Defect passivation method of perovskite thin film, perovskite solar cell and preparation method of perovskite solar cell

Abstract

The invention provides a defect passivation method of a perovskite thin film, a perovskite solar cell and a preparation method of the perovskite solar cell, and belongs to the technical field of perovskite solar cells. The defect passivation method comprises the following steps: S1, dissolving morpholine-4-formamidine hydrochloride in a solvent to obtain a passivation solution; s2, coating a perovskite thin film with the passivation solution to obtain a passivation wet film; and S3, the passive film wet film is subjected to heat treatment, and the passive film is obtained. According to the defect passivation method, the passivation film is introduced between the perovskite thin film and the electron transport layer or the hole transport layer, the defect state density of the interface of the perovskite thin film is reduced, the photoelectric conversion efficiency and the stability of the perovskite solar cell are improved, and the performance and the service life of the perovskite solar cell can be remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and particularly relates to a method for defect passivation of a perovskite thin film, a perovskite solar cell, and a preparation method thereof. Background Art

[0002] Perovskite solar cells have become the research focus of new photovoltaic technologies due to their high photoelectric performance and low-cost preparation process. However, due to the easy formation of surface and grain boundary defects in the perovskite crystal structure, these defects cause non-radiative recombination phenomena, seriously affecting the photoelectric conversion efficiency and long-term stability of the device. Therefore, finding efficient passivation materials to repair these defects and improve the performance of perovskite materials is an urgent problem to be solved.

[0003] To solve these problems, researchers have proposed an interface passivation technology. By introducing a passivation material, such as an organic molecule, a halide salt, or an oxide, between the perovskite thin film and the electron / hole transport layer, it is possible to effectively repair interface defects, reduce non-radiative recombination, and improve the efficiency and stability of the device. However, the passivation materials in the prior art have limited effects on improving the efficiency and stability of perovskite solar cells and need further research. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, an embodiment of the present invention provides a method for defect passivation of a perovskite thin film, a perovskite solar cell, and a preparation method thereof. The defect passivation method reduces the density of interface defect states of the perovskite thin film through the application of a novel passivation material, improves the photoelectric conversion efficiency and stability of the perovskite solar cell, and can significantly improve the performance and lifespan of the perovskite solar cell.

[0005] An embodiment of the present invention provides a method for defect passivation of a perovskite thin film, including the following steps:

[0006] S1. Dissolve morpholine-4-carboxamidine hydrochloride in a solvent to obtain a passivation solution;

[0007] S2. Coat the passivation solution on the perovskite thin film to obtain a wet passivation film;

[0008] S3. Heat-treat the wet passivation film to obtain a passivation film.

[0009] The advantages and technical effects brought by the defect passivation method of the embodiment of the present invention are:

[0010] (1) The defect passivation method of the embodiment of the present invention forms a passivation film on the surface of the prepared perovskite film by coating a passivation solution with morpholine-4-formamidine hydrochloride as the passivation material. Due to its unique chemical structure, morpholine-4-formamidine hydrochloride has a strong passivation effect on the surface of the perovskite film, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0011] (2) The formamidine group in morpholine-4-formamidine hydrochloride is a common component in the perovskite film, which can well fill the cation vacancies on the surface of the perovskite film, reduce vacancy defects, and improve the photoelectric conversion efficiency of the perovskite solar cell.

[0012] (3) The oxygen atom on the morpholine group in morpholine-4-formamidine hydrochloride has a lone pair of electrons, which can interact with the uncoordinated lead ions on the film surface, reduce the density of defect states on the surface of the perovskite film, and improve the photoelectric conversion efficiency of the perovskite solar cell; in addition, the morpholine ring can also stabilize the surface of the perovskite film, inhibit the intrusion of moisture and oxygen, prevent the degradation of the perovskite material, and improve the stability of the perovskite solar cell.

[0013] In some embodiments, the morpholine-4-formamidine hydrochloride is at least one of morpholine-4-formamidine chlorate, morpholine-4-formamidine bromate, and morpholine-4-formamidine iodate.

[0014] In some embodiments, in the passivation solution, the concentration of the morpholine-4-formamidine hydrochloride is 0.01 - 2 mg / mL.

[0015] In some embodiments, the solvent is isopropyl alcohol and / or trifluoroethanol.

[0016] In some embodiments, the coating amount of the passivation solution is 80 - 150 μL of the passivation solution per square centimeter of the perovskite film.

[0017] In some embodiments, the coating method of the passivation solution is spin coating, dip coating, blade coating, or slot die coating.

[0018] In some embodiments, the holding temperature of the heat treatment is 80 - 120 °C, and the holding time of the heat treatment is 5 - 30 min.

[0019] In addition, the embodiment of the present invention provides a perovskite solar cell, in which a passivation film is provided between the perovskite film and the electron transport layer, or a passivation film is provided between the perovskite film and the hole transport layer, and the material of the passivation film is morpholine-4-formamidine hydrochloride.

[0020] The advantages and technical effects brought by the defect passivation method of the embodiment of the present invention are:

[0021] (1) In the perovskite solar cell of the embodiment of the present invention, a passivation film with morpholine-4-carboxamidine hydrochloride as the active component is introduced between the perovskite thin film and the electron transport layer or the hole transport layer, which has a strong passivation effect on the surface of the perovskite thin film, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0022] (2) The formamidine group in morpholine-4-carboxamidine hydrochloride is a common component in the perovskite thin film, which can well fill the cation vacancies on the surface of the perovskite thin film, reduce the vacancy defects, and improve the photoelectric conversion efficiency of the perovskite solar cell.

[0023] (3) The oxygen atom on the morpholine group in morpholine-4-carboxamidine hydrochloride has lone pair electrons, which can interact with the uncoordinated lead ions on the film surface, reduce the density of defect states on the surface of the perovskite thin film, and improve the photoelectric conversion efficiency of the perovskite solar cell; in addition, the morpholine ring can also stabilize the surface of the perovskite thin film, inhibit the intrusion of moisture and oxygen, prevent the degradation of the perovskite material, and improve the stability of the perovskite solar cell.

[0024] In addition, the embodiment of the present invention also provides a preparation method of a perovskite solar cell. The preparation method uses the following defect passivation method to prepare the passivation film, and the defect passivation method includes the following steps:

[0025] S1. Dissolve morpholine-4-carboxamidine hydrochloride in a solvent to obtain a passivation solution;

[0026] S2. Coat the passivation solution on the perovskite thin film to obtain a wet passivation film;

[0027] S3. Heat-treat the wet passivation film to obtain the passivation film.

[0028] The advantages and technical effects brought by the preparation method of the perovskite solar cell of the embodiment of the present invention are as follows:

[0029] Since the defect passivation method of the embodiment of the present invention is used to prepare the passivation film, a passivation film made of morpholine-4-carboxamidine hydrochloride is introduced between the perovskite thin film and the electron transport layer or the hole transport layer. Therefore, the preparation method of the perovskite solar cell of the embodiment of the present invention can effectively improve the photoelectric conversion efficiency and stability of the battery.

[0030] In some embodiments, in the passivation solution, the concentration of morpholine-4-carboxamidine hydrochloride is 0.01-2 mg / mL; and / or, the coating amount of the passivation solution is 80-150 μL of the passivation solution per square centimeter of the perovskite thin film. Description of the Drawings

[0031] Figure 1It is the structural formula of morpholine-4-carboxamidine hydrochloride.

[0032] Figure 2 It is the current-voltage curve graphs of the perovskite solar cells in Example 1 and Comparative Example 1 before and after aging. Detailed implementation manners

[0033] The embodiments of the present invention will be described in detail below. The examples are shown in the accompanying drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0034] The embodiments of the present invention provide a method for defect passivation of a perovskite thin film, including the following steps:

[0035] S1. Dissolve morpholine-4-carboxamidine hydrochloride (such as Figure 1 the morpholine-4-carboxamidine hydrochloride shown) in a solvent to obtain a passivation solution;

[0036] S2. Coat the passivation solution on the perovskite thin film to obtain a wet passivation film;

[0037] S3. Heat-treat the wet passivation film to obtain a passivation film.

[0038] The defect passivation method of the embodiments of the present invention forms a passivation film on the surface of the prepared perovskite thin film by coating a passivation solution with morpholine-4-carboxamidine hydrochloride as the passivation material. Due to its unique chemical structure, morpholine-4-carboxamidine hydrochloride has a strong passivation effect on the surface of the perovskite thin film, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell. The defect passivation method of the embodiments of the present invention performs heat treatment after obtaining the wet passivation film. On the one hand, it is to evaporate and remove the solvent therein to obtain a passivation film, and on the other hand, it is to further improve the passivation effect.

[0039] The formamidine group in morpholine-4-carboxamidine hydrochloride is a common component in the perovskite thin film, which can well fill the cation vacancies on the surface of the perovskite thin film, reduce the vacancy defects, and improve the photoelectric conversion efficiency of the perovskite solar cell.

[0040] The oxygen atom on the morpholine group in morpholine-4-carboxamidine hydrochloride has lone pair electrons, which can interact with the uncoordinated lead ions on the film surface, reduce the density of defect states on the surface of the perovskite thin film, and improve the photoelectric conversion efficiency of the perovskite solar cell; in addition, the morpholine ring can also stabilize the surface of the perovskite thin film, inhibit the intrusion of moisture and oxygen, prevent the degradation of the perovskite material, and improve the stability of the perovskite solar cell.

[0041] In some embodiments, the morpholine-4-carboximidamide hydrochloride is at least one of morpholine-4-carboximidamide chlorate, morpholine-4-carboximidamide bromate, and morpholine-4-carboximidamide iodate.

[0042] In some embodiments, in the passivation solution, the concentration of the morpholine-4-carboximidamide hydrochloride is 0.01-2 mg / mL, such as 0.01 mg / mL, 0.05 mg / mL, 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, etc. When the concentration of the morpholine-4-carboximidamide hydrochloride in the passivation solution is too low, the thickness of the passivation film obtained under the same coating amount of the passivation solution is too small, which is not conducive to improving the photoelectric conversion efficiency and stability of the perovskite solar cell. When the concentration of the morpholine-4-carboximidamide hydrochloride in the passivation solution is too high, it is not conducive to the uniform coating of the passivation solution, and it is also not conducive to improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0043] In some embodiments, the solvent is isopropyl alcohol and / or trifluoroethanol. The above alcohol solvents have good solubility for morpholine-4-carboximidamide hydrochloride, and are more easily evaporated and removed when heat-treating the wet film of the passivation film after coating the passivation solution.

[0044] In some embodiments, the coating amount of the passivation solution is 80-150 μL of the passivation solution per square centimeter of the perovskite film. When the coating amount of the passivation solution is too small, the thickness of the obtained passivation film is too small, which is not conducive to improving the photoelectric conversion efficiency and stability of the perovskite solar cell. When the coating amount of the passivation solution is too large, cracks are likely to appear in the perovskite film, which will reduce the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0045] In some embodiments, the coating method of the passivation solution is spin coating, dip coating, blade coating, slot coating, etc. The above-listed coating methods can uniformly coat the passivation solution on the surface of the perovskite.

[0046] In some embodiments, the holding temperature of the heat treatment is 80-120 °C, such as 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, etc., and the holding time of the heat treatment is 5-30 min, such as 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc. When the holding temperature of the heat treatment is too low or the holding time is too short, it is not conducive to quickly removing the solvent in the wet film of the passivation film to obtain the passivation film. When the holding temperature of the heat treatment is too high or the holding time is too long, it is not conducive to cost reduction and efficiency improvement.

[0047] In addition, the embodiments of the present invention provide a perovskite solar cell, in which a passivation film is provided between the perovskite film and the electron transport layer, or a passivation film is provided between the perovskite film and the hole transport layer, and the material of the passivation film is morpholine-4-carboximidamide hydrochloride.

[0048] In the perovskite solar cell of the embodiment of the present invention, a passivation film with morpholine-4-carboxamidine hydrochloride as the active component is introduced between the perovskite film and the electron transport layer or the hole transport layer, which has a strong passivation effect on the surface of the perovskite film, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0049] The formamidine group in morpholine-4-carboxamidine hydrochloride is a common component in the perovskite film, which can well fill the cation vacancies on the surface of the perovskite film, reduce the vacancy defects, and improve the photoelectric conversion efficiency of the perovskite solar cell.

[0050] The oxygen atom on the morpholine group in morpholine-4-carboxamidine hydrochloride has lone pair electrons, which can interact with the uncoordinated lead ions on the film surface, reduce the density of defect states on the surface of the perovskite film, and improve the photoelectric conversion efficiency of the perovskite solar cell; in addition, the morpholine ring can also stabilize the surface of the perovskite film, inhibit the intrusion of moisture and oxygen, prevent the degradation of the perovskite material, and improve the stability of the perovskite solar cell.

[0051] It should be noted that the structure of a conventional perovskite solar cell is a conductive substrate / electron transport layer / perovskite film / hole transport layer / optionally a buffer layer / electrode. Therefore, the structure of the perovskite solar cell prepared by the defect passivation method of the embodiment of the present invention is a conductive substrate / electron transport layer / perovskite film / passivation layer / hole transport layer / optionally a buffer layer / electrode, and a passivation film is introduced between the perovskite film and the hole transport layer. The structure of a reverse perovskite solar cell is a conductive substrate / hole transport layer / perovskite film / electron transport layer / optionally a buffer layer / electrode. Therefore, the structure of the perovskite solar cell prepared by the defect passivation method of the embodiment of the present invention is a conductive substrate / hole transport layer / perovskite film / passivation layer / electron transport layer / optionally a buffer layer / electrode, and a passivation film is introduced between the perovskite film and the electron transport layer.

[0052] In addition, the embodiment of the present invention also provides a preparation method of a perovskite solar cell. The preparation method uses the following defect passivation method to prepare the passivation film, and the defect passivation method includes the following steps:

[0053] S1. Dissolve morpholine-4-carboxamidine hydrochloride in a solvent to obtain a passivation solution;

[0054] S2. Coat the passivation solution on the perovskite film to obtain a wet passivation film;

[0055] S3. Heat-treat the wet passivation film to obtain the passivation film.

[0056] Since the defect passivation method of the embodiment of the present invention is adopted to prepare the passivation film, a passivation film made of morpholine-4-carboxamidine hydrochloride is introduced between the perovskite thin film and the electron transport layer or the hole transport layer. Therefore, the preparation method of the perovskite solar cell of the embodiment of the present invention can effectively improve the photoelectric conversion efficiency and stability of the battery.

[0057] In some embodiments, in the passivation solution, the concentration of morpholine-4-carboxamidine hydrochloride is 0.01-2 mg / mL; and / or, the coating amount of the passivation solution is 80-150 μL of the passivation solution per square centimeter of the perovskite thin film.

[0058] The present invention will be described in detail below with reference to embodiments and drawings.

[0059] Example 1

[0060] (1) Clean a (1×1 cm 2 ) ITO conductive glass, and magnetron sputter a 10-nm-thick nickel oxide thin film on the ITO conductive glass as the hole transport layer.

[0061] (2) Dissolve lead iodide, lead bromide, formamidine iodide and cesium iodide with a molar ratio of 0.85:0.15:0.78:0.22 in a mixed solution with a volume ratio of DMF to DMSO of 4:1 and mix evenly to obtain a perovskite precursor solution. Spin-coat the perovskite precursor solution on the surface of the nickel oxide thin film by the one-step method at a rotation speed of 3000 rpm for 30 s, and add the antisolvent ethyl acetate at the 20th second of the spin-coating to obtain a perovskite wet film, and then anneal it at 100 °C for 20 min to obtain a 600-nm-thick perovskite thin film.

[0062] (3) Dissolve morpholine-4-carboxamidine chlorate in isopropanol to obtain a 0.5 mg / mL passivation solution, and then spin-coat the passivation solution on the surface of the perovskite thin film according to the dosage of 80 μL of the passivation solution per square centimeter of the perovskite thin film at a rotation speed of 4000 rpm for 30 s to obtain a passivation film wet film, and then heat-treat it at 100 °C for 10 min to obtain a passivation film.

[0063] (4) Place the sample prepared above in a vacuum thermal evaporation chamber, and start evaporating C -5 at an evaporation rate of 0.2 nm / s when the pressure in the evaporation chamber is lower than 1×10 60 and deposit it on the perovskite thin film to obtain a 30-nm-thick C 60 layer; then evaporate BCP at an evaporation rate of 0.1 nm / s and deposit it on C 60A BCP layer with a thickness of 3 nm is formed on the layer; finally, Cu is evaporated at an evaporation rate of 0.5 nm / s and deposited on the BCP layer to obtain a Cu electrode layer with a thickness of 100 nm, and thus a perovskite solar cell is obtained.

[0064] Example 2

[0065] The method of this example is the same as that of Example 1, except that in step (3), the concentration of morpholine-4-carboxamidine chlorate in the passivation solution is 1 mg / mL.

[0066] Example 3

[0067] The method of this example is the same as that of Example 1, except that in step (3), the concentration of morpholine-4-carboxamidine chlorate in the passivation solution is 2 mg / mL.

[0068] Example 4

[0069] The method of this example is the same as that of Example 1, except that in step (3), the solvent used to prepare the passivation solution is trifluoroethanol.

[0070] Example 5

[0071] The method of this example is the same as that of Example 1, except that in step (3), morpholine-4-carboxamidine bromate is used instead of morpholine-4-carboxamidine chlorate.

[0072] Example 6

[0073] The method of this example is the same as that of Example 1, except that in step (3), morpholine-4-carboxamidine iodate is used instead of morpholine-4-carboxamidine chlorate.

[0074] Comparative Example 1

[0075] The method of this comparative example is the same as that of Example 1, except that step (3) is omitted, and the resulting perovskite solar cell lacks a passivation film.

[0076] Performance Test

[0077] The perovskite solar cells obtained in each example and comparative example were subjected to photoelectric conversion efficiency tests. The test results are shown in Table 1. Then, they were stored in a glove box for 60 days of aging, and the photoelectric conversion efficiency tests are shown in Table 1. The current-voltage curve graphs of the perovskite solar cells of Example 1 and Comparative Example 1 before and after aging are as Figure 2 shown.

[0078] Table 1. Photoelectric conversion efficiency of perovskite solar cells in each example and comparative example

[0079]

[0080] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0081] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A defect passivation method for a perovskite film, characterized in that: The following steps are involved: S1. dissolving morpholine-4-carboxamidine hydrochloride in a solvent to obtain a passivation solution; S2. coating the passivation solution on the perovskite film to obtain a wet passivation film; S3. heat-treating the wet passivation film to obtain a passivation film.

2. The defect passivation method according to claim 1, characterized in that: The morpholine-4-carboxamidine hydrochloride is at least one of morpholine-4-carboxamidine chlorate, morpholine-4-carboxamidine bromide and morpholine-4-carboxamidine iodide.

3. The defect passivation method according to claim 1 or 2, characterized in that: In the passivation solution, the concentration of morpholine-4-carboxamidine hydrochloride is 0.01-2 mg / mL.

4. The defect passivation method according to claim 1 or 2, characterized in that: The solvent is isopropanol and / or trifluoroethanol.

5. The defect passivation method according to claim 1 or 2, characterized in that: The coating amount of the passivation solution is 80-150 μL per square centimeter of the perovskite film.

6. The defect passivation method according to claim 1 or 2, characterized in that: The passivation solution is coated by spin coating, dip coating, blade coating or slit coating.

7. The defect passivation method according to claim 1 or 2, characterized in that: The heat treatment is carried out at a holding temperature of 80-120° C. and for a holding time of 5-30 min.

8. A perovskite solar cell, characterized in that: A passivation film is arranged between the perovskite film and the electron transport layer, or a passivation film is arranged between the perovskite film and the hole transport layer, and the material of the passivation film is morpholine-4-carboxamidine hydrochloride.

9. The method for preparing a perovskite solar cell according to claim 8, characterized in that: The passivation film is prepared by the following defect passivation method, which comprises the following steps: S1. dissolving morpholine-4-carboxamidine hydrochloride in a solvent to obtain a passivation solution; S2. coating the passivation solution on the perovskite film to obtain a wet passivation film; S3. heat-treating the wet passivation film to obtain the passivation film.

10. The preparation method according to claim 9, characterized in that: In the passivation solution, the concentration of morpholine-4-carboxamidine hydrochloride is 0.01-2 mg / mL; and / or the coating amount of the passivation solution is 80-150 μL of the passivation solution per square centimeter of the perovskite film.

Images