Large-area perovskite layer and method for producing same

Abstract

The application provides a large-area perovskite layer and a preparation method thereof, and the preparation method comprises the following steps: dissolving raw materials for forming the perovskite in an ionic liquid or a mixture of the ionic liquid and an organic solvent to form a perovskite precursor, and coating the perovskite precursor on the surface of a crystalline silicon bottom cell to obtain the perovskite layer. According to the application, the raw materials for forming the perovskite are dissolved in the ionic liquid or the mixture of the ionic liquid and the organic solvent to form the perovskite precursor, so that the influence of water and oxygen in the air on the perovskite precursor is reduced, and the preparation of the perovskite layer can be carried out in an air atmosphere. Furthermore, in combination with the coating mode, the large-area perovskite layer can be prepared, and the application is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cells, and particularly relates to a large-area perovskite layer and a preparation method thereof. BACKGROUND

[0002] The energy conversion efficiency of a solar cell device is one of the key performances of the device. At present, the crystalline silicon solar cell, which occupies the absolute main body of the photovoltaic market, has a material absorption band gap of 1.12 eV, and cannot reasonably utilize the short-wavelength light in the solar spectrum. In recent years, the perovskite material, which has obtained continuous attention in the photovoltaic field, can realize controllable adjustment of the band gap in the range of 1.5 to 2.3 eV by changing the components of the perovskite material. Meanwhile, the perovskite material is low in cost and simple to prepare. If a wide-bandgap perovskite top cell is deposited on a crystalline silicon cell to form a tandem solar cell, the spectral response can be widened to the greatest extent under the premise of slight increase in cost, and the efficiency of the device can be greatly improved. The theoretical efficiency of the two-end tandem solar cell of the crystalline silicon bottom cell-perovskite top cell can reach 44%, which is a new type of photovoltaic cell technology that is expected to overturn the market.

[0003] However, the perovskite material is very sensitive to water and oxygen in the air and the like, and therefore, at present, the high-efficiency perovskite solar cell is mainly prepared in a glove box. In the current conventional technical scheme, the perovskite precursor solution preparation still needs to contact water and oxygen in the air. On the one hand, some solvents that are easily miscible with water are easy to absorb water, and it is not easy to remove the water after the solvents enter the precursor solution. On the other hand, the components in the precursor are easy to be oxidized, causing insufficient reaction of the components, forming defects, and affecting the performance of the device. In order for the perovskite tandem cell to be commercialized, the device needs to be prepared in the air and be able to adapt to changes in different humidity.

[0004] CN109065725A discloses a method for preparing a high-efficiency and stable perovskite solar cell by adding a surfactant to a perovskite layer. The perovskite solar cell is composed of a conductive glass substrate, an electron transport layer, a perovskite layer, a hole transport layer and a metal electrode stacked in sequence. The application adds a cationic surfactant to the perovskite precursor solution and controls the content of the cationic surfactant to prepare a perovskite layer, reduces the surface defects of the thin film, controls the film morphology and crystallinity of the perovskite active layer, and improves the photoelectric conversion efficiency and the stability of the perovskite solar cell, thereby providing a new preparation method for preparing a high-efficiency and stable perovskite solar cell. The application has the advantages of simple process, low cost, improved photoelectric performance and stability of the perovskite solar cell, and good commercial application prospect.

[0005] CN110718632A discloses a method for preparing a large-area perovskite layer and a perovskite solar cell, which comprises the following steps: coating a perovskite precursor solution on a substrate to form a perovskite precursor layer; adding a mixed anti-solvent, and annealing to obtain a perovskite layer; the mixed anti-solvent is a mixed solvent formed by mixing an A solvent and a B solvent, the A solvent is selected from any one of toluene, chlorobenzene, dichloromethane, ethyl acetate, anisole and diethyl ether, the B solvent is selected from any one of toluene, chlorobenzene, dichloromethane, ethyl acetate, anisole and a monohydric alcohol with 3-6 carbon atoms, the A solvent is different from the B solvent, and the volume ratio of the A solvent in the mixed anti-solvent is 10-90%. The application utilizes the mixed anti-solvent to reduce the supersaturation degree of the perovskite precursor solution in the crystallization process, so that the nucleation sites are uniformly generated, and finally a perovskite thin film with uniform film formation and large grain size is obtained, which has a good application prospect in the field of preparing large-area perovskite devices.

[0006] The existing perovskite layer has problems of high preparation process requirement, poor uniformity and inability to be prepared in a large area, and therefore how to ensure the uniformity of the perovskite layer while achieving the requirements of low preparation process requirement and large-area preparation has become an urgent problem to be solved. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a large-area perovskite layer and a preparation method thereof, which dissolves the raw materials of perovskite in an ionic liquid or a mixture of an ionic liquid and an organic solvent to form a perovskite precursor, reduces the influence of water and oxygen in the air on the perovskite precursor, and thus can prepare the perovskite layer in an air atmosphere, and further, in combination with a coating method, can prepare a large-area perovskite layer, which is suitable for industrial production.

[0008] To achieve the above purpose, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a preparation method of a large-area perovskite layer, which comprises the following steps:

[0010] The raw materials of perovskite are dissolved in an ionic liquid or a mixture of an ionic liquid and an organic solvent to form a perovskite precursor, and the perovskite precursor is coated on the surface of a crystalline silicon bottom cell to prepare a perovskite layer.

[0011] The present application dissolves the raw materials of perovskite in an ionic liquid or a mixture of an ionic liquid and an organic solvent, which reduces the influence of water and oxygen in the air on the preparation of the perovskite layer from the precursor, and further, in combination with a coating operation, realizes more efficient large-area preparation of the perovskite layer in the air, thereby improving the production efficiency of the perovskite-based battery, and the perovskite layer prepared by the present application has uniform morphology, and has the characteristics of simple preparation method, suitability for industrial production and low cost.

[0012] As a preferred technical solution of the present application, the raw material of the perovskite includes a metal halide and an additive.

[0013] Preferably, the molar ratio of the metal halide and the additive is (0.5-1.5):1, for example 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1.

[0014] Preferably, the metal halide includes one or a combination of at least two of SnI2, SnBr2, SnF2, SnCl2, PbI2, PbBr2 or PbCl2.

[0015] Preferably, the additive includes one or a combination of at least two of CH3NH3I, CH3NH3Cl, CH3NH3Br, CH2(NH2)2I, CH2(NH2)2Br, CH2(NH2)2Cl, CsI, RbI, KI, CsBr or CsCl.

[0016] As a preferred technical solution of the present application, the molar concentration of the raw material of the perovskite in the perovskite precursor is 0.1-5 mol / L, for example 0.1 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, 4.0 mol / L, 4.5 mol / L or 5.0 mol / L.

[0017] Preferably, the volume ratio of the organic solvent to the ionic liquid is (0-1000):1, for example 10:1, 50:1, 100:1, 200:1, 300:1, 400:1, 500:1, 600:1, 700:1, 800:1, 900:1 or 1000:1, further preferably (0-100):1.

[0018] As a preferred technical solution of the present application, the ionic liquid includes one or a combination of at least two of 1,1,1-trifluoroethylammonium iodide, methylformamide, methylammonium acetate, methylammonium difluoroacetate or 1-butyl-3-methylimidazolium tetrafluoroborate.

[0019] Preferably, the organic solvent includes one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, tetramethylene sulfoxide, sulfolane or N-methylpyrrolidone.

[0020] As a preferred technical solution of the present application, the coating step comprises: first coating the perovskite precursor on the surface of the substrate, and then performing spin coating treatment on the remaining solvent in the film.

[0021] Preferably, the substrate comprises one or a combination of at least two of an ITO-deposited glass substrate, an FTO-deposited glass substrate, a polyimide flexible substrate, an ethylene glycol naphthalene diacetate flexible substrate, or a crystalline silicon substrate.

[0022] Preferably, the crystalline silicon substrate comprises one or a combination of at least two of a single-crystal silicon wafer, a doped single-crystal silicon wafer, a polycrystalline silicon wafer, a doped polycrystalline silicon wafer, an amorphous silicon wafer, or a doped amorphous silicon wafer.

[0023] As a preferred technical solution of the present application, the coating speed is 0.01-1 m / s, for example, 0.01 m / s, 0.05 m / s, 0.1 m / s, 0.2 m / s, 0.3 m / s, 0.4 m / s, 0.5 m / s, 0.6 m / s, 0.7 m / s, 0.8 m / s, 0.9 m / s, or 1.0 m / s.

[0024] Preferably, the spin coating rotation speed is 100-6000 rpm, for example, 100 rpm, 600 rpm, 1200 rpm, 1800 rpm, 2400 rpm, 3000 rpm, 3600 rpm, 4200 rpm, 4800 rpm, 5400 rpm, or 6000 rpm.

[0025] Preferably, the spin coating time is 10-1000 s, for example, 10 s, 50 s, 100 s, 200 s, 300 s, 400 s, 500 s, 600 s, 700 s, 800 s, 900 s, or 1000 s.

[0026] Preferably, the spin coating process uses a spin coater.

[0027] Preferably, the preparation method is performed in an air atmosphere.

[0028] As a preferred technical solution of the present application, the coating is followed by a heating treatment.

[0029] Preferably, the heating treatment temperature is 70-150℃, for example, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, or 150℃.

[0030] Preferably, the heating treatment is performed for 1-120 min, such as 1 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, further preferably 10-60 min.

[0031] As a preferred technical solution of the present application, the preparation method specifically comprises the following steps:

[0032] (I) mixing the metal halide and the additive in a molar ratio of (0.5-1.5):1 under an air atmosphere, and dissolving in a mixture of the ionic liquid and the organic solvent, the volume ratio of the organic solvent to the ionic liquid being 0-1000:1, to form a perovskite precursor, the molar concentration of the perovskite raw material in the perovskite precursor being 0.1-5 mol / L;

[0033] (II) coating the perovskite precursor on the surface of the substrate at a speed of 0.01-1 m / s, and then spin-coating at 100-6000 rpm for 10-1000 s, and then heating at 70-150℃ for 1-120 min to prepare the perovskite layer.

[0034] In a second aspect, the present application provides a large-area perovskite layer, the morphology of which is uniform, and the large-area perovskite layer is prepared by the preparation method of the large-area perovskite layer according to the first aspect.

[0035] As a preferred technical solution of the present application, the band gap of the large-area perovskite layer is 1.3-1.8 eV, such as 1.30 eV, 1.35 eV, 1.40 eV, 1.45 eV, 1.50 eV, 1.53 eV, 1.56 eV, 1.59 eV, 1.62 eV, 1.65 eV, 1.68 eV, 1.71 eV, 1.74 eV, 1.77 eV or 1.80 eV.

[0036] Preferably, the area of the large-area perovskite layer is 5-1000 cm 2 , such as 5 cm 2 , 10 cm 2 , 50 cm 2 , 100 cm 2 , 200 cm 2 , 300 cm 2 , 400 cm 2 , 500 cm 2 , 600 cm 2 , 700 cm 2 , 800 cm 2 , 900 cm 2or 1000 cm 2 .

[0037] The numerical ranges recited herein include all values from and including the lower and upper values. This is true even if the values included in the lower or upper range are outside of the recited range. The ranges are presented essentially to reflect the broadest intended scope of the numerical ranges. Unless otherwise stated, the numerical values are not intended to be absolute.

[0038] Compared with the prior art, the present application has the beneficial effects that:

[0039] The present application reduces the influence of water oxygen in the air in the process of preparing the perovskite layer from the precursor by dissolving the perovskite raw material in the ionic liquid or the mixture of the ionic liquid and the organic solvent, further, in combination with the coating operation, the perovskite layer is more efficiently prepared in the air in a large area, thereby improving the production efficiency of the perovskite-based battery, and the perovskite layer prepared by the present application has uniform morphology, and has the characteristics of simple preparation method, suitable for industrial production and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A flowchart of the preparation method of the large-area perovskite layer provided in Embodiment 1-4 of the present application is shown in the figure;

[0041] Figure 2 An edge morphology diagram of the large-area perovskite layer provided in Embodiment 1 of the present application is shown in the figure;

[0042] Figure 3 A center morphology diagram of the large-area perovskite layer provided in Embodiment 1 of the present application is shown in the figure;

[0043] Figure 4 An edge cross-sectional morphology diagram of the large-area perovskite layer provided in Embodiment 1 of the present application is shown in the figure;

[0044] Figure 5 A center cross-sectional morphology diagram of the large-area perovskite layer provided in Embodiment 1 of the present application is shown in the figure. DETAILED DESCRIPTION

[0045] In order to better illustrate the present application and facilitate the understanding of the technical solutions of the present application, the present application will be further described in detail below. However, the following examples are only simple examples of the present application, and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0046] Embodiment 1

[0047] The present embodiment provides a preparation method of a large-area perovskite layer, as shown in the figure, which specifically comprises the following steps: Figure 1

[0048] ​(I) under air atmosphere, air humidity is 30%, PbI2 and additives are mixed according to a molar ratio of 1:1, the additives are a mixture of CH2(NH2)2Br, CsI and CH2(NH2)2I, FA represents CH2(NH2)2 + , to form a perovskite raw material of formula FA 0.8 Cs 0.2 Pb(I 0.75 Br 0.25 )3, and the perovskite raw material is dissolved in methylammonium difluoroacetate, N,N-dimethylformamide is further added to the methylammonium difluoroacetate, the volume ratio of the N,N-dimethylformamide to the methylammonium formate is 3:7, to form a perovskite precursor, the molar concentration of the perovskite raw material in the perovskite precursor is 1.4 mol / L;

[0049] (II) the perovskite precursor is coated on the edge of a 158*158 mm 2 silicon wafer at a speed of 0.05 m / s, and coats the entire surface, a spin coater is used for spin coating treatment at 4000 rpm for 20 s, and then heating is performed at 130°C for 20 min, to prepare a perovskite layer, the band gap of which is 1.7 eV.

[0050] Example 2

[0051] The embodiment provides a preparation method of a large-area perovskite layer, as shown in the following scheme, and specifically comprises the following steps: Figure 1

[0052] (I) under air atmosphere, air humidity is 50%, PbI2 and CH2(NH2)2I are mixed according to a molar ratio of 1:1, and are dissolved in methylammonium formate, N,N-dimethylformamide is further added to the methylammonium formate, the volume ratio of the N,N-dimethylformamide to the methylammonium formate is 2:8, to form a perovskite precursor, the molar concentration of the perovskite raw material in the perovskite precursor is 1.3 mol / L;

[0053] (II) the perovskite precursor is coated on the edge of a 210*210 mm 2 silicon wafer at a speed of 0.01 m / s, and coats the entire surface, a spin coater is used for spin coating treatment at 5000 rpm for 30 s, and then heating is performed at 100°C for 30 min, to prepare a perovskite layer, the band gap of which is 1.5 eV.

[0054] Example 3

[0055] The embodiment provides a preparation method of a large-area perovskite layer, as shown in the following scheme, and specifically comprises the following steps: Figure 1

[0056] ​​(I) Under an air atmosphere with an air humidity of 40%, PbI2 and CH3NH3Br are mixed in a molar ratio of 1.5:1 and dissolved in 1,1,1-trifluoroethylammonium iodide to form a perovskite precursor. The molar concentration of the perovskite raw material in the precursor solution is 1.4 mol / L.

[0057] (II) The perovskite precursor was coated onto a 158*158mm film at a speed of 0.1 m / s. 2 The edges of the silicon wafer were coated and the entire surface was coated. The coating was then spin-coated at 100 rpm for 120 seconds, followed by heating at 150°C for 10 minutes to prepare a perovskite layer with a band gap of 1.8 eV.

[0058] Example 4

[0059] This embodiment provides a method for preparing a large-area perovskite layer, such as... Figure 1 As shown, the specific steps include:

[0060] (I) Under an air atmosphere with an air humidity of 30%, PbCl2 and CsI are mixed in a molar ratio of 0.5:1 and dissolved in ammonium acetate to form a perovskite precursor. The molar concentration of the perovskite raw material in the perovskite precursor is 1.4 mol / L.

[0061] (II) The perovskite precursor was coated onto a 200*200cm plate at a speed of 1 m / s. 2 The edges of the silicon wafer were coated and the entire surface was coated. The coating was then spin-coated at 6000 rpm for 25 seconds and then heated at 70°C for 120 minutes to prepare a perovskite layer with a band gap of 1.6 eV.

[0062] The surface and cross-section of the large-area perovskite layer prepared in Example 1 were characterized by SEM. The edge morphology of the silicon wafer is shown in the figure below. Figure 2 As shown, the intermediate morphology diagram is as follows: Figure 3 As shown, the edge cross-sectional topography diagram is as follows: Figure 4 As shown, the central cross-sectional topography is as follows: Figure 5 As shown.

[0063] pass Figures 2-5 As can be seen, this invention reduces the influence of water and oxygen in the air by dissolving perovskite raw materials in ionic liquids during the preparation of the perovskite layer in the precursor solution. Furthermore, combined with the coating operation, it achieves more efficient large-area preparation of the perovskite layer in air, thereby improving the production efficiency of crystalline silicon / perovskite tandem solar cells. Moreover, the perovskite layer prepared by this invention has a uniform morphology and can be prepared on a large scale with an area of ​​5–1000 cm². 2 The perovskite layer has the advantages of simple preparation method, suitability for industrial production and low cost.

[0064] The applicant states that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and it should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought out by those skilled in the art, and all of them fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing a large-area perovskite layer, characterized in that The preparation method comprises the following steps: The raw materials of the perovskite are dissolved in a mixture of an ionic liquid and an organic solvent to form a perovskite precursor, and the perovskite precursor is coated on the surface of a crystalline silicon bottom cell to prepare a perovskite layer. The volume ratio of the organic solvent to the ionic liquid is (0.25-100):1; the ionic liquid is one or a combination of at least two of 1,1,1-trifluoroethyl ammonium iodide, methylamine formate, methylammonium difluoroacetate or 1-butyl-3-methyl imidazole tetrafluoroborate. The coating step comprises the following steps: firstly, the perovskite precursor is coated on the surface of the substrate, and then a spin coating process is performed to remove the residual solvent in the film. The coating speed is 0.01-1 m / s.

2. The production method according to claim 1, characterized by, The raw materials of the perovskite comprise metal halides and additives.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the metal halides to the additives is (0.5-1.5):

1.

4. The production method according to claim 3, characterized by, The molar ratio of the metal halides to the additives is (0.9-1.1):

1.

5. The preparation method according to claim 2, characterized in that, The metal halides comprise one or a combination of at least two of SnI2, SnBr2, SnF2, SnCl2, PbI2, PbBr2 or PbCl2.

6. The preparation method according to claim 2, characterized in that, The additives comprise one or a combination of at least two of CH3NH3I, CH3NH3Cl, CH3NH3Br, CH2(NH2)2I, CH2(NH2)2Br, CH2(NH2)2Cl, CsI, RbI, KI, CsBr or CsCl.

7. The preparation method according to claim 1, characterized in that, The molar concentration of the raw materials of the perovskite in the perovskite precursor is 0.1-5 mol / L.

8. The method of claim 1, wherein, The organic solvent comprises one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, tetramethylene sulfoxide, sulfolane or N-methyl pyrrolidone.

9. The method of claim 1, wherein, The substrate comprises one or a combination of at least two of a glass substrate on which ITO is deposited, a glass substrate on which FTO is deposited, a polyimide flexible substrate, a naphthalene diacetate ethylene glycol flexible substrate or a crystalline silicon substrate.

10. The method of claim 1, wherein, The crystalline silicon substrate comprises one or a combination of at least two of a single crystal silicon wafer, a doped single crystal silicon wafer, a polycrystalline silicon wafer, a doped polycrystalline silicon wafer, an amorphous silicon wafer or a doped amorphous silicon wafer.

11. The method of claim 1, wherein, The rotation speed of the spin coating is 100-6000 rpm.

12. The method of claim 1, wherein, The spin coating time is 10-1000 s.

13. The method of claim 1, wherein, The spin coating process adopts a spin coater.

14. The method of claim 1, wherein, The preparation method is performed in an air atmosphere.

15. The method of claim 1, wherein, The coating is followed by a heating treatment.

16. The method of claim 15, wherein, The heating treatment temperature is 70-150 ℃.

17. The preparation method according to claim 15, characterized in that, The heating treatment time is 1-120 min.

18. The method of claim 17, wherein, The heating treatment time is 10-60 min.

19. The method of claim 1, wherein, The preparation method specifically comprises the following steps: (Ⅰ) under an air atmosphere, metal halides and additives are mixed in a molar ratio of (0.5-1.5):1, and are dissolved in a mixture of an ionic liquid and an organic solvent, the volume ratio of the organic solvent to the ionic liquid is 0.25-100:1, the molar concentration of the raw materials of the perovskite in the perovskite precursor is 0.1-5 mol / L; The ionic liquid is one or a combination of at least two of 1,1,1-trifluoroethylammonium iodide, methylamine formate, methylammonium difluoroacetate or 1-butyl-3-methylimidazolium tetrafluoroborate; (II) the perovskite precursor is coated on the surface of the substrate at a speed of 0.01-1 m / s, and then spin-coated at 100-6000 rpm for 10-1000 s, and heated at 70-150 ℃ for 1-120 min to obtain the perovskite layer.

20. A large area perovskite layer, characterized in that, The morphology of the large-area perovskite layer is uniform, and the large-area perovskite layer is prepared by the preparation method of the large-area perovskite layer in any one of claims 1-19.

21. The large area perovskite layer according to claim 20, wherein The band gap of the large-area perovskite layer is 1.3-1.8 eV.

22. The large area perovskite layer of claim 20, wherein, The area of the large-area perovskite layer is 5-1000 cm 2 .

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