Perovskite thin film, method for preparing the same, and perovskite battery

Abstract

The application discloses a perovskite thin film and a preparation method thereof and a perovskite battery, and belongs to the technical field of solar cells. The preparation method of the perovskite thin film comprises the following steps: dissolving betacyanin in a perovskite precursor solution to form a mixed solution; dropping the mixed solution onto a substrate; rotating the substrate with the mixed solution to form a coating on the substrate; and performing heat treatment to prepare the perovskite thin film. The preparation method can improve the light absorption capacity of the perovskite thin film, and the prepared perovskite thin film can improve the conversion efficiency of the perovskite battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a perovskite film, a preparation method thereof and a perovskite cell. BACKGROUND

[0002] At present, fossil energy such as coal and oil is still the main energy source in today's society. The combustion of fossil energy not only provides power but also produces a large amount of polluting substances, such as sulfur dioxide, nitrogen dioxide, carbon dioxide, carbon monoxide and dust particles, which seriously pollute the environment, cause ecological damage and harm our health. People are increasingly aware that, under the background of carbon peak and carbon neutralization, it is imperative to develop and utilize renewable clean energy. As an effective way to utilize solar energy resources, solar cells have become a research hotspot for researchers.

[0003] In the development process of solar cells, perovskite, as a highly efficient light-absorbing material, has extremely high light absorption coefficient, excellent carrier transport capacity, adjustable band gap and other photoelectric properties. Since it was first tried to be applied to photovoltaic power generation in 2009, its energy conversion efficiency has increased from 3.8% to 25.2% in just 10 years. The inventors of the present application found in their research that one of the effective ways to improve the conversion efficiency of perovskite cells is to improve the light absorption capacity of perovskite films, but how to improve the light absorption capacity of perovskite films is a technical problem. SUMMARY

[0004] The present application provides a perovskite film, a preparation method thereof and a perovskite cell. The preparation method can improve the light absorption capacity of the perovskite film, and the prepared perovskite film can improve the conversion efficiency of the perovskite cell.

[0005] The present application is implemented as follows:

[0006] In a first aspect, the present application provides a preparation method of a perovskite film, comprising:

[0007] dissolving betalain in a perovskite precursor solution to form a mixed solution;

[0008] dropping the mixed solution onto a substrate;

[0009] rotating the substrate with the mixed solution to form a coating on the substrate, and performing heat treatment to prepare a perovskite film.

[0010] In some embodiments, the betalain includes betacyanin and / or betaxanthin.

[0011] In some embodiments, the betalain contains a pigment stabilizer.

[0012] In some embodiments, the pigment stabilizer comprises flavonoids; optionally, the flavonoids comprise at least one of baicalin and baicalein.

[0013] In some embodiments, the perovskite precursor solution is selected from PbI2 and methylammonium iodide as solute, and at least one of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) as solvent.

[0014] In some embodiments, the substrate surface has a compact layer; optionally, the compact layer comprises any one of TiO2, SnO2, ZnO and NiO; optionally, the compact layer has a thickness of 200-400 nm.

[0015] Preferably, the compact layer is TiO2.

[0016] Preferably, the compact layer has a thickness of 300 nm.

[0017] In some embodiments, the heat treatment time is 10-30 min; optionally, the heat treatment time is 20 min.

[0018] In some embodiments, the preparation method comprises at least one of the following limitations:

[0019] First limitation: the substrate is FTO or ITO conductive glass;

[0020] Second limitation: the perovskite thin film has a thickness of 400-600 nm; optionally, the perovskite thin film has a thickness of 500 nm;

[0021] Third limitation: the mixed solution is dropped onto the substrate with the compact layer, and is left for 4-6 s before rotation;

[0022] Fourth limitation: the process conditions of the rotation comprise: first, spin coating at a speed of 400-600 rpm for 2-5 s, and then spin coating at a speed of 4000-6000 rpm for 25-35 s.

[0023] In a second aspect, the present application provides a perovskite thin film prepared by the preparation method of the perovskite thin film according to the first aspect.

[0024] In a third aspect, the present application provides a perovskite battery comprising the perovskite thin film according to the second aspect.

[0025] The present application has at least the following beneficial effects:

[0026] The preparation method of the perovskite thin film of the present application adds betanin to the perovskite precursor solution, and then performs dropping and rotation, so that the prepared perovskite thin film has better light absorption capacity.

[0027] The perovskite battery of the present application, including the perovskite thin film prepared by the preparation method of the perovski thin film of the present application, has good photoelectric conversion efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0029] Figure 1 The ultraviolet-visible light absorption rate curve of the perovskite thin film of Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0030] The embodiments of the present application will be described in detail below with reference to the embodiments, but those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the embodiments, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be obtained by market purchase.

[0031] The following is directed to the perovskite thin film and its preparation method and the perovskite battery of the embodiments of the present application.

[0032] Specifically explained:

[0033] In a first aspect, the present application provides a preparation method of a perovskite thin film, comprising:

[0034] Dissolving betalain in a perovskite precursor solution to form a mixed solution;

[0035] Adding the mixed solution dropwise to a substrate;

[0036] Rotating the substrate with the mixed solution dropwise to form a coating on the substrate, and after heat treatment, a perovskite thin film is prepared.

[0037] The solute selected for the perovskite precursor solution is PbI2 and methylammonium iodide (abbreviated as MAI in English), and the solvent is at least one of N,N-dimethylformamide (abbreviated as DMF in English) and dimethyl sulfoxide (abbreviated as DMSO in English).

[0038] Optionally, the substrate is FTO or ITO conductive glass.

[0039] In some embodiments, the substrate surface has a dense layer. Under the action of the dense layer, the mixed solution can be uniformly and stably distributed on the surface of the dense layer.

[0040] Optionally, the dense layer comprises any one of TiO2, SnO2, ZnO and NiO. Optionally, the thickness of the dense layer is 200-400 nm, for example, 200 nm, 250 nm, 300 nm, 350 nm or 400 nm.

[0041] Further, the mixed solution is dropped onto the substrate with the dense layer, and then placed for 4-6 s before rotation. Exemplarily, the process conditions of rotation include: first spin coating at a speed of 400-600 rpm for 2-5 s, and then spin coating at a speed of 4000-6000 rpm for 25-35 s. First spin coating at a slower speed for a shorter time, and then spin coating at a faster speed for a longer time, can make the thickness of the spin-coated coating more uniform.

[0042] In some embodiments, the process conditions of rotation include: first spin coating at a speed of 500 rpm for 3 s, and then spin coating at a speed of 5000 rpm for 30 s.

[0043] The inventors of the present application found in research that, under the same conditions, the perovskite precursor solution added with betalain has better light absorption capacity than the perovskite precursor solution without betalain, and the perovskite thin film prepared has a significantly stronger light absorption intensity in the range of 400-480 nm. The betalain includes betacyanin and / or betaxanthin. The thickness of the perovskite thin film is 400-600 nm, for example, 400 nm, 500 nm or 600 nm.

[0044] The betalain can be self-prepared or purchased on the market. It should be noted that the betalain can be extracted from plants or artificially synthesized.

[0045] Exemplarily, the process steps of artificially synthesized betalain include: tyrosine is formed into betalaline under the action of tyrosinase and 4,5-dopa dioxygenase, and betalaline is reacted with amino acid or amine to form betaxanthin; betalaline is reacted to form betanidin, and then glycosylated by glycosyltransferase to form betacyanin. The description of the betalain biosynthesis pathway can be found in the paper (Fujian Agriculture and Forestry University, Master's Thesis: Effects of Red-Blue Compound Light on Betalain Synthesis and Cryptochrome Gene Expression in Amaranth Seedlings).

[0046] Further, a coating layer is formed on the substrate, and heat treatment is performed at a temperature of 100-120℃. The quality of the perovskite thin film prepared by heat treatment at this temperature is better, and the nucleation and crystal growth are better. Optionally, the heat treatment time is 10-30min, for example, 10min, 15min, 20min, 25min or 30min. Illustratively, the heat treatment temperature is 100℃, 105℃, 110℃, 115℃ or 120℃.

[0047] The inventors of the present application found in research that the heat stability of the natural beet pigment extracted from plants is poor, and the activity is affected to a certain extent under high temperature conditions. Therefore, by adding a pigment stabilizer to the natural beet pigment extracted from plants, or adding a pigment stabilizer to the artificially synthesized beet pigment, the stability of the beet pigment in the heat treatment is good, and the destruction of the beet pigment in the heat treatment of the coating layer is avoided to affect the improvement of the light absorption capacity of the perovskite thin film.

[0048] Among them, the pigment stabilizer includes flavonoids. Optionally, the flavonoids include at least one of baicalin and baicalein. Illustratively, the mass ratio of the pigment stabilizer to the beet pigment is 1-3:7-9, for example, 1:9, 2:8 or 3:7.

[0049] In a second aspect, the present application provides a perovskite thin film prepared by the preparation method of the perovskite thin film of the first aspect. The perovskite thin film has good light absorption capacity and strong light absorption intensity in the range of 400-480nm.

[0050] In a third aspect, the present application provides a perovskite battery including the perovskite thin film of the second aspect. The perovskite battery has good photoelectric conversion efficiency.

[0051] The perovskite thin film and its preparation method and the perovskite battery of the present application are further described in detail below in conjunction with examples.

[0052] Example 1

[0053] The present embodiment provides a preparation method of a perovskite thin film, which includes the following steps:

[0054] 1) Dissolve the beet pigment containing baicalein in the perovskite precursor solution, stir uniformly to obtain a mixed solution. The concentration of the perovskite precursor solution is 1.3mol / L, the molar ratio of PbI2 and MAI is 1:1.3, the volume ratio of DMF and DMSO is 3:1, the mass fraction of the beet pigment in the perovskite precursor solution is 2%, and the mass ratio of baicalein to beet pigment is 1:9. The beet pigment is betaxanthin.

[0055] 2) The mixed solution obtained in step 1) is added dropwise to a substrate with a 300 nm thick TiO2 dense layer, placed for 3 seconds, spin-coated at a speed of 500 rpm for 3 seconds, and then spin-coated at a speed of 5000 rpm for 30 seconds.

[0056] 3) After spin-coating, the substrate is transferred to a high-temperature heating table in a low-humidity glove box for heat treatment at a temperature of 120°C for 20 min to produce a perovskite film. The atmosphere in the low-humidity glove box is nitrogen, and the humidity is maintained at 2%-3%.

[0057] Example 2

[0058] The present example provides a method for preparing a perovskite film, comprising the following steps:

[0059] 1) Dissolve the betalain in the perovskite precursor solution and stir uniformly to obtain a mixed solution. The concentration of the perovskite precursor solution is 1.3 mol / L, the molar ratio of PbI2 and MAI is 1:1.3, the volume ratio of DMF and DMSO is 3:1, the mass fraction of betalain in the perovskite precursor solution is 1%, and the mass ratio of baicalein to betalain is 2:8.

[0060] 2) The mixed solution obtained in step 1) is added dropwise to a substrate with a 300 nm thick TiO2 dense layer, placed for 3 seconds, spin-coated at a speed of 500 rpm for 3 seconds, and then spin-coated at a speed of 5000 rpm for 30 seconds.

[0061] 3) After spin-coating, the substrate is transferred to a high-temperature heating table in a low-humidity glove box for heat treatment at a temperature of 120°C for 20 min to produce a perovskite film. The atmosphere in the low-humidity glove box is nitrogen, and the humidity is maintained at 2%-3%.

[0062] Example 3

[0063] The present example provides a method for preparing a perovskite film, comprising the following steps:

[0064] 1) Dissolve the betalain in the perovskite precursor solution and stir uniformly to obtain a mixed solution. The concentration of the perovskite precursor solution is 1.3 mol / L, the molar ratio of PbI2 and MAI is 1:1.3, the volume ratio of DMF and DMSO is 3:1, the mass fraction of betalain in the perovskite precursor solution is 3%, and the mass ratio of baicalein to betalain is 3:7.

[0065] 2) The mixed solution obtained in step 1) is added dropwise to a substrate with a 300 nm thick TiO2 dense layer, placed for 3 seconds, spin-coated at a speed of 500 rpm for 3 seconds, and then spin-coated at a speed of 5000 rpm for 30 seconds.

[0066] 3) After spin-coating, the substrate is transferred to a high-temperature heating table in a low-humidity glove box for heat treatment at a temperature of 120°C for 20 min to form a perovskite film. The atmosphere in the low-humidity glove box is nitrogen, and the humidity is maintained at 2%-3%.

[0067] Comparative Example 1

[0068] The present comparative example provides a method for preparing a perovskite film, which comprises the following steps:

[0069] 1) A perovskite precursor solution is provided. The concentration of the perovskite precursor solution is 1.3 mol / L, the molar ratio of PbI2 and MAI is 1:1.3, and the volume ratio of DMF and DMSO is 3:1.

[0070] 2) The perovskite precursor solution of step 1) is added dropwise to a substrate with a 300 nm thick TiO2 dense layer, placed for 3 seconds, spin-coated at a speed of 500 rpm for 3 seconds, and then spin-coated at a speed of 5000 rpm for 30 seconds.

[0071] 3) After spin-coating, the substrate is transferred to a high-temperature heating table in a low-humidity glove box for heat treatment at a temperature of 120°C for 20 min to form a perovskite film. The atmosphere in the low-humidity glove box is nitrogen, and the humidity is maintained at 2%-3%.

[0072] Test Example 1

[0073] The ultraviolet-visible light absorption of the perovskite films of Example 1 and Comparative Example 1 is detected by an ultraviolet-visible spectrophotometer, and the results are shown in Figure 1 . The perovskite film after adding the pigment is the perovskite film of Example 1, and the original perovskite film refers to the perovskite film of Comparative Example 1.

[0074] From Figure 1 it can be seen that the perovskite film of Example 1 prepared by adding beet pigment has better light absorption capacity compared to the perovskite film of Comparative Example 1 prepared without adding beet pigment, and the light absorption intensity in the range of 400-480 nm is significantly enhanced.

[0075] Test Example 2

[0076] The perovskite thin films of Example 1 and Comparative Example 1 were prepared into perovskite solar cells under the same conditions, respectively, and the photoelectric current and voltage of the prepared cell devices were tested under the same conditions. The test results are shown in Table 1. The cell structure includes a cathode glass substrate, a dense layer, a perovskite light absorption layer, a hole transport layer and an anode which are sequentially stacked.

[0077] Table 1. Cell device performance test results

[0078]

[0079] As can be seen from the results in Table 1, the perovskite solar cell prepared from the perovskite thin film of Example 1 has higher open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency than the perovskite solar cell prepared from the perovskite thin film of Comparative Example 1. It is shown that the perovskite thin film prepared by the preparation method of the perovskite thin film of the present application is beneficial to improve the conversion efficiency of the perovskite solar cell.

[0080] The above only describes specific embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a perovskite thin film, characterized by, The preparation method comprises the following steps: dissolving betalain in perovskite precursor solution to form a mixed solution; the betalain contains a pigment stabilizer; the pigment stabilizer comprises flavonoids, and the flavonoids comprise at least one of baicalin and baicalein; dropping the mixed solution onto a substrate; rotating the substrate with the mixed solution to form a coating on the substrate, and performing heat treatment to prepare a perovskite film.

2. The method of claim 1, wherein the perovskite thin film is prepared by a method comprising: The betalain comprises betacyanin and / or betaxanthin.

3. The method of claim 1 or 2, wherein the perovskite thin film is prepared by a method comprising the steps of: The perovskite precursor solution is prepared by using PbI2 and methyl amine iodide as solutes and at least one of N,N-dimethylformamide and dimethyl sulfoxide as a solvent.

4. The method for preparing perovskite thin films according to claim 1 or 2, characterized in that, The substrate surface has a compact layer.

5. The method of claim 4, wherein the perovskite thin film is prepared by a process comprising: The compact layer comprises any one of TiO2, SnO2, ZnO and NiO.

6. The method for preparing perovskite thin films according to claim 4, characterized in that, The thickness of the compact layer is 200-400 nm.

7. The method for preparing perovskite thin films according to claim 1 or 2, characterized in that, The heat treatment temperature is 100-120 ℃.

8. The method for preparing perovskite thin films according to claim 7, characterized in that, The heat treatment time is 10-30 min. 9.The method of claim 1 or 2, wherein The preparation method comprises at least one of the following limitations: first limitation: the substrate is FTO or ITO conductive glass; second limitation: the thickness of the perovskite film is 400-600 nm; third limitation: the mixed solution is dropped onto the substrate with the compact layer, and then is left for 4-6 s before rotation; fourth limitation: the process conditions of the rotation comprise the following steps: first, spin coating at a speed of 400-600 rpm for 2-5 s, and then spin coating at a speed of 4000-6000 rpm for 25-35 s.

10. A perovskite thin film, characterized by, The perovskite film is prepared by the preparation method of any one of claims 1-9.

11. A perovskite cell, characterized in that, The perovskite film comprises the perovskite film of claim 10.

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