Perovskite cell and preparation method therefor, and electric apparatus

Abstract

The present application relates to a perovskite cell and a preparation method therefor, and an electric apparatus. The perovskite cell comprises a first electrode layer, a hole transport layer, a perovskite layer and a second electrode layer, which are arranged in a sequentially stacked manner, wherein the surface roughness of the hole transport layer is Ra1, and Ra1<3nm.

Description

Perovskite battery, preparation method thereof, and power-using device

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202310980482.0, filed on August 4, 2023, entitled “Perovskite battery, preparation method thereof, and electrical device”, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the technical field of solar cells, and in particular to a perovskite cell, a preparation method thereof, and an electrical device thereof. Background Art

[0004] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0005] Perovskite solar cells (PSCs) are devices that convert solar energy into electrical energy using the photoelectric conversion mechanism of perovskite crystal materials. They are currently the third generation of solar cells and have been extensively researched in recent years due to their high photoelectric conversion efficiency, simple manufacturing process, and low production cost. Despite this, the commercialization and large-scale application of PSCs is still some distance away. Improving the device efficiency of PSCs is a key issue that needs to be addressed.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides a perovskite battery and its preparation method and power-consuming device. By improving the perovskite battery, the device efficiency of the perovskite battery can be improved.

[0008] In a first aspect, the present application provides a perovskite cell comprising 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<3 nanometers (nm).

[0009] In the above-mentioned perovskite cell provided in the present application, when the surface roughness Ra1 of the hole transport layer is less than 3 nm, 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, thereby improving the transmission efficiency of hole carriers and thus improving the device efficiency of the perovskite cell.

[0010] In some embodiments, the surface roughness Ra1 of the hole transport layer satisfies: 0 <Ra1≤1.5nm。

[0011] 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 transport efficiency of hole carriers, and thus further improve the device efficiency of the perovskite battery.

[0012] In some embodiments, the number of pinholes per unit area of ​​the hole transport layer is n1, 0≤n1≤2, and optionally 0≤n1≤1.

[0013] 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 adjacent perovskite layer (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.

[0014] In some embodiments, the perovskite layer comprises crystal grains distributed throughout the thickness direction of the perovskite layer;

[0015] Optionally, the average size of the grains is 600 nm to 800 nm, or optionally 650 nm to 750 nm.

[0016] The perovskite layer of the present application contains grains distributed throughout the thickness direction of the perovskite layer, which is beneficial to reducing the stacking of grains, thereby reducing the number of grain boundaries generated by the 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.

[0017] In some embodiments, the surface roughness of the perovskite layer is Ra2, Ra2<3nm, which can be 0 <Ra2≤1.5nm。

[0018] When the surface roughness Ra2 of the perovskite layer is less than 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), improve the carrier transport efficiency, and thus improve the device efficiency of the perovskite battery.

[0019] In some embodiments, the number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤2, and optionally 0≤n2≤1.

[0020] 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.

[0021] In some embodiments, the perovskite cell satisfies at least one of the following conditions:

[0022] (1) The thickness of the hole transport layer is 10 nm to 30 nm, and can be optionally 15 nm to 25 nm;

[0023] (2) The thickness of the perovskite layer is 700 nm to 1200 nm, and can be optionally 800 nm to 1000 nm.

[0024] The thickness of the perovskite layer is within the above range, which is conducive to promoting the transport and collection of carriers, thereby promoting the improvement of the efficiency of perovskite battery devices.

[0025] In some embodiments, the perovskite cell satisfies at least one of the following conditions:

[0026] (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;

[0027] Optionally, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of;

[0028] Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, amidino and imidazolyl groups;

[0029] Optionally, the A ions include organic amine ions and Cs + One or more of;

[0030] 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;

[0031] Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following:

[0032] Optionally, the C ions include Cs + 、Ag + , K + Ru + One or more of the following;

[0033] Optionally, the D ions include Bi 3+ 、Ni 3+ 、Fe 3+ and Cu 3+ One or more of;

[0034] Optionally, the X ions include F - 、Cl - Br - and I - One or more of;

[0035] Optionally, the X ions include Cl - Br - and I - One or more of;

[0036] Optionally, the perovskite layer comprises compound APb y Sn 1-y X3,0 <y<1;

[0037] (2) The perovskite battery further includes an electron transport layer, which is disposed between the perovskite layer and the second electrode layer.

[0038] In a second aspect, the present application provides a method for preparing a perovskite battery, which comprises:

[0039] A hole transport layer is prepared on the first electrode layer, wherein the surface roughness of the hole transport layer is Ra1, and Ra1 is less than 3 nm;

[0040] A perovskite layer and a second electrode layer are sequentially stacked on the hole transport layer to obtain a perovskite cell.

[0041] 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 adjacent to it, improve the transmission efficiency of hole carriers, and thus improve the device efficiency of the perovskite cell.

[0042] In some embodiments, the step of preparing a hole transport layer on the first electrode layer comprises:

[0043] preparing the hole transport layer on the first electrode layer by a first vacuum flash evaporation method;

[0044] Optionally, preparing the hole transport layer by the first vacuum flash evaporation method includes:

[0045] coating a solution of a hole transport material on the first electrode layer to form a wet film of the hole transport material;

[0046] 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;

[0047] Optionally, the first vacuum flash evaporation treatment is performed in an air atmosphere.

[0048] 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.

[0049] In some embodiments, the method satisfies at least one of the following conditions:

[0050] (1) The temperature of the first vacuum flash treatment is 15 degrees Celsius (°C) to 35°C;

[0051] (2) The extraction rate of the first vacuum flash treatment is 5 cubic meters per hour (m 3 / h) to 20m 3 / h;

[0052] (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.

[0053] Optional is poly (3,4-ethylenedioxythiophene):polystyrene sulfonate.

[0054] The temperature of the first vacuum flash evaporation treatment is within the above range, which is beneficial to reducing the generation of small cracks or wrinkles inside and on the surface of the hole transport layer film, reducing the roughness of the film surface, and improving the flatness of the film surface, thereby improving the device efficiency of the perovskite battery.

[0055] In some embodiments, the perovskite layer is prepared by a second vacuum flash evaporation method.

[0056] In some embodiments, preparing the perovskite layer by the second vacuum flash evaporation method includes:

[0057] coating a perovskite precursor solution on the hole transport layer to form a perovskite wet film;

[0058] 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 thin film;

[0059] annealing the perovskite mesophase thin film to form the perovskite layer;

[0060] Optionally, the second vacuum flash treatment is performed in a nitrogen atmosphere.

[0061] By preparing the perovskite layer through 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 thus improve the device efficiency of the perovskite battery.

[0062] In some embodiments, the method satisfies at least one of the following conditions:

[0063] (1) The temperature of the second vacuum flash treatment is 15°C to 35°C, and can be optionally 18°C ​​to 22°C;

[0064] (2) The extraction rate of the second vacuum flash treatment is 10m 3 / h to 30m 3 / h; 15m / h is optional 3 / h to 30m 3 / h;

[0065] (3) The annealing temperature is 70°C to 130°C, and can be 100°C to 130°C;

[0066] (4) The annealing time of the annealing treatment is 5 minutes (min) to 30 minutes, and can be optionally 10 minutes to 20 minutes;

[0067] (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;

[0068] Optionally, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of;

[0069] Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, amidino and imidazolyl groups;

[0070] Optionally, the A ions include organic amine ions and Cs + One or more of;

[0071] 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;

[0072] Optionally, the B ions include Pb 2+ and Sn 2+ One or both of the following:

[0073] Optionally, the C ions include Cs + 、Ag + , K + Ru + One or more of the following;

[0074] Optionally, the D ions include Bi 3+ 、Ni 3+ 、Fe 3+ and Cu 3+ One or more of;

[0075] Optionally, the X ions include F - 、Cl - Br - and I - One or more of;

[0076] Optionally, the X ions include Cl - Br - and I - One or more of;

[0077] Optionally, the perovskite precursor solution contains compound APb y Sn 1-y X3,0 <y<1。

[0078] 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 delayed, and the average size of the grains in the perovskite layer can be increased. At the same time, it is beneficial to promote the growth of grains along the thickness direction of the perovskite layer, improve the consistency and uniformity of grain growth, and reduce the 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.

[0079] In some embodiments, the method further comprises: preparing an electron transport layer between the perovskite layer and the second electrode layer.

[0080] In a third aspect, the present application provides a stacked battery, comprising the perovskite battery described in the first aspect of the present application or the perovskite battery prepared by the method described in the second aspect of the present application.

[0081] In a fourth aspect, the present application provides a photovoltaic module 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 stacked cell described in the third aspect of the present application.

[0082] In a fifth 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, the stacked cell described in the third aspect of the present application, and the photovoltaic module described in the fourth aspect of the present application.

[0083] 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

[0084] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive work. In the drawings:

[0085] FIG1 is a schematic diagram of a perovskite cell according to an embodiment of the present application.

[0086] FIG2 is a schematic diagram of a perovskite cell according to an embodiment of the present application.

[0087] FIG3 is a schematic diagram of a perovskite cell according to an embodiment of the present application.

[0088] FIG4 is a schematic diagram of an apparatus for performing vacuum flash evaporation according to an embodiment of the present application.

[0089] FIG5 is a surface morphology of the hole transport layer in the perovskite battery of Example 1 (FIG. (b)) and Comparative Example 1 (FIG. (a)).

[0090] FIG6 is a cross-sectional morphology of the hole transport layer in the perovskite battery of Example 1 at different magnifications.

[0091] FIG7 is a surface morphology of the perovskite layer in the perovskite cells of Example 1 (Figure (b)) and Example 18 (Figure (a)).

[0092] FIG8 is a cross-sectional morphology of the perovskite layer in the perovskite cell of Example 18 at different magnifications.

[0093] FIG9 is a cross-sectional morphology of the perovskite layer in the perovskite cell of Example 1 at different magnifications.

[0094] FIG10 is a schematic diagram of an electrical device using a perovskite cell as a power source according to an embodiment of the present application.

[0095] Reference numerals: 10 substrate layer; 20 first electrode layer; 30 hole transport layer; 40 perovskite layer; 50 electron transport layer; 60 second electrode layer. DETAILED DESCRIPTION

[0096] Below, some embodiments of the perovskite cell, its preparation method, and the electrical device of the present application are described in detail, with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary length in the following description and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0097] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and 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 special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this 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 all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for a combination of these values. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0098] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0099] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating 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), indicating 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.

[0100] 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.

[0101] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0102] 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 construed as indicating or implying relative importance or quantity, nor can they be construed 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 enumerative description and should be understood not to constitute a closed limitation on quantity.

[0103] In a perovskite solar cell, especially in a narrow-bandgap tin-lead perovskite solar cell, for the 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 thus the device efficiency of the perovskite solar cell.

[0104] Based on this, in a first aspect, the present application provides a perovskite solar cell, as shown in Figure 1, 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.

[0105] In the perovskite solar cell provided by the present application, when the surface roughness Ra1 of the hole transport layer < 3 nm, the flatness and smoothness of its film surface are relatively high. In this way, the contact gaps between the hole transport layer and the perovskite layer adjacent to it 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.

[0106] 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.

[0107] 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 relatively far from the first electrode layer and relatively close to the perovskite layer.

[0108] 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.

[0109] In some embodiments, the number of pinholes per unit area of ​​the hole transport layer is n1, where 0≤n1≤2. Alternatively, the number of pinholes per unit area of ​​the hole transport layer is 0≤n1≤1.

[0110] 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 adjacent perovskite layer (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.

[0111] In some embodiments, the hole transport layer has a thickness of 10 nm to 30 nm. For example, the hole transport layer can have a thickness of 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, or any range thereof. Alternatively, the hole transport layer has a thickness of 15 nm to 25 nm.

[0112] The thickness of the hole transport layer is within the above range, which is conducive to promoting the transport and collection of hole carriers, thereby promoting the improvement of the efficiency of perovskite battery devices.

[0113] In some embodiments, the perovskite layer comprises crystal grains distributed throughout the thickness direction of the perovskite layer (see FIG. 9 ).

[0114] 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 through 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.

[0115] In traditional perovskite layers, the grain size is usually small, so the grains are stacked and distributed with each other (see Figure 8). This stacking of grains will produce a large number of grain boundaries. 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 the device efficiency and stability of the perovskite battery to decrease. The perovskite layer of the present application contains grains distributed throughout the thickness direction of the perovskite layer, which is conducive to reducing the stacking of grains, thereby reducing the number of grain boundaries generated by the stacking of grains, reducing the occurrence of non-radiative recombination at grain boundaries, improving carrier transport efficiency, inhibiting ion migration, and reducing deep energy level defects, thereby improving the device efficiency and stability of the perovskite battery.

[0116] In some embodiments, the average size of the grains is 600 nm to 800 nm. For example, the average size of the grains can be 600 nm, 620 nm, 640 nm, 660 nm, 680 nm, 700 nm, 720 nm, 740 nm, 760 nm, 780 nm, 800 nm, or any range thereof. Alternatively, the average size of the grains is 650 nm to 750 nm.

[0117] The average grain size is well known in the art and can be measured using methods known in the art. For example, it can be measured using a scanning electron microscope. During measurement, the grains can be observed and measured on a unit area of ​​the perovskite layer. For example, at a magnification of 30K, a unit area (2.5 μm × 2.5 μm) of the surface of the perovskite layer is scanned. The maximum radius of several (e.g., 10) grains within this area is measured, and the average value is used to obtain the average grain size.

[0118] The average size of the grains 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.

[0119] In some embodiments, the surface roughness of the perovskite layer is Ra2, Ra2<3nm, for example, Ra2 can 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 consisting of any of the above values. Optionally, 0 <Ra2≤1.5nm。

[0120] 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.

[0121] When the surface roughness Ra2 of the perovskite layer is less than 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), improve the carrier transport efficiency, and thus improve the device efficiency of the perovskite battery.

[0122] In some embodiments, the number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤2. Alternatively, 0≤n2≤1.

[0123] 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.

[0124] In some embodiments, the perovskite layer has a thickness of 700 nm to 1200 nm. For example, the perovskite layer can have a thickness of 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, or any range thereof. Alternatively, the perovskite layer has a thickness of 800 nm to 1000 nm.

[0125] The thickness of the perovskite layer is within the above range, which is conducive to promoting the transport and collection of carriers, thereby promoting the improvement of the efficiency of perovskite battery devices.

[0126] In the present application, the surface roughness of the hole transport layer and the perovskite layer is well known in the art and can be tested using methods known in the art. For example, the surface roughness of the hole transport layer and the perovskite layer can be characterized and tested using atomic force microscopy (AFM).

[0127] In this application, the number of pinholes per unit area of ​​the hole transport layer and the perovskite layer has a meaning well known in the art and can be measured using 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 a scanning electron microscope. For example, at a magnification of 30K, an area per unit area (2.5 μm × 2.5 μm) of the surface of the perovskite layer is scanned to observe and count the number of pinholes.

[0128] In this application, the thickness of the hole transport layer and the perovskite layer has a well-known meaning in the art and can be measured using methods known in the art, for example, using a micrometer.

[0129] 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.

[0130] In some embodiments, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of .

[0131] In some embodiments, the organic cation includes at least one of a methylamino group, an ethylamino group, a propylamino group, a butylamino group, a pentylamino group, a hexylamino group, a carbamimidoyl group, and an imidazolyl group.

[0132] In some embodiments, the A ions include organic amine ions and Cs + One or more of .

[0133] 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 .

[0134] Optionally, the B ions include Pb 2+ and Sn 2+ One or both of .

[0135] In some embodiments, the C ions include Cs + 、Ag + , K + and Ru + One or more of.

[0136] In some embodiments, the D ions include Bi 3+ 、Ni 3+ 、Fe 3+ and Cu 3+ One or more of .

[0137] In some embodiments, the X ions include F - 、Cl - Br - and I - One or more of .

[0138] Optionally, the X ions include Cl - Br - and I - One or more of .

[0139] Optionally, the perovskite layer comprises compound APb y Sn 1-y X3,0 <y<1。

[0140] In some embodiments, the perovskite cell of the present application may be a tin-lead perovskite cell. The perovskite layer comprises the compound APb y Sn 1-y X3,0 <y<1。

[0141] In some embodiments, as shown in FIG. 2 , 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 .

[0142] In some embodiments, as shown in FIG2 , the perovskite cell includes 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 stacked in sequence. Furthermore, the perovskite cell may be either an inverted pin cell or a regular nip cell.

[0143] 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.

[0144] 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.

[0145] In some embodiments, the second electrode comprises a conductive material, and further, the conductive material can 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 can 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 foregoing elements. The conductive material can include a conductive oxide, and further, the conductive material can be a conductive oxide; non-limiting examples of conductive oxides can include one or more of FTO, ITO, IWO, AZO, etc.

[0146] In some embodiments, the perovskite cell is any one of an inverted pin cell and a formal nip cell.

[0147] The perovskite cells provided in this application may include formal and trans types.

[0148] 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.

[0149] For the trans type, the perovskite cell includes 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.

[0150] The perovskite layer described in this application is the light-absorbing layer in the perovskite cell.

[0151] When a perovskite cell is operating, after the light-absorbing layer is exposed to light, the internal electrons gain energy and break free from the constraints of the light-absorbing layer to form negatively charged electron carriers. At the same time, positively charged hole carriers are formed, thereby forming electron-hole pairs. The free electrons and free holes are transmitted in opposite directions through the corresponding transport layers, causing the electrons and holes to flow, forming an external current and realizing the conversion of light energy into electrical energy. Furthermore, after the perovskite layer absorbs photons, it is stimulated to produce electron-hole pairs. The electron-hole pairs 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 a photocurrent in the perovskite cell circuit.

[0152] The electron transport layer can extract and transport electron carriers and block the passage of free holes.

[0153] The hole transport layer can extract and transport hole carriers and block the passage of free electrons.

[0154] 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 through the electron transport layer, and the other serves as a negative electrode and can collect hole carriers transmitted through the hole transport layer.

[0155] 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 with triptycene as the core (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4- aniline) 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 magnesium (Mg), nickel (Ni), cadmium (Cd), zinc (Zn), indium (In), lead (Pb), molybdenum (Mo), tungsten (W), antimony (Sb), bismuth (Bi), copper (Cu), mercury (Hg), titanium (Ti), silver (Ag), manganese (Mn), iron (Fe), vanadium (V), tin (Sn), zirconium (Zr), strontium (Sr), gallium (Ga) and chromium (Cr).

[0156] 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.

[0157] Optionally, the hole transport layer comprises poly (3,4-ethylenedioxythiophene):polystyrene sulfonate).

[0158] In some embodiments, the perovskite cell may further include a substrate layer.

[0159] In some embodiments, as shown in FIG3 , the perovskite cell includes the following structure 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. The flexible substrate may include one or more materials selected from polyethylene terephthalate, polyimide, polyethylene, polypropylene, polystyrene, and polyethylene naphthalate. Optionally, the first electrode layer is a transparent electrode layer for light incidence.

[0160] In some embodiments, the perovskite cell comprises the following structure, arranged in sequence: a substrate layer (glass or flexible), 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 flexible substrate is described above.

[0161] The substrate layer involved in the implementation manner or examples of the present application may be, but is not limited to, a glass substrate or a flexible substrate.

[0162] In some embodiments, the substrate layer is a flexible substrate layer. Furthermore, the substrate layer may be made of, for example (but not limited to), an organic polymer material, and may be made of one or more of the following materials mixed in different proportions: including but not limited to polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), and the like.

[0163] 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.

[0164] It is understood that the structure of the perovskite cell involved in this application may not be limited to the structural layers listed above. Other functional layers, such as buffer layers, may also be introduced as needed. In some embodiments, the perovskite cell may be provided with a buffer layer with a suitable energy level, which may play one or more roles in reducing the energy level barrier, promoting energy level matching, improving carrier extraction efficiency, passivating interface defect states, protecting the light absorption layer, inhibiting water molecules and oxygen from oxidative decomposition of the cell, improving photoelectric conversion efficiency, and improving the stability of the perovskite cell. Depending on the location of the buffer layer, the types of buffer layers may include four types: 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. Materials that can be used for the buffer layer in the perovskite cell may include, but are not limited to: Cu2O (cuprous oxide), NiO (nickel oxide), AZO (aluminum-doped zinc oxide), TiO2 (titanium oxide), etc.

[0165] 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:

[0166] 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;

[0167] S20, preparing a perovskite layer and a second electrode layer in sequence on the hole transport layer to obtain a perovskite battery.

[0168] 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 adjacent to it, improve the transmission efficiency of hole carriers, and thus improve the device efficiency of the perovskite cell.

[0169] 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.

[0170] It is understood that the principle of vacuum flash evaporation described herein involves the process of superheating a liquid in a vacuum environment and rapidly evaporating it into vapor. During vacuum flash evaporation, the pressure of the environment surrounding the liquid droplet drops rapidly, causing the entire droplet to become superheated. Flash evaporation then occurs not only on the surface of the droplet but also within the droplet.

[0171] When preparing perovskite cells, the traditional method is usually to use a coating + annealing method to prepare the hole transport layer. That is, first, a solution of the hole transport material needs to be coated on an 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 is not only time-consuming, but more importantly, during annealing, the hole transport layer film 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. In addition, a large number of pinholes will be generated inside the film, which increases the contact gap between the interface and the adjacent perovskite layer, reducing the device efficiency of the perovskite cell.

[0172] In the above-mentioned method for preparing a perovskite cell provided in the present application, a 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 a hole transport layer can eliminate 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, 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, thereby helping to improve the device efficiency of the perovskite cell.

[0173] In some embodiments, preparing the hole transport layer by the first vacuum flash evaporation method may include the following steps:

[0174] S110, coating a solution of a hole transport material on the first electrode layer to form a wet film of the hole transport material;

[0175] 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.

[0176] In the above steps, the wet film of the hole transport material is subjected to a first vacuum flash evaporation treatment, so that 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.

[0177] In some embodiments, the hole transport material includes one or more of 2,2',7,7'-tetrakis[N,N-bis(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-bis(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.

[0178] In some embodiments, the first vacuum flash treatment may be performed in an air atmosphere.

[0179] 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 evaporation treatment is performed, impurities such as water and oxygen in the air will basically have no effect on the hole transport material, and the first vacuum flash evaporation treatment can be carried out directly in an air atmosphere.

[0180] 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.

[0181] 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 ranges.

[0182] The temperature of the first vacuum flash evaporation treatment is within the above range, which is beneficial to reducing the generation of small cracks or wrinkles inside and on the surface of the hole transport layer film, reducing the roughness of the film surface, and improving the flatness of the film surface, thereby improving the device efficiency of the perovskite battery.

[0183] In some embodiments, the extraction rate of the first vacuum flash treatment is 5m 3 / h to 20m 3 / h. For example, the extraction rate of the first vacuum flash process 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 to 20m 3 / h.

[0184] 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 and thus improving the device efficiency of the perovskite battery.

[0185] It is understood that the extraction rate and extraction time of the first vacuum flash evaporation process are related to the power of the first vacuum flash evaporation process and the equipment used to perform the first vacuum flash evaporation process. The power can be adjusted based on the internal capacity of the equipment and actual preparation requirements, and the extraction rate and extraction time can be adjusted accordingly.

[0186] In some embodiments, the extraction time of the first vacuum flash treatment is 10 seconds to 180 seconds. For example, the extraction time can be 10 seconds, 50 seconds, 90 seconds, 130 seconds, 170 seconds, 180 seconds, or any range thereof. Alternatively, the extraction time is 30 seconds to 60 seconds.

[0187] As a non-limiting example, as shown in FIG4 , a wet film of hole transport material can be placed in a sealed container through an opening at one end of the sealed container. A vacuum pump is connected to the other end of the container through an opening, and a first vacuum flash evaporation process can be performed using the container and the vacuum pump. Specifically, the vacuum pump can rapidly extract the air in the container and the solvent in the wet film of hole transport material, thereby forming a thin film of the hole transport layer.

[0188] It is understood that in the perovskite cell of the present application, in addition to 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 cell 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.

[0189] 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.

[0190] By preparing the perovskite layer through 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 thus improve the device efficiency of the perovskite battery.

[0191] In some embodiments, preparing the perovskite layer by the second vacuum flash evaporation method may include the following steps:

[0192] S210, coating a perovskite precursor solution on the hole transport layer to form a perovskite wet film;

[0193] 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 thin film;

[0194] S230 , annealing the perovskite mesophase thin film to form the perovskite layer.

[0195] When preparing perovskite cells, the traditional method is to use an antisolvent method to prepare the perovskite layer. However, in the preparation process of perovskite cells, especially in the preparation of tin-lead perovskite cells, the antisolvent itself is not only highly toxic and pollutes the environment, but also depends heavily on the experimentalist's operating techniques. Uncontrollable human factors, such as the time and speed of droplet addition, can cause uneven perovskite film crystallization quality, poor device reproducibility, and high costs, which are not conducive to commercial production. This has seriously restricted the application of tin-lead perovskite cells.

[0196] Furthermore, the antisolvent method is a rapid crystallization preparation method. Perovskite films are typically formed by rapid nucleation and crystallization from solution at relatively low temperatures. This results in the presence of numerous small grains stacked within the perovskite film, resulting in a complex polycrystalline structure and numerous grain boundaries. These grain boundaries are prone to severe non-radiative recombination, which in turn affects carrier transport, promotes ion migration, and introduces deep-level defects, resulting in a decrease in the device efficiency and stability of the perovskite battery. Furthermore, for tin-lead perovskite batteries, the crystallization rate is much faster than that of conventional pure-lead perovskite batteries. Therefore, tin-lead perovskite films prepared using the antisolvent method will have relatively poorer film quality and a relatively higher defect density, more severe non-radiative recombination, and poorer charge transport, leading to a more significant decrease in the device efficiency and stability of the tin-lead perovskite battery. 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.

[0197] In the embodiment of the present application, the perovskite layer is prepared by vacuum flash evaporation, which can quickly extract the solvent in the perovskite precursor solution, slow down the nucleation and crystallization rate of the perovskite, increase the average size of the grains in the perovskite layer, and promote the growth of grains along the thickness direction of the perovskite layer, improve the consistency and uniformity of grain growth, and reduce the 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 transport efficiency, inhibit ion migration, and reduce 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 slowed down to a greater extent, thereby improving the device efficiency and stability of the tin-lead perovskite battery.

[0198] 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 re-combination 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.

[0199] In addition, the perovskite film prepared by vacuum flash evaporation eliminates the step of manually adding anti-solvent, avoiding the influence of the anti-solvent atmosphere on the perovskite film formation. The device efficiency is higher, the process is simpler, and it is suitable for application in large-scale production.

[0200] In some embodiments, the second vacuum flash treatment may be performed in an environment where the water and oxygen contents are all less than 0.1 parts per million (ppm).

[0201] It should be noted that ppm refers to the mass of water and oxygen as a percentage of the mass of all gases in the environment.

[0202] It should be noted that water and oxygen may react with the perovskite mesophase film and affect the quality of the perovskite film. Therefore, 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, they can be performed in a glove box with a nitrogen atmosphere.

[0203] Optionally, the second vacuum flash evaporation treatment can be performed in a nitrogen atmosphere. This can reduce the impact of water and oxygen on the quality of perovskite film formation, improve the quality of the perovskite film, and further improve the device efficiency of the perovskite battery.

[0204] It can be understood that the perovskite film described in this application is equivalent to the perovskite layer in the perovskite battery.

[0205] 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 any range thereof. Alternatively, the temperature of the second vacuum flash treatment is 18°C ​​to 22°C.

[0206] The temperature of the second vacuum flash evaporation treatment is within the above range, which is beneficial to reducing the generation and stacking of small grains inside the perovskite layer film, reducing the number of grain boundaries, reducing the roughness of the film surface, and improving the flatness of the film surface, thereby improving the device efficiency of the perovskite battery.

[0207] In some embodiments, the extraction rate of the second vacuum flash treatment is 10m 3 / h to 30m 3 / h. For example, the extraction rate of the second vacuum flash process 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 to 30m 3 / h.

[0208] 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.

[0209] It is understood that the extraction rate and extraction time of the second vacuum flash evaporation process are related to the power of the second vacuum flash evaporation process and the equipment used to perform the second vacuum flash evaporation process. The power can be adjusted based on the internal capacity of the equipment and actual preparation requirements, and the extraction rate and extraction time can be adjusted accordingly.

[0210] In some embodiments, the extraction time of the first vacuum flash treatment is 10 seconds to 180 seconds. For example, the extraction time can be 10 seconds, 50 seconds, 90 seconds, 130 seconds, 170 seconds, 180 seconds, or any range thereof. Alternatively, the extraction time is 25 seconds to 40 seconds.

[0211] As a non-limiting example, steps S210 to S230 can be performed in a nitrogen glove box. As shown in FIG4 , in a nitrogen atmosphere, the wet perovskite film can be placed in a sealed container through an opening at one end. A vacuum pump is connected to the other end of the container through an opening, and a second vacuum flash evaporation process can be performed using the container and the vacuum pump. Specifically, the vacuum pump rapidly extracts nitrogen from the container and the solvent from the perovskite precursor solution, thereby forming a perovskite mesophase film. The perovskite mesophase film is then annealed to form a perovskite layer.

[0212] 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 any range thereof. Alternatively, the annealing temperature is 100°C to 130°C.

[0213] 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 a range consisting of any of the above values. Alternatively, the annealing time is 10 min to 20 min.

[0214] The annealing temperature and annealing time are within the above ranges, which is beneficial to further improve the film formation quality of the perovskite thin film, thereby further improving the device efficiency of the perovskite battery.

[0215] 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.

[0216] In some embodiments, the A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of .

[0217] Optionally, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole groups.

[0218] Optionally, the A ions include organic amine ions and Cs + One or more of .

[0219] In some embodiments, the X ions include F - 、Cl - Br - and I - One or more of .

[0220] Optionally, the X ions include Cl - Br - and I - One or more of .

[0221] In some embodiments, the perovskite precursor solution comprises compound APb y Sn 1-y X3,0 <y<1。

[0222] In some embodiments, the method may further include step S30:

[0223] S30, preparing an electron transport layer between the perovskite layer and the second electrode layer.

[0224] 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.

[0225] In a third aspect, the present application provides a stacked battery, which includes the perovskite battery described in the first aspect of the present application or the perovskite battery prepared by the method described in the second aspect of the present application.

[0226] In some embodiments, the laminated battery includes a silicon-calcium laminated battery and a calcium-calcium laminated battery.

[0227] It can be understood that the "silicon-calcium tandem battery" mentioned in this application refers to a battery formed by connecting a silicon solar cell and a perovskite battery in series; the "calcium-calcium tandem battery" refers to a battery formed by connecting a perovskite battery and a perovskite battery in series.

[0228] In a fourth aspect, the present application provides a photovoltaic module 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 stacked cell described in the third aspect of the present application.

[0229] It is understood that the photovoltaic module may include only 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.

[0230] In a fifth 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, the stacked cell described in the third aspect of the present application, and the photovoltaic module described in the fourth aspect of the present application.

[0231] In some embodiments, the perovskite cell can be used as a power generation device for an electrical device. The type of power generation device can include, but is not limited to, an integrated power generation device. The location of the power generation device can include, but is not limited to, the roof or back panel of a vehicle.

[0232] 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.

[0233] Figure 10 shows an example of an electric device, which is a car, and can further be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0234] As another example, the electric device may be a mobile phone, a tablet computer, a laptop computer, a calculator, etc.

[0235] As another example, the power-consuming device may be a wearable device, such as a watch.

[0236] Example

[0237] . Below, some embodiments of the present application are described. The embodiments described below are exemplary and are only used to explain the present application, and should not be understood as limiting the present application. If the technology or conditions are not specified in the examples, they shall be carried out according to the description above, or according to the technology or conditions described in the literature in this field or according to the product instructions. The reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained commercially, or can be synthesized in a conventional manner from commercially available products.

[0238] In the following embodiments, "room temperature" refers to 20°C to 30°C, and further, may be 25°C.

[0239] Example 1

[0240] (1) Preparation of the first electrode

[0241] A 5 cm x 5 cm sheet of FTO conductive glass was laser-etched to leave an insulating area. The sheet was then ultrasonically treated with deionized water, detergent, ethanol, isopropyl alcohol, acetone, ethanol, and deionized water for 20 minutes. The sheet was then dried with nitrogen and cleaned with UV-ozone for 15 minutes. This was then used as the first electrode.

[0242] (2) Preparation of hole transport layer

[0243] ① Prepare a PEDOT:PSS aqueous solution (mass concentration of 1.7 weight percent (wt%)). Take 2 milliliters (mL) of this solution and filter it through a 0.45 micron (μm) pore size filter. Take 200 microliters (μL) of the filtered solution and spin-coat it onto the conductive glass prepared in step (1) using a single-step spin coating method at 4000 revolutions per minute (rpm / min) for 30 seconds.

[0244] ② After the spin coating is completed, 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 approximately 14nm. The vacuum flash evaporation temperature is 25℃, the power is 600 watts (W), the extraction rate is 60 grams / hour (g / h), and the extraction time is 60 seconds.

[0245] (3) Preparation of perovskite layer

[0246] ① Mix methylamine 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).

[0247] ② Place the hole transport layer obtained in step (2) in 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 prepare a perovskite wet film using a single-step spin coating method at a spin coating speed of 4000 rpm / min for 30 s.

[0248] 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.

[0249] ④ The perovskite mesophase film was placed on a hot plate at 100°C for 10 minutes to prepare a perovskite layer (components of FA 0.7 MA 0.3 Pb 0.4 Sn 0.6 I3), the thickness of which is about 900nm.

[0250] (4) Preparation of electron transport layer

[0251] The prepared perovskite layer was placed in a vacuum thermal evaporation device and vacuumed to 4×10 -4 Pa (Pa), deposited 25nm C 60 , 6nm BCP (bathocuproine) is used to obtain the electron transport layer.

[0252] (5) Preparation of the second electrode

[0253] 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, thereby obtaining a perovskite cell.

[0254] Examples 2 to 21

[0255] 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. The specific parameters are detailed in Tables 1 and 2 below. Wherein, “ / ” indicates that the corresponding parameter does not exist.

[0256] Comparative Example 1

[0257] 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.

[0258] Comparative Example 2

[0259] 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; at the same time, an anti-solvent method is used instead of the vacuum flash evaporation method in step (3) to prepare the perovskite mesophase film. The specific preparation process is as follows:

[0260] 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 onto the hole transport layer using a pipette, and a perovskite wet film was prepared using a two-step spin coating method: the first step was a spin coating speed of 2000 rpm / min for 10 s; the second step was a spin coating speed of 5000 rpm / min for 50 s. 400 μL of chlorobenzene was added 20 s before the end of the process to obtain a perovskite mesophase film.

[0261] Table 1

[0262] Table 2

[0263] 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.

[0264] Test Method

[0265] (1) Surface morphology test

[0266] The surface morphologies of the hole transport layer and the perovskite layer were tested using a scanning electron microscope (model: Hitachi, HD-2700) and an atomic force microscope (model: Oxford Instruments, MFP-3D-Origin).

[0267] (2) Photoelectric conversion efficiency test

[0268] At room temperature and pressure, under standard simulated sunlight (AM 1.5G, 100 mW / cm2 2 )) irradiation, the battery performance was tested to 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, Keithley 2440), the short-circuit current density Jsc (unit: milliampere / square centimeter (mA / cm 2 )), open circuit voltage Voc (unit volts (V)), maximum light output current Jmpp (unit milliamperes (mA)) and maximum light output voltage Vmpp (unit V).

[0269] The fill factor FF of the battery can be calculated by the formula FF = Jsc × Voc / (Jmpp × Vmpp), and the photoelectric conversion efficiency PCE of the battery can be calculated by the formula PCE = Jsc × Voc × FF / Pw, where Pw represents the input power in milliwatts (mW).

[0270] “Normal temperature and pressure” refers to normal pressure: the pressure is one atmosphere at a temperature of 25°C; normal temperature refers to 20°C to 30°C, and further, can be 25°C.

[0271] (3) Stability test

[0272] The stability of the perovskite cell was tested under conditions where the device was stored in a nitrogen glove box at a constant temperature of 25°C, away from light. The photocurrent density-voltage curve of the cell device was measured at regular intervals, and the corresponding photoelectric conversion efficiency was normalized to obtain the perovskite cell photovoltaic efficiency decay curve.

[0273] 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.

[0274] Table 3

[0275] In Table 3, by comparing Examples 1 to 21 with the comparative example, it can be seen that the perovskite cell obtained by preparing the hole transport layer or perovskite layer by the vacuum flash evaporation method in the present application has a photoelectric conversion efficiency and stability significantly higher than that of the comparative example, indicating that the vacuum flash evaporation method can improve the photoelectric conversion efficiency and stability of the cell.

[0276] In addition, it can be seen from Figure 5 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.

[0277] As can be seen from Figure 7, the surface of the perovskite layer prepared by the vacuum flash evaporation method 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 the anti-solvent in Example 23 (Figure (a)) is rough and has a large number of pinholes.

[0278] As can be seen from Figures 8 and 9, in the perovskite layer prepared by the vacuum flash evaporation method in Example 1 (Figure 9), the grains grow throughout the thickness direction, and the grains evenly expand to several microns along the base and vertical directions. The interior of the perovskite layer presents a compact and dense morphology; while in the perovskite layer prepared by the anti-solvent method in Example 18 (Figure 8), small grains are stacked on each other (with a size between 200nm and 400nm), and there are a large number of grain boundaries. Severe non-radiative recombination is prone to occur at these grain boundaries, resulting in a decrease in the photoelectric conversion efficiency and stability of the perovskite battery.

[0279] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0280] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and within the scope of the technical solution of the present application, embodiments that have substantially the same structure as the technical idea and exert 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 their descriptions are relatively detailed, but they cannot be understood as limiting the scope of the patent. In addition, without departing from the scope of the subject matter of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of constructing by combining 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 modifications and improvements can be made, which all fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be based on the attached claims, and the description and drawings may be used to explain the content of the claims.

Claims

1. A perovskite battery, comprising 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, and Ra1<3nm.

2. The perovskite cell according to claim 1, wherein: The surface roughness Ra1 of the hole transport layer satisfies: <Ra1≤1.5nm。 3. The perovskite cell according to claim 1 or 2, wherein: The number of pinholes per unit area of ​​the hole transport layer is n1, 0≤n1≤2.

4. The perovskite cell according to any one of claims 1 to 3, wherein: The number of pinholes per unit area of ​​the hole transport layer is n1, 0≤n1≤1.

5. The perovskite cell according to any one of claims 1 to 4, wherein: The perovskite layer includes crystal grains distributed throughout the thickness direction of the perovskite layer.

6. The perovskite cell according to claim 5, wherein: The average size of the crystal grains is 600 nm to 800 nm.

7. The perovskite cell according to claim 5 or 6, wherein: The average size of the crystal grains is 650 nm to 750 nm.

8. The perovskite cell according to any one of claims 1 to 7, wherein: The surface roughness of the perovskite layer is Ra2, Ra2<3nm.

9. The perovskite cell according to any one of claims 1 to 8, wherein: The number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤2.

10. The perovskite cell according to any one of claims 1 to 9, wherein: The number of pinholes per unit area of ​​the perovskite layer is n2, 0≤n2≤1.

11. The perovskite cell according to any one of claims 1 to 10, wherein: One or more of the following conditions are met: (1) The thickness of the hole transport layer is 10 nm to 30 nm; (2) The thickness of the perovskite layer is 700 nm to 1200 nm.

12. The perovskite cell according to any one of claims 1 to 11, wherein: One or more of the following conditions are met: (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; (2) The perovskite cell further includes an electron transport layer, which is disposed between the perovskite layer and the second electrode layer.

13. The perovskite cell according to claim 12, wherein: One or more of the following conditions are met: (1) The A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of; Wherein, the organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole; (2) 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; (3) The C ions include Cs + 、Ag + , K + And Ru + One or more of; (4) The D ions include Bi 3+ 、Ni 3+ , Fe 3+ and Cu 3+ One or more of; (5) The X ions include F - , Cl - Br - and I - One or more of .

14. The perovskite cell according to claim 12 or 13, wherein: One or more of the following conditions are met: (1) The A ions include organic amine ions and Cs + One or more of; (2) The B ions include Pb 2+ and Sn 2+ One or both of the following: (3) The X ions include Cl - Br - and I - One or more of; (4) The perovskite layer contains compound APb y Sn 1-y X3,0 <y<1。 15. A method for preparing a perovskite battery, comprising: 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.

16. The method according to claim 15, wherein: 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; The first vacuum flash evaporation treatment is performed 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.

17. The method according to claim 16, wherein: One or more of the following conditions are met: (1) The first vacuum flash evaporation treatment is carried out in an air atmosphere; (2) the temperature of the first vacuum flash treatment is 15° C. to 35° C.; (3) The extraction rate of the first vacuum flash treatment is 5m 3 / h to 20m 3 / h; (4) 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.

18. The method according to any one of claims 15 to 17, wherein: 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; The perovskite intermediate phase film is annealed to form the perovskite layer.

19. The method according to claim 18, wherein: One or more of the following conditions are met: (1) The second vacuum flash treatment is carried out in a nitrogen atmosphere; (2) the temperature of the second vacuum flash treatment is 15° C. to 35° C.; (3) The extraction rate of the second vacuum flash treatment is 10m 3 / h to 30m 3 / h; (4) The annealing temperature is 70°C to 130°C; (5) The annealing time of the annealing treatment is 5 minutes to 30 minutes; (6) 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; The A ions include organic cations, Li + 、Na + , K + , Rb + and Cs + One or more of; The organic cation includes at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, carbamimidyl and imidazole; 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; The C ions include Cs + 、Ag + , K + And Ru + One or more of; The D ions include Bi 3+ 、Ni 3+ , Fe 3+ and Cu 3+ One or more of; The X ions include F - , Cl - Br - and I - One or more of .

20. The method according to claim 19, wherein: The perovskite precursor solution contains compound APb y Sn 1-y X3,0 <y<1。 21. The method according to any one of claims 15 to 20, wherein: Also includes: An electron transport layer is prepared between the perovskite layer and the second electrode layer.

22. A stacked cell, comprising the perovskite cell according to any one of claims 1 to 14 or a perovskite cell prepared by the method according to any one of claims 15 to 21.

23. A photovoltaic module, comprising at least one of the perovskite cell according to any one of claims 1 to 14, the perovskite cell prepared by the method according to any one of claims 15 to 21, and the stacked cell according to claim 22.

24. An electrical device comprising at least one of the perovskite cell according to any one of claims 1 to 14, the perovskite cell produced by the method according to any one of claims 15 to 21, the stacked cell according to claim 22, and the photovoltaic module according to claim 23.

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