Perovskite solar cell, its manufacturing method and power consumption device

Abstract

The present application relates to a perovskite solar cell, its manufacturing method and power consumption device. The perovskite solar cell includes a bottom electrode, a perovskite layer and a top electrode, the perovskite layer includes a plurality of sub-perovskite films arranged in a stacked manner, and the band gaps of the adjacent two sub-perovskite films are different. The perovskite solar cell can increase the spectral absorption conversion range, and the thickness and band gap are controllable, there is no defect layer, and the band gap of the absorption conversion layer can be adjusted, which effectively increases the spectral absorption conversion range and improves the external output of the perovskite solar cell.

Description

[Technical field]

[0001] The present application relates to the technical field of solar cells, and in particular to perovskite solar cells and their manufacturing methods and power consuming devices. [Background technology]

[0002] Perovskite solar cells are solar cells that use perovskite-type organometal halide semiconductors as light-absorbing materials. They belong to the third generation of solar cells and are also called new concept solar cells.

[0003] The key component of perovskite solar cells is the perovskite layer as the absorption conversion layer. The band gap of conventional perovskite layers is a constant value according to the material composition, which is about 1.6 eV, so that the main absorption range of the solar spectrum is in the visible light wavelength range, and the spectral energy of the visible light and near infrared wavelength range cannot be absorbed and converted to the maximum extent, thus limiting the improvement of the device efficiency. Summary of the Invention [Problem to be solved by the invention]

[0004] The laminated cell is a stacked series structure formed by adding a central tunnel layer to two independent cells using two independent different band gap absorption layers, and may be called a two-terminal laminated cell. The four-terminal laminated cell is a series-parallel output structure formed by mechanically bonding two completely independent cell assemblies. The laminated cell and the four-terminal laminated cell have to some extent solved the problem of the single band gap of the individual perovskite layer, but since the band gap of each cell is unique, in the process of connecting two cells using independent different band gap structures, it is necessary to consider problems such as current matching, tunnel junction fabrication, and extra light absorption loss due to the substrate material, and even in terms of process steps and cost control, it brings about a great restriction to the application of perovskite solar cells. [Means for solving the problem]

[0005] To achieve the above object, a first aspect of the present application provides a perovskite solar cell, the cell comprising a bottom electrode, a perovskite layer, and a top electrode, the perovskite layer comprising multiple sub-perovskite films arranged in a stacked manner, and the band gaps of two adjacent sub-perovskite films are different.

[0006] The above-mentioned perovskite solar cell can increase the spectral absorption conversion range, and the sub-perovskite films are independent of each other, the thickness and band gap are controllable, there is no defect layer, and the band gap of the absorption conversion layer can be adjusted, which effectively increases the spectral absorption conversion range and improves the external output of the perovskite solar cell.

[0007] In one embodiment thereof, the band gaps of the sub-perovskite layers are graded in ascending order, and optionally, the bottom electrode is a transparent electrode, and along the direction from the bottom electrode to the top electrode, the band gaps of the sub-perovskite layers are graded in ascending order, thus matching the spectral absorption characteristics of solar cells and increasing the spectral absorption conversion range.

[0008] In one embodiment thereof, the number of layers of the sub-perovskite film is 2 to 10 layers, optionally, the number of layers of the sub-perovskite film is 2 to 5 layers, and further optionally, the number of layers of the sub-perovskite film is 2 to 3 layers.

[0009] In one embodiment, the band gap difference between the two adjacent sub-perovskite films is 0.01 eV to 0.5 eV, optionally, the band gap difference between the two adjacent sub-perovskite films is 0.05 eV to 0.2 eV, and further optionally, the band gap difference between the two adjacent sub-perovskite films is 0.08 eV to 0.12 eV. By designing the sub-perovskite films according to the gradient of the difference, it is possible to realize the best absorption corresponding to different spectral wavelength ranges, maximize the utilization of the light wave energy of different wavelengths of the spectrum, and improve the photoelectric absorption conversion efficiency.

[0010] In one embodiment, the multi-layer sub-perovskite film includes at least one wide band gap layer and one narrow band gap layer, and the band gap G of the wide band gap layer is w is 1.2 eV to 2.0 eV, and the band gap G of the narrow band gap layer n is 0.8 eV to 1.8 eV, and G n ≦G w It is.

[0011] In one embodiment thereof, the sub-perovskite film is a vapor-deposited film.

[0012] In one embodiment thereof, the sub-perovskite film has a thickness of 200 nm to 2 μm, optionally, the sub-perovskite film has a thickness of 300 nm to 1 μm, and further optionally, the sub-perovskite film has a thickness of 300 nm to 600 nm.

[0013] In one embodiment, the material of the sub-perovskite film is selected from one or more compounds represented by the following general structural formula (I): ABX3(I) where A represents one or a mixture of cations, optionally A includes one or more of the following: methylamine cation, formamidine cation, and caesium ion; B represents a cation or mixture of cations, optionally B comprises a metal cation or mixture of metal cations, further optionally B is Pb 2+ , Sn 2+ and Ge 2+ One or more of the following: X represents a halogen anion or a mixture of halogen anions, optionally X is Cl - , Br - and I - Includes one or more of the following.

[0014] In one embodiment thereof, the perovskite solar cell is a film-type cell.

[0015] A second aspect of the present application provides a method for producing a perovskite solar cell, the method comprising: Producing a perovskite layer on a surface of a bottom electrode, the perovskite layer comprising a plurality of sub-perovskite films disposed in a stacked manner, the band gaps of two adjacent sub-perovskite films being different; and fabricating a top electrode on the surface of the perovskite layer.

[0016] In one embodiment, the sub-perovskite film is manufactured by a deposition method, which can ensure the independence of the sub-perovskite films from each other.

[0017] In one embodiment, when the deposition method is used to prepare the sub-perovskite film, (1) The evaporation temperature is 100℃ to 300℃. (2) the deposition distance is 10 cm to 50 cm, and optionally, the deposition distance is 10 cm to 30 cm; (3) Vacuum level is (0.5~3)×10 -6 mbar; (4) During the deposition process, the substrate adopts a rotation mode, and the substrate temperature is 15℃~30℃; (5) After completing the deposition of the multi-layer sub-perovskite film, the method further includes an annealing step, and optionally, the annealing conditions satisfy at least one of the following characteristics: the temperature is 110°C to 140°C, and the time is 3 to 20 minutes.

[0018] A third aspect of the present application provides a power consuming device, the power consuming device comprising a perovskite solar cell selected from the perovskite solar cell according to the first aspect, or a perovskite solar cell produced by the production method according to the second aspect. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a schematic diagram of bandgap matching and thicknesses of wide and narrow bandgap layers in one example. [Diagram 2] FIG. 1 is a schematic diagram of the absorption spectrum of a perovskite solar cell in one example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, with appropriate reference to the drawings, embodiments specifically disclosing the perovskite solar cell, the manufacturing method thereof, and the power consumption device of the present application will be described in detail. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters and duplicated description of structures that are actually the same may be omitted. This is to avoid the following description becoming unnecessarily long and to allow those skilled in the art to easily understand. Note that the drawings and the following description are provided to allow those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.

[0021] The "ranges" disclosed in this application are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, and the selected lower and upper limits define the boundaries of the particular range. Such defined ranges may be inclusive or exclusive of the end values, and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also envisaged. It is noted that if 1 and 2 are listed as the minimum range values, and 3, 4, and 5 are listed as the maximum range values, then the ranges 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5 are all envisaged. In this application, unless otherwise specified, a numerical range "a-b" represents a shorthand representation of any combination of real numbers a-b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed herein, and "0-5" is just a shorthand for combinations of these numbers. Also, expressing a parameter as an integer ≧2 is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Unless otherwise stated, all the embodiments and optional embodiments in the present application can be combined with each other to form a new technical solution.

[0023] Unless otherwise stated, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0024] Unless otherwise stated, all steps in this application may be performed in sequence or randomly, and preferably in sequence. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method mentioned above may further include step (c), which means that step (c) may be added to the method in any order, such as the method may include steps (a), (b) and (c), may include steps (a), (c) and (b), may include steps (c), (a) and (b), etc.

[0025] Unless otherwise specified, the terms "comprise" and "include" referred to in this application may be open ended or closed ended. For example, the terms "comprise" and "include" may further include or include other ingredients not listed, or may include or include only the ingredients listed.

[0026] Unless otherwise stated, in this application, the term "or" is inclusive. For example, the term "A or B" means "A, B, or both A and B." More specifically, "A or B" is satisfied by the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) but B is true (or exists); and A and B are both true (or exist).

[0027] At present, perovskite solar cells have only one band gap of the absorption conversion layer, and the absorption spectrum range is limited, which limits the efficiency improvement and makes it impossible to realize the structural design of high efficiency, low cost and large current matching window. For laminated cells and four-terminal laminated cells, problems such as current matching, tunnel junction fabrication, and extra light absorption loss caused by the substrate material need to be considered, and the process steps are complicated and the cost is high. Therefore, it is necessary to provide a perovskite solar cell that can increase the spectral absorption conversion range and adjust the band gap of the absorption conversion layer, providing a wider window for the industrialization and technical improvement of perovskite solar cells.

[0028] At the same time, in the conventional method for producing perovskite layers, the solvent method is common, that is, the material of the perovskite layer is prepared in a solution, and then coated to form a perovskite layer. However, this method is difficult to obtain a multi-layered, mutually independent sub-perovskite film with different band gaps, because when the surface of the first perovskite layer is coated with a solution again, the solution partially dissolves the surface material of the first perovskite layer, so that the band gap interface and the thickness of the perovskite layer cannot be effectively controlled, the interface becomes unclear, and a new defect layer is formed at the interface. A method is to contact two perovskite layers with different band gaps with each other, and to form a gradient band gap by ion permeation through the selection of materials, but the ion exchange process is uncontrollable, making it difficult to obtain a multi-layered, mutually independent sub-perovskite film with different band gaps, and the ion exchange eventually reaches equilibrium, and the gradient band gap formed is only a temporary state, and it is highly likely that a single band gap perovskite layer will be formed in the end. As can be seen, the conventional methods cannot obtain multi-layered, independent sub-perovskite films with different band gaps, and the conventional methods have problems such as high process realization cost, small window, and complicated post-processing.

[0029] On this basis, the present application provides a perovskite solar cell, the cell comprising a bottom electrode, a perovskite layer and a top electrode, the perovskite layer comprising multiple layers of sub-perovskite films arranged in a stacked manner, and the band gaps of two adjacent sub-perovskite films are different.

[0030] As will be understood, "multiple layers" means two or more layers, including, but not limited to, two, three, four or more layers.

[0031] As can be understood, the "film" in the sub-perovskite film refers to a layer structure that can exist independently, the size of the band gap is determined, and there are clear interfaces between each layer, and there is no macroscopic situation of interpenetration or doping.

[0032] In the perovskite layer of the perovskite solar cell, the sub-perovskite films have different bandgaps (for example, the bandgap size can be adjusted by element type and composition), which can increase the spectral absorption conversion range, and the sub-perovskite films are independent of each other, the thickness and bandgap can be controlled, there is no defect layer, and the bandgap of the absorption conversion layer can be adjusted, which effectively increases the spectral absorption conversion range and improves the external output of the perovskite solar cell. At the same time, the perovskite solar cell also has the following advantages:

[0033] (1) Compared with laminated cells and four-terminal laminated cells, there is no need to consider issues such as current matching, tunnel junction manufacturing, and excess light absorption loss due to substrate materials, which improves the performance of perovskite solar cells while reducing the difficulty of structural design. The process steps are simple, the window is wide, the manufacturing costs are low, and it is easy to produce and apply on a large scale.

[0034] (2) Multiple sub-perovskite layers have different bandgaps, which can effectively convert more spectral energy and provide more room for improving device current density.

[0035] (3) It can match the best absorption of different wavelength ranges of the spectrum to achieve the goal of maximal light absorption and conversion.

[0036] (4) After completing the fabrication of the perovskite layer, if necessary, an in-line process can still be adopted to realize the interface transition treatment and further widen the process window.

[0037] In some of these examples, the band gaps of the sub-perovskite layers are sequentially increased, and the bottom electrode is a transparent electrode, and the band gaps of the sub-perovskite layers are sequentially increased along the direction from the bottom electrode to the top electrode, thus matching the spectral absorption characteristics of solar cells and increasing the spectral absorption conversion range.

[0038] In some of these examples, the number of layers in the sub-perovskite film is 2 to 10. Further, the number of layers in the sub-perovskite film is 2 to 5. Further, the number of layers in the sub-perovskite film is 2 to 3.

[0039] In some examples, the band gap difference between the two adjacent sub-perovskite films is 0.01 eV to 0.5 eV. Specifically, the band gap difference between the two adjacent sub-perovskite films includes, but is not limited to, 0.01 eV, 0.05 eV, 0.08 eV, 0.09 eV, 0.1 eV, 0.11 eV, 0.12 eV, 0.15 eV, 0.2 eV, 0.3 eV, 0.4 eV, and 0.5 eV. By designing the sub-perovskite film according to the gradient of the difference, it is possible to realize the best absorption corresponding to different spectral wavelength ranges, maximize the use of light wave energy of different wavelengths of the spectrum, and improve the photoelectric absorption conversion efficiency. At the same time, the existence of a certain difference in the band gap between the two sub-perovskite films can reduce the difference in energy level between the layers, and promote the extraction and transport of photoinduced carriers.

[0040] In some of these examples, the difference in band gap between the adjacent two sub-perovskite film layers is 0.05 eV to 0.2 eV, and further, the difference in band gap between the adjacent two sub-perovskite film layers is 0.08 eV to 0.12 eV.

[0041] In some of these examples, the multi-layer sub-perovskite film includes at least one wide band gap layer and one narrow band gap layer, and the band gap G of the wide band gap layer is w is 1.2 eV to 2.0 eV, and the band gap G of the narrow band gap layer n is 0.8 eV to 1.8 eV, and G n ≦G w Illustratively, the band gap matching and thickness of the wide band gap layer and the narrow band gap layer are as shown in FIG. 1, and the schematic diagram of the absorption spectrum is as shown in FIG.

[0042] In some of these examples, the sub-perovskite film is a vapor-deposited film.

[0043] In some of these examples, among any two adjacent sub-perovskite films, the thickness of the sub-perovskite film having a wider band gap is H1, the thickness of the sub-perovskite film having a narrower band gap is H2, and H1 <H2である。

[0044] In some of these examples, the thickness of the sub-perovskite film is 200 nm to 2 μm. Specifically, the thickness of the sub-perovskite film includes, but is not limited to, 200 nm, 300 nm, 350 nm, 380 nm, 400 nm, 420 nm, 450 nm, 500 nm, 530 nm, 550 nm, 570 nm, 600 nm, 650 nm, 700 nm, 800 nm, 900 nm, 1 μm, 1.5 μm, and 2 μm.

[0045] In some of these examples, the thickness of the sub-perovskite film is 300 nm to 1 μm.Furthermore, the thickness of the sub-perovskite film is 300 nm to 600 nm.

[0046] In some of these examples, the material of the sub-perovskite film is selected from one or more compounds represented by the following general structural formula (I): ABX3(I) where A represents one or a mixture of cations. As can be appreciated, the cations may refer to organic, inorganic, or a mixture of organic and inorganic cations in various ratios.

[0047] In some of these examples, A is a methylamine cation (MA + ), formamidine cation (FA + ) and cesium ion (Cs + By employing an appropriate A, the octahedral structure of lead iodide can be better stabilized, thereby improving the stability of the device.

[0048] where B represents one or a mixture of cations. As can be appreciated, the cations may refer to organic, inorganic, or a mixture of organic and inorganic cations in various ratios.

[0049] In some of these examples, B includes one or more mixed metal cations. Further, B includes Pb 2+ , Sn 2+ and Ge 2+ By using an appropriate B, the band gap of the device can be controlled and the device performance can be improved.

[0050] Here, X represents one or more halogen anions. Non-limiting examples of X include Cl. - , Br - and I - Includes one or more of the following.

[0051] In some of these examples, the perovskite solar cell is a film-type cell.

[0052] In some of the examples, the bottom electrode is used for light incidence, specifically, a transparent conductive base, which may be, but is not limited to, a glass base or a flexible base, specifically, the flexible base may be one or more of organic polymer materials, such as polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS).

[0053] Without limitation, the material of the top electrode may be a conductive material that is organic, inorganic, or a mixture of both in various ratios, in some examples of which the material of the top electrode may be a metallic conductive material, such as gold (Au), silver (Ag), copper (Cu), or a mixture thereof, or a conductive oxide, such as FTO, ITO, etc.

[0054] In some embodiments, the perovskite solar cell further includes one or both of an electron transport layer and a hole transport layer. Specifically, the perovskite solar cell includes a forward structure type and an inverted structure type. As the forward structure type, the perovskite solar cell includes a bottom electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a top electrode, which are sequentially stacked on the bottom electrode. As the inverted structure type, the perovskite solar cell includes a bottom electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a top electrode, which are sequentially stacked on the bottom electrode.

[0055] Non-limiting examples of materials for the electron transport layer include imide compounds, quinone compounds, fullerene and its derivatives, methoxytriphenylamine-fluoroformamidine (OMeTPA-FA), calcium titanate (CaTiO3), lithium fluoride (LiF), calcium fluoride (CaF2), poly(3,4-ethylenedioxythiophene), polystyrenesulfonic acid (PEDOT:PSS), poly3-hexylthiophene (P3HT), triptycene-based triphenylamine (H101), 3,4-ethylenedioxythiophene-methanidine (H102), and the like. The materials include one or more of the following materials and their derivatives: diethyltriphenylamine (EDOT-OMeTPA), N-(4-aniline)carbazole-spirobifluorene (CzPAF-SBF), polythiophene, metal oxides (wherein the metal element is selected from Mg, Ni, Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, or Cr), silicon oxide (SiO2), strontium titanate (SrTiO3), cuprous thiocyanate (CuSCN), and mixtures thereof.

[0056] Non-limiting examples of materials for the hole transport layer include 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), polytriarylamine (PTAA), NiOx, poly(3,4-ethylenedioxythiophene), polystyrene sulfonate (PEDOT:PSS), WO3, and their derivatives, or a mixture of two or more of these materials.

[0057] The present application further provides a method for producing a perovskite solar cell, the method comprising: Producing a perovskite layer on a surface of a bottom electrode, the perovskite layer comprising a plurality of sub-perovskite films disposed in a stacked manner, the band gaps of two adjacent sub-perovskite films being different; and forming a top electrode on the surface of the perovskite layer.

[0058] In some of the examples, the sub-perovskite film is manufactured by deposition. The deposition method used to manufacture the sub-perovskite film can ensure the independence of the sub-perovskite films, control the band gap width and thickness of the sub-perovskite film of the previous layer, and increase the interface processing window of the sub-perovskite film of the subsequent layer, so that the band gap width and thickness of the sub-perovskite film of the subsequent layer can be controlled as well, reducing the damage to the sub-perovskite film of the previous layer, reducing the inter-permeation, doping and formation of defect layer between the sub-perovskite films, avoiding the inconsistency of device performance, and further ensuring the controllability of the thickness and band gap of each sub-perovskite film, and increasing the spectral absorption conversion range.

[0059] Without being limited thereto, the preparation by the deposition method may adopt an online method or an in-situ method to carry out the co-deposition of materials, and the co-deposition materials may be AX and BX2, respectively.

[0060] In some of these examples, the evaporation temperature of the vapor deposition method is 100° C. to 300° C. The evaporation temperature can be controlled by controlling the current source of the vapor deposition device to control the current.

[0061] In some of the examples, the deposition distance of the deposition method is 10 cm to 50 cm. Specifically, the deposition distance of the deposition method includes, but is not limited to, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 40 cm, and 50 cm. Furthermore, the deposition distance is 10 cm to 30 cm.

[0062] In some of these examples, the degree of vacuum in the deposition method is (0.5 to 3) × 10 -6 mbar. Specifically, the vacuum degree of the deposition method is 0.5×10 -6 mbar, 0.8×10 -6 mbar, 1×10 -6 mbar, 1.2×10 -6 mbar, 1.5×10 -6 mbar, 2×10 -6 mbar, 3×10 -6 Including, but not limited to, mbar.

[0063] In some examples, during the deposition process of the deposition method, the substrate adopts a rotation mode, and the substrate temperature is 15° C. to 30° C. Specifically, the substrate temperature includes, but is not limited to, 15° C., 17° C., 18° C., 19° C., 20° C., 21° C., 22° C., 23° C., 25° C., 27° C., and 30° C.

[0064] In some examples, the method further includes an annealing step after completing the deposition of multiple layers of sub-perovskite films. After completing the deposition of each sub-perovskite film, the annealing can be performed in bulk to crystallize the film, eliminating a step and simultaneously achieving the manufacture of different band gap structures of the absorption conversion layer. Non-limitingly, the deposition of a single layer of sub-perovskite film can be directly annealed to crystallize the film, and the deposition and annealing can be performed for each sub-perovskite film.

[0065] In some of the examples, the annealing temperature is 110° C. to 140° C. Specifically, the annealing temperature includes, but is not limited to, 110° C., 120° C., 130° C., 135° C., and 140° C.

[0066] In some examples, the annealing time is 3 to 20 minutes, including, but not limited to, 3 minutes, 5 minutes, 8 minutes, 10 minutes, 13 minutes, 15 minutes, 17 minutes, and 20 minutes.

[0067] In some of these examples, the annealing conditions include a temperature of 110° C. to 140° C. and a time of 3 to 20 minutes.

[0068] The perovskite solar cell and advantages of the above manufacturing method are similar to those of the perovskite solar cell of the present application described above, and therefore a detailed description thereof will be omitted here.

[0069] The present application further provides an electrical power consuming device, comprising a perovskite solar cell as described above, or a perovskite solar cell manufactured by the manufacturing method as described above. Working Example

[0070] In order to clarify the technical problems, technical solutions and beneficial effects that the present application aims to solve, the present application will be described in more detail below in conjunction with the embodiments and drawings. It is apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. The following description of at least one exemplary embodiment is for illustrative purposes only, and is not a limitation on the present application and its applications. All other embodiments obtained based on the embodiments of the present application without the need for creative efforts by those skilled in the art are within the scope of protection of the present application.

[0071] If specific techniques or conditions are not specified in the examples, they will be performed according to techniques or conditions described in the literature in the art or in the product instructions. Reagents or instruments used that are not specified by manufacturer are all common products that can be purchased commercially. Manufacturing Example 1

[0072] 1) For a set of FTO conductive glass with specifications of 30cm*30cm, 0.5m*1m, 1m*2m, use laser to etch P1, the width of P1 is about 30μm, cut and insulate the FTO conductive layer of the entire glass, and then divide it into several sub-battery electrodes;

[0073] 2) After etching, the conductive glass surface was washed twice with acetone and isopropanol, immersed in deionized water and ultrasonicated for 10 min, and then dried in a blower dryer before being placed in a drying room (humidity less than 2%), which was used as the first electrode (bottom electrode).

[0074] 3) The cleaned conductive glass is placed in a magnetron sputter to deposit a single layer of NiO hole transport layer with a thickness of about 15 nm.

[0075] 4) After the hole transport layer is manufactured, the perovskite light absorbing layer is manufactured. The manufacturing method adopts multi-source deposition method, in which lead iodide is used as the lead source and iodine source, and MAI / FAI is used as the methylamine / formamidine and iodine source.

[0076] 4.1 Preparation of a film layer with a wide band gap of about 1.62 eV: The perovskite component used is MAPbI3, and the method is a binary deposition method, in which lead iodide is the lead source and iodine source, MAI is the methylamine and iodine source, 500 mg MAI and 300 mg PbI2 are the two sources, and evaporated at 120 °C and 295 °C, respectively, to control the deposition thickness to about 330 nm. During the deposition process, the substrate adopts a rotation mode and is cooled to about 21 ° by water cooling, the deposition distance is about 20 cm, and the vacuum degree is 1 × 10 -6 The pressure was controlled at mbar.

[0077] 4.2 Preparation of a thin film layer with a narrow band gap of about 1.51 eV: The perovskite component used is FAPbI3, and the method is a binary deposition method, in which lead iodide is the lead source and iodine source, and 1000 mg FAI is the formamidine and iodine source. The MAI source is turned off, the FAI source is turned on, the deposition temperature is controlled at 165°C, the PbI2 source is maintained, and the deposition film thickness is controlled at about 500 nm. During the deposition process, the substrate adopts a rotation mode and is cooled to about 21° by water cooling, the deposition distance is about 20 cm, and the vacuum degree is 1×10 -6 The pressure was controlled at mbar.

[0078] 4.3 After completing the preparation of both the dual band gap perovskite dry films, the substrate is put into the crystallization furnace and annealed under the condition of 140 ° C for 15 minutes, and then cooled and taken out for the next step;

[0079] 5) The base on which the perovskite absorber layer was fabricated was placed in a vacuum thermal evaporation apparatus and 4 × 10 -4 Pump the vacuum to 30 Pa and deposit 30 nm of C60-N and 8 nm of BCP as the electron transport layer of the assembly.

[0080] 6) After completing the deposition of the electron transport layer in the vacuum thermal evaporation equipment, subsequently deposit 10 nm of Cu on its surface, and then break the vacuum and take out, laser etch P2, the width of P2 is 150 μm, the depth is etched to the FTO layer, the distance between P2 and P1 is 20 μm, and the base is put into the evaporation equipment again to be etched 4×10 -4 After evacuation to 100 Pa, a single layer of Cu was subsequently deposited to a thickness of about 80 nm.

[0081] 7) After cooling, the vacuum is broken and the wafer is taken out. Laser etching is performed on P3. The width of P3 is 15 μm, and the wafer is etched to the FTO layer. The distance between P3 and P2 is 20 μm (the etching lines are P1 / P2 / P3 in order).

[0082] 8) The assembly was then infrared trimmed and etched 10 mm on each side of the assembly to obtain a perovskite solar cell assembly.

[0083] 9) AAA class steady state solar simulator, 1000W / m 2 The assembly parameters were tested under conditions of 25°C.

[0084] The perovskite solar cell assemblies of Manufacturing Examples 2 to 5 and Comparative Example 1 are similar to the manufacturing method of Example 1, with the difference being that the thicknesses of the wide band gap film layer and the narrow band gap film layer are changed, and further the band gaps are changed.

[0085] The assembly of the perovskite solar cell in the comparative manufacturing method 2 is similar to that in the embodiment 1, except that the perovskite light absorbing layer in step 4) is manufactured by a solvent method, and the steps are as follows:

[0086] 4.1 Preparation of a film layer with a wide band gap of about 1.62 eV: The perovskite component used was MAPbI3, and the perovskite precursor solution contained N,N-dimethylformamide and dimethylsulfoxide in a solvent volume ratio of 4:1 as a solvent, 1.2 mol / L lead iodide, and 1.2 mol / L methylamine hydroiodide as a solvent. The spin-coating conditions were 3000 rpm, 30 s, and a poor solvent was added dropwise from the remaining 5 s, and annealed at 100 °C for 30 min.

[0087] 4.2 Preparation of a film layer with a narrow band gap of about 1.51 eV: The perovskite component used was FAPbI3, and the perovskite precursor solution contained N,N-dimethylformamide and dimethylsulfoxide in a solvent volume ratio of 4:1 as a solvent, 1.2 mol / L lead iodide, and 1.2 mol / L formamidine hydroiodide as a solvent. The spin-coating conditions were 5000 rpm, 30 s, and the poor solvent was added dropwise from the remaining 5 s, and annealed at 140 °C for 10 min.

[0088] The parameters and test results of the perovskite solar cell assemblies of Manufacturing Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 1.

[0089] [Table 1]

[0090] As can be seen from Table 1, all of Examples 1 to 5 can achieve better device performance than Comparative Examples 1 to 2, especially Comparative Example 2 has an unclear interface between its wide band gap layer and narrow band gap layer, which causes defects and further deteriorates the device performance. In Examples 1 to 5, when the thickness of the wide band gap perovskite is 400 nm and the thickness of the narrow band gap perovskite is 550 nm, the device performance is the best.

[0091] It should be noted that the present application is not limited to the above-mentioned embodiment. The above-mentioned embodiment is an example, and any embodiment having substantially the same configuration as the technical idea and achieving the same effect within the scope of the technical proposal of the present application is included in the technical scope of the present application. In addition, various modifications that a person skilled in the art can make to the embodiment and other forms constructed by combining some of the components in the embodiment are also included in the scope of the present application, within the scope of the purpose of the present application.

Claims

1. 1. A perovskite solar cell comprising: a bottom electrode; a perovskite layer; and a top electrode, wherein the perovskite layer comprises a plurality of sub-perovskite films arranged in a stacked manner, and the band gaps of two adjacent sub-perovskite films are different.

2. 2. The perovskite solar cell of claim 1, wherein the bandgaps of the multiple layers of sub-perovskite films vary in order of increasing bandgap, and optionally the bottom electrode is a transparent electrode, and along a direction from the bottom electrode to the top electrode, the bandgaps of the multiple layers of sub-perovskite films vary in order of increasing bandgap.

3. The perovskite solar cell according to any one of claims 1 to 2, characterized in that the number of layers of the sub-perovskite film is 2 to 10 layers, optionally the number of layers of the sub-perovskite film is 2 to 5 layers, and further optionally the number of layers of the sub-perovskite film is 2 to 3 layers.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that the band gap difference between the two adjacent sub-perovskite films is 0.01 eV to 0.5 eV, optionally, the band gap difference between the two adjacent sub-perovskite films is 0.05 eV to 0.2 eV, and further optionally, the band gap difference between the two adjacent sub-perovskite films is 0.08 eV to 0.12 eV.

5. The multi-layer sub-perovskite film includes at least one wide band gap layer and one narrow band gap layer, and the band gap G of the wide band gap layer ｗ is 1.2 eV to 2.0 eV, and the band gap G of the narrow band gap layer ｎ is between 0.8 eV and 1.8 eV, and G ｎ ≦G ｗ The perovskite solar cell according to any one of claims 1 to 4, characterized in that

6. The perovskite solar cell according to any one of claims 1 to 5, characterized in that the sub-perovskite film is a vapor-deposited film.

7. The perovskite solar cell according to any one of claims 1 to 6, wherein the sub-perovskite film has a thickness of 200 nm to 2 μm, optionally, the sub-perovskite film has a thickness of 300 nm to 1 μm, and further optionally, the sub-perovskite film has a thickness of 300 nm to 600 nm.

8. The material of the sub-perovskite film is selected from one or more compounds represented by the following general structural formula (I): A.B.X. ３ (I) wherein A represents one or a mixture of cations, optionally A includes one or more of the following: methylamine cation, formamidine cation, and cesium ion; B represents a cation or mixture of cations, optionally B comprises a metal cation or mixture of metal cations, further optionally B is Pb ２＋ , Sn ２＋ and Ge ２＋ One or more of the following: X represents a halogen anion or a mixture of halogen anions, optionally X is Cl － , B － and I － The perovskite solar cell according to any one of claims 1 to 7, characterized in that it contains one or more of the following:

9. The perovskite solar cell according to any one of claims 1 to 8, characterized in that the perovskite solar cell is a film-type cell.

10. A method for producing a perovskite solar cell, comprising the steps of: Producing a perovskite layer on a surface of a bottom electrode, the perovskite layer comprising a plurality of sub-perovskite films disposed in a stacked manner, the band gaps of two adjacent sub-perovskite films being different; fabricating a top electrode on a surface of the perovskite layer; A method for producing a perovskite solar cell, comprising:

11. The method for producing a perovskite solar cell according to claim 10, wherein the sub-perovskite film is produced by a deposition method.

12. When the deposition method is used to prepare the sub-perovskite film, (1) The evaporation temperature is 100°C to 300°C; (2) the deposition distance is 10 cm to 50 cm, and optionally, the deposition distance is 10 cm to 30 cm; (3) Vacuum degree is (0.5 to 3) x 10 －６ mbar; (4) In the deposition process, the substrate adopts a rotation mode, and the substrate temperature is 15°C to 30°C; (5) The method for producing a perovskite solar cell according to claim 11, further comprising an annealing step after completing the deposition of the multiple layers of sub-perovskite films, and optionally satisfying at least one of the following characteristics as annealing conditions: temperature is 110°C to 140°C, and time is 3 to 20 minutes.

13. 13. The method for producing a perovskite solar cell according to any one of claims 10 to 12, wherein the band gaps of the multiple layers of sub-perovskite films change in order of increasing band gap, and optionally, the bottom electrode is a transparent electrode, and along a direction from the bottom electrode to the top electrode, the band gaps of the multiple layers of sub-perovskite films change in order of increasing band gap.

14. The method for producing a perovskite solar cell according to any one of claims 10 to 13, wherein the number of layers of the sub-perovskite film is 2 to 10 layers, optionally the number of layers of the sub-perovskite film is 2 to 5 layers, and further optionally the number of layers of the sub-perovskite film is 2 to 3 layers.

15. The method for producing a perovskite solar cell according to any one of claims 10 to 14, characterized in that the band gap difference between the adjacent two sub-perovskite films is 0.01 eV to 0.5 eV, optionally, the band gap difference between the adjacent two sub-perovskite films is 0.05 eV to 0.2 eV, and further optionally, the band gap difference between the adjacent two sub-perovskite films is 0.08 eV to 0.12 eV.

16. The multi-layer sub-perovskite film includes at least one wide band gap layer and one narrow band gap layer, and the band gap G of the wide band gap layer is ｗ is 1.2 eV to 2.0 eV, and the band gap G of the narrow band gap layer ｎ is between 0.8 eV and 1.8 eV, and G ｎ ≦G ｗ The method for producing a perovskite solar cell according to any one of claims 10 to 15,

17. The method for producing a perovskite solar cell according to any one of claims 10 to 16, wherein the sub-perovskite film has a thickness of 200 nm to 2 μm, optionally, the sub-perovskite film has a thickness of 300 nm to 1 μm, and further optionally, the sub-perovskite film has a thickness of 300 nm to 600 nm.

18. The material of the sub-perovskite film is selected from one or more compounds represented by the following general structural formula (I): A.B.X. ３ (I) wherein A represents one or a mixture of cations, optionally A includes one or more of the following: methylamine cation, formamidine cation, and cesium ion; B represents a cation or mixture of cations, optionally B comprises a metal cation or mixture of metal cations, further optionally B is Pb ２＋ , Sn ２＋ and Ge ２＋ One or more of the following: X represents a halogen anion or a mixture of halogen anions, optionally X is Cl － , B － and I － The method for producing a perovskite solar cell according to any one of claims 10 to 17, characterized in that the method comprises one or more of the following:

19. A power consuming device comprising a perovskite solar cell selected from the perovskite solar cell according to any one of claims 1 to 9, or a perovskite solar cell produced by the method according to any one of claims 10 to 18.

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