Preparation method and application of perovskite composite film

Abstract

The invention discloses a preparation method and application of a perovskite composite film, and the method comprises the steps: immersing a perovskite film in a solution containing ionic liquid to form an ionic liquid-perovskite composite layer, and obtaining the perovskite composite film; the solution containing the ionic liquid consists of organic cations and anions; the anions include halogen anions, tetrafluoroborate anions, hexafluorophosphate anions, or any anion group comprising the F element. According to the invention, the ionic liquid is used as a passivating agent, and a stable passivation layer is formed through chemical bonding between the passivating agent and Pb < 2 + > and I <-> ions on the surface of perovskite, so that surface and interface defects are effectively passivated, non-radiative recombination is reduced, the service life of current carriers is prolonged, and the photoelectric conversion efficiency and long-term stability of the solar cell are remarkably improved; the method is suitable for the perovskite solar cell with rigid and flexible substrates, not only improves the performance of the perovskite solar cell, but also has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and more specifically, to a preparation method and application of a perovskite composite film. Background Art

[0002] Perovskite solar cells have attracted extensive attention due to their high photoelectric conversion efficiency, low cost, and simple preparation process. However, their long-term stability remains a major obstacle to commercialization, especially due to the migration of halide ions and the degradation of Pb 2+ Incomplete coordination of ions. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing and applying a perovskite composite film, which effectively passivates surface and interface defects, reduces non-radiative recombination, and increases carrier lifetime, thereby significantly improving the photoelectric conversion efficiency and long-term stability of solar cells by forming an ionic liquid-perovskite composite layer on the surface of the perovskite film.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A method for preparing a perovskite composite film, the method comprising: immersing a perovskite film in a solution containing an ionic liquid to form an ionic liquid-perovskite composite layer, thereby obtaining the perovskite composite film; the solution containing the ionic liquid is composed of organic cations and anions; the anions include halogen anions, tetrafluoroborate anions, hexafluorophosphate anions or any anion group containing the F element; the organic cations include at least one of quaternary ammonium salt cations, quaternary phosphonium salt cations, imidazolium salt cations, pyrrolidine cations, morpholinium cations, piperidinium cations and sulfonium cations.

[0006] Specifically, the present invention uses ionic liquid as a passivating agent, which reacts with Pb 2+ and I - The chemical bonding of ions forms a stable passivation layer, thereby improving the efficiency and stability of the battery.

[0007] Optionally, the ionic liquid solution is a mixture of the ionic liquid and isopropanol or ethanol in a volume ratio of 1:1000 to 1:10000.

[0008] The present invention also discloses an application of a perovskite composite film prepared by the above-mentioned preparation method in a solar cell, wherein the solar cell structure is a regular structure or a trans structure: when the solar cell structure is a regular structure, its structure includes, from bottom to top, a substrate, a transparent conductive electrode, an electron transport layer, a perovskite composite film, a hole transport layer and a metal electrode; when the solar cell structure is a trans structure, its structure includes, from bottom to top, a substrate, a transparent conductive electrode, a hole transport layer, a perovskite composite film, an electron transport layer and a metal electrode.

[0009] Optionally, the substrate includes a rigid substrate or a flexible substrate.

[0010] Optionally, the rigid substrate comprises a glass or metal plate.

[0011] Optionally, the flexible substrate includes at least one of metal foil, polyethylene terephthalate, polyethylene naphthalate and polyimide.

[0012] Optionally, the transparent conductive electrode includes indium tin oxide or fluorine-doped tin oxide.

[0013] Optionally, the electron transport layer includes at least one of ZnO, TiO2, SnO2, CBM, and C60.

[0014] Optionally, the hole transport layer includes SAM material, NiO x , CuI, Cu2O, Spiro-MeOTAD, Spiro-TTB, NPB, PTAA.

[0015] Optionally, the thickness of the perovskite composite film is 15 nm to 50 nm, preferably 15 nm.

[0016] Implementing the embodiments of the present invention will have the following beneficial effects:

[0017] The present invention provides a method for improving the stability and efficiency of perovskite solar cells by using ionic liquid as a passivation layer. The ionic liquid is used as a passivation agent to react with Pb on the surface of the perovskite. 2+ and I - The chemical bonding of ions forms a stable passivation layer, which effectively passivates surface and interface defects, reduces non-radiative recombination, and increases carrier lifetime, thereby significantly improving the photoelectric conversion efficiency and long-term stability of solar cells. It is suitable for perovskite solar cells on rigid and flexible substrates, which not only improves the performance of perovskite solar cells, but also has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing the mechanism of action of the perovskite solar cell of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0020] Example 1: Preparation of perovskite solar cells on a rigid glass substrate

[0021] Substrate preparation: FTO (fluorine-doped tin oxide) glass with a size of 25 mm × 25 mm was selected as the substrate.

[0022] Transparent conductive electrode: The existing FTO layer on the substrate is confirmed to be a transparent conductive electrode.

[0023] Electron transport layer: A SnO2 electron transport layer was deposited on the FTO glass substrate by spin coating.

[0024] Perovskite composite film: spin-coat the perovskite precursor solution on the electron transport layer and form a perovskite layer after annealing; immerse the perovskite layer in a solution containing an ionic liquid, wherein the ionic liquid is composed of 1-ethyl-3-methylimidazole organic cations and bromide anions in a molar ratio of 1:1, the volume ratio of the ionic liquid to the isopropanol solvent is 1:1000, and the thickness is 5nm-50nm.

[0025] Hole transport layer: A Spiro-MeOTAD hole transport layer was deposited on the perovskite composite film.

[0026] Metal electrode: A metal electrode is evaporated on the hole transport layer to form a complete solar cell structure.

[0027] Stability test: The prepared perovskite solar cell was placed in an environmental chamber with an internal environment of 23°C, oxygen content <1%, relative humidity <1%, and air pressure 1.0atm. After 24 hours, it was packaged and tested for its stability. The efficiency of the final device was maintained at more than 99% of the initial efficiency value.

[0028] Example 2: Preparation of perovskite solar cells on flexible polyimide substrates

[0029] Substrate preparation: A polyimide film with a size of 20 mm × 20 mm was selected as the flexible substrate.

[0030] Transparent conductive electrode: A layer of indium tin oxide (ITO) was deposited on a polyimide substrate by magnetron sputtering technology as a transparent conductive electrode.

[0031] Electron transport layer: As in Example 1, an electron transport layer is deposited.

[0032] Perovskite composite film: Similar to Example 1, a perovskite precursor solution is spin-coated and annealed to form a perovskite layer, and the perovskite layer is immersed in an ionic liquid solution to form a perovskite composite film.

[0033] Hole transport layer: As in Example 1, a hole transport layer was deposited.

[0034] Metal electrode: Same as in Example 1, a metal electrode is evaporated.

[0035] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained above 99% of the initial efficiency value.

[0036] Embodiment 3:

[0037] The only difference between this embodiment and embodiment 1 is that the solution containing the ionic liquid is composed of 1-ethyl-3-methylimidazolium organic cation and tetrafluoroborate anion in a molar ratio of 1:1, and the volume ratio of the ionic liquid to the isopropanol solvent is 1:1000.

[0038] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained above 99% of the initial efficiency value.

[0039] Example 4

[0040] The only difference between this embodiment and embodiment 1 is that the solution containing the ionic liquid is composed of 1,3-dimethylimidazolium organic cations and hexafluorophosphate anions in a molar ratio of 1:1, and the volume ratio of the ionic liquid to the isopropanol solvent is 1:1000.

[0041] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained above 99% of the initial efficiency value.

[0042] Example 5

[0043] The only difference between this embodiment and embodiment 1 is that the solution containing the ionic liquid is composed of 1,3-dimethylimidazole organic cations and iodide anions in a molar ratio of 1:1, and the volume ratio of the ionic liquid to the isopropanol solvent is 1:1000.

[0044] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained above 99% of the initial efficiency value.

[0045] Example 6

[0046] The only difference between this embodiment and embodiment 1 is that the volume ratio of the ionic liquid to the solvent isopropanol is 1:2000.

[0047] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained above 99% of the initial efficiency value.

[0048] Example 7

[0049] The only difference between this embodiment and embodiment 1 is that the volume ratio of the ionic liquid to the solvent isopropanol is 1:5000.

[0050] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained above 99% of the initial efficiency value.

[0051] Example 8

[0052] The only difference between this embodiment and embodiment 1 is that the volume ratio of the ionic liquid to the solvent isopropanol is 1:10000.

[0053] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. Finally, the efficiency of the device was maintained at 99% of the initial efficiency value.

[0054] Comparative Example 1

[0055] The only difference between this comparative example and Example 1 is that the volume ratio of the ionic liquid to the solvent isopropanol is 1:20000.

[0056] Environmental adaptability test: The prepared perovskite solar cell was placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for its stability. The efficiency of the final device was maintained at 85% of the initial efficiency value.

[0057] Comparative Example 2

[0058] The only difference between this comparative example and Example 1 is that the perovskite layer in the solar cell of this comparative example is not treated with ionic liquid, and the perovskite precursor solution is only spin-coated on the surface of the electron transport layer and annealed to form the perovskite layer.

[0059] Environmental adaptability test: The prepared perovskite solar cells were placed in an environmental chamber, first kept in an environment with an oxygen content of less than 1%, a relative humidity of less than 1%, and an air pressure of 0.0005Pa for 12 hours, then switched to an environment with an oxygen content of 21%, a relative humidity of less than 1%, and an atmospheric pressure for 12 hours, then packaged and tested for stability. The efficiency of the final device was maintained at 76% of the initial efficiency value.

[0060] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a perovskite composite film, characterized in that: The method comprises: immersing the perovskite film in a solution containing an ionic liquid to form an ionic liquid-perovskite composite layer to obtain the perovskite composite film; The solution containing the ionic liquid is composed of organic cations and anions; The anion includes a halogen anion, a tetrafluoroborate anion, a hexafluorophosphate anion, or any anion group containing the F element; The organic cation includes at least one of a quaternary ammonium salt cation, a quaternary phosphonium salt cation, an imidazolium salt cation, a pyrrolidine cation, a morpholinium cation, a piperidinium cation, and a sulfonium cation.

2. The method for preparing a perovskite composite film according to claim 1, characterized in that: The solution containing the ionic liquid is a mixture of the ionic liquid and isopropanol or ethanol in a volume ratio of 1:1000 to 1:10000; The molar ratio of the organic cation to the anion is 1:

1.

3. An application of a perovskite composite film prepared by the preparation method according to any one of claims 1 to 2 in a solar cell, characterized in that: The solar cell structure is a regular structure or a trans structure: When the solar cell structure is a formal structure, the structure includes, from bottom to top, a substrate, a transparent conductive electrode, an electron transport layer, a perovskite composite film, a hole transport layer and a metal electrode; When the solar cell structure is a trans-structure, the structure includes, from bottom to top, a substrate, a transparent conductive electrode, a hole transport layer, a perovskite composite film, an electron transport layer and a metal electrode.

4. The use according to claim 3, characterized in that: The substrate includes a rigid substrate or a flexible substrate.

5. The use according to claim 4, characterized in that: The rigid substrate comprises a glass or metal plate; The flexible substrate includes at least one of metal foil, polyethylene terephthalate, polyethylene naphthalate, and polyimide.

6. The use according to claim 3, characterized in that: The transparent conductive electrode includes indium tin oxide or fluorine-doped tin oxide.

7. The use according to claim 3, characterized in that: The electron transport layer includes at least one of ZnO, TiO2, SnO2, CBM, and C60.

8. The use according to claim 3, characterized in that: The hole transport layer includes SAM material, NiO x , CuI, Cu2O, Spiro-MeOTAD, Spiro-TTB, NPB, PTAA.

9. The use according to claim 3, characterized in that: The thickness of the perovskite composite film is 5nm-50nm.

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