Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof, the perovskite solar cell comprises a substrate, an electron transport layer, a perovskite absorption layer, a hole transport layer and a first electrode which are stacked in sequence, the electron transport layer comprises a compact layer and a mesoporous layer which are stacked, the mesoporous layer is in contact with the perovskite absorption layer, and the hole transport layer is in contact with the compact layer. The material of the mesoporous layer comprises a metal oxide added with a phosphorus compound. The problem that the performance of a solar cell is affected due to poor interface contact between an electron transport layer and a perovskite layer in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of solar cells, and more specifically, to a perovskite solar cell and a method for preparing the same. Background Art

[0002] Perovskite cells, a novel third-generation solar cell, have attracted widespread attention in the photovoltaic field in recent years. They utilize perovskite-type organometallic halide semiconductors as light-absorbing materials and exhibit exceptional optoelectronic properties, such as high optical bandgap tunability, high absorption coefficients, and long carrier diffusion lengths. These properties enable perovskite cells to achieve theoretical efficiencies far exceeding those of traditional crystalline silicon cells, while also offering the potential for lower costs.

[0003] The contact between the electron transport layer (ETL) and the perovskite layer directly impacts the performance and stability of perovskite solar cells. When contact between the two is poor, photogenerated electrons are prone to recombination at the interface during transport, reducing charge collection efficiency and increasing energy loss during charge transport. Furthermore, defects and recombination centers are susceptible to water and oxygen permeation, exacerbating the decomposition of the perovskite to form PbI2, further impacting device performance. Currently, the main approach is to improve the contact between the ETL and the perovskite layer by introducing an interfacial layer and adjusting its thickness and composition. The interfacial layer can passivate defects, reduce recombination, and improve electron transport efficiency. However, the introduction of an interfacial layer inevitably increases process steps, and most interfacial passivation materials are expensive, increasing costs. Another approach is to optimize the contact by selecting an ETL material with high conductivity, stability, and good interfacial compatibility. However, a single ETL material is often prone to structural defects, further impacting the material's electrical performance and stability. Summary of the Invention

[0004] The present application provides a perovskite solar cell and a preparation method thereof, so as to solve the problem in the related art that poor interface contact between an electron transport layer and a perovskite layer affects the performance of the solar cell.

[0005] According to one aspect of the present application, a perovskite solar cell is provided, comprising a substrate, an electron transport layer, a perovskite absorption layer, a hole transport layer and a first electrode stacked in sequence, wherein the electron transport layer comprises a dense layer and a mesoporous layer stacked in sequence, the mesoporous layer is in contact with the perovskite absorption layer, and the material of the mesoporous layer comprises a metal oxide added with a phosphorus compound.

[0006] Optionally, the phosphorus compound includes one or more of sodium pyrophosphate, potassium pyrophosphate, sodium metaphosphate, potassium metaphosphate, potassium orthophosphate, magnesium calcium phosphate, aluminum phosphate, potassium dihydrogen phosphate, ammonium phosphate and ammonium orthophosphate.

[0007] Optionally, a thickness of the mesoporous layer along a stacking direction is greater than a thickness of the dense layer along the stacking direction, wherein the stacking direction is a direction from the substrate to the first electrode.

[0008] Optionally, the mesoporous layer includes a plurality of pores, and the pores are filled with an organic material containing methyl groups and ammonium groups.

[0009] Optionally, the perovskite absorption layer includes a first film layer and a second film layer, the first film layer is in contact with the mesoporous layer, the material of the first film layer includes an organic material containing methyl and ammonium groups, and the material of the second film layer includes an inorganic material.

[0010] Optionally, the organic material containing methyl and ammonium groups includes potassium amidine lead iodide and methylammonium lead iodide.

[0011] According to another aspect of the present application, a method for preparing a perovskite solar cell is provided, comprising: providing a substrate; sequentially forming a stacked dense layer, a mesoporous layer, a perovskite absorption layer, a hole transport layer and a first electrode on the substrate, wherein the dense layer and the mesoporous layer constitute an electron transport layer, and the material of the mesoporous layer comprises a metal oxide material to which a phosphorus-based compound is added.

[0012] Optionally, the step of forming the electron transport layer includes: depositing the dense layer and the mesoporous layer in sequence on the substrate, the mesoporous layer including a plurality of pores; and filling the pores with a first gaseous organic material using a first evaporation process, wherein the first organic material includes an organic material containing methyl and ammonium groups.

[0013] Optionally, the step of forming the perovskite absorption layer includes: using at least a second evaporation process to deposit a gaseous second organic material on the mesoporous layer to form a first film layer, wherein the second organic material includes an organic material containing methyl and ammonium groups; using a third evaporation process to deposit a gaseous inorganic material on the first film layer to form a second film layer, wherein the first film layer and the second film layer constitute the perovskite absorption layer.

[0014] Optionally, a plating rate of the second evaporation process is greater than a plating rate of the first evaporation process.

[0015] The technical solution of the present application is applied to provide a perovskite solar cell, in which an electron transport layer is composed of a dense layer and a mesoporous layer. The dense layer is a non-porous, continuous, and dense thin film that provides an efficient, continuous path for the collection and transmission of photogenerated electrons in the perovskite solar cell, serving as the primary channel for electrons from the perovskite layer to the bottom electrode. The mesoporous layer promotes rapid electron transport and reduces recombination losses during electron transport. The addition of an inorganic phosphorus compound enables the phosphate ions in the compound to embed into the mesoporous material, forming coordination bonds with cations in the perovskite, microscopically regulating the growth of the perovskite crystals, enhancing structural stability, and improving interfacial properties, thereby facilitating rapid electron collection and transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0017] Figure 1 Schematic diagram of the cross-sectional structure of a single-section perovskite solar cell according to an embodiment of the present application;

[0018] Figure 2 is a schematic cross-sectional structure diagram of a stacked perovskite solar cell according to an embodiment of the present application;

[0019] Figure 3 This is a flow chart of a method for preparing a perovskite solar cell according to an embodiment of the present application.

[0020] The above drawings include the following reference numerals:

[0021] 10. Substrate; 111. Bottom TCO film layer; 112. First hydrogenated amorphous silicon layer; 1131. First intrinsic hydrogenated amorphous silicon layer; 1132. Second intrinsic hydrogenated amorphous silicon layer; 114. Single crystal silicon layer; 115. Second hydrogenated amorphous silicon layer; 116. Second electrode; 20. Electron transport layer; 21. Dense layer; 22. Mesoporous layer; 30. Perovskite absorption layer; 31. First film layer; 32. Second film layer; 40. Hole transport layer; 50. First electrode; 60. Bottom electrode; 70. Tunneling layer. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] As described in the background art, the contact problem between the electron transport layer and the perovskite layer in the prior art is directly related to the performance and stability of perovskite solar cells. When the two are in poor contact, photogenerated electrons are easily recombined at the interface during transmission, resulting in reduced charge collection efficiency and increased energy loss during charge transmission. At the same time, defects and recombination centers are easily permeated with water and oxygen, exacerbating the decomposition of perovskite to form PbI2, further affecting device performance. To address the above problems, the present application provides a perovskite solar cell and a method for preparing the same.

[0026] According to one aspect of the present application, a perovskite solar cell is provided, such as Figures 1 to 2As shown, it includes a substrate 10, an electron transport layer 20, a perovskite absorption layer 30, a hole transport layer 40 and a first electrode 50 stacked in sequence, wherein the electron transport layer 20 includes a dense layer 21 and a mesoporous layer 22 stacked in layers, the mesoporous layer 22 is in contact with the perovskite absorption layer 30, and the material of the mesoporous layer 22 includes a metal oxide added with a phosphorus compound, and the density of the dense layer 21 is greater than the density of the mesoporous layer 22. In this perovskite solar cell, the electron transport layer 20 is composed of the dense layer 21 and the mesoporous layer 22, wherein the dense layer 21 is a non-porous, continuous and dense film, which provides an efficient and continuous path for the collection and transmission of photogenerated electrons for the perovskite solar cell, and is the main channel for electrons from the perovskite layer to the FTO bottom electrode. The mesoporous layer 22 can promote the rapid transmission of electrons and reduce the composite loss of electrons during the transmission process. The addition of inorganic phosphorus compounds enables the phosphate ions in the compound to be embedded in the mesoporous material, forming coordination bonds with the cations in the perovskite, microscopically regulating the growth of the perovskite crystals, enhancing the stability of the structure, improving the interface performance, and facilitating the rapid collection and transmission of electrons.

[0027] In some optional embodiments, the perovskite solar cell is as follows Figure 1 The perovskite single-cell solar cell shown, wherein the substrate 10 may include a glass substrate, specifically, the perovskite solar cell may include FTO conductive glass, ITO conductive glass, AZO conductive glass and a conductive flexible substrate. A bottom electrode 60 is provided between the substrate 10 and the electron transport layer 20, wherein the electron transport layer 20 includes a dense layer 21 and a mesoporous layer 22 arranged in a stacked manner, wherein the mesoporous layer 22 is in contact with the perovskite absorption layer 30, and the material of the mesoporous layer 22 includes a metal oxide with a phosphorus compound added to form a perovskite single-cell solar cell structure. The preparation process of the perovskite single-cell solar cell is mature, which can achieve large-area preparation and has high stability.

[0028] Specifically, the material of the bottom electrode includes but is not limited to one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO) and zinc-doped tin oxide (ZTO). The bottom electrode can transfer electrons through the electron transport layer, thereby generating current.

[0029] In other optional embodiments, the perovskite solar cell in the present application is a perovskite stacked solar cell structure, wherein the substrate is a solar bottom cell, wherein the solar bottom cell includes an intrinsic thin film heterojunction (Heterojunction with Intrinsic Thin-film, abbreviated as HJT) bottom cell, i.e., a solar crystalline silicon bottom cell, an oxide layer passivated contact (Tunnel Oxide Passivated Contact, abbreviated as Topcon) bottom cell, an interdigitated back contact (Interdigitated Back Contact, abbreviated as IBC) bottom cell and an ABC bottom cell.

[0030] For example, Figure 2 As shown, the substrate 10 in the perovskite solar cell can be an HJT bottom cell, which may include: an underlying TCO film layer 111 and a first hydrogenated amorphous silicon layer 112, a first intrinsic hydrogenated amorphous silicon layer 1131, a single crystal silicon layer 114, a second intrinsic hydrogenated amorphous silicon layer 1132 and a second hydrogenated amorphous silicon layer 115 formed on the first surface of the underlying TCO film layer 111 in sequence and perpendicular to the first surface. The surface of the second hydrogenated amorphous silicon layer 115 facing away from the underlying TCO film layer 111 is the bottom cell, that is, the front side of the substrate 10. The solar bottom cell may further include a second electrode 116 formed on the back side of the underlying TCO film layer 111.

[0031] In the above example, if Figure 2 As shown, a tunneling layer 70 is required to electrically connect the crystalline silicon bottom cell and the perovskite cell. The material of the tunneling layer 70 includes, but is not limited to, one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO), and zinc-doped tin oxide (ZTO). It effectively recombines electrons and holes with minimal resistance loss and ensures high optical transparency in the long-wave band.

[0032] In some optional embodiments, the phosphorus compound includes one or more of sodium pyrophosphate, potassium pyrophosphate, sodium metaphosphate, potassium metaphosphate, potassium orthophosphate, magnesium calcium phosphate, aluminum phosphate, potassium dihydrogen phosphate, ammonium phosphate and ammonium orthophosphate.

[0033] Specifically, the above-mentioned phosphorus compounds are relatively stable in chemical properties and have good compatibility with perovskite materials and mesoporous layer materials. They can be embedded in mesoporous materials and form coordination bonds with cations in the perovskite layer without causing decomposition of the material or incompatible chemical reactions. Among them, the phosphate ions in the phosphorus compounds can passivate defects in the perovskite layer and reduce non-radiative recombination. In addition, the phosphorus compounds affect the growth and morphology of the crystals by controlling the crystallization process of the perovskite material, thereby improving the carrier lifetime and reducing energy loss. Among the above-mentioned phosphorus compounds, such as sodium pyrophosphate and potassium pyrophosphate, have good electronic conductivity, which can further optimize the electron transfer efficiency of the mesoporous layer, thereby improving the overall battery performance. In addition, compared with complex organic or metal organic materials, the above-mentioned phosphorus compounds have lower costs and are easier to mass produce, effectively reducing production costs.

[0034] In some optional embodiments, such as Figures 1 to 2 As shown, the thickness H2 of the mesoporous layer 22 along the stacking direction A is greater than the thickness H1 of the dense layer 21 along the stacking direction A, wherein the stacking direction A is the direction from the substrate 10 to the first electrode 50 .

[0035] Specifically, while the mesoporous layer serves as an efficient electron transmission channel, it also has a larger surface area due to its large number of voids, which is conducive to the deep penetration and uniform distribution of the perovskite material, increasing the separation and collection area of ​​photogenerated charges, thereby improving the charge collection efficiency and the short-circuit current of the battery. While the mesoporous layer has a relatively thick thickness, it can provide an electron transmission channel and accelerate the transmission of electrons from the perovskite absorption layer to the electrode, effectively increasing the surface area of ​​the mesoporous layer, which is conducive to the deep penetration and uniform distribution of the perovskite material, increasing the separation and collection area of ​​photogenerated charges, thereby improving the charge collection efficiency and the short-circuit current of the battery. In addition, the thicker mesoporous layer can provide more sufficient growth space for the growth of perovskite crystals, improve the uniformity and stability of the perovskite absorption layer, and enhance the photoelectric conversion efficiency of the battery. In addition, the inorganic phosphorus compound added to the mesoporous layer is more fully embedded and exerts its effect in the thicker dielectric layer, improving the interface contact between the perovskite layer and the electron transport layer, reducing interface defects, and enhancing interface stability.

[0036] The thickness of the dense layer is 30 to 50 nm, and the thickness of the mesoporous layer is 100 to 150 nm, which is not specifically limited in this application.

[0037] In some optional embodiments, the mesoporous layer includes a plurality of pores, and the pores are filled with an organic material containing methyl groups and ammonium groups.

[0038] Specifically, the mesoporous layer is composed of metal oxides, which are formed into a porous structure with multiple pores through a specific deposition and heat treatment process, wherein the metal oxides include but are not limited to materials such as TiO2, SnO2 and Al2O3. The pores in the mesoporous layer provide channels for the penetration of perovskite materials, increase the contact area between the perovskite layer and the electron transport layer, and are beneficial to improving the collection efficiency of photogenerated charges. In addition, the porous structure in the mesoporous layer can promote the rapid transmission of electrons and reduce the composite loss of electrons during the transmission process. The addition of inorganic phosphorus compounds further improves the electron transmission efficiency and interface stability, which is beneficial to the rapid collection and transmission of electrons. At the same time, the phosphorus compounds form coordination bonds with the cations in the perovskite layer, which can regulate the growth of perovskite crystals, strengthen the bonding between the perovskite and the electron transport layer, microscopically regulate the crystal structure, and improve the overall charge transmission and collection efficiency.

[0039] In addition, organic materials containing methyl and ammonium groups can be used as materials for the perovskite absorption layer. After the organic materials containing methyl and ammonium groups are filled in the gaps, the perovskite absorption layer is formed so that the mesoporous layer is in contact with the perovskite absorption layer. The organic materials containing methyl and ammonium groups in the mesopores can also act as a light-absorbing layer, increasing the contact area between the perovskite layer and the electron transport layer, which is beneficial to improving the collection efficiency of photogenerated charges. Moreover, the phosphorus-based compounds form coordination bonds with the cations in the perovskite layer, which can regulate the growth of perovskite crystals, strengthen the bonding between the perovskite and the electron transport layer, microscopically regulate the crystal structure, and improve the overall charge transport and collection efficiency.

[0040] In some optional embodiments, such as Figures 1 to 2 As shown, the perovskite absorption layer 30 includes a first film layer 31 and a second film layer 32. The first film layer 31 contacts the mesoporous layer 22. The material of the first film layer 31 includes an organic material containing methyl and ammonium groups, and the material of the second film layer 32 includes an inorganic material.

[0041] Specifically, the film layer in contact with the mesoporous layer in the perovskite absorption layer is an organic perovskite layer, and the film layer located on the side of the first film layer away from the mesoporous layer is an inorganic perovskite layer. The organic perovskite layer can fill the pores of the mesoporous electron transport layer to form a good interface contact. The strong dispersibility of the organic perovskite layer enables it to be more evenly distributed, filling the micropores of the mesoporous layer, reducing interface recombination, and improving the charge collection efficiency. The inorganic perovskite layer can optimize the electron transport path and improve the electron transport efficiency. It can also work in conjunction with the organic layer to improve the overall electron transport characteristics. In addition, the organic material can passivate the defects in the inorganic perovskite layer and reduce non-radiative recombination, thereby improving the carrier life and battery stability. The organic perovskite layer can serve as a template for the growth of the inorganic perovskite layer, helping to guide the uniform growth of the inorganic perovskite crystals, forming a more dense and stable perovskite film, thereby improving the photoelectric conversion efficiency of the solar cell and extending the service life.

[0042] In some specific embodiments, the first film layer may include multiple sub-film layers of organic materials, and the second film layer may also include multiple sub-film layers of inorganic materials, so as to achieve functional adjustment of each film layer to improve the overall performance of the battery.

[0043] Among them, the inorganic material includes but is not limited to one or more of PbI2, PbCl2, PbBr2, CsI, CsCl and CsBr, and is not specifically limited in this application.

[0044] In some alternative embodiments, the organic material comprising methyl and ammonium groups includes potassium amidine lead iodide and methylammonium lead iodide.

[0045] Specifically, the structural crystal form of the perovskite material is ABX3 type, in which the A and B positions are occupied by organic and inorganic cations respectively, and the X position is occupied by halogen anions. This structure gives the perovskite material good photoelectric properties. In addition, by adjusting the organic component or adjusting the ratio of organic and inorganic components, the material's band gap and carrier lifetime and other properties can be fine-tuned to adapt to different spectra and improve efficiency. The molecular formula of formamidinium lead iodide (FAI) is HC(NH2)2PbI3, which is a type of ABX3 perovskite structure, in which the A position is formamidinium (HC(NH2) 2+ ), B position is lead (Pb 2 + ), X is iodine (I - ), FAI includes a methyl group and two amino groups. Methylammonium Lead Iodide (MAI), whose chemical formula is CH3NH3PbI3, MAI also belongs to the ABX3 type perovskite structure, in which the A position is a methylammonium cation (CH3NH 3+), B position is lead (Pb 2+ ), X is iodine (I - ), MAI contains a methyl group and an ammonium group. Potassium amidine lead iodide or methylammonium lead iodide is used as the organic material for preparing the perovskite light-absorbing layer. Both are filled into the voids of the mesoporous layer. The potassium amidine lead iodide or methylammonium lead iodide filled in the voids function as a perovskite light-absorbing layer, thereby increasing the contact area between the electron transport layer and the perovskite layer, and strengthening the interfacial bonding and adhesion between the electron transport layer and the perovskite layer.

[0046] Furthermore, FAI and MAI possess strong diffusion capabilities, allowing them to be more evenly distributed throughout the mesoporous layer and penetrate the pores of the mesoporous layer, forming a denser contact interface and better bonding with the metal oxide material in the mesoporous layer, thereby improving charge transfer efficiency. Furthermore, by leveraging FAI's strong diffusion properties, the staged evaporation process ensures the efficient filling of the mesoporous material, and the constructive reaction during annealing and crystallization after evaporation of the inorganic salt further optimizes the interface properties, improving the quality of the perovskite film and the performance of the battery.

[0047] According to another aspect of the present application, a method for preparing a perovskite solar cell is provided, such as Figure 3 Shown, including:

[0048] Step S201: providing a substrate;

[0049] Step S202: forming a stacked dense layer, a mesoporous layer, a perovskite absorption layer, a hole transport layer and a first electrode in sequence on the substrate, wherein the dense layer and the mesoporous layer constitute an electron transport layer, and the material of the mesoporous layer includes a metal oxide material added with a phosphorus compound.

[0050] Using the above-mentioned perovskite solar cell preparation method of the present application, a dense layer and a mesoporous layer are formed on the substrate. The dense layer and the mesoporous layer constitute an electron transport layer. The dense layer is a non-porous, continuous, and dense film that provides an efficient and continuous path for the collection and transmission of photogenerated electrons in the perovskite solar cell and is the main channel for electrons to pass from the perovskite layer to the bottom electrode. The mesoporous layer can promote the rapid transmission of electrons and reduce the composite loss of electrons during the transmission process. The addition of the inorganic phosphorus compound enables the phosphate ions in the compound to embed into the mesoporous material and form coordination bonds with the cations in the perovskite. This microscopically regulates the growth of the perovskite crystals, enhances the stability of the structure, improves the interface performance, and facilitates the rapid collection and transmission of electrons.

[0051] The following is a more detailed description of exemplary embodiments of the method for preparing a perovskite solar cell according to the present application, in conjunction with the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of this application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0052] To get Figures 1 to 2 The structure of the perovskite solar cell shown in FIG. 1 includes firstly performing step S201 : providing a substrate.

[0053] Exemplarily, the substrate may include a glass substrate, specifically, the glass substrate may include FTO conductive glass, ITO conductive glass, AZO conductive glass, or a conductive flexible substrate. As another example, the substrate may also include a solar crystalline silicon bottom cell of an HTJ bottom cell, specifically, the crystalline silicon bottom cell includes: an underlying TCO film layer, and a first hydrogenated amorphous silicon layer, a first intrinsic hydrogenated amorphous silicon layer, a single crystal silicon layer, a second intrinsic hydrogenated amorphous silicon layer, and a second hydrogenated amorphous silicon layer stacked and arranged in sequence perpendicular to the first surface on a first surface of the underlying TCO film layer. The surface of the second hydrogenated amorphous silicon layer facing away from the underlying TCO film layer is the bottom cell, i.e., the front side of the substrate. The solar bottom cell may also include a second electrode formed on the back side of the underlying TCO film layer.

[0054] In a single-cell solar cell, Figure 1 As shown, a bottom electrode 60 is formed on the substrate 10. The material of the bottom electrode 60 includes but is not limited to one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO) and zinc-doped tin oxide (ZTO). The bottom electrode can transfer electrons from the electron transport layer to generate current.

[0055] In the perovskite tandem solar cell structure, a tunneling layer is formed on the crystalline silicon bottom cell. The material of the tunneling layer includes but is not limited to one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO) and zinc-doped tin oxide (ZTO). It effectively recombines electrons and holes with minimal resistance loss and ensures high optical transparency in the long-wave band.

[0056] In other embodiments, the substrate may further include a Topcon bottom battery, an IBC bottom battery, and an ABC bottom battery. The preparation methods of the above bottom batteries are the same as those in the prior art, and are not described in detail in this application.

[0057] After providing the substrate, step S202 is performed: a dense layer, a mesoporous layer, a perovskite absorption layer, a hole transport layer and a first electrode are sequentially formed on the substrate, wherein the dense layer and the mesoporous layer constitute an electron transport layer.

[0058] Specifically, the above step S202 may include the following steps:

[0059] First, step S2021 is performed: a dense layer is formed by a deposition process, wherein the material of the dense layer may include but is not limited to SnO2, ZnO, TiO2, PCBM and C 60 The combination of one or more materials is not limited in this application.

[0060] Specifically, the above-mentioned deposition processes include but are not limited to physical vapor deposition (PVD), chemical vapor deposition (CVD) and atomic layer deposition (ALD), among which physical vapor deposition (PVD) includes but is not limited to magnetron sputtering process, reactive sputtering process, DC sputtering process, AC sputtering process, vacuum coating process, arc evaporation process, chemical vapor deposition (CVD) includes but is not limited to plasma enhanced chemical vapor deposition (PECVD), metal organic compound chemical vapor deposition (MOCVD), laser induced chemical vapor deposition (LCVD), and those skilled in the art can make reasonable selections according to actual needs, and no specific limitation is made without application.

[0061] Then, step S2022 is performed: forming a mesoporous layer.

[0062] Specifically, the steps of forming a mesoporous layer include: first, providing a first precursor solution of the mesoporous layer material, the first precursor solution includes a solvent and a solute, wherein the solute includes a phosphorus compound and a compound containing metal ions, and the content of the phosphorus compound is 50 mg / mL to 200 mg / mL, and a mesoporous layer is formed on the substrate by a solution method or a deposition process; then, a first evaporation process is used to evaporate the first organic material to form a gaseous first organic material, and the gaseous first organic material is filled in the pores, wherein the first organic material includes an organic material containing methyl and ammonium groups.

[0063] Specifically, during the process of evaporating the first organic material using the first evaporation process, part of the gaseous first organic material may form a first sub-film layer on the mesoporous layer, and the first sub-film layer may be a perovskite light absorption layer.

[0064] In the above embodiment, an inorganic phosphorus compound is added to the first precursor solution of the mesoporous material. The compound will be embedded in the pores, and the phosphate ions therein will bond with the cations in the perovskite, thereby enhancing the stability of the structure and improving the interface properties between the electronic layer and the perovskite layer.

[0065] Exemplary organic materials containing methyl and ammonium groups include potassium amidine lead iodide. In another example, organic materials containing methyl and ammonium groups include methylammonium lead iodide. Leveraging the strong dispersibility of FAI and MAI, a staged evaporation process ensures efficient filling of the mesoporous material. Furthermore, the constructive reaction during annealing and crystallization after evaporation of the inorganic salt further optimizes interfacial properties, improving the quality of the perovskite film and battery performance.

[0066] Then, step S2023 is performed: forming a perovskite absorption layer.

[0067] Specifically, the steps of forming the perovskite absorption layer include: first, using at least a second evaporation process to evaporate the second organic material into a gaseous state, and forming a first film layer on the mesoporous layer with the gaseous second organic material, wherein the second organic material includes an organic material containing methyl and ammonium groups; then, using a third evaporation process to evaporate the inorganic material into a gaseous state, and forming a second film layer on the first film layer with the gaseous inorganic material, wherein the first film layer and the second film layer constitute the perovskite absorption layer.

[0068] In some specific embodiments, the first film layer may include multiple sub-film layers of organic materials, and the second film layer may also include multiple sub-film layers of inorganic materials, so as to achieve functional adjustment of each film layer to improve the overall performance of the battery.

[0069] In some optional embodiments, the plating rate of the second evaporation process is greater than the plating rate of the first evaporation process.

[0070] Specifically, the plating rate of the second evaporation process is The plating rate of the first evaporation process is The strong diffusibility of the first organic material during evaporation allows it to more easily fill the pores of the mesoporous layer, increasing contact with the mesoporous electron layer and strengthening the interfacial bonding and adhesion. The first evaporation process uses a low plating rate mode to ensure that the first organic material effectively fills the pores of the mesoporous layer. The second evaporation process increases the plating rate. Using a high plating rate evaporation process to form the first perovskite film can save process time and cost.

[0071] Then, step S2024 is performed: forming a hole transport layer.

[0072] Specifically, the materials of the hole transport layer include but are not limited to one or more of Spiro-OMeTAD, 2PACz, Me-2PACz, MeO-2PACz, Me-4PACz and MeO-4PACz, and this application does not make specific restrictions. The process methods for preparing the hole transport layer 40 include but are not limited to spin coating, evaporation and chain immersion methods, and this application does not make specific restrictions.

[0073] Exemplarily, the steps of preparing a hole transport layer by spin coating include: first, providing a second precursor solution of the hole transport layer material, the second precursor solution including a solvent and a solute, wherein the solute of the second precursor solution includes Spiro-OMeTAD and Li-TFSI powder, and the solvent of the second precursor solution includes chlorobenzene; then, the second precursor solution is coated on the perovskite absorption layer by spin coating to form a hole transport layer.

[0074] Then, step S2025 is performed: forming a first electrode.

[0075] Specifically, the material of the first electrode includes, but is not limited to, a combination of one or more materials selected from Au, Ag, Cu, and Al, which is not specifically limited in this application. The process for forming the first electrode includes, but is not limited to, screen printing, thermal evaporation, and magnetron sputtering.

[0076] The preparation method provided by this application will be further illustrated below with reference to examples.

[0077] Example 1

[0078] Step S11: providing a substrate, wherein one side of the substrate has an FTO bottom electrode;

[0079] Step S12: forming dense TiO2 on the FTO glass layer by a magnetron sputtering process to form a dense layer;

[0080] Step S13: preparing a first precursor solution of the mesoporous layer: mixing 0.2 g of potassium orthophosphate and 1 ml of titanium tetraisopropoxide in a solvent comprising 10 ml of 28% concentrated hydrochloric acid and 9 ml of deionized water, and magnetically stirring for 24 h;

[0081] Step S14: preparing a mesoporous layer by a solution method: placing the substrate including the dense layer and the first precursor solution into a hydrothermal reactor, reacting at 200°C for 3 hours, removing the substrate, rinsing the surface with ethanol, and then annealing at 450°C for 30 minutes to form a mesoporous layer;

[0082] Step S15: Using a plating rate of The FAI is evaporated by an evaporation process to form a first sub-film layer with a thickness of 50 nm on the mesoporous layer;

[0083] Step S16: Using a plating rate of The evaporation process continues to evaporate FAI to form a second sub-film layer with a thickness of 300 nm on the first sub-film layer. The first sub-film layer and the second sub-film layer constitute a first film layer.

[0084] Step S17: Using a plating rate of PbI2 is evaporated by an evaporation process to form a third sub-film layer on the first film layer;

[0085] Step S18: Using a plating rate of CsBr is evaporated by an evaporation process to form a fourth sub-film layer on the third sub-film layer, and the third sub-film layer and the fourth sub-film layer constitute a second film layer;

[0086] Step S19: dissolving the Spiro-OMeTAD and Li-TFSI powders in chlorobenzene solvent to form a second precursor solution, and spin-coating the second precursor solution on the second film layer at a speed of 3000 rpm for 30 seconds to form a Spiro-OMeTAD layer on the second film layer to form a hole transport layer;

[0087] Step S110 : forming an Ag layer on the hole transport layer by a thermal evaporation process to form a first electrode.

[0088] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0089] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A perovskite solar cell, characterized in that It includes a substrate, an electron transport layer, a perovskite absorption layer, a hole transport layer and a first electrode stacked in sequence, wherein the electron transport layer includes a dense layer and a mesoporous layer stacked in sequence, the mesoporous layer is in contact with the perovskite absorption layer, and the material of the mesoporous layer includes a metal oxide added with a phosphorus compound.

2. The perovskite solar cell according to claim 1, characterized in that The phosphorus compound includes one or more of sodium pyrophosphate, potassium pyrophosphate, sodium metaphosphate, potassium metaphosphate, potassium orthophosphate, magnesium calcium phosphate, aluminum phosphate, potassium dihydrogen phosphate, ammonium phosphate and ammonium orthophosphate.

3. The perovskite solar cell according to claim 1, wherein The thickness of the mesoporous layer along the stacking direction is greater than the thickness of the dense layer along the stacking direction, wherein the stacking direction is a direction from the substrate to the first electrode.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that The mesoporous layer includes a plurality of pores, and the pores are filled with an organic material containing methyl groups and ammonium groups.

5. The perovskite solar cell according to claim 4, characterized in that The perovskite absorption layer includes a first film layer and a second film layer, the first film layer is in contact with the mesoporous layer, the material of the first film layer includes an organic material containing methyl and ammonium groups, and the material of the second film layer includes an inorganic material.

6. The perovskite solar cell according to claim 4, characterized in that The organic materials containing methyl and ammonium groups include potassium amidine lead iodide and methylammonium lead iodide.

7. A method for preparing a perovskite solar cell, characterized in that: include: providing a substrate; A dense layer, a mesoporous layer, a perovskite absorption layer, a hole transport layer and a first electrode are sequentially formed on the substrate, wherein the dense layer and the mesoporous layer constitute an electron transport layer, and the material of the mesoporous layer includes a metal oxide material added with a phosphorus compound.

8. The preparation method according to claim 7, characterized in that The steps of forming the electron transport layer include: Depositing the dense layer and the mesoporous layer in sequence on the substrate, wherein the mesoporous layer includes a plurality of pores; A first organic material in a gaseous state is filled into the pores by a first evaporation process, wherein the first organic material includes an organic material containing a methyl group and an ammonium group.

9. The preparation method according to claim 8, characterized in that The steps of forming the perovskite absorption layer include: Depositing a gaseous second organic material on the mesoporous layer to form a first film layer by at least a second evaporation process, wherein the second organic material includes an organic material containing a methyl group and an ammonium group; A third evaporation process is used to deposit a gaseous inorganic material on the first film layer to form a second film layer, wherein the first film layer and the second film layer constitute the perovskite absorption layer.

10. The preparation method according to claim 9, characterized in that A plating rate of the second evaporation process is greater than a plating rate of the first evaporation process.

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