Perovskite thin film and preparation method and application thereof

Abstract

The invention provides a perovskite thin film and a preparation method and application thereof. The preparation method of the perovskite thin film comprises the following steps: preparing a mixed solution containing a perovskite precursor solution and a tetraphenylethylene monomer; coating a substrate with the mixed solution to form a liquid film, and sequentially carrying out anti-solvent treatment and annealing treatment on the liquid film to obtain a perovskite thin film; the tetraphenylethylene monomer is selected from one or more of tetrakis (4-aminophenyl) ethylene, tetrakis (4-formyl phenyl) ethylene, tetrakis (4-aminophenyl) ethylene, tetrakis (4-aminophenyl) ethylene, tetrakis (4-formyl phenyl) ethylene, tetrakis (4-formyl phenyl) ethylene and tetrakis (4-boric acid phenyl) ethylene; the invention relates to a perovskite thin film ABX3 type organic-inorganic hybrid perovskite thin film. A perovskite precursor solution contains organic cations, lead ions and halide ions which form the ABX3 type organic-inorganic hybrid perovskite thin film. Based on the preparation method of the perovskite thin film, the problem of poor stability of the perovskite thin film in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to a solar cell, and in particular to a perovskite film and a preparation method and application thereof. Background Art

[0002] Metal halide perovskites have attracted widespread attention due to their low cost, simple preparation, long carrier diffusion distance, and adjustable band gap, and are considered to be the most promising light-absorbing materials in the next generation of photovoltaic technology. For example, the photoelectric conversion efficiency of perovskite solar cells has exceeded 26% so far. However, as an ionic crystal, perovskite has ionic bonding characteristics and is prone to ion migration. Its components are prone to react with water molecules and air in the environment, which ultimately causes the collapse of the perovskite crystal structure, causing the efficiency of perovskite solar cells to decay rapidly, greatly damaging the long-term stability of the device. Therefore, it is of great significance to develop perovskite films with good stability. Summary of the invention

[0003] The main purpose of the present invention is to provide a perovskite film and a preparation method and application thereof, so as to solve the problem of poor stability of the perovskite film in the prior art.

[0004] In order to achieve the above object, according to one aspect of the present invention, a method for preparing a perovskite film is provided, comprising the following steps:

[0005] Step S1, preparing a mixed solution including a perovskite precursor solution and a tetraphenylethylene monomer;

[0006] Step S2, coating the mixed solution on a substrate to form a liquid film, and sequentially performing anti-solvent treatment and annealing treatment on the liquid film to obtain a perovskite film;

[0007] Wherein, the tetraphenylethylene monomer is selected from one or more of tetrakis(4-aminophenyl)ethylene, tetrakis(4-formylphenyl)ethylene, tetrakis(4-aminobiphenyl)ethylene, tetrakis(4-formylbiphenyl)ethylene and tetrakis(4-boronic acid phenyl)ethylene;

[0008] The perovskite film is an ABX3 type organic-inorganic hybrid perovskite film, and the perovskite precursor solution contains organic cations, lead ions and halide ions that form the ABX3 type organic-inorganic hybrid perovskite film, and the organic cations are selected from methylamine ions and / or formamidine ions.

[0009] Furthermore, the content of the tetraphenylethylene monomer in the mixed solution is 0.01 mg / mL to 1 mg / mL.

[0010] Furthermore, the content of the tetraphenylethylene monomer in the mixed solution is 0.05 mg / mL to 0.5 mg / mL.

[0011] Furthermore, the concentration of the perovskite precursor solution is 0.5 mol / L to 2 mol / L based on ABX3.

[0012] Furthermore, the solvent in the perovskite precursor solution is selected from one of N,N-dimethylformamide and dimethyl sulfoxide, or a mixture of the two in any proportion.

[0013] Preferably, the solvent in the perovskite precursor solution is a mixed solvent formed by mixing N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (1-4):(1-2).

[0014] Furthermore, in step S2, the mixed liquid is coated on the substrate by spin coating to form a liquid film.

[0015] Preferably, the spin coating speed is 2000 rpm to 6000 rpm, and the spin coating time is 5 s to 50 s.

[0016] Furthermore, in the anti-solvent treatment, the anti-solvent is selected from one or more of toluene, chlorobenzene, cyclohexane, and ethyl acetate.

[0017] Furthermore, in the annealing treatment, the annealing temperature is 100° C. to 300° C., and the annealing time is 5 min to 60 min.

[0018] According to another aspect of the present invention, a perovskite film is provided, which is prepared according to the above method for preparing a perovskite film.

[0019] According to another aspect of the present invention, a solar cell is provided, comprising a light absorbing layer, wherein the light absorbing layer comprises the above perovskite film.

[0020] By applying the technical solution of the present invention, tetraphenylethylene monomers such as tetra(4-aminophenyl)ethylene are added as additives in the perovskite precursor solution. Tetraphenylethylene monomers such as tetra(4-aminophenyl)ethylene can interact with organic cations (such as methylamine or formamidine) in the perovskite material through hydrogen bonds and π-π stacking interactions between tetraphenylethylene monomers, thereby enhancing the intermolecular force, effectively fixing the organic cations in the perovskite structure, and inhibiting the collapse of the perovskite crystal structure, thereby improving the photoelectric conversion efficiency and long-term stability of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 A process flow chart of the method for preparing the perovskite thin film according to the present invention is shown. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] As described in the background art, the prior art has the problem of poor stability of perovskite films. In order to solve the above problem, Figure 1 According to one aspect of the present invention, a method for preparing a perovskite film is provided, comprising the following steps:

[0025] Step S1, preparing a mixed solution including a perovskite precursor solution and a tetraphenylethylene monomer;

[0026] Step S2, coating the mixed solution on a substrate to form a liquid film, and sequentially performing anti-solvent treatment and annealing treatment on the liquid film to obtain a perovskite film;

[0027] Wherein, the tetraphenylethylene monomer is selected from one or more of tetrakis(4-aminophenyl)ethylene (ETTA), tetrakis(4-formylphenyl)ethylene (ETBA), tetrakis(4-aminobiphenyl)ethylene (ETTBA), tetrakis(4-formylbiphenyl)ethylene (ETBC) and tetrakis(4-boronic acid phenyl)ethylene (TPEBA);

[0028] The perovskite film is an ABX3 type organic-inorganic hybrid perovskite film, wherein the perovskite precursor solution comprises organic cations, lead ions and halide ions for forming the ABX3 type organic-inorganic hybrid perovskite film, and the organic cations are selected from methylamine ions and / or formamidine ions;

[0029] ABX3 type perovskite film is a material with unique optical and electrical properties, and is widely used as a light absorption layer in solar cells. In the technical solution of the present invention, the perovskite precursor solution contains formamidinium ions (FA + ) and / or formamidinium ion (MA + ), lead ion (Pb 2+ ) and halide ions (X - , X can be Cl, Br, I, etc.), formamidinium ion (FA + ) and other organic cations, lead ions (Pb 2+ ) and halide ions (X - ) through coordination, forming an ABX3 type organic-inorganic hybrid perovskite structure, for example, FAPbX3, which has a high light absorption coefficient, long carrier diffusion length and adjustable band gap, and is a highly efficient photoelectric conversion material.

[0030] Based on the preparation method of the perovskite film of the present invention, by adding tetraphenylethylene monomers such as tetra(4-aminophenyl)ethylene as additives in the perovskite precursor solution, tetraphenylethylene monomers such as tetra(4-aminophenyl)ethylene can interact with organic cations (such as methylamine or formamidine) in the perovskite material through hydrogen bonds and π-π stacking interactions between tetraphenylethylene monomers, thereby enhancing the intermolecular force, effectively fixing the organic cations in the perovskite structure, and inhibiting the collapse of the perovskite crystal structure, thereby improving the photoelectric conversion efficiency and long-term stability of the perovskite solar cell.

[0031] In some embodiments, the content of the tetraphenylethylene monomer in the mixed solution is 0.01 mg / mL to 1 mg / mL.

[0032] In the technical solution of the embodiment of the present invention, controlling the additive tetraphenylethylene monomer within the above-mentioned range can more effectively enhance the intermolecular forces between the perovskite and the tetraphenylethylene monomer, and between the tetraphenylethylene monomer, thereby helping to form a more stable perovskite crystal structure and reduce lattice defects, thereby improving the uniformity and stability of the perovskite film.

[0033] In one embodiment, in order to further improve the stability of the perovskite film, the content of the tetraphenylethylene monomer in the mixed solution is 0.05 mg / mL to 0.5 mg / mL.

[0034] In one embodiment, in order to further improve the crystallinity and uniformity of the perovskite film, the concentration of the perovskite precursor solution is 0.5 mol / L to 2 mol / L based on ABX3.

[0035] In some embodiments, the solvent in the perovskite precursor solution is selected from N,N-dimethylformamide, dimethyl sulfoxide, or a mixture of the two in any proportion.

[0036] In the technical solution of the embodiment of the present invention, N,N-dimethylformamide and dimethyl sulfoxide have good solubility and volatility, can effectively dissolve the perovskite material, and volatilize quickly during the spin coating process, which is conducive to the rapid formation of the thin film and the formation of a uniform film layer.

[0037] In one embodiment, in order to form a more uniform perovskite film, the solvent in the perovskite precursor solution is a mixed solvent formed by mixing N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (1-4): (1-2).

[0038] In some embodiments, in step S2 , the mixed liquid is coated on the substrate by spin coating to form a liquid film, which is conducive to forming a uniform film layer.

[0039] In one embodiment, the spin coating speed is 2000 rpm to 6000 rpm, and the spin coating time is 5 s to 50 s.

[0040] In some embodiments, in the anti-solvent treatment, the anti-solvent is selected from one or more of toluene, chlorobenzene, cyclohexane, and ethyl acetate, including but not limited to the above anti-solvents.

[0041] In the technical solution of the embodiment of the present invention, the anti-solvent treatment uses solvents such as toluene, chlorobenzene, cyclohexane, ethyl acetate, etc. that are insoluble in the perovskite material, which is beneficial to quickly reduce the solvent concentration in the solution and promote the rapid precipitation and crystallization of the perovskite material.

[0042] In one embodiment, the anti-solvent treatment includes: dripping the anti-solvent onto the liquid film according to the volume ratio of the anti-solvent to the liquid film (2-4):1.

[0043] In the technical solution of the embodiment of the present invention, controlling the volume ratio of the anti-solvent (such as toluene, chlorobenzene or cyclohexane) to the liquid film (for example, the solvent is N,N-dimethylformamide or dimethyl sulfoxide) within the above range is beneficial to balance the rapid formation and uniform crystallization of the perovskite film and avoid film defects caused by too fast evaporation of the solvent.

[0044] In some embodiments, during the annealing process, the annealing temperature is 100° C. to 300° C., and the annealing time is 5 min to 60 min.

[0045] In the technical solution of the embodiment of the present invention, under the above-mentioned annealing conditions, it is beneficial to improve the crystallinity and density of the perovskite film, and enhance the photoelectric performance and stability of the film.

[0046] According to another aspect of the present invention, a perovskite film is provided, which is prepared according to the above method for preparing a perovskite film.

[0047] According to another aspect of the present invention, a solar cell is provided, comprising a light absorbing layer, wherein the light absorbing layer comprises the above perovskite film.

[0048] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0049] Example 1

[0050] A method for preparing a solar cell comprises the following steps:

[0051] Step 1: Clean the FTO glass substrate with acetone, isopropanol and deionized water in sequence, blow dry and set aside.

[0052] Step 2: Prepare a NiOx hole transport layer on a FTO glass substrate by magnetron sputtering and annealing, with a thickness of 30 nm, an annealing temperature of 300° C., and an annealing time of 30 min.

[0053] Step 3: Prepare 1.5 mol / L (FA 0.95 MA 0.05 ) 0.95 Cs 0.05 Pb(I 0.95 Br 0.05 )3 perovskite precursor solution. Specifically, weigh 232.8 mg FAI (iodine formamide), 7.98 mg MABr (methylammonium bromide), 19.49 mg CsI (cesium iodide), 27.53 mg PbBr2 (lead bromide), 676.6 mg PbI2 (lead iodide), 30.38 mg MACl (methylammonium chloride) and 0.2 mg tetrakis (4-aminophenyl) ethylene and place them in a mixing container, add 1 mL of a mixed solvent of DMF and DMSO (wherein the volume ratio of DMF to DMSO is 4:1) to the mixing container containing the above raw materials, and stir at room temperature for 2 hours to mix to obtain a mixed solution.

[0054] Step 4: Take 100 μL of the mixed solution on the hole transport layer, spin coat at 2000 rpm for 10 s, and spin coat at 5000 rpm for 40 s to form a liquid film. Take 200 μL of chlorobenzene as an anti-solvent and spin coat on the liquid film for 15 s. Then anneal the perovskite film at 100 °C on a hot stage for 30 minutes to form a perovskite light-absorbing layer with a thickness of 400 nm.

[0055] Step 5: The electron transport layer C60 layer and the buffer layer BCP layer are sequentially prepared on the perovskite light absorbing layer by vacuum evaporation method, with thicknesses of 40 nm and 5 nm respectively.

[0056] Step six, using vacuum evaporation method to prepare metal electrode gold on the BCP layer with a thickness of 100nm to obtain a solar cell.

[0057] Example 2

[0058] The only difference from Example 1 is that in step 3, the amount of tetrakis(4-aminophenyl)ethylene added is 0.05 mg.

[0059] Example 3

[0060] The only difference from Example 1 is that in step 3, the amount of tetrakis(4-aminophenyl)ethylene added is 0.5 mg.

[0061] Example 4

[0062] The only difference from Example 1 is that the tetraphenylethylene monomer tetrakis(4-aminophenyl)ethylene in step 3 is replaced by tetrakis(4-formylphenyl)ethylene.

[0063] Example 5

[0064] The only difference from Example 1 is that the tetraphenylethylene monomer tetrakis(4-aminophenyl)ethylene in step 3 is replaced by tetrakis(4-aminobiphenyl)ethylene.

[0065] Comparative Example 1

[0066] The only difference between the above method and Example 1 is that the tetraphenylethylene monomer tetrakis(4-aminophenyl)ethylene is not added in step three.

[0067] The perovskite solar cells prepared in the embodiment and the comparative example were performance tested, and their photoelectric conversion efficiency (PCE), fill factor (FF), open circuit voltage (Voc) and short circuit current (Jsc) are shown in Table 1 respectively; the PCE retention rate of the perovskite solar cells prepared in the embodiment and the comparative example after 500 hours at N2 conditions and 45±5°C was tested, and the results are shown in Table 1.

[0068] Table 1

[0069]

[0070]

[0071] As can be seen from Table 1, the perovskite film prepared by the method for preparing the perovskite film according to the embodiment of the present invention is used as a light absorption layer of a solar cell, and the obtained perovskite solar cell has a high open circuit voltage, short circuit current density and fill factor, and a high photoelectric conversion efficiency. After 500 hours, the photoelectric conversion efficiency still maintains more than 90% of its initial PCE.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a perovskite film, characterized in that: The steps include: Step S1, preparing a mixed solution including a perovskite precursor solution and a tetraphenylethylene monomer; Step S2, coating the mixed solution on a substrate to form a liquid film, and sequentially performing anti-solvent treatment and annealing treatment on the liquid film to obtain a perovskite film; Wherein, the tetraphenylethylene monomer is selected from one or more of tetrakis(4-aminophenyl)ethylene, tetrakis(4-formylphenyl)ethylene, tetrakis(4-aminobiphenyl)ethylene, tetrakis(4-formylbiphenyl)ethylene and tetrakis(4-boronic acid phenyl)ethylene; The perovskite film is an ABX3 type organic-inorganic hybrid perovskite film, and the perovskite precursor solution contains organic cations, lead ions and halide ions that form the ABX3 type organic-inorganic hybrid perovskite film, and the organic cations are selected from methylamine ions and / or formamidine ions.

2. The method for preparing a perovskite thin film according to claim 1, characterized in that: The content of the tetraphenylethylene monomer in the mixed solution is 0.01 mg / mL to 1 mg / mL.

3. The method for preparing a perovskite thin film according to claim 2, characterized in that: The content of the tetraphenylethylene monomer in the mixed solution is 0.05 mg / mL to 0.5 mg / mL.

4. The method for preparing a perovskite thin film according to any one of claims 1 to 3, characterized in that: Calculated in terms of ABX3, the concentration of the perovskite precursor solution is 0.5 mol / L to 2 mol / L.

5. The method for preparing a perovskite thin film according to any one of claims 1 to 3, characterized in that: The solvent in the perovskite precursor solution is selected from one of N,N-dimethylformamide and dimethyl sulfoxide or a mixture of the two in any proportion; Preferably, the solvent in the perovskite precursor solution is a mixed solvent formed by mixing N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (1-4):(1-2).

6. The method for preparing a perovskite thin film according to any one of claims 1 to 3, characterized in that: In the step S2, the mixed liquid is coated on the substrate by spin coating to form the liquid film; Preferably, the spin coating rotation speed is 2000 rpm to 6000 rpm, and the spin coating time is 5 s to 50 s.

7. The method for preparing a perovskite thin film according to any one of claims 1 to 3, characterized in that: In the anti-solvent treatment, the anti-solvent is selected from one or more of toluene, chlorobenzene, cyclohexane, and ethyl acetate.

8. The method for preparing a perovskite thin film according to any one of claims 1 to 3, characterized in that: In the annealing treatment, the annealing temperature is 100° C. to 300° C., and the annealing time is 5 min to 60 min.

9. A perovskite film, characterized in that: The perovskite film is prepared according to the method for preparing the perovskite film according to any one of claims 1 to 8.

10. A solar cell comprising a light absorbing layer, characterized in that: The light absorbing layer comprises the perovskite thin film according to claim 9.

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