Perovskite solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to the field of solar cells, and discloses a perovskite solar cell, a preparation method thereof and a photovoltaic module. The preparation method comprises the steps that a lead halide framework layer containing an additive is manufactured on a substrate, the additive is Lewis base, and the mass concentration of the additive in the lead halide framework layer ranges from 0.4 mg / mL to 0.7 mg / mL; coating the lead halide framework layer with a cation solution, and annealing to obtain a perovskite layer; and performing post-treatment to obtain the perovskite solar cell. By adopting the preparation method, the crystal quality of the lead halide framework layer can be effectively improved, so that the crystal quality of the perovskite layer can be improved.

Description

Technical Field

[0001] The present application relates to the field of solar cell technology, and in particular to a perovskite solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0002] As the core structure of perovskite solar cells, the crystal quality of the perovskite layer is an important factor affecting the performance of perovskite solar cells.

[0003] However, when using the two-step method to prepare the perovskite layer, the crystal quality of the perovskite layer is affected not only by the cationic solution but also by the quality of the lead halide skeleton layer. Therefore, how to improve the quality of the lead halide skeleton layer and improve the crystal quality of the perovskite layer has become an urgent problem that needs to be solved. Summary of the Invention

[0004] The present invention discloses a perovskite solar cell and a preparation method thereof, as well as a photovoltaic module. The preparation method can effectively improve the crystal quality of the lead halide skeleton layer, thereby helping to improve the crystal quality of the perovskite layer.

[0005] In a first aspect, an embodiment of the present application provides a method for preparing a perovskite solar cell, the method comprising:

[0006] Producing a lead halide skeleton layer containing an additive on a substrate, wherein the additive is a Lewis base and the mass concentration of the additive in the lead halide skeleton layer is 0.4 mg / mL to 0.7 mg / mL;

[0007] coating a cationic solution on the lead halide skeleton layer and annealing to obtain a perovskite layer;

[0008] After post-processing, the perovskite solar cell is obtained.

[0009] Furthermore, the groups of the additive include carbonyl and amino groups.

[0010] Furthermore, the step of preparing a lead halide skeleton layer containing additives on a substrate comprises:

[0011] preparing a skeleton layer precursor on the substrate;

[0012] The additive is coated on the skeleton layer precursor and annealed to obtain the lead halide skeleton layer.

[0013] Furthermore, the thickness of the skeleton layer precursor is 350nm to 470nm.

[0014] Furthermore, in the step of preparing the lead halide skeleton layer containing additives on the substrate, the annealing temperature is 100° C. to 150° C., and the annealing time is 10 min to 20 min.

[0015] Furthermore, in the step of coating the additive on the skeleton layer precursor, the spin coating time is 20s to 35s; and the spin coating speed is 3000rpm to 5000rpm.

[0016] Furthermore, the additive includes at least one of acetamide and propionamide; and / or,

[0017] The cationic solution comprises at least one of formamidine iodide, methylammonium bromide, and methylammonium chloride, wherein the concentration of the formamidine iodide in the cationic solution is 30 mg / mL to 50 mg / mL, the concentration of the methylammonium bromide in the cationic solution is 3 mg / mL to 6 mg / mL, and the concentration of the methylammonium chloride in the cationic solution is 7 mg / mL to 14 mg / mL; and / or,

[0018] A pyramid structure is provided on the substrate; and / or,

[0019] The cationic solution is coated on the lead halide skeleton layer, and the annealing temperature is 130° C. to 140° C., and the annealing time is 25 min to 35 min;

[0020] The thickness of the perovskite layer is 455nm-650nm.

[0021] In a second aspect, an embodiment of the present application discloses a perovskite solar cell, which is prepared by the preparation method as described in any one of the first aspects.

[0022] Furthermore, the perovskite raw material used to prepare the perovskite layer includes lead halide, and in the perovskite layer, the ratio of the peak intensity of the characteristic diffraction peak of the lead halide to the characteristic diffraction peak of the 001 crystal plane of the perovskite crystal is 0.076 to 0.23.

[0023] Furthermore, the perovskite solar cell is a stacked cell, the substrate includes a bottom cell, an electron-hole combination layer provided on the bottom cell, and a first transport layer, the perovskite layer is provided on the side of the first transport layer away from the electron-hole combination layer, the perovskite solar cell further includes a second transport layer and a transparent conductive layer sequentially provided on the side of the perovskite layer away from the first transport layer, the perovskite solar cell further includes a first electrode and a second electrode, the first electrode is in ohmic contact with the transparent conductive layer, and the second electrode is in ohmic contact with the bottom cell, wherein one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode;

[0024] Alternatively, the perovskite solar cell is a single-junction cell, the substrate includes a transparent conductive substrate and a first transport layer provided on the transparent conductive substrate, the perovskite layer is provided on the side of the first transport layer facing away from the transparent conductive substrate, the solar cell also includes a second transport layer provided on the side of the perovskite layer facing away from the first transport layer, the perovskite solar cell also includes a first electrode and a second electrode, the first electrode is in ohmic contact with the second transport layer, and the second electrode is in ohmic contact with the transparent conductive substrate, wherein one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, and one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode.

[0025] In a third aspect, an embodiment of the present application discloses a photovoltaic module, comprising: a perovskite solar cell as described in any one of the second aspects.

[0026] Compared with the prior art, the beneficial effect of the present application is that: the present application provides a perovskite solar cell and its preparation method, and a photovoltaic module. The preparation method can effectively improve the crystal quality of the lead halide skeleton layer, thereby helping to improve the crystal quality of the perovskite layer.

[0027] Specifically, the lead halide skeleton layer of the present application contains an additive, and the additive is a Lewis base. By controlling the mass concentration of the additive to be 0.4 mg / mL to 0.7 mg / mL, the additive with Lewis base properties can be combined with the lead halide material to a high degree, thereby reacting to form an intermediate complex of lead halide-additive. The intermediate complex can reduce the crystallization growth rate of the lead halide and inhibit nucleation, thereby ensuring that the prepared lead halide has a larger grain size, fewer grain boundaries and defects, and thus the number of nucleation sites of the perovskite phase on the lead halide is smaller, thereby helping to promote the acquisition of perovskite crystals with larger grain sizes. In addition, since the number of nucleation sites of lead halide crystals is small, when the cationic solution is coated on the lead halide skeleton layer, the amount of cationic solution that can participate in its single nucleation site will increase, thereby helping to promote the growth of perovskite crystals and produce perovskite crystals with larger grain sizes; and the cationic solution will then work together with the lead halide and additives to form an intermediate phase of the perovskite material. The presence of the intermediate phase helps to slow down the crystallization rate of the perovskite crystals, thereby promoting the sufficiency of the reaction between the cationic solution and the lead halide, thereby helping to reduce the defects of the perovskite crystals and generate perovskite crystals with higher quality.

[0028] Moreover, by introducing additives into the lead halide skeleton layer and controlling the mass concentration of the additives within the above-mentioned range, it is also helpful to adjust the porosity of the lead halide skeleton layer so that the lead halide skeleton layer has an appropriate porosity, which helps to promote the diffusion of the cationic solution into the interior of the skeleton layer and reduce the problem of lead halide residue. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 This is a process flow chart for preparing a perovskite solar cell provided in an embodiment of the present application;

[0031] Figure 2 This is a process flow chart for preparing a lead halide skeleton layer provided in an embodiment of the present application;

[0032] Figure 3 1 is a schematic structural diagram of a laminated battery provided in an embodiment of the present application;

[0033] Figure 4 Schematic diagram of another structure of a laminated battery provided in an embodiment of the present application;

[0034] Figure 5 It is a schematic structural diagram of a single-junction battery provided in an embodiment of the present application.

[0035] Icons: 1. Substrate; 11. Bottom battery; 12. Electron-hole recombination layer; 13. First transport layer; 14. Transparent conductive substrate; 2. Perovskite layer; 3. Second transport layer; 4. Transparent conductive layer; 5. First electrode; 6. Second electrode; 7. Passivation layer; 8. Buffer layer; 9. Anti-reflection layer. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0038] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0039] Furthermore, the terms "first," "second," etc., are primarily used to distinguish between different devices, elements, or components (which may or may not be of the same type and configuration), and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0040] The technical solution provided by the present invention will be further described below with reference to the embodiments and drawings.

[0041] The perovskite layer is the core structure of perovskite solar cells, responsible for absorbing light and generating photogenerated electrons and photogenerated holes. The crystal quality of the perovskite layer is a key factor affecting the performance of the perovskite layer. Its parameters such as crystal size and defect density directly affect the separation and transmission efficiency of photogenerated electron-hole pairs.

[0042] The two-step process for preparing the perovskite layer involves a synergistic reaction between inorganic and organic components. During this process, the organic components penetrate the inorganic framework and undergo a self-assembly reaction, transforming the initial framework into a perovskite phase. During this reaction, the lead halide framework layer serves as a substrate, and its quality affects the formation of the perovskite crystal.

[0043] Among them, the lead halide skeleton layer has smaller grains and more defects, and its surface will expose more nucleation sites. These abundant nucleation sites will enhance the activity of the reaction interface and increase the reaction rate of the lead halide skeleton layer with the cationic solution, resulting in an increase in the consumption rate of the cationic solution, forming a smaller and more defect-intensive crystal structure, which in turn seriously restricts the improvement of the photoelectric conversion efficiency of perovskite solar cells.

[0044] Based on the above problems, the embodiments of the present application provide a perovskite solar cell and a preparation method thereof, and a photovoltaic module. The preparation method can effectively improve the crystal quality of the lead halide skeleton layer, thereby improving the crystal quality of the perovskite layer.

[0045] The first aspect, such as Figure 1 As shown, the embodiment of the present application discloses a method for preparing a perovskite solar cell, the preparation method comprising:

[0046] A lead halide skeleton layer containing an additive is prepared on a substrate, wherein the additive is a Lewis base and the mass concentration of the additive in the lead halide skeleton layer is 0.4 mg / mL to 0.7 mg / mL;

[0047] coating a cationic solution on the lead halide skeleton layer and annealing to obtain a perovskite layer;

[0048] After post-processing, perovskite solar cells are obtained.

[0049] The lead halide skeleton layer of the present application contains an additive, and the additive is a Lewis base. Therefore, the mass concentration of the additive is controlled to be 0.4 mg / mL to 0.7 mg / mL, so that the additive with Lewis base properties can be combined with the lead halide material to a high degree, thereby reacting to form an intermediate complex of lead halide-additive. The intermediate complex can reduce the crystallization growth rate of the lead halide and inhibit the nucleation of the lead halide, thereby ensuring that the prepared lead halide has a larger grain size, fewer grain boundaries and defects.

[0050] Therefore, when the lead halide grain size is larger and the grain boundaries and defects are fewer, it helps to reduce the nucleation sites of the perovskite material on the lead halide, thereby helping to increase the content of the cationic solution on a single nucleation site, promoting the production of larger grain size and higher quality perovskite crystals. Exemplarily, the mass concentration of the additive is 0.4 mg / mL, 0.5 mg / mL, 0.55 mg / mL, 0.6 mg / mL, 0.7 mg / mL, etc.

[0051] Moreover, when a cationic solution is coated on the lead halide skeleton layer, the cationic solution will then react with the lead halide and additives to form an intermediate phase of the perovskite material. The presence of the intermediate phase helps to slow down the crystallization rate of the perovskite crystal, thereby promoting the full reaction of the cationic solution with the lead halide, thereby helping to reduce the defects of the perovskite crystal and generate perovskite crystals with higher quality.

[0052] In addition, the interaction between lead ions and Lewis bases also helps to adjust the porosity of the lead halide skeleton layer, so that the lead halide skeleton layer has an appropriate porosity, which helps to promote the diffusion of cationic solution into the skeleton layer and reduce the problem of lead halide residue.

[0053] In summary, the present application prepares a lead halide skeleton layer containing additives and controls the mass concentration of the additives, thereby helping to improve the quality of lead halide crystals to a high degree, thereby helping to optimize the crystallization effect of perovskite crystals and improve the performance of perovskite solar cells.

[0054] In addition, the substrate may be a planar structure, or a pyramid structure may be provided on the substrate. When the pyramid structure is provided on the substrate, the light trapping effect of the pyramid structure can be utilized to improve the absorption and utilization rate of sunlight.

[0055] Furthermore, the applicant discovered that when a lead halide skeleton layer is prepared on a substrate having a pyramid structure, there is a large surface energy difference between the top and bottom of the pyramid structure. On the one hand, this will lead to different crystallization rates of the lead halide material at different positions, affecting the quality of the lead halide crystals; on the other hand, it will lead to poor reaction between the cationic solution and the lead halide skeleton layer, resulting in a large amount of lead halide residue.

[0056] Therefore, the present invention, by adding an additive to the lead halide skeleton layer, can generate an intermediate complex, reduce the crystallization rate of the lead halide, and thus effectively avoid the problem of poor quality of the lead halide crystals caused by the presence of the pyramid structure. In addition, the Lewis base can interact with the lead ions, and the existence of this interaction can make the lead halide skeleton layer have an appropriate porosity, thereby helping to promote the diffusion of the cationic solution into the skeleton layer; and by generating an intermediate phase of the perovskite material, the crystallization growth rate of the perovskite phase is slowed, which helps to promote the sufficiency of the reaction between the perovskite material and the lead halide skeleton layer. Therefore, through the synergistic reaction between the two, it helps to reduce the problem of lead halide residue.

[0057] Furthermore, the additive groups include carbonyl and amino groups. Lead ions are Lewis acids with empty d orbitals, so the lone electron pair on the nitrogen atom in the amino group can coordinate with the lead ion to form an intermediate complex. In addition, the oxygen atom in the carbonyl group can also act as a Lewis base, which can donate electrons to the empty orbital of the lead ion, thereby promoting the formation of the intermediate complex and further contributing to the production of a higher quality lead halide skeleton layer.

[0058] In addition, when the cationic solution is spin-coated on the lead halide skeleton layer, the above-mentioned groups can also passivate the lead ion defects in the perovskite layer, thereby improving the crystal quality of the perovskite layer; and when amino and carbonyl groups are incorporated into the perovskite layer, they can also improve the ion distribution and interaction of the perovskite layer, thereby inhibiting ion migration and reducing the formation of defects in the perovskite layer.

[0059] The additive includes at least one of acetamide and propionamide. When acetamide is used as the additive, the matching degree between ethyleneamine and the lead halide material is higher, which is more conducive to promoting the reaction between ethyleneamine and the lead halide material, thereby helping to generate a lead halide skeleton layer with higher quality. Specifically, the molecular structure of acetamide is

[0060] In an optional embodiment, the lead halide material and the additive are co-evaporated by a multi-element evaporation method to prepare the lead halide skeleton layer.

[0061] In another optional embodiment, as Figure 2 As shown, the steps of making a lead halide skeleton layer containing additives on a substrate include:

[0062] fabricating a skeleton layer precursor on a substrate;

[0063] The additive is coated on the skeleton layer precursor and annealed to prepare the lead halide skeleton layer.

[0064] When the preparation method is to prepare the skeleton layer precursor first and then apply the additive, the additive does not directly participate in the formation of the skeleton layer precursor. This preparation method is a re-modification process of the skeleton layer precursor. The additive can react with the skeleton layer precursor to promote the dissolution of small grains, so that the dissolved lead halide material will continue to grow on the surface of other grains, thereby promoting the formation of large grains, making the quality of the prepared lead halide skeleton layer higher.

[0065] This is because the small grains in the skeleton layer precursor have more defects, so they are more likely to react with additives, thereby forming intermediate products with the skeleton layer precursor. The formation of the intermediate product will inhibit the crystallization growth rate of the lead halide, thereby avoiding the formation of new crystal nuclei and prompting the lead halide material to continue growing on the surface of other grains, thus helping to form lead halide crystals with larger sizes.

[0066] Moreover, during the coating process, the additives that first enter the skeleton layer precursor will improve the porosity in the skeleton layer precursor, thereby increasing the porosity of the skeleton layer precursor, thereby reducing the difficulty of subsequent additives entering, and then helping to improve the sufficiency of the reaction between the skeleton layer precursor and the additives to a greater extent, which helps to improve the performance of perovskite solar cells.

[0067] Furthermore, the thickness of the skeleton layer precursor is 350nm to 470nm. When the thickness of the skeleton layer precursor is within the above range, the additive and the skeleton layer precursor are more compatible, which helps improve the quality of the resulting lead halide skeleton layer. It also helps to produce a perovskite layer with better shape retention, making the perovskite layer more compatible with the substrate structure. Exemplarily, the thickness of the lead halide skeleton layer is 350nm, 370nm, 400nm, 450nm, 470nm, etc.

[0068] Furthermore, in the step of preparing a lead halide skeleton layer containing additives on a substrate, the annealing temperature is 100°C to 150°C, and the annealing time is 10 minutes to 20 minutes. When the additive is applied to the skeleton layer precursor by a coating method, by controlling the annealing temperature and time within the above range, it is more helpful to improve the uniformity and sufficiency of the reaction between the additive and the skeleton layer precursor, ensuring that the prepared lead halide skeleton layer has a larger grain size and fewer defects, thereby helping to further improve the crystallization quality of the perovskite layer. For example, the annealing temperature is 100°C, 125°C, 130°C, 140°C, 150°C, and the annealing time is 10 minutes, 12 minutes, 14 minutes, 16 minutes, 20 minutes, etc.

[0069] Furthermore, in the step of coating the additive on the skeleton layer precursor, the spin coating time is 20 seconds to 35 seconds, and the spin coating speed is 3000 rpm to 5000 rpm. By controlling the coating time and speed within the above ranges, the additive is uniformly coated on the skeleton layer precursor, and an appropriate amount of additive can be provided, thereby ensuring sufficient reaction between the skeleton layer precursor and the additive, thereby facilitating the preparation of a high-quality lead halide skeleton layer.

[0070] Among them, when the thickness of the skeleton precursor layer is 455nm~650nm, the parameters for controlling the coating of the additive are within the above range, so that the content of the additive is more compatible with the thickness of the skeleton layer precursor, which is more conducive to promoting the formation of perovskite solar cells with higher photoelectric conversion efficiency.

[0071] For example, the spin coating time is 20s, 22s, 25s, 30s, 35s, etc.; the spin coating speed is 3000rpm, 3500rpm, 4000rpm, 4500rpm, 5000rpm, etc.

[0072] Furthermore, the cationic solution includes at least one of formamidine iodide, methylammonium bromide and methylammonium chloride, wherein the concentration of formamidine iodide in the cationic solution is 30 mg / mL to 50 mg / mL, the concentration of methylammonium bromide in the cationic solution is 3 mg / mL to 6 mg / mL, and the concentration of methylammonium chloride in the cationic solution is 7 mg / mL to 14 mg / mL.

[0073] When the cationic solution includes the above types, it has a high compatibility with the lead halide skeleton layer and can effectively optimize the quality of the perovskite crystal by improving the crystallization quality of the lead halide skeleton layer. When the concentration of the cationic solution is within the above range, the compatibility between the cationic solution and the lead halide skeleton layer is even higher, which further helps to improve the quality of the perovskite crystal.

[0074] In addition, the cationic solution is coated on the lead halide skeleton layer, and the annealing temperature is 130°C to 140°C, and the annealing time is 25min to 35min. When the annealing temperature and time are within the above range, it is beneficial to remove volatile substances in the perovskite layer, facilitate the reaction between the cationic solution and the lead halide skeleton layer, promote the formation of the perovskite intermediate phase, effectively slow down the crystallization rate of the perovskite crystal, and further improve the crystallization quality of the perovskite layer. For example, the annealing temperature of the perovskite layer is 130°C, 132°C, 134°C, 138°C, 140°C, and the annealing time is 25min, 27min, 30min, 32min, 34min, 35min, etc.

[0075] Furthermore, the thickness of the perovskite layer is 500nm to 700nm. When the thickness of the perovskite layer is within this range, it not only helps improve the diffusion path of carriers and reduces their recombination in the perovskite layer, thereby helping to improve the photoelectric conversion efficiency of the perovskite cell; it also helps absorb more sunlight, thereby providing more photogenerated carriers. For example, the thickness of the perovskite layer is 500nm, 550nm, 600nm, 650nm, 700nm, etc.

[0076] In a second aspect, an embodiment of the present application discloses a perovskite solar cell, which is prepared by the preparation method of the first aspect.

[0077] Furthermore, the perovskite raw material for preparing the perovskite layer includes lead halide, and in the perovskite layer, the ratio of the peak intensity of the characteristic diffraction peak of the lead halide to the characteristic diffraction peak of the 001 crystal plane of the perovskite crystal is 0.076-0.23.

[0078] When the ratio of the peak intensity of the characteristic diffraction peak of lead halide to the characteristic diffraction peak of the 001 crystal plane of the perovskite crystal is within the above range, it indicates that the reaction degree between the lead halide and the cationic solution of the perovskite solar cell is high and the lead halide residue is low, which helps to improve the performance of the perovskite solar cell.

[0079] In an optional embodiment, as Figure 3 and Figure 4 As shown, the perovskite solar cell is a stacked cell, the substrate 1 includes a bottom cell 11, an electron-hole combination layer 12 provided on the bottom cell 11, and a first transport layer 13, the perovskite layer 2 is provided on the side of the first transport layer 13 away from the electron-hole combination layer 12, the perovskite solar cell further includes a second transport layer 3 and a transparent conductive layer 4 sequentially provided on the side of the perovskite layer 2 away from the first transport layer 13, the perovskite solar cell further includes a first electrode 5 and a second electrode 6, the first electrode 5 is in ohmic contact with the transparent conductive layer 4, and the second electrode 6 is in ohmic contact with the bottom cell 11, wherein one of the first transport layer 13 and the second transport layer 3 is an electron transport layer and the other is a hole transport layer, one of the first electrode 5 and the second electrode 6 is a positive electrode and the other is a negative electrode.

[0080] The material of the electron-hole recombination layer 12 includes at least one of indium tin oxide and indium zinc oxide, and the thickness of the electron-hole recombination layer 12 is 20 nm to 30 nm. When the thickness of the electron-hole recombination layer 12 is within the above range, it can effectively ensure that the layer can effectively separate electrons and holes, while also providing a suitable carrier transmission distance and reducing carrier recombination. Exemplary thicknesses of the electron-hole recombination layer 12 are 20 nm, 24 nm, 26 nm, 28 nm, 30 nm, etc.

[0081] The hole transport layer can be made of nickel oxide, with a thickness of 20 nm to 30 nm. When the hole transport layer is within this range, it can effectively collect holes while providing a suitable carrier transport distance, thereby reducing carrier recombination. Exemplary thicknesses include 20 nm, 24 nm, 26 nm, 28 nm, and 30 nm.

[0082] The material of the electron transport layer can be C 60 , with a thickness of 15nm to 20nm. When the electron transport layer's thickness is within this range, it can effectively collect electrons while providing a suitable carrier transport distance and reducing carrier recombination. Exemplary thicknesses include 15nm, 16nm, 17nm, 19nm, and 20nm.

[0083] The material of transparent conductive layer 4 includes at least one of indium tin oxide and indium zinc oxide, and the thickness of transparent conductive layer 4 is 80 nm to 120 nm. When the thickness of transparent conductive layer 4 is within this range, it can effectively ensure the conductivity of the perovskite solar cell while ensuring high sunlight transmittance. For example, the thickness of electron-hole recombination layer 12 is 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, etc.

[0084] The first and second electrodes 5 and 6 are made of at least one of silver and copper, with a thickness of 150 nm to 300 nm. When the electrode thickness is within this range, it effectively ensures a low resistance for the perovskite solar cell and helps improve the perovskite solar cell's absorption and utilization efficiency of sunlight. For example, the thickness of the first electrode 5 is 150 nm, 200 nm, 250 nm, 300 nm, etc.; the thickness of the second electrode 6 is 150 nm, 200 nm, 250 nm, 300 nm, etc.

[0085] Optionally, see Figure 4 The perovskite solar cell further includes a passivation layer 7 disposed between the perovskite layer 2 and the second transport layer 3. The material of the passivation layer 7 includes n-octylamine hydroiodide. By disposing the passivation layer 7 between the perovskite layer 2 and the second transport layer 3, the passivation layer 7 can effectively passivate the interface defects of the perovskite layer 2, improve the compatibility between the perovskite layer 2 and the second transport layer 3, and thus help further improve the performance of the perovskite solar cell.

[0086] Optionally, see Figure 4 The perovskite solar cell also includes a buffer layer 8, which is disposed between the second transmission layer 3 and the transparent conductive layer 4. The buffer layer 8 is made of tin dioxide and has a thickness of 20 nm to 30 nm. When the thickness of the buffer layer 8 is within the above range, it can effectively protect the second transmission layer 3 and the perovskite layer 2, preventing damage to the second transmission layer 3 and the perovskite layer 2 during the preparation of the transparent conductive layer 4, which would lead to a decrease in the performance of the perovskite solar cell. For example, the thickness of the buffer layer 8 is 20 nm, 24 nm, 26 nm, 30 nm, etc.

[0087] Optionally, see Figure 4 The perovskite solar cell also includes an anti-reflection layer 9, which is disposed on the side of the transparent conductive layer 4 facing away from the second transmission layer 3. The anti-reflection layer 9 is made of at least one of magnesium fluoride and lithium fluoride and has a thickness of 100 nm to 120 nm. When the thickness of the anti-reflection layer 9 is within the above range, it can effectively achieve an anti-reflection effect and significantly improve the absorption and utilization efficiency of sunlight. For example, the thickness of the anti-reflection layer 9 is 100 nm, 110 nm, 120 nm, etc.

[0088] In another optional embodiment, as Figure 5 As shown, the perovskite solar cell is a single-junction cell, the substrate 1 includes a transparent conductive substrate 14 and a first transport layer 13 provided on the transparent conductive substrate 14, the perovskite layer 2 is provided on the side of the first transport layer 13 facing away from the transparent conductive substrate 1, the solar cell further includes a second transport layer 3 provided on the side of the perovskite layer 2 facing away from the first transport layer 13, the perovskite solar cell further includes a first electrode 5 and a second electrode 6, the first electrode 5 is in ohmic contact with the second transport layer 3, and the second electrode 6 is in ohmic contact with the transparent conductive substrate 1, wherein one of the first transport layer 13 and the second transport layer 3 is an electron transport layer and the other is a hole transport layer, and one of the first electrode 5 and the second electrode 6 is a positive electrode and the other is a negative electrode.

[0089] In a third aspect, an embodiment of the present application discloses a photovoltaic module, which includes: a perovskite solar cell as described in the second aspect.

[0090] The technical solution of the present application will be further explained below in conjunction with more specific embodiments and experimental test results.

[0091] Example 1:

[0092] This embodiment provides a method for preparing the stacked perovskite solar cell:

[0093] A bottom battery with a velvet structure is provided, and a 20nm thick indium tin oxide electron-hole composite layer and a 20nm thick nickel oxide hole transport layer are sequentially prepared on the N-side of the bottom battery by magnetron sputtering.

[0094] Producing a lead halide skeleton layer containing additives on a substrate:

[0095] forming a 400 nm thick lead iodide skeleton layer precursor on a substrate;

[0096] Acetamide with a mass concentration of 0.5 mg / mL is coated on the skeleton layer precursor and annealed to prepare a lead halide skeleton layer; wherein, the spin coating time is 30 seconds, the spin coating speed is 4000 rpm, the annealing temperature is 130° C., and the time is 15 minutes.

[0097] A cationic solution is coated on the lead halide skeleton layer and annealed at a temperature of 135° C. for 30 minutes to obtain a perovskite layer with a thickness of 600 nm. The cationic solution includes formamidine iodide with a mass concentration of 35 mg / mL, methylammonium bromide with a mass concentration of 5 mg / mL, and methylammonium chloride with a mass concentration of 10 mg / mL.

[0098] The post-processing steps to obtain perovskite solar cells include:

[0099] A passivation layer is prepared on the perovskite layer using a slit coating process, and the material of the passivation layer is n-octylamine hydroiodide;

[0100] The C layer with a thickness of 18 nm was prepared on the passivation layer by evaporation process. 60 electron transport layer;

[0101] A 24nm thick tin oxide buffer layer was deposited on the electron transport layer by atomic layer deposition; a 100nm thick indium zinc oxide transparent conductive layer was deposited on the buffer layer by magnetron sputtering.

[0102] A 100nm thick silver first electrode was prepared by evaporation on the transparent conductive layer, and a 100nm thick silver second electrode was prepared by evaporation on the backlight surface of the bottom battery. The first electrode was a positive electrode and the second electrode was a negative electrode.

[0103] A 110 nm thick lithium fluoride anti-reflection layer was prepared by evaporation on the transparent conductive layer.

[0104] Example 2:

[0105] The only difference between this embodiment and Example 1 is that the mass concentration of the additive is 0.4 mg / mL.

[0106] Example 3:

[0107] The only difference between this embodiment and Example 1 is that the mass concentration of the additive is 0.7 mg / mL.

[0108] Example 3:

[0109] The only difference between this embodiment and Example 1 is that the thickness of the skeleton layer precursor is 350 nm.

[0110] Example 4:

[0111] The only difference between this embodiment and Example 1 is that the thickness of the skeleton layer precursor is 470 nm.

[0112] Embodiment 5:

[0113] The only difference between this embodiment and Example 1 is that the thickness of the skeleton layer precursor is 550 nm.

[0114] Example 6:

[0115] The only difference between this embodiment and Example 1 is that the type of additive is propionamide.

[0116] Comparative Example 1:

[0117] The only difference between this comparative example and Example 1 is that the mass concentration of the additive is 0.3 mg / mL.

[0118] Comparative Example 2:

[0119] The only difference between this comparative example and Example 1 is that the mass concentration of the additive is 0.8 mg / mL.

[0120] Comparative Example 3:

[0121] The only difference between this comparative example and Example 1 is that no additive is added to the lead halide skeleton layer, that is, after the skeleton layer precursor is evaporated, the cationic solution is directly coated on the skeleton layer precursor.

[0122] Performance testing:

[0123] The following tests were performed on the solar cells prepared in Examples 1 to 6 and Comparative Examples 1 to 3:

[0124] This application uses a Wavelabs solar simulator to perform open circuit voltage, short circuit current, and fill factor performance tests on a perovskite solar cell. The halm machine is a device that simulates sunlight, and is equipped with an electronic load, data acquisition and calculation equipment to test the electrical properties of photovoltaic devices (including solar cells, such as Eta, Voc, Jsc, FF, etc., which are used to reflect the performance of solar cells. Test conditions: AM1.5, 1000W / m 2 The test environment temperature is 25℃ and the effective area of ​​the battery is 20.38cm 2 The experimental test results are as follows, where Voc represents the open circuit voltage, Jsc represents the short circuit current density, FF represents the fill factor, and Eta represents the photoelectric conversion efficiency. The experimental test results are shown in Table 1.

[0125] Table 1 Performance test results of perovskite solar cells

[0126] Experimental conditions Photoelectric conversion rate (%) Open circuit voltage (V) Short-circuit current (A) Fill factor (%) Example 1 27.22 1.897 20.48 70.07 Example 2 27.07 1.895 20.46 69.82 Example 3 26.96 1.898 21.22 66.91 Example 4 26.88 1.899 20.9 67.72 Example 5 26.56 1.892 20.97 66.91 Example 6 26.42 1.892 20.94 66.67 Comparative Example 1 26.35 1.884 21.01 66.6 Comparative Example 2 26.06 1.893 21.04 65.42 Comparative Example 3 25.8 1.897 20.9 65.08

[0127] Analysis of the data from Examples 1 to 3 and Comparative Examples 1 and 2 shows that the photoelectric conversion efficiency of Examples 1 to 3 is superior to that of Comparative Examples 1 and 2. This indicates that when the additive concentration is within the range of 0.4 mg / mL to 0.7 mg / mL, acetamide can bind to the lead halide material to a high degree, thereby reducing the crystal growth rate of the lead halide and inhibiting lead halide nucleation, thereby ensuring that the prepared lead halide has a larger grain size, fewer grain boundaries, and fewer defects.

[0128] Analysis of the data from Example 1 and Comparative Example 3 shows that the photoelectric conversion efficiency of Example 1 is superior to that of Comparative Example 3. This indicates that the introduction of the acetamide additive into the lead halide skeleton layer effectively optimizes the crystallization quality of the lead halide skeleton layer, thereby ensuring the preparation of a perovskite layer with high crystallization quality.

[0129] Analysis of the data from Examples 1, 3, and 5 shows that the photoelectric conversion efficiency of Examples 1, 3, and 4 is better than that of Example 5. This indicates that the thickness of the skeleton layer precursors in Examples 1, 3, and 4 is more compatible with the mass concentration of the additives, which facilitates the preparation of higher-quality lead halide skeleton layers, and thus facilitates the preparation of perovskite crystals with larger grain sizes and smaller defects.

[0130] Analysis of the data of Example 1 and Example 6 shows that the photoelectric conversion efficiency of Example 1 is better than that of Example 6. This shows that when acetamide is used as an additive, the acetamide has a higher compatibility with the skeleton layer precursor, and a higher compatibility is more conducive to obtaining a higher quality lead halide skeleton layer.

[0131] The above is a detailed introduction to the perovskite solar cell, its preparation method, and photovoltaic module disclosed in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the perovskite solar cell, its preparation method, and photovoltaic module: At the same time, for those skilled in the art, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The preparation method comprises: Producing a lead halide skeleton layer containing an additive on a substrate, wherein the additive is a Lewis base and the mass concentration of the additive in the lead halide skeleton layer is 0.4 mg / mL to 0.7 mg / mL; coating a cationic solution on the lead halide skeleton layer and annealing to obtain a perovskite layer; After post-processing, the perovskite solar cell is obtained.

2. The preparation method according to claim 1, characterized in that The groups of the additive include carbonyl and amino groups.

3. The preparation method according to claim 1, characterized in that The step of making a lead halide skeleton layer containing additives on a substrate comprises: preparing a skeleton layer precursor on the substrate; The additive is coated on the skeleton layer precursor and annealed to obtain the lead halide skeleton layer.

4. The preparation method according to claim 3, characterized in that The thickness of the skeleton layer precursor is 350nm to 470nm.

5. The preparation method according to claim 3, characterized in that In the step of preparing the lead halide skeleton layer containing additives on the substrate, the annealing temperature is 100° C. to 150° C., and the annealing time is 10 min to 20 min.

6. The preparation method according to claim 3, characterized in that In the step of coating the additive on the skeleton layer precursor, the spin coating time is 20s to 35s; the spin coating speed is 3000rpm to 5000rpm.

7. The preparation method according to any one of claims 1 to 6, characterized in that The additive includes at least one of acetamide and propionamide; and / or, The cationic solution comprises at least one of formamidine iodide, methylammonium bromide, and methylammonium chloride, wherein the concentration of the formamidine iodide in the cationic solution is 30 mg / mL to 50 mg / mL, the concentration of the methylammonium bromide in the cationic solution is 3 mg / mL to 6 mg / mL, and the concentration of the methylammonium chloride in the cationic solution is 7 mg / mL to 14 mg / mL; and / or, A pyramid structure is provided on the substrate; and / or, The cationic solution is coated on the lead halide skeleton layer, and the annealing temperature is 130° C. to 140° C., and the annealing time is 25 min to 35 min; The thickness of the perovskite layer is 455nm-650nm.

8. A perovskite solar cell, characterized in that: The perovskite solar cell is prepared by the preparation method according to any one of claims 1 to 7.

9. The solar cell according to claim 8, characterized in that The perovskite raw material used to prepare the perovskite layer includes lead halide. In the perovskite layer, the ratio of the peak intensity of the characteristic diffraction peak of the lead halide to the characteristic diffraction peak of the 001 crystal plane of the perovskite crystal is 0.076-0.

23.

10. The perovskite solar cell according to claim 8, characterized in that: The perovskite solar cell is a stacked cell, the substrate includes a bottom cell, an electron-hole combination layer provided on the bottom cell, and a first transport layer, the perovskite layer is provided on the side of the first transport layer away from the electron-hole combination layer, the perovskite solar cell further includes a second transport layer and a transparent conductive layer provided in sequence on the side of the perovskite layer away from the first transport layer, the perovskite solar cell further includes a first electrode and a second electrode, the first electrode is in ohmic contact with the transparent conductive layer, and the second electrode is in ohmic contact with the bottom cell, wherein one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode; Alternatively, the perovskite solar cell is a single-junction cell, the substrate includes a transparent conductive substrate and a first transport layer provided on the transparent conductive substrate, the perovskite layer is provided on the side of the first transport layer facing away from the transparent conductive substrate, the solar cell also includes a second transport layer provided on the side of the perovskite layer facing away from the first transport layer, the perovskite solar cell also includes a first electrode and a second electrode, the first electrode is in ohmic contact with the second transport layer, and the second electrode is in ohmic contact with the transparent conductive substrate, wherein one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, and one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode.

11. A photovoltaic module, characterized in that: The photovoltaic module comprises: the perovskite solar cell according to any one of claims 8 to 10.

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