Post-processing method of perovskite thin film, perovskite solar cell and preparation method of perovskite solar cell

Abstract

The invention provides a post-processing 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 post-treatment method comprises the following steps: S1, dissolving dimethylaminobenzopyridine in a solvent to obtain an interface modification material solution; s2, coating a perovskite thin film with the interface modification material solution to obtain an interface modification layer wet film; and S3, carrying out heat treatment on the interface modification layer wet film to obtain the interface modification layer. According to the post-processing method, an interface modification layer is introduced between a perovskite thin film and a transmission layer, and the interface modification layer can optimize the energy level matching between the perovskite thin film and the transmission layer, reduce the interface potential barrier and improve the separation and transmission efficiency of current carriers, so that the photoelectric conversion efficiency of the perovskite solar cell can be improved; in addition, the interface modification layer also has a function of blocking water and oxygen, so that the stability of the perovskite solar cell can be improved.

Description

Technical Field

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

[0002] Due to their high photoelectric conversion performance and low-cost manufacturing process, perovskite solar cells have become a research hotspot in the photovoltaic field in recent years. However, the interface defect problem of perovskite thin films themselves significantly affects the stability and photoelectric conversion efficiency of their optoelectronic devices. There are usually problems of energy level mismatch, grain boundary defects, and interface instability at the interfaces between perovskite thin films and electron transport layers and hole transport layers. These defects will lead to increased carrier recombination and increased interface impedance, thereby reducing the conversion efficiency of perovskite solar cells. In addition, the uncoordinated ions and polar molecules at the above-mentioned interfaces are also easily eroded by water and oxygen in the environment, further accelerating the decay of device performance. Therefore, interface modification technology has become an important research direction for improving the performance of perovskite solar cells.

[0003] Existing research shows that by introducing an interface modification material between the perovskite thin film and the transport layer or chemically passivating the surface of the perovskite thin film, interface defects can be effectively reduced, interface stability can be improved, and carrier transport efficiency can be enhanced. By reasonably designing the interface modification strategy, not only can carrier recombination be inhibited, but also the moisture resistance and antioxidant ability of the device can be enhanced, and the device life can be extended. Therefore, developing new perovskite interface modification methods has important scientific research and practical application values. 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 post-treatment method for perovskite thin films, a perovskite solar cell, and a preparation method thereof. The post-treatment method introduces an interface modification layer between the perovskite thin film and the transport layer. The interface modification layer can optimize the energy level matching between the perovskite thin film and the transport layer, reduce the interface barrier, and improve the separation and transport efficiency of carriers, thereby improving the photoelectric conversion efficiency of the perovskite solar cell; in addition, the interface modification layer also has the function of blocking water and oxygen, thereby improving the stability of the perovskite solar cell.

[0005] An embodiment of the present invention provides a post-treatment method for perovskite thin films, including the following steps:

[0006] S1. Dissolve dimethylaminobenzopyridine in a solvent to obtain an interface modification material solution;

[0007] S2. Coat the interface modification material solution on the perovskite thin film to obtain a wet film of the interface modification layer;

[0008] S3. Heat-treat the wet film of the interface modification layer to obtain the interface modification layer.

[0009] The advantages and technical effects brought by the post-treatment method of the embodiments of the present invention are as follows:

[0010] (1) The post-treatment method of the embodiments of the present invention forms an interface modification layer on the surface of the prepared perovskite film by coating an interface modification material solution with dimethylaminobenzopyridine as the active ingredient.

[0011] (2) As an interface modification material, dimethylaminobenzopyridine can form a low-dimensional perovskite structure with the perovskite film through the dimethylamino group on the benzene ring, thereby optimizing the energy level matching between the perovskite film and the transport layer, reducing the interface barrier, improving the separation and transport efficiency of carriers, and thus improving the photoelectric conversion efficiency of the perovskite solar cell; moreover, the dimethylamino group on the benzene ring can also improve the water and oxygen erosion resistance of the perovskite film, thereby improving the stability of the perovskite solar cell. In addition, the nitrogen atom on the benzene ring can also form a coordination interaction with lead ions in the perovskite film to passivate interface defects and improve the optoelectronic properties of the perovskite film.

[0012] In some embodiments, in the interface modification material solution, the concentration of dimethylaminobenzopyridine is 0.01 - 2 mg / mL.

[0013] In some embodiments, the solvent is isopropyl alcohol and / or trifluoroethanol.

[0014] In some embodiments, the coating amount of the interface modification material solution is 80 - 150 μL of the interface modification material solution per square centimeter of the perovskite film.

[0015] In some embodiments, the coating method of the interface modification material solution is spin coating, dip coating, blade coating or slot die coating.

[0016] In some embodiments, the heat treatment holding temperature is 80 - 120 °C, and the heat treatment holding time is 5 - 30 min.

[0017] In addition, the embodiments of the present invention provide a perovskite solar cell, in which an interface modification layer is provided between the perovskite film and the electron transport layer, or an interface modification layer is provided between the perovskite film and the hole transport layer, and the material of the interface modification layer is dimethylaminobenzopyridine.

[0018] The advantages and technical effects brought by the perovskite solar cell of the embodiments of the present invention are as follows:

[0019] (1) In the perovskite solar cell of the embodiment of the present invention, an interfacial modification layer formed by dimethylaminobenzopyridine is introduced between the perovskite thin film and the transport layer.

[0020] (2) Dimethylaminobenzopyridine is used as an interfacial modification material. The dimethylamino group on the benzene ring can form a low-dimensional perovskite structure with the perovskite thin film, thereby optimizing the energy level matching between the perovskite thin film and the transport layer, reducing the interfacial barrier, and enhancing the separation and transport efficiency of carriers, so as to improve the photoelectric conversion efficiency of the perovskite solar cell; moreover, the dimethylamino group on the benzene ring can also enhance the resistance of the perovskite thin film to water and oxygen erosion, thereby improving the stability of the perovskite solar cell. In addition, the nitrogen atom on the benzene ring can also form a coordination effect with lead ions in the perovskite thin film to passivate interfacial defects and improve the optoelectronic properties of the perovskite thin film.

[0021] In addition, the embodiment of the present invention also provides a preparation method of a perovskite solar cell. The preparation method uses the following post-treatment method to prepare the interfacial modification layer, and the post-treatment method includes the following steps:

[0022] S1. Dissolve dimethylaminobenzopyridine in a solvent to obtain an interfacial modification material solution;

[0023] S2. Coat the interfacial modification material solution on the perovskite thin film to obtain a wet film of the interfacial modification layer;

[0024] S3. Heat-treat the wet film of the interfacial modification layer to obtain the interfacial modification layer.

[0025] 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:

[0026] Since the post-treatment method of the embodiment of the present invention is used to prepare the interfacial modification layer, an interfacial modification layer made of dimethylaminobenzopyridine 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.

[0027] In some embodiments, in the interfacial modification material solution, the concentration of dimethylaminobenzopyridine is 0.01 - 2 mg / mL.

[0028] In some embodiments, the coating amount of the interfacial modification material solution is 80 - 150 μL of the interfacial modification material solution per square centimeter of the perovskite thin film. Description of the Drawings

[0029] Figure 1 is the structural formula of dimethylaminobenzopyridine.

[0030] Figure 2 It is the current-voltage curve graphs of the perovskite solar cells before and after aging in Example 1 and Comparative Example 1. Detailed implementation manners

[0031] 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 accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0032] The embodiments of the present invention provide a post-treatment method for a perovskite thin film, including the following steps:

[0033] S1. Dissolve dimethylaminobenzopyridine (the structural formula is as Figure 1 shown) in a solvent to obtain an interfacial modification material solution;

[0034] S2. Coat the interfacial modification material solution on the perovskite thin film to obtain a wet film of the interfacial modification layer;

[0035] S3. Heat-treat the wet film of the interfacial modification layer to obtain an interfacial modification layer.

[0036] The post-treatment method of the embodiments of the present invention forms an interfacial modification layer on the surface of the prepared perovskite thin film by coating an interfacial modification material solution with dimethylaminobenzopyridine as the active ingredient. Dimethylaminobenzopyridine is used as the interfacial modification material. The dimethylamino group on the benzene ring can form a low-dimensional perovskite structure with the perovskite thin film, thereby optimizing the energy level matching between the perovskite thin film and the transport layer, reducing the interfacial barrier, and improving the separation and transport efficiency of carriers, thereby improving the photoelectric conversion efficiency of the perovskite solar cell; moreover, the dimethylamino group on the benzene ring can also improve the water and oxygen erosion resistance of the perovskite thin film, thereby improving the stability of the perovskite solar cell. In addition, the nitrogen atom on the benzene ring can also form a coordination effect with lead ions in the perovskite thin film to passivate interfacial defects and improve the optoelectronic properties of the perovskite thin film.

[0037] In some embodiments, in the interfacial modification material solution, the concentration of dimethylaminobenzopyridine 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 dimethylaminobenzopyridine in the interfacial modification material solution is too low, the thickness of the interfacial modification layer obtained with the same coating amount of the interfacial modification material 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 dimethylaminobenzopyridine in the interfacial modification material solution is too high, it is not conducive to the uniform coating of the interfacial modification material solution, and it is also not conducive to improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0038] In some embodiments, the solvent is isopropyl alcohol and / or trifluoroethanol. The above alcohol solvents have good solubility in dimethylaminobenzopyridine and are more easily evaporated and removed during the heat treatment of the wet film of the interface modification layer after the coating of the interface modification material solution.

[0039] In some embodiments, the coating amount of the interface modification material solution is 80 - 150 μL of the interface modification material solution per square centimeter of the perovskite film coating. When the coating amount of the interface modification material solution is too small, the thickness of the obtained interface modification layer 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 interface modification material 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.

[0040] In some embodiments, the coating method of the interface modification material solution is spin coating, dip coating, blade coating or slot coating, etc. The above-listed coating methods can uniformly coat the interface modification material solution on the surface of the perovskite film.

[0041] 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 interface modification layer to obtain the interface modification layer. 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.

[0042] In addition, the embodiments of the present invention provide a perovskite solar cell, in which an interface modification layer is provided between the perovskite film and the electron transport layer, or an interface modification layer is provided between the perovskite film and the hole transport layer, and the material of the interface modification layer is dimethylaminobenzopyridine.

[0043] The perovskite solar cell of the embodiments of the present invention introduces an interface modification layer formed by dimethylaminobenzopyridine between the perovskite film and the transport layer. Dimethylaminobenzopyridine is used as the interface modification material, and the dimethylamino group on the benzene ring can form a low-dimensional perovskite structure with the perovskite film, thereby optimizing the energy level matching between the perovskite film and the transport layer, reducing the interface barrier, and improving the separation and transport efficiency of carriers, so as to improve the photoelectric conversion efficiency of the perovskite solar cell; moreover, the dimethylamino group on the benzene ring can also improve the water and oxygen erosion resistance of the perovskite film, thereby improving the stability of the perovskite solar cell. In addition, the nitrogen atom on the benzene ring can also form a coordination effect with the lead ions in the perovskite film to passivate the interface defects and improve the optoelectronic properties of the perovskite film.

[0044] It should be noted that the structure of a conventional perovskite solar cell is a conductive substrate / electron transport layer / perovskite thin film / hole transport layer / optionally a buffer layer / electrode. Therefore, the structure of the perovskite solar cell prepared by the post-treatment method of the embodiments of the present invention is a conductive substrate / electron transport layer / perovskite thin film / interface modification layer / hole transport layer / optionally a buffer layer / electrode, and an interface modification layer is introduced between the perovskite thin film and the hole transport layer. The structure of a reverse perovskite solar cell is a conductive substrate / hole transport layer / perovskite thin film / electron transport layer / optionally a buffer layer / electrode. Therefore, the structure of the perovskite solar cell prepared by the post-treatment method of the embodiments of the present invention is a conductive substrate / hole transport layer / perovskite thin film / interface modification layer / electron transport layer / optionally a buffer layer / electrode, and an interface modification layer is introduced between the perovskite thin film and the electron transport layer.

[0045] In addition, the embodiments of the present invention also provide a preparation method of a perovskite solar cell. The preparation method uses the following post-treatment method to prepare the interface modification layer, and the post-treatment method includes the following steps:

[0046] S1. Dissolve dimethylaminobenzopyridine in a solvent to obtain an interface modification material solution;

[0047] S2. Coat the interface modification material solution on the perovskite thin film to obtain a wet film of the interface modification layer;

[0048] S3. Heat-treat the wet film of the interface modification layer to obtain the interface modification layer.

[0049] Since the post-treatment method of the embodiments of the present invention is used to prepare the interface modification layer, an interface modification layer made of dimethylaminobenzopyridine 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 embodiments of the present invention can effectively improve the photoelectric conversion efficiency and stability of the battery.

[0050] In some embodiments, in the interface modification material solution, the concentration of dimethylaminobenzopyridine is 0.01 - 2 mg / mL.

[0051] In some embodiments, the coating amount of the interface modification material solution is 80 - 150 μL of the interface modification material solution per square centimeter of the perovskite thin film.

[0052] The present invention will be described in detail below with reference to the embodiments and the drawings.

[0053] Example 1

[0054] (1) Place (1×1 cm 2)Clean the ITO conductive glass, and magnetron sputter a 10-nm-thick nickel oxide film on the ITO conductive glass as the hole transport layer.

[0055] (2) Dissolve lead iodide, lead bromide, formamidinium iodide, and cesium iodide with a molar ratio of 0.85:0.15:0.78:0.22 in a mixed solution of DMF and DMSO with a volume ratio of 4:1 and mix evenly to obtain a perovskite precursor solution. Use a one-step method to spin-coat the perovskite precursor solution on the surface of the nickel oxide film at a speed of 3000 rpm for 30 s. Drop ethyl acetate as an antisolvent at the 20th second of 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 film.

[0056] (3) Dissolve dimethylaminobenzopyridine in isopropanol to obtain an interface modification material solution with a concentration of 0.5 mg / mL. Then, spin-coat the interface modification material solution on the surface of the perovskite film at a dosage of 80 μL of the interface modification material solution per square centimeter of the perovskite film at a speed of 4000 rpm for 30 s to obtain an interface modification layer wet film, and then heat-treat it at 100 °C for 10 min to obtain an interface modification layer.

[0057] (4) Place the sample prepared above in a vacuum thermal evaporation chamber. When the air pressure in the evaporation chamber is lower than 1×10 -5 Pa, start evaporating C 60 at an evaporation rate of 0.2 nm / s and deposit it on the perovskite 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 the C 60 layer to obtain a 3-nm-thick BCP layer; finally, evaporate Cu at an evaporation rate of 0.5 nm / s and deposit it on the BCP layer to obtain a 100-nm-thick Cu electrode layer. Thus, a perovskite solar cell is obtained.

[0058] Example 2

[0059] This example has the same method as Example 1, except that in step (3), the concentration of dimethylaminobenzopyridine in the interface modification material solution is 1 mg / mL.

[0060] Example 3

[0061] This example has the same method as Example 1, except that in step (3), the concentration of dimethylaminobenzopyridine in the interface modification material solution is 2 mg / mL.

[0062] Example 4

[0063] This embodiment is the same as the method of Embodiment 1, except that in step (3), the solvent used to prepare the interfacial modification material solution is trifluoroethanol.

[0064] Comparative Example 1

[0065] This comparative example is the same as the method of Embodiment 1, except that step (3) is omitted, and the resulting perovskite solar cell lacks an interfacial modification layer.

[0066] Performance Test

[0067] The perovskite solar cells obtained in each of the examples and comparative examples 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 curves of the perovskite solar cells of Embodiment 1 and Comparative Example 1 before and after aging are as Figure 2 shown.

[0068] Table 1. Photoelectric conversion efficiencies of the perovskite solar cells of each example and comparative example

[0069]

[0070] 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 can be combined in a suitable manner in any one or more embodiments or examples. 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.

[0071] 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 post-treatment method for a perovskite film, characterized in that: The following steps are involved: S1. dissolving dimethylaminobenzopyridine in a solvent to obtain an interface modification material solution; S2. coating the interface modification material solution on the perovskite film to obtain an interface modification layer wet film; S3. heat-treating the wet film of the interface modification layer to obtain an interface modification layer.

2. The post-processing method according to claim 1, characterized in that: In the interface modification material solution, the concentration of dimethylaminobenzopyridine is 0.01-2 mg / mL.

3. The post-processing method according to claim 1 or 2, characterized in that: The solvent is isopropanol and / or trifluoroethanol.

4. The post-processing method according to claim 1 or 2, characterized in that: The coating amount of the interface modification material solution is 80-150 μL of the interface modification material solution per square centimeter of the perovskite film.

5. The post-processing method according to claim 1 or 2, characterized in that: The interface modification material solution is coated by spin coating, dip coating, scraping coating or slit coating.

6. The post-processing 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.

7. A perovskite solar cell, characterized in that: An interface modification layer is arranged between the perovskite film and the electron transport layer, or an interface modification layer is arranged between the perovskite film and the hole transport layer, and the material of the interface modification layer is dimethylaminobenzopyridine.

8. The method for preparing a perovskite solar cell according to claim 7, characterized in that: The interface modification layer is prepared by the following post-treatment method, which comprises the following steps: S1. dissolving dimethylaminobenzopyridine in a solvent to obtain an interface modification material solution; S2. coating the interface modification material solution on the perovskite film to obtain an interface modification layer wet film; S3. heat-treating the wet film of the interface modification layer to obtain the interface modification layer.

9. The preparation method according to claim 8, characterized in that: In the interface modification material solution, the concentration of dimethylaminobenzopyridine is 0.01-2 mg / mL.

10. The preparation method according to claim 8, characterized in that: The coating amount of the interface modification material solution is 80-150 μL of the interface modification material solution per square centimeter of the perovskite film.

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