Transparent Perovskite Solar Cells with Double Hole Transport Layers and Their Preparation Methods

Abstract

The present invention discloses a tandem hole transport layer perovskite solar cell, where the hole transport layer is composed of a first hole transport layer PTAA and a second hole transport layer PEDOT:PSS, and the second hole transport layer is disposed between the first hole transport layer and the perovskite light absorption layer; based on the single layer, the present invention improves the transport ability of the hole transport layer and the compactness of the perovskite layer, thereby enhancing the performance of the battery. Compared with the traditional tandem hole transport layer perovskite solar cell with a single layer hole transport layer, the structure with a tandem hole transport layer can effectively improve the transport ability of the hole transport layer and the compactness of the perovskite layer, which greatly enhances the performance of the entire battery device and provides a new idea for the future development direction of perovskite solar cells.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and particularly relates to a reverse perovskite solar cell with a double-layer hole transport layer and a preparation method thereof. Background Art

[0002] In recent years, reverse-structure perovskite solar cells have attracted increasing attention due to their easy fabrication, cost-effectiveness, and hysteresis suppression characteristics. In reverse perovskite cells, PTAA, which has advantages such as high carrier mobility, good stability, and good energy level alignment with perovskite, has become the most widely used hole transport layer material. However, PTAA is a typical hydrophobic polymer, and there are no suitable groups on its surface for binding perovskite, resulting in very few perovskite growth sites on it. The inappropriate interfacial contact between PTAA and perovskite leads to many holes in the perovskite film, significantly affecting the photovoltaic properties of perovskite. Currently, the most commonly used method to improve the hydrophobicity of PTAA is to rinse PTAA with DMF, but the introduction of a hydrophilic interlayer not only makes the structure of the solar cell more complex but also increases the possibility of carrier recombination at the interface. Summary of the Invention

[0003] The purpose of the present invention is to provide a reverse perovskite solar cell with a double-layer hole transport layer and a preparation method thereof, and to improve the transport ability of the hole transport layer and the compactness of the perovskite layer through the double-layer hole transport layer structure, so as to obtain better battery performance.

[0004] To achieve the above purpose, the following technical solutions are adopted:

[0005] A reverse perovskite solar cell with a double-layer hole transport layer is composed of the following structure: an ITO conductive glass substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode; wherein, the hole transport layer is composed of a first hole transport layer PTAA and a second hole transport layer PEDOT:PSS, and the second hole transport layer is disposed between the first hole transport layer and the perovskite light-absorbing layer.

[0006] The preparation method of the above-mentioned reverse perovskite solar cell with a double-layer hole transport layer includes the following steps:

[0007] S1. Cleaning of the ITO conductive glass substrate: The glass substrate is cleaned successively with a variety of solutions, and after drying, it is cleaned with an ultraviolet ozone cleaner;

[0008] S2. Preparation of the first hole transport layer: The prepared PTAA solution is spin-coated on the conductive glass substrate by spin coating to prepare the first hole transport layer, and annealing is performed after spin coating;

[0009] S3. Preparation of the second hole transport layer: Spin-coat the prepared PEDOT:PSS solution on the first hole transport layer to prepare the second hole transport layer, and anneal after spin-coating.

[0010] S4. Preparation of the perovskite light-absorbing layer: Spin-coat the prepared perovskite solution on the second hole transport layer, and anneal after spin-coating.

[0011] S5. Preparation of the electron transport layer: Spin-coat the prepared PCBM solution on the perovskite light-absorbing layer, and anneal after spin-coating; Transfer the substrate covered with the PCBM thin film to an evaporation apparatus, and evacuate to a working pressure below 9×10 -4 Pa, heat the evaporation source carrying BCP by evaporation method to deposit the electron transport layer.

[0012] S6. Preparation of the metal electrode: Place the substrate after depositing the electron transport layer in another chamber of the evaporation apparatus, and evacuate to a working pressure below 6.5×10 -4 Pa, heat the evaporation source carrying silver by evaporation method to deposit the metal electrode.

[0013] According to the above scheme, the specific cleaning process in S1 is as follows:

[0014] At room temperature of 18 - 28°C, rinse both sides of the ITO conductive glass substrate with tap water, wipe the surface of the transparent conductive substrate repeatedly 3 times with a dust-free cloth dipped in dishwashing liquid, then place it in a mixed solution of 3 mL of dishwashing liquid and 40 mL of tap water, and ultrasonically clean for 30 minutes.

[0015] At room temperature of 18 - 28°C, rinse both sides of the glass thoroughly with sufficient deionized water, place the transparent conductive substrate in 40 mL of deionized water and ultrasonically clean for 30 minutes to ensure sufficient dissolution and removal of residual impurities on the surface.

[0016] At room temperature of 18 - 28°C, place the conductive substrate in ethanol and ultrasonically clean for 30 minutes to remove some residual organic impurities on the surface, then dry the liquid on the surface with a dry nitrogen pump in the air, and dry it to obtain a clean ITO glass substrate.

[0017] At room temperature of 18 - 28°C, place the dried ITO glass substrate with the ITO side facing up in the carrier tray of the ultraviolet cleaning machine, start ultraviolet treatment for 10 - 15 minutes to ensure that the ultraviolet light and the generated ozone can fully soften and react to remove the organic impurities on the substrate surface.

[0018] According to the above scheme, the PTAA solution in S2 is prepared by dissolving PTAA powder in chlorobenzene. The spin-coating solution volume is 30 μL, the spin-coating speed is 6000 revolutions per second, and the duration is 30 seconds; The annealing process anneals the substrate at 150°C for 10 minutes.

[0019] According to the above scheme, the PEDOT:PSS solution in S3 is prepared by doping the PEDOT:PSS aqueous solution into anhydrous methanol. The spin-coated solution volume is 35 μL, the spin-coating speed is 5000 revolutions per second, and the duration is 30 seconds; during the annealing process, the substrate is annealed at 150 °C for 20 minutes.

[0020] According to the above scheme, the perovskite solution in S4 is prepared by dissolving PbI2, FAI, PbBr2, MABr, and CsI in a mixed solution of DMF and DMSO with a volume ratio of 4:1 in a certain proportion, adding a certain amount of CsI, and oscillating with an oscillator at a frequency of 2000 times per minute for 15 - 30 minutes; the spin-coating speed is 6000 revolutions per second, and the duration is 30 seconds; during the annealing process, the substrate is annealed at 120 °C for 45 minutes.

[0021] According to the above scheme, the PCBM solution in S5 is prepared by dissolving PCBM powder in chlorobenzene. The spin-coated solution volume is 35 μL, the spin-coating speed is 4000 revolutions per second, and the duration is 30 seconds; during the annealing process, the substrate is annealed at 70 °C for 20 minutes; the evaporation rate of BCP is controlled at 0.8 - 1.2 nm / s, and the BCP thin film thickness is 6.8 - 7.2 nm.

[0022] According to the above scheme, the evaporation rate of silver in S6 is controlled at 0.8 - 1.2 nm / s, and the silver thin film thickness is 90 - 110 nm.

[0023] Compared with the existing technology, the advantages of the present invention are as follows:

[0024] Inappropriate interfacial contact between PTAA and perovskite leads to more holes in the perovskite thin film, significantly affecting the photovoltaic properties of perovskite. PEDOT:PSS is also an excellent hole transport layer material with better interfacial contact with perovskite, so it can be used for interfacial modification of PTAA and reduce the possibility of carrier interfacial recombination. On the basis of the single layer, the present invention's double-layer hole transport layer improves the transport ability of the hole transport layer and the compactness of the perovskite layer, thereby enhancing the performance of the battery.

[0025] Compared with traditional inverted perovskite solar cells with a single-layer hole transport layer, adopting a double-layer hole transport layer structure can effectively improve the transport ability of the hole transport layer and the compactness of the perovskite layer, which greatly enhances the performance of the entire battery device and provides a new idea for the future development direction of perovskite solar cells. Brief Description of the Drawings

[0026] Figure 1 : Schematic diagram of the structure of the inverted perovskite solar cell of the present invention;

[0027] Figure 2 : Cross-sectional SEM image of the perovskite solar cell of the present invention;

[0028] Figure 3 : J-V curve of the perovskite solar cell of Example 1;

[0029] Figure 4 : J-V curve of the perovskite solar cell of Example 2;

[0030] Figure 5 : J-V curve of the perovskite solar cell of Example 3;

[0031] Figure 6 : J-V curve of the perovskite solar cell of Example 4. Detailed implementation manners

[0032] The technical solution of the present invention will be further described in detail below in combination with specific implementation examples, so that those skilled in the art can better understand the present invention. However, the protection scope of the present invention is not limited to the following examples, and the scope of rights of the present invention shall be defined by the claims.

[0033] The present invention aims to improve the inappropriate interfacial contact between PTAA and perovskite, and provides a perovskite solar cell with a double-layer hole transport layer. Referring to the attached Figure 1 as shown: It is composed of an ITO conductive glass substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a metal electrode; wherein, the hole transport layer is composed of a first hole transport layer PTAA and a second hole transport layer PEDOT:PSS, and the second hole transport layer is arranged between the first hole transport layer and the perovskite light absorption layer. Figure 2 is the cross-sectional SEM image of the perovskite solar cell prepared by the present invention. It can be seen from the figure that there are obvious layers, corresponding from bottom to top to the Figure 1 structural diagram.

[0034] A perovskite solar cell with a double-layer hole transport layer is composed of the following structures: an ITO conductive glass substrate, a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a metal electrode; wherein, the hole transport layer is composed of a first hole transport layer PTAA and a second hole transport layer PEDOT:PSS, and the second hole transport layer is arranged between the first hole transport layer and the perovskite light absorption layer.

[0035] The preparation process of the perovskite solar cell with a double-layer hole transport layer of the present invention is as follows:

[0036] S1. Cleaning of the ITO conductive glass substrate:

[0037] At room temperature of 18 - 28 °C, rinse both sides of the ITO conductive glass substrate with tap water, wipe the surface of the transparent conductive substrate repeatedly 3 times with a dust-free cloth dipped in dishwashing liquid, and then place it in a mixed solution of 3 mL of dishwashing liquid and 40 mL of tap water for ultrasonic cleaning for 30 minutes;

[0038] At room temperature of 18 - 28 °C, rinse both sides of the glass thoroughly with sufficient deionized water, place the transparent conductive substrate in 40 mL of deionized water for ultrasonic treatment for 30 minutes to ensure sufficient dissolution and removal of residual impurities on the surface;

[0039] At room temperature of 18 - 28 °C, place the conductive substrate in ethanol for ultrasonic cleaning for 30 minutes to remove some residual organic impurities on the surface, and then dry the liquid on the surface with a dry nitrogen pump in the air. After drying, a clean ITO glass substrate can be obtained;

[0040] At room temperature of 18 - 28 °C, place the dried ITO glass substrate with the ITO side facing up in the loading tray of the ultraviolet cleaner, start the ultraviolet treatment for 10 - 15 minutes to ensure that the ultraviolet rays and the generated ozone can fully soften and react to remove the organic impurities on the surface of the substrate.

[0041] S2. Preparation of the first hole transport layer:

[0042] Use the spin-coating method to spin-coat the prepared PTAA solution on the conductive glass substrate to prepare the first hole transport layer, and anneal after spin-coating; the PTAA solution is prepared by dissolving PTAA powder in chlorobenzene. The spin-coating solution is measured as 30 μL, the spin-coating speed is 6000 revolutions per second, and the duration is 30 seconds; the annealing process anneals the substrate at 150 °C for 10 minutes.

[0043] S3. Preparation of the second hole transport layer:

[0044] Use the spin-coating method to spin-coat the prepared PEDOT:PSS solution on the first hole transport layer to prepare the second hole transport layer, and anneal after spin-coating; the PEDOT:PSS solution is prepared by doping PEDOT:PSS aqueous solution in anhydrous methanol. The spin-coating solution is measured as 35 μL, the spin-coating speed is 5000 revolutions per second, and the duration is 30 seconds; the annealing process anneals the substrate at 150 °C for 20 minutes.

[0045] S4. Preparation of perovskite light-absorbing layer: Spin-coat the prepared perovskite solution on the second hole transport layer and anneal it after spin-coating; the perovskite solution is prepared by dissolving PbI2, FAI, PbBr2, MABr, and CsI in a mixed solution of DMF and DMSO with a volume ratio of 4:1, adding a certain amount of CsI, and oscillating it with an oscillator at a frequency of 2000 times per minute for 15 - 30 minutes; the spin-coating speed is 6000 revolutions per second and the duration is 30 seconds; the annealing process anneals the substrate at 120 °C for 45 minutes.

[0046] S5. Preparation of electron transport layer: Spin-coat the prepared PCBM solution on the perovskite light-absorbing layer and anneal it after spin-coating; transfer the substrate coated with the PCBM thin film to an evaporation coater and evacuate it to a working pressure below 9×10 -4 Pa, heat the evaporation source carrying BCP by evaporation method to deposit the electron transport layer; the PCBM solution is prepared by dissolving PCBM powder in chlorobenzene, 35 μL of the spin-coating solution is measured, the spin-coating speed is 4000 revolutions per second, and the duration is 30 seconds; the annealing process anneals the substrate at 70 °C for 20 minutes; the evaporation rate of BCP is controlled at 0.8 - 1.2 nm / s, and the thickness of the BCP thin film is 6.8 - 7.2 nm.

[0047] S6. Preparation of metal electrode: Place the substrate after depositing the electron transport layer in another chamber of the evaporation coater and evacuate it to a working pressure below 6.5×10 -4 Pa, heat the evaporation source carrying silver by evaporation method to deposit the metal electrode; the evaporation rate of silver is controlled at 0.8 - 1.2 nm / s, and the thickness of the silver thin film is 90 - 110 nm.

[0048] Example 1

[0049] A tandem perovskite solar cell with a bilayer hole transport layer and its preparation method, wherein the hole transport layer is composed of a first hole transport layer PTAA and a second hole transport layer PEDOT:PSS, and the specific preparation process is as follows:

[0050] (1) Cleaning and treatment of ITO transparent conductive substrate: First, clean the surface of the transparent conductive substrate with a dust-free cloth and dishwashing liquid, then place the transparent conductive substrate in a mixed solution of dishwashing liquid and deionized water and ultrasonically clean it for 30 minutes; then, after rinsing it clean with deionized water, place the transparent conductive substrate in deionized water and ultrasonically clean it for 30 minutes; finally, place the conductive substrate in ethanol and ultrasonically clean it for 30 minutes. After ultrasonic cleaning, dry it with dry nitrogen for standby. In an ozone atmosphere, use ultraviolet light to perform surface treatment on the cleaned and dried conductive substrate, and the treatment time is 10 - 15 minutes.

[0051] (2) Preparation of the first hole transport layer: Dissolve 2 mg of PTAA powder in 1 mL of chlorobenzene solution, and shake until evenly mixed. Use a pipette to transfer 35 μL of the filtered PTAA solution onto a transparent conductive glass substrate, and spin-coat to form a film under the program of a rotation speed of 6000 revolutions per second for 30 seconds. Then anneal the substrate at 150 °C for 10 minutes to form a dense hole transport layer.

[0052] (3) Preparation of the second hole transport layer: Mix PEDOT:PSS solution and anhydrous methanol in a ratio of 1:10, and shake until uniform. Use a pipette to transfer 35 μL of the mixed PEDOT:PSS solution onto a transparent conductive glass substrate, and spin-coat to form a film under the program of a rotation speed of 5000 revolutions per second for 30 seconds. Then anneal the substrate at 150 °C for 20 minutes to form a dense hole transport layer.

[0053] (4) Preparation of the perovskite light-absorbing layer: Weigh 548.6 mg of PbI2, 190.06 mg of FAI, 77.07 mg of PbBr2, and 21.84 mg of MABr. Dissolve PbI2, FAI, PbBr2, and MABr in a mixed solution of 640 μL of DMF and 160 μL of DMSO, and add 30 μL of CsI to obtain a perovskite precursor solution. Shake and filter it, and then spin-coat the precursor solution evenly on the annealed hole transport layer by the spin-coating method at a rotation speed of 6000 revolutions per second for 30 seconds. Then anneal the substrate at 120 °C for 45 minutes.

[0054] (5) Preparation of the electron transport layer: Dissolve 20 mg of PCBM powder in 1 mL of chlorobenzene to obtain a PCBM solution. Then spin-coat the PCBM solution evenly on the annealed perovskite layer by the spin-coating method at a rotation speed of 4000 revolutions per second for 30 seconds. Then anneal the substrate at 70 °C for 20 minutes. Transfer the substrate coated with the PCBM thin film to an evaporation instrument, and evacuate to below 9×10 -4 Pa. Heat the evaporation source containing BCP to evaporate the material inside onto the surface of the BCPM thin film, and control the evaporation rate at 0.8 - 1.2 nm / s until the thickness of the BCP thin film reaches 6.8 - 7.2 nm.

[0055] (6) Preparation of the metal electrode: Place the substrate coated with the electron transport layer in another chamber of the evaporation instrument, and evacuate to a working pressure below 6.5×10 -4 Pa. Heat the evaporation source containing silver to evaporate the material inside onto the surface of the BCP film, and control the evaporation rate at 0.8 - 1.2 nm / s. After the thickness of the silver thin film reaches 100 nm, the coating is completed.

[0056] Example 2

[0057] In this embodiment, the hole transport layer is a bilayer structure of PTAA and PEDOT:PSS. The specific preparation steps of the hole transport layer are as follows:

[0058] Dissolve 2 mg of PTAA powder in 1 mL of chlorobenzene solution and shake until evenly mixed. Use a pipette to transfer 35 μL of the filtered PTAA solution onto a transparent conductive glass substrate, and spin-coat it into a film under the program of a rotation speed of 6000 revolutions per second for 30 seconds. Then anneal the substrate at 150 °C for 10 minutes to form a dense hole transport layer. Mix the PEDOT:PSS solution and anhydrous methanol in a ratio of 1:12 and shake until homogeneous. Use a pipette to transfer 35 μL of the mixed PEDOT:PSS solution onto a transparent conductive glass substrate, and spin-coat it into a film under the program of a rotation speed of 5000 revolutions per second for 30 seconds. Then anneal the substrate at 150 °C for 20 minutes to form a dense hole transport layer. The remaining steps are the same as those in Example 1.

[0059] Example 3

[0060] In this embodiment, the hole transport layer is a single layer of PTAA. The specific preparation steps of the hole transport layer are as follows:

[0061] Dissolve 2 mg of PTAA powder in 1 mL of chlorobenzene solution and shake until evenly mixed to obtain a PTAA solution. Filter the shaken PTAA solution in a glove box, use a pipette to transfer 35 μL of the filtered PTAA solution onto a transparent conductive glass substrate, and spin-coat it into a film under the program of a rotation speed of 6000 revolutions per second for 30 seconds. Then anneal the substrate at 150 °C for 10 minutes to form a dense hole transport layer. The remaining steps are the same as those in Example 1.

[0062] Example 4

[0063] In this embodiment, the hole transport layer is a single layer of PEDOT:PSS. The specific preparation steps of the hole transport layer are as follows:

[0064] Mix the PEDOT:PSS solution and anhydrous methanol in a ratio of 1:3 and shake until homogeneous. Use a pipette to transfer 35 μL of the mixed PEDOT:PSS solution onto a transparent conductive glass substrate, and spin-coat it into a film under the program of a rotation speed of 5000 revolutions per second for 30 seconds. Then anneal the substrate at 150 °C for 20 minutes to form a dense hole transport layer. The remaining steps are the same as those in Example 1.

[0065] After the batteries obtained in Examples 1, 2, 3, and 4 are assembled, the J-V curves of the batteries can be obtained by testing with computer software under standard 100% light intensity. Figures 3 - 6 They are the J-V curve graphs of the inverted perovskite solar cells prepared in Examples 1, 2, 3, and 4 respectively.

[0066] Table 1 shows the performance parameters of the inverted perovskite solar cells prepared in Examples 1, 2, 3, and 4.

[0067] Table 1

[0068] Voc (V) <![CDATA[Jsc (mA / cm 2 )]]> FF PCE (%) Example 1 0.905 17.90 0.80 12.92 Example 2 0.904 16.55 0.75 11.19 Example 3 1.030 21.12 0.51 11.02 Example 4 0.809 18.75 0.65 9.88

[0069] It can be seen from the comparison of the data in the accompanying drawings and Table 1 that, compared with the traditional single-layer hole transport layer, the fill factor, efficiency, etc. of the cells with a bilayer hole transport layer structure have increased significantly, and the cell performance has been improved.

[0070] For those of ordinary skill in the art, although the present invention presents specific implementation manners, for those of ordinary skill in the art, without departing from the spirit or basic characteristics of the present invention, the technical solutions in the embodiments can also be appropriately changed, modified, substituted, and deformed to form other implementation manners that can be understood by those skilled in the art. The protection scope of the present invention should be subject to the protection scope defined by the claims.

Claims

1. A preparation method of a perovskite solar cell with a double-layer hole transport layer, characterized in that It includes the following steps: S1. Cleaning of ITO conductive glass substrate: Clean the glass substrate successively with multiple solutions, and after drying, clean it with an ultraviolet ozone cleaner; S2. Preparation of the first hole transport layer: Spin-coat the prepared PTAA solution on the conductive glass substrate by spin coating to prepare the first hole transport layer, and anneal it after spin coating; the PTAA solution is prepared by dissolving PTAA powder in chlorobenzene; the annealing process anneals the substrate at 150 °C for 10 minutes; S3. Preparation of the second hole transport layer: Spin-coat the prepared PEDOT:PSS solution on the first hole transport layer by spin coating to prepare the second hole transport layer, and anneal it after spin coating; The PEDOT:PSS solution is prepared by doping the PEDOT:PSS aqueous solution in anhydrous methanol; the annealing process anneals the substrate at 150 °C for 20 minutes; S4. Preparation of the perovskite light-absorbing layer: Spin-coat the prepared perovskite solution on the second hole transport layer, and anneal it after spin coating; S5. Preparation of the electron transport layer: Spin-coat the prepared PCBM solution on the perovskite light-absorbing layer, and anneal it after spin coating; Transfer the substrate coated with the PCBM film to an evaporation apparatus and evacuate it to a working pressure below 9×10 -4 Pa. Heat the evaporation source carrying BCP by evaporation method to deposit the electron transport layer; S6. Preparation of metal electrode: Place the substrate with the electron transport layer evaporated thereon in another chamber of the evaporation apparatus, and evacuate to a working pressure of less than 6.5×10 -4 Pa, and use evaporation method to heat the evaporation source carrying silver to evaporate the metal electrode.

2. The preparation method of the inverted perovskite solar cell with a double-layer hole transport layer as described in claim 1, characterized in that The specific cleaning process in S1 is: At room temperature of 18 - 28 °C, rinse both sides of the ITO conductive glass substrate with tap water, wipe the surface of the transparent conductive substrate repeatedly 3 times with a dust-free cloth dipped in dishwashing liquid, and then place it in a mixed solution of 3 mL of dishwashing liquid and 40 mL of tap water for ultrasonic cleaning for 30 minutes; At room temperature of 18 - 28 °C, rinse both sides of the glass thoroughly with sufficient deionized water, place the transparent conductive substrate in 40 mL of deionized water for ultrasonic treatment for 30 minutes to ensure sufficient dissolution and removal of residual impurities on the surface; At room temperature of 18 - 28 °C, place the conductive substrate in ethanol for ultrasonic cleaning for 30 minutes to remove some residual organic impurities on the surface, and then dry the liquid on the surface with a dry nitrogen pump in the air. After drying, a clean ITO glass substrate can be obtained; At room temperature of 18 - 28 °C, place the dried ITO glass substrate with the ITO side facing up in the loading tray of the ultraviolet cleaner, and start ultraviolet treatment for 10 - 15 minutes to ensure that the ultraviolet rays and the generated ozone can fully soften and react to remove the organic impurities on the substrate surface.

3. The preparation method of the inverted perovskite solar cell with a double-layer hole transport layer as described in claim 1, characterized in that In S2, 30 μL of the spin-coated solution is taken, the spin-coating speed is 6000 revolutions per second, and the duration is 30 seconds.

4. The preparation method of the inverted perovskite solar cell with a double-layer hole transport layer as described in claim 1, characterized in that In S3, 35 μL of the spin-coated solution is taken, the spin-coating speed is 5000 revolutions per second, and the duration is 30 seconds.

5. The preparation method of the inverted perovskite solar cell with a double-layer hole transport layer as described in claim 1, characterized in that In S4, the perovskite solution is prepared by dissolving PbI2, FAI, PbBr2, MABr, CsI in a mixed solution of DMF and DMSO with a volume ratio of 4:1 in a certain proportion, adding a certain amount of CsI, and oscillating it with an oscillator at a frequency of 2000 times per minute for 15 - 30 minutes; the spin-coating speed is 6000 revolutions per second, and the duration is 30 seconds; the annealing process anneals the substrate at 120 °C for 45 minutes.

6. The preparation method of the inverted perovskite solar cell with a double-layer hole transport layer as described in claim 1, characterized in that The PCBM solution described in S5 is prepared by dissolving PCBM powder in chlorobenzene. 35 μL of the spin-coated solution is measured, the spin-coating speed is 4000 revolutions per second, and the duration is 30 seconds. During the annealing process, the substrate is annealed at 70 °C for 20 minutes. The evaporation rate of BCP is controlled at 0.8 - 1.2 nm / s, and the film thickness of the BCP film is 6.8 - 7.2 nm.

7. The preparation method of the inverted perovskite solar cell with a double-layer hole transport layer according to claim 1, characterized in that In S6, the evaporation rate of silver is controlled at 0.8 - 1.2 nm / s, and the film thickness of the silver film is 90 - 110 nm.

Images