Preparation method of transparent perovskite thin film with high fill factor

Abstract

The invention discloses a preparation method of a transparent perovskite thin film with a high fill factor, and relates to the technical field of perovskite solar cells. The preparation method comprises the following steps: placing a heated low-boiling-point solvent in spin-coating equipment, and enabling the spin-coating equipment to be filled with a steam atmosphere of the low-boiling-point solvent; preparing a perovskite solution based on CsI, PbBr2 and PbI2; and placing the electron transport layer substrate on a rotating platform of spin-coating equipment, spin-coating the electron transport layer substrate with the perovskite solution, and carrying out heating treatment to prepare the transparent perovskite thin film with the high fill factor. The perovskite thin film is prepared in the low-boiling-point solvent atmosphere, and the formed perovskite solar cell is larger in filling factor and better in charging performance. According to the invention, the heated low-boiling-point solvent is placed in the spin-coating equipment, so that compared with a method of directly mixing the low-boiling-point solvent with the perovskite solution, the formed perovskite film has higher light transmittance, and the fill factor of the solar cell is larger.

Description

Technical Field

[0001] The invention relates to the technical field of perovskite solar cells, and in particular to a method for preparing a transparent perovskite film with a high filling factor. Background Art

[0002] In the face of the demand for renewable energy, perovskite solar cells have become a hot spot for the research of next-generation photovoltaic technology with their advantages of low cost and high conversion efficiency. From a process perspective, in the production of perovskite cells, coating, laser etching, and packaging are the three core process links. The most core of these is the preparation of perovskite thin films. How to prepare uniform, hole-free perovskite thin films on large-area substrates is the key direction of technical research. At present, the preparation methods of perovskite thin films mainly include dry method and wet method. The dry method mainly uses vacuum evaporation equipment. Under a high vacuum environment, the organic and inorganic materials required for the perovskite layer are sublimated and deposited on the surface of the substrate by heating the evaporation source to form a thin film. Due to the consistent environment in the vacuum chamber, the uniformity of the deposited film and the consistency between batches are relatively easy to control, and the process controllability is high, but the disadvantage is that the process speed is slow. In order to achieve the same production rhythm, the equipment investment is relatively large. The so-called wet method, that is, the low-cost solution method, prepares the organic and inorganic materials required for the perovskite layer into a precursor solution, and forms a film and crystallizes through slit coating technology. The solution method is simple to operate and has a fast film-forming speed, but it requires the recovery and environmentally friendly treatment of organic solvents, which increases the investment in back-end auxiliary equipment.

[0003] Fill factor refers to the ratio of the maximum power of a solar cell to the product of its open circuit voltage and short circuit current. It is an important parameter for evaluating the output characteristics of a solar cell. The higher its value, the closer the output characteristics of the solar cell are to a rectangle, and the higher the photoelectric conversion efficiency. The fill factor mainly depends on the material properties of the solar cell itself, and is not strongly dependent on the light source used.

[0004] Chinese patent CN113611804A discloses a perovskite material solution, a perovskite film, and a preparation method and application thereof. The patent provides a method for preparing a perovskite film and a perovskite solar cell, in which the perovskite material is dissolved in a low-boiling point solvent of a mixed component. The low-boiling point solvent evaporates quickly and can promote the rapid crystallization of the perovskite material, so that no auxiliary method or equipment is required to promote the crystallization of the perovskite. Moreover, the quality of the formed perovskite crystals is better, with advantages such as high temperature resistance and good stability, and the stability of the formed perovskite solar cell has been greatly improved. However, mixing a low-boiling point solvent with a perovskite material solution will introduce impurities into the perovskite film, resulting in poor performance of the perovskite solar cell.

[0005] In view of this, in order to solve the deficiencies of the prior art, the present invention provides a method for preparing a transparent perovskite film with a high filling factor. The transparent perovskite film prepared by the present invention can be applied to perovskite solar cells and has a good industrial application prospect. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a transparent perovskite film with a high filling factor. The transparent perovskite film prepared by the present invention can be applied to perovskite solar cells, greatly improving the filling factor of perovskite solar cells and having good industrial application prospects.

[0007] To achieve the above-mentioned purpose of the invention, the technical solution of the present invention is as follows:

[0008] In one aspect, the present invention provides a method for preparing a transparent perovskite film with a high filling factor, comprising the following steps:

[0009] S1. placing a heated low-boiling-point solvent in a spin coating device so that the spin coating device is filled with a vapor atmosphere of the low-boiling-point solvent;

[0010] S2, based on CsI, PbBr 2 、PbI 2 preparing a perovskite solution;

[0011] S3. Place the electron transport layer substrate on a rotating platform of a spin coating device, spin coat the perovskite solution on the electron transport layer substrate, and obtain a transparent perovskite film with a high filling factor after heating treatment.

[0012] Preferably, in step S1, the low boiling point solvent is selected from at least one of methanol, ethanol, propanol, ethyl acetate, methyl ether, ethyl ether and propyl ether.

[0013] Further preferably, in step S1, the low boiling point solvent is selected from at least one of ethanol and ethyl acetate.

[0014] More preferably, in step S1, the low boiling point solvent is ethanol.

[0015] Preferably, in step S3, the electron transport layer substrate is selected from SnO 2 Substrate, TiO 2 Any of the bases.

[0016] Preferably, in step S2, the solvent of the perovskite solution is dimethyl sulfoxide.

[0017] Further preferably, in step S2, the concentration of CsI in the perovskite solution is 200-400 mg / mL; CsI, PbBr 2 、PbI 2The molar ratio is 1-4:1-2:1-2.

[0018] More preferably, in step S2, the concentration of CsI in the perovskite solution is 272 mg / mL; 2 、PbI 2 The molar ratio is 2.06:1:1.

[0019] Preferably, in step S3, the specific conditions of the heating treatment are: 140-180° C., 15-40 min.

[0020] Further preferably, in step S3, the specific conditions of the heating treatment are: 160° C., 20 min.

[0021] In another aspect, the present invention provides a perovskite solar cell, comprising a transparent perovskite film with a high filling factor prepared according to the above preparation method.

[0022] Preferably, the perovskite solar cell further comprises a hole layer and a silver electrode.

[0023] Further preferably, the cavity layer comprises poly-3-hexylthiophene and chlorobenzene.

[0024] In another aspect, the present invention provides the use of a transparent perovskite film with a high filling factor prepared according to the above preparation method in a solar cell.

[0025] The beneficial effects of the present invention are:

[0026] (1) The present invention provides a method for preparing a transparent perovskite film with a high filling factor. The perovskite film is prepared in a low-boiling point solvent atmosphere. The formed perovskite solar cell has a larger filling factor and better charging performance.

[0027] (2) The present invention limits the method of introducing the low-boiling point solvent, and places the heated low-boiling point solvent in the spin coating device. Compared with directly mixing the low-boiling point solvent with the perovskite solution, the transmittance of the formed perovskite film is higher and the filling factor of the solar cell is larger. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a picture of the appearance of the perovskite film prepared in Example 1.

[0029] Figure 2 This is the SEM image of the perovskite film prepared in Example 1.

[0030] Figure 3 This is a picture of the appearance of the perovskite film prepared in Comparative Example 1.

[0031] Figure 4This is the UV-visible absorption spectrum of the perovskite film prepared in Example 1.

[0032] Figure 5 Transmission spectra of the perovskite films prepared in Examples 1 and 2 and Comparative Examples 2 and 3. DETAILED DESCRIPTION

[0033] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the invention of the present invention based on the disclosed content, and they should also fall within the scope of the present application.

[0034] The present invention is further described below by way of specific examples. The various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels unless otherwise specified. Unless otherwise specified, the contents described below are all weight contents. Unless otherwise specified, it is understood that the process is carried out at room temperature.

[0035] Spin coating equipment: Beijing Saide Case, KW-4B-I type spin coating machine;

[0036] Example 1

[0037] Preparation of perovskite film in ethanol atmosphere:

[0038] Take 30 mL of ethanol reagent and heat it at 40° C. for 5 minutes. Place the heated ethanol reagent in the spin coating equipment cavity so that the entire cavity is in an ethanol atmosphere environment.

[0039] CxP 2 Preparation of Br perovskite films and devices:

[0040] 272 mg of cesium iodide, 187 mg of lead bromide, and 235.5 mg of lead iodide powder were weighed and dissolved in 1 mL of dimethyl sulfoxide solvent, followed by stirring at room temperature for 12 hours to form a perovskite solution.

[0041] SnO with a concentration of 3wt% 2 The hydrogel solution was directly spin-coated on the clean conductive glass ITO at a spin-coating speed of 3000 rpm for 20 s, and then calcined at 150 °C for 30 min to obtain a non-modified SnO with a thickness of 40 nm. 2 Film substrate.

[0042] Then SnO 2 The film substrate was placed on the rotating platform of the spin coating equipment, and 40 μL of the perovskite solution was spin coated (spin coating speed 4000 rpm, spin coating time 40 s, acceleration 2000 rpm, room temperature environment) on the SnO2 On the film substrate, the film was heated at 160°C for 20 minutes to form the corresponding perovskite absorption layer film. After the film cooled, a poly-3-hexylthiophene (P3HT) hole layer was spin-coated (15 mg / mL chlorobenzene solution, spin coating speed 2000 rpm, spin coating time 20 s, acceleration 1000 rpm), and a silver electrode was evaporated. The thickness of the silver electrode was 80 nm, and the corresponding perovskite solar cell was assembled. The effective area of ​​the cell was 0.0625 cm 2 .

[0043] Example 2

[0044] Preparation of perovskite film in ethyl acetate atmosphere:

[0045] Take 30 mL of ethyl acetate reagent and heat it at 40° C. for 5 minutes. Place the heated ethyl acetate reagent in the spin coating equipment cavity so that the entire cavity is in an ethanol atmosphere environment.

[0046] CxP 2 The preparation process of the Br perovskite film and device is the same as that in Example 1.

[0047] Comparative Example 1

[0048] No heated low-boiling point solvent is placed in the spin coating chamber, CsPbI 2 The preparation process of the Br perovskite film and device is the same as that in Example 1.

[0049] Comparative Example 2

[0050] The ethanol reagent in Example 1 and the perovskite solution were mixed to prepare CsPbI 2 The rest of the preparation process of the Br perovskite film and device is the same as that of Example 1.

[0051] Comparative Example 3

[0052] The ethyl acetate reagent in Example 2 and the perovskite solution were mixed to prepare CsPbI 2 The rest of the preparation process of the Br perovskite film and device is the same as that of Example 2.

[0053] Results

[0054] 1. Fill factor

[0055] Through the solar simulator, at 100mWcm -2 Under the irradiation of standard light, the filling factors of Examples 1-2 and Comparative Examples 1-3 were tested. The test results are shown in Table 1.

[0056] Table 1. Test results of Examples 1-2 and Comparative Examples 1-3

[0057] <![CDATA[Current density / mAcm -2 > Open circuit voltage / V Fill factor / % Example 1 10.32 1.26 83.1 Example 2 10.13 1.20 81.7 Comparative Example 1 15.55 1.20 78.9 Comparative Example 2 15.11 1.27 82.1 Comparative Example 3 15.03 1.26 81.2

[0058] Compared with comparative examples 1-3, the filling factor of example 1-2 is larger. From the above results, it can be seen that preparing the perovskite film in a low boiling point solvent atmosphere can improve the filling factor of the formed perovskite solar cell and enhance the charging performance of the solar cell.

[0059] 2. Transmittance

[0060] 2.1 Detection Method

[0061] The transmittance of the corresponding films was tested using an ultraviolet-visible spectrophotometer, and a light source wavelength of 295 nm was selected. Air was used as a reference, and the pure ITO transmission rate was used as a secondary control. The film tests were carried out in sequence.

[0062] 2.2 Test results

[0063] Depend on Figure 5 It can be seen that compared with comparative example 2-3, the light transmittance of example 1-2 is better.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a transparent perovskite film with a high filling factor, characterized in that: The following steps are involved: S1. placing a heated low-boiling-point solvent in a spin coating device so that the spin coating device is filled with a vapor atmosphere of the low-boiling-point solvent; S2, preparing perovskite solution based on CsI, PbBr2, and PbI2; S3, placing the electron transport layer substrate on a rotating platform of a spin coating device, spin coating the perovskite solution on the electron transport layer substrate, and obtaining a transparent perovskite film with a high filling factor after heating treatment; In step S1, the low boiling point solvent is selected from at least one of methanol, ethanol, propanol, ethyl acetate, methyl ether, ethyl ether, and propyl ether; In step S3, the electron transport layer substrate is selected from any one of a SnO2 substrate and a TiO2 substrate.

2. The preparation method according to claim 1, characterized in that: In step S1, the low boiling point solvent is selected from at least one of ethanol and ethyl acetate.

3. The preparation method according to claim 2, characterized in that: In step S1, the low boiling point solvent is ethanol.

4. The preparation method according to claim 1, characterized in that: In step S2, the solvent of the perovskite solution is dimethyl sulfoxide.

5. The preparation method according to claim 4, characterized in that: In step S2, the concentration of CsI in the perovskite solution is 200-400 mg / mL; the molar ratio of CsI, PbBr2, and PbI2 is 1-4:1-2:1-2.

6. The preparation method according to claim 5, characterized in that: In step S2, the concentration of CsI in the perovskite solution is 272 mg / mL; the molar ratio of CsI, PbBr2, and PbI2 is 2.06:1:

1.

7. The preparation method according to claim 1, characterized in that: In step S3, the specific conditions of the heating treatment are: 140-180° C., 15-40 min.

8. A perovskite solar cell, characterized in that: The invention comprises a transparent perovskite film with a high filling factor prepared by the preparation method according to any one of claims 1 to 7.

9. The perovskite solar cell according to claim 8, characterized in that: It also includes a cavity layer and a silver electrode.

10. Application of a transparent perovskite film with a high filling factor prepared by the preparation method according to any one of claims 1 to 7 in a solar cell.

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