Perovskite thin film and preparation method and use thereof

Abstract

The present application relates to a kind of perovskite thin film and its preparation method and use, the preparation method will thiocarbamide as the additive of perovskite precursor liquid, then by spin coating and annealing to the perovskite precursor liquid, obtain the perovskite thin film.The present application is by adding thiocarbamide, utilize its polar and high boiling point nature, solve the film cavity problem caused by solvent retention in perovskite thin film nucleation process, improve the contact condition of perovskite thin film bottom and conductive substrate, to realize the regulation of thin film crystallization process, using the preparation method can obtain the perovskite thin film with less hole, high crystallinity and uniformity, the fill factor of solar cell based on the perovskite thin film can reach 0.73, and photoelectric conversion efficiency can reach 15.6%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of solar cells, and relates to a perovskite thin film and a preparation method and use thereof. BACKGROUND

[0002] With the development of the times and the progress of science and technology, the demand for energy by mankind has risen sharply, but non-renewable energy not only has limited production, but also causes serious environmental damage, which forces people to seek cleaner energy, among which photovoltaic power generation is a new choice with great development potential. Since the twenty-first century, more and more researchers have begun to focus on organic-inorganic hybrid perovskite materials and apply them in solar cells. As a new type of solar cell material with many excellent properties, it has rapidly developed into a "new star" in the field of new energy. In recent years, the related research of metal halide hybrid perovskite solar cells has become a hot spot in the field. At present, the highest conversion efficiency of perovskite solar cells certified by authoritative agencies has broken through 25%, which is much higher than the conversion efficiency of traditional thin-film solar cells and comparable to the efficiency of the most commercially available crystalline silicon solar cells. In addition to being used in solar cells, it also has a very broad prospect in the fields of light-emitting diodes, photodetectors, etc.

[0003] In the manufacturing process of perovskite solar cells, solvents such as dimethyl sulfoxide are widely used to improve the film formation morphology of perovskite, but in the growth process of crystals, these solvents are easily trapped and cannot be dispersed, eventually leading to the appearance of voids and gaps at the interface between perovskite and substrate, the integrity of the morphology of perovskite thin film is destroyed, not only reducing the efficiency of the device, but also accelerating the film degradation process under light, greatly reducing the stability of the device. Therefore, researchers have adopted various ways to improve the film formation process and thin film properties of perovskite. CN105336856A discloses a method for preparing a perovskite thin film, which places the prepared perovskite precursor thin film in an organic amine gas for treatment, which can improve the film formation and reduce the roughness of the perovskite thin film. However, this method is relatively complex due to the use of organic amine gas, and has certain danger and pollution; CN111063804A discloses a preparation method of a perovskite light-absorbing layer thin film, which uses hydrohalic acid as an additive, dissolves the perovskite material and the hydrohalic acid with a solvent, heats and reacts the system for a period of time to form a perovskite precursor solution, and then obtains the perovskite light-absorbing layer thin film through spin coating and annealing. The addition of hydrohalic acid can reduce the annealing temperature, so that the solvent volatilization is slower, which is beneficial to the improvement of the film formation properties to some extent. However, the conversion efficiency of the solar cells prepared by the method is less than 10%.

[0004] Therefore, there is a need to develop a new method for preparing a perovskite thin film, which can manufacture a high-quality perovskite thin film with a simple process, reduce the generation of cavities, and thus improve the efficiency and stability of the perovskite thin film in a device. SUMMARY

[0005] In view of the problems in the prior art, the purpose of the present application is to provide a perovskite thin film and a preparation method and use thereof. The preparation method uses thiosemicarbazide as an additive of a perovskite precursor solution, and then performs spin coating and annealing on the perovskite precursor solution to obtain the perovskite thin film. By adding thiosemicarbazide, the polar and high-boiling properties of thiosemicarbazide are utilized to solve the problem of cavities in the perovskite thin film caused by solvent retention during the nucleation process of the perovskite thin film, and the contact condition of the bottom of the perovskite thin film and the conductive substrate is improved, thereby realizing the regulation of the crystallization process of the thin film. The preparation method can obtain a perovskite thin film with few cavities, high crystallinity, and uniformity. The fill factor of a solar cell based on the perovskite thin film can reach 0.73, and the photoelectric conversion efficiency can reach 15.6%.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a preparation method of a perovskite thin film, which comprises the following steps:

[0008] (1) preparing a perovskite precursor solution, which comprises a perovskite precursor material, thiosemicarbazide as an additive, and a solvent;

[0009] (2) spin coating the perovskite precursor solution of step (1) on a substrate to obtain a perovskite precursor dry film;

[0010] (3) performing annealing treatment on the perovskite precursor dry film of step (2) to obtain the perovskite thin film.

[0011] By adding the additive thiosemicarbazide to the perovskite precursor solution, the polar and high-boiling properties of thiosemicarbazide are utilized to inhibit the problem of cavities formed between the substrate and the bottom of the perovskite caused by solvent retention during the nucleation process of the perovskite, and the contact condition of the bottom of the perovskite thin film and the conductive substrate is improved, thereby realizing the regulation of the crystallization process of the thin film. The preparation method can obtain a perovskite thin film with few cavities, high crystallinity, and uniformity. When the high-quality perovskite thin film obtained by the preparation method of the present application is used in a perovskite solar cell, the fill factor of the device can reach 0.73, and the photoelectric conversion efficiency can reach 15.6%.

[0012] The following is a preferred technical solution of the present application, but is not a limitation of the technical solutions provided by the present application. Through the following technical solution, the technical purpose and beneficial effects of the present application can be better achieved and realized.

[0013] As a preferred technical solution of the present application, the perovskite precursor material in step (1) comprises AX and BX2, wherein A comprises C n H (2n+1) NH3 + , NH2CH=NH 2+ or Cs + , and n is an integer from 1 to 5; B comprises any one or a combination of at least two of Pb 2+ , Sn 2+ or Ge 2+ ; and X comprises any one or a combination of at least two of Cl - , Br - or I - .

[0014] It should be noted that the present application uses perovskite precursor materials AX and BX2, and produces perovskite thin films through the reaction between the two. However, at present, perovskite materials with complete composition and structure have been commercialized, and perovskite powders can be directly purchased and dissolved for use. Therefore, the additive thiocarbodiazine of the present application is still applicable to perovskite thin films obtained in this way and can still function normally. Those skilled in the art can select according to actual conditions.

[0015] Preferably, the concentration of the perovskite precursor material BX2 in the perovskite precursor solution in step (1) is 0.5-1.5 mmol / mL, such as 0.5 mmol / mL, 0.6 mmol / mL, 0.7 mmol / mL, 0.8 mmol / mL, 0.9 mmol / mL, 1.0 mmol / mL, 1.1 mmol / mL, 1.2 mmol / mL, 1.3 mmol / mL, 1.4 mmol / mL or 1.5 mmol / mL, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0016] Preferably, the molar ratio of the perovskite precursor materials AX and BX2 in the perovskite precursor solution in step (1) is (1-1.3):1, such as 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1 or 1.3:1, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0017] Preferably, the concentration of thiosemicarbazide in the perovskite precursor solution of step (1) is 0.5-3 mg / mL, such as 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL or 3 mg / mL, but not limited to the listed values, other values not listed in the above range are also applicable.

[0018] The present application can inhibit the formation of holes at the bottom of the perovskite film by adjusting the amount of additive thiosemicarbazide, thereby avoiding affecting the photoelectric properties of the perovskite film. When the amount of thiosemicarbazide is too small, the voids at the bottom of the film cannot be completely filled during the formation of the perovskite film, and the contact between the bottom of the perovskite film and the conductive substrate cannot be optimized. When the amount is too large, it will affect the normal crystallization of the perovskite film, and ultimately make the properties of the perovskite film worse.

[0019] Preferably, the solvent of step (1) includes any one or a combination of at least two of γ-butyrolactone, dimethyl sulfoxide, N,N-dimethylformamide, N-methyl pyrrolidone, ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, petroleum ether or chloroform. Typical but non-limiting examples of the combination include a combination of γ-butyrolactone and dimethyl sulfoxide, a combination of γ-butyrolactone and N,N-dimethylformamide, a combination of γ-butyrolactone and N-methyl pyrrolidone, a combination of dimethyl sulfoxide and N,N-dimethylformamide, a combination of dimethyl sulfoxide and N-methyl pyrrolidone, or a combination of N,N-dimethylformamide and N-methyl pyrrolidone, etc. Due to the length of the article and for the sake of simplicity, the present application will not exhaustively list all examples of the combination.

[0020] Preferably, the substrate is preheated before the spin coating of step (2).

[0021] Preferably, the preheating temperature of the preheating is 60-80°C, such as 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but not limited to the listed values, other values not listed in the above range are also applicable.

[0022] Preferably, the spin coating speed of step (2) is 3000-6000 rpm, such as 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, 5000 rpm, 5500 rpm or 6000 rpm, but not limited to the listed values, other values not listed in the above range are also applicable.

[0023] Preferably, the spin-coating time of the spin-coating in step (2) is 15-90 s, for example 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, 65 s, 70 s, 75 s, 80 s, 85 s or 90 s, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0024] Preferably, the annealing temperature of the annealing treatment in step (3) is 80-150℃, for example 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0025] Preferably, the annealing time of the annealing treatment in step (3) is 5-15 min, for example 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0026] Preferably, the preparation method comprises the following steps:

[0027] (1) dissolving the perovskite precursor material and the additive thiocarbodiazine in a solvent to form a perovskite precursor solution, the concentration of the perovskite precursor material BX2 in the perovskite precursor solution is 0.5-1.5 mmol / mL; the molar ratio of the perovskite precursor material AX to BX2 is (1-1.3):1; the concentration of the additive thiocarbodiazine is 0.5-3 mg / mL; the solvent comprises any one or a combination of at least two of γ-butyrolactone, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, petroleum ether or chloroform;

[0028] (2) dropwise adding the perovskite precursor solution in step (1) to a substrate preheated to 65-75℃ to form a perovskite precursor solution film, setting the rotation speed of a film applicator to 3000-6000 rpm and performing spin-coating for 30-90 s to obtain a perovskite precursor dry film;

[0029] (3) annealing the perovskite precursor dry film in step (2) at 80-150℃ for 5-15 min to obtain the perovskite thin film.

[0030] In a second aspect, the present application provides a perovskite thin film obtained by the preparation method according to the first aspect.

[0031] In a third aspect, the present application provides a perovskite solar cell, which comprises a substrate, and further comprises, from bottom to top, a hole transport layer, an active layer comprising the perovskite film according to the second aspect of the present application, an electron transport layer, and a metal electrode layer on one side of the substrate.

[0032] In a fourth aspect, the present application provides a photoelectric device, which comprises the perovskite film according to the second aspect of the present application.

[0033] Compared with the prior art, the present application has at least the following beneficial effects:

[0034] (1) The present application uses thiocarbodiazine as an additive of perovskite precursor solution, and makes it replace part of the solvent due to its polarity and high boiling point, so as to effectively solve the problem of perovskite film cavity caused by solvent retention during nucleation process, improve the contact condition of the bottom of perovskite film and the conductive substrate, realize the regulation of the film crystallization process, and finally not only reduce the number of holes on the bottom surface of perovskite film, but also improve the crystallinity of perovskite film and make the crystallization more uniform and complete.

[0035] (2) The fill factor and photoelectric conversion efficiency of the perovskite solar cell based on the perovskite film can reach 0.73 and 15.6%, respectively, and the perovskite film can also be applied to other photoelectric devices other than solar cells, such as perovskite light-emitting diodes, perovskite photodetectors, etc., and the preparation method can support large-scale production of perovskite film and photoelectric devices thereof. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 FIG. 1 is a scanning electron microscope image of the bottom of the perovskite film obtained in Example 1 of the present application;

[0037] Figure 2 FIG. 2 is a scanning electron microscope image of the bottom of the perovskite film obtained in Comparative Example 1 of the present application;

[0038] Figure 3 FIG. 3 is a device structure schematic diagram of the perovskite solar cell obtained in the examples and comparative examples of the present application, wherein 1 is a substrate, 2 is a hole transport layer, 3 is an active layer comprising a perovskite film, 4 is an electron transport layer, and 5 is a metal electrode layer. DETAILED DESCRIPTION

[0039] The technical solutions of the present application will be further described below in conjunction with the drawings and through specific embodiments. Those skilled in the art should understand that the examples are only to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0040] Example 1

[0041] The embodiment provides a preparation method of a perovskite film, and the preparation method comprises the following steps:

[0042] (1) 86 mg of C5H10NH3I, 111 mg of CH3NH3I, 415 mg of PbI2 and 1 mg of thiocarbodiazine are dissolved in a mixed solvent formed by 970 μL of N,N-dimethylformamide and 30 mL of dimethyl sulfoxide to form a perovskite precursor solution, wherein the concentration of PbI2 in the perovskite precursor solution is 0.9 mmol / mL; the molar ratio of the sum of C5H10NH3I and CH3NH3I to PbI2 is 1.22:1; and the concentration of thiocarbodiazine is 1 mg / mL; 11 NH3I), 51 mg of CH3NH3I, 231 mg of PbI2 and 0.5 mg of thiocarbodiazine are dissolved in a mixed solvent formed by 970 μL of N,N-dimethylformamide and 30 mL of dimethyl sulfoxide to form a perovskite precursor solution, wherein the concentration of PbI2 in the perovskite precursor solution is 0.5 mmol / mL; the molar ratio of the sum of C4H9NH3I and CH3NH3I to PbI2 is 1:1; and the concentration of thiocarbodiazine is 0.5 mg / mL;

[0043] (2) The perovskite precursor solution in step (1) is dropped onto a substrate preheated at 70 DEG C to form a perovskite precursor liquid film, a spin coater is set at a rotating speed of 4800 rpm and spin coating is performed for 60 s to obtain a perovskite precursor dry film.

[0044] (3) The perovskite precursor dry film in step (2) is subjected to annealing treatment at 100 DEG C for 10 min to obtain the perovskite film.

[0045] Embodiment 2

[0046] The embodiment provides a preparation method of a perovskite film, and the preparation method comprises the following steps:

[0047] (1) 86 mg of C5H10NH3I, 111 mg of CH3NH3I, 415 mg of PbI2 and 1 mg of thiocarbodiazine are dissolved in a mixed solvent formed by 970 μL of N,N-dimethylformamide and 30 mL of dimethyl sulfoxide to form a perovskite precursor solution, wherein the concentration of PbI2 in the perovskite precursor solution is 0.9 mmol / mL; the molar ratio of the sum of C5H10NH3I and CH3NH3I to PbI2 is 1.22:1; and the concentration of thiocarbodiazine is 1 mg / mL;

[0048] (2) The perovskite precursor solution in step (1) is dropped onto a substrate preheated at 65 DEG C to form a perovskite precursor liquid film, a spin coater is set at a rotating speed of 3000 rpm and spin coating is performed for 90 s to obtain a perovskite precursor dry film.

[0049] (3) The perovskite precursor dry film in step (2) is subjected to annealing treatment at 80 DEG C for 15 min to obtain the perovskite film.

[0050] Embodiment 3

[0051] The embodiment provides a preparation method of a perovskite film, and the preparation method comprises the following steps:

[0052] (1) 123 mg of C2H5NH3I, 197 mg of methylammonium iodide, 692 mg of lead iodide, and 3 mg of thiocarbodithioic acid hydrazide were dissolved in a mixed solvent of 970 μL of N,N-dimethylformamide and 30 mL of dimethyl sulfoxide to form a perovskite precursor solution, wherein the concentration of lead iodide in the perovskite precursor solution was 1.5 mmol / mL; the molar ratio of the sum of pentylammonium iodide and methylammonium iodide to lead iodide was 1.3:1; and the concentration of thiocarbodithioic acid hydrazide was 3 mg / mL;

[0053] (2) The perovskite precursor solution of step (1) was dropped onto a substrate preheated at 75°C to form a perovskite precursor solution film, and a spin coater was set to rotate at 6000 rpm for 30 s to obtain a perovskite precursor dry film.

[0054] (3) The perovskite precursor dry film of step (2) was annealed at 150°C for 5 min to obtain the perovskite thin film.

[0055] Example 4

[0056] The present example provides a method for preparing a perovskite thin film, which is identical to Example 1 except that 1 mg of thiocarbodithioic acid hydrazide in step (1) is adjusted to 0.1 mg of thiocarbodithioic acid hydrazide, so that the concentration of the adjusted thiocarbodithioic acid hydrazide changes from 1 mg / mL to 0.1 mg / mL.

[0057] Example 5

[0058] The present example provides a method for preparing a perovskite thin film, which is identical to Example 1 except that 1 mg of thiocarbodithioic acid hydrazide in step (1) is adjusted to 0.5 mg of thiocarbodithioic acid hydrazide, so that the concentration of the adjusted thiocarbodithioic acid hydrazide changes from 1 mg / mL to 0.5 mg / mL.

[0059] Example 6

[0060] The present example provides a method for preparing a perovskite thin film, which is identical to Example 1 except that 1 mg of thiocarbodithioic acid hydrazide in step (1) is adjusted to 2 mg of thiocarbodithioic acid hydrazide, so that the concentration of the adjusted thiocarbodithioic acid hydrazide changes from 1 mg / mL to 2 mg / mL.

[0061] Example 7

[0062] The present example provides a method for preparing a perovskite thin film, which is identical to Example 1 except that 1 mg of thiocarbodithioic acid hydrazide in step (1) is adjusted to 3 mg of thiocarbodithioic acid hydrazide, so that the concentration of the adjusted thiocarbodithioic acid hydrazide changes from 1 mg / mL to 3 mg / mL.

[0063] Example 8

[0064] This example provides a preparation method of perovskite thin film, which is identical to Example 1 except that 1 mg of thiosemicarbazide in step (1) is adjusted to 5 mg of thiosemicarbazide, so that the concentration of the adjusted thiosemicarbazide changes from 1 mg / mL to 5 mg / mL.

[0065] Comparative Example 1

[0066] This comparative example provides a preparation method of perovskite thin film, which does not contain thiosemicarbazide in the perovskite precursor solution in step (1), i.e. step (1) is: using a mixed solvent formed by 970 μL of N,N-dimethylformamide and 30 mL of dimethyl sulfoxide to dissolve 86 mg of pentylamine iodine (i.e. C5H 11 NH3I), 111 mg of methylamine iodine, 415 mg of lead iodide, to form a perovskite precursor solution, the concentration of lead iodide in the perovskite precursor solution is 0.9 mmol / mL; the molar ratio of the sum of pentylamine iodine and methylamine iodine to lead iodide is 1.22:1; except for step (1), the other steps and conditions of this comparative example are identical to Example 1.

[0067] The preparation method of perovskite thin film described in the examples and comparative examples is used to prepare perovskite solar cells from the obtained perovskite thin film, and the preparation steps are as follows:

[0068] S1. Cut ITO conductive glass into 10 cm x 10 cm size, ultrasonically clean in glass cleaner, deionized water and ethanol for 10 min respectively, blow dry the surface residual solvent, and then put it into the ultraviolet ozone machine for cleaning for 15 min to obtain a conductive substrate;

[0069] S2. Weigh 1.5 mg of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] dissolved in 1 mL of toluene solution to prepare a hole transport layer solution precursor; take a small amount of the hole transport layer precursor and drop it onto the conductive substrate of step S1, spin-coat it with a spin coater at a speed of 5000 rpm, and finally anneal it on a hot stage at 100°C for 10 min to form a hole transport layer, obtaining a composite A;

[0070] S3. Use the preparation method of perovskite thin film described in the examples and comparative examples to prepare the perovskite thin film on the side of the hole transport layer of the composite A obtained in step S2 to form an active layer, obtaining a composite B;

[0071] S4. An active layer side of the complex B described in step S3 is prepared by a thermal evaporation method to form an electron transport layer of 30 nm thick C60, then 6 nm thick BCP, and finally a metal electrode layer of 80 nm thick silver electrode, to form a metal electrode layer, to obtain the perovskite solar cell.

[0072] Figure 3 is a device structure schematic diagram of the perovskite solar cell obtained in the embodiment and comparative example of the present application, the perovskite solar cell comprising a substrate 1, further comprising a hole transport layer 2, an active layer 3 composed of the perovskite thin film, an electron transport layer 4 and a metal electrode layer 5 arranged in sequence from bottom to top on one side of the substrate.

[0073] All the perovskite solar cells obtained in the embodiment and comparative example are tested, and the obtained results are shown in Table 1.

[0074] Table 1

[0075]

[0076] It can be seen from Table 1 that:

[0077] (1) The fill factor and photoelectric conversion efficiency of the perovskite solar cell prepared in Example 1 reached 0.73 and 15.6%, respectively, while the fill factor and photoelectric conversion efficiency of the perovskite solar cell prepared in Comparative Example 1 without using thiosemicarbazide as an additive were 0.70 and 14%, respectively, indicating that the presence of the additive thiosemicarbazide had a significant improvement effect on the device performance, because thiosemicarbazide effectively regulated the crystallization process of the perovskite thin film, solved the problem of easy voids in the thin film, made the perovskite thin film more complete and uniform, and thus optimized the performance of the device;

[0078] The above results can be verified by the morphology change of the perovskite thin film, Figure 1 is a scanning electron microscope image of the bottom of the perovskite thin film obtained in Example 1 of the present application, when thiosemicarbazide is present in the perovskite precursor solution, the formed perovskite thin film is uniform, continuous, dense, has few voids with small volume, has high crystallinity, and finally has high film quality; Figure 2 is a scanning electron microscope image of the bottom of the perovskite thin film obtained in Comparative Example 1 of the present application, when thiosemicarbazide is not present in the perovskite precursor solution, the formed perovskite thin film has voids, has poor crystallinity, and finally has poor film quality;

[0079] (2) Comparing Example 1 with Examples 4-8 and Comparative Example 1, it was found that the amount of thiocarbazine used in Example 4 was very small, resulting in a concentration of thiocarbazine in the perovskite precursor solution that was lower than the preferred range of 0.5-3 mg / mL. Due to the insufficient effect of thiocarbazine, the conversion efficiency of the obtained device was only 0.3% higher than that of Comparative Example 1. In Examples 5-7, the amount of thiocarbazine was increased in turn, resulting in a concentration of thiocarbazine in the perovskite precursor solution that was increased in turn within the preferred range. The appropriate amount of thiocarbazine effectively reduced the voids at the bottom of the perovskite film, which reduced the defects at the interface and thus effectively reduced the recombination of charge carriers, ultimately achieving a higher photoelectric conversion efficiency. However, Example 8 used an excessive amount of additive, resulting in a concentration of thiocarbazine in the perovskite precursor solution that was higher than the preferred range. This affected the crystallinity of the perovskite film, which damaged the short-circuit current, open-circuit voltage, and fill factor of the obtained perovskite solar cell. The photoelectric conversion efficiency of the obtained device was significantly lower than that of Example 1.

[0080] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0081] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0082] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0083] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a perovskite thin film, characterized in that, The preparation method includes the following steps: (1) Prepare a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor material, thiocarbazine as an additive, and a solvent. (2) Spin-coat the perovskite precursor liquid described in step (1) onto the substrate to obtain a perovskite precursor dry film. (3) Anneal the perovskite precursor dry film obtained in step (2) to obtain a perovskite thin film; The concentration of thiocarbazine in the perovskite precursor solution in step (1) is 0.5–3 mg / mL.

2. The preparation method according to claim 1, characterized in that, The perovskite precursor material in step (1) includes AX and BX2, wherein A includes C n H (2n+1) NH3 + NH2CH=NH 2+ or Cs + Any combination of one or at least two of the following, where n is an integer from 1 to 5; B includes Pb 2+ Sn 2+ Or Ge 2+ Any one or at least two of the following; X includes Cl - ,Br - Or I - Any one or at least two of them.

3. The preparation method according to claim 1, characterized in that, The concentration of perovskite precursor material BX2 in the perovskite precursor solution in step (1) is 0.5 to 1.5 mmol / mL.

4. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of perovskite precursor material AX to BX2 in the perovskite precursor solution is (1-1.3):

1.

5. The preparation method according to claim 1, characterized in that, The solvent in step (1) includes any one or a combination of at least two of the following: γ-butyrolactone, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, petroleum ether, or chloroform.

6. The preparation method according to claim 1, characterized in that, Before spin coating in step (2), the substrate is preheated.

7. The preparation method according to claim 6, characterized in that, The preheating temperature is 60–80°C.

8. The preparation method according to claim 1, characterized in that, The spin coating speed in step (2) is 3000-6000 rpm.

9. The preparation method according to claim 1, characterized in that, The spin coating time in step (2) is 15 to 90 seconds.

10. The preparation method according to claim 1, characterized in that, The annealing temperature for the annealing process in step (3) is 80 to 150°C.

11. The preparation method according to claim 1, characterized in that, The annealing time for the annealing process in step (3) is 5 to 15 minutes.

12. The preparation method according to any one of claims 1-11, characterized in that, The preparation method includes the following steps: (1) A perovskite precursor material and thiocarbazine as an additive are dissolved in a solvent to form a perovskite precursor solution, wherein the concentration of the perovskite precursor material BX2 in the perovskite precursor solution is 0.5-1.5 mmol / mL; the molar ratio of the perovskite precursor material AX to BX2 is (1-1.3):1; the concentration of the additive thiocarbazine is 0.5-3 mg / mL; the solvent includes any one or a combination of at least two of γ-butyrolactone, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, petroleum ether or chloroform. (2) The perovskite precursor liquid described in step (1) is dropped onto a substrate preheated at 65-75°C to form a perovskite precursor liquid film. The spin coater is set to a speed of 3000-6000 rpm and spin-coated for 30-90 seconds to obtain a perovskite precursor dry film. (3) The perovskite precursor dry film obtained in step (2) is annealed at 80-150°C for 5-15 minutes to obtain the perovskite film.

13. A perovskite thin film obtained by the preparation method according to any one of claims 1-12.

14. A perovskite solar cell, characterized in that, The perovskite solar cell includes a substrate, and further includes a hole transport layer, an active layer composed of a perovskite thin film as described in claim 13, an electron transport layer, and a metal electrode layer disposed sequentially from bottom to top on one side of the substrate.

15. An optoelectronic device, characterized in that, The optoelectronic device contains the perovskite thin film as described in claim 13.

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