CN108922972B - Perovskite thin film, perovskite solar cell and preparation method thereof - Google Patents

Abstract

The invention relates to a perovskite thin film, a perovskite solar cell and a preparation method thereof. The perovskite thin film comprises perovskite ABX₃Organic-inorganic hybrid materials and polymers obtained by polymerizing acrylate monomers. The preparation method comprises the following steps: mixing acrylate monomer, AX and BX₂Dissolving in a solvent to obtain a perovskite precursor solution; forming the perovskite precursor solution on a substrate; sequentially carrying out annealing treatment and illumination treatment on the substrate with the perovskite precursor solution to obtain a perovskite thin film; wherein the acrylate undergoes polymerization during the light treatment. The perovskite thin film protects the perovskite crystal boundary, and the stability of the perovskite thin film is good. The perovskite solar cell and the preparation method thereof are applied, so that the perovskite solar cell has high conversion efficiency and good stability.

Description

Perovskite thin film, perovskite solar cell and preparation method thereof

technical field

The invention relates to the technical field of solar cells, in particular to a perovskite thin film, a perovskite solar cell and a preparation method thereof.

Background technique

The high efficiency and low cost of perovskite solar cells have attracted extensive attention in recent years. At present, the biggest bottleneck restricting the practical application of perovskite solar cells lies in their stability. Therefore, how to maximize its stability while maintaining its high efficiency becomes a very meaningful research direction.

The stability of perovskite solar cells depends to some extent on the stability of perovskite thin films. In the traditional preparation method of perovskite thin film, the perovskite thin film prepared by solution method usually contains a lot of surface and grain boundary defects, which causes water and oxygen in the air to penetrate into the interior of the perovskite through these defects. This in turn causes the decomposition of perovskite. At the same time, since the interfacial defects are unstable in energy and are easily attacked by external factors (such as illumination, electric field, heating, etc.), the decomposition of perovskite will also be accelerated. Therefore, in order to improve the stability of perovskite films, it is necessary to protect the grain boundaries of perovskite.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a perovskite film and a preparation method for the unstable problem of the perovskite film. The perovskite film protects the perovskite grain boundary, and the perovskite film has good stability. ; Applying it to a perovskite solar cell and its preparation method can make the perovskite solar cell have high conversion efficiency and good stability.

A perovskite thin film, the perovskite thin film comprises a perovskite ABX ₃ organic-inorganic hybrid material and a polymer, and the polymer is obtained by polymerizing an acrylate monomer.

In the above perovskite film, the polymer contains C=O functional groups and C=C functional groups, wherein the C=O functional groups can interact with B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) at the perovskite grain boundaries. ) through the weak interaction of coordination bonds, the growth of the perovskite film can be effectively regulated, so the perovskite film is uniform and dense without obvious voids, and the grain boundary defects of the perovskite film are effectively passivated, thereby improving the perovskite film. Stability of titanite thin films. At the same time, the coordination between C=O functional groups and B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) can make the polymer effectively attach to the grain boundary, thereby forming a dense protective layer at the grain boundary. In turn, the decomposition of water, oxygen and external factors on the perovskite is blocked, and the stability of the perovskite battery is improved. Therefore, the polymer can not only serve as a protective layer for perovskite grain boundaries, but also passivate the defects of grain boundaries, which can synergistically improve the stability of perovskite thin films.

In one embodiment, the acrylate monomer is one or more of methyl methacrylate, ethyl methacrylate, and ethyl cyanoacrylate.

In one embodiment, the mass percentage of the polymer in the perovskite film is 0.3% to 2%.

In one embodiment, in the perovskite ABX ₃ organic-inorganic hybrid material, A is an organic amine cation, B is any one of Pb ²⁺ , Sn ²⁺ , and Ge ²⁺ , and X is a halogen anion or SCN ^- .

A preparation method of a perovskite film, the preparation method comprises the following steps:

Dissolving acrylate monomers, AX and BX ₂ in a solvent to obtain a perovskite precursor solution;

forming the perovskite precursor solution on a substrate;

The substrate with the perovskite precursor solution is sequentially subjected to annealing treatment and light treatment to obtain a perovskite thin film; wherein, the acrylate undergoes a polymerization reaction during the light treatment process.

In the above-mentioned preparation method of the perovskite thin film, the acrylate monomer in the perovskite precursor solution can spontaneously undergo a polymerization reaction under the action of light to obtain a polymer. The reaction step is simple and easy to implement, no other reaction conditions are required, and it is easy to industrialize.

During the reaction process, the acrylate contains C=O functional group and C=C functional group, wherein the C=O functional group and B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) at the perovskite grain boundary through coordination A weak interaction occurs between the bit bonds, which passivate the grain boundary defects. At the same time, the coordination between C=O functional group and B (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) can make the polymer effectively attach to the grain boundary. After light treatment, the C=C functional group in the acrylate A polymerization reaction occurs, thereby forming a dense protective layer at the grain boundary, blocking the decomposition of water, oxygen and external factors on the perovskite, and improving the stability of the perovskite film.

In one embodiment, A in the AX is an organic amine cation, X is a halogen anion or SCN ⁻ ; B in the BX ₂ is any one of Pb ²⁺ , Sn ²⁺ , Ge ²⁺ .

In one embodiment, the temperature of the annealing treatment is 80° C.˜100° C., and the time is 5 min˜10 min.

In one embodiment, the irradiation treatment is ultraviolet, infrared, or sunlight irradiation, and the time is 5 min to 30 min.

A perovskite solar cell, comprising a stacked hole transport layer, a perovskite thin film and an electron transport layer, the perovskite thin film comprising a perovskite ABX ₃ organic-inorganic hybrid material and a polymer, The polymer is obtained by polymerizing acrylate monomers.

The above perovskite films are uniform and dense, without obvious voids, and the perovskite films have excellent stability. Therefore, perovskite solar cells using the above perovskite thin films not only have high conversion efficiency, but also have good stability.

A preparation method of a perovskite solar cell, the preparation method comprises the following steps:

providing a substrate;

forming a hole transport layer on the substrate; and

A perovskite thin film is formed on the hole transport layer using the above-mentioned preparation method; and

forming an electron transport layer on the perovskite film; and

An electrode is formed on the electron transport layer.

The above-mentioned preparation method of the perovskite solar cell has the advantages of being simple and easy to operate. The obtained perovskite solar cells have high conversion efficiency and good stability.

Description of drawings

Fig. 1 is the infrared spectrum diagram of the perovskite film before and after the light treatment of the embodiment 1 of the present invention, in the figure, a is the infrared curve of the perovskite film after the light treatment, b is the perovskite film before the light treatment Infrared curve;

Fig. 2 is the plane and cross-sectional SEM images of the perovskite films prepared in Example 1 and Comparative Example 1 of the present invention, in the figure, b is the plane SEM image of the perovskite films prepared in Example 1, and d is an embodiment 1 is the cross-sectional SEM image of the perovskite film prepared, a is the plane SEM image of the perovskite film prepared in Comparative Example 1, and c is the cross-sectional SEM image of the perovskite film prepared in Comparative Example 1;

Fig. 3 is the steady-state fluorescence spectrogram of the perovskite thin film prepared in Example 1 and Comparative Example 1 of the present invention, in the figure, c is the fluorescence spectrogram of the perovskite thin film of Comparative Example 1, and d is the perovskite thin film of Example 1 Fluorescence spectrum of the titanium ore thin film;

4 is a time-resolved fluorescence spectrum diagram of the perovskite films prepared in Example 1 of the present invention and Comparative Example 1, in the figure, e is the time-resolved fluorescence spectrum of the perovskite film of Example 1, and f is the Fluorescence spectra of perovskite films;

Fig. 5 is the X-ray diffraction (XRD) pattern comparison diagram of the perovskite thin film prepared in Example 1 of the present invention and Comparative Example 1, in the figure, h is the X-ray diffraction curve of the perovskite thin film of Comparative Example 1, and g is The X-ray diffraction curve of the perovskite film of Example 1;

6 is a schematic structural diagram of a perovskite solar cell of the present invention, in the figure, 1 is a substrate, 2 is a hole transport layer, 3 is a perovskite film, 4 is an electron transport layer, and 5 is an electrode;

Fig. 7 is the stability comparison diagram of the perovskite solar cell of Example 7 of the present invention and the comparative example 2, in the figure, i is the stability of the perovskite solar cell of Example 7 in air, j is the comparative example 2 Stability of perovskite solar cells in air.

Detailed ways

The perovskite thin film, the perovskite solar cell and the preparation method thereof provided by the present invention will be further described below.

The perovskite thin film provided by the present invention includes a perovskite ABX ₃ organic-inorganic hybrid material and a polymer, and the polymer is obtained by polymerizing an acrylate monomer.

The mass percentage of the polymer in the perovskite film is 0.3% to 2%. When the perovskite film is applied, such as in a perovskite solar cell, considering the improvement effect of the polymer on the conversion efficiency and stability of the cell, preferably, the polymer in the perovskite film The mass percentage is 0.3% to 1%.

In the perovskite ABX ₃ organic-inorganic hybrid material, A is an organic amine cation, B is any one of Pb ²⁺ , Sn ²⁺ , and Ge ²⁺ , and X is a halogen anion or SCN ⁻ . Preferably, the A is any one of CH ₃ NH ₃ ⁺ , HC(NH ₂ ) ₂ ⁺ , CH ₃ CH ₂ NH ₃ ⁺ , and the X is any one of Cl ^- , Br ^- , and I ^- kind. Since the electron and hole diffusion lengths of CH ₃ NH ₃ PbI ₃ are 130 nm and 100 nm, respectively, the band gap is 1.51 eV, and the absorption is good in the range of 400 nm to 800 nm, the perovskite ABX ₃ organic - The inorganic hybrid material is further preferably CH ₃ NH ₃ PbI ₃ .

The acrylate monomer is one or more of methyl methacrylate, ethyl methacrylate and ethyl cyanoacrylate. Since the cyano group in ethyl cyanoacrylate can also weakly interact with B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.), it is more beneficial to passivate grain boundary defects and improve the stability of perovskite films. sex. At the same time, ethyl cyanoacrylate can be polymerized under mild conditions (light or spontaneous polymerization in air), which is easy to realize the low temperature solution method to prepare perovskite thin films. In addition, ethyl cyanoacrylate is a liquid at room temperature, which is easier to incorporate into the perovskite precursor solution, and its content in perovskite films can be adjusted in a wide range. Therefore, the acrylate is further preferably methyl cyanoacrylate.

In the above perovskite film, the polymer contains C=O functional groups and C=C functional groups, wherein the C=O functional groups can interact with B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) at the perovskite grain boundaries. ) through the weak interaction of coordination bonds, the growth of the perovskite film can be effectively regulated, so the perovskite film is uniform and dense without obvious voids, and the grain boundary defects of the perovskite film are effectively passivated, thereby improving the perovskite film. Stability of titanite thin films. At the same time, the coordination between C=O functional groups and B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) can make the polymer effectively attach to the grain boundary, thereby forming a dense protective layer at the grain boundary. In turn, the decomposition of water, oxygen and external factors on the perovskite is blocked, and the stability of the perovskite battery is improved. Therefore, the polymer can not only serve as a protective layer for perovskite grain boundaries, but also passivate the defects of grain boundaries, which can synergistically improve the stability of perovskite thin films.

The present invention also provides a preparation method of the perovskite film, the preparation method comprising the following steps:

S1, dissolve the acrylate monomer, AX and BX ₂ in a solvent to obtain a perovskite precursor solution;

S2, forming the perovskite precursor solution on a substrate;

S3, sequentially performing annealing treatment and light treatment on the substrate with the perovskite precursor solution to obtain a perovskite thin film; wherein, the acrylate undergoes a polymerization reaction during the light treatment process.

In step S1, the molar ratio of BX ₂ and AX is 1:(0.8-1.2), preferably 1:1.

A in the AX is an organic amine cation, and X is a halogen anion or SCN ⁻ . Preferably, the A is any one of CH ₃ NH ₃ ⁺ , HC(NH ₂ ) ₂ ⁺ , CH ₃ CH ₂ NH ₃ ⁺ , and the X is any one of Cl ^- , Br ^- , and I ^- kind. Since the perovskite ABX ₃ organic-inorganic hybrid material is further preferably CH ₃ NH ₃ PbI ₃ , the corresponding AX is preferably CH ₃ NH ₃ I.

B in the BX ₂ is any one of Pb ²⁺ , Sn ²⁺ , and Ge ²⁺ , and X is a halogen anion or SCN ⁻ . Preferably, the B is one of Pb ²⁺ and Sn ²⁺ , and the X is any one of Cl ⁻ , Br ⁻ , and I ⁻ . Since the perovskite ABX ₃ organic-inorganic hybrid material is further preferably CH ₃ NH ₃ PbI ₃ , the BX ₂ is preferably PbI ₂ correspondingly.

The solvent is a mixed solvent composed of N,N-dimethylformamide and dimethylsulfoxide, and the volume ratio of N,N-dimethylformamide and dimethylsulfoxide in the mixed solvent is (3-5 ): 1, preferably 4:1.

In step S3, the temperature of the annealing treatment is 80° C.˜100° C., and the time is 5 min˜10 min. After the perovskite precursor solution is formed on the substrate, annealing is performed to crystallize the perovskite precursor solution to obtain a perovskite thin film. Considering the requirement of sufficient and complete crystallization, the preferred temperature is 100°C, and the preferred time is 10 min.

The illumination treatment is to use ultraviolet, infrared or sunlight irradiation, and the time is 5min-30min. The perovskite film crystallized after the annealing treatment is further subjected to light treatment, so that the acrylate in the perovskite film undergoes in-situ polymerization to generate a stable polymer. Considering that sunlight is easy to obtain and the acrylate needs to be fully polymerized, the sunlight is preferably sunlight, and the time is 10 min.

The acrylate is one or more of methyl methacrylate, ethyl methacrylate and ethyl cyanoacrylate, preferably ethyl cyanoacrylate. The in-situ reaction equation of the ethyl cyanoacrylate is as follows:

In the above-mentioned preparation method of the perovskite thin film, the acrylate monomer in the perovskite precursor solution can spontaneously undergo a polymerization reaction under the action of light to obtain a polymer. The reaction step is simple and easy to implement, no other reaction conditions are required, and it is easy to industrialize.

During the reaction process, the acrylate contains C=O functional group and C=C functional group, wherein the C=O functional group and B ions (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) at the perovskite grain boundary through coordination A weak interaction occurs between the bit bonds, which passivate the grain boundary defects. At the same time, the coordination between C=O functional group and B (such as Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , etc.) can make the polymer effectively attach to the grain boundary. After light treatment, the C=C functional group in the acrylate A polymerization reaction occurs, thereby forming a dense protective layer at the grain boundary, blocking the decomposition of water, oxygen and external factors on the perovskite, and improving the stability of the perovskite film.

The present invention also provides a perovskite solar cell, comprising a stacked hole transport layer 2, a perovskite thin film 3 and an electron transport layer 4, wherein the perovskite thin film 3 comprises a perovskite type ABX ₃ organic- Inorganic hybrid materials and polymers obtained by polymerizing acrylate monomers.

The perovskite battery further includes a substrate 1 and an electrode 5 .

Specifically, as shown in FIG. 4 , the perovskite solar cell includes a substrate 1 , a hole transport layer 2 , a perovskite film 3 , an electron transport layer 4 and an electrode 5 that are stacked in sequence.

The material of the substrate 1 is not limited, and can be any one of silicon wafer, glass, and stainless steel wafer. Since ITO is a metal compound with good transparent and conductive properties, and has characteristics such as band gap, high light transmittance in the visible spectral region, and low resistivity, the substrate 1 is preferably ITO conductive glass.

The hole transport layer 2 is a poly[3-(methylamine butyrate)thiophene] (PSCT-N) material layer with a thickness of 5nm to 20nm. Compared with the commonly used hole transport layer PEDOT:PSS (energy level 5.11 eV), the energy level of P3CT-N is 5.26eV, which is closer to the valence band (5.3eV) of the selected perovskite CH ₃ NH ₃ PbI ₃ , which can effectively avoid the decrease of cell efficiency due to energy level mismatch. . The preferred thickness of P3CT-N is 10 nm. The chemical structural formula of the P3CT-N is as follows:

The thickness of the perovskite thin film 3 is 400 nm˜500 nm. In consideration of balanced transport of carriers, the thickness is preferably 450 nm.

The electron transport layer 4 includes a PCBM layer, a C60 layer and a BCP layer that are stacked in sequence. The thickness of the PCBM layer is 20 nm to 50 nm, the thickness of the C60 layer is 20 nm to 40 nm, and the thickness of the BCP layer is 8 nm˜10 nm, and the thickness of the electron transport layer 4 is 50 nm˜100 nm. PCBM is prepared by solution spin coating, which can effectively penetrate and cover possible voids on the surface of perovskite, with a preferred thickness of 20 nm; while C60 is prepared by vacuum evaporation, so that the obtained C60 layer is more dense and uniform, with a preferred thickness of 40 nm; As a hole blocking layer, BCP can inhibit the recombination at the electrode interface and improve the device performance, and the preferred thickness is 8 nm.

The thickness of the electrode 5 is 100 nm to 300 nm, and the material of the electrode 5 is not limited, but considering that gold as an electrode is expensive and silver as an electrode has a short service life, the electrode 5 is preferably a copper electrode.

The above perovskite films are uniform and dense, without obvious voids, and the perovskite films have excellent stability. Therefore, perovskite solar cells using the above perovskite thin films not only have high conversion efficiency, but also have good stability.

The invention also provides a preparation method of the perovskite solar cell. The preparation method comprises the following steps:

providing a substrate 1;

forming a hole transport layer 2 on the substrate 1; and

A perovskite thin film 3 is formed on the hole transport layer 2 by using the above-mentioned preparation method of the perovskite thin film; and

forming an electron transport layer 4 on the perovskite thin film 3; and

An electrode 5 is formed on the electron transport layer 4 .

Described substrate 1 is ITO conductive glass, described ITO conductive glass is first washed with ITO cleaning agent and deionized water to remove grease and organic matter, then ultrasonically washed with deionized water, acetone, isopropanol successively, and dried with nitrogen, It is further processed by oxygen plasma.

The hole transport layer 2 is a P3CT-N material layer. The P3CT-N material layer is formed by spin coating with a P3CT-N solution. The P3CT-N solution is a methanol solution of P3CT-N, and the concentration of the P3CT-N is 1 mg/mL to 5 mg/mL.

The electron transport layer 4 includes a PCBM layer, a C60 layer and a BCP layer which are stacked in sequence. The PCBM layer is formed by spin coating of the PCBM solution, the rotation speed is 1500 rpm to 2500 rpm, and the time is 50 seconds to 80 seconds. The PCBM solution is a chlorobenzene solution of PCBM, and the concentration of the PCBM is 10 mg/mL to 25 mg/mL. The C60 layer and the BCP layer are formed by vacuum thermal evaporation.

The electrode 5 is a copper electrode, which is formed by vacuum thermal evaporation.

The above-mentioned preparation method of the perovskite solar cell has the advantages of being simple and easy to operate. The obtained perovskite solar cells have high conversion efficiency and good stability.

Hereinafter, the perovskite thin film, the perovskite solar cell and the preparation method thereof will be further described by the following specific examples.

Example 1:

PbI ₂ (668.5 mg) and CH ₃ NH ₃ I (230.5 mg) in a molar ratio of 1:1 and 5 mg of ethyl cyanoacrylate were dissolved in 1 mL of N,N-dimethylformamide in a 4:1 volume ratio and dimethyl sulfoxide mixed solvent to obtain a perovskite precursor solution. The concentrations of PbI ₂ and CH ₃ NH ₃ I were both 1.45 mmol/mL, and the concentration of ethyl cyanoacrylate was 5 mg/mL.

Then, the perovskite precursor solution was spin-coated on the ITO glass substrate with a spin coater at 4800 rpm for 20 s.

Then annealed at 100 °C for 10 minutes to form a perovskite thin film. After the formation of the perovskite film, the polymerization was carried out by solar irradiation, and the irradiation time was 10 minutes.

The obtained perovskite film includes a polymer of CH ₃ NH ₃ PbI ₃ and ethyl cyanoacrylate, wherein the mass percentage of the polymer of ethyl cyanoacrylate is 0.5%.

The infrared spectra of the perovskite films before and after light treatment are shown in Figure 1. It can be seen from Figure 1 that ethyl cyanoacrylate does exist in the perovskite film before light treatment. After light treatment, the carbon-carbon double bond peaks in the perovskite film disappeared, indicating that ethyl cyanoacrylate was completely polymerized to form a polymer.

Example 2:

PbI ₂ (668.5 mg) and CH ₃ NH ₃ I (230.5 mg) in a molar ratio of 1:1 and 3 mg of ethyl cyanoacrylate were dissolved in 1 mL of N,N-dimethylformamide in a 4:1 volume ratio and dimethyl sulfoxide mixed solvent to obtain a perovskite precursor solution. The concentrations of PbI ₂ and CH ₃ NH ₃ I were both 1.45 mmol/mL, and the concentration of ethyl cyanoacrylate was 3 mg/mL.

Then, the perovskite precursor solution was spin-coated on the ITO glass substrate with a spin coater at 4800 rpm for 20 s.

Then annealed at 100 °C for 5 minutes to form a perovskite thin film. After the perovskite film is formed, the ethyl cyanoacrylate is polymerized by solar irradiation, and the irradiation time is 30 minutes.

The obtained perovskite film includes a polymer of CH ₃ NH ₃ PbI ₃ and ethyl cyanoacrylate, wherein the mass percentage of the polymer of ethyl cyanoacrylate is 0.3%.

Example 3:

PbI ₂ (668.5 mg) and CH ₃ NH ₃ I (184.4 mg) in a molar ratio of 1:0.8 and 10 mg of ethyl cyanoacrylate were dissolved in 1 mL of N,N-dimethylformamide in a 3:1 volume ratio and dimethyl sulfoxide mixed solvent to obtain a perovskite precursor solution. The concentrations of PbI ₂ and CH ₃ NH ₃ I were both 1.45 mmol/mL, and the concentration of ethyl cyanoacrylate was 10 mg/mL.

Then, the perovskite precursor solution was spin-coated on the ITO glass substrate with a spin coater at 4800 rpm for 20 s.

Then annealed at 80 °C for 8 minutes to form a perovskite thin film. After the formation of the perovskite film, the ethyl cyanoacrylate was polymerized by ultraviolet light irradiation treatment, and the irradiation time was 5 minutes.

The obtained perovskite film includes a polymer of CH ₃ NH ₃ PbI ₃ and ethyl cyanoacrylate, wherein the mass percentage of the polymer of ethyl cyanoacrylate is 1%.

Example 4:

PbI ₂ (668.5 mg) and CH ₃ NH ₃ I (276.6 mg) in a molar ratio of 1:1.2 and 20 mg of ethyl cyanoacrylate were dissolved in 1 mL of N,N-dimethylformamide in a 5:1 volume ratio and dimethyl sulfoxide mixed solvent to obtain a perovskite precursor solution. The concentrations of PbI ₂ and CH ₃ NH ₃ I were both 1.45 mmol/mL, and the concentration of ethyl cyanoacrylate was 20 mg/mL.

Then, the perovskite precursor solution was spin-coated on the ITO glass substrate with a spin coater at 4800 rpm for 20 s.

Then annealed at 90 °C for 10 minutes to form a perovskite thin film. After the formation of the perovskite film, the ethyl cyanoacrylate was polymerized by irradiation with an infrared lamp, and the irradiation time was 20 minutes.

The obtained perovskite thin film includes a polymer of CH ₃ NH ₃ PbI ₃ and ethyl cyanoacrylate, wherein the mass percentage of the polymer of ethyl cyanoacrylate is 2%.

Example 5:

PbI ₂ (668.5 mg) and CH ₃ NH ₃ I (230.5 mg) in a molar ratio of 1:1 and 5 mg of methyl methacrylate were dissolved in 1 mL of N,N-dimethylformamide in a 4:1 volume ratio and dimethyl sulfoxide mixed solvent to obtain a perovskite precursor solution. The concentrations of PbI ₂ and CH ₃ NH ₃ I were both 1.45 mmol/mL, and the concentration of methyl methacrylate was 5 mg/mL.

Then, the perovskite precursor solution was spin-coated on the ITO glass substrate with a spin coater at 4800 rpm for 20 s.

Then annealed at 80 °C for 5 minutes to form a perovskite thin film. After the formation of the perovskite film, the methyl methacrylate was polymerized by ultraviolet light irradiation, and the irradiation time was 20 minutes.

The obtained perovskite film includes a polymer of CH ₃ NH ₃ PbI ₃ and methyl methacrylate, wherein the mass percentage of the polymer of methyl methacrylate is 0.5%.

Example 6

PbI ₂ (668.5 mg) and CH ₃ NH ₃ I (230.5 mg) in a molar ratio of 1:1 and 5 mg of ethyl methacrylate were dissolved in 1 mL of N,N-dimethylformamide in a 4:1 volume ratio and dimethyl sulfoxide mixed solvent to obtain a perovskite precursor solution. The concentrations of PbI ₂ and CH ₃ NH ₃ I were both 1.45 mmol/mL, and the concentration of ethyl methacrylate was 5 mg/mL.

Then, the perovskite precursor solution was spin-coated on the ITO glass substrate with a spin coater at 4800 rpm for 20 s.

Then annealed at 80 °C for 5 minutes to form a perovskite thin film. After the formation of the perovskite film, the ethyl methacrylate was polymerized by ultraviolet light irradiation, and the irradiation time was 20 minutes.

The obtained perovskite film includes a polymer of CH ₃ NH ₃ PbI ₃ and ethyl methacrylate, wherein the mass percentage of the polymer of ethyl methacrylate is 0.5%.

Example 7:

As shown in Figure 6, the perovskite solar cell includes a substrate 1, a hole transport layer 2, a perovskite thin film 3, an electron transport layer 4 and an electrode 5 that are stacked in sequence. The preparation method is as follows:

Using ITO conductive glass as substrate 1, first wash with ITO cleaning agent and deionized water to remove grease and organic matter, then ultrasonically wash with deionized water, acetone, and isopropanol in turn, dry with nitrogen, and then further process by oxygen plasma .

The hole transport layer 2 is fabricated on the treated ITO conductive glass by spin coating. The hole transport layer 2 is a P3CT-N material layer, which is formed by spin coating with a methanol solution of P3CT-N with a concentration of 2 mg/mL.

A perovskite thin film 3 with a thickness of 450 nm was fabricated on the hole transport layer 2 by using the preparation method of Example 1.

The electron transport layer 4 is made on the perovskite film 3, and a PCBM layer is formed by spin coating with a chlorobenzene solution of PCBM with a concentration of 10 mg/mL. is 20nm. Then, a C60 layer with a thickness of 40 nm is formed on the PCBM layer by vacuum thermal evaporation, and a BCP layer with a thickness of 8 nm is formed on the C60 layer by vacuum thermal evaporation.

On the electron transport layer 4, a layer of copper is evaporated to serve as the electrode 5 by vacuum thermal evaporation, and the thickness is 300 nm.

Example 8:

As shown in Figure 6, the perovskite solar cell includes a substrate 1, a hole transport layer 2, a perovskite thin film 3, an electron transport layer 4 and an electrode 5 that are stacked in sequence. The preparation method is as follows:

Using ITO conductive glass as substrate 1, first wash with ITO cleaning agent and deionized water to remove grease and organic matter, then ultrasonically wash with deionized water, acetone, and isopropanol in turn, dry with nitrogen, and then further process by oxygen plasma .

The hole transport layer 2 is fabricated on the treated ITO conductive glass by spin coating. The hole transport layer 2 is a P3CT-N material layer, which is formed by spin coating with a methanol solution of P3CT-N with a concentration of 1 mg/mL. 5nm.

A perovskite thin film 3 with a thickness of 400 nm was fabricated on the hole transport layer 2 by using the preparation method of Example 1.

The electron transport layer 4 is made on the perovskite film 3. First, a PCBM layer is formed by spin coating with a chlorobenzene solution of PCBM with a concentration of 15 mg/mL. is 30nm. Then, a C60 layer with a thickness of 20 nm is formed on the PCBM layer by vacuum thermal evaporation, and a BCP layer with a thickness of 10 nm is formed on the C60 layer by vacuum thermal evaporation.

On the electron transport layer 4, a layer of copper is deposited as the electrode 5 by vacuum thermal evaporation, and the thickness is 100 nm.

Example 9:

As shown in Figure 6, the perovskite solar cell includes a substrate 1, a hole transport layer 2, a perovskite thin film 3, an electron transport layer 4 and an electrode 5 that are stacked in sequence. The preparation method is as follows:

Using ITO conductive glass as substrate 1, first wash with ITO cleaning agent and deionized water to remove grease and organic matter, then ultrasonically wash with deionized water, acetone, and isopropanol in turn, dry with nitrogen, and then further process by oxygen plasma .

The hole transport layer 2 is fabricated on the treated ITO conductive glass by spin coating. The hole transport layer 2 is a P3CT-N material layer, which is formed by spin coating with a methanol solution of P3CT-N with a concentration of 3 mg/mL.

A perovskite thin film 3 with a thickness of 460 nm was fabricated on the hole transport layer 2 by using the preparation method of Example 1.

The electron transport layer 4 is made on the perovskite film 3, and a PCBM layer is formed by spin coating with a chlorobenzene solution of PCBM with a concentration of 18 mg/mL. is 40nm. Then, a C60 layer with a thickness of 30 nm is formed on the PCBM layer by vacuum thermal evaporation, and a BCP layer with a thickness of 9 nm is formed on the C60 layer by vacuum thermal evaporation.

On the electron transport layer 4, a layer of copper was deposited as the electrode 5 by vacuum thermal evaporation with a thickness of 200 nm.

Example 10:

As shown in Figure 6, the perovskite solar cell includes a substrate 1, a hole transport layer 2, a perovskite thin film 3, an electron transport layer 4 and an electrode 5 that are stacked in sequence. The preparation method is as follows:

Using ITO conductive glass as substrate 1, first wash with ITO cleaning agent and deionized water to remove grease and organic matter, then ultrasonically wash with deionized water, acetone, and isopropanol in turn, dry with nitrogen, and then further process by oxygen plasma .

The hole transport layer 2 is fabricated on the treated ITO conductive glass by spin coating. The hole transport layer 2 is a P3CT-N material layer, which is formed by spin coating with a methanol solution of P3CT-N with a concentration of 5 mg/mL.

A perovskite thin film 3 with a thickness of 500 nm was fabricated on the hole transport layer 2 by using the preparation method of Example 1.

The electron transport layer 4 is made on the perovskite film 3, and a PCBM layer is formed by spin coating with a chlorobenzene solution of PCBM with a concentration of 25 mg/mL. is 50nm. Then, a C60 layer with a thickness of 40 nm is formed on the PCBM layer by vacuum thermal evaporation, and a BCP layer with a thickness of 10 nm is formed on the C60 layer by vacuum thermal evaporation.

On the electron transport layer 4, a layer of copper is deposited as the electrode 5 by vacuum thermal evaporation with a thickness of 150 nm.

Comparative Example 1:

Comparative Example 1 has the same conditions as Example 1, except that the perovskite precursor solution of Comparative Example 1 does not contain ethyl cyanoacrylate, and the obtained perovskite film does not contain ethyl cyanoacrylate polymer .

Fig. 2 is the scanning electron microscope images of the perovskite films of Example 1 and Comparative Example 1 of the present invention. It can be seen from Fig. 2 that the addition of ethyl cyanoacrylate can effectively induce the uniform growth of perovskite, forming dense and uniform perovskite Mineral film. The crystal size of the perovskite thin film obtained in Example 1 is uniform, and the film is dense and uniform, without obvious voids or cracks; while the perovskite thin film obtained in Comparative Example 1 has different crystal sizes and obvious voids.

3 is a steady-state fluorescence spectrum diagram of the perovskite thin films of Example 1 and Comparative Example 1 of the present invention. It can be seen from Figure 3 that the addition of ethyl cyanoacrylate can blue-shift the fluorescence spectrum of the perovskite film, indicating that the defects inside the perovskite are effectively suppressed.

4 is a time-resolved fluorescence spectrogram of the perovskite thin films of Example 1 and Comparative Example 1 of the present invention. Time-resolved fluorescence spectroscopy shows that the addition of ethyl cyanoacrylate can effectively improve the lifetime of carriers in the perovskite film, and then the perovskite film can improve the cell efficiency when applied in perovskite solar cells.

5 is a comparison diagram of the X-ray diffraction (XRD) patterns of the perovskite thin films of Example 1 and Comparative Example 1 of the present invention. It can be seen from Figure 5 that the diffraction peak of the perovskite film containing ethyl cyanoacrylate does not shift, indicating that the addition of ethyl cyanoacrylate does not enter the perovskite crystal structure, but only exists near the grain boundary between its crystals.

Comparative Example 2:

The conditions of Comparative Example 2 are the same as those of Example 7, except that the perovskite film of Comparative Example 2 adopts the perovskite film obtained in Comparative Example 1, and the perovskite film does not contain a polymer of ethyl cyanoacrylate.

The efficiency comparison of the perovskite solar cell device of Example 7 and Comparative Example 2 is shown in Table 1.

Table 1

FIG. 7 is a comparison diagram of the stability of the perovskite solar cells in the air of Example 7 and Comparative Example 2 of the present invention, and the air humidity is: 40% to 60%. It can be seen from FIG. 7 that the stability of the perovskite solar cell of the present invention is significantly improved.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims (8)

1. a preparation method of perovskite film, is characterized in that, described preparation method comprises the following steps: Dissolving acrylate monomers, AX and BX ₂ in a solvent to obtain a perovskite precursor solution; forming the perovskite precursor solution on a substrate; The substrate with the perovskite precursor solution is sequentially subjected to annealing treatment and light treatment to obtain a perovskite film; wherein, during the light treatment process, the acrylate monomer undergoes a polymerization reaction to form a polymer, and the perovskite The mass percentage of the polymer in the film is 0.3% to 2%. 2. the preparation method of perovskite film according to claim 1, is characterized in that, A in described AX is organic amine cation, X is halogen anion or SCN- ^; B in described BX ₂ is Pb ² Any of ⁺ , Sn ²⁺ , and Ge ²⁺ . 3. the preparation method of perovskite film according to claim 1, is characterized in that, described acrylate monomer is a kind of in methyl methacrylate, ethyl methacrylate, ethyl cyanoacrylate or variety. 4. The preparation method of the perovskite film according to claim 1, wherein the temperature of the annealing treatment is 80°C to 100°C, and the time is 5min to 10min. 5. the preparation method of perovskite film according to claim 1, is characterized in that, described illumination treatment adopts ultraviolet, infrared or sunlight irradiation, and the time is 5min～30min. 6. A perovskite film, characterized in that, the perovskite film is prepared by the preparation method of the perovskite film according to any one of claims 1-5, and the perovskite film comprises calcium Titanite-type ABX ₃ organic-inorganic hybrid materials and polymers obtained by polymerizing acrylate monomers. 7. A perovskite solar cell, comprising a stacked hole transport layer, the perovskite thin film as claimed in claim 6 and an electron transport layer. 8. a preparation method of perovskite solar cell, is characterized in that, described preparation method comprises the following steps: providing a substrate; forming a hole transport layer on the substrate; and A perovskite film is formed on the hole transport layer using the preparation method according to any one of claims 1 to 5; and forming an electron transport layer on the perovskite film; and An electrode is formed on the electron transport layer.

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