CN115020595A - Interface modified tin-lead mixed perovskite solar cell and preparation method thereof - Google Patents

Abstract

The invention provides an interface modified tin-lead mixed perovskite solar cell and a preparation method thereof, and belongs to the technical field of solar cells. The interface modified tin-lead perovskite solar cell comprises a conductive glass layer, PEDOT, PSS layer, a modifying layer and FA which are sequentially distributed in a layered manner _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The modified graphene film comprises a polycrystalline film, an electron transmission layer and a metal electrode layer, wherein the modification layer is made of nitrogen and chlorine co-doped graphene quantum dots. According to the invention, the energy level arrangement which is most matched with a perovskite layer is induced by utilizing the enhancement of the P type doping of the nitrogen and chlorine co-doped graphene quantum dots, the nitrogen and chlorine co-doped graphene quantum dots can passivate defect states on an interface through the conjugated pi effect and the electronegativity of Cl of the graphene quantum dots, the efficiency of interface charge transmission can be improved, and the photoelectric conversion efficiency and the open-circuit voltage of the tin-lead mixed perovskite solar cell are further improved.

Description

Interface modified tin-lead mixed perovskite solar cell and preparation method thereof

Technical Field

The invention relates to the technical field of solar cells, in particular to an interface modified tin-lead mixed perovskite solar cell and a preparation method thereof.

Background

Compared with traditional single crystal silicon solar cells and novel thin-film solar cells such as dye-sensitized solar cells and organic solar cells, the perovskite solar cell is lower in cost, simpler to prepare, more diverse in process, capable of meeting richer market demands, high in photoelectric conversion efficiency, and highly valued in scientific research and the industry. Perovskite materials have been used in solar cells since 2009 with an initial efficiency of 3.8% and until recently, the photovoltaic efficiency has reached 25.5%, with extremely rapid development, creating a history in the photovoltaic field. Perovskite solar cells are nonetheless an ideal choice for the next generation of photovoltaic devices. Whereas the narrow band gap (<1.3eV) tin-lead mixed perovskite solar cells are of interest for their application in tandem solar cell technology. However, the current tin-lead mixed perovskite solar cell still has the problems of low photoelectric conversion efficiency and low open-circuit voltage, and the development of the tin-lead mixed perovskite solar cell is hindered.

Disclosure of Invention

The invention aims to provide an interface modified tin-lead mixed perovskite solar cell with high photoelectric conversion efficiency and high open-circuit voltage.

In order to solve the above problems, the present invention adopts the following technical solutions.

An interface modified tin-lead perovskite solar cell comprises a conductive glass layer, PEDOT, PSS layer, a modifying layer and FA in sequence which are distributed in a layered manner _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The polycrystalline film, the electron transmission layer and the metal electrode layer, wherein the modification layer is made of nitrogen and chlorine co-doped graphiteAnd (3) an olefinic quantum dot.

Compared with the prior art, the N and Cl co-doped graphene quantum dots (N, Cl-GQDs) are used as the modification layer of the tin-lead perovskite solar cell, and the energy level arrangement which is most matched with the perovskite layer is induced by utilizing the enhancement of the P type doping of the N and Cl co-doped graphene quantum dots. In addition, the nitrogen and chlorine co-doped graphene quantum dots can passivate defect states on an interface through the conjugated pi effect of the graphene quantum dots and the electronegativity of Cl, so that the efficiency of interface charge transmission can be improved, and further the photoelectric conversion efficiency and the open-circuit voltage of the tin-lead mixed perovskite solar cell are improved.

Further, the FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The polycrystalline film preparation method comprises the following steps:

d1, SnF ₂ Dissolving in DMF/DMSO to form solution A, adding SnI into the solution A ₂ And preparation of FASnI from FAI ₃ Precursor solution;

d2, FASnI prepared in step D1 ₃ Adding excessive Sn powder into the precursor solution, and filtering by using a filter head to obtain FASnI ₃ A solution;

d3, adding PbSCN into DMF/DMSO to form solution B, and adding PbI into solution B ₂ And MAI preparation of MAPbI ₃ A solution;

d4, and mixing the FASnI obtained in the step D2 ₃ Solution and step D3 to obtain MAPbI ₃ The solution is according to FASnI ₃ :MAPbI ₃ Mixing at a stoichiometric ratio of 6:4 to obtain FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A solution;

d5, and using the FA obtained in the step D4 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Spin coating the solution on the modifying layer to form FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A polycrystalline film.

By the above method, FA can be prepared _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The preparation method of the polycrystalline film does not need conditions such as high temperature and high pressure, and the process is simple.

Further, in step D1, SnF in the solution A ₂ Is 10 mol%, the SnI ₂ And the molar ratio of the FAI is 1: 1. By controlling SnI ₂ The molar ratio of the FAI to the FASnI is 1:1, which is favorable for preparing FASnI ₃ 。

Further, in step D3, the concentration of PbSCN in the solution B is 5 mol%, and the PbI is ₂ And the molar ratio of the MAI is 1: 1. By controlling PbI ₂ The molar ratio of the monomer to the MAI is favorable for preparing the FASnI ₃ 。

Further, in the interface modified tin-lead perovskite solar cell, the preparation method of the nitrogen and chlorine co-doped graphene quantum dots comprises the following steps:

s1, dissolving citric acid and 3, 4-dichloroaniline in isopropanol to form a mixed solution;

s2, transferring the mixed solution obtained in the step S1 into an autoclave, and heating for a period of time at a certain temperature;

s3, cooling the autoclave in the step S2 to room temperature, centrifuging to remove large particles, and collecting yellow supernatant, wherein the yellow supernatant is nitrogen and chlorine co-doped graphene quantum dot solution;

and S4, further filtering the nitrogen and chlorine co-doped graphene quantum dot solution obtained in the step S3 through microporous filter paper, dialyzing for one week through a dialysis bag, and purifying to obtain the nitrogen and chlorine co-doped graphene quantum dot solid.

By the method, the nitrogen and chlorine co-doped graphene quantum dot can be prepared, and the preparation method is simple and feasible in steps.

In step S1, the molar ratio of the citric acid to the dichloroaniline is 1:1, and the concentrations of the citric acid and the 3, 4-dichloroaniline in the mixed solution are 67 to 80 mmol/L. By controlling the molar ratio and the concentration of the citric acid and the 3, 4-dichloroaniline, the citric acid and the 3, 4-dichloroaniline can react in proportion to generate the nitrogen and chlorine co-doped graphene quantum dots in the subsequent steps.

Further, the heating temperature in step S2 is 180-190 ℃, and the heating time is 20-30 h. By controlling the reaction time and the reaction temperature, the synthesis reaction of the nitrogen and chlorine co-doped graphene quantum dots can be smoothly carried out.

The invention also provides the nitrogen and chlorine co-doped graphene quantum dot prepared by the preparation method. The prepared nitrogen and chlorine co-doped graphene quantum dot is doped in a P type manner and has good electrical conductivity and thermal conductivity.

Further, the invention also provides a preparation method of the interface modified tin-lead perovskite solar cell, which specifically comprises the following steps:

f1, diluting the PEDOT PSS solution into a PEDOT PSS aqueous solution, spin-coating the PEDOT PSS aqueous solution on the conductive glass layer, and annealing to form a PEDOT PSS layer;

f2, spin-coating an isopropanol solution of the nitrogen and chlorine co-doped graphene quantum dots on the PEDOT PSS layer prepared in the step F1, then annealing, volatilizing the isopropanol, and forming a modification layer on the PEDOT PSS layer.

F3, adding FA with the concentration of 1.4mol/L in a nitrogen atmosphere _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Spin coating the solution on the modified layer prepared in step F2, and annealing to form FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Polycrystalline film of said FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The solvent of the solution is DMF and DMSO, and the volume ratio of the DMF to the DMSO is 4: 1.

F4, passivation of FA prepared in step F3 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Carrying out polycrystalline film;

f5: spin-coating a solution of fullerene derivative in chlorobenzene to FA for completion of step F4 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Annealing the polycrystalline film to form a fullerene film, and finally, forming a fullerene film on FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Forming an electron transport layer on the polycrystalline film;

f6: and evaporating the silver electrode on the electron transport layer.

Further, the spin coating time in step F2 was 30S, and the spin speed was 4000 rpm. By controlling the spin coating time and the spin coating speed, the film forming quality and the film forming speed of the modified layer can be controlled, and the photoelectric conversion efficiency and the open-circuit voltage of the prepared interface modified tin-lead perovskite solar cell are improved.

Drawings

FIG. 1 is a graph of EQE and integrated current density for the cells of example 1 and comparative example 6;

FIG. 2 is a transient photocurrent decay curve for the cells of example 1 and comparative example 6;

FIG. 3 is a graph showing the transient photovoltage decay curves of the cells of example 1 and comparative example 6;

FIG. 4 shows FA in example 1 and comparative example 6 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ SEM plane and cross-sectional views of polycrystalline films;

FIG. 5 is a plot of the SCLC of the cells of example 1 and comparative example 6;

fig. 6 is a graph showing the efficiency stability of the cells of example 1 and comparative example 6.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment provides an interface modified tin-lead perovskite solar cell which comprises a conductive glass layer, a PEDOT (poly (3, 4-ethylenedioxythiophene): PSS (poly (styrenesulfonic acid)) layer, a modification layer and FA (FA) which are sequentially distributed in a layered manner _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Polycrystal membrane, electron transport layer and metal electrode layer, the material of modification layer is nitrogen, chlorine codope graphite alkene quantum dot.

Compared with the prior art, in the embodiment, nitrogen and chlorine co-doped graphene quantum dots (N, Cl-GQDs) are used as the modification layer of the tin-lead perovskite solar cell, and the energy level arrangement most matched with the perovskite layer is induced by utilizing the enhancement of P-type doping of the nitrogen and chlorine co-doped graphene quantum dots. In addition, the nitrogen and chlorine co-doped graphene quantum dots can passivate defect states on an interface through the conjugated pi effect of the graphene quantum dots and the electronegativity of Cl, so that the efficiency of interface charge transmission can be improved, and further the photoelectric conversion efficiency and the open-circuit voltage of the tin-lead mixed perovskite solar cell are improved.

Example 2

This example provides an FA used in example 1 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The preparation method of the polycrystalline film comprises the following steps:

d1, adding 0.3725g of SnI ₂ And 0.172g of FAI with 10 mol% of SnF ₂ Preparation of FASnI in DMF/DMSO (8:2) ₃ A solution;

d2, FASnI prepared in step D1 ₃ Adding excessive Sn powder into the precursor solution, and filtering by using a 0.22 mu m filter head to obtain FASnI ₃ And (3) solution.

D3, 0.461g of PbI dissolved in DMF/DMSO (8:2) with 5 mol% of PbSCN ₂ And 0.159gMAI preparation of MAPbI ₃ A precursor solution;

d4, and mixing the FASnI obtained in the step D2 ₃ Solution and MAPbI obtained in step D3 ₃ The solution was prepared according to FASnI ₃ :MAPbI ₃ Mixing at a stoichiometric ratio of 6:4 to obtain FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A solution;

d5, spin-coating the perovskite solution obtained in the step D4 on the modification layer to form FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A polycrystalline film.

Example 3

The embodiment provides a preparation method of a nitrogen and chlorine co-doped graphene quantum dot, which comprises the following steps:

s1, dissolving citric acid (5mmol) and 3, 4-dichloroaniline (5mmol) in 75mL isopropanol to form a mixed solution;

s2, transferring the mixed solution obtained in the step S1 into a 100mL autoclave with a polytetrafluoroethylene lining, and heating the mixture for 24 hours at 180 ℃;

s3, cooling the high pressure processed in the step S2 to room temperature, centrifuging the solution at 8000rpm for 10 minutes, removing large particles, and collecting yellow supernatant as a nitrogen and chlorine co-doped graphene quantum dot (N, Cl-GQDs) solution;

s4, filtering the N, Cl-GQDs solution obtained in the step S3 through 0.22-micron microporous filter paper, dialyzing for one week through a dialysis bag (100-500 Da), and preserving the purified N, Cl-GQDs solid at the temperature of 4 ℃ for further use.

Example 4

The embodiment provides another preparation method of a nitrogen and chlorine co-doped graphene quantum dot, which comprises the following steps:

s1, dissolving citric acid (6mmol) and 3, 4-dichloroaniline (6mmol) in 75mL isopropanol to form a mixed solution;

s2, transferring the mixed solution obtained in the step S1 into a 100mL autoclave with a polytetrafluoroethylene lining, and heating the autoclave at 190 ℃ for 30 hours;

s3, cooling the high pressure processed in the step S2 to room temperature, centrifuging the solution at 8000rpm for 10 minutes, removing large particles, and collecting yellow supernatant as a nitrogen and chlorine co-doped graphene quantum dot (N, Cl-GQDs) solution;

s4, filtering the N, Cl-GQDs solution obtained in the step S3 through 0.22 mu m microporous filter paper, dialyzing for one week through a dialysis bag (100-500 Da), and storing the purified N, Cl-GQDs solid at the temperature of 4 ℃ for further use.

Example 5

The embodiment provides a method for preparing an interface modified tin-lead perovskite solar cell in embodiment 1, which includes the following steps:

f1: diluting a PEDOT/PSS solution and water according to the proportion of 1:3 to obtain a PEDOT/PSS aqueous solution, spin-coating the PEDOT/PSS aqueous solution on the conductive glass layer, and annealing to form a PEDOT/PSS layer, wherein the spin-coating speed is 4000rpm, the spin-coating time is 30s, the annealing temperature is 150 ℃, and the annealing time is 15 min;

f1: spinning 120 microliter of isopropanol solution of N, Cl-GQDs on the PEDOT PSS layer for 30s at the rotation speed of 4000rpm, and then annealing at 100 ℃ for 5min to completely volatilize the isopropanol so as to form a modification layer on the PEDOT PSS layer;

f3: FA is reacted under nitrogen atmosphere _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Solutions (FA) _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Concentration 1.4mol/L, solvent DMF and DMSO in a volume ratio of 4:1) was spin-coated onto the PEDOT: PSS layer at 4000rpm for 30s, followed by annealing at 100 ℃ to form FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A polycrystalline film;

f4: using EDA (0.1 mmol/L in isopropanol) molecule vs. FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Passivating the layer by spin coating at 5000 rpm for 50 s and heating at 100 deg.C for 5 min;

f5: a chlorobenzene solution of fullerene derivative PCBM (PCBM concentration of 7.5mg/ml) was spin-coated to FA at 2500rpm _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Spin-coating on the polycrystalline film for 30s, annealing at 40 deg.C for 5min to form PCBM film with C60 of 20nm and BCP of 7nm, and finally performing annealing at FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Forming an electron transport layer on the polycrystalline film;

f6: and a silver electrode with the thickness of 80nm is evaporated on the electron transport layer.

Comparative example 6:

this example provides a method for preparing a tin-lead perovskite solar cell without interface modification, which is different from example 5 in that step F2 is not included, and other steps are the same as example 5, and accordingly FA is used _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The solution was spin coated on the PEDOT: PSS layer instead of the finish layer.

The tin-lead perovskite solar cell prepared by the comparative example comprises a conductive glass layer, a PEDOT (Poly ethylene glycol ether ketone) PSS layer, a FA0.6MA0.4Sn0.6Pb0.4I3 polycrystalline film, an EDA passivation layer, an electron transport layer and a metal electrode layer which are sequentially distributed in a layered manner.

Characterization of the test

In a room temperature environment, a xenon lamp is used for simulating sunlight, and the light intensity is 95.6mW/cm ² Photoelectric performance tests (effective illumination area of 0.075 cm) were carried out on the Sn-Pb perovskite solar cells of comparative example 6 and example 1, respectively, under the condition of a solar simulator (model: Newport 91192A) ² ) The test results are shown in Table 1.

TABLE 1

It can be seen that by placing N, Cl-GQDs as a modification layer on PEDOT, PSS layer and FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Among the polycrystalline films, the polycrystalline film has good promotion effects on the short-circuit current, the open-circuit voltage and the fill factor of the battery, and particularly the promotion of the open-circuit voltage and the fill factor is obvious.

The improvement effect of the modification layer on the short-circuit current density is limited, and in order to eliminate the influence of experimental errors, the External Quantum Efficiency (EQE) and the integrated current density of comparative example 6 (original sample) and example 1(N, Cl-GQDs modification sample) are respectively tested, which is shown in fig. 1. It can be seen that, in the whole interval, the EQE of the solar cell in the embodiment 1(N, Cl-GQDs modified sample) is obviously improved compared with the comparative example 6 (original sample), and correspondingly, the integrated current density in the embodiment 1 is slightly higher than that in the comparative example, which is more in line with the improvement effect of N, Cl-GQDs on the short-circuit current density, so that the improvement effect of N, Cl-GQDs on the short-circuit current density is proved.

Referring to FIG. 2, the TPC response time is reduced from 14 mus to 7 mus through the modification effect of N, Cl-GQDs on PEDOT: PSS, and the N, Cl-GQDs are proved to have good promotion effect on the extraction and transmission of carriers.

Referring to FIG. 3, the TPV response time is increased from 0.44ms to 0.74ms by the modification effect of N, Cl-GQDs on PEDOT: PSS, which proves that N, Cl-GQDs have obvious inhibition effect on carrier recombination.

With reference to FIG. 4, FA may be obtained by modification of PEDOT: PSS by N, Cl-GQDs _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The polycrystalline film shows that the crystal grains of the perovskite film growing on the modified sample are obviously increased, which shows that the modified sample can improve the film forming quality.

Referring to FIG. 5, by the modification of PEDOT: PSS by N, Cl-GQDs, it can be seen from FA0.6MA0.4Sn0.6Pb0.4I3 polycrystalline film that the defect filling voltage of perovskite growing on the modified form is reduced from 0.45V to 0.29V, consistent with the above-mentioned grain enlargement effect, and the defect state density can be reduced by the grain enlargement.

Referring to fig. 6, the stability of the battery efficiency in comparative example 6 (as it is) and example 1(N, Cl-GQDs modified sample) under different conditions was compared. Under nitrogen conditions, the cell efficiency in comparative example 6 was only 78% of the initial efficiency over 1000h, while the cell efficiency in example 1 was still 92% of the initial efficiency.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and such changes and modifications will fall within the scope of the present invention.

Claims (10)

1. The interface-modified tin-lead perovskite solar cell is characterized by comprising a conductive glass layer, PEDOT, a PSS layer, a modification layer and FA which are sequentially distributed in a layered manner _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The modified graphene film comprises a polycrystalline film, an electron transmission layer and a metal electrode layer, wherein the modification layer is made of nitrogen and chlorine co-doped graphene quantum dots.

2. The interface-modified tin-lead perovskite solar cell of claim 1, wherein the FA is _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The preparation method of the polycrystalline film comprises the following steps:

d1, SnF ₂ Dissolved inForming a solution A in DMF/DMSO, adding SnI into the solution A ₂ And preparation of FASnI from FAI ₃ Precursor solution;

d2, FASnI prepared in step D1 ₃ Adding excessive Sn powder into the precursor solution, and filtering by using a filter head to obtain FASnI ₃ A solution;

d3, adding PbSCN into DMF/DMSO to form solution B, and adding PbI into solution B ₂ And MAI preparation of MAPbI ₃ A solution;

d4, and mixing the FASnI obtained in the step D2 ₃ Solution and MAPbI obtained in step D3 ₃ The solution is according to FASnI ₃ :MAPbI ₃ Mixing at a stoichiometric ratio of 6:4 to obtain FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A solution;

d5, and using the FA obtained in the step D4 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Spin coating the solution on the modifying layer to form FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A polycrystalline film.

3. The interface-modified sn-pb perovskite solar cell of claim 2, wherein in step D1, SnF in the solution a ₂ Is 10 mol%, the SnI ₂ And the molar ratio of the FAI is 1: 1.

4. The interface-modified sn-pb perovskite solar cell of claim 2, wherein in step D3, the concentration of PbSCN in solution B is 5 mol%, and the PbI is ₂ And the molar ratio of the MAI is 1: 1.

5. The interface modification tin-lead perovskite solar cell according to claim 1, wherein the preparation method of the nitrogen and chlorine co-doped graphene quantum dot comprises the following steps:

s1, dissolving citric acid and 3, 4-dichloroaniline in isopropanol to form a mixed solution;

s2, transferring the mixed solution obtained in the step S1 into an autoclave, and heating for a period of time at a certain temperature;

s3, cooling the autoclave which completes the step S2 to room temperature, centrifuging to remove large particles, and collecting yellow supernatant, wherein the yellow supernatant is a nitrogen and chlorine co-doped graphene quantum dot solution;

and S4, filtering the nitrogen and chlorine co-doped graphene quantum dot solution obtained in the step S3 through microporous filter paper, dialyzing for one week through a dialysis bag, and purifying to obtain the nitrogen and chlorine co-doped graphene quantum dot solid.

6. The interface-modified tin-lead perovskite solar cell of claim 5, wherein the molar ratio of the citric acid to the dichloroaniline in step S1 is 1:1, and the concentration of the citric acid and the 3, 4-dichloroaniline in the mixed solution is 67-80 mmol/L.

7. The interface-modified Sn-Pb perovskite solar cell of claim 6, wherein the heating temperature in the step S2 is 180-190 ℃ and the heating time is 20-30 h.

8. The nitrogen and chlorine co-doped graphene quantum dot is characterized by being prepared by the preparation method of the nitrogen and chlorine co-doped graphene quantum dot according to any one of claims 5 to 7.

9. A method for preparing the interface modified tin-lead perovskite solar cell according to claim 1, which comprises the following steps:

f1, diluting the PEDOT PSS solution into a PEDOT PSS aqueous solution, spin-coating the PEDOT PSS aqueous solution on the conductive glass layer, and annealing to form a PEDOT PSS layer;

f2, spin-coating an isopropanol solution of the nitrogen and chlorine co-doped graphene quantum dots on the PEDOT PSS layer prepared in the step F1, then annealing to volatilize the isopropanol, and forming a modification layer on the PEDOT PSS layer;

f3, adding FA with the concentration of 1.4mol/L in a nitrogen atmosphere _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Spin coating the solution on the modified layer prepared in step F2, and annealing to form FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Polycrystalline film of said FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ The solvent of the solution is DMF and DMSO, and the volume ratio of the DMF to the DMSO is 4: 1;

f4 passivating FA prepared in step F3 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ A polycrystalline film;

f5: spin-coating a solution of fullerene derivative in chlorobenzene to FA for completion of step F4 _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Annealing the polycrystalline film to form a fullerene film, and finally, forming a fullerene film on FA _0.6 MA _0.4 Sn _0.6 Pb _0.4 I ₃ Forming an electron transport layer on the polycrystalline film;

f6: and evaporating a silver electrode on the electron transport layer.

10. The method according to claim 9, wherein the spin-coating time in step F2 is 30s, and the spin-coating speed is 4000 rpm.

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