A perovskite solar cell and its preparation method

Abstract

The present invention provides a perovskite solar cell and a method for preparing the same. The method comprises the following steps: preparing a porous membrane skeleton, filling the porous membrane skeleton with a perovskite precursor solution, drying a volatile solvent, and forming an interface with a mesoporous electrode layer to obtain a perovskite solar cell; the porous membrane skeleton comprises a conductive substrate, a hole blocking layer, a mesoporous electron transport layer, a mesoporous insulating layer, and a mesoporous electrode layer, which are sequentially arranged; and the perovskite precursor solution comprises at least two perovskites with different band gaps. The method for preparing the perovskite solar cell can reduce the energy level mismatch between the perovskite and the mesoporous electrode layer of the carbon electrode, thereby increasing the open-circuit voltage of the device and thereby improving the device efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a perovskite solar cell and a preparation method thereof. Background Art

[0002] Organic-inorganic hybrid perovskite semiconductor materials are among the fastest-growing materials in the photovoltaic field. With the continuous improvement of the conversion efficiency of perovskite solar cells, the currently certified conversion efficiency has reached 25.8%. Compared with other types of solar cells, perovskite solar cells can be produced using a low-temperature solution method, featuring a simpler fabrication process, a wide range of raw materials, and low production costs. They have great potential to replace single-crystalline silicon solar cells and achieve low-cost photovoltaic power generation.

[0003] Currently, perovskite solar cells can be divided into planar and mesoporous structures. Planar perovskite solar cells are formed by depositing each functional layer layer by layer. From bottom to top, they are a transparent conductive substrate, electron transport layer, perovskite light absorption layer, hole transport layer, and metal electrode. Electrons and holes can be extracted by the electron transport layer material and hole transport layer material, respectively, resulting in low recombination losses and high open-circuit voltage. However, the high cost of the hole transport layer material and metal electrodes in the perovskite solar cell device structure limits further cost reduction. In addition, the thin film is usually prepared by spin coating, which does not allow for large-scale production.

[0004] Perovskite solar cells with mesoporous structures, for example, the printable mesoscopic perovskite solar cell disclosed in Chinese patent document CN103441217B, structurally include a conductive substrate, a hole blocking layer, a nanocrystalline layer, an insulating spacer layer, and a hole collection layer in sequence, wherein the perovskite material runs through the entire three-layer mesoporous membrane, namely the mesoporous nanocrystalline layer, the insulating spacer layer, and the hole collection layer. The device structure is very simple, does not contain expensive metal electrodes and hole transport layer materials, and is very low in cost. Moreover, it adopts screen printing technology and is easy to scale up. Due to the limitation of its mesopores, the printable mesoscopic perovskite solar cell has high stability, which is conducive to commercial production.

[0005] However, the conversion efficiency of printable mesoscopic perovskite solar cells is lower than that of planar perovskite solar cells. The main reason for the reduced conversion efficiency is the loss of open-circuit voltage. Because printable mesoscopic perovskite solar cells do not contain hole transport layer materials, there is an energy level mismatch between the perovskite and the carbon electrode. Electrons not extracted by titanium oxide diffuse to the carbon electrode and recombine with holes on the carbon electrode, resulting in a decrease in open-circuit voltage. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a perovskite solar cell and a preparation method thereof, so as to solve the technical problem in the prior art that there is an energy level mismatch between the perovskite and the carbon electrode of the perovskite solar cell, and the carbon electrode extracts electrons, resulting in reduced conversion efficiency.

[0007] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0008] A method for preparing a perovskite solar cell comprises the following steps:

[0009] A porous membrane skeleton is filled with a perovskite precursor solution, and then the volatile solvent is dried and an interface is formed on the mesoporous electrode layer to obtain a perovskite solar cell;

[0010] The porous membrane skeleton comprises a conductive substrate, a hole blocking layer, a mesoporous electron transport layer, a mesoporous insulating layer, and a mesoporous electrode layer arranged in sequence;

[0011] The perovskite precursor solution includes at least two perovskites with different band gaps.

[0012] Preferably, the perovskite precursor solution forms gradient perovskite in the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer.

[0013] Preferably, the perovskite precursor solution comprises A 1-x B x ; Wherein, 0<x<1, A is a narrow bandgap perovskite; B is a wide bandgap perovskite.

[0014] Preferably, said A is MAPb 1-a Sn a I3、FAPb 1-a Sn a One or more of I3; wherein, 0≤a≤1, MA is methylamine, and FA is formamidine.

[0015] Preferably, the B is CsPb(I b Br c Cl 1-b-c )3、M2Pb(I b Br c Cl 1-b-c )4; wherein, 0≤b+c≤1, b≥0, c≥0, and M is an organic amine having more than 2 carbon atoms.

[0016] More preferably, the organic amine is one of phenylethylamine, benzylamine, butylamine and propylamine.

[0017] Preferably, the perovskite precursor solution further includes a solvent and additives.

[0018] Preferably, the solvent is one or more of DMF and DMSO; wherein DMF refers to N,N-dimethylformamide; and DMSO refers to dimethyl sulfoxide.

[0019] Optionally, the additive is MAC1, wherein MAC1 refers to methylamine chloride.

[0020] Preferably, the conductive substrate is FTO; wherein FTO refers to fluorine-doped tin oxide conductive glass.

[0021] Optionally, the hole blocking layer is titanium dioxide;

[0022] Optionally, the mesoporous electron transport layer is one of titanium dioxide, tin oxide, and zinc oxide;

[0023] Optionally, the mesoporous insulating layer is one of zirconium dioxide and aluminum oxide;

[0024] Optionally, the mesoporous electrode layer is a carbon electrode.

[0025] Preferably, the carbon electrode is one or more of graphite sheets, carbon black, carbon nanotubes, and graphene.

[0026] Further preferably, the porous membrane skeleton is prepared by the following method:

[0027] The conductive substrate is separated into positive and negative electrodes by laser etching, the conductive substrate is heated to 450°C, and an isopropyl alcohol solution of di(acetylacetonato)titanate is sprayed onto the conductive substrate using a carrier gas to form a dense titanium dioxide as a hole blocking layer; then, the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer are sequentially printed on the cavity blocking layer by screen printing, and the layers are sintered at 400°C for 1 hour to obtain the porous membrane skeleton.

[0028] Preferably, an interface is formed in the mesoporous electrode layer through an ion exchange reaction or a phase change process; the interface is one or more of a formamidine-based non-perovskite phase, a cesium-based non-perovskite phase, a low-dimensional perovskite, a bromine-based perovskite, a chloride-based perovskite, lead iodide, and lead bromide.

[0029] Further preferably, the method for preparing the perovskite solar cell specifically comprises the following steps:

[0030] A porous membrane skeleton is taken and filled with a perovskite precursor solution. Then, the volatile solvent is dried at 50-110°C and placed at a temperature of 20-25°C and a relative humidity of 50-70% RH for more than 24 hours to form an interface with the mesoporous electrode layer to obtain a perovskite solar cell.

[0031] Alternatively, the method for preparing the perovskite solar cell specifically comprises the following steps:

[0032] A porous membrane skeleton is taken and filled with a perovskite precursor solution. Then, the volatile solvent is dried at 50-110°C and an ion exchange reaction is caused to occur, thereby forming an interface in the mesoporous electrode layer to obtain a perovskite solar cell.

[0033] The ion exchange reaction is performed by post-treatment with an isopropanol solution of phenylethylamine, wherein the concentration of the phenylethylamine is 10-50 mg / ml; and the ion exchange reaction occurs by immersing or drop-coating the porous membrane skeleton with the isopropanol solution of phenylethylamine.

[0034] The present invention also provides a perovskite solar cell obtained by the preparation method of the perovskite solar cell.

[0035] The above solution of the present invention includes at least the following beneficial effects:

[0036] The present invention discloses a method for preparing a perovskite solar cell, comprising the following steps: preparing a porous membrane skeleton, filling it with a perovskite precursor solution, drying a volatile solvent, and forming an interface with a mesoporous electrode layer to obtain a perovskite solar cell; the porous membrane skeleton comprises a conductive substrate, a hole blocking layer, a mesoporous electron transport layer, a mesoporous insulating layer, and a mesoporous electrode layer, which are sequentially arranged; and the perovskite precursor solution comprises at least two perovskites with different band gaps. In the method for preparing a perovskite solar cell, the porous membrane skeleton can be prepared by screen printing, which facilitates large-scale preparation. Furthermore, an inexpensive carbon electrode can be used as the mesoporous electrode layer, eliminating the need for expensive hole transport layer materials, thereby facilitating inexpensive photovoltaic power generation. More importantly, the perovskite precursor solution includes at least two perovskites with different band gaps. By designing an alternating wide and narrow energy band structure, a gradient distribution structure is formed in the porous membrane skeleton from the mesoporous electron transport layer to the mesoporous electrode layer, in which the wide band gap material increases successively, which is beneficial to the transport of holes. In addition, an interface is formed in the mesoporous electrode layer. Since a wide band gap interface layer material is constructed between the perovskite and the mesoporous electrode layer, the mismatch between the perovskite and the mesoporous electrode layer of the carbon electrode can be reduced, the open circuit voltage of the device can be increased, and thus the device efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the partial structure of the perovskite solar cell according to the present invention;

[0038] Figure 2 yes Figure 1 Schematic diagram of the perovskite band structure in the middle S region.

[0039] Among them, 1. Mesoporous electrode layer; 2. Mesoporous insulating layer; 3. Mesoporous electron transport layer. DETAILED DESCRIPTION

[0040] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] Example 1

[0042] The method for preparing a perovskite solar cell of this embodiment comprises the following steps:

[0043] A porous membrane skeleton is taken and filled with a perovskite precursor solution. Then, the volatile solvent is dried and an interface is formed in the mesoporous electrode layer to obtain a perovskite solar cell; the perovskite precursor solution forms a gradient perovskite in the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer.

[0044] Wherein, the porous membrane skeleton includes a conductive substrate, a hole blocking layer, a mesoporous electron transport layer, a mesoporous insulating layer, and a mesoporous electrode layer arranged in sequence; in this embodiment, the conductive substrate is FTO; the hole blocking layer is titanium dioxide; the mesoporous electron transport layer is titanium dioxide; the mesoporous insulating layer is zirconium dioxide; and the mesoporous electrode layer is a carbon electrode. The carbon electrode can be one or more of graphite sheets, carbon black, carbon nanotubes, and graphene. In this embodiment, the carbon electrodes are graphite sheets and carbon black. That is, the porous membrane skeleton is FTO / c-TiO2 / m-TiO2 / m-ZrO2 / mC. As Figure 1 FIG. 1 is a schematic diagram of a partial structure of a perovskite solar cell according to this embodiment, wherein the perovskite precursor solution forms a gradient perovskite in the mesoporous electron transport layer 3 , the mesoporous insulating layer 2 , and the mesoporous electrode layer 1 . Figure 1 The perovskite band structure in the S region is as follows Figure 2 shown.

[0045] The porous membrane skeleton is prepared by the following method:

[0046] The conductive substrate is laser etched to separate the positive and negative electrodes, the conductive substrate is heated to 450°C, and an isopropyl alcohol solution of di(acetylacetonato)titanate is sprayed onto the conductive substrate using a carrier gas to form a dense titanium dioxide as a hole blocking layer; then, the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer are sequentially printed on the cavity blocking layer by screen printing, and the layers are sintered at 400°C for 2 hours to obtain the porous membrane skeleton.

[0047] In this embodiment, the perovskite precursor solution includes at least two perovskites with different band gaps, and also includes a solvent and an additive. As a specific implementation of this embodiment, the perovskite precursor solution includes A 1-x B x ; Wherein, x = 0.05, A is a narrow bandgap perovskite; B is a wide bandgap perovskite. A is FAPb 1-a Sn a I3; wherein a=0, FA is formamidine; i.e. FAPbI3. The B is CsPb(I b Br c Cl 1-b-c )3; wherein, c=1, b=0; i.e. CsPbBr3. 1-x B x for (FAPbI3) 0.95 (CsPbBr3) 0.05 The solvent is a mixture of DMF and DMSO; the additive is MACl.

[0048] The preparation method of the perovskite precursor solution is as follows:

[0049] (1) Take FAI and PbI2 and use acetonitrile as the reaction solvent to react and generate FAPbI3.

[0050] In this example, 7.66 g of FAPbI was dissolved in 150 mL of acetonitrile at room temperature with continuous stirring. Then, 15.67 g of PbI2 (low-purity 95%; PbI2 / FAI = 1 / 1.3) was slowly added. Then, 50 mL of acetonitrile was added and stirred for 24 hours. The precipitate gradually changed from brown to bright yellow. The precipitate was washed several times with acetonitrile and dried under reduced pressure by rotary evaporation to obtain yellow FAPbI3 nanocrystals.

[0051] (2) PbBr2 is dissolved in hydrobromic acid, and CsBr is added thereto to react and generate CsPbBr3.

[0052] In this example, 7.35 g of PbBr2 was dissolved in 16 mL of hydrobromic acid, to which a CsBr solution (prepared by dissolving 4.26 g of CsBr in 10 mL of deionized water) was added dropwise. This reaction produced an orange-yellow precipitate. The precipitate was filtered, washed twice with ethanol, and then dried in a vacuum oven at 60°C for 12 hours to obtain CsPbBr3 nanocrystals.

[0053] (3) According to 1 mol / L (FAPbI3) 0.95 (CsPbBr3) 0.05The ratio of FAPbI3 in step (1) and CsPbBr3 in step (2) are taken, dissolved in the solvent, and then MACl with a mass concentration of 30-40% is added thereto to obtain.

[0054] In this embodiment, the method for preparing the perovskite solar cell specifically includes the following steps:

[0055] A porous membrane skeleton is taken and filled with a perovskite precursor solution. Then, the volatile solvent is dried at 80°C and placed at a temperature of 25°C and a relative humidity of 60% RH for more than 24 hours to form an interface with the mesoporous electrode layer to obtain a perovskite solar cell.

[0056] It should be noted that an interface is formed in the mesoporous electrode layer through a phase transition process; the interface is a formamidine-based non-perovskite phase. For the purposes of the present invention, it can also be one or more of a cesium-based non-perovskite phase, a low-dimensional perovskite, a bromine-based perovskite, a chloride-based perovskite, lead iodide, and lead bromide.

[0057] In this embodiment, due to the colloidal properties of the perovskite precursor solution, the multi-component precursor exhibits colloids of varying sizes. Since the solubility of the FAPbI3 component is greater than that of CsPbBr3, the degree of ionization of FAPbI3 in the perovskite precursor solution is higher than that of CsPbBr3. Consequently, the micelle diameter of the CsPbBr3 portion is larger than that of FAPbI3. The carbon electrode in the mesoporous electrode layer of the porous membrane skeleton has a micron-scale pore size, while the mesoporous zirconium dioxide and mesoporous titanium dioxide have pore sizes less than 50 nm. Therefore, the perovskite precursor exhibits a distribution of colloid particles of varying sizes within the three-layer porous membrane. The larger CsPbBr3 colloid particles are primarily present in the porous carbon electrode, while the smaller FAPbI3 colloid particles are primarily present in the m-TiO2 / m-ZrO2 of the three-layer porous membrane, forming a perovskite structure with a gradient distribution of wide and narrow band gaps. Next, a phase transition process is used to convert the small amount of narrow-bandgap perovskite on the carbon electrode into a wide-bandgap material to obtain a wide-bandgap interface layer. Specifically, the porous membrane skeleton is filled with formamidine perovskite, which is typically very susceptible to external environmental influences such as humidity and pressure at room temperature, and then transforms from a black formamidine perovskite phase to a yellow non-perovskite phase. The yellow non-perovskite phase has a wide bandgap and is a good match for the black formamidine phase. It can block electrons not extracted by titanium dioxide from diffusing to the carbon electrode, thereby increasing the open-circuit voltage of the device and improving the conversion efficiency of the perovskite solar cell.

[0058] Example 2

[0059] The method for preparing a perovskite solar cell of this embodiment comprises the following steps:

[0060] A porous membrane skeleton is taken and filled with a perovskite precursor solution. Then, the volatile solvent is dried and an interface is formed in the mesoporous electrode layer to obtain a perovskite solar cell; the perovskite precursor solution forms a gradient perovskite in the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer.

[0061] The porous membrane skeleton comprises a conductive substrate, a hole-blocking layer, a mesoporous electron transport layer, a mesoporous insulating layer, and a mesoporous electrode layer, arranged in this order. In this embodiment, the conductive substrate is FTO; the hole-blocking layer is titanium dioxide; the mesoporous electron transport layer is titanium dioxide; the mesoporous insulating layer is zirconium dioxide; and the mesoporous electrode layer is a carbon electrode. The carbon electrode can be one or more of graphite flakes, carbon black, carbon nanotubes, and graphene. In this embodiment, the carbon electrodes are graphite flakes and carbon black. Specifically, the porous membrane skeleton is FTO / c-TiO2 / m-TiO2 / m-ZrO2 / mC.

[0062] The porous membrane skeleton is prepared by the following method:

[0063] The conductive substrate is laser etched to separate the positive and negative electrodes, the conductive substrate is heated to 450°C, and an isopropyl alcohol solution of di(acetylacetonato)titanate is sprayed onto the conductive substrate using a carrier gas to form a dense titanium dioxide as a hole blocking layer; then, the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer are sequentially printed on the cavity blocking layer by screen printing, and the layers are sintered at 400°C for 2 hours to obtain the porous membrane skeleton.

[0064] In this embodiment, the perovskite precursor solution includes at least two perovskites with different band gaps, and also includes a solvent and an additive. As a specific implementation of this embodiment, the perovskite precursor solution includes A 1-x B x ; Wherein, x = 0.05, A is a narrow bandgap perovskite; B is a wide bandgap perovskite. A is FAPb 1-a Sn a I3; wherein a=0, FA is formamidine; i.e. FAPbI3. The B is CsPb(I b Br c Cl 1-b-c )3; wherein, c=1, b=0; i.e. CsPbBr3. 1-x B x for (FAPbI3) 0.95 (CsPbBr3) 0.05 The solvent is a mixture of DMF and DMSO in a weight ratio of 1:1; and the additive is MACl.

[0065] The preparation method of the perovskite precursor solution is the same as that in Example 1.

[0066] In this embodiment, the method for preparing the perovskite solar cell specifically includes the following steps:

[0067] A porous membrane skeleton is taken and filled with a perovskite precursor solution. Then, the volatile solvent is dried at 50°C and an ion exchange reaction is caused to occur, thereby forming an interface in the mesoporous electrode layer to obtain a perovskite solar cell.

[0068] The ion exchange reaction is performed by post-treatment with an isopropanol solution of phenethylamine, wherein the concentration of the phenethylamine is any value within the range of 10-50 mg / ml. In this embodiment, the concentration of the phenethylamine is 30 mg / ml. The ion exchange reaction occurs by immersing or dripping the porous membrane skeleton with the isopropanol solution of phenethylamine.

[0069] It should be noted that an interface is formed in the mesoporous electrode layer by an ion exchange reaction; the interface is one or more of a formamidine-based non-perovskite phase, a cesium-based non-perovskite phase, a low-dimensional perovskite, a bromine-based perovskite, a chloride-based perovskite, lead iodide, and lead bromide.

[0070] In this embodiment, due to the colloidal properties of the perovskite precursor solution, the multi-component precursor exhibits colloids of varying sizes. Since the solubility of the FAPbI3 component is greater than that of CsPbBr3, the degree of ionization of FAPbI3 in the perovskite precursor solution is higher than that of CsPbBr3. Consequently, the micelle diameter of the CsPbBr3 portion is larger than that of FAPbI3. The carbon electrode in the mesoporous electrode layer of the porous membrane skeleton has a micron-scale pore size, while the mesoporous zirconium dioxide and mesoporous titanium dioxide have pore sizes less than 50 nm. Therefore, the perovskite precursor exhibits a distribution of colloid particles of varying sizes within the three-layer porous membrane. The larger CsPbBr3 colloid particles are primarily present in the porous carbon electrode, while the smaller FAPbI3 colloid particles are primarily present in the m-TiO2 / m-ZrO2 of the three-layer porous membrane, forming a perovskite structure with a gradient distribution of wide and narrow band gaps. Next, an ion exchange reaction is used to convert a small amount of narrow-bandgap perovskite on the carbon electrode into a wide-bandgap material, thereby obtaining a wide-bandgap interface layer. When post-treated with an isopropyl alcohol solution of phenylethylamine, the organic components in the perovskite dissolve in the isopropyl alcohol solution, while the inorganic framework is insoluble in isopropyl alcohol. The phenylethylamine post-treatment solution then undergoes an intercalation reaction with the inorganic perovskite framework on the carbon electrode, forming a yellow, wide-bandgap, low-dimensional perovskite. This reduces non-radiative recombination between the perovskite and the carbon electrode, improving the device's open-circuit voltage and conversion efficiency.

[0071] Example 3

[0072] This embodiment adopts the same preparation method of the perovskite solar cell as that of Example 1, with the only difference being that this embodiment specifically includes the following steps: taking a porous membrane skeleton, filling it with a perovskite precursor solution, then drying the volatile solvent at 110°C, and then placing it at a temperature of 20°C and a relative humidity of 70% RH for more than 24 hours to form an interface in the mesoporous electrode layer to obtain a perovskite solar cell.

[0073] Instead of the perovskite precursor solution in Example 1, in this embodiment, the perovskite precursor solution includes A 1-x B x ; Wherein, x = 0.95, A is a narrow bandgap perovskite; B is a wide bandgap perovskite. A is FAPb 1-a Sn a I3; where a = 0.03, FA is formamidine; ie MAPb 0.97 Sn 0.03 I3. The B is M2Pb(I b Br c Cl 1-b-c )4; wherein c=1, b=0; i.e. M2PbBr4. M is propylamine. 1-x B x (FAPb 0.97 Sn 0.03 I3) 0.95 (M2PbBr4) 0.05 .

[0074] Example 4

[0075] This embodiment uses the same method for preparing a perovskite solar cell as that of Example 2, with the only difference being that this embodiment specifically includes the following steps: taking a porous membrane skeleton, filling it with a perovskite precursor solution, then drying a volatile solvent at 110°C, and then causing an ion exchange reaction to form an interface at the mesoporous electrode layer to obtain a perovskite solar cell. The ion exchange reaction is performed by post-treating the porous membrane skeleton with an isopropanol solution of phenylethylamine, wherein the concentration of the phenylethylamine is 50 mg / ml; the ion exchange reaction is performed by immersing or drop-coating the porous membrane skeleton with the isopropanol solution of phenylethylamine.

[0076] Instead of the perovskite precursor solution in Example 1, in this embodiment, the perovskite precursor solution includes A 1-x B x ; Wherein, x=0.1, A is a narrow bandgap perovskite; B is a wide bandgap perovskite. A is MAPb 1-a Sn a I3; where a = 0.03, FA is methylamine; i.e. FAPb 0.97 Sn 0.03I3. The B is M2Pb(I b Br c Cl 1-b-c )4; wherein c=1, b=0; i.e. M2PbBr4. M is propylamine. 1-x B x (Pb 0.97 Sn 0.03 ) 0.9 (M2PbBr4) 0.1 .

[0077] Comparative Example 1

[0078] This comparative example uses the same raw materials and methods as Example 1 to prepare perovskite solar cells, with the only difference being that the step of forming an interface in the mesoporous electrode layer is not included, that is, the following step is not included: placing the porous membrane skeleton at 25°C and a relative humidity of 60% RH for more than 24 hours to form an interface in the mesoporous electrode layer.

[0079] Comparative Example 2

[0080] This comparative example uses the same raw materials and methods as Example 2 to prepare a perovskite solar cell, with the only difference being that the step of forming an interface in the mesoporous electrode layer is not included, that is, the following step of causing the porous membrane skeleton to undergo ion exchange reaction to form an interface in the mesoporous electrode layer is not included.

[0081] Effect comparison ratio

[0082] To verify the technical effect of the method for preparing a perovskite solar cell according to the present invention, the following experiments were conducted:

[0083] The perovskite solar cells prepared in Examples 1-2 and Comparative Examples 1-2 were tested for performance under standard sunlight of AM1.5G, including short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency.

[0084] After experimentation, the results are as follows:

[0085]

[0086] Comparison of Examples 1-4 with Comparative Examples 1-2 shows that Comparative Examples 1-2, which do not form an interface within the mesoporous electrode layer, exhibit significantly lower open-circuit voltage and photoelectric conversion efficiency than Examples 1-4. The method for preparing perovskite solar cells according to the present invention achieves a higher open-circuit voltage and improves the conversion efficiency of perovskite solar cells, particularly Example 2, which achieves a photoelectric conversion efficiency of 17.51%.

[0087] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The steps include: A porous membrane skeleton is taken, a perovskite precursor solution is filled into it, and then a volatile solvent is dried and an interface is formed at the mesoporous electrode layer to obtain a perovskite solar cell; wherein the volatile solvent is dried at 80°C and then placed at a temperature of 25°C and a relative humidity of 60% RH for more than 24 hours to form an interface at the mesoporous electrode layer to obtain a perovskite solar cell; or, the volatile solvent is dried at 50°C and then an ion exchange reaction is caused to form an interface at the mesoporous electrode layer to obtain a perovskite solar cell; or, the volatile solvent is dried at 110°C and then placed at a temperature of 20°C and a relative humidity of 70% RH for more than 24 hours to form an interface at the mesoporous electrode layer to obtain a perovskite solar cell; or, the volatile solvent is dried at 110°C and then an ion exchange reaction is caused to form an interface at the mesoporous electrode layer to obtain a perovskite solar cell; wherein the ion exchange reaction is caused by immersing or drop-coating the porous membrane skeleton with an isopropanol solution of phenylethylamine; The porous membrane skeleton comprises a conductive substrate, a hole blocking layer, a mesoporous electron transport layer, a mesoporous insulating layer, and a mesoporous electrode layer arranged in sequence; The perovskite precursor solution forms a gradient perovskite in the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer; Wherein, the porous membrane skeleton is prepared by the following method: The conductive substrate is laser etched to separate the positive and negative electrodes, the conductive substrate is heated to 450° C., and an isopropyl alcohol solution of di(acetylacetonato)titanate is sprayed onto the conductive substrate using a carrier gas to form titanium dioxide as a hole blocking layer; the mesoporous electron transport layer, the mesoporous insulating layer, and the mesoporous electrode layer are sequentially printed on the hole blocking layer by screen printing, and the layers are sintered at 400° C. for 2 hours to obtain the porous membrane skeleton; Wherein, the preparation method of the perovskite precursor solution is as follows: (1) FAI and PbI2 are reacted in acetonitrile as a reaction solvent to produce FAPbI3; wherein, FAI is dissolved in acetonitrile and stirred continuously at room temperature, PbI2 of low purity 95% is added, PbI2 / FAI = 1 / 1.3, and acetonitrile is added, and stirred continuously for 24 hours. The precipitate is washed with acetonitrile several times and dried under reduced pressure by rotary evaporation to obtain yellow FAPbI3 nanocrystals; (2) PbBr2 is dissolved in hydrobromic acid, and CsBr is added thereto to react and generate CsPbBr3; wherein, PbBr2 is dissolved in hydrobromic acid, and a CsBr solution is added thereto dropwise, wherein the CsBr solution is obtained by dissolving CsBr in deionized water, and the reaction generates an orange-yellow precipitate; the precipitate is filtered, washed twice with ethanol, and dried in a vacuum drying oven at 60°C for 12 hours to obtain CsPbBr3 nanocrystals; (3) Take the FAPbI3 in step (1) and the CsPbBr3 in step (2), dissolve them in a solvent, and then add 30-40% MACl to obtain; The perovskite precursor solution includes at least two perovskites with different band gaps; Wherein, the perovskite precursor solution includes A 1-x B x ; Wherein, 0<x<1, A is a narrow bandgap perovskite; B is a wide bandgap perovskite.

2. The method for preparing a perovskite solar cell according to claim 1, wherein: The perovskite precursor solution also includes a solvent and additives.

3. The method for preparing a perovskite solar cell according to claim 2, wherein: The solvent is one or more of DMF and DMSO; The additive is MACl.

4. The method for preparing a perovskite solar cell according to claim 1, wherein: The conductive substrate is FTO; The hole blocking layer is titanium dioxide; The mesoporous electron transport layer is one of titanium dioxide, tin oxide and zinc oxide; The mesoporous insulating layer is one of zirconium dioxide and aluminum oxide; The mesoporous electrode layer is a carbon electrode.

5. The method for preparing a perovskite solar cell according to claim 4, wherein: The carbon electrode is one or more of graphite sheets, carbon black, carbon nanotubes, and graphene.

6. The method for preparing a perovskite solar cell according to claim 1, wherein: An interface is formed in the mesoporous electrode layer through an ion exchange reaction or a phase change process; the interface is one or more of a formamidine-based non-perovskite phase, a cesium-based non-perovskite phase, a low-dimensional perovskite, a bromine-based perovskite, a chloride-based perovskite, lead iodide, and lead bromide.

7. A perovskite solar cell obtained by the preparation method of a perovskite solar cell according to any one of claims 1 to 6.

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