Perovskite thin film, preparation method thereof and perovskite device

Abstract

The invention provides a perovskite thin film, a preparation method thereof and a perovskite device. The preparation method of the perovskite thin film comprises the following steps: coating the surface of a substrate with a perovskite precursor solution to obtain a perovskite wet film; placing the perovskite wet film in a steam environment, and crystallizing to obtain a dry film; and annealing the dry film in the air to obtain the perovskite thin film, steam in the steam environment comprises DMSO and an amine compound. According to the method, the perovskite wet film is crystallized in the steam environment containing DMSO and the amine compound, the preparation time of the perovskite film is remarkably shortened through the subsequent annealing process, and the perovskite film with high crystal quality is prepared without the treatment conditions of high temperature, anti-solvent and the like.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technologies, specifically to solar devices, and particularly to a perovskite thin film, a preparation method thereof, and a perovskite device. Background Art

[0002] Perovskite solar cells have become a research hotspot in the photovoltaic field due to their high light absorption coefficient, adjustable bandgap, and low-temperature solution processability. The conventional preparation methods of perovskite thin films rely on anti-solvent-assisted spin coating and long-time annealing (≥30 minutes), with complex processes, high energy consumption, and difficulty in scaling up. Moreover, high-temperature annealing is prone to cause perovskite decomposition and interface damage. Although the thermal crystallization method for preparing perovskite thin films can shorten the annealing time, there are still problems such as insufficient film crystallinity, many grain boundary defects, and residual non-perovskite phases, resulting in significantly lower device efficiency.

[0003] CN117642038A discloses a method for fabricating a perovskite layer, a perovskite battery, a battery module, and a photovoltaic system, including the following steps: providing a substrate for fabricating the perovskite layer; using a perovskite precursor solution to fabricate a perovskite precursor wet film on the substrate; performing vacuum drying treatment on the perovskite precursor wet film to form a perovskite precursor dry film; performing thermal solvent annealing on the perovskite precursor dry film to form a perovskite layer. This method not only requires vacuum drying treatment of the wet film during thin film preparation but also requires thermal solvent annealing of the dry film for 10 min - 15 min, with a complex process and long time consumption.

[0004] CN115360307A discloses a method for preparing a thin film, an optoelectronic device, and a display device, including the following steps: a) placing a perovskite precursor solution on the surface of a substrate to obtain a perovskite precursor solution thin film; b) performing vacuum anti-solvent annealing on the perovskite precursor solution thin film obtained in step a) to obtain a perovskite thin film. After preparing the perovskite precursor solution thin film, this method needs to first perform vacuum treatment on it to obtain a dry film, then add an anti-solvent to vaporize for 0.5 min - 2 min and then anneal for 3 min - 60 min, still unable to avoid the disadvantages of complex operation and long time consumption.

[0005] Therefore, it is of great significance to provide a new method for preparing perovskite thin films that combines high efficiency, rapid crystallization, and does not require treatment conditions such as anti-solvents and vacuum drying. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a perovskite thin film, a preparation method thereof and a perovskite device. In the present invention, the perovskite wet film is placed in a vapor environment containing DMSO (dimethyl sulfoxide) and an amine compound for crystallization, and after subsequent annealing process, the preparation time of the perovskite thin film is significantly shortened, and high-crystallinity perovskite thin film can be obtained without high-temperature and anti-solvent treatment conditions.

[0007] To achieve the object of the present invention, the following technical solutions are adopted:

[0008] In the first aspect, the present invention provides a method for preparing a perovskite thin film, the preparation method comprising:

[0009] Coating a perovskite precursor solution on the surface of a substrate to obtain a perovskite wet film; placing the perovskite wet film in a vapor environment for crystallization to obtain a dry film; annealing the dry film in air to obtain the perovskite thin film; annealing the dry film in air to obtain the perovskite thin film;

[0010] The vapor in the vapor environment comprises DMSO and an amine compound.

[0011] In the present invention, the perovskite wet film is placed in a vapor environment containing DMSO and an amine compound for crystallization. Among them, DMSO and the amine compound cooperate with each other to regulate the nucleation rate of perovskite grains, promote the directional growth of grains, and reduce pinhole defects. In addition, DMSO in the vapor environment can also regulate the evaporation rate of the solvent and the crystallization activation energy in the perovskite wet film, optimize the growth of perovskite grain boundaries, thereby reducing the non-radiative recombination of the thin film. After subsequent annealing process, the preparation time of the perovskite thin film is significantly shortened, and high-crystallinity perovskite thin film can be obtained without high-temperature and anti-solvent treatment conditions.

[0012] Preferably, in the vapor environment, the mass ratio of DMSO to the amine compound is 1000:(0.5 - 5).

[0013] Preferably, in the vapor environment, the total volume concentration of DMSO and the amine compound is 0.01 g / L - 10 g / L.

[0014] Preferably, the amine compound comprises any one or at least two combinations of tetra-tert-butylpyridine, methylamine, urea, ethylamine, phenethylamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, cyclohexylamine or diphenylamine.

[0015] Preferably, the crystallization time is 10 s - 3 min.

[0016] Preferably, the annealing temperature is 80°C - 300°C.

[0017] Preferably, the annealing time is 1 min - 10 min.

[0018] Preferably, the steam environment is formed by the following method:

[0019] In a closed environment, a mixed solvent containing DMSO and an amine compound is dropped onto a hot stage, and the mixed solvent vaporizes to form the steam environment.

[0020] Preferably, the temperature of the hot stage is 80°C - 200°C.

[0021] In a second aspect, the present invention provides a perovskite thin film, which is prepared by the preparation method described in the first aspect.

[0022] The perovskite thin film prepared by the preparation method provided by the present invention has higher crystallization quality, can obtain larger grain size, and is more beneficial to the improvement of the efficiency of perovskite devices based on the perovskite thin film of the present invention.

[0023] Preferably, in the perovskite thin film, the average size of the grains is 0.5 mm - 5 mm.

[0024] In a third aspect, the present invention provides a perovskite device, which includes the perovskite thin film described in the second aspect.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) In the present invention, the perovskite wet film is crystallized in a steam environment containing DMSO and an amine compound, and through subsequent annealing process, the preparation time of the perovskite thin film is significantly shortened, and high-temperature and anti-solvent treatment conditions are not required, that is, a perovskite thin film with high crystallization quality is prepared.

[0027] (2) The perovskite thin film provided by the present invention has higher crystallization quality, can obtain larger grain size, and is more beneficial to the improvement of the efficiency of perovskite devices based on the perovskite thin film of the present invention. Description of the Drawings

[0028] Figure 1 is a schematic diagram of the preparation process of the perovskite thin film in Example 1.

[0029] Among them, 1 - steam environment; 2 - substrate; 3 - perovskite wet film. Detailed Embodiments

[0030] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusion.

[0032] In a specific embodiment, the present invention provides a method for preparing a perovskite thin film, and the preparation method includes:

[0033] Coating a perovskite precursor solution on the surface of a substrate to obtain a perovskite wet film; placing the perovskite wet film in a steam environment for crystallization to obtain a dry film; annealing the dry film in air to obtain the perovskite thin film; annealing the dry film in air to obtain the perovskite thin film;

[0034] The steam in the steam environment includes DMSO and an amine compound.

[0035] The present invention places the perovskite wet film in a steam environment containing DMSO and an amine compound for crystallization. Among them, DMSO and the amine compound cooperate with each other to be able to regulate the nucleation rate of perovskite grains, promote the directional growth of grains, and reduce pinhole defects. In addition, DMSO in the steam environment can also regulate the evaporation rate of the solvent and the crystallization activation energy in the perovskite wet film, optimize the growth of perovskite grain boundaries, thereby reducing non-radiative recombination of the thin film. After subsequent annealing processes, the preparation time of the perovskite thin film is significantly shortened, and high-crystallinity perovskite thin films can be prepared without high-temperature and anti-solvent treatment conditions.

[0036] The amine compound referred to in the present invention means a compound that contains an amino group in the molecule and can be vaporized at 200 °C.

[0037] In the present invention, the mass ratio of DMSO to the amine compound affects the crystallization rate and surface passivation effect of the perovskite thin film. If the mass ratio is too large, that is, the proportion of DMSO in the steam environment is too large, the surface passivation effect of the thin film is not obvious and pores are likely to appear. If the mass ratio is too small, that is, the proportion of the amine compound in the steam environment is too large, crystallization is difficult, it is difficult to form a perovskite structure, and a perovskite thin film cannot be prepared.

[0038] In some embodiments, in the steam environment, the mass ratio of DMSO to the amine compound is 1000:(0.5 - 5), for example, it can be 1000:0.5, 1000:1, 1000:1.5, 1000:2, 1000:2.5, 1000:3, 1000:3.5, 1000:4, 1000:4.5, or 1000:5, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Preferably, it is 1000:(1 - 2.5).

[0039] In the present invention, the total volume concentration of DMSO and the amine compound affects the crystallization rate and crystallization quality of the perovskite film. If the volume concentration is too high, the crystallization rate slows down and it is difficult to form a perovskite structure. If the volume concentration is too low, the crystallization rate is too fast, and the grain size in the obtained perovskite film is too small and there are many defects.

[0040] In some embodiments, in the steam environment, the total volume concentration of DMSO and the amine compound is 0.01 g / L - 10 g / L, for example, it can be 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, or 10 g / L, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Preferably, it is 0.05 g / L - 5 g / L.

[0041] In some embodiments, the amine compound includes any one or a combination of at least two of tetra-tert-butylpyridine, methylamine, urea, ethylamine, phenethylamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, cyclohexylamine, or diphenylamine. Typical but non-limiting combinations include: the combination of tetra-tert-butylpyridine and methylamine, the combination of urea and ethylamine, the combination of phenethylamine and ethylenediamine, the combination of dimethylamine and trimethylamine, the combination of triethylamine and propylamine, the combination of isopropylamine and tripropylamine, the combination of triethanolamine and butylamine, the combination of isobutylamine and tert-butylamine, the combination of hexylamine and octylamine, or the combination of aniline and cyclohexylamine.

[0042] In some embodiments, the crystallization time is 10 s - 3 min, for example, it can be 10 s, 12 s, 14 s, 16 s, 18 s, 20 s, 22 s, 24 s, 26 s, 28 s, 30 s, 1 min, 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 2.5 min, or 3 min, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Preferably, it is 10 s - 30 s.

[0043] In some embodiments, the annealing temperature is 80°C - 300°C. For example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C or 300°C, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0044] In some embodiments, the annealing time is 1 min - 10 min. For example, it can be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0045] In some embodiments, the vapor environment is formed by the following method:

[0046] In a closed environment, a mixed solvent containing DMSO and an amine compound is dropped onto a hot stage, and the mixed solvent vaporizes to form the vapor environment.

[0047] In some embodiments, the temperature of the hot stage is 80°C - 200°C. For example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0048] In the preparation method provided by the present invention, the material of the substrate and the preparation method of the perovskite precursor solution are not specifically limited. Exemplarily, the material of the substrate includes but is not limited to any one of FTO (fluorine-doped tin oxide), ITO (indium tin oxide), or ITZO (indium tin zinc oxide); the preparation method of the perovskite precursor solution includes:

[0049] In a solvent, a perovskite precursor is dissolved to prepare a perovskite precursor solution.

[0050] The perovskite precursor includes any one or a combination of at least two of FAPbBr3, FAPbI3, CsPbBr3, CsPbI3, MAPbBr3, MAPbI3, FAPbCl3, CsPbCl3, MAPbCl3, FASnBr3, FASnI3, CsSnBr3, CsSnI3, MASnBr3, MASnI3, FASnCl3, CsSnCl3, MASnCl3, MACl, PbI2, PbCl2.

[0051] In some embodiments, the perovskite precursor solution further includes MACl (methylammonium chloride).

[0052] In some embodiments, the concentration of the perovskite precursor solution is 0.5 M - 2 M, for example, it can be 0.5 M, 0.7 M, 0.9 M, 1.1 M, 1.3 M, 1.5 M, 1.7 M, 1.8 M, or 2 M, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0053] In another specific embodiment, the present invention provides a perovskite thin film, which is prepared by the preparation method described in the foregoing specific embodiment.

[0054] The perovskite thin film prepared by the preparation method provided by the present invention has higher crystallization quality, can obtain larger grain sizes, and is more conducive to improving the efficiency of perovskite devices based on the perovskite thin film of the present invention.

[0055] In some embodiments, in the perovskite thin film, the average size of the grains is 0.5 mm - 5 mm, for example, it can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0056] In yet another specific embodiment, the present invention provides a perovskite device, which includes the perovskite thin film described in the foregoing another specific embodiment.

[0057] Example 1

[0058] This example provides a method for preparing a perovskite thin film. The schematic diagram of the preparation process is as Figure 1 shown, and the preparation method includes:

[0059] (1) Prepare a perovskite wet film: Prepare a 0.7 M perovskite precursor solution of the FA 0.73 MA 0.18 Cs 0.09 PbI3 component. Add MACl and PbI2 to the solution to make their concentrations in the solution 0.7 M; Drop the perovskite precursor solution onto the ITO substrate 2 preheated at 60 °C. After the solution is completely spread, a perovskite wet film 3 is formed.

[0060] (2) Preparation of perovskite thin film: A mixed solvent of DMSO and phenethylamine with a mass ratio of 1000:1 was dropped on a hot plate at 150 °C in a container to form a vapor environment 1. In the vapor environment 1, the total volume concentration of DMSO and phenylenediamine was 1 g / L; the perovskite wet film 3 was transferred to the vapor environment 1 for crystallization for 30 s to obtain a dry film; after crystallization, it was annealed in air on a hot plate at 100 °C for 2 min to obtain a perovskite thin film.

[0061] Example 2

[0062] This example provides a method for preparing a perovskite thin film, and the preparation method includes:

[0063] (1) Preparation of perovskite wet film: Prepare a perovskite precursor solution of 1.5M FA 0.73 MA 0.18 Cs 0.09 PbI3 component. MACl and PbI2 were added to the solution so that their concentrations in the solution were 1.5M; the perovskite precursor solution was spin-coated on the ITO substrate at 4000 rpm. After the solution was completely spread, a perovskite wet film was formed.

[0064] (2) Preparation of perovskite thin film: A mixed solvent of DMSO and methylamine with a mass ratio of 1000:1.5 was dropped on a hot plate at 80 °C in a container to form a vapor environment. In the vapor environment, the total volume concentration of DMSO and methylamine was 0.05 g / L; the perovskite wet film was transferred to the vapor environment for crystallization for 10 s to obtain a dry film; after crystallization, it was annealed in air on a hot plate at 150 °C for 1 min to obtain a perovskite thin film.

[0065] Example 3

[0066] This example provides a method for preparing a perovskite thin film, and the preparation method includes:

[0067] (1) Preparation of perovskite wet film: Prepare a perovskite precursor solution of 0.7M FA 0.73 MA 0.18 Cs 0.09 PbI3 component; the perovskite precursor solution was drop-coated on a substrate preheated at 55 °C. After the solution was completely spread, a perovskite wet film was formed.

[0068] (2) Preparation of perovskite thin film: A mixed solvent of DMSO and aniline with a mass ratio of 1000:3 was dropped on a hot plate at 200 °C in a container to form a vapor environment. In the vapor environment, the total volume concentration of DMSO and triethylamine was 4 g / L; the perovskite wet film was transferred to the vapor environment for crystallization for 1 min to obtain a dry film; after crystallization, it was annealed in air on a hot plate at 300 °C for 3 min to obtain a perovskite thin film.

[0069] Example 4

[0070] This example provides a method for preparing a perovskite thin film, and the preparation method includes:

[0071] (1) Prepare a perovskite wet film: Prepare a perovskite precursor solution with a composition of 0.7 M FAPbI3; Drop the perovskite precursor solution onto a substrate preheated to 60 °C, and after the solution is completely spread, a perovskite wet film is formed.

[0072] (2) Prepare a perovskite thin film: Drop a mixed solvent of DMSO and butylamine with a mass ratio of 1000:2 onto a hot plate at 200 °C in a container to form a vapor environment. In this vapor environment, the total volume concentration of DMSO and butylamine is 3 g / L; Transfer the perovskite wet film to the vapor environment for crystallization, and the crystallization time is 40 s to obtain a dry film; After crystallization, anneal on a hot plate at 200 °C in air for 1.5 min to obtain a perovskite thin film.

[0073] Example 5

[0074] This example provides a method for preparing a perovskite thin film. Compared with Example 1, except that the mass ratio of DMSO to phenethylamine is 1000:0.05, the rest are the same as in Example 1.

[0075] Example 6

[0076] This example provides a method for preparing a perovskite thin film. Compared with Example 1, except that the mass ratio of DMSO to phenethylamine is 1000:7.5, the rest are the same as in Example 1.

[0077] Example 7

[0078] This example provides a method for preparing a perovskite thin film. Compared with Example 1, except that in the vapor environment, the total volume concentration of DMSO and phenethylamine is 15 g / L, the rest are the same as in Example 1.

[0079] Comparative Example 1

[0080] This comparative example provides a method for preparing a perovskite thin film. Compared with Example 1, except that the perovskite thin film crystallizes in an air environment, the rest are the same as in Example 1.

[0081] Comparative Example 2

[0082] This comparative example provides a method for preparing a perovskite thin film. Compared with Example 1, except that the perovskite thin film crystallizes in an Ar atmosphere, the rest are the same as in Example 1.

[0083] Comparative Example 3

[0084] This comparative example provides a method for preparing a perovskite thin film. Compared with Example 1, except that the vapor environment only contains DMSO with a volume concentration of 1 g / L, the rest are the same as in Example 1.

[0085] Comparative Example 4

[0086] This comparative example provides a method for preparing a perovskite thin film. Compared with Example 1, except that the vapor environment only contains phenethylamine with a volume concentration of 1 g / L, the rest are the same as in Example 1.

[0087] Performance test:

[0088] The grain size of the perovskite thin films prepared in all the above examples and comparative examples was tested by optical microscopy and scanning electron microscopy, and the test results are shown in Table 1.

[0089] The perovskite thin films prepared in all the above examples and comparative examples were assembled into perovskite devices with the structure of ITO / SnO2 / perovskite thin film / spiro-OMeTAD / Ag, and the efficiency of the corresponding perovskite devices was tested under the condition of a xenon lamp simulated light source AM1.5G, and the test results are shown in Table 1.

[0090] Table 1

[0091] Grain size / mm Efficiency / % Example 1 3 24 Example 2 2.5 23 Example 3 2.3 21 Example 4 2 19 Example 5 1.6 17.5 Example 6 1.1 16 Example 7 1.5 16.5 Comparative Example 1 0.2 12 Comparative Example 2 0.1 10 Comparative Example 3 1 13.5 Comparative Example 4 0.7 12.5

[0092] According to the test results in Table 1, by crystallizing the perovskite wet film in a vapor environment containing DMSO and an amine compound, the present invention significantly shortens the preparation time of the perovskite thin film, and does not require high-temperature and anti-solvent treatment conditions, that is, a perovskite thin film with high crystal quality is prepared, further improving the efficiency of the assembled perovskite device. The grain size in the perovskite thin films provided in Examples 1-4 is above 2 mm, and the conversion rate of the assembled perovskite device is above 19%.

[0093] In Comparative Examples 1 and 2, crystallization was carried out in air or an Ar environment, and the grain size of the prepared perovskite thin film decreased significantly to below 0.2 mm, and the efficiency of the assembled perovskite device could only reach 12%.

[0094] According to the test results of Comparative Examples 3 and 4, if the vapor environment only contains DMSO or only contains an amine compound, it is impossible to effectively promote the directional growth of grains, reduce pinhole defects, optimize the growth of perovskite grain boundaries, reduce the density of defect states, thereby reducing non-radiative recombination of the thin film and preparing a perovskite thin film with high crystal quality.

[0095] The applicant declares that the above is only a specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing a perovskite thin film, characterized in that, The preparation method includes: Coating a perovskite precursor solution on the surface of a substrate to obtain a perovskite wet film; placing the perovskite wet film in a vapor environment for crystallization to obtain a dry film; annealing the dry film in air to obtain the perovskite thin film; The vapor in the vapor environment includes DMSO and an amine compound.

2. The preparation method according to claim 1, characterized in that, In the vapor environment, the mass ratio of DMSO to the amine compound is 1000:(0.5 - 5); And / or, in the vapor environment, the total volume concentration of DMSO and the amine compound is 0.01 g / L - 10 g / L.

3. The preparation method according to claim 1 or 2, characterized in that, The amine compound includes any one or a combination of at least two of tetra-tert-butylpyridine, methylamine, urea, ethylamine, phenethylamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, cyclohexylamine, or diphenylamine.

4. The preparation method according to any one of claims 1-3, characterized in that, The crystallization time is 10 s - 3 min.

5. The preparation method according to any one of claims 1-4, characterized in that, The annealing temperature is 80°C - 300°C; And / or, the annealing time is 1 min - 10 min.

6. The preparation method according to any one of claims 1-5, characterized in that, The vapor environment is formed by the following method: In a closed environment, dropping a mixed solvent containing DMSO and an amine compound on a hot stage, and the mixed solvent vaporizes to form the vapor environment.

7. The preparation method according to claim 6, characterized in that, The temperature of the hot stage is 80°C - 200°C.

8. A perovskite thin film, characterized in that, The perovskite thin film is prepared by the preparation method according to any one of claims 1 - 7.

9. The perovskite thin film according to claim 8, wherein, In the perovskite thin film, the average grain size is 0.5 mm - 5 mm.

10. A perovskite device, characterized in that, The perovskite device includes the perovskite thin film according to claim 8 or 9.

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