A perovskite solar cell and its fabrication method

Abstract

This invention relates to the field of perovskite solar cell technology, and provides a perovskite solar cell and its fabrication method. The perovskite solar cell includes: a transparent conductive layer; an H-TiO2 layer disposed on the transparent conductive layer; a perovskite absorber layer disposed on the H-TiO2 layer; a hole transport layer disposed on the perovskite absorber layer; and an electrode disposed on the hole transport layer. The perovskite solar cell provided by this invention, by setting an H-TiO2 layer as an electron transport layer between the transparent conductive layer and the perovskite absorber layer, significantly reduces the band gap and improves the conductivity of the electron transport layer compared to a traditional TiO2 electron transport layer, thereby improving the efficiency of the perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, specifically to a perovskite solar cell and its fabrication method. Background Technology

[0002] Perovskite solar cells have attracted widespread attention due to their excellent photoelectric properties, including tunable bandgap, high light absorption coefficient, long carrier lifetime and diffusion length, high defect tolerance, and low-cost low-temperature liquid-phase fabrication methods. As perovskite solar cells continue to develop, effectively improving their cell efficiency has become a pressing issue.

[0003] In existing technologies, perovskite solar cells generally include a transparent conductive layer, an electron transport layer, a perovskite absorber layer, a hole transport layer, and an electrode arranged sequentially from bottom to top. Perovskite solar cells typically use titanium dioxide as the electron transport layer. Due to the large band gap of the titanium dioxide electron transport layer, the conductivity of the titanium dioxide electron transport layer is poor. The cell efficiency of perovskite solar cells is limited by the conductivity of the electron transport layer, resulting in low cell efficiency of perovskite solar cells. Summary of the Invention

[0004] This invention provides a perovskite solar cell, aiming to solve the problem of low efficiency in existing perovskite solar cells due to poor conductivity of the electron transport layer.

[0005] This invention is implemented as follows: a perovskite solar cell is provided, comprising:

[0006] Transparent conductive layer;

[0007] An H-TiO2 layer disposed on the transparent conductive layer;

[0008] A perovskite absorber layer disposed on the H-TiO2 layer;

[0009] A hole transport layer disposed above the perovskite absorber layer; and

[0010] An electrode disposed on the hole transport layer.

[0011] Preferably, the thickness of the H-TiO2 layer is 50–60 nm.

[0012] Preferably, the perovskite absorber layer is prepared by reacting a perovskite crystal with a MOF material doped with metal R atoms. The perovskite crystal has the structural formula PbMAX3, where X is one or more of F, Cl, Br, and I. The MOF material doped with metal R atoms has the structural formula C8H. 10 N4U 1-y Ry U and R are one or more of Zn, Ni, Fe, Co, Cu or rare earth metals, and U and R are different from each other, wherein the mass fraction of R is less than the mass fraction of U.

[0013] Preferably, the mass fraction of U is 15-40%, and the mass fraction of R is 0.5-10%. Preferably, the PbMAX3 and C8H... 10 N4U 1-y R y The ratio of the number of moles is 0.5 to 5.

[0014] Preferably, the perovskite crystal is encapsulated within the framework of the MOF material or attached to the surface of the MOF material framework, the doped metal R atoms are uniformly distributed within the MOF material framework, and the doped metal R atoms form chemical bonds with the non-metals of the MOF material.

[0015] This invention also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0016] An H-TiO2 layer was prepared on a transparent conductive layer;

[0017] A perovskite absorber layer is prepared on the H-TiO2 layer;

[0018] A hole transport layer is prepared on the perovskite absorber layer;

[0019] Electrodes are fabricated on the hole transport layer.

[0020] Preferably, the step of preparing the H-TiO2 layer on the transparent conductive layer includes:

[0021] A TiO2 film is formed on the transparent conductive layer;

[0022] The transparent conductive layer forming the TiO2 film is placed in a tube furnace and H2 is introduced into the tube furnace. The furnace is sintered at 400-600°C for 20-50 minutes to inject H into the TiO2 film to form the H-TiO2 layer.

[0023] Preferably, the step of forming a TiO2 film on the transparent conductive layer includes:

[0024] Preparation of precursor solution: Add ethanol / water solution dropwise to a mixed solution of ethanol:diethanolamine:tetrabutyl titanate silicon in a volume ratio of 12-15:1-3:3-5 to prepare a precursor solution;

[0025] Preparation of TiO2 film: The transparent conductive layer is immersed in the precursor solution, and the transparent conductive layer is pulled out of the precursor solution at a constant speed and dried to form a TiO2 film on the transparent conductive layer.

[0026] Preferably, the thickness of the H-TiO2 layer is 50–60 nm.

[0027] The present invention provides a perovskite solar cell by setting an H-TiO2 layer as an electron transport layer between a transparent conductive layer and a perovskite absorber layer. The H-TiO2 layer replaces the traditional TiO2 electron transport layer. Compared with the traditional TiO2 electron transport layer, the band gap of the H-TiO2 formed by H injection is significantly smaller than that of TiO2. Therefore, H-TiO2 as an electron transport layer can significantly reduce the band gap, thereby improving the conductivity of the electron transport layer and thus improving the efficiency of the perovskite solar cell. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present invention;

[0029] Figure 2 This is a flowchart illustrating a method for fabricating a perovskite solar cell according to an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] The perovskite solar cell provided in this invention uses an H-TiO2 layer as an electron transport layer between a transparent conductive layer and a perovskite absorber layer. By using the H-TiO2 layer to replace the traditional TiO2 electron transport layer, the H-TiO2 layer formed by H injection can significantly reduce the band gap of the electron transport layer, thereby improving the conductivity of the electron transport layer and thus improving the efficiency of the perovskite solar cell.

[0032] Please refer to Figure 1 This invention provides a perovskite solar cell, comprising:

[0033] Transparent conductive layer 1;

[0034] An H-TiO2 layer 2 is disposed on top of a transparent conductive layer 1;

[0035] Perovskite absorber layer 3 is disposed on top of H-TiO2 layer 2;

[0036] Hole transport layer 4 disposed above perovskite absorber layer 3; and

[0037] Electrode 5 is disposed on the hole transport layer 4.

[0038] In this embodiment of the invention, the specific structure of the transparent conductive layer 1 may include a transparent glass substrate and a transparent conductive film arranged sequentially from bottom to top. The transparent glass substrate is used to transmit sunlight, and the transparent conductive film is used for both light transmission and electrical conductivity.

[0039] As an embodiment of the present invention, the transparent conductive film can be any one of ITO film, FTO film, IWO film, IWO film, and ICO film. In practical applications, any one of ITO film, FTO film, IWO film, IWO film, and ICO film can be selected.

[0040] In this embodiment of the invention, the H-TiO2 (hydrogenated titanium dioxide) layer 2 serves as the electron transport layer of the perovskite solar cell. Since the H-TiO2 layer 2 can significantly reduce the band gap as an electron transport layer, it can improve the conductivity of the electron transport layer and thus improve the efficiency of the perovskite solar cell.

[0041] In one embodiment of the present invention, the thickness of the H-TiO2 layer 2 is 50-60 nm, which ensures good conductivity while avoiding any impact on the absorption of sunlight by the perovskite solar cell. The specific thickness of the H-TiO2 layer 2 can be set according to actual conditions; for example, the thickness of the H-TiO2 layer 2 can be 50 nm, 55 nm, 60 nm, etc.

[0042] In one embodiment of the present invention, the perovskite absorber layer 3 is prepared by reacting a perovskite crystal with a MOF material doped with metal R atoms. The perovskite crystal has the structural formula PbMAX3, where X is one or more of F, Cl, Br, and I. The MOF material doped with metal R atoms has the structural formula C8H. 10 N4U 1-y R y U and R are one or more of Zn, Ni, Fe, Co, Cu or rare earth metals, and U and R are different from each other, wherein the mass fraction of R is less than the mass fraction of U.

[0043] Among them, C8H 10 N4U 1-y R yIn this process, metals U and R form metal-organic frameworks (MOFs) with nonmetals, with U and R uniformly doped within the framework. U and R can be one or more of Zn, Ni, Fe, Co, Cu, or rare earth metals, and each type of U and R is unique. For example, U and R can correspond to Zn and Ni respectively, meaning Ni atoms are doped into the Zn-organic framework. The structural formula of the Ni-doped MOF is C8H. 10 N4Zn 1-y Ni y Rare earth metals can specifically include scandium (Sc), yttrium (Y), lanthanum (La), etc.

[0044] In this embodiment of the invention, the perovskite absorber layer 3 is composed of perovskite crystal (PbMAX3) and MOF material (C8H) doped with metal R atoms. 10 N4U 1-y R y The process involves a one-step reaction. On one hand, the perovskite crystal is uniformly bonded to the MOF material framework. The MOF material framework stabilizes the perovskite crystal structure, and the MOF material acts as an electron donor, increasing the conductivity of the entire perovskite absorber layer 3. This facilitates the separation of charge carriers generated by light and improves the efficiency of perovskite solar cells. On the other hand, metal R atoms are doped into the traditional single metal U metal-organic framework structure of MOF materials, with the mass fraction of R being less than that of U. By doping a small number of metal R atoms, the conductivity and band structure of the MOF material are controlled, promoting the absorption of visible light. Furthermore, the doped metal R atoms have excellent stability, making the perovskite absorber layer 3 more stable and improving the performance of perovskite solar cells.

[0045] In this embodiment of the invention, the metal U and the metal R are different from each other. That is, doping other metal R atoms into the metal U-organic framework of a traditional MOF material can improve the band gap and enhance the light absorption efficiency. For example, if the metal U is Zn, then the metal R is one or more of Ni, Fe, Co, Cu, or rare earth metals.

[0046] In one embodiment of the present invention, the mass fraction of U is 15-40%, and the mass fraction of R is 0.5-10%. The mass fractions of U and R represent percentages of the total mass of the perovskite absorber layer 3. Because the mass fraction of R is 0.5-10% and the mass fraction of U is 15-40%, only trace amounts of metal R atoms are needed to control the conductivity and band structure of the MOF material in the perovskite absorber layer 3, promoting the absorption of visible light while ensuring low cost.

[0047] In this embodiment of the invention, the PbMAX3 and C8H of the perovskite absorber layer 3 are... 10 N4U1-y R y The molar ratio is controlled between 0.5 and 5 to ensure good light absorption and conductivity of the perovskite absorption layer 3. It also ensures that only trace amounts of metal R atoms are doped in the MOF material, thus ensuring the ability to regulate the conductivity and band structure of the MOF material, promoting the absorption of visible light, improving the stability of the perovskite absorption layer 3, and ensuring low cost.

[0048] As an embodiment of the present invention, PbMAX3 and C8H 10 N4U 1-y R y The molar ratio of the perovskite layer is 0.5 to 5, which ensures both good solar absorption performance and good electrical conductivity of the perovskite layer.

[0049] As a preferred embodiment of the present invention, PbMAX3 and C8H 10 N4U 1-y R y The molar ratio is 0.5 to 2, which ensures that the perovskite layer has the best absorption and conductivity properties for sunlight.

[0050] As an embodiment of the present invention, perovskite crystals are encapsulated inside the framework of MOF material or attached to the surface of MOF material framework, and doped metal R atoms are uniformly distributed in MOF material framework, and doped metal R atoms form chemical bonds with non-metals of MOF material.

[0051] In this embodiment, the perovskite absorber layer 3 is composed of perovskite crystal (PbMAX3) and MOF material (C8H) doped with metal R atoms. 10 N4U 1-y R y The perovskite crystals are prepared in a one-step reaction, coating the interior of the MOF material framework or attaching to the surface of the MOF material framework. This allows the perovskite crystals to be uniformly integrated with the MOF material framework, enriching the pore structure of the MOF material. Compared with pure organic or inorganic perovskite, the stability and conductivity of the perovskite absorber layer 3 are greatly improved.

[0052] As an embodiment of the present invention, the MOF material has a dodecahedral structure, with the perovskite crystal located at the body center of the dodecahedral structure and the doped metal R atoms distributed at each vertex of the dodecahedral structure.

[0053] In this embodiment, the framework of the MOF material with a dodecahedral structure can make the perovskite crystal more stable, thereby further improving the stability of the perovskite absorber layer 3.

[0054] As an embodiment of the present invention, the hole transport layer 4 can be made of NiO. XAny one of CuSCN, CuI, V2O5, and Cu2O.

[0055] As an embodiment of the present invention, the material of electrode 5 can be one of Au, Cu, and C.

[0056] To demonstrate the technical effects achieved by this invention, two groups of perovskite solar cells were tested. The control group's perovskite solar cells used a TiO2 electron transport layer, while the experimental group's perovskite solar cells used an H-TiO2 electron transport layer for the perovskite absorber layer 3. The measured data are shown in Table 1.

[0057] Table 1

[0058] Classification <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm -2 )]]> FF (%) PCE (%) control group 1.10 24 81.5 21.5 experimental group 1.15 25.6 82.7 24.3

[0059] Where Voc is the open-circuit voltage; Jsc is the current density; FF is the fill factor; and PCE is the battery conversion efficiency.

[0060] As can be seen from the experimental data in Table 1 above, compared with traditional perovskite solar cells using a TiO2 electron transport layer, the perovskite solar cell of the present invention using an H-TiO2 electron transport layer can significantly improve the open-circuit voltage, current density, fill factor and cell conversion efficiency of the solar cell, thus greatly improving the cell performance.

[0061] Example 2

[0062] Please refer to Figure 2 The present invention also provides a method for preparing a perovskite solar cell, which is used to prepare the perovskite solar cell of Example 1 above, comprising the following steps:

[0063] Step S1: Prepare H-TiO2 layer 2 on transparent conductive layer 1;

[0064] In this embodiment of the invention, the transparent conductive layer 1 includes a transparent glass substrate and a transparent conductive film disposed sequentially from bottom to top. The transparent glass substrate is used to transmit sunlight, and the transparent conductive film is used for both light transmission and electrical conductivity.

[0065] As an embodiment of the present invention, the transparent conductive film can be any one of ITO film, FTO film, IWO film, IWO film, and ICO film. In practical applications, any one of ITO film, FTO film, IWO film, IWO film, and ICO film can be selected.

[0066] As an embodiment of the present invention, the step of preparing H-TiO2 layer 2 on transparent conductive layer 1 includes:

[0067] A TiO2 film is formed on the transparent conductive layer 1;

[0068] The transparent conductive layer 1, which forms the TiO2 film, is placed in a tube furnace and H2 is introduced into the tube furnace. The furnace is sintered at 400-600℃ for 20-50 minutes to inject H into the TiO2 film to form the HH-TiO2 layer 2.

[0069] In this embodiment, the mass fraction of H2 introduced is 1-10%, specifically a mixture of H2 and inert gas, to avoid the concentration of H2 being too high or too low.

[0070] In this embodiment, by first forming a TiO2 film on the transparent conductive layer 1, and then sintering the TiO2 film with hydrogen gas at 400-600°C for 20-50 minutes, the TiO2 film can be hydrogenated to convert it into H-TiO2 layer 2. The preparation process is very simple and has low cost.

[0071] Furthermore, by injecting hydrogen into TiO2 to form H-TiO2, and using H-TiO2 as an electron transport layer material, the band gap of TiO2 is reduced, thereby improving the conductivity of the electron transport layer of perovskite solar cells and thus improving the efficiency of perovskite solar cells.

[0072] As an embodiment of the present invention, the step of forming a TiO2 film layer on the transparent conductive layer 1 includes:

[0073] Preparation of precursor solution: Add ethanol / water solution dropwise to a mixed solution of ethanol:diethanolamine:tetrabutyl titanate silicon in a volume ratio of 12-15:1-3:3-5 to prepare a precursor solution;

[0074] Preparation of TiO2 film: Immerse transparent conductive layer 1 in precursor solution, and pull transparent conductive layer 1 out of precursor solution at a uniform speed and dry it to form TiO2 film on transparent conductive layer 1.

[0075] In this embodiment, the transparent conductive layer 1 is immersed in the precursor solution using a lifting machine, and then the transparent conductive layer 1 is uniformly lifted out of the precursor solution, thus coating the transparent conductive layer 1 with a uniform precursor solution layer. After the precursor solution layer dries, a TiO2 film layer is formed. The TiO2 film layer is then converted into H-TiO2 layer 2 by sintering with hydrogen gas at 400-600°C for 20-50 minutes.

[0076] In one embodiment of the present invention, the thickness of the H-TiO2 layer 2 is 50–60 nm, which ensures good conductivity while reducing the impact of perovskite solar cells on sunlight absorption.

[0077] As an embodiment of the present invention, when the transparent conductive layer 1 is immersed in the precursor solution, the temperature of the precursor solution is maintained at 25-30°C to avoid oxidation reaction of the precursor solution.

[0078] As an embodiment of the present invention, the transparent conductive layer 1 is pulled out of the precursor solution at a uniform speed of 40-80 mm / min to prevent the precursor solution layer from being too thick or too thin, and to ensure that the thickness of the produced H-TiO2 layer 2 is maintained at 50-60 nm.

[0079] Step S2: Prepare a perovskite absorber layer 3 on the H-TiO2 layer 2;

[0080] In this embodiment of the invention, the perovskite absorber layer 3 can be made of organic or inorganic perovskite, or it can be prepared by reacting perovskite crystals with MOF materials.

[0081] In a preferred embodiment of the present invention, the perovskite absorber layer 3 is prepared by reacting a perovskite crystal with a MOF material doped with metal R atoms. The perovskite crystal has the structural formula PbMAX3, where X is one or more of F, Cl, Br, and I. The MOF material doped with metal R atoms has the structural formula C8H. 10 N4U 1-y R y U and R are one or more of Zn, Ni, Fe, Co, Cu or rare earth metals, and U and R are different from each other, with the mass fraction of R being less than the mass fraction of U.

[0082] In one embodiment of the present invention, the mass fraction of U is 15-40%, and the mass fraction of R is 0.5-10%. The mass fractions of U and R represent percentages of the total mass of the perovskite absorber layer 3. Because the mass fraction of R is 0.5-10% and the mass fraction of U is 15-40%, it ensures that only trace amounts of metal R atoms are doped into the MOF material to regulate its conductivity and band structure, promoting the absorption of visible light, while maintaining low cost. In this embodiment, the preparation method of the perovskite absorber layer 3 includes the following steps:

[0083] Step A, Preparation of MOF material doped with metal atoms: Dissolve metal U salt solution and metal R salt solution in solution C, stir evenly, and then add to solution C containing solution D to obtain a mixed solution. Heat, cool and filter the mixed solution to obtain MOF material doped with metal R atoms; solution C is one or more of methanol, ethanol, isopropanol or acetone, and solution D is one or more of dimethylimidazole, N,N-dimethylformamide, and tris(2-benzimidazolemethyl)amine;

[0084] Wherein, U and R are one or more of Zn, Ni, Fe, Co, Cu, or rare earth metals, and U and R are all different. The metal U salt solution and the metal R salt solution can be determined according to C8H. 10 N4U 1-y R y The selection of metals U and R in the solution allows for the use of inorganic or organic metal salts of different metals, such as C8H. 10 N4U 1-y R y The metals U and R correspond to zinc and nickel, respectively, and the doped metal atom is nickel. The structural formula of the MOF material doped with nickel is C8H. 10 N4Zn 1-y Ni y .

[0085] In a preferred embodiment of the present invention, in step A, the metal U salt solution is zinc nitrate, zinc sulfate, or zinc chloride, and the metal R salt solution is nickel acetylacetone, nickel nitrate, nickel sulfate, or nickel chloride. In this embodiment, C8H 10 N4U 1-y R y The metals U and R correspond to zinc and nickel, respectively, and the doped metal atom is nickel. The structural formula of the MOF material doped with nickel is C8H. 10 N4Zn 1-y Ni y .

[0086] In step A, the perovskite absorber layer 3 consists of a perovskite crystal (PbMAX3) and a MOF material (C8H) doped with metal R atoms. 10 N4U 1-y R y The perovskite crystal is uniformly bonded to the MOF material framework in a one-step reaction. The MOF framework stabilizes the perovskite crystal structure, and the MOF material acts as an electron donor, increasing the conductivity of the entire perovskite absorption layer 3. This facilitates the separation of charge carriers generated by light, thus improving the efficiency of perovskite solar cells. Furthermore, compared to the single-metal U metal-organic framework structure of traditional MOF materials, by doping with a small amount of metal R atoms, the MOF material (C8H) of this invention... 10 N4U 1-y R y In this process, metals U and R form metal-organic framework structures with non-metals, respectively. This allows the conductivity and band structure of the MOF material to be controlled by a relatively small mass fraction of doped metal R atoms, promoting the absorption of visible light. Furthermore, the doped metal R atoms have excellent stability, making the perovskite absorber layer 3 more stable and improving the performance of the perovskite solar cell.

[0087] In step A, the ratios of the metal U salt solution, metal R salt solution, C solution, and D solution can be set according to actual conditions.

[0088] In step A, heating accelerates the dissolution of the metal U salt solution and metal R salt solution with solution C, and also accelerates the coordination of dimethylimidazole, N,N-dimethylformamide, or tris(2-benzimidazolemethyl)amine with the metal U salt solution and metal R salt solution during their reaction, forming a metal U-organic framework material (MOF material) doped with metal atoms R. Filtration serves to remove some undissolved impurities and retain the generated MOF material doped with metal atoms.

[0089] As an embodiment of the present invention, after filtering to obtain the MOF material doped with metal R atoms in step A, the method further includes:

[0090] MOF materials doped with metal R atoms are cleaned using a cleaning solution.

[0091] In this embodiment, the MOF material doped with metal R atoms is cleaned with a cleaning solution to remove residual organic matter inside the pores and on the surface of the MOF material, thereby obtaining a higher purity MOF material.

[0092] In one embodiment of the present invention, the cleaning solution is DMF, methanol, or a mixture of DMF and methanol. Preferably, residual dimethylimidazole, N,N-dimethylformamide, or tris(2-benzimidazolemethyl)amine in the MOF material framework is first cleaned with DMF, and then DMF is removed with methanol. Alternatively, the cleaning solution can also be purified water.

[0093] As an embodiment of the present invention, in step A, the molar ratio of metal U in the metal U salt solution to metal R in the metal R salt solution is 9-95, ensuring that the metal U and metal R in the generated MOF material are within the optimal ratio range, thereby improving the stability and conductivity of the perovskite absorber layer 3.

[0094] As an embodiment of the present invention, in step A, the solution is stirred by ultrasonic stirring for 20-60 minutes until it is clear and uniform, which can make the metal U salt solution and metal R salt solution stirred evenly and the C solution thoroughly stirred.

[0095] In one embodiment of the present invention, in step A, the heating temperature of the mixed solution is 100-150°C.

[0096] In a preferred embodiment of the present invention, the mixed solution is hydrothermally heated in a hydrothermal reactor for 2-8 hours. That is, by transferring the obtained mixed solution to a hydrothermal reactor and hydrothermally heating the mixed solution at 100°C, the heating of the mixed solution is more uniform, which is conducive to the reaction of the mixed solution to form MOF material composed of MOF framework structure with a size of 100-500 μm, and avoids damage to the MOF material.

[0097] Step B, preparing perovskite solution: Add PbX2 and MAX in equal molar ratio to the E solution and stir to prepare PbMAX3 solution. X is one or more of F, Cl, Br, and I. E solution is one or more of DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), NMP (N-methylpyrrolidone), and γ-butyrolactone.

[0098] In this step, PbX2 can be one or more of PbI2, PbBr2, PbCl2, and PbF2, and MAX can be one or more of MAI, MABr, and MACl. Equal molar ratios of PbX2 and MAX are added to solution E, and the solution is stirred for 10-30 minutes to prepare a 45% PbMAX solution.

[0099] In this embodiment of the invention, the order of steps A and B is not limited. That is, the MOF material doped with metal atoms can be prepared first, followed by the perovskite solution, or the perovskite solution can be prepared first, followed by the MOF material doped with metal R atoms. Alternatively, the MOF material doped with metal R atoms and the perovskite solution can be prepared simultaneously.

[0100] Step C, Preparation of perovskite absorber layer 3: The MOF material doped with metal R atoms obtained in step A and the PbMAX3 solution obtained in step B are added to solution E to prepare a precursor solution; the precursor solution is spin-coated onto H-TiO2 layer 2, and an antisolvent is added to H-TiO2 layer 2 during the spin-coating process to obtain a perovskite precursor film, and the perovskite precursor film is annealed to form a perovskite absorber layer 3 composed of perovskite crystals and MOF material doped with metal R atoms.

[0101] In step C, solution E is one or more of DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), NMP (N-methylpyrrolidone), and γ-butyrolactone.

[0102] In step C, the MOF material doped with metal R atoms obtained in step A can be dissolved in solution E first, and then the solution E containing the dissolved MOF material doped with metal R atoms can be mixed and stirred with the PbMAX3 solution obtained in step B to prepare a precursor solution. Alternatively, the MOF material doped with metal R atoms obtained in step A and the PbMAX3 solution obtained in step B can be added to solution E sequentially and mixed and stirred to prepare a precursor solution.

[0103] As an embodiment of the present invention, PbMAX3 and C8H in the precursor solution 10 N4U 1-y R y The molar ratio of PbMAX3 to C8H in the prepared perovskite absorber layer 3 is 0.5–5, so that the PbMAX3 and C8H in the prepared perovskite absorber layer 3 are in a ratio of 0.5–5. 10 N4U 1-y R y The ratio of the number of moles is kept in the range of 0.5 to 5.

[0104] In step C, the specific method of spin-coating the precursor solution onto the H-TiO2 layer 2 is not limited. After the precursor solution is spin-coated onto the H-TiO2 layer 2, an antisolvent is added dropwise to the H-TiO2 layer 2 to reduce the solubility of the perovskite crystals, causing the perovskite crystals and MOF material to precipitate and form a perovskite precursor film. Then, annealing is performed to form a perovskite absorber layer 3 composed of perovskite crystals and MOF material doped with metal R atoms.

[0105] In one embodiment of the present invention, in step C, the annealing temperature is 90-150°C and the annealing time is 5-30 min.

[0106] In one embodiment of the present invention, in step C, the antisolvent is chlorobenzene, ethyl acetate, or a mixture of ethyl acetate and petroleum ether.

[0107] To further illustrate the preparation method of the perovskite absorber layer 3 of the present invention, an actual preparation method of the perovskite absorber layer 3 is given as an example. The preparation method of the perovskite absorber layer 3 specifically includes:

[0108] Preparation of MOF materials doped with metal atoms: 80-1000 mg of nickel acetylacetone and 500-1200 mg of zinc nitrate were dissolved in 20-50 mL of methanol solution. The solution was ultrasonically stirred for 20-60 min until clear. The mixture was then added to 15 mL of methanol solution containing 1300 mg of dimethylimidazole. The solution was then transferred to a hydrothermal reactor and heated at 100-150 °C for 4 h. After cooling and filtering out other impurities, MOF material was obtained. The MOF material was washed sequentially with DMF (N,N-dimethylformamide) and methanol to prepare Ni-doped MOF material (C8H). 10 N4Zn1-x Ni x );

[0109] Preparation of perovskite solution: Add PbX2 and MAX in equal molar ratio to DMF solution and stir to prepare PbMAX3 solution. X can be one or more of F, Cl, Br, I. Stir the solution for 10-30 min to prepare 45 wt% PbMAX solution.

[0110] Preparation of perovskite absorber layer 3: The prepared Ni-doped MOF material was dissolved in a 10-100 mg / mL mixed solution of DMF and DWSO (dimethyl sulfoxide). PbMAX3 solution was then added to the above solution and stirred evenly to prepare a precursor solution. The precursor solution was spin-coated onto H-TiO2 layer 2. During the spin-coating process, 0.15 mL of chlorobenzene was dropped into the center of H-TiO2 layer 2 to obtain a perovskite precursor film. After annealing at 100 °C for 10 min, the perovskite absorber layer 3, composed of perovskite crystals and Ni-doped MOF material, was obtained.

[0111] Step S3: Prepare hole transport layer 4 on perovskite absorber layer 3;

[0112] In this step, the specific method for preparing the hole transport layer 4 on the perovskite absorber layer 3 is not limited, and the preparation process of the hole transport layer 4 of a conventional perovskite solar cell can be used.

[0113] Step S4: Prepare electrode 5 on hole transport layer 4.

[0114] As an embodiment of the present invention, the step of preparing an electrode 5 on the hole transport layer 4 specifically includes: depositing an electrode 5 on the hole transport layer 4 by thermal evaporation.

[0115] The present invention provides a method for fabricating a perovskite solar cell by preparing an H-TiO2 layer as an electron transport layer between a transparent conductive layer and a perovskite absorber layer. The H-TiO2 layer replaces the traditional TiO2 electron transport layer. Compared with the traditional TiO2 electron transport layer, the H-TiO2 formed by H injection can significantly reduce the band gap, thereby improving the conductivity of the electron transport layer and thus improving the efficiency of the perovskite solar cell.

[0116] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A perovskite solar cell, characterized by, include: Transparent conductive layer; An H-TiO2 layer disposed on the transparent conductive layer; A perovskite absorber layer is disposed on the H-TiO2 layer. The perovskite absorber layer is prepared by reacting a perovskite crystal with a MOF material doped with metal R atoms. The perovskite crystal has the structural formula PbMAX3, and X is one or more of F, Cl, Br, and I. The MOF material doped with metal R atoms has the structural formula C8H. 10 N4U 1-y R y U and R are one or more of Zn, Ni, Fe, Co, Cu, or rare earth metals, and U and R are different from each other, wherein the mass fraction of R is less than the mass fraction of U; the PbMAX3 and the C8H 10 N4U 1-y R y The molar ratio of the perovskite crystals is 0.5 to 5; the perovskite crystals are encapsulated inside the framework of the MOF material or attached to the surface of the MOF material framework; the doped metal R atoms are uniformly distributed in the framework of the MOF material, and the doped metal R atoms form chemical bonds with the non-metals of the MOF material. A hole transport layer disposed on the perovskite absorber layer; as well as An electrode disposed on the hole transport layer.

2. The perovskite solar cell according to claim 1, characterized in that, The thickness of the H-TiO2 layer is 50–60 nm.

3. A perovskite solar cell according to claim 1, characterized in that, The mass fraction of U is 15-40%, and the mass fraction of R is 0.5-10%.

4. A method for preparing a perovskite solar cell, characterized by, Includes the following steps: An H-TiO2 layer was prepared on a transparent conductive layer; A perovskite absorber layer is prepared on the H-TiO2 layer. The perovskite absorber layer is obtained by reacting a perovskite crystal with a MOF material doped with metal R atoms. The structural formula of the perovskite crystal is PbMAX3, and X is one or more of F, Cl, Br, and I. The structural formula of the MOF material doped with metal R atoms is C8H. 10 N4U 1-y R y U and R are one or more of Zn, Ni, Fe, Co, Cu, or rare earth metals, and U and R are different from each other. The mass fraction of R is less than the mass fraction of U. The PbMAX3 and C8H 10 N4U 1-y R y The molar ratio of the perovskite crystals is 0.5 to 5; the perovskite crystals are encapsulated inside the framework of the MOF material or attached to the surface of the MOF material framework; the doped metal R atoms are uniformly distributed in the framework of the MOF material, and the doped metal R atoms form chemical bonds with the non-metals of the MOF material. A hole transport layer is prepared on the perovskite absorber layer; Electrodes are fabricated on the hole transport layer.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that, The step of preparing the H-TiO2 layer on the transparent conductive layer includes: A TiO2 film is formed on the transparent conductive layer; The transparent conductive layer forming the TiO2 film is placed in a tube furnace and H2 is introduced into the tube furnace. The furnace is sintered at 400~600℃ for 20~50 minutes to inject H into the TiO2 film to form the H-TiO2 layer.

6. The method of claim 5, wherein the perovskite solar cell is prepared by the steps of: The step of forming a TiO2 film on the transparent conductive layer includes: Preparation of precursor solution: Add ethanol / water solution dropwise to a mixed solution of ethanol:diethanolamine:tetrabutyl titanate silicon in a volume ratio of 12~15:1~3:3~5 to prepare a precursor solution; Preparation of TiO2 film: The transparent conductive layer is immersed in the precursor solution, and the transparent conductive layer is pulled out of the precursor solution at a constant speed and dried to form a TiO2 film on the transparent conductive layer.

7. The method for preparing a perovskite solar cell according to claim 4, characterized in that, The thickness of the H-TiO2 layer is 50–60 nm.

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