Preparation method of wide-band-gap perovskite solar cell

Abstract

The invention belongs to the technical field of laminated photovoltaic cells, and particularly provides a preparation method of a wide-band-gap perovskite solar cell, which is used for solving the problems that in the prior art, a wide-band-gap perovskite light absorption layer has too many defects and is poor in phase separation and crystallization quality, so that carrier transmission is hindered, and the service life of the wide-band-gap perovskite solar cell is prolonged. And the open-circuit voltage and the efficiency of the perovskite solar cell are reduced. Methylamine hydrochloride (MACL) and phenethyl ammonium acetate (PEAAc) are introduced as precursor additives in the preparation process of the perovskite light absorption layer, the MACL can significantly inhibit degradation of a perovskite precursor solution, and the preparation of a high-quality perovskite thin film with oriented growth and excellent crystallization is facilitated; nH2 of PEAAc can provide Pb < 2 + > electrons to passivate halogen vacancies; moreover, through the synergistic effect of the MACL and the PEAAc, a perovskite thin film with better crystallization quality and fewer defects can be obtained, so that the open-circuit voltage and the photoelectric conversion efficiency of a perovskite solar cell device are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laminated photovoltaic cells, relates to a preparation process of a perovskite solar cell, and specifically provides a preparation method of a wide bandgap perovskite solar cell. Background Art

[0002] As the third generation of solar cells in the field of photovoltaic cell technology, organic-inorganic hybrid perovskite solar cells (PSCs) are considered to be one of the most promising photovoltaic technologies at present due to their high efficiency and low-cost solution processability. In recent years, the best power conversion efficiency (PCE) of single-junction PSCs has been improved to 26%. On this basis, in order to further improve the performance of perovskite solar cells, solve the problem of the efficiency limit of single-junction perovskites, and achieve cheap manufacturing, stacked perovskite solar cells have emerged. All-perovskite tandem solar cells include a lead-based hybrid bromide-iodide wide-bandgap perovskite top cell and a hybrid lead and tin narrow-bandgap perovskite bottom cell. Most of the functional layers can be manufactured by low-temperature solution processing technology and are compatible with flexible substrates, showing great potential for developing the next generation of economical and efficient photovoltaic technology.

[0003] However, the open circuit voltage (V OC ) is still below its theoretical limit, which may be due to the large voltage loss of the subcell, especially the wide bandgap subcell containing a large amount of bromine (Br) that is prone to phase segregation. The mixture of iodine (I) and bromine usually suffers from severe phase segregation and poor energy level alignment in wide bandgap perovskite solar cells (WBG), resulting in a large open circuit voltage (V OC ) loss, which in turn leads to reduced efficiency and the inability to efficiently convert solar energy into electrical energy. This problem needs to be solved urgently. Summary of the invention

[0004] The present invention provides a method for preparing a wide bandgap perovskite solar cell, which is used to solve the problem in the prior art that the wide bandgap perovskite light-absorbing layer has too many defects, phase separation, and poor crystallization quality, which hinders carrier transmission, thereby causing the open circuit voltage and efficiency of the perovskite solar cell to decrease. The present invention introduces methylamine hydrochloride (MACL) and phenethylammonium acetate (PEAAc) as additives in the preparation process of the perovskite light-absorbing layer of the wide bandgap perovskite solar cell, wherein methylamine hydrochloride (MACL) can significantly inhibit the degradation of the perovskite precursor solution, and when used as a precursor additive, it is beneficial to prepare a high-quality perovskite film with oriented growth and excellent crystallization; NH2 in phenethylammonium acetate (PEAAc) can provide Pb 2+electrons, passivating halogen vacancies; at the same time, the negatively charged COO- group can interact with the undercoordinated formamidinium ion (FA+) and lead ion (Pb2+) through hydrogen bonds and coordination bonds, respectively; and PEAAc enhances the uniform distribution of halide phases and reduces the defect density in perovskite films by regulating the crystallization rate of mixed halides; in addition, the synergistic effect of MACL and PEAAc can obtain perovskite films with better crystallization quality and fewer defects, thereby effectively improving the open circuit voltage and photoelectric conversion efficiency of perovskite solar cell devices.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for preparing a wide bandgap perovskite solar cell, characterized in that it comprises the following steps:

[0007] Step 1, cleaning the transparent conductive glass substrate;

[0008] Step 2: depositing a hole transport layer on the surface of a transparent conductive glass substrate by a magnetron sputtering process;

[0009] Step 3, preparing a 2PACz ethanol solution, spin coating it on the surface of the hole transport layer, and then annealing it to form a 2PACz layer;

[0010] Step 4, preparing a wide bandgap perovskite modified precursor solution, including: an initial perovskite precursor solution and MACl, wherein the molar concentration of MACl is 10% to 30% of the molar concentration of the initial perovskite precursor solution;

[0011] Step 5, spin coating the wide bandgap perovskite modified precursor solution on the surface of the 2PACz layer and then annealing to form a perovskite light absorbing layer;

[0012] Step 6: Using a vacuum thermal evaporation process to deposit an electron transport layer on the surface of the perovskite light absorbing layer;

[0013] Step 7: Use a vacuum thermal evaporation process to deposit an electrode layer on the surface of the electron transport layer to obtain a wide bandgap perovskite cell.

[0014] Furthermore, in step 1, the cleaning process is: using acetone to ultrasonically clean the transparent conductive glass substrate for 10 minutes to 20 minutes, then using ethanol to ultrasonically clean the transparent conductive glass substrate for 10 minutes to 20 minutes, and drying it in an oven for later use.

[0015] Furthermore, in step 2, the hole transport layer is a nickel oxide layer.

[0016] Furthermore, in step 3, the concentration of the 2PACz ethanol solution is 1 mg / mL to 3 mg / mL, and the spin coating process is: spin coating the 2PACz ethanol solution on the surface of the hole transport layer at a speed of 2000 rpm to 5000 rpm, and the spin coating time is 30s to 40s; the annealing process is: annealing at a temperature of 100°C to 150°C for 10min to 20min.

[0017] Furthermore, in step 4, the wide bandgap perovskite modified precursor solution further includes: PEAAc, and the molar concentration of PEAAc is 0.2% to 0.8% of the molar concentration of the initial perovskite precursor solution.

[0018] Furthermore, in step 4, the molar ratio of CsI, MABr, FAI, PbI2 and PbBr2 in the initial perovskite precursor solution is 0.05:0.43:0.52:0.57:0.47.

[0019] Further, in step 5, the spin coating process is as follows: first, the precursor solution of the perovskite light absorbing layer is spin coated at an acceleration of 800 rpm / s to 1500 rpm / s for 3s to 8s; then, the spin coating is performed at a rotation speed of 4000 rpm to 6000 rpm for 40s, and 0.1 mL to 0.2 mL of chlorobenzene antisolvent is dripped onto the surface 5s to 15s after the start of the current spin coating;

[0020] The annealing process is: annealing at a temperature of 100°C to 150°C for 30min to 60min.

[0021] Further, in step 6, the electron transport layer is composed of lithium fluoride (LiF), carbon 60 layer (C 60 ), 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline layer (BCP) are stacked in sequence.

[0022] Furthermore, in step 7, the metal used for the electrode layer is silver (Ag) or gold (Au).

[0023] Based on the above technical solution, the beneficial effects of the present invention are:

[0024] 1. The present invention provides a method for preparing a wide bandgap perovskite solar cell. By adding MACl to a wide bandgap perovskite precursor solution, the initial nucleus formation with a (100) preferred orientation can be effectively induced, and adjacent seed crystals can be connected, thereby limiting the inclination of grains and improving the crystallization quality of the perovskite layer. In addition, a PEAAc solution is added to the perovskite precursor solution, and the negatively charged COO- group can interact with under-coordinated formamidinium ions (FA+) and lead ions (Pb2+) through hydrogen bonds and coordination bonds, respectively, which can passivate halogen vacancies, enhance the uniform distribution of halide phases and reduce the defect density in the perovskite film, thereby forming a denser and smoother perovskite film, and finally effectively improving the overall performance of the wide bandgap perovskite solar cell.

[0025] 2. The present invention provides a method for preparing a wide-bandgap perovskite solar cell, which can improve the yield of the wide-bandgap perovskite cell, obtain a high open-circuit voltage and better cell conversion efficiency, and is more conducive to the stacking application and long-term use of the cell.

[0026] 3. The present invention provides a method for preparing a wide-bandgap perovskite solar cell. Based on the moisture resistance of the polymer and the good transfer of interface charges, the long-term stability of the wide-bandgap perovskite solar cell is significantly improved, thereby solving the problem of poor stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the inverted perovskite solar cell prepared in the present invention.

[0028] Figure 2 Schematic diagram of the spin coating annealing process of the hole transport layer and the perovskite light absorbing layer in the inverted perovskite solar cell of the present invention.

[0029] Figure 3 X-ray diffraction (XRD) patterns of the wide bandgap perovskite films prepared in Examples 1 to 3 of the present invention and Comparative Example 1.

[0030] Figure 4 The external quantum efficiency (EQE) spectra of the wide bandgap perovskite solar cells prepared in Examples 1 to 3 of the present invention and Comparative Example 1 are shown.

[0031] Figure 5 X-ray diffraction (XRD) patterns of the wide bandgap perovskite films prepared in Example 2, Example 4, Example 5 and Comparative Example 1 of the present invention.

[0032] Figure 6 Time-resolved photoluminescence (TRPL) spectra of the wide-bandgap perovskite films prepared in Examples 4 to 5 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] The present invention provides a method for preparing a wide bandgap perovskite solar cell, wherein the wide bandgap perovskite solar cell is Figure 1 As shown, it includes: a substrate, a conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer and an electrode layer stacked in sequence from bottom to top; in the present invention, during the preparation process of the perovskite light-absorbing layer of the above-mentioned wide-bandgap perovskite solar cell, MACl and PEAAc are added to its precursor solution as additives to optimize the performance of the perovskite light-absorbing layer, thereby improving the yield of the wide-bandgap perovskite cell, and enabling the prepared wide-bandgap perovskite solar cell to obtain a high open-circuit voltage and a better cell conversion efficiency, which is beneficial to the commercial application of the wide-bandgap perovskite solar cell.

[0035] Specifically, on the one hand, the present invention can effectively induce the formation of initial nuclei with (100) preferential orientation by adding MACl to the wide bandgap perovskite precursor solution, connect adjacent seed crystals, limit the inclination of grains, and improve the crystallization quality of the perovskite layer; in addition, after the PEAAc solution is added to the perovskite precursor solution, the negatively charged COO- group can be connected to the under-coordinated formamidinium ion (FA) through hydrogen bonds and coordination bonds, respectively. + ) and lead ions (Pb 2+ ) interactions, which can passivate halogen vacancies, enhance the uniform distribution of halide phases and reduce the defect density in perovskite films, thus forming a denser and smoother perovskite film, thereby effectively improving the overall performance of wide-bandgap perovskite solar cells;

[0036] On the other hand, due to the moisture resistance of polymers and good transfer of interface charges, the long-term stability of wide-bandgap perovskite solar cells is significantly improved, thus solving the problem of poor stability caused by the lithium fluoride passivation layer.

[0037] On the other hand, the perovskite layer formed after adding PEAAc in the present invention has good conductivity. Tests have shown that the perovskite solar cell prepared by adding the precursor solution of PEAAc has a stronger carrier extraction ability, which can basically eliminate charge accumulation at the perovskite / 2PACz interface, quickly extract charges, effectively slow down the degradation of perovskite, and improve the long-term stability of wide-bandgap perovskite solar cells.

[0038] In order to further enhance the binding effect between PEAAc and perovskite, the concentration of the PEAAc solution is 0.1 mmol / ml to 0.3 mmol / ml.

[0039] In order to ensure the light absorbing thickness and further reduce the spin coating speed, the thickness of the above-mentioned perovskite light absorbing layer is 300nm to 500nm.

[0040] In order to facilitate the transmission of electrons, the material of the electron transport layer is a wide bandgap semiconductor, for example, fullerene and its derivatives (PCBM); the electron transport layer may include multiple stacked transport sublayers, and the total thickness of the electron transport layer is 10nm to 50nm.

[0041] In order to better extract the carriers generated by the perovskite layer under the irradiation of light, the thickness of the hole transport layer is 20nm to 40nm.

[0042] The specific embodiments of the present invention are described in detail below, and the beneficial effects of the present invention are compared and illustrated in combination with the test results based on the comparative examples.

[0043] Example 1

[0044] This embodiment provides a method for preparing a wide bandgap perovskite solar cell. The structure of the prepared wide bandgap perovskite solar cell is as follows: Figure 1 As shown, the specific steps include:

[0045] Step 1, using acetone to ultrasonically clean the transparent conductive glass substrate (glass substrate covered with a conductive layer) for 15 minutes, and then using ethanol to ultrasonically clean the transparent conductive glass substrate for 15 minutes, and drying the cleaned transparent conductive glass substrate in an oven for later use;

[0046] Step 2: depositing a NiO layer with a thickness of 30 nm on the surface of the transparent conductive glass substrate by a magnetron sputtering process to form a hole transport layer;

[0047] Step 3, dissolving 2PACz in anhydrous ethanol to prepare a 2PACz ethanol solution with a concentration of 1 mg / mL, taking 100 μL of the 2PACz ethanol solution, spin-coating it on the surface of the NiO layer at a speed of 3000 rpm for 30 seconds, and then annealing it on a hot stage at 100° C. for 10 minutes to form a 2PACz layer;

[0048] Step 4: 108.73 mg of FAI, 16.37 mg of CsI, 57.92 mg of MABr, 320.64 mg of PbI2, 208.85 mg of PbBr2 and 8.17 mg of MACl were dissolved in 1 mL of a mixed solvent and stirred for 12 h to obtain a wide bandgap perovskite modified precursor solution, wherein the mixed solvent consists of DMF and DMSO, and the volume ratio of DMF to DMSO is 3:1;

[0049] Step 5, spin-coating the wide bandgap perovskite primary modified precursor solution on the surface of the 2PACz layer, first, spin-coating at an acceleration of 1333 rpm / s for 3 seconds; then, spin-coating at a rotation speed of 4000 rpm for 40 seconds, and adding 0.12 mL of chlorobenzene antisolvent to the spin-coated surface 7 seconds after the current spin coating starts; after the spin coating is completed, the substrate is placed on a hot stage and annealed at a temperature of 100° C. for 60 minutes to form a perovskite light-absorbing layer;

[0050] Step 6: Using vacuum thermal evaporation process, lithium fluoride (LiF) with a thickness of 1 nm and C with a thickness of 10 nm are sequentially deposited on the surface of the perovskite light-absorbing layer. 60 and a BCP with a thickness of 15 nm, forming an electron transport layer;

[0051] Step 7: Deposit silver with a thickness of 120 nm on the surface of the electron transport layer by vacuum thermal evaporation process. During the deposition process, electrode patterning is completed through a mask plate to form an electrode layer, thereby obtaining the following: Figure 1 A wide-bandgap perovskite cell is shown.

[0052] Example 2

[0053] This embodiment provides a method for preparing a wide bandgap perovskite solar cell, and its process is the same as that of Example 1, with the only difference being that in step 4, the mass of MACl is weighed to be 16.34 mg; the other steps are exactly the same, and finally an inverted wide bandgap perovskite solar cell is prepared.

[0054] Example 3

[0055] This embodiment provides a method for preparing a wide bandgap perovskite solar cell, and its process is the same as that of Example 1, with the only difference being that in step 4, the mass of MACl weighed is 24.51 mg; the other steps are exactly the same, and finally an inverted wide bandgap perovskite solar cell is prepared.

[0056] Example 4

[0057] This embodiment prepares a wide bandgap perovskite solar cell, and the structure of the obtained wide bandgap perovskite solar cell is also as shown in FIG. Figure 1 As shown, the specific steps include:

[0058] Step 1, using acetone to ultrasonically clean the transparent conductive glass substrate (glass substrate covered with a conductive layer) for 15 minutes, and then using ethanol to ultrasonically clean the transparent conductive glass substrate for 15 minutes, and drying the cleaned transparent conductive glass substrate in an oven for later use;

[0059] Step 2: depositing a NiO layer with a thickness of 30 nm on the surface of the transparent conductive glass substrate by a magnetron sputtering process to form a hole transport layer;

[0060] Step 3, dissolving 2PACz in anhydrous ethanol to prepare a 2PACz ethanol solution with a concentration of 1 mg / mL, taking 100 μL of the 2PACz ethanol solution, spin-coating it on the surface of the NiO layer at a speed of 3000 rpm for 30 seconds, and then annealing it on a hot stage at 100° C. for 10 minutes to form a 2PACz layer;

[0061] Step 4: 108.73 mg of FAI, 16.37 mg of CsI, 57.92 mg of MABr, 320.64 mg of PbI2, 208.85 mg of PbBr2 and 16.34 mg of MACl were dissolved in 1 mL of a mixed solvent and stirred for 12 h to obtain a wide bandgap perovskite modified precursor solution, wherein the mixed solvent consisted of DMF and DMSO, and the volume ratio of DMF to DMSO was 3:1;

[0062] 18.12 mg of phenylethylammonium acetate (PEAAc) was dissolved in 1 mL of a mixed solvent and stirred for 12 h to prepare a PEAAc solution, wherein the mixed solvent consisted of DMF and DMSO, and the volume ratio of DMF to DMSO was 4:1;

[0063] 40 μL of PEAAc solution was added to 1 mL of wide band gap perovskite modified precursor solution to prepare a wide band gap perovskite mixed modified precursor solution;

[0064] Step 5, spin-coating the wide bandgap perovskite precursor solution on the surface of the 2PACz layer, first, spin-coating at an acceleration of 1333 rpm / s for 3 seconds; then, spin-coating at a rotation speed of 4000 rpm for 40 seconds, and adding 0.12 mL of chlorobenzene antisolvent to the spin-coated surface 7 seconds after the current spin coating starts; after the spin coating is completed, the substrate is placed on a hot stage and annealed at a temperature of 100° C. for 60 minutes to form a perovskite light-absorbing layer;

[0065] Step 6: Using vacuum thermal evaporation process, lithium fluoride (LiF) with a thickness of 1 nm and C with a thickness of 10 nm are sequentially deposited on the surface of the perovskite light-absorbing layer. 60 and a BCP with a thickness of 15 nm, forming an electron transport layer;

[0066] Step 7: Deposit silver with a thickness of 120 nm on the surface of the electron transport layer by vacuum thermal evaporation process. During the deposition process, electrode patterning is completed through a mask plate to form an electrode layer, thereby obtaining the following: Figure 1 A wide-bandgap perovskite cell is shown.

[0067] Example 5

[0068] This embodiment provides a method for preparing a wide bandgap perovskite solar cell, and its process is the same as that of Example 4, with the only difference being that in step 4, 80 μL of PEAAc solution is added to 1 mL of a wide bandgap perovskite precursor initial solution to prepare a wide bandgap perovskite precursor solution; the other steps are exactly the same, and finally an inverted wide bandgap perovskite solar cell is prepared.

[0069] Comparative Example 1

[0070] In this comparative example, a wide bandgap perovskite solar cell was prepared. The preparation process was similar to that of Example 1, except that: 8.17 mg of MACl was weighed in the weighing process of step 4 to prepare a perovskite precursor solution, and LiF, C were directly deposited on the perovskite light-absorbing layer obtained in step 5 by vacuum thermal evaporation. 60 , BCP to obtain an electron transport layer; the other steps are exactly the same. Then an inverted wide bandgap perovskite solar cell is obtained.

[0071] The performance of the perovskite solar cells prepared in the above Examples 1 to 5 and Comparative Example 1 was tested, and the results are shown in Table 1;

[0072] Table 1

[0073]

[0074] As can be seen from Table 1, Examples 1 to 3 show higher open circuit voltage and higher photoelectric conversion efficiency than Comparative Example 1, and have a high fill factor, among which Example 2 has the highest open circuit voltage and photoelectric conversion efficiency; thus, it can be seen that the introduction of MACl as an additive to the perovskite light absorbing layer in the present invention has an excellent defect passivation effect on the perovskite light absorbing layer; further, Examples 4 and 5 have higher open circuit voltage and photoelectric conversion efficiency, proving that PEAAc as an additive to the perovskite light absorbing layer can further significantly improve the open circuit voltage of the device.

[0075] In more detail:

[0076] like Figure 2 FIG. 1 is a schematic diagram of the spin coating annealing process of the hole transport layer and the perovskite light absorbing layer in the above embodiment, from which the preparation process of the perovskite film can be clearly seen;

[0077] like Figure 3The X-ray diffraction (XRD) spectra of the wide bandgap perovskite films prepared in Examples 1 to 3 of the present invention and Comparative Example 1 are shown. It can be seen from the figure that compared with Comparative Example 1, after adding MACl, the intensity of the characteristic peak of perovskite (the corresponding 2θ value of the (100) crystal plane is 14.5°, and the corresponding 2θ value of the (110) crystal plane is 20.5°) in Examples 1 to 3 is greater than that of the characteristic peak of PbX2 (X is Br or I) (the corresponding 2θ value is 12.8°), indicating that the perovskite light-absorbing layer in the present invention has a higher crystalline quality;

[0078] like Figure 4 The external quantum efficiency (EQE) spectra of the wide bandgap perovskite solar cells prepared in Examples 1 to 3 of the present invention and Comparative Example 1 are shown. It can be seen from the figure that compared with Comparative Example 1, after adding MACl, the light absorption of the devices in Examples 1 to 3 is improved, and the surface devices have a higher short-circuit current density;

[0079] like Figure 5 The X-ray diffraction (XRD) patterns of the wide bandgap perovskite films prepared in Example 2, Example 4, Example 5 and Comparative Example 1 of the present invention are shown. It can be seen from the figure that the introduction of MACl into the perovskite light-absorbing layer can effectively improve the intensity of the characteristic peaks of the perovskite (the 2θ value corresponding to the (100) crystal plane is 14.5°, and the 2θ value corresponding to the (110) crystal plane is 20.5°). Furthermore, the addition of PEAAc can further improve the intensity of the characteristic peaks of the perovskite.

[0080] like Figure 6 Shown are the time-resolved photoluminescence (TRPL) spectra of the wide-bandgap perovskite films prepared in Examples 4 to 5 of the present invention and Comparative Example 1. It can be seen from the figure that compared with Comparative Example 1, the normalized intensity of Examples 4 and 5 decreases faster after the addition of PEAAc, indicating that the perovskite films prepared after the addition of PEAAc have better carrier extraction and better charge transfer capability.

[0081] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A method for preparing a wide bandgap perovskite solar cell, characterized in that: The following steps are involved: Step 1, cleaning the transparent conductive glass substrate; Step 2: depositing a hole transport layer on the surface of a transparent conductive glass substrate by a magnetron sputtering process; Step 3, preparing a 2PACz ethanol solution, spin coating it on the surface of the hole transport layer, and then annealing it to form a 2PACz layer; Step 4, preparing a wide bandgap perovskite modified precursor solution, including: an initial perovskite precursor solution and MACl, wherein the molar concentration of MACl is 10% to 30% of the molar concentration of the initial perovskite precursor solution; Step 5, spin coating the wide bandgap perovskite modified precursor solution on the surface of the 2PACz layer and then annealing to form a perovskite light absorbing layer; Step 6: Using a vacuum thermal evaporation process to deposit an electron transport layer on the surface of the perovskite light absorbing layer; Step 7: Use a vacuum thermal evaporation process to deposit an electrode layer on the surface of the electron transport layer to obtain a wide bandgap perovskite cell.

2. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 1, the cleaning process is: using acetone to ultrasonically clean the transparent conductive glass substrate for 10 minutes to 20 minutes, then using ethanol to ultrasonically clean the transparent conductive glass substrate for 10 minutes to 20 minutes, and drying it in an oven for later use.

3. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 2, the hole transport layer is a nickel oxide layer.

4. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 3, the concentration of the 2PACz ethanol solution is 1 mg / mL to 3 mg / mL, and the spin coating process is: spin coating the 2PACz ethanol solution on the surface of the hole transport layer at a speed of 2000 rpm to 5000 rpm, and the spin coating time is 30s to 40s; the annealing process is: annealing at a temperature of 100°C to 150°C for 10min to 20min.

5. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 4, the wide bandgap perovskite modified precursor solution further includes: PEAAc, and the molar concentration of PEAAc is 0.2% to 0.8% of the molar concentration of the initial perovskite precursor solution.

6. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 4, the molar ratio of CsI, MABr, FAI, PbI2 and PbBr2 in the initial perovskite precursor solution is 0.05:0.43:0.52:0.57:0.

47.

7. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 5, the spin coating process is as follows: first, the precursor solution of the perovskite light absorbing layer is spin coated at an acceleration of 800rpm / s to 1500rpm / s for 3s to 8s; then, the spin coating is performed at a rotation speed of 4000rpm to 6000rpm for 40s, and 0.1mL to 0.2mL of chlorobenzene antisolvent is added to the surface 5s to 15s after the start of the current spin coating; the annealing process is as follows: annealing at a temperature of 100°C to 150°C for 30min to 60min.

8. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 6, the electron transport layer is composed of lithium fluoride (LiF), carbon 60 layer (C 60 ), 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline layer (BCP) are stacked in sequence.

9. The method for preparing a wide bandgap perovskite solar cell according to claim 1, characterized in that: In step 7, the metal used for the electrode layer is silver (Ag) or gold (Au).

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