perovskite layer comprises crystal grains distributed throughout the thickness direction of the perovskite layer;

[0012] Optionally, the average size of the grains is 600nm to 800nm, and optionally 650nm to 750nm.

[0013] The perovskite layer of the present application contains grains distributed throughout the thickness direction of the perovskite layer, which is beneficial to reduce the mutual stacking of grains, thereby reducing the number of grain boundaries generated by the mutual stacking of grains, reducing the occurrence of non-radiative recombination at grain boundaries, improving the carrier transmission efficiency, inhibiting ion migration, and reducing deep energy level defects, thereby improving the device efficiency and stability of the perovskite battery.

[0014] In some embodiments, the surface roughness of the perovskite layer is Ra2, Ra2<3nm, and can be 0 <Ra2≤1.5nm。

[0015] When the surface roughness of the perovskite layer Ra2<3nm, the flatness and smoothness of the film surface are relatively high, which can reduce the contact gap between the interfaces of the adjacent charge transport layers (hole transport layers or electron transport layers) and improve the carrier transport efficiency, thereby improving the device efficiency of the perovskite battery.

[0016] In some embodiments, the number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤2, and optionally 0≤n2≤1.

[0017] The number of pinholes per unit area of ​​the perovskite layer is within the above range, which is beneficial to improving the density of the perovskite layer, reducing leakage current, and at the same time reducing the contact gap between the hole transport layer and the charge transport layer (hole transport layer or electron transport layer) arranged adjacent to it, thereby improving the carrier transport efficiency and further improving the device efficiency of the perovskite battery.

[0018] In some embodiments, the perovskite cell satisfies at least one of the following conditions:

[0019] (1) The thickness of the hole transport layer is 10 nm to 30 nm, and can be 15 nm to 25 nm;

[0020] (2) The thickness of the perovskite layer is 700 nm to 1200 nm, and can be optionally 800 nm to 1000 nm.

[0021] The thickness of the perovskite layer is within the above range, which is beneficial to promoting the transmission and collection of carriers, thereby promoting the improvement of the efficiency of perovskite battery devices.

[0022] In some embodiments, the perovskite cell satisfies at least one of the following conditions:

[0023] (1) The perovskite layer comprises a compound ABX3 or A2CDX6, wherein the A ion is a monovalent cation, the B ion is a divalent cation, the C ion is a monovalent cation, the D ion is a trivalent cation, and the X ion is a monovalent anion;

[0024] Optionally, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of;

[0025] Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole;

[0026] Optionally, the A ions include organic amine ions and Cs + One or more of;

[0027] Optionally, the B ions include Pb 2+ Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ , Fe 2+ 、Co 2+ , Cu 2+ and Ni 2+ One or more of;

[0028] Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following:

[0029] Optionally, the C ions include Cs + 、Ag + , K + And Ru + One or more of;

[0030] Optionally, the D ions include Bi 3+ 、Ni 3+ , Fe 3+and Cu 3+ One or more of;

[0031] Optionally, the X ions include F - , Cl - Br - and I - One or more of;

[0032] Optionally, the X ions include Cl - Br - and I - One or more of;

[0033] Optionally, the perovskite layer comprises compound APb y Sn 1-y X3,0 <y<1;

[0034] (2) The perovskite cell further includes an electron transport layer, which is disposed between the perovskite layer and the second electrode layer.

[0035] In a second aspect, the present application provides a method for preparing a perovskite battery, which comprises:

[0036] A hole transport layer is prepared on the first electrode layer, wherein the surface roughness of the hole transport layer is Ra1, Ra1<3nm;

[0037] A perovskite layer and a second electrode layer are sequentially stacked on the hole transport layer to obtain a perovskite cell.

[0038] In the perovskite cell prepared by the above method, the surface roughness of the hole transport layer Ra1<3nm, so that the flatness and smoothness of the film surface of the hole transport layer are relatively high, which can reduce the contact gap between the hole transport layer and the perovskite layer interface disposed adjacent thereto, improve the transmission efficiency of hole carriers, and thus improve the device efficiency of the perovskite cell.

[0039] In some embodiments, the step of preparing a hole transport layer on the first electrode layer comprises:

[0040] preparing the hole transport layer on the first electrode layer by a first vacuum flash evaporation method;

[0041] Optionally, preparing the hole transport layer by the first vacuum flash evaporation method comprises:

[0042] Applying a solution of a hole transport material on the first electrode layer to form a wet film of the hole transport material;

[0043] Performing the first vacuum flash evaporation treatment on the wet film of the hole transport material to flash evaporate the solvent in the hole transport material solution to form the hole transport layer;

[0044] Optionally, the first vacuum flash treatment is performed in an air atmosphere.

[0045] In the above-mentioned method for preparing perovskite cells provided in the present application, the hole transport layer is prepared by vacuum flash evaporation. Since vacuum flash evaporation can quickly extract and remove the solvent in the solution of the hole transport material, the process time can be greatly shortened.

[0046] In some embodiments, the method satisfies at least one of the following conditions:

[0047] (1) The temperature of the first vacuum flash treatment is 15°C to 35°C;

[0048] (2) The extraction rate of the first vacuum flash treatment is 5m 3 / h~20m 3 / h;

[0049] (3) The hole transport material includes one or more of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, polytriarylamine, poly-3,4-ethylenedioxythiophene: polystyrene sulfonate, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, and N-(4-phenylamino)carbazole-spirobifluorene.

[0050] Optionally, it may be poly (3,4-ethylenedioxythiophene):polystyrene sulfonate.

[0051] The temperature of the first vacuum flash evaporation treatment is within the above range, which is beneficial to reduce the generation of small cracks or wrinkles inside and on the surface of the hole transport layer film, reduce the roughness of the film surface, and improve the flatness of the film surface, thereby improving the device efficiency of the perovskite battery.

[0052] In some embodiments, the perovskite layer is prepared by a second vacuum flash evaporation method.

[0053] In some embodiments, the perovskite layer is prepared by the second vacuum flash evaporation method, comprising:

[0054] coating a perovskite precursor solution on the hole transport layer to form a perovskite wet film;

[0055] Performing a second vacuum flash evaporation treatment on the perovskite wet film to flash evaporate the solvent in the perovskite precursor solution to form a perovskite mesophase film;

[0056] Annealing the perovskite intermediate phase film to form the perovskite layer;

[0057] Optionally, the second vacuum flash treatment is performed in a nitrogen atmosphere.

[0058] By preparing the perovskite layer by vacuum flash evaporation, it is possible to effectively control the grain growth and surface morphology inside the perovskite layer, improve the film quality of the perovskite layer, and thereby improve the device efficiency of the perovskite battery.

[0059] In some embodiments, the method satisfies at least one of the following conditions:

[0060] (1) The temperature of the second vacuum flash treatment is 15°C to 35°C, and can be optionally 18°C ​​to 22°C;

[0061] (2) The extraction rate of the second vacuum flash treatment is 10m 3 / h~30m 3 / h; optional: 15m 3 / h~30m 3 / h;

[0062] (3) The annealing temperature is 70°C to 130°C, and can be 100°C to 130°C;

[0063] (4) The annealing time of the annealing treatment is 5 min to 30 min, and can be optionally 10 min to 20 min;

[0064] (5) The perovskite precursor solution contains a compound ABX3 or A2CDX6, wherein the A ion is a monovalent cation, the B ion is a divalent cation, the C ion is a monovalent cation, the D ion is a trivalent cation, and the X ion is a monovalent anion;

[0065] Optionally, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of;

[0066] Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole;

[0067] Optionally, the A ions include organic amine ions and Cs + One or more of;

[0068] Optionally, the B ions include Pb 2+ Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ , Fe 2+ 、Co 2+ , Cu 2+ and Ni 2+ One or more of;

[0069] Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following:

[0070] Optionally, the C ions include Cs + 、Ag + , K + And Ru + One or more of;

[0071] Optionally, the D ions include Bi 3+ 、Ni 3+ , Fe 3+ and Cu 3+ One or more of;

[0072] Optionally, the X ions include F - , Cl - Br - and I - One or more of;

[0073] Optionally, the X ions include Cl - Br - and I - One or more of;

[0074] Optionally, the perovskite precursor solution comprises compound APb y Sn 1-y X3,0 <y<1。

[0075] By preparing the perovskite layer by vacuum flash evaporation, the solvent in the perovskite precursor solution can be quickly extracted, the nucleation and crystallization rate of the perovskite can be slowed down, the average size of the grains in the perovskite layer can be increased, and at the same time, it is beneficial to promote the growth of grains through the thickness direction of the perovskite layer, improve the consistency and uniformity of grain growth, and reduce the mutual stacking of grains. This can reduce the number of grain boundaries between grains, reduce the occurrence of non-radiative recombination at grain boundaries, improve the carrier transmission efficiency, inhibit ion migration, and reduce deep energy level defects, thereby improving the device efficiency and stability of perovskite batteries.

[0076] In some embodiments, the method further comprises: preparing an electron transport layer between the perovskite layer and the second electrode layer.

[0077] In a third aspect, the present application provides a photovoltaic module, comprising the perovskite cell described in the first aspect of the present application or the perovskite cell prepared by the method described in the second aspect of the present application.

[0078] In a fourth aspect, the present application provides an electrical device comprising at least one of the perovskite cell described in the first aspect of the present application, the perovskite cell produced by the method described in the second aspect of the present application, and the photovoltaic module described in the third aspect of the present application.

[0079] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to better describe and illustrate the embodiments or examples of those applications disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of any of the disclosed applications, the embodiments or examples currently described, and the best modes of these applications currently understood. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the accompanying drawings:

[0081] Figure 1 Schematic diagram of a perovskite cell according to one embodiment of the present application.

[0082] Figure 2 Schematic diagram of a perovskite cell according to one embodiment of the present application.

[0083] Figure 3 Schematic diagram of a perovskite cell according to one embodiment of the present application.

[0084] Figure 4 It is a schematic diagram of an apparatus for performing vacuum flash evaporation according to one embodiment of the present application.

[0085] Figure 5Surface morphology of the hole transport layer in the perovskite battery of Example 1 (Figure (b)) and Comparative Example 1 (Figure (a)).

[0086] Figure 6 These are cross-sectional morphology images of the hole transport layer in the perovskite battery of Example 1 at different magnifications.

[0087] Figure 7 Surface morphology of the perovskite layer in the perovskite cells of Example 1 (Figure (b)) and Example 18 (Figure (a)).

[0088] Figure 8 These are cross-sectional morphology images of the perovskite layer in the perovskite cell of Example 18 at different magnifications.

[0089] Fig. 9 These are cross-sectional morphology images of the perovskite layer in the perovskite cell of Example 1 at different magnifications.

[0090] Fig.10 A schematic diagram of an electrical device using a perovskite battery according to an embodiment of the present application as a power source.

[0091] Description of reference numerals:

[0092] 10 substrate layer; 20 first electrode layer; 30 hole transport layer; 40 perovskite layer; 50 electron transport layer; 60 second electrode layer. DETAILED DESCRIPTION

[0093] Below, some embodiments of the perovskite battery and its preparation method and the electrical device of the present application are described in detail with appropriate reference to the drawings. However, there are cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0094] "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 ​​or not 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 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all 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. 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 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0095] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0096] 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.

[0097] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0098] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0099] In this application, in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and should be understood not to constitute a closed limitation on quantity.

[0100] In a perovskite solar cell, especially in a narrow-bandgap tin-lead perovskite solar cell, for a hole transport layer formed by a conventional method (coating + annealing), there are usually many small cracks or wrinkles on its film surface, making the film surface uneven and increasing the contact gaps between the hole transport layer and the perovskite layer, which affects the transport of hole carriers and further affects the device efficiency of the perovskite solar cell.

[0101] Based on this, in the first aspect, this application provides a perovskite solar cell, as Figure 1 shown, which includes a first electrode layer 20, a hole transport layer 30, a perovskite layer 40, and a second electrode layer 60 stacked in sequence, wherein the surface roughness of the hole transport layer 30 is Ra1, and Ra1 < 3 nm.

[0102] In the above perovskite solar cell provided by this application, when the surface roughness Ra1 of the hole transport layer < 3 nm, the flatness and smoothness of its film surface are relatively high, so that the contact gaps between the hole transport layer and the perovskite layer adjacent thereto can be reduced, the transport efficiency of hole carriers can be improved, and thus the device efficiency of the perovskite solar cell can be improved.

[0103] In some embodiments, the surface roughness Ra1 of the hole transport layer satisfies: 0 < Ra1 ≤ 1.5 nm. For example, Ra1 can be 0.01 nm, 0.05 nm, 0.1 nm, 0.3 nm, 0.5 nm, 0.7 nm, 0.9 nm, 1.1 nm, 1.3 nm, 1.5 nm or within the range composed of any of the above values.

[0104] It can be understood that the surface roughness of the hole transport layer is Ra1, which can be the surface roughness of the side of the hole transport layer that is relatively far from the first electrode layer and relatively close to the perovskite layer.

[0105] When the surface roughness of the hole transport layer is within the above range, it is beneficial to further reduce the contact gaps between the hole transport layer and the perovskite layer, further improve the transport efficiency of hole carriers, and thus further improve the device efficiency of the perovskite solar cell.

[0106] In some embodiments, the number of pinholes per unit area of ​​the hole transport layer is n1, 0≤n1≤2. Optionally, the number of pinholes per unit area of ​​the hole transport layer is 0≤n1≤1.

[0107] The number of pinholes per unit area of ​​the hole transport layer is within the above range, which is beneficial to reducing the contact gap between the hole transport layer and the interface of the perovskite layer adjacent to it (such as the lower interface of the perovskite layer), thereby facilitating the through-growth of grains in the perovskite layer and the transport of hole carriers, thereby improving the device efficiency of the perovskite battery.

[0108] In some embodiments, the thickness of the hole transport layer is 10 nm to 30 nm. For example, the thickness of the hole transport layer can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, or within a range of any of the above values. Optionally, the thickness of the hole transport layer is 15 nm to 25 nm.

[0109] The thickness of the hole transport layer is within the above range, which is beneficial to promoting the transport and collection of hole carriers, thereby promoting the improvement of the efficiency of perovskite battery devices.

[0110] In some embodiments, the perovskite layer comprises grains distributed throughout the thickness direction of the perovskite layer (see Fig. 9 ).

[0111] It can be understood that the perovskite layer contains grains distributed throughout the thickness direction of the perovskite layer, which means that among the grains contained in the perovskite layer, there are grains that grow and distribute throughout the perovskite layer along the stacking direction of each layer of the perovskite battery, that is, the axial direction of the grain is approximately perpendicular to the film surface of the perovskite layer, and the two ends of the grain are respectively close to the upper and lower interfaces of the perovskite layer.

[0112] In conventional perovskite layers, the grain size is usually small, so the grains are stacked on top of each other (see Figure 8 ), such mutual stacking of grains will produce a large number of grain boundaries, and non-radiative recombination is prone to occur at these interfaces, which in turn affects carrier transport, promotes ion migration, introduces deep energy level defects, and causes a decrease in the device efficiency and stability of the perovskite battery. The perovskite layer of the present application contains grains distributed throughout the thickness direction of the perovskite layer, which is conducive to reducing the mutual stacking of grains, thereby reducing the number of grain boundaries generated by the mutual stacking of grains, reducing the occurrence of non-radiative recombination at grain boundaries, improving the carrier transport efficiency, inhibiting ion migration, and reducing deep energy level defects, thereby improving the device efficiency and stability of the perovskite battery.

[0113] In some embodiments, the average size of the crystal grains is 600nm to 800nm. For example, the average size of the crystal grains can be 600nm, 620nm, 640nm, 660nm, 680nm, 700nm, 720nm, 740nm, 760nm, 780nm, 800nm ​​or within a range of any of the above values. Optionally, the average size of the crystal grains is 650nm to 750nm.

[0114] The average size of the crystal grains is well known in the art and can be measured by methods known in the art, for example, by using a scanning electron microscope; during the measurement, the crystal grains can be observed and measured on a unit area of ​​the perovskite layer.

[0115] The average grain size is within the above range, which is beneficial to reducing the number of grains and grain boundaries per unit area of ​​the perovskite layer, thereby reducing the occurrence of non-radiative recombination at the grain boundaries, improving the carrier transmission efficiency, inhibiting ion migration, and reducing deep energy level defects, thereby further improving the device efficiency and stability of the perovskite battery.

[0116] In some embodiments, the surface roughness of the perovskite layer is Ra2, Ra2<3nm, for example, Ra2 may be 0.01nm, 0.05nm, 0.1nm, 0.3nm, 0.5nm, 0.7nm, 0.9nm, 1.1nm, 1.3nm, 1.5nm, 1.7nm, 1.9nm, 2.1nm, 2.3nm, 2.5nm, 2.7nm, 2.9nm, 3nm or within a range of any of the above values. Optionally, 0 <Ra2≤1.5nm。

[0117] It can be understood that the surface roughness of the perovskite layer is Ra2, which means that the surface roughness of the perovskite layer on the side relatively far from the hole transport layer and relatively close to the second electrode layer is Ra2.

[0118] When the surface roughness of the perovskite layer Ra2<3nm, the flatness and smoothness of the film surface are relatively high, which can reduce the contact gap between the interfaces of the adjacent charge transport layers (hole transport layers or electron transport layers) and improve the carrier transport efficiency, thereby improving the device efficiency of the perovskite battery.

[0119] In some embodiments, the number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤2. Optionally, 0≤n2≤1.

[0120] The number of pinholes per unit area of ​​the perovskite layer is within the above range, which is beneficial to improving the density of the perovskite layer, reducing leakage current, and at the same time reducing the contact gap between the hole transport layer and the charge transport layer (hole transport layer or electron transport layer) arranged adjacent to it, thereby improving the carrier transport efficiency and further improving the device efficiency of the perovskite battery.

[0121] In some embodiments, the thickness of the perovskite layer is 700 nm to 1200 nm. For example, the thickness of the perovskite layer can be 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, or within a range of any of the above values. Optionally, the thickness of the perovskite layer is 800 nm to 1000 nm.

[0122] The thickness of the perovskite layer is within the above range, which is beneficial to promoting the transmission and collection of carriers, thereby promoting the improvement of the efficiency of perovskite battery devices.

[0123] In the present application, the surface roughness of the hole transport layer and the perovskite layer is known in the art and can be tested by methods known in the art. For example, the surface roughness of the hole transport layer and the perovskite layer can be characterized and tested by atomic force microscopy (AFM).

[0124] In the present application, the number of pinholes per unit area of ​​the hole transport layer and the perovskite layer has a well-known meaning in the art and can be measured by methods known in the art. For example, the number of pinholes per unit area of ​​the hole transport layer and the perovskite layer can be characterized by an atomic force microscope (AFM).

[0125] In the present application, the thickness of the hole transport layer and the perovskite layer has a well-known meaning in the art and can be measured by methods known in the art, for example, by using a micrometer.

[0126] In some embodiments, the perovskite layer comprises ABX3 or A2CDX6, wherein the A ion is a monovalent cation, the B ion is a divalent cation, the C ion is a monovalent cation, the D ion is a trivalent cation, and the X ion is a monovalent anion.

[0127] In some embodiments, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of .

[0128] In some embodiments, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl, and imidazole.

[0129] In some embodiments, the A ions include organic amine ions and Cs + One or more of .

[0130] In some embodiments, the B ions include Pb 2+ Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ , Fe 2+ 、Co 2+ , Cu 2+ and Ni 2+ One or more of .

[0131] Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following.

[0132] In some embodiments, the C ions include Cs + 、Ag + , K + And Ru + One or more of.

[0133] In some embodiments, the D ions include Bi 3+ 、Ni 3+ , Fe 3+ and Cu 3+ One or more of .

[0134] In some embodiments, the X ions include F - , Cl - Br - and I - One or more of .

[0135] Optionally, the X ions include Cl - Br - and I - One or more of .

[0136] Optionally, the perovskite layer comprises compound APb y Sn 1-y X3,0 <y<1。

[0137] In some embodiments, the perovskite cell of the present application may be a tin-lead perovskite cell. The perovskite layer comprises the above-mentioned compound APb y Sn 1-y X3,0 <y<1。

[0138] In some embodiments, Figure 2 As shown, the perovskite cell further includes an electron transport layer 50 , and the electron transport layer 50 is disposed between the perovskite layer 40 and the second electrode layer 60 .

[0139] In some embodiments, Figure 2 As shown, the perovskite cell comprises a first electrode layer 20, a hole transport layer 30, a perovskite layer 40, an electron transport layer 50 and a second electrode layer 60 which are stacked in sequence. Further, it can be any one of an inverted pin cell and a formal nip cell.

[0140] In some embodiments, one of the "first electrode" and the "second electrode" is a transparent electrode for light incidence. In some embodiments, the first electrode layer is a transparent electrode layer.

[0141] In some embodiments, the material of the transparent electrode may be exemplified by, but not limited to, one or more of the following materials: FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), IZO (indium zinc oxide), IWO (tungsten-doped indium oxide), etc.

[0142] In some embodiments, the second electrode comprises a conductive material, and further, the conductive material may be an organic conductive material, an inorganic conductive material, or a combination thereof. Non-limiting examples of inorganic conductive materials include metal conductive materials, and further, the metal conductive material may include any one of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), etc., or any suitable mixture of the aforementioned elements. The conductive material may include a conductive oxide, and further, the conductive material may be a conductive oxide; non-limiting examples of conductive oxides may include one or more of FTO, ITO, IWO, AZO, etc.

[0143] In some embodiments, the perovskite cell is any one of an inverted pin cell and a formal nip cell.

[0144] The perovskite cells provided in this application may include formal and trans forms.

[0145] Officially, the perovskite cell includes a transparent electrode and an electron transport layer, a perovskite layer, a hole transport layer and a second electrode layer stacked in sequence on the transparent electrode.

[0146] For the trans type, the perovskite cell comprises a transparent electrode and a hole transport layer, a perovskite layer, an electron transport layer and a second electrode layer sequentially stacked on the transparent electrode, wherein the transparent electrode is used for light incidence.

[0147] The perovskite layer described in the present application is a light-absorbing layer in a perovskite cell.

[0148] When the perovskite battery is working, after the light-absorbing layer is exposed to light, the internal electrons gain energy and break free from the light-absorbing layer to form negatively charged electron carriers, and at the same time form positively charged hole carriers, thereby obtaining electron-hole pairs. Free electrons and free holes are transmitted in opposite directions through the corresponding transport layer, so that electrons and holes flow, forming external current, and realizing the conversion of light energy into electrical energy. Further, after the perovskite layer absorbs photons, it is stimulated to generate electron-hole pairs, which further dissociate to form free carriers with opposite charges. The free electrons are transmitted to the positive electrode through the electron transport layer, and the free holes are transmitted to the negative electrode through the hole transport layer. The two free carriers are collected by the corresponding electrodes, further forming photocurrent in the circuit of the perovskite battery.

[0149] The electron transport layer can extract and transport electron carriers and block the passage of free holes.

[0150] The hole transport layer can extract and transport hole carriers and block the passage of free electrons.

[0151] It can be understood that the perovskite battery includes two electrodes, a first electrode and a second electrode, one of which serves as a positive electrode and can collect electron carriers transmitted via an electron transport layer, and the other serves as a negative electrode and can collect hole carriers transmitted via a hole transport layer.

[0152] In some embodiments, the electron transport layer material may include but is not limited to one or more of the following materials and their derivatives: imide compounds, quinone compounds, fullerenes and their derivatives, methoxytriphenylamine-fluoroformamidine (OMeTPA-FA), calcium titanate (CaTiO3), lithium fluoride (LiF), calcium fluoride (CaF2), poly (3,4-ethylenedioxythiophene): polystyrene sulfonic acid (PEDOT:PSS), poly 3-hexylthiophene (P3HT), triphenylamine (H101) with triptycene as the core, 3,4 -ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-phenylamino)carbazole-spirobifluorene (CzPAF-SBF), polythiophene, metal oxides, silicon oxide (SiO2), strontium titanate (SrTiO3), cuprous thiocyanate (CuSCN), etc.; wherein the metal elements may include one or more of Mg, Ni, Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga and Cr.

[0153] In some embodiments, the hole transport layer may include, but is not limited to, one or more of the following materials and their derivatives: 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), polytriarylamine (PTAA), nickel oxide (NiO x ), poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS), WO3 and other materials can transport holes and block electrons.

[0154] Optionally, the hole transport layer comprises poly (3,4-ethylenedioxythiophene):polystyrene sulfonate.

[0155] In some embodiments, the perovskite cell may further include a substrate layer.

[0156] In some embodiments, Figure 3 As shown, the perovskite cell includes the following structures arranged in sequence: a substrate layer 10 (which may be a glass substrate or a flexible substrate), a first electrode layer 20, a hole transport layer 30, a perovskite layer 40, an electron transport layer 50, and a second electrode layer 60. Among them, the flexible substrate may include one or more materials selected from polyethylene terephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyethylene naphthalate, etc. Optionally, the first electrode layer is a transparent electrode layer for light incidence.

[0157] In some embodiments, the perovskite cell comprises the following structures arranged in sequence: a substrate layer (glass substrate or flexible substrate), a first electrode layer, an electron transport layer, a perovskite layer, a hole transport layer, and a second electrode layer. Optionally, the first electrode is a transparent electrode for light incidence. The definition of the flexible substrate can be found in the above text.

[0158] The substrate layer involved in the implementation manner or example of the present application may be, but is not limited to, a glass substrate or a flexible substrate.

[0159] In some embodiments, the substrate layer is a flexible substrate layer. Further, the material of the substrate layer may be, for example (but not limited to), an organic polymer material, and further, may be mixed in different proportions with one or more of the following materials: including but not limited to polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), etc.

[0160] In the present application, the specifications of the perovskite cell are not particularly limited and may be, but not limited to, 300 mm×300 mm.

[0161] It can be understood that the structure of the perovskite battery involved in the present application may not be limited to the structural layers listed above. Other functional layers, such as buffer layers, can also be introduced as needed. In some embodiments, the perovskite battery can be provided with a buffer layer with a suitable energy level, which can play a role in reducing energy level barriers, promoting energy level matching, improving carrier extraction efficiency, and at the same time, passivating interface defect states, protecting light absorption layers, inhibiting water molecules, oxygen oxidation and decomposition of batteries, improving photoelectric conversion efficiency, and improving the stability of perovskite batteries. One or more of the above. Depending on the location of the buffer layer, the type of buffer layer may include a buffer layer between the hole transport layer and the anode, a buffer layer between the electron transport layer and the cathode, a buffer layer between the hole transport layer and the absorption layer, and a buffer layer between the electron transport layer and the absorption layer. The materials that can be used for the buffer layer in the perovskite battery may include, but are not limited to: Cu2O, NiO, AZO, TiO2, etc.

[0162] In a second aspect, the present application provides a method for preparing a perovskite battery, which is used to prepare the perovskite battery described in the first aspect of the present application, and may include the following steps:

[0163] S10, preparing a hole transport layer on the first electrode layer, wherein the surface roughness of the hole transport layer is Ra1, Ra1<3 nm;

[0164] S20, preparing a perovskite layer and a second electrode layer in sequence on the hole transport layer to obtain a perovskite cell.

[0165] In the perovskite cell prepared by the above method, the surface roughness of the hole transport layer Ra1<3nm, so that the flatness and smoothness of the film surface of the hole transport layer are relatively high, which can reduce the contact gap between the hole transport layer and the perovskite layer interface disposed adjacent thereto, improve the transmission efficiency of hole carriers, and thus improve the device efficiency of the perovskite cell.

[0166] In some embodiments, the step S10 may further include: preparing the hole transport layer on the first electrode layer by a first vacuum flash evaporation method.

[0167] It can be understood that the principle of vacuum flash evaporation described in the present application includes a process in which a liquid is superheated in a vacuum environment and rapidly evaporates into steam. During the vacuum flash evaporation process, the pressure of the environment in which the droplet is located drops rapidly, causing the entire droplet to be in an overheated state, and at this time, flash evaporation occurs not only on the surface of the droplet, but also inside the droplet.

[0168] When preparing perovskite cells, the traditional method is usually to prepare the hole transport layer by coating + annealing, that is, firstly, the solution of the hole transport material needs to be coated on the electrode (such as a transparent conductive glass substrate), and then annealed within a certain temperature range to form a hole transport layer film on the electrode. This process not only takes a long time, but more importantly, when the hole transport layer film is annealed, it will produce strain due to heat, causing small cracks or wrinkles inside and on the surface of the film, resulting in an uneven surface of the film, and more pinholes inside the film, which increases the contact gap between the interface and the adjacent perovskite layer, reducing the device efficiency of the perovskite cell.

[0169] In the above-mentioned method for preparing perovskite cells provided in the present application, the hole transport layer is prepared by vacuum flash evaporation. Since vacuum flash evaporation can quickly extract and remove the solvent in the solution of the hole transport material, the process time can be greatly shortened. More importantly, the use of vacuum flash evaporation to prepare the hole transport layer can omit the annealing process (temperature is usually 100°C to 160°C) in the traditional method, which can reduce the generation of small cracks or wrinkles inside and on the surface of the hole transport layer film caused by this, reduce the number of pinholes inside the film, reduce the roughness of the film surface, and improve the flatness of the film surface, thereby reducing the contact gap between the hole transport layer and the perovskite layer interface, and is conducive to the through-growth of grains in the perovskite layer and the collection of hole carriers, which is conducive to improving the device efficiency of the perovskite cell.

[0170] In some embodiments, preparing the hole transport layer by the first vacuum flash evaporation method may include the following steps:

[0171] S110, coating a solution of a hole transport material on the first electrode layer to form a wet film of the hole transport material;

[0172] S120 , performing the first vacuum flash evaporation treatment on the wet film of the hole transport material to flash evaporate the solvent in the hole transport material solution to form the hole transport layer.

[0173] In the above steps, by performing a first vacuum flash evaporation treatment on the wet film of the hole transport material, the solvent in the hole transport material solution can be flash evaporated, that is, the solvent evaporates in a very short time, and the hole transport material is formed into a film in a very short time. The hole transport layer thus formed has a relatively high surface flatness and smoothness, and there are very few cracks inside and on the surface of the film, which is beneficial to improving the device efficiency of the perovskite battery.

[0174] In some embodiments, the hole transport material includes one or more of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), polytriarylamine (PTAA), poly-3,4-ethylenedioxythiophene:polystyrene sulfonate, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, and N-(4-phenylamino)carbazole-spirobifluorene. Poly-3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS) may be selected.

[0175] In some embodiments, the first vacuum flash treatment may be performed in an air atmosphere.

[0176] It can be understood that since the hole transport material solution is usually an aqueous solution of a polymer, especially in tin-lead perovskite batteries, the hole transport material solution usually adopts a poly (3,4-ethylenedioxythiophene: polystyrene sulfonate) (PEDOT: PSS) aqueous solution; therefore, when the first vacuum flash treatment is performed, impurities such as water and oxygen in the air will basically not affect the hole transport material, and the first vacuum flash treatment can be directly performed in an air atmosphere.

[0177] In some embodiments, the temperature of the first vacuum flash treatment is 15° C. to 35° C. For example, the temperature of the first vacuum flash treatment can be 15° C., 20° C., 25° C., 30° C., 35° C. or any range thereof.

[0178] It can be understood that when the first vacuum flash evaporation treatment is performed, the temperatures of the first electrode layer and the hole transport material solution are both within the above range.

[0179] The temperature of the first vacuum flash evaporation treatment is within the above range, which is beneficial to reduce the generation of small cracks or wrinkles inside and on the surface of the hole transport layer film, reduce the roughness of the film surface, and improve the flatness of the film surface, thereby improving the device efficiency of the perovskite battery.

[0180] In some embodiments, the extraction rate of the first vacuum flash treatment is 5m 3 / h~20m 3 For example, the extraction rate of the first vacuum flash treatment can be 5m 3 / h,7m 3 / h,10m 3 / h,13m 3 / h,15m 3 / h,17m 3 / h,20m 3 / h or within the range of any of the above values. Optionally, the extraction rate of the first vacuum flash treatment is 15m 3 / h~20m 3 / h.

[0181] The extraction rate of the first vacuum flash evaporation treatment is within the above range, which is beneficial to improving the film formation quality of the hole transport layer, thereby improving the device efficiency of the perovskite battery.

[0182] It can be understood that the extraction rate and extraction time of the first vacuum flash treatment are related to the power of the first vacuum flash treatment and the equipment used to implement the first vacuum flash treatment. The power can be adjusted according to the internal capacity of the equipment and the actual preparation requirements, and thus the extraction rate and extraction time can also be adjusted accordingly.

[0183] In some embodiments, the extraction time of the first vacuum flash treatment is 10s to 180s. For example, the extraction time can be 10s, 50s, 90s, 130s, 170s, 180s or within a range of any of the above values. Optionally, the extraction time is 30s to 60s.

[0184] As a non-limiting example, Figure 4 As shown, the wet film of the hole transport material can be placed in a sealed container through an opening at one end of the sealed container, and a vacuum pump is connected to the other end of the container through the opening, and the first vacuum flash evaporation treatment can be performed through the container and the vacuum pump. That is, the air in the container and the solvent in the wet film of the hole transport material can be quickly extracted by the vacuum pump, thereby forming a thin film of the hole transport layer.

[0185] It can be understood that, in the perovskite battery of the present application, on the basis of the hole transport layer being prepared by vacuum flash evaporation, the perovskite layer can also be prepared by vacuum flash evaporation. That is, when preparing the perovskite battery of the present application, only the hole transport layer can be prepared by vacuum flash evaporation; or both the hole transport layer and the perovskite layer can be prepared by vacuum flash evaporation.

[0186] Optionally, on the basis of the hole transport layer being prepared by a first vacuum flash evaporation method, the perovskite layer is prepared by a second vacuum flash evaporation method.

[0187] By preparing the perovskite layer by vacuum flash evaporation, it is possible to effectively control the grain growth and surface morphology inside the perovskite layer, improve the film quality of the perovskite layer, and thereby improve the device efficiency of the perovskite battery.

[0188] In some embodiments, preparing the perovskite layer by the second vacuum flash evaporation method may include the following steps:

[0189] S210, coating a perovskite precursor solution on the hole transport layer to form a perovskite wet film;

[0190] S220, performing a second vacuum flash evaporation treatment on the perovskite wet film to flash evaporate the solvent in the perovskite precursor solution to form a perovskite mesophase film;

[0191] S230, annealing the perovskite intermediate phase film to form the perovskite layer.

[0192] When preparing perovskite cells, the traditional method is usually to use the anti-solvent method to prepare the perovskite layer. However, in the preparation process of perovskite cells, especially in the preparation process of tin-lead perovskite cells, the anti-solvent itself is not only highly toxic and pollutes the environment, but also depends heavily on the operating techniques of the experimenters. Uncontrollable human factors, such as the time and speed of dripping, will cause uneven crystallization quality of the perovskite film, poor device repeatability, and high cost, which is not conducive to commercial production. This seriously restricts the application of tin-lead perovskite cells.

[0193] In addition, the anti-solvent method is a rapid crystallization preparation method. Perovskite films are usually formed by rapid nucleation and crystallization from solutions at relatively low temperatures, which leads to the presence of many small grains stacked in the perovskite film, with a complex polycrystalline structure and a large number of grain boundaries. These grain boundaries are prone to serious non-radiative recombination, which in turn affects carrier transport, promotes ion migration, introduces deep energy level defects, and causes a decrease in the device efficiency and stability of the perovskite battery. And for tin-lead perovskite batteries, their crystallization speed is much faster than that of conventional pure lead-based perovskite batteries. Therefore, the tin-lead perovskite film prepared by the anti-solvent method will have relatively poorer film quality and relatively higher defect density, more serious non-radiative recombination, and worse charge transport, resulting in a greater decrease in the efficiency and stability of tin-lead perovskite battery devices. In addition, the perovskite film prepared by the anti-solvent method usually has a rough surface and a large number of pinholes inside the film, which will make the density of the perovskite film poor and increase the contact gap between the interface and the adjacent charge transport layer (such as the hole transport layer), affecting the transport of carriers and further reducing the device efficiency of the perovskite battery.

[0194] In the embodiment of the present application, the perovskite layer is prepared by vacuum flash evaporation, so that the solvent in the perovskite precursor solution can be quickly extracted, the nucleation and crystallization rate of the perovskite is delayed, and the average size of the grains in the perovskite layer is increased. At the same time, it is conducive to promoting the growth of grains through the thickness direction of the perovskite layer, improving the consistency and uniformity of grain growth, and reducing the mutual stacking between grains, thereby reducing the number of grain boundaries between grains, reducing the occurrence of non-radiative recombination at grain boundaries, improving the transmission efficiency of carriers, inhibiting ion migration, and reducing deep energy level defects, thereby improving the device efficiency and stability of the perovskite battery. In particular, when the perovskite layer is a tin-lead perovskite layer, the nucleation and crystallization rate of the tin-lead perovskite can be delayed to a greater extent, thereby improving the device efficiency and stability of the tin-lead perovskite battery to a greater extent.

[0195] In addition, since vacuum flash evaporation can quickly extract the solvent from the perovskite precursor solution, compared with the anti-solvent method, it can reduce the recombination of the solvent and the perovskite intermediate phase film, which is beneficial to reduce the number of pinholes in the perovskite layer and improve the density of the perovskite film. At the same time, it reduces the surface roughness of the perovskite layer, improves the surface flatness and smoothness, improves the overall quality of the perovskite layer, reduces the contact gap between the interface and the adjacent charge transport layer (such as the hole transport layer), improves the transport of carriers, and further improves the device efficiency of the perovskite battery.

[0196] In addition, the perovskite film prepared by vacuum flash evaporation eliminates the step of manually adding anti-solvent, avoiding the influence of anti-solvent atmosphere on perovskite film formation. The device efficiency is higher, the process is simpler, and it is suitable for application in large-scale production.

[0197] In some embodiments, the second vacuum flash treatment may be performed in an environment where the water and oxygen contents are both lower than 0.1 ppm.

[0198] It should be noted that ppm refers to the mass of water and oxygen as a percentage of the total mass of gases in the environment.

[0199] It should be noted that water and oxygen will react with the perovskite mesophase film and affect the film quality of the perovskite, so the above steps S210 to S230 can be performed in an environment where the water and oxygen content is less than 0.1 ppm. For example, it can be performed in a glove box with a nitrogen atmosphere.

[0200] Optionally, the second vacuum flash evaporation treatment can be performed in a nitrogen atmosphere, thereby reducing the impact of water and oxygen on the quality of perovskite film formation, improving the quality of the perovskite film, and further improving the device efficiency of the perovskite battery.

[0201] It can be understood that the perovskite film described in the present application is equivalent to the perovskite layer in the perovskite battery.

[0202] In some embodiments, the temperature of the second vacuum flash treatment is 15°C to 35°C. For example, the temperature of the first vacuum flash treatment can be 15°C, 20°C, 25°C, 30°C, 35°C or within a range of any of the above values. Optionally, the temperature of the second vacuum flash treatment is 18°C ​​to 22°C.

[0203] The temperature of the second vacuum flash treatment is within the above range, which is beneficial to reduce the generation and stacking of small grains inside the perovskite layer film, reduce the number of grain boundaries, reduce the roughness of the film surface, and improve the flatness of the film surface, thereby improving the device efficiency of the perovskite battery.

[0204] In some embodiments, the extraction rate of the second vacuum flash treatment is 10m 3 / h~30m 3 For example, the extraction rate of the second vacuum flash treatment can be 10m 3 / h,13m 3 / h,15m 3 / h,17m 3 / h,20m 3 / h,23m 3 / h,25m 3 / h, 27m 3 / h, 30m 3 / h or within the range of any of the above values. Optionally, the extraction rate of the second vacuum flash treatment is 15m 3 / h~30m 3 / h.

[0205] The extraction rate of the second vacuum flash evaporation treatment is within the above range, which is beneficial to improving the film formation quality of the perovskite layer and further improving the device efficiency of the perovskite battery.

[0206] It can be understood that the extraction rate and extraction time of the second vacuum flash treatment are related to the power of the second vacuum flash treatment and the equipment used to implement the second vacuum flash treatment. Among them, the power can be adjusted according to the internal capacity of the equipment and the actual preparation requirements, and thus the extraction rate and extraction time can also be adjusted accordingly.

[0207] In some embodiments, the extraction time of the first vacuum flash treatment is 10s to 180s. For example, the extraction time can be 10s, 50s, 90s, 130s, 170s, 180s or within a range of any of the above values. Optionally, the extraction time is 25s to 40s.

[0208] As a non-limiting example, the above steps S210 to S230 may be performed in a nitrogen glove box. Figure 4 As shown, in a nitrogen atmosphere, the perovskite wet film can be placed in a sealed container through an opening at one end of the sealed container, and a vacuum pump is connected to the other end of the container through the opening, and a second vacuum flash treatment can be performed through the container and the vacuum pump. That is, the nitrogen in the container and the solvent in the perovskite precursor solution can be quickly extracted by the vacuum pump, thereby forming a perovskite intermediate phase film. The perovskite intermediate phase film is then annealed to form a perovskite layer.

[0209] In some embodiments, the annealing temperature is 70°C to 130°C. For example, the annealing temperature can be 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C or within a range of any of the above values. Optionally, the annealing temperature is 100°C to 130°C.

[0210] In some embodiments, the annealing time of the annealing treatment is 5 min to 30 min. For example, the annealing time can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min or within the range of any of the above values. Optionally, the annealing time is 10 min to 20 min.

[0211] The annealing temperature and annealing time are within the above range, which is beneficial to further improve the film formation quality of the perovskite film, thereby further improving the device efficiency of the perovskite battery.

[0212] In some embodiments, the perovskite precursor solution comprises a compound ABX3 or A2CDX6, wherein the A ion is a monovalent cation, the B ion is a divalent cation, the C ion is a monovalent cation, the D ion is a trivalent cation, and the X ion is a monovalent anion.

[0213] In some embodiments, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of .

[0214] Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole.

[0215] Optionally, the A ions include organic amine ions and Cs + One or more of .

[0216] In some embodiments, the X ions include F-, Cl-, Br - and one or more of I-.

[0217] Optionally, the X ions include Cl - Br - and I - One or more of .

[0218] In some embodiments, the perovskite precursor solution comprises compound APb y Sn 1-y X3,0 <y<1。

[0219] In some embodiments, the method may further include step S30:

[0220] S30, preparing an electron transport layer between the perovskite layer and the second electrode layer.

[0221] In some embodiments, the preparation method of the electron transport layer is not limited, and can be prepared by conventional methods in the art, such as vacuum evaporation.

[0222] In a third aspect, the present application provides a photovoltaic module, which includes the perovskite cell described in the first aspect of the present application or the perovskite cell prepared by the method described in the second aspect of the present application.

[0223] It is understood that the photovoltaic module may only include the perovskite cell described in the first aspect of the present application, or the perovskite cell may be combined with other solar cells, for example, the perovskite cell may be combined with a silicon solar cell.

[0224] In a fourth aspect, the present application provides an electrical device comprising at least one of the perovskite cell described in the first aspect of the present application, the perovskite cell prepared by the method described in the second aspect of the present application, and the photovoltaic module described in the third aspect of the present application.

[0225] In some embodiments, the perovskite battery can be used as a power generation device of an electrical device. The type of the power generation device can include but is not limited to integrated power generation. The location of the power generation device can include but is not limited to the roof, back panel, etc. of a car.

[0226] Furthermore, the above-mentioned electrical devices may include mobile devices, such as mobile phones, laptop computers, etc., electric vehicles, electric trains, ships and satellites, power generation systems, etc., but are not limited thereto.

[0227] Fig.10 The electrical device is taken as an example. The electrical device is a car, and can further be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0228] As another example, the electric device may be a mobile phone, a tablet computer, a laptop computer, a calculator, etc.

[0229] As another example, the power-consuming device may be a wearable device, such as a watch.

[0230] Example

[0231] Below, some embodiments of the present application are described. The embodiments described below are exemplary, are only used to explain the present application, and cannot be construed as limiting the present application. In the embodiments, if the technology or conditions are not indicated, they are carried out according to the description above, or according to the technology or conditions described in the document in this area or according to the product specification. The reagents used or the instruments that do not indicate the manufacturer are conventional products that can be obtained commercially, or can be synthesized in a conventional manner by commercially available products.

[0232] In the following embodiments, "room temperature" refers to 20°C to 30°C, and further, may be 25°C.

[0233] Example 1

[0234] (1) Preparation of the first electrode

[0235] Take a 5cm×5cm FTO conductive glass, leave an insulating area after laser etching, use deionized water, detergent, ethanol, isopropanol, acetone, ethanol, deionized water for 20 minutes, blow dry with N2 and perform UV ozone cleaning for 15 minutes, and use it as the first electrode for standby.

[0236] (2) Preparation of hole transport layer

[0237] ① Prepare a PEDOT:PSS aqueous solution (mass concentration of 1.7 wt%), take 2 mL of the aqueous solution, and filter it through a filter with a pore size of 0.45 μm. Take 200 μL of the filtered aqueous solution and spin-coat it onto the conductive glass in step (1) using a single-step spin coating method at 4000 rpm / min for 30 seconds.

[0238] ② After the spin coating, the conductive glass coated with PEDOT:PSS is placed in a sealed container (vacuum pump model rv12) in Figure (4), and the surface moisture is extracted by vacuum flash evaporation to prepare a hole transport layer with a thickness of about 14nm. The vacuum flash evaporation temperature is 25℃, the power is 600W, the extraction rate is 60g / h, and the extraction time is 60s.

[0239] (3) Preparation of perovskite layer

[0240] ① Mix methylamino iodide, methylamine iodide, lead iodide, stannous iodide, and stannous fluoride in a molar ratio of 0.7:0.3:0.4:0.6:0.05, and then dissolve them in a solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 2:1 to obtain a perovskite precursor solution (molar concentration of 1.8 mol / L).

[0241] ② Place the hole transport layer obtained in step (2) into a nitrogen glove box, and control the water and oxygen content in the glove box to be less than 0.1 ppm. Use a pipette to transfer 100 μL of the perovskite precursor solution onto the hole transport layer, and use a single-step spin coating method to prepare a perovskite wet film at a spin coating speed of 4000 rpm / min and a spin coating time of 30 s.

[0242] ③ Place the sealed container in Figure (4) into a nitrogen glove box, place the prepared perovskite wet film into the sealed container, and remove excess solvent by vacuum flash evaporation to obtain a perovskite mesophase film. The vacuum flash evaporation temperature is 25°C, the power is 600W, the extraction rate is 70g / h, and the extraction time is 30s.

[0243] ④ The perovskite intermediate phase film was placed on a hot plate at 100°C for 10 minutes for annealing to prepare a perovskite layer (component: FA 0.7 MA 0.3 Pb 0.4 Sn 0.6 I3), the thickness of which is about 900nm.

[0244] (4) Preparation of electron transport layer

[0245] The prepared perovskite layer was placed in a vacuum thermal evaporation device and evacuated to 4×10 -4 Pa, deposited 25nmC60 , 6nm BCP (bathocuproine) is used to obtain the electron transport layer.

[0246] (5) Preparation of the Second Electrode

[0247] A Cu counter electrode is deposited on the electron transport layer using a thermal evaporation method using a mask with a specific pattern to form a second electrode with a thickness of about 100 nm to obtain a perovskite cell.

[0248] Embodiments 2 to 21

[0249] The preparation method of the perovskite battery is similar to that of Example 1, except that the relevant parameters of the perovskite and its preparation process are adjusted, and the specific parameters are shown in Tables 1 to 2 below, where " / " indicates that the corresponding parameter does not exist.

[0250] Comparative Example 1

[0251] The preparation method of the perovskite cell is similar to that of Example 1, except that an annealing treatment (annealing temperature is 150° C., annealing time is 10 min) is used instead of the vacuum flash evaporation method in step (2)-② to prepare the hole transport layer.

[0252] Comparative Example 2

[0253] The preparation method of the perovskite battery is similar to that of Example 1, except that: an annealing treatment (annealing temperature is 150° C., annealing time is 10 min) is used instead of the vacuum flash evaporation method in step (2)-② to prepare the hole transport layer; at the same time, an anti-solvent method is used instead of the vacuum flash evaporation method in step (3) to prepare the perovskite intermediate phase film. The specific preparation process is as follows:

[0254] The hole transport layer obtained in step (2) was placed in a nitrogen glove box, and the water and oxygen content in the glove box was controlled to be less than 0.1 ppm. 100 μL of the perovskite precursor solution was pipetted with a pipette and dropped on the hole transport layer, and the perovskite wet film was prepared by a two-step spin coating method: the first step was a spin coating speed of 2000 rpm / min and a spin coating time of 10 s; the second step was a spin coating speed of 5000 rpm / min and a spin coating time of 50 s. 400 μL of chlorobenzene was added 20 s before the end to obtain a perovskite intermediate phase film.

[0255] Table 1

[0256]

[0257] Table 2

[0258]

[0259]

[0260] In addition, relevant performance tests were performed on the perovskite cells in Examples 1 to 21 and Comparative Examples 1 to 2, and the results are shown in Table 3 below.

[0261] Test Method

[0262] (1) Surface morphology test

[0263] The surface morphology of the hole transport layer and the perovskite layer was tested using a scanning electron microscope (model: Hitachi, HD-2700) and an atomic force microscope (model: Oxford Instruments, MFP-3D-Origin).

[0264] (2) Photoelectric conversion efficiency test

[0265] At room temperature and pressure, under standard simulated sunlight (AM 1.5G, 100mW / cm 2 ) to test the battery performance and obtain the IV curve (volt-ampere characteristic curve). According to the IV curve and the data fed back by the test equipment (four-channel digital source meter, Keithley2440), the short-circuit current density Jsc (unit: mA / cm 2 ), open circuit voltage Voc (unit V), maximum light output current Jmpp (unit mA) and maximum light output voltage Vmpp (unit V).

[0266] The fill factor FF of the battery can be calculated by the formula FF = Jsc × Voc / (Jmpp × Vmpp), unit %. The photoelectric conversion efficiency PCE of the battery can be calculated by the formula PCE = Jsc × Voc × FF / Pw, unit %; Pw represents the input power, unit mW.

[0267] “Normal temperature and pressure” refers to normal pressure: the pressure is one atmosphere when the temperature is 25°C; normal temperature refers to 20°C to 30°C, and further, it can be 25°C.

[0268] (3) Stability test

[0269] The stability test conditions of the perovskite battery are: stored in a nitrogen glove box at a constant temperature of 25°C and protected from light. The photocurrent density-voltage curve of the battery device is tested at regular intervals and the corresponding photoelectric conversion efficiency is normalized to obtain the photovoltaic efficiency decay curve of the perovskite battery.

[0270] Maximum power point (MPP) tracking was used under simulated 1 sun illumination and the test was stopped when the cell efficiency dropped to 90% of its initial PCE.

[0271] Table 3

[0272] Photoelectric conversion efficiency (%) Stability (h) Example 1 18.35 1550 Example 2 18.00 1445 Example 3 18.23 1500 Example 4 17.80 1335 Example 5 17.64 1247 Example 6 17.85 1480 Example 7 18.26 1535 Example 8 17.45 1450 Example 9 18.30 1500 Example 10 18.25 1480 Embodiment 11 18.00 1400 Example 12 17.50 1330 Example 13 17.1 1415 Embodiment 14 18.22 1510 Embodiment 15 17.5 1432 Example 16 18.22 1495 Embodiment 17 18.05 1460 Embodiment 18 17.20 1380 Embodiment 19 17.05 1350 Embodiment 20 17.00 1300 Embodiment 21 16.50 1280 Comparative Example 1 15.25 1210 Comparative Example 2 14.50 1080

[0273] In Table 3, by comparing Examples 1 to 21 with the comparative example, it can be seen that the photoelectric conversion efficiency and stability of the perovskite cell obtained by preparing the hole transport layer or the perovskite layer by the vacuum flash evaporation method in the present application are significantly higher than those of the comparative example, indicating that the vacuum flash evaporation method can improve the photoelectric conversion efficiency and stability of the cell.

[0274] In addition, from Figure 5 It can be seen that the surface of the hole transport layer prepared by annealing treatment in Comparative Example 1 (Figure (a)) is very rough, and sometimes there are a large number of holes; the surface roughness of the hole transport layer prepared by vacuum flash evaporation in Example 1 (Figure (b)) is significantly reduced, and the surface of the hole transport layer is smoother.

[0275] from Figure 7 It can be seen that the surface of the perovskite layer prepared by vacuum flash evaporation in Example 1 (Figure (b)) is smooth and flat, without obvious pinholes and defects, forming a denser and more uniform polycrystalline film; while the surface of the perovskite layer prepared by anti-solvent in Example 23 (Figure (a)) is rough and has a large number of pinholes.

[0276] from Figure 8 and Fig. 9 It can be seen that Example 1 ( Fig. 9 ) in which the perovskite layer prepared by the vacuum flash evaporation method grows through the thickness direction, and the grains evenly expand to several microns along the base and vertical directions, and the interior of the perovskite layer presents a compact and dense morphology; while Example 18 ( Figure 8 ) in the perovskite layer prepared by the anti-solvent method, small grains are stacked on top of each other (size is between 200nm and 400nm), and there are a large number of grain boundaries, where serious non-radiative recombination is prone to occur, resulting in a decrease in the photoelectric conversion efficiency and stability of the perovskite battery.

[0277] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0278] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples. Within the scope of the technical solution of the present application, the embodiments that have the same structure as the technical idea and play the same effect are all included in the technical scope of the present application. The above-mentioned embodiments only express several embodiments of the present application, and the description is relatively detailed, but it cannot be understood as a limitation on the scope of the patent. In addition, without departing from the scope of the subject matter of the present application, various deformations that can be thought of by those skilled in the art and other methods of combining and constructing some of the constituent elements in the embodiments are also included in the scope of the present application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several deformations and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the attached claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. A perovskite battery, characterized in that: It comprises a first electrode layer, a hole transport layer, a perovskite layer and a second electrode layer which are stacked in sequence, wherein the surface roughness of the hole transport layer is Ra1, and Ra1<3nm.

2. The perovskite battery according to claim 1, characterized in that: The surface roughness Ra1 of the hole transport layer satisfies: <Ra1≤1.5nm。 3. The perovskite battery according to claim 1 or 2, characterized in that: The number of pinholes per unit area of ​​the hole transport layer is n1, 0≤n1≤2, and can be optionally 0≤n1≤1.

4. The perovskite battery according to claim 1 or 2, characterized in that: The perovskite layer comprises crystal grains distributed throughout the thickness direction of the perovskite layer; Optionally, the average size of the grains is 600nm to 800nm, and optionally 650nm to 750nm.

5. The perovskite battery according to claim 1 or 2, characterized in that: The surface roughness of the perovskite layer is Ra2, Ra2<3nm, which can be 0 <Ra2≤1.5nm。 6. The perovskite battery according to claim 1 or 2, characterized in that: The number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤2, and can be optionally 0≤n2≤1.

7. The perovskite battery according to claim 1 or 2, characterized in that: Satisfy at least one of the following conditions: (1) The thickness of the hole transport layer is 10 nm to 30 nm, and can be 15 nm to 25 nm; (2) The thickness of the perovskite layer is 700 nm to 1200 nm, and can be optionally 800 nm to 1000 nm.

8. The perovskite battery according to claim 1 or 2, characterized in that: Satisfy at least one of the following conditions: (1) The perovskite layer comprises a compound ABX3 or A2CDX6, wherein the A ion is a monovalent cation, the B ion is a divalent cation, the C ion is a monovalent cation, the D ion is a trivalent cation, and the X ion is a monovalent anion; Optionally, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of; Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole; Optionally, the A ions include organic amine ions and Cs + One or more of; Optionally, the B ions include Pb 2+ Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ , Fe 2+ 、Co 2+ , Cu 2+ and Ni 2+ One or more of; Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following: Optionally, the C ions include Cs + 、Ag + , K + And Ru + One or more of; Optionally, the D ions include Bi 3+ 、Ni 3+ , Fe 3+ and Cu 3+ One or more of; Optionally, the X ions include F - , Cl - Br - and I - One or more of; Optionally, the X ions include Cl - , Br- and I - One or more of; Optionally, the perovskite layer comprises compound APb y Sn 1-y X3,0 <y<1; (2) The perovskite cell further includes an electron transport layer, which is disposed between the perovskite layer and the second electrode layer.

9. A method for preparing a perovskite battery, characterized in that: include: A hole transport layer is prepared on the first electrode layer, wherein the surface roughness of the hole transport layer is Ra1, Ra1<3nm; A perovskite layer and a second electrode layer are sequentially stacked on the hole transport layer to obtain a perovskite cell.

10. The method according to claim 9, characterized in that The method of preparing a hole transport layer on the first electrode layer comprises: Applying a solution of a hole transport material on the first electrode layer to form a wet film of the hole transport material; Performing the first vacuum flash evaporation treatment on the wet film of the hole transport material to flash evaporate the solvent in the hole transport material solution to form the hole transport layer; Optionally, the first vacuum flash treatment is performed in an air atmosphere.

11. The method according to claim 10, characterized in that Satisfy at least one of the following conditions: (1) The temperature of the first vacuum flash treatment is 15°C to 35°C; (2) The extraction rate of the first vacuum flash treatment is 5m 3 / h~20m 3 / h; (3) The hole transport material includes one or more of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, polytriarylamine, poly-3,4-ethylenedioxythiophene: polystyrene sulfonate, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, and N-(4-phenylamino)carbazole-spirobifluorene. Optionally, it may be poly (3,4-ethylenedioxythiophene):polystyrene sulfonate.

12. The method according to any one of claims 9 to 11, characterized in that: The preparation of the perovskite layer comprises: coating a perovskite precursor solution on the hole transport layer to form a perovskite wet film; Performing a second vacuum flash evaporation treatment on the perovskite wet film to flash evaporate the solvent in the perovskite precursor solution to form a perovskite mesophase film; Annealing the perovskite intermediate phase film to form the perovskite layer; Optionally, the second vacuum flash treatment is performed in a nitrogen atmosphere.

13. The method according to claim 12, characterized in that Satisfy at least one of the following conditions: (1) The temperature of the second vacuum flash treatment is 15°C to 35°C, and can be optionally 18°C ​​to 22°C; (2) The extraction rate of the second vacuum flash treatment is 10m 3 / h~30m 3 / h; optional: 15m 3 / h~30m 3 / h; (3) The annealing temperature is 70°C to 130°C, and can be 100°C to 130°C; (4) The annealing time of the annealing treatment is 5 min to 30 min, and can be optionally 10 min to 20 min; (5) The perovskite precursor solution contains a compound ABX3 or A2CDX6, wherein the A ion is a monovalent cation, the B ion is a divalent cation, the C ion is a monovalent cation, the D ion is a trivalent cation, and the X ion is a monovalent anion; Optionally, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of; Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole; Optionally, the A ions include organic amine ions and Cs + One or more of; Optionally, the B ions include Pb 2+ Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ , Fe 2+ 、Co 2+ , Cu 2+ and Ni 2+ One or more of; Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following: Optionally, the C ions include Cs + 、Ag + , K + And Ru + One or more of; Optionally, the D ions include Bi 3+ 、Ni 3+ , Fe 3+ and Cu 3+ One or more of; Optionally, the X ions include F - , Cl - , Br- and I-; Optionally, the X ions include Cl-, Br- and I - One or more of; Optionally, the perovskite precursor solution comprises compound APb y Sn 1-y X3,0 <y<1。 14. The method according to any one of claims 9 to 13, characterized in that: Also includes: An electron transport layer is prepared between the perovskite layer and the second electrode layer.

15. A photovoltaic module, characterized in that: A perovskite battery comprising the perovskite battery according to any one of claims 1 to 8 or a perovskite battery prepared by the method according to any one of claims 9 to 14.

16. An electrical device, characterized in that: It comprises at least one of the perovskite cell according to any one of claims 1 to 8, the perovskite cell prepared by the method according to any one of claims 9 to 14, and the photovoltaic module according to claim 15.

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