Solar cell and preparation method thereof, photovoltaic module, power utilization device and power generation device

Abstract

The invention relates to a solar cell and a preparation method thereof, a photovoltaic module, a power utilization device and a power generation device. The solar cell comprises a first electrode and a perovskite layer which are stacked. The first electrode comprises fluorine-doped tin oxide; the fluorine-doped tin oxide comprises an FTO (fluorine-doped tin oxide) crystal phase, and the FTO crystal phase comprises an FTO (110) crystal face; the perovskite layer comprises a perovskite crystal phase, and the perovskite crystal phase comprises a perovskite dominant crystal face; the first electrode comprises a first surface far away from the perovskite layer, the perovskite layer comprises a second surface far away from the first electrode, and a region from the first surface to the second surface in the solar cell is marked as a first structural region; based on an XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the advantageous crystal face of the perovskite to the diffraction peak of the FTO (110) crystal face is recorded as M1, and M1 is greater than or equal to 5. The solar cell provided by the invention has relatively good photoelectric conversion efficiency.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to solar cells and their preparation methods, photovoltaic modules, electrical devices, and power generation devices. Background Technology

[0002] Perovskite solar cells are devices that convert solar energy into electrical energy using the photoelectric conversion mechanism of perovskite crystalline materials. They represent the third generation of solar cells and, with their advantages such as high conversion efficiency, fast response speed, long lifespan, low energy consumption, small size, and environmental friendliness, have shown enormous development potential in the photovoltaic field. However, the photoelectric conversion efficiency of perovskite solar cells still needs further improvement. Summary of the Invention

[0003] In view of the above problems, this application provides a solar cell with improved photoelectric conversion efficiency and a method for preparing the same, as well as a photovoltaic module, an electrical device, and a power generation device.

[0004] In a first aspect, this application provides a solar cell, including a first electrode and a perovskite layer stacked together; the first electrode includes fluorine-doped tin oxide; the fluorine-doped tin oxide includes an FTO crystal phase, the FTO crystal phase including an FTO (110) crystal plane; the perovskite layer includes a perovskite crystal phase, the perovskite crystal phase including a perovskite dominant crystal plane;

[0005] The first electrode includes a first surface remote from the perovskite layer, and the perovskite layer includes a second surface remote from the first electrode. The region from the first surface to the second surface in the solar cell is referred to as the first structural region.

[0006] Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (110) crystal plane is denoted as M1, where M1≥5; wherein, X-rays are incident on the first structural region from the second surface to the first surface.

[0007] The FTO (110) crystal plane is a common reference peak in the fluorine-doped tin oxide (FTO) crystal phase. Its intensity is stable and can be used to characterize the relative content of the main FTO crystal phase in the first electrode. By controlling the peak height ratio (M1) of the diffraction peak of the perovskite dominant crystal plane to that of the FTO (110) crystal plane within the aforementioned range, the perovskite dominant crystal plane can be controlled to have a higher proportion in the perovskite layer. At this time, the crystal quality of the perovskite layer is higher and there are fewer defects, which can reduce non-radiative recombination and is beneficial to carrier transport. At the same time, by controlling M1 within the aforementioned range, from the projection plane in the thickness direction of the perovskite layer from the second surface to the first surface, the exposure degree of FTO in the first electrode can also be controlled to be lower. This is beneficial to reduce carrier recombination caused by surface defects due to FTO exposure, prolong carrier lifetime and enhance effective carrier collection. Thus, the macroscopic photoelectric conversion efficiency is improved.

[0008] It is understandable that we do not wish to be limited to the aforementioned theories. For example, by controlling the exposure level of FTO in the first electrode to be low, it is also beneficial to reduce the risk of electrode corrosion and interfacial contact, thereby improving the performance reliability of solar cells.

[0009] In some embodiments, M1 is 5 to 15, and may be 5 to 12.

[0010] At this point, the dominant perovskite crystal plane has a high proportion in the perovskite layer, the perovskite layer has high crystal quality and few defects, which can reduce non-radiative recombination and is conducive to carrier transport; at the same time, the FTO in the first electrode has a low exposure degree, which is conducive to reducing carrier recombination caused by surface defects due to FTO exposure, extending carrier lifetime and enhancing effective carrier collection; thus, the macroscopic photoelectric conversion efficiency is improved.

[0011] In some embodiments, the dominant perovskite crystal plane is the perovskite (100) crystal plane.

[0012] The perovskite (100) crystal plane has a low defect state density and a high carrier lifetime, which is beneficial for reducing defect density, improving carrier and charge transport efficiency, and thus improving the photoelectric conversion efficiency of solar cells.

[0013] In some embodiments, the perovskite crystal phase further includes a perovskite (110) crystal plane;

[0014] Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite (100) crystal plane to the diffraction peak of the perovskite (110) crystal plane is denoted as M2, where M2≥5 and can be selected as M2≥8.

[0015] The dense atomic arrangement and high compactness of the perovskite (110) crystal facet are beneficial for reducing ion migration and improving reliability. Furthermore, by controlling M2 within the above range, the proportion of the dominant perovskite (100) crystal facet in the perovskite crystal phase is high, resulting in high crystal quality and fewer defects in the perovskite layer. This reduces non-radiative recombination and is beneficial for carrier transport. At the same time, it can combine the advantages of the perovskite (110) crystal facet to improve the compactness of the perovskite layer. This balances carrier transport efficiency, defect density, and ion migration, thereby improving the photoelectric conversion efficiency of the solar cell.

[0016] In some embodiments, M2 is 5 to 28, optionally 8 to 28, and further optionally 8 to 25.

[0017] At this point, the proportion of the dominant perovskite (100) crystal plane in the perovskite crystal phase is high, the crystal quality of the perovskite layer is high and there are few defects, which can reduce non-radiative recombination and is conducive to carrier transport. At the same time, it can combine the advantages of the perovskite (110) crystal plane to improve the compactness of the perovskite layer, thereby taking into account the carrier transport efficiency, defect density and ion migration degree, and thus better improving the photoelectric conversion efficiency of the solar cell.

[0018] In some embodiments, the fluorine-doped tin oxide further includes an FTO (200) crystal plane;

[0019] Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (200) crystal plane is denoted as M3, where M3 ≥ 6.

[0020] The FTO (200) crystal plane is also a common crystal plane reference peak in the fluorine-doped tin oxide (FTO) crystal phase. Its intensity is stable and can be used to characterize the relative content of the main FTO crystal phase in the first electrode. By controlling the peak height ratio (M3) of the diffraction peak of the perovskite dominant crystal plane to that of the FTO (200) crystal plane within the aforementioned range, the perovskite dominant crystal plane can be controlled to have a higher proportion in the perovskite layer. At this time, the crystal quality of the perovskite layer is higher and there are fewer defects, which can reduce non-radiative recombination and is beneficial to carrier transport. At the same time, by controlling M3 within the aforementioned range, from the projection plane in the thickness direction of the perovskite layer from the second surface to the first surface, the exposure degree of FTO in the first electrode can also be controlled to be lower. This is beneficial to reduce carrier recombination caused by surface defects due to FTO exposure, prolong carrier lifetime and enhance effective carrier collection. Thus, the macroscopic photoelectric conversion efficiency is improved.

[0021] In some embodiments, the perovskite crystal phase includes a perovskite (100) crystal plane, and the average thickness of the perovskite (100) crystal plane in the normal direction is denoted as D. 100 D100 ≥600Å; optionally, 600Å≤D 100 ≤1000Å.

[0022] The average thickness of the perovskite (100) crystal plane in the normal direction is within the above range. The growth of the perovskite phase in the direction of the perovskite (100) crystal plane is more complete, the corresponding perovskite phase has higher crystallinity, fewer defects, and greater carrier mobility and diffusion length, which is beneficial to reduce nonradiative recombination and thus improve photoelectric conversion efficiency.

[0023] In some embodiments, the perovskite crystal phase includes a perovskite (110) crystal plane, and the average thickness of the perovskite (110) crystal plane in the normal direction is denoted as D. 110 D 110 ≥ 200Å; optionally, 200Å ≤ D 110 ≤385Å.

[0024] The average thickness of the perovskite (110) crystal plane in the normal direction is within the above range. The growth of the perovskite phase in the direction of the perovskite (110) crystal plane is more complete, and the corresponding perovskite phase has higher crystallinity, fewer defects, and a more compact arrangement. This can reduce non-radiative recombination and ion migration, improve carrier transport efficiency, and improve the photoelectric conversion efficiency of solar cells.

[0025] In some embodiments, the thickness of the perovskite layer is denoted as H, and the region extending d1 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the first region, where H / 10-20nm≤d1≤H / 10+20nm;

[0026] The average crystallinity of the perovskite phase in the first region is less than the average crystallinity of the perovskite phase in the perovskite layer.

[0027] By controlling the average crystallinity of the first region to be less than that of the perovskite layer, the first region has smaller grains, more grain boundaries and amorphous phases, which can serve as recombination centers, preferentially absorb charge carriers and ions, help to hinder the longitudinal migration of ions, and obtain a high-quality bulk phase, thereby improving the photoelectric conversion efficiency of solar cells.

[0028] In some embodiments, based on the XRD diffraction pattern of the first structural region, the ratio of the full width at half maximum (FWHM) of the diffraction peak of the dominant perovskite crystal plane in the first region to the FWHM of the diffraction peak of the dominant perovskite crystal plane in the perovskite layer is denoted as M4, where M4 is 1:(0.3~0.8).

[0029] By controlling the ratio of the full width at half maximum (FWHM) of the diffraction peaks of the dominant perovskite crystal plane in the first region to that of the perovskite layer within the aforementioned range, on the one hand, the average crystallinity of the perovskite phase in the first region of the perovskite layer is lower than that in the perovskite layer itself. The first region has smaller grains, more grain boundaries, and amorphous phases, which can serve as recombination centers, preferentially absorbing charge carriers and ions, thus hindering the vertical migration of ions and resulting in a high-quality bulk phase. On the other hand, a moderate difference between the average crystallinity of the perovskite phase in the first region and that in the perovskite layer leads to better overall uniformity of the perovskite layer. This helps reduce performance inhomogeneities caused by local lattice distortion or defect aggregation, promoting the extraction and transport of charge carriers. This, in turn, improves the photoelectric conversion efficiency of the solar cell.

[0030] In some embodiments, the full width at half maximum (FWHM) of the diffraction peaks of the dominant perovskite crystal plane of the perovskite layer is 0.085° to 0.131°.

[0031] At this point, the diffraction peaks of the perovskite (100) crystal plane in the perovskite layer have a smaller half-width at half-maximum (HWHM), indicating higher crystallinity of the perovskite phase. This suggests that the perovskite phase has a more regular crystal structure and more ordered atomic arrangement, which helps to reduce grain boundaries and defects in the perovskite layer, reduce the probability of nonradiative recombination of charge carriers, and improve the carrier mobility. Simultaneously, the HWHM being controlled within the aforementioned range also indicates a more uniform crystal orientation, which is beneficial for reducing scattering and trapping effects of charge carriers during transport, thus improving the overall carrier transport rate. Therefore, the photoelectric conversion efficiency of the solar cell is improved.

[0032] In some embodiments, the perovskite layer comprises a first perovskite material, the first perovskite material comprising FA. 1-x1 Cs x1 PbBr x2 I 3-x2 Where x1 is 0~0.8 and x2 is 0~0.8.

[0033] Formamidinium groups possess excellent light absorption and carrier transport properties. Iodide ions have a large radius, which can expand the lattice and help adjust the band gap. Iodide ions also facilitate the formation of perovskite materials with symmetrical crystal phase structures, reducing local strain and defect density, and lowering the resistivity of perovskite materials, thus improving photoelectric conversion efficiency. Meanwhile, Cs⁺ and bromide ions have small radii, which help shrink the lattice, reduce the strain gradient, and improve crystal structure uniformity, further enhancing the photoelectric conversion efficiency of solar cells.

[0034] In some embodiments, the thickness of the perovskite layer is 200nm~1000nm, and can be selected as 300nm~600nm.

[0035] This facilitates the absorption, transport, and collection of charge carriers, thereby improving the photoelectric conversion efficiency of optoelectronic devices and / or reducing costs.

[0036] In some embodiments, the area of ​​the perovskite layer is greater than or equal to 0.07 m² in a direction perpendicular to the thickness of the perovskite layer. 2 This will help improve the efficiency of solar cells and reduce costs.

[0037] In some embodiments, the solar cell is a multi-junction solar cell, which includes a first cell unit, the first cell unit including the perovskite layer.

[0038] The aforementioned perovskite layer can be incorporated into multi-junction solar cells to improve the photoelectric conversion efficiency and device stability of multi-junction solar cells.

[0039] In some embodiments, the multijunction solar cell further includes a second cell stacked with the first cell; the second cell and the first cell are connected by an interconnect layer, or the second cell and the first cell are isolated by an insulating layer; the second cell includes a second light-absorbing layer, and the band gap of the second light-absorbing layer is different from that of the perovskite layer.

[0040] When solar cells are multi-junction solar cells, they are beneficial for improving the utilization rate of incident light, while also possessing the aforementioned advantages of high photoelectric conversion efficiency and high device stability. Multi-junction solar cells can be monolithic integrated tandem solar cells or mechanically tandem solar cells, offering flexibility in form and a wide range of applications.

[0041] In some embodiments, the second light-absorbing layer in the second battery cell includes a semiconductor active material, which includes one or more of the following: a second perovskite material, a silicon-containing semiconductor material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, gallium arsenide, and organic active materials.

[0042] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0043] In some embodiments, the multi-junction solar cell includes a first electrode, a perovskite layer, a carrier recombination layer or tunneling layer, a second light-absorbing layer, and a second electrode stacked together; wherein the interconnect layer is located between the perovskite layer and the second light-absorbing layer; the first electrode is located on the side of the perovskite layer opposite to the interconnect layer, and the second electrode is located on the side of the second light-absorbing layer opposite to the interconnect layer. Thus, two cell units in the multi-junction solar cell are connected through the interconnect layer to achieve current matching between the two cell units, resulting in a relatively smaller size, the ability to absorb light of different wavelengths, a wider absorption spectrum range of the multi-junction solar cell, and improved photoelectric conversion efficiency. In some embodiments, a hole transport layer is disposed between the first electrode and the perovskite layer.

[0044] In some embodiments, the multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, the insulating layer, and the fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is disposed on the side of the insulating layer facing the perovskite layer, the fourth electrode is disposed on the side of the insulating layer facing the second light-absorbing layer, the first electrode is located on the side of the perovskite layer away from the third electrode, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode. Thus, the multi-junction solar cell forms a mechanically stacked cell. The insulating layer isolates the two cell units, preventing direct conduction of charge carriers and eliminating the need for current matching. Furthermore, each cell has its own separate positive and negative electrodes for current extraction, allowing for flexible circuit adjustments. In some embodiments of this application, a hole transport layer is provided between the first electrode and the perovskite layer.

[0045] In some embodiments, one or more of the following features are satisfied:

[0046] (1) The perovskite layer is contained in the inverse or formal structure of the solar cell;

[0047] (2) The solar cell includes a first transport layer and a second transport layer, and the perovskite layer is stacked between the first transport layer and the second transport layer; wherein, one of the first transport layer and the second transport layer is a hole transport layer and the other is an electron transport layer.

[0048] The perovskite layer is incorporated into either the inverted or conventional structure. The aforementioned embodiments can be universally applied to solar cells of both conventional and inverted structures, improving photoelectric conversion efficiency and device stability. Furthermore, the aforementioned advantages of the perovskite layer are independent of the positional relationship between the hole transport layer and the electron transport layer stacked with it, allowing these advantages to be utilized in devices with different structures.

[0049] Secondly, this application provides a method for preparing a solar cell, comprising the following steps:

[0050] A first wet film is formed on a first substrate by a first solution containing a perovskite precursor, and then dried and subjected to a first annealing treatment to form a perovskite base film; the first substrate includes a first electrode, the first electrode including fluorine-doped tin oxide; the fluorine-doped tin oxide includes an FTO crystal phase, the FTO crystal phase including an FTO (110) crystal plane;

[0051] The second solution containing the first additive is atomized and deposited on the surface of the perovskite-based film to form a second wet film. After a second annealing treatment, a perovskite layer is formed.

[0052] The first additive includes at least one of fluorine-containing organic materials and sulfur-containing organic materials, the first annealing treatment time is 2 min to 8 min, and the first annealing treatment temperature is 120℃ to 150℃.

[0053] The perovskite layer includes a perovskite crystal phase, and the perovskite crystal phase includes a perovskite dominant crystal plane; the first electrode includes a first surface away from the perovskite layer, and the perovskite layer includes a second surface away from the first electrode. The region from the first surface to the second surface in the solar cell is denoted as the first structural region. Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (110) crystal plane is denoted as M1, where M1 ≥ 5. X-rays are incident on the first structural region from the direction from the second surface to the first surface.

[0054] Fluorine-containing and sulfur-containing organic additives can effectively passivate surface defects and reduce ion migration by interacting with unsaturated cations on the perovskite substrate surface through strong coordination or hydrogen bonding between fluoride / sulfide ions and fluorine / sulfide ions. When a second solution containing the first additive is atomized, a second wet film is formed on the surface of the perovskite substrate (denoted as the upper surface). The atomized droplets evaporate rapidly on the upper surface of the perovskite substrate after a very short residence time, and the first additive is instantly anchored to the upper surface and grain boundaries, rapidly reducing the surface energy of the upper surface, minimizing secondary nucleation, and allowing the crystal to continue growing downwards.

[0055] Furthermore, after the surface energy of the upper surface decreases rapidly, the nucleation on the upper surface decreases, resulting in less consumption of the first additive, leaving a relatively large amount of the first additive remaining. Under the limited temperature and time of the first annealing, the crystal growth in the perovskite substrate film is incomplete, the grain boundaries are loose and rich in defects, and it is in a metastable state. The loose, porous grain boundaries and unclosed lattice provide a diffusion channel for the first additive molecules or the active substances generated by their decomposition to diffuse directly from the upper surface to the interface between the perovskite substrate film and the first electrode (denoted as the lower interface), which can achieve three-dimensional bulk defect passivation. In particular, the first additive will preferentially deposit in the area with the weakest structure and the most defects at the lower interface, i.e., the exposed area of ​​the first electrode. The second annealing process can promote the growth of the dominant perovskite crystal facets, increase their proportion, effectively passivate defects in the perovskite layer, improve its crystal quality, and promote secondary nucleation and growth of perovskite on the surface of the first electrode, thus improving the coverage of the first electrode. As a result, the dominant perovskite crystal facets have a higher proportion in the perovskite layer, and the FTO in the first electrode has a lower exposure, thereby increasing the peak height ratio of the diffraction peaks of the dominant perovskite crystal facets to the diffraction peaks of the FTO (110) crystal facets, thereby improving the macroscopic photoelectric conversion efficiency.

[0056] In some embodiments, the step of atomizing a second solution containing a first additive and depositing it on the surface of the perovskite-based film to form a second wet film includes: atomizing the second solution containing the first additive to form an atomized second solution, and using an inert gas as a carrier gas to deposit the atomized second solution on the surface of the perovskite-based film to form a second wet film; optionally, the inert gas includes nitrogen.

[0057] This provides an oxygen-free and water-free environment, optimizes crystallization kinetics, improves the crystal quality of perovskite, and thus enhances the photoelectric conversion efficiency of solar cells. Using nitrogen as a carrier gas can reduce costs.

[0058] In some embodiments, the temperature of the second annealing treatment is 80℃~100℃, and the time of the second annealing treatment is 2min~15min, optionally 5min~10min. The above-mentioned conditions for the second annealing treatment can promote the continued growth of the dominant perovskite crystal facet, increase its proportion, and promote the effective passivation of defects in the perovskite layer by the first additive, thereby improving its crystal quality. At the same time, it can promote the secondary nucleation and growth of perovskite on the surface of the first electrode, improving the coverage of the first electrode. As a result, the dominant perovskite crystal facet has a high proportion in the perovskite layer, and the FTO in the first electrode has a low exposure degree, thereby increasing the peak height ratio of the diffraction peak of the dominant perovskite crystal facet relative to the diffraction peak of the FTO (110) crystal facet, thereby improving the macroscopic photoelectric conversion efficiency.

[0059] In some embodiments, the fluorinated passivating agent includes at least one of pentafluoroiodoethane, heptafluoro-1-iodopropane, 1-iodoperfluorodecane, and perfluorobromobutane.

[0060] The aforementioned fluorinated passivating agent can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of solar cells by interacting with unsaturated cations on the surface of perovskite-based films through strong coordination or hydrogen bonding using fluoride ions.

[0061] In some embodiments, the sulfur-containing organic additive includes at least one of thionium salts, disulfides, and organic sulfonates;

[0062] Optionally, the thioonium salt includes dimethylphenylethylmercaptoiodide; the disulfide includes 2,2'-dithionidinedimethylbis(N-methylethylamine) dihydrochloride; and the organic sulfonate includes disodium 1,4-piperazine diethanesulfonate.

[0063] The aforementioned sulfur-containing organic additives can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of solar cells by interacting with unsaturated cations on the surface of perovskite-based films through strong coordination or hydrogen bonding using sulfur ions.

[0064] In some embodiments, the first additive accounts for 0.07 wt% to 0.7 wt% of the mass of the perovskite precursor.

[0065] When the mass ratio of the first additive relative to the perovskite precursor is within the aforementioned range, on the one hand, it can effectively passivate surface defects and reduce ion migration by interacting with unsaturated cations on the perovskite layer surface through strong coordination or hydrogen bonding via fluoride / sulfide ions; on the other hand, it can reduce the risk of the first additive agglomerating and crystallizing at grain boundaries or interfaces to form a continuous insulating layer, and promote the lateral transport and vertical extraction of charge carriers between grains. This is beneficial for passivating surface defects while maintaining charge carrier transport efficiency, thereby improving the photoelectric conversion efficiency of solar cells.

[0066] In some embodiments, the atomization method includes at least one of ultrasonic atomization and pneumatic atomization. Ultrasonic atomization utilizes high-frequency vibration to generate cavitation effects in the liquid, atomizing the solution into droplets. This is beneficial for obtaining droplets with uniform size, small size, and low kinetic energy, which improves the uniformity of contact between the first additive and the perovskite layer surface, promotes the anchoring of the first additive to the perovskite layer surface and grain boundaries, and enhances the passivation effect. Pneumatic atomization utilizes high-speed airflow to atomize the solution into droplets, offering high atomization efficiency and enabling larger flow rates. This is also beneficial for the contact between the first additive and the perovskite layer surface, enhancing the passivation effect.

[0067] Thirdly, this application provides a photovoltaic module, including at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect. The aforementioned photovoltaic module has improved photoelectric conversion efficiency.

[0068] Fourthly, this application provides an electrical device comprising at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect.

[0069] The aforementioned electrical devices have improved photoelectric conversion efficiency.

[0070] Fifthly, this application provides a power generation device, including at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect.

[0071] The aforementioned power generation device has improved photoelectric conversion efficiency. Attached Figure Description

[0072] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. It should also be noted that the drawings are drawn in a simplified form and are only used to facilitate and clarify the illustration of this application. The various dimensions of each part shown in the drawings are arbitrarily shown and may be precise or not drawn to scale. For example, the dimensions of parts are appropriately exaggerated in some places in the drawings to make the illustration clearer. Unless otherwise specified, the parts in the drawings are not drawn to scale. This application does not limit every dimension of every part. In the drawings:

[0073] Figure 1 This is a schematic diagram of a solar cell structure according to an embodiment of the present application, which includes a perovskite layer, a first electrode, a first surface, and a second surface.

[0074] Figure 2 This is a schematic diagram of a solar cell structure according to an embodiment of the present application, which includes a perovskite layer, a second surface, a third surface, and a first region;

[0075] Figure 3 This is a schematic diagram of a solar cell according to an embodiment of the present application; it includes a substrate layer, a first electrode, a first transport layer, a perovskite layer, a second transport layer, and a second electrode;

[0076] Figure 4 This is a schematic diagram of a solar cell according to another embodiment of this application; it includes a substrate layer, a first electrode, a first transport layer, a perovskite layer, a second transport layer, a second electrode, a first channel region, a second channel region, and a third channel region;

[0077] Figure 5Here is a SEM image of the perovskite layer in Example 1 of this application;

[0078] Figure 6 Here is a SEM image of the perovskite layer in Example 2 of this application;

[0079] Figure 7 This is the XRD pattern of the component consisting of the perovskite layer and the first electrode in Embodiment 1 of this application.

[0080] Explanation of reference numerals in the attached figures: 100 is the solar cell; 110 is the substrate layer; 120 is the first electrode; 130 is the first transport layer; 140 is the perovskite layer; 150 is the second transport layer; 160 is the second electrode; P1 is the first channel region; P2 is the second channel region; P3 is the third channel region; 1201 is the first surface; 1401 is the first region; 1402 is the second surface; 1403 is the third surface.

[0081] It should be noted that, Figure 2 The dashed lines within the perovskite layer only indicate the positions of the first region on both sides in the thickness direction of the perovskite layer, but do not mean that the marked first region forms an interface of different phases with the adjacent part within the perovskite layer; in some embodiments, the phases on both sides shown by the dashed lines are continuously distributed. Figure 2 The middle arrow indicates the incident light side; Z indicates the thickness direction of the perovskite layer. Detailed Implementation

[0082] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the solar cell and its fabrication method, photovoltaic module, power supply device, and power generation device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0083] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0084] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0085] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0086] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0087] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0088] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0089] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0090] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0091] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," "fifth," "sixth," "seventh," and "eighth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Furthermore, "first," "second," "third," "fourth," "fifth," "sixth," "seventh," and "eighth" serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0092] In this application, substituents of compounds are disclosed by groups or ranges. It is expressly intended that such descriptions include each individual subcombination of members of these groups and ranges. For example, “C1-C4” refers to containing 1-4 carbon atoms, and it is expressly intended that the term “C1-C10” individually discloses C1, C2, C3, C4, C1-C4, C1-C3, C1-C2, C2-C4, and C2-C3. As another example, 6-18 ring atoms individually disclose each ring atom represented by an integer between 6 and 18, and the number of ring atoms forming ranges of different integers between 6 and 18, for example, the number of ring atoms could be 6, 10, 12, 14, 18, etc., or 6-14, 6-18, etc.

[0093] In this application, the term "alkyl" encompasses both straight-chain and branched alkyl groups. For example, an alkyl group may be a C1-C4 alkyl group. In some embodiments, C1-C4 alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl. Additionally, the alkyl group may be optionally substituted, for example, alkyl groups may be halogenated to form haloalkyl groups. The term "halogenated alkyl" refers to an alkyl group in which some or all of the hydrogen atoms are replaced by halogen atoms, and the term "halogen atom" refers to fluorine, chlorine, bromine, iodine, etc.

[0094] In this application, the term "alkylene" refers to an alkyl group that has lost one hydrogen atom. The definition of an alkyl group is as described above.

[0095] In this application, for a solar cell, when light can be incident on only one side in the first direction, that side is referred to as the "light-incident side"; when light can be incident on both sides of the solar cell, the side with higher device efficiency (PCE) when light is incident is defined as the "light-incident side".

[0096] In this application, the thickness direction of the perovskite layer is indicated by the Z-direction. The first and second surfaces of the perovskite layer are perpendicular or approximately perpendicular to the Z-direction.

[0097] In this application, unless otherwise specified, "solar cell" refers to a battery capable of converting solar energy into electrical energy using a photoelectric conversion mechanism. It is understood that a solar cell includes a light-absorbing layer. When the light-absorbing layer comprises perovskite material, the solar cell is a "perovskite solar cell".

[0098] When a solar cell operates, after the light-absorbing layer is exposed to light, the electrons inside gain energy and break free from the layer's binding force to form negatively charged electron carriers and positively charged hole carriers, thus creating electron-hole pairs. These free electrons and holes then travel in opposite directions through corresponding transport layers, causing them to flow. When connected to an external load, this forms a photocurrent, realizing the conversion of light energy into electrical energy. Furthermore, if the light-absorbing layer is a perovskite layer, the perovskite layer absorbs photons and is excited to generate electron-hole pairs. These pairs further dissociate to form free carriers with opposite charges. The free electrons travel through the electron transport layer to the positive electrode, while the free holes travel through the hole transport layer to the negative electrode. Both types of free carriers are collected by their respective electrodes, further generating a photocurrent in the solar cell's circuitry.

[0099] In some embodiments of this application, the electron transport layer is capable of extracting and transporting electrons and blocking the passage of free holes.

[0100] In some embodiments of this application, the hole transport layer is capable of extracting and transporting holes and blocking the passage of free electrons.

[0101] In this application, unless otherwise specified, "charge carrier" can be an electron or a hole. "Carrier pair" refers to an electron-hole pair.

[0102] In this application, for a solar cell, when light can be incident on only one side in the first direction, that side is referred to as the "light-incident side"; when light can be incident on both sides of the solar cell, the side with higher device efficiency (PCE) when light is incident is defined as the "light-incident side".

[0103] In this application, the thickness direction of the perovskite layer is designated as the Z-direction. The two opposing surfaces of the perovskite layer in the thickness direction are perpendicular or approximately perpendicular to the Z-direction.

[0104] Perovskite solar cells are devices that convert solar energy into electrical energy using the photoelectric conversion mechanism of perovskite crystalline materials. They represent the third generation of solar cells and, with their advantages of high conversion efficiency, fast response speed, long lifespan, low energy consumption, small size, and environmental friendliness, have shown great development potential in the photovoltaic field. However, the photoelectric conversion efficiency of perovskite solar cells still needs further improvement. (The last sentence appears to be a separate, unrelated thought: "From the projection plane along the thickness direction of the perovskite layer from the second surface to the first surface...")

[0105] From the projection plane along the thickness direction of the perovskite layer from the first electrode, the presence of an exposed region at the first electrode interface easily becomes a non-radiative recombination center. Photogenerated carriers (electrons and holes) readily recombine at this location, reducing carrier lifetime and degrading photoelectric conversion performance. Furthermore, the crystallinity of the perovskite is crucial to the photoelectric conversion efficiency of solar cells. Existing research has largely focused on improving the crystallinity of the perovskite, but it cannot simultaneously address the issue of exposed fluorine-doped tin oxide in the first electrode.

[0106] Based on this, this application provides a solar cell with improved photoelectric conversion efficiency and a method for preparing the same, as well as a photovoltaic module, an electrical device, and a power generation device.

[0107] In some embodiments of the first aspect of this application, this application provides a solar cell including a first electrode and a perovskite layer stacked together; the first electrode includes fluorine-doped tin oxide; the fluorine-doped tin oxide includes an FTO crystal phase, the FTO crystal phase including an FTO (110) crystal plane; the perovskite layer includes a perovskite crystal phase, the perovskite crystal phase including a perovskite dominant crystal plane;

[0108] The first electrode includes a first surface away from the perovskite layer, and the perovskite layer includes a second surface away from the first electrode. The region from the first surface to the second surface in the solar cell is referred to as the first structural region.

[0109] Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the dominant perovskite crystal plane to the diffraction peak of the FTO (110) crystal plane is denoted as M1, where M1≥5; wherein, X-rays are injected into the first structural region from the second surface to the first surface.

[0110] Studies have found that if there is an exposed area of ​​the first electrode at the interface between the first electrode and the perovskite layer (e.g., incomplete coverage or poor contact between the perovskite layer and the first electrode, resulting in local exposure of the first electrode), this exposed area is prone to becoming a non-radiative recombination center, where photogenerated carriers (electrons and holes) easily recombine, reducing carrier lifetime and degrading photoelectric conversion performance. The FTO (110) crystal plane is a common crystal plane reference peak in the fluorine-doped tin oxide (FTO) crystal phase. Its intensity is stable and can be used to characterize the relative content of the main FTO crystal phase in the first electrode. The M1 value is negatively correlated with the peak height of the diffraction peak of the FTO (110) crystal plane and positively correlated with the peak height of the dominant perovskite crystal plane. Furthermore, the peak height of the diffraction peak of the FTO (110) crystal plane is related to the degree of exposure in the first electrode. The smaller the degree of exposure, the smaller the peak height of the FTO (110) crystal plane diffraction peak and the larger the M1 value. Furthermore, the dominant crystal facets of perovskites are those that are preferentially exposed or oriented due to favorable energy or growth kinetics. They are key factors connecting the microstructure and macroscopic properties. Increasing the proportion of dominant crystal faces is beneficial to improving the crystal quality of perovskites, thereby improving the macroscopic photoelectric conversion efficiency. The peak height of the diffraction peaks of the dominant crystal facets of perovskites can characterize the crystal quality of perovskites.

[0111] By controlling the peak height ratio (M1) of the diffraction peak of the dominant perovskite crystal plane to that of the FTO (110) crystal plane within the aforementioned range, the dominant perovskite crystal plane can be controlled to have a higher proportion in the perovskite layer. In this case, the crystal quality of the perovskite layer is higher and there are fewer defects, which can reduce non-radiative recombination and is beneficial to carrier transport. At the same time, by controlling M1 within the aforementioned range, from the projection plane in the thickness direction of the perovskite layer from the second surface to the first surface, the exposure degree of FTO in the first electrode can also be controlled to be lower. In this case, it is beneficial to reduce carrier recombination caused by surface defects due to FTO exposure, prolong carrier lifetime and enhance effective carrier collection. Thus, the macroscopic photoelectric conversion efficiency is improved.

[0112] It is understandable that we do not wish to be limited to the aforementioned theories. For example, by controlling the exposure level of FTO in the first electrode to be low, it is also beneficial to reduce the risk of electrode corrosion and interfacial contact, thereby improving the performance reliability of solar cells.

[0113] In this application, the physical meaning of "dominant crystal plane" is: the crystal plane with the dominant orientation in the grain corresponding to the dominant crystal plane, also called the "dominant orientation crystal plane," indicating that the perovskite phase preferentially grows along this crystal plane during the growth process, and the final main exposed crystal plane is also the dominant crystal plane. In this application, unless otherwise specified, the dominant crystal plane of different perovskite phases can be determined as follows: the crystal plane corresponding to the strongest diffraction signal of the corresponding phase in the XRD one-dimensional diffraction pattern or GIWAXS two-dimensional diffraction pattern is determined as the dominant crystal plane. "Perovskite dominant crystal plane" refers to the dominant crystal plane of the perovskite phase.

[0114] In this application, "perovskite phase" refers to the crystal phase of perovskite materials. "FTO phase" refers to the crystal phase of fluorine-doped tin oxide. "FTO (110) plane" refers to the (110) plane present in the crystal phase of fluorine-doped tin oxide, specifically the diagonal tangent that is simultaneously 45° to both the a-axis and b-axis and parallel to the c-axis, with a Miller index of (110). In the XRD pattern, the peak present at a diffraction angle 2θ of 26.58°±0.5° represents the FTO (110) plane. The crystal plane can be analyzed by XRD (including grazing incidence X-ray diffraction, GIWAXS), HR-TEM, etc.

[0115] In this application, the peak height of different diffraction peaks refers to the peak height corresponding to the diffraction peak of a specific crystal plane on the XRD diffraction pattern, which is the net maximum value of the diffraction intensity at the Bragg angle (2θ) position corresponding to the diffraction peak after background subtraction.

[0116] Understandably, the XRD diffraction pattern of the first structural region is obtained by disassembling the solar cell to obtain a component sample consisting of the perovskite layer and the first electrode, and performing XRD testing with the second surface (i.e. the surface of the perovskite layer away from the first electrode) as the X-ray incident surface.

[0117] like Figure 1 As shown, a solar cell 100 according to one embodiment of this application includes a first electrode 120 and a perovskite layer 140 stacked together. The first electrode 120 includes a first surface 1201 away from the perovskite layer 140, and the perovskite layer 140 includes a second surface 1402 away from the first electrode 120. The first surface 1201 and the second surface 1402 constitute a first structural region.

[0118] In some embodiments, M1 can be 5 to 15, and more preferably 5 to 12, such as 5, 6, 8, 10, 12, 14, or 15. In this case, the dominant perovskite crystal plane has a high proportion in the perovskite layer, resulting in high crystal quality and few defects in the perovskite layer. This reduces non-radiative recombination and is beneficial for carrier transport. Simultaneously, the low exposure of FTO in the first electrode helps reduce carrier recombination caused by surface defects due to FTO exposure, extending carrier lifetime and enhancing effective carrier collection. Therefore, the macroscopic photoelectric conversion efficiency is improved.

[0119] In some embodiments, the dominant perovskite crystal plane is the perovskite (100) crystal plane. The perovskite (100) crystal plane has a low defect state density and a high carrier lifetime, which is beneficial for reducing defect density, improving carrier and charge transport efficiency, and thus better improving the photoelectric conversion efficiency of solar cells.

[0120] In this application, the perovskite (100) crystal plane refers to the (100) crystal plane of perovskite material, specifically the low Miller index crystal plane with a Miller index of (100) on the surface orientation of the perovskite crystal phase. This crystal plane is perpendicular to one axis (the a-axis) of the unit cell and parallel to the other two axes. The perovskite (100) crystal plane is one of the most common crystal planes in perovskite materials. In the XRD pattern, the peak present at a diffraction angle 2θ of 13.92°±0.5° represents the perovskite (100) crystal plane.

[0121] In some embodiments, the perovskite crystal phase further includes a perovskite (110) crystal plane; based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite (100) crystal plane to the diffraction peak of the perovskite (110) crystal plane is denoted as M2, where M2≥5 and can be optionally M2≥8.

[0122] The dense atomic arrangement and high compactness of the perovskite (110) crystal facet are beneficial for reducing ion migration and improving reliability. Furthermore, by controlling M2 within the above range, the proportion of the dominant (100) crystal facet in the perovskite crystal phase is high, resulting in high crystal quality and fewer defects in the perovskite layer. This reduces non-radiative recombination and is beneficial for carrier transport. At the same time, it can combine the advantages of the perovskite (110) crystal facet to improve the compactness of the perovskite layer. Thus, it balances carrier transport efficiency, defect density, and ion migration, thereby improving the photoelectric conversion efficiency of the solar cell.

[0123] In this application, the perovskite (110) crystal plane refers to the (110) crystal plane of the perovskite material, specifically the diagonal tangent that forms a 45° angle with both the a-axis and b-axis and is parallel to the c-axis, with a Miller index of (110). In the XRD pattern, the peak present at a diffraction angle 2θ of 19.73°±0.5° represents the perovskite (110) crystal plane.

[0124] In some embodiments of this application, M2 can be 5 to 28, further optionally 8 to 28, and even more preferably 8 to 25, such as 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 22, 24, 25, 26, 28, etc. In this case, the proportion of the dominant crystal plane (100) in the perovskite crystal phase is high, the crystal quality of the perovskite layer is high and there are few defects, which can reduce non-radiative recombination and is conducive to carrier transport. At the same time, the advantages of the perovskite (110) crystal plane can be combined to improve the compactness of the perovskite layer, thereby taking into account the carrier transport efficiency, defect density and ion migration degree, and thus better improving the photoelectric conversion efficiency of the solar cell.

[0125] In some embodiments, fluorine-doped tin oxide further includes an FTO (200) crystal plane; based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (200) crystal plane is denoted as M3, where M3 ≥ 6; optionally, M3 is 6 to 15, and further optionally 6 to 12, such as 6, 8, 10, 12, 14 or 15.

[0126] The FTO (200) crystal plane is also a common crystal plane reference peak in the fluorine-doped tin oxide (FTO) crystal phase. Its intensity is stable and can be used to characterize the relative content of the main FTO crystal phase in the first electrode. By controlling the peak height ratio (M3) of the diffraction peak of the perovskite dominant crystal plane to that of the FTO (200) crystal plane within the aforementioned range, the perovskite dominant crystal plane can be controlled to have a higher proportion in the perovskite layer. At this time, the crystal quality of the perovskite layer is higher and there are fewer defects, which can reduce non-radiative recombination and is beneficial to carrier transport. At the same time, by controlling M3 within the aforementioned range, from the projection plane in the thickness direction of the perovskite layer from the second surface to the first surface, the exposure degree of FTO in the first electrode can also be controlled to be lower. This is beneficial to reduce carrier recombination caused by surface defects due to FTO exposure, prolong carrier lifetime and enhance effective carrier collection. Thus, the macroscopic photoelectric conversion efficiency is improved.

[0127] In this application, the perovskite FTO (200) crystal plane refers to the (200) crystal plane of fluorine-doped tin oxide, specifically the "orthogonal" sectional plane that is perpendicular to the a-axis and parallel to the b and c axes, with a Miller index of (200). In the XRD pattern, the peak present at a diffraction angle 2θ of 37.85°±0.5° represents the FTO (200) crystal plane.

[0128] In some embodiments, the perovskite crystal phase includes a perovskite (100) crystal plane, and the average thickness of the perovskite (100) crystal plane in the normal direction is denoted as D. 100 D 100≥600Å; optionally, 600Å≤D 100 ≤1000Å, such as 600Å, 700Å, 800Å, 900Å, 1000Å, etc.

[0129] The average thickness of the perovskite (100) crystal plane in the normal direction is within the above range. The growth of the perovskite phase in the direction of the perovskite (100) crystal plane is more complete, the corresponding perovskite phase has higher crystallinity, fewer defects, and greater carrier mobility and diffusion length, which is beneficial to reduce nonradiative recombination and thus improve photoelectric conversion efficiency.

[0130] In this application, the term "average thickness of the perovskite (100) crystal plane in the normal direction" refers to the average thickness of crystal domains in coherent diffraction measured along a direction perpendicular to the perovskite (100) crystal plane. Exemplarily, this can be achieved by combining X-ray diffraction (XRD) with the Scherrer equation. The equation is calculated to be: D = Kλ / (βcosθ); where D is the average thickness of the crystal plane in the normal direction (unit: Å), K is the shape factor (0.89 in this application), λ is the X-ray wavelength (unit: nm), β is the full width at half maximum (FWHM) of the diffraction peak (in radians), and θ is the diffraction angle (in radians). In this application, in the XRD pattern, the peak present at a diffraction angle 2θ of 13.92°±0.5° represents the perovskite (100) crystal plane. It can be understood that the perovskite (100) crystal plane is the dominant crystal plane here, and the diffraction peak height corresponding to the (100) crystal plane in the XRD pattern is the largest.

[0131] In some embodiments, the perovskite crystal phase includes a perovskite (110) crystal plane, and the average thickness of the perovskite (110) crystal plane in the normal direction is denoted as D. 110 D 110 ≥ 200Å; optionally, 200Å ≤ D 110 ≤385Å, such as 200Å, 220Å, 240Å, 260Å, 280Å, 300Å, 320Å, 340Å, 350Å, 360Å, 370Å, 380Å, 385Å, etc.

[0132] The average thickness of the perovskite (110) crystal plane in the normal direction is within the above range. The growth of the perovskite phase in the direction of the perovskite (110) crystal plane is more complete, and the corresponding perovskite phase has higher crystallinity, fewer defects, and a more compact arrangement. This can reduce non-radiative recombination and ion migration, improve carrier transport efficiency, and improve the photoelectric conversion efficiency of solar cells.

[0133] In this application, the definition of "average thickness of the perovskite (110) crystal plane in the normal direction" is similar to the definition of "average thickness of the perovskite (100) crystal plane in the normal direction" mentioned above, except that the information of the perovskite (100) crystal plane is replaced with that of the perovskite (110) crystal plane. In this application, in the XRD pattern, the peak present at a diffraction angle 2θ of 19.73°±0.5° represents the perovskite (110) crystal plane.

[0134] In some embodiments, the thickness of the perovskite layer is denoted as H, and the region extending d1 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the first region, where H / 10-20nm≤d1≤H / 10+20nm; the average crystallinity of the perovskite in the first region is less than the average crystallinity of the perovskite in the perovskite layer.

[0135] By controlling the average crystallinity of the first region to be less than that of the perovskite layer, the first region has smaller grains, more grain boundaries and amorphous phases, which can serve as recombination centers, preferentially absorb charge carriers and ions, help to hinder the longitudinal migration of ions, and obtain a high-quality bulk phase, thereby improving the photoelectric conversion efficiency of solar cells.

[0136] In this application, the average crystallinity of a specific region can be expressed by the full width at half maximum (FWHM) or peak height of the diffraction peaks of the dominant crystal plane of the perovskite phase, or by the proportion of all crystallization peaks. For example, when the perovskite phase of the perovskite layer has the perovskite (100) crystal plane as the dominant crystal plane, the average crystallinity can be represented by the FWHM of the diffraction peaks of the perovskite (100) crystal plane. The smaller the FWHM of the diffraction peaks of the perovskite (100) crystal plane, the better the crystallinity and the higher the average crystallinity. Here, the average crystallinity can be represented by the FWHM of the diffraction peaks of the perovskite (100) crystal plane. The FWHM or peak height can be measured by X-ray diffraction (XRD).

[0137] like Figure 2 As shown, a solar cell 100 according to one embodiment of this application includes a perovskite layer 140; the perovskite layer 140 includes a first region 1401, a second surface 1402, and a third surface 1403, with the arrow indicating the light-incident side. The third surface 1403 is the light-incident side surface, located on the side of the perovskite layer facing the first electrode; the first region 1401 is close to the second surface 1402 and includes the second surface 1402, extending from the second surface along the thickness direction toward the interior of the perovskite layer. It is understood that the first region can be a region extending from the second surface along the thickness direction toward the interior of the perovskite layer from H / 10-20nm to H / 10+20nm, for example, a region extending from the second surface along the thickness direction toward the interior of the perovskite layer corresponding to H / 10-20nm, H / 10, or H / 10+20nm.

[0138] In some embodiments, based on the XRD diffraction pattern of the first structural region, the ratio of the full width at half maximum (FWHM) of the diffraction peak of the dominant perovskite crystal plane in the first region to the FWHM of the diffraction peak of the dominant perovskite crystal plane in the perovskite layer is denoted as M4, where M4 is 1:(0.3~0.8), for example 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, or 1:0.8.

[0139] By controlling the ratio of the full width at half maximum (FWHM) of the diffraction peaks of the dominant perovskite crystal plane in the first region to that of the perovskite layer within the aforementioned range, on the one hand, the average crystallinity of the perovskite phase in the first region of the perovskite layer is lower than that in the perovskite layer itself. The first region has smaller grains, more grain boundaries, and amorphous phases, which can serve as recombination centers, preferentially absorbing charge carriers and ions, thus hindering the vertical migration of ions and resulting in a high-quality bulk phase. On the other hand, a moderate difference between the average crystallinity of the perovskite phase in the first region and that in the perovskite layer leads to better overall uniformity of the perovskite layer. This helps reduce performance inhomogeneities caused by local lattice distortion or defect aggregation, promoting the extraction and transport of charge carriers. This, in turn, improves the photoelectric conversion efficiency of the solar cell.

[0140] In some embodiments, the full width at half maximum (FWHM) of the diffraction peaks of the dominant perovskite crystal plane in the perovskite layer is 0.085°~0.131°, for example, 0.085°, 0.09°, 0.1°, 0.11°, 0.12°, 0.13°, 0.131°, etc. In this case, the diffraction peaks of the perovskite (100) crystal plane in the perovskite layer have a smaller FWHM, indicating higher crystallinity of the perovskite phase. This suggests that the perovskite phase has a more regular crystal structure and more ordered atomic arrangement, which helps to reduce grain boundaries and defects in the perovskite layer, reduce the probability of nonradiative recombination of charge carriers, and improve carrier mobility. Simultaneously, controlling the FWHM within the aforementioned range also indicates a more uniform crystal orientation, which is beneficial for reducing scattering and trapping effects of charge carriers during transport, thus improving the overall carrier transport rate. Therefore, the photoelectric conversion efficiency of the solar cell is improved.

[0141] In some embodiments, the full width at half maximum (FWHM) of the diffraction peaks of the dominant perovskite crystal plane of the perovskite layer in the first region is 0.14° to 0.45°, for example, 0.14°, 0.2°, 0.25°, 0.3°, 0.35°, 0.4°, 0.45°, etc.

[0142] In some embodiments, a first additive is present within the perovskite layer; the first additive includes at least one of a fluorinated organic additive and a sulfur-containing organic additive. The fluorinated organic additive and the sulfur-containing organic additive can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of the solar cell by means of strong coordination or hydrogen bonding between fluoride ions / sulfide ions and unsaturated cations on the surface of the perovskite layer.

[0143] In some embodiments, the thickness of the perovskite layer is denoted as H, and the region extending d1 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the first region, where H / 10-20nm≤d1≤H / 10+20nm; a first additive is present in the first region.

[0144] The functional groups (fluoride ions / sulfide ions) of the first additive can preferentially anchor to the perovskite surface through Lewis acid-base coordination, forming strong bonds with unsaturated cations on the perovskite layer surface. This not only passivates surface defects but also constructs a barrier to inhibit ion migration, reducing the degree of ion migration and thus improving the photoelectric conversion efficiency of the solar cell.

[0145] In some embodiments, the fluorinated organic additive includes at least one of pentafluoroiodoethane, heptafluoro-1-iodopropane, 1-iodoperfluorodecane, and perfluorobromobutane. The aforementioned fluorinated passivating agents can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of solar cells by interacting with unsaturated cations on the perovskite substrate surface through strong coordination or hydrogen bonding between fluoride ions and these cations.

[0146] In some embodiments, the sulfur-containing organic additive includes at least one of thionium salts, disulfides, and organic sulfonates. These sulfur-containing organic additives can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of solar cells by interacting with unsaturated cations on the perovskite substrate surface through strong coordination or hydrogen bonding between sulfur ions and these cations.

[0147] In some embodiments, thionium salts include The compound shown in Formula I; wherein R1, R2, and R3 each independently comprise a C1-C4 alkyl group and an aryl group having 6-18 cyclic atoms; X' is a halogen atom. In the perovskite layer, the thionium salt can dissociate into a cation (thionium cation) and can exist as a cation. The structural formula of the thionium cation is... For example, thioonium salts include dimethylphenylethyl mercaptoiodide, whose cation is [(C6H5-CH2-CH2)(CH3)2S]⁺.

[0148] In some embodiments, the disulfide comprises the hydrochloride of CH3HN-R4-SS-R5-NH3CH3, which exists in a cationic form that can be protonated in the perovskite layer; wherein R4 and R5 each independently comprise a C1-C4 alkylene group. Exemplarily, the disulfide comprises 2,2'-dithionidinedimethylbis(N-methylethylamine) dihydrochloride.

[0149] In some embodiments, organic sulfonates include The compound shown in Formula II; R6 and R7 each independently comprise a C1-C4 alkylene group; M comprises at least one sodium ion and a potassium ion. It can dissociate into anion within the perovskite layer. And can exist as anions; for example, organic sulfonates include disodium 1,4-piperazine diethanesulfonate, whose anions can be... .

[0150] In some embodiments, the content of the first additive in the perovskite layer is 0.07 wt% to 0.7 wt%, for example, 0.07 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, etc. Controlling the content of the first additive in the perovskite layer within the above range has two advantages. First, it allows for the interaction of fluoride / sulfur ions with unsaturated cations on the perovskite layer surface through strong coordination or hydrogen bonding, effectively passivating surface defects and reducing ion migration. Second, it reduces the risk of the first additive accumulating and crystallizing at grain boundaries or interfaces, forming a continuous insulating layer, and promotes the lateral transport and vertical extraction of charge carriers between grains. This is beneficial for passivating surface defects while maintaining charge carrier transport efficiency, thereby improving the photoelectric conversion efficiency of the solar cell.

[0151] In this application, the perovskite layer includes a first perovskite material. Unless otherwise specified, "first perovskite material" refers to a type of semiconductor material having a crystal structure similar to that of the natural mineral perovskite (CaTiO3). Specifically, the first perovskite material includes a first cation, a second cation, and an anion, wherein the anion and the second cation together constitute an octahedral structure. The anion is located at the body center of the octahedron, while the second cation is located at the six vertices of the octahedron. The first cation fills the voids in the octahedron to achieve charge balance and maintain crystal structure stability. Adjacent octahedral structures are connected by sharing vertices, thereby achieving a connected crystal lattice structure. The first cation can be denoted as A, and the anion can be denoted as X.

[0152] In some embodiments of this application, the first cation has a relatively large radius and the second cation has a relatively small radius, which is beneficial to obtaining a more stable perovskite crystal phase structure.

[0153] In some embodiments of this application, the perovskite tolerance factor is in the range of 0.85 to 1.0. This is advantageous for obtaining a more stable perovskite crystal phase structure.

[0154] In this application, "perovskite tolerance factor (t)" has a meaning known in the art, and its calculation formula is as follows: , where R A R is the ionic radius of the A-site ion. B R is the ionic radius of the B-site ion. X Let X be the ionic radius of the ion at the X site.

[0155] The first cation in the first perovskite material can be an organic cation, an inorganic cation, or a mixture of organic and inorganic cations; it is understood that the first cation in the first perovskite material can be one or more types. In some embodiments of this application, the first cation includes a monovalent cation, and more specifically, a monovalent cation. The second cation in the first perovskite material can be an organic cation, an inorganic cation, or a mixture of organic and inorganic cations; it is understood that the second cation in the first perovskite material can be one or more types. In some embodiments of this application, the second cation includes a divalent cation, and more specifically, a divalent cation. In some embodiments of this application, the second cation includes a combination of a monovalent cation (denoted as C) and a trivalent cation (denoted as D).

[0156] In some embodiments of this application, the second cation includes one or more of a divalent cation (denoted as B), a monovalent cation (denoted as C), and a trivalent cation (denoted as D). In some embodiments, the material of the perovskite layer includes a perovskite-type metal halide with the chemical formula ABX3 or A2CDX6; wherein A is a monovalent cation, B is a divalent metal cation, C is a monovalent metal cation, D is a trivalent metal cation, and X is a monovalent anion.

[0157] Understandably, "pseudohalogens," also known as halogen-like substances, refer to atomic groups composed of two or more elements that, as a whole, possess chemical properties similar to halogens. Anionic pseudohalogens can be called pseudohalogen anions. Non-limiting examples of pseudohalogens may include one or more of thiocyano (SCN), oxocyano (OCN), etc. Non-limiting examples of pseudohalogen anions may include SCN. - OCN - One or more of the following. It is understandable that pseudohalogens present in first perovskite materials can act as X-site ions.

[0158] Without limitation, in perovskite-type metal halides, A can be a monovalent inorganic cation, a monovalent organic cation, or a mixed cation of monovalent organic and monovalent inorganic cations.

[0159] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, A is a monovalent inorganic cation; optionally, A includes Li. + Na + K + 、Rb + and Cs + One or more of them.

[0160] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, A is a monovalent organic cation; optionally, A includes at least one selected from methylamino, ethylamino, propylamino, butylamino, pentamino, hexamino, formamidinyl, and imidazolyl.

[0161] Without limitation, the A in perovskite materials or perovskite-type metal halides may include Cs. + K + 、Rb + Li + One or more of monovalent organic cations, etc.

[0162] Non-limiting examples of monovalent organic cations include (NR) 31 R 32 R 33 R 34 ) + 、(R 31 R 32 N=CR 33 R 34 ) + 、(R 31 R 32 NC(R 35 )=NR 33 R 34 ) + or (R) 31 R 32 NC(NR 35 R 36 )=R 33 R 34 ) + , where R 31 R 32 R 33 R 34 R 35 and R 36 Each is independently selected from H and C. 1-20 Alkyl, aryl, substituted C 1-20 Alkyl or substituted aryl; wherein, C1-20 Alkyl and substituted C 1-20 The "C" in alkyl 1-20 Each alkyl group can be independently selected as C. 1-15 Alkyl, further optionally C 1-10 Alkyl, and further optionally C 1-8 Alkyl, and further optionally C 1-6 Alkyl, and further optionally C 1-4 Alkyl, and further optionally C 1-3 Alkyl, and further optionally methyl. The "aryl" in aryl and substituted aryl groups can each independently be C10. 6-20 Aryl, further optionally C 6-12 Aryl, and further alternatively C 6-10 Aryl, further optionally phenyl or naphthyl, and further optionally phenyl. Substituted C 1-20 In alkyl and substituted aryl groups, each substituent is independently C1. 1-10 Hydrocarbon group, further optionally C 1-6 Alkyl or C 6-10 Aryl, and may further be methyl or phenyl.

[0163] Non-limiting examples of monovalent organic cations include CH3NH3 + (Methylamine, MA) + ), NH2CH=NH2 + (Formamidin, can be written as FA) + ), dimethylamine cation, ethylamine cation, propylamine cation, butylamine cation, pentamine cation, hexamine cation, imidazole cation.

[0164] In some embodiments of this application, in the perovskite-type metal halide, A includes a monovalent organic cation and Cs. + One or more of them.

[0165] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, B includes divalent cations of one or more of the following elements: lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium.

[0166] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, C represents a monovalent inorganic cation; optionally, C includes Cs. + Ag + K + and Ru + One or more of the following.

[0167] In some embodiments of this application, D represents a trivalent metal cation; optionally, D includes Bi.3+ Ni 3+ Fe 3+ Sb 3+ In 3+ and Cu 3+ One or more of them, and further optionally, D includes In 3+ Bi 3+ Sb 3+ One or more of them.

[0168] In some embodiments of this application, the molar percentage of iodine anions in the monovalent anions of the perovskite material is 0 to 1.0.

[0169] In some embodiments of this application, the molar percentage of bromide anions in the monovalent anions of perovskite materials is 0 to 1.0.

[0170] In this application, unless otherwise specified, the term "aryl" refers to an aromatic hydrocarbon group derived from an aromatic cyclic hydrocarbon compound by losing one hydrogen atom, that is, forming a monovalent linking site directly on the ring. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl; for polycyclic rings, at least one is an aromatic ring system. For example, "C6- 10 "Aryl" refers to an aryl group containing 6 to 10 carbon atoms. Each time it appears, it can be independently C6 aryl, C8 aryl, C9 aryl, or C6 aryl. 10 Aryl. For example, "C6- 20 "Aryl" refers to an aryl group containing 6 to 20 carbon atoms. Each time it appears, it can be independently, but is not limited to, C6 aryl (such as phenyl), C8 aryl (such as benzocyclobutenyl), C9 aryl (such as indenyl), C6 aryl, C8 aryl, C9 ... 10 Aryl (such as naphthyl), C 12 Aryl (such as acenaphthene, biphenyl), C 13 Aryl (such as fluorene), C 14 Aryl (such as anthracene, phenanthrene), C 18 Aryl (such as phenylene) or C 20 Aryl groups (such as dinaphthalene-based phenyl groups). Examples of suitable aromatic cyclic hydrocarbons that can be derived to form aryl groups include, but are not limited to: benzene, benzocyclobutene, biphenyl, indene, naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, triphenylene, dinaphthalene-based phenyl groups and their derivatives.

[0171] Without limitation, in perovskite-type metal halides, B can be an inorganic cation.

[0172] In some embodiments of this application, in the perovskite-type metal halide, B includes a divalent cation; optionally, B includes a divalent cation of one or more of the following elements: lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, europium, etc.

[0173] Without limitation, B in perovskite-type metal halides may include Pb. 2+ Sn 2+ Fe 2+ Mn 2+ Ni 2+ 、Ge 2+ Co 2+ and Sb 2+ One or more of them.

[0174] In perovskite-type metal halides, X can be an inorganic anion, an organic anion, or a mixture of organic and inorganic anions.

[0175] In some embodiments of this application, X in the perovskite-type metal halide is a halide anion; optionally, X includes F. - Cl - ,Br - and I - One or more of them, and optionally, X includes Cl - ,Br - and I - One or more of the following. In some embodiments, X in the perovskite metal halide can be I. - ,Br - and Cl - One or more of them.

[0176] Without limitation, X in perovskite-type metal halides may include I. - ,Br - One or two of them. X can be I. - ,Br - Or a combination thereof. In some embodiments, X is I. - .

[0177] Non-limitingly, in perovskite-type metal halides, C can be an inorganic cation, an organic cation, or a mixed organic-inorganic cation. In some embodiments of this application, C is a monovalent inorganic cation; optionally, C includes Cs. + Ag + K + and Ru + One or more of the following. In some embodiments of this application, C can be silver ions (Ag). + ).

[0178] In a non-limiting sense, in perovskite metal halides, D can be an inorganic cation, an organic cation, or a mixed organic-inorganic cation.

[0179] In some embodiments of this application, D is a trivalent metal cation; optionally, D includes Bi. 3+ Ni 3+ Fe 3+ Sb 3+ In 3+ , and Cu 3+ One or more of them, and further optionally, D includes In 3+ Bi 3+ Sb 3+ One or more of these. In some embodiments, D is a bismuth cation (Bi). 3+ ), antimony cation (Sb) 3+ ) and indium cation (In 3+ At least one of the following.

[0180] It is understandable that the first perovskite material of the aforementioned perovskite layer can be selected from Cs. x1 FA 1-x1 PbX3, Cs x1 MA 1-x1 PbX3, Cs m FA n MA 1-m-n PbX3, CsPbX3, MAPbX3, FAPbX3, Cs x1 FA 1-x1 Pb x2 Sn 1-x2 X3, Cs x1 FA 1-x1 Pb x2 Sn 1-x2 X3, Cs m FA n MA 1-m-n Pb x2 Sn 1-x2 X3, CsPb x2 Sn 1-x2 X3, MAPb x2 Sn 1-x2 X3 and FAPb x2 Sn 1-x2 One or more of X3, where 0 < x1 < 1, 0 < x2 < 1, 0 < m < 1, and 0 < n < 1.

[0181] In some embodiments, the perovskite layer comprises a first perovskite material, the first perovskite material comprising a monovalent cation; the monovalent cation comprises a formamidinyl group and Cs. + At least one of the following; with formamidinyl and Cs + Using the total amount of substance as a benchmark, Cs + The molar percentage is 0-80%.

[0182] Formamidinyl groups possess excellent light absorption and carrier transport properties, which are beneficial for improving photoelectric conversion efficiency. Furthermore, the small radius of Cs⁺, when introduced into the aforementioned amounts, promotes lattice contraction, reduces strain gradient, and improves crystal structure uniformity. Therefore, these monovalent cations can enhance carrier extraction efficiency and improve crystal structure uniformity, thereby improving the photoelectric conversion efficiency of solar cells.

[0183] In some embodiments, the perovskite layer includes a first perovskite material, which includes anions; the anions include at least one of iodide ions and bromide ions; and the molar percentage of bromide ions is 0 to 27% based on the total amount of iodide ions and bromide ions.

[0184] Iodide ions have a large radius, which can expand the crystal lattice and help adjust the band gap. They also promote the formation of perovskite materials with symmetrical crystal phase structures, reducing local strain and defect density, and lowering the resistivity of perovskite materials, thus improving the photoelectric conversion efficiency of solar cells. Bromine ions, on the other hand, have a smaller radius. Introducing bromide ions in the aforementioned amounts helps to shrink the crystal lattice, reduce the strain gradient, and improve crystal structure uniformity, further enhancing the photoelectric conversion efficiency of solar cells.

[0185] In some embodiments of this application, the perovskite layer includes a first perovskite material, which includes FA. 1-x1 Cs x1 PbBr x2 I 3-x2 Where x1 is 0~0.8, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8; and x2 is 0~0.8, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8. Formamidinyl groups possess excellent light absorption and carrier transport characteristics. Iodide ions have a large radius, which can cause lattice expansion, facilitating bandgap adjustment. Simultaneously, iodide ions are beneficial for forming perovskite materials with symmetrical crystal phase structures, reducing local strain and defect density, and also helping to lower the resistivity of perovskite materials, thus improving photoelectric conversion efficiency. Meanwhile, Cs⁺ and bromide ions have small radii, which facilitate lattice contraction, reduce strain gradient, improve crystal structure uniformity, and further improve the photoelectric conversion efficiency of solar cells.

[0186] In some embodiments of this application, the thickness of the perovskite layer can be selected as a conventional thickness in the art, such as 200 nm to 1500 nm. For example, the thickness of the perovskite layer can be 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, etc., or a range consisting of any two of the above values, such as 200 nm to 300 nm, 300 nm to 500 nm, 400 nm to 800 nm, 600 nm to 1000 nm, 200 nm to 1500 nm, etc.

[0187] In some embodiments of this application, the area of ​​the perovskite layer is greater than or equal to 0.07 m² in the direction perpendicular to the thickness of the perovskite layer. 2 This will help improve the efficiency of solar cells and reduce costs.

[0188] In some embodiments of this application, the solar cell is a multi-junction solar cell, which includes a first cell unit and a light-absorbing layer (which may be referred to as a first light-absorbing layer). The first light-absorbing layer may include the aforementioned perovskite layer.

[0189] In this application, unless otherwise specified, a "multi-junction solar cell" refers to a solar cell in which two or more cell cells made of semiconductor active materials with different band gaps are stacked together in series optically and / or electrically. Multi-junction solar cells can broaden the absorption spectrum of solar cells, maximizing the conversion of light energy into electrical energy, and also help reduce thermal relaxation losses. Multi-junction solar cell design is an important way to overcome the Shockley-Queisser limit efficiency of single-junction solar cells. A multi-junction solar cell includes at least two cell cells, each cell cell including at least one light-absorbing layer, and each light-absorbing layer has a different band gap.

[0190] It is understandable that a "cell" in a multi-junction solar cell includes at least a light-absorbing layer. The light-absorbing layers in different cells can provide different band gaps.

[0191] In this application, unless otherwise specified, "battery cell" and "battery section" have the same meaning and can be used interchangeably.

[0192] In this application, unless otherwise specified, "light-absorbing layer" and "light-absorbing layer" have the same meaning and can be used interchangeably.

[0193] In this application, unless otherwise specified, "band gap" has a commonly known meaning in the art and can be analyzed, compared, and confirmed using conventional methods within the art. Without limitation, the band gap of a material can be determined by its absorption or emission spectra; commonly used optical methods include ultraviolet-visible absorption spectroscopy, photoluminescence spectroscopy, and Raman spectroscopy.

[0194] When solar cells are multi-junction solar cells, they are beneficial for improving the utilization rate of incident light, while also possessing the aforementioned advantages of high photoelectric conversion efficiency and high device stability. Multi-junction solar cells can be monolithic integrated tandem solar cells or mechanically tandem solar cells, offering flexibility in form and a wide range of applications.

[0195] In some embodiments of this application, the first light-absorbing layer is the aforementioned perovskite layer.

[0196] The aforementioned perovskite layer can be incorporated into multi-junction solar cells to improve the photoelectric conversion efficiency and device stability of multi-junction solar cells.

[0197] In some embodiments of this application, the multijunction solar cell further includes a second cell stacked with the first cell cell; the second cell cell and the first cell cell are connected by an interconnect layer, or the second cell cell and the first cell cell are isolated by an insulating layer; the second cell cell includes a light-absorbing layer (which may be referred to as the second light-absorbing layer), and the second light-absorbing layer and the first light-absorbing layer have different band gaps.

[0198] In some embodiments of this application, the interconnect layer includes a carrier recombination layer or a tunneling layer. In some embodiments, the interconnect layer can be a carrier recombination layer or a tunneling layer.

[0199] In some embodiments of this application, the interconnect layer includes a carrier recombination layer.

[0200] In some embodiments of this application, the interconnect layer includes a tunneling layer.

[0201] In some embodiments of this application, the second light-absorbing layer and the perovskite layer have different band gaps. Thus, by providing multiple light-absorbing layers with different band gaps, the multi-junction solar cell can effectively absorb light of different wavelengths, broadening the spectral range of absorbed light and improving the photoelectric conversion efficiency of the multi-junction solar cell.

[0202] In some embodiments, the multijunction solar cell is a tandem solar cell.

[0203] In some embodiments of this application, the multi-junction solar cell further includes a second cell stacked with the first cell cell; the second cell cell and the first cell cell are connected by an interconnect layer, or the second cell cell and the first cell cell are isolated by an insulating layer; the second cell cell includes a light-absorbing layer (i.e., a second light-absorbing layer), and the second light-absorbing layer and the perovskite layer have different band gaps. Thus, by providing multiple light-absorbing layers with different band gaps, the multi-junction solar cell can effectively absorb light of different wavelengths, broadening the spectral range of light absorbed by the multi-junction solar cell and improving its photoelectric conversion efficiency.

[0204] In some embodiments of this application, the light-absorbing layer (i.e., the second light-absorbing layer) in the second battery cell includes a semiconductor active material (which may be referred to as the second semiconductor active material). The second semiconductor active material includes one or more of the following: a second perovskite material, a silicon-containing semiconductor material, a copper zinc tin sulfide, a copper zinc tin selenide, a copper zinc tin selenide sulfide, a copper indium gallium selenide, a copper indium gallium diselenide, a copper indium selenide, cadmium telluride, gallium arsenide, and organic active materials.

[0205] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0206] In some embodiments of this application, a carrier recombination layer or tunneling layer is provided between battery cells connected in series.

[0207] In this application, unless otherwise stated, the "carrier recombination layer" is a structural layer in which electrons and holes transported from two different battery cells recombine, thereby enabling the two battery cells to be connected in series.

[0208] In some embodiments of this application, a carrier recombination layer is provided between the first battery cell and the second battery cell.

[0209] In some embodiments of this application, interconnection structures are provided between the battery cells connected in series, which can provide tunneling junctions (also known as tunneling layers) to achieve ohmic connection and electrical series connection between different battery cells, while maintaining optical transparency so that photons can pass smoothly through the previous battery cell to the next battery cell.

[0210] In some embodiments of this application, an interconnection structure is provided between the first battery cell and the second battery cell.

[0211] In some embodiments of this application, a tunnel junction may be formed between the first battery cell and the second battery cell.

[0212] In some embodiments of this application, the charge carrier recombination layer is a structural layer in which electrons transported from the first battery cell and holes transported from the second battery cell recombine, or in which holes transported from the first battery cell and electrons transported from the second battery cell recombine, thereby connecting the first battery cell and the second battery cell in series.

[0213] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together. The interconnect layer is located between the perovskite layer and the second light-absorbing layer. The first electrode is located on the side of the perovskite layer facing away from the interconnect layer, and the second electrode is located on the side of the second light-absorbing layer facing away from the interconnect layer. Thus, two cell units in the multi-junction solar cell are connected through the interconnect layer to achieve current matching between the two cell units. This results in a relatively smaller size, the ability to absorb light of different wavelengths, a wider absorption spectrum range for the multi-junction solar cell, and an improved photoelectric conversion efficiency. In some embodiments, a hole transport layer is provided between the first electrode and the perovskite layer.

[0214] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, insulating layer, and fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is located on the side of the insulating layer facing the perovskite layer, and the fourth electrode is located on the side of the insulating layer facing the second light-absorbing layer. The first electrode is located on the side of the perovskite layer away from the third electrode, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode. Thus, the multi-junction solar cell forms a mechanically stacked cell. The insulating layer isolates the two cell units, preventing direct conduction of charge carriers and eliminating the need for current matching. Furthermore, each cell has its own separate positive and negative electrodes for current extraction, allowing for flexible circuit adjustments. In some embodiments of this application, a hole transport layer is provided between the first electrode and the perovskite layer.

[0215] In this application, unless otherwise specified, a multi-junction solar cell with two battery cells may also be referred to as a "tandem solar cell". A tandem solar cell may be a two-terminal structure or a four-terminal structure.

[0216] In some embodiments of this application, the tandem solar cell has a two-end structure. In this case, two cell units are directly connected in series through a tunneling layer or a carrier recombination layer. The tandem solar cell has only two output electrodes, one positive and the other negative, and the current between them is consistent. This type of tandem solar cell can also be called a monolithic integrated tandem cell, which refers to cell units stacked along the thickness direction that are electrically connected in series between a pair of electrode layers. Different cell units are connected through a carrier recombination layer or a tunneling layer to achieve current matching between adjacent cell units, so that adjacent cell units form an integrated structure of electrical and optical series connection.

[0217] In some embodiments of this application, the tandem solar cell includes a first electrode, a first light-absorbing layer, a carrier recombination layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer and the second light-absorbing layer are respectively disposed on both sides of the carrier recombination layer. The first electrode is located on the side of the first light-absorbing layer away from the carrier recombination layer, and the second electrode is located on the side of the second light-absorbing layer away from the carrier recombination layer.

[0218] In some embodiments of this application, the tandem solar cell includes a first electrode, a first light-absorbing layer, a tunneling layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer and the second light-absorbing layer are respectively disposed on both sides of the tunneling layer. The first electrode is located on the side of the first light-absorbing layer away from the tunneling layer, and the second electrode is located on the side of the second light-absorbing layer away from the tunneling layer.

[0219] In some embodiments of this application, the tandem solar cell has a four-terminal structure. In this case, the cell units are electrically independent and operate independently, with coupling between the cell units only through optical means; no carrier recombination layer or tunneling layer is provided between the cell units. Each cell unit has its own pair of electrodes (positive and negative), and the entire tandem solar cell has four electrical output terminals, corresponding to the four electrodes. Two cell units are isolated in the stacking direction by an insulating layer to prevent short circuits between the two cell units.

[0220] In some embodiments of this application, the solar cell satisfies one or more of the following features:

[0221] (a1) The perovskite layer is contained in the inverse or formal structure of the solar cell;

[0222] (a2) The solar cell includes a first transport layer and a second transport layer, and a perovskite layer is stacked between the first transport layer and the second transport layer; wherein, one of the first transport layer and the second transport layer is a hole transport layer and the other is an electron transport layer.

[0223] The aforementioned embodiments can be universally applied to solar cells with conventional or inverted structures, thereby improving photoelectric conversion efficiency and device stability. Furthermore, the aforementioned advantages of the perovskite layer are independent of the positional relationship between the hole transport layer and the electron transport layer stacked with it, allowing these advantages to be utilized in devices with different structures.

[0224] In some implementations, the bandgap of the perovskite layer (i.e., the first light-absorbing layer) is Eg2, where 1.65 eV ≤ Eg2 ≤ 2.2 eV; the bandgap of the second light-absorbing layer is Eg1, where 1.1 eV ≤ Eg1 ≤ 1.6 eV. This bandgap configuration of the perovskite layer and the second light-absorbing layer effectively absorbs both short-wavelength and long-wavelength light, improving the photoelectric conversion efficiency of the multi-junction solar cell. In this implementation, the cell unit corresponding to the second light-absorbing layer is a narrow-bandgap solar cell, and the cell unit corresponding to the perovskite layer is a wide-bandgap solar cell.

[0225] In some embodiments, the second light-absorbing layer comprises a layer of compounds such as: a second perovskite material, crystalline silicon, an organic active material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, gallium arsenide, or cadmium telluride. These materials can absorb light of different wavelengths with the perovskite layer, thereby broadening the spectral range of light absorption in the multi-junction solar cell and improving its photoelectric conversion efficiency. In some embodiments of this application, the definition of the second perovskite material is the same as that of the first perovskite material, but the composition differs to obtain a second light-absorbing layer with a different bandgap, used to absorb light of different wavelengths with the perovskite layer, broadening the absorption spectral range of the multi-junction solar cell and improving its photoelectric conversion efficiency. Exemplarily, the second light-absorbing layer comprises a second perovskite material, thereby obtaining a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises a crystalline silicon material, thereby obtaining a perovskite-crystalline silicon multi-junction solar cell.

[0226] Organic active materials are composed of blends of electron donor and electron acceptor materials. Common electron donor materials include poly(3-hexylthiophene) (P3HT), wide-bandgap polymer donor PM6, and high-efficiency polymer donor D18, etc. Common electron acceptor materials include fullerene acceptors (such as PC). 61 BM, PC 71 BM, etc.), and non-fullerene acceptors (such as Y6 series materials, indendrothiophene derivatives, BTP series, etc.). Exemplary organic active materials include PM6:Y6 and P3HT:PC. 61 One of BM, D18:BTP-eC9, etc. can be used to obtain multiple types.

[0227] Silicon-containing semiconductor materials include, but are not limited to, crystalline silicon materials or amorphous silicon materials. Crystalline silicon materials can include monocrystalline silicon or polycrystalline silicon.

[0228] In some embodiments, a multi-junction solar cell includes a first electrode and a second electrode, with a first light-absorbing layer and a second light-absorbing layer both located between the first electrode and the second electrode, the first light-absorbing layer being closer to the first electrode and the second light-absorbing layer being closer to the second electrode.

[0229] In some implementations, the first electrode in a multi-junction solar cell is a transparent electrode. This allows light to enter the multi-junction solar cell from the first electrode. Furthermore, the band gap of the second light-absorbing layer is Eg1, 1.1 eV ≤ Eg1 ≤ 1.6 eV; the band gap of the perovskite layer is Eg2, 1.65 eV ≤ Eg2 ≤ 2.2 eV. Thus, light entering from the first electrode first passes through the perovskite layer, where it absorbs short-wavelength light (such as ultraviolet to visible light), and then enters the second light-absorbing layer, where it absorbs longer-wavelength light (such as near-infrared light). This allows for greater utilization of different wavelengths of light, improving the photoelectric conversion efficiency of the multi-junction solar cell. Furthermore, the perovskite layer, acting as the top light-absorbing layer, absorbs ultraviolet-visible light, protecting the second light-absorbing layer, which acts as the bottom light-absorbing layer.

[0230] In other embodiments, the bandgap of the second light-absorbing layer is Eg3, where 1.65 eV ≤ Eg3 ≤ 2.2 eV; and the bandgap of the perovskite layer is Eg4, where 1.1 eV ≤ Eg4 ≤ 1.6 eV. Thus, the bandgap settings of the second light-absorbing layer and the perovskite layer can absorb short-wavelength and long-wavelength light respectively, improving the photoelectric conversion efficiency of the multi-junction solar cell. In this embodiment, the cell unit corresponding to the second light-absorbing layer is a wide-bandgap solar cell, and the cell unit corresponding to the perovskite layer is a narrow-bandgap solar cell.

[0231] In other embodiments, the second light-absorbing layer comprises a third perovskite material. Thus, the resulting multi-junction solar cell is a perovskite-perovskite multi-junction solar cell. In some embodiments of this application, the third perovskite material is defined as the same type as the first perovskite material described above, but with a different composition to obtain a second light-absorbing layer with a different bandgap. This layer is used to absorb light of different wavelengths with the perovskite layer, broadening the absorption spectrum range of the multi-junction solar cell and improving its photoelectric conversion efficiency. Exemplarily, the third perovskite material includes APbI. z Br 3-z The material shown is defined as above, where 0 < z < 3.

[0232] In other embodiments, the second electrode in a multi-junction solar cell is a transparent electrode. This allows light to enter the multi-junction solar cell through the second electrode. Furthermore, the band gap of the second light-absorbing layer is Eg3, 1.65 eV ≤ Eg3 ≤ 2.2 eV; the band gap of the perovskite layer is Eg4, 1.1 eV ≤ Eg4 ≤ 1.6 eV. Thus, light entering from the second electrode first passes through the second light-absorbing layer, which absorbs short-wavelength light (such as ultraviolet to visible light), and then enters the perovskite layer, where it absorbs longer-wavelength light (such as near-infrared light). This allows for greater utilization of different wavelengths of light, improving the photoelectric conversion efficiency of the multi-junction solar cell. Furthermore, the second light-absorbing layer, acting as the top cell's light-absorbing layer, absorbs ultraviolet-visible light, protecting the perovskite layer as the bottom cell's light-absorbing layer.

[0233] In some embodiments, a multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together, with the interconnect layer located between the perovskite layer and the second light-absorbing layer. The interconnect layer may include a carrier recombination layer or a tunneling layer. Thus, the multi-junction solar cell forms a monolithic integrated tandem cell, with two cell units connected by an interconnect layer (e.g., through a carrier recombination layer or a tunneling layer) to achieve current matching between the two cell units. It has a relatively smaller size, can absorb light of different wavelengths, broadens the absorption spectrum range of the multi-junction solar cell, and improves the photoelectric conversion efficiency of the multi-junction solar cell.

[0234] In some embodiments, a multijunction solar cell includes a first electrode, a perovskite layer, a tunneling layer, a second light-absorbing layer, and a second electrode stacked together, with the tunneling layer located between the perovskite layer and the second light-absorbing layer.

[0235] In some implementations, a multijunction solar cell includes a first transport layer, a second transport layer, a third transport layer, and a fourth transport layer.

[0236] In this application, the first transport layer, the second transport layer, the third transport layer, and the fourth transport layer are used to transport the first charge carrier, the second charge carrier, the third charge carrier, and the fourth charge carrier, respectively. One of the first charge carrier and the second charge carrier is an electron and the other is a hole. One of the third charge carrier and the fourth charge carrier is an electron and the other is a hole.

[0237] In some embodiments, a multi-junction solar cell includes a first electrode, optionally a first transport layer, a perovskite layer, optionally a second transport layer, a carrier recombination layer or a tunneling layer, optionally a third transport layer, a second light-absorbing layer, optionally a fourth transport layer, and a second electrode, all stacked together. The multi-junction solar cell includes at least one of the first and second transport layers, and also includes a hole transport layer. Further, when the first to fourth carriers are present, the first and third transport layers are identical and selected from either an electron transport layer or a hole transport layer, and the second and fourth transport layers are identical and selected from either an electron transport layer or a hole transport layer. Thus, a first electrode, optionally a first transport layer, a perovskite layer, and optionally a second transport layer form a first battery cell; a third transport layer, a second light-absorbing layer, optionally a fourth transport layer, and a second electrode form a second battery cell. A carrier recombination layer is used to recombine and annihilate electrons generated from the perovskite layer and holes generated from the second light-absorbing layer that are transported towards the carrier recombination layer, thereby achieving low-ohmic tunnel recombination between the first battery cell containing the perovskite layer and the second battery cell containing the second light-absorbing layer, ensuring connectivity between the two battery cells. A tunneling layer is located between the two battery cells, and its main function is to achieve efficient transport of electrons and holes. Through the tunneling effect, the tunneling layer allows electrons and holes to be transported from the bottom battery to the top battery, thereby reducing energy loss due to electron thermal relaxation and improving the photoelectric conversion efficiency of the battery. Exemplarily, the second light-absorbing layer includes a second perovskite material, thus obtaining a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer includes crystalline silicon, thus obtaining a perovskite-crystalline silicon multi-junction solar cell.

[0238] In some embodiments of this application, the multi-junction solar cell may include all four transport layers simultaneously, or only one or more of them; this is not limited here. The transport layer helps to extract and transport electrons or holes generated by the perovskite layer or the second light-absorbing layer, enhancing the extraction and transport effect of electrons and holes and improving the performance of the multi-junction solar cell. The corresponding electron transport materials and hole transport materials are selected as defined below; the corresponding electron transport materials and hole transport materials for the first and second cell units may be the same or different.

[0239] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, a carrier recombination layer or a tunneling layer, optionally a hole transport layer, a second light absorption layer, optionally an electron transport layer, and a second electrode, all stacked together.

[0240] In this application, the carrier recombination layer comprises one or more of metallic materials, transparent conductive oxides, and carbon materials. Further, the transparent conductive oxide layer comprises, but is not limited to, one or more of FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), IZO (indium zinc oxide), IWO (tungsten-doped indium oxide), IGZO (indium gallium zinc oxide), and ATO (antimony-doped tin oxide). Further, the metallic materials include, but are not limited to, one or more of gold, copper, silver, platinum, aluminum, and iron. Further, the carbon materials include one or more of graphite, graphene, and carbon nanotubes.

[0241] In some embodiments of this application, the thickness of the carrier recombination layer is 0.1 nm to 200 nm. For example, it can be 0.1 nm, 0.8 nm, 1 nm, 2 nm, 10 nm, 30 nm, 50 nm, 90 nm, 100 nm, 130 nm, 150 nm, 160 nm, 200 nm, or within the range of any two of the above values ​​as endpoints.

[0242] In some implementations, the components of the tunneling layer include, but are not limited to, PEDOT, transparent metal oxides, etc.

[0243] In other embodiments, a multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, insulating layer, and fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is positioned on the side of the insulating layer facing the perovskite layer, and the fourth electrode is positioned on the side of the insulating layer facing the second light-absorbing layer. In this way, the multi-junction solar cell forms a mechanically stacked cell. The insulating layer isolates the two cell units, preventing direct parallel connection of charge carriers and eliminating the need for current matching. Furthermore, each cell unit has its own independent positive and negative electrodes for current extraction, allowing for flexible circuit adjustments.

[0244] In this application, the fifth, sixth, seventh, and eighth transport layers are used to transport the fifth, sixth, seventh, and eighth charge carriers, respectively. One of the fifth and sixth charge carriers is an electron, and the other is a hole. One of the seventh and eighth charge carriers is an electron, and the other is a hole.

[0245] In some embodiments, a multi-junction solar cell includes a first electrode, optionally a fifth transport layer, a perovskite layer, optionally a sixth transport layer, a third electrode, an insulating layer, a fourth electrode, optionally a seventh transport layer, a second light-absorbing layer, optionally an eighth transport layer, and a second electrode stacked together. The fifth transport layer is selected from either a hole transport layer or an electron transport layer; the sixth transport layer is selected from either a hole transport layer or an electron transport layer different from the fifth transport layer; the seventh transport layer is selected from either a hole transport layer or an electron transport layer; and the eighth transport layer is selected from either a hole transport layer or an electron transport layer different from the seventh transport layer. The corresponding electron transport materials and hole transport materials are selected as defined below. Thus, a first electrode, optionally a fifth transport layer, a perovskite layer, optionally a sixth transport layer, and a third electrode form a first battery cell; a fourth electrode, optionally a seventh transport layer, a second light-absorbing layer, optionally an eighth transport layer, and a second electrode form a second battery cell. The first and second battery cells are electrically isolated by an insulating layer. Each battery cell has two electrodes, for a total of four electrodes. The circuits of the two battery cells are independent of each other, forming a four-terminal multi-junction solar cell. This allows for adjustment of the current in the multi-junction solar cell. For example, the second light-absorbing layer comprises a second perovskite material, resulting in a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises crystalline silicon, resulting in a perovskite-crystalline silicon multi-junction solar cell.

[0246] Furthermore, since the third and fourth electrodes are located in the middle of the multi-junction solar cell, in order to further increase the light energy utilization of the multi-junction solar cell and enable the remaining light after absorption by one cell to enter the next cell, the third and fourth electrodes can be set as light-transmitting electrodes, and the materials can be selected from one or more of the above-mentioned transparent conductive oxides.

[0247] In some embodiments, the material of the insulating layer includes, but is not limited to, glass or an insulating adhesive. Further, the glass is transparent glass; further, the insulating adhesive is a transparent adhesive.

[0248] In some embodiments, the multi-junction solar cell may also include multi-junction solar cells composed of 3, 4, or 5 cells, such as 3-junction solar cells, 4-junction solar cells, 5-junction solar cells, etc., and may be mechanically stacked cells, monolithically integrated stacked cells, or hybrid stacked cells composed of both, without limitation here.

[0249] It is understood that the hole transport layer includes hole transport materials. Without limitation, the hole transport materials in the hole transport layer may include, but are not limited to, one or more of the following materials and their derivatives: hole transport organic materials and hole transport inorganic materials.

[0250] In some embodiments of this application, the hole transport material includes hole transport organics. Without limitation, the hole transport organics may include, but are not limited to, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly-3-hexylthiophene, methoxytriphenylamine-fluoroformamidinium, triphenylamine with a triphenylene core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-aniline)carbazole-spirobifluorene, polythiophene, carbazole-based monomers or polymers (such as [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid... The hole transport material comprises one or more of the following: [4-(9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphonic acid (Br-4PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dibromo-9H-carbazole-9-yl)ethyl]phosphonic acid (Br-2PACz), triphenylamine monomers or polymers, aromatic monomers or polymers, etc. In some embodiments of this application, the hole transport material includes hole transport inorganic substances. Non-limitingly, the hole transport inorganic material may include, but is not limited to, one or more of metal oxides (which may be referred to as the first metal oxide), cuprous iodide and cuprous thiocyanate, molybdenum sulfide, etc.; wherein, the metal oxide in the hole transport material may include, but is not limited to, one or more of nickel oxide, molybdenum oxide, cuprous oxide, vanadium oxide, and tungsten oxide. As a non-limiting example, in the hole transport material, the metal element in the first metal oxide may include one or more of nickel (Ni), molybdenum (Mo), copper (Cu), vanadium (V), and tungsten (W).

[0251] It is understood that the electron transport layer includes electron transport materials. Without limitation, the electron transport materials in the electron transport layer may include, but are not limited to, one or more of the following materials and their derivatives, impurities, and passivated materials: fullerenes and their derivatives, imide compounds, metal oxides, metal sulfides, metal fluorides, cyano-containing polyphenylacetylene, boron-containing polymers, copper bath, red phenanthroline, hydroxyquinoline aluminum, oxadiazole compounds, quinone compounds, etc.; exemplarily, fullerenes and their derivatives include, but are not limited to, [6,6]-phenyl-C 61 methyl butyrate (PC) 61BM), [6,6]-phenyl-C 71 methyl butyrate (PC) 71 BM), Fullerene C 60 Fullerene C 61 Fullerene C 70 The imide compounds include, but are not limited to, one or more of perylene imide materials, naphthalene imide materials, phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide; metal oxides (which may be referred to as second metal oxides), perylene imide materials, naphthalene imide materials, etc. Among these, the metal oxides in the electron transport materials may include one or more of tin oxide, zinc oxide, etc. As a non-limiting example, in the electron transport materials, the metal element in the second metal oxide may include one or more of tin (Sn), magnesium (Mg), indium (In), molybdenum (Mo), titanium (Ti), and zinc (Zn). Metal sulfides include indium sulfide or zinc sulfide; metal fluorides include one or more of lithium fluoride (LiF), sodium fluoride, magnesium fluoride (MgF2), and calcium fluoride (CaF2).

[0252] Without limitation, the metal oxide in the first transport layer may refer to a first metal oxide (in which case the first transport layer is a hole transport layer) or a second metal oxide (in which case the first transport layer is an electron transport layer).

[0253] In some embodiments of this application, the first transport layer is a hole transport layer. In this case, in addition to the first metal oxide, the first transport layer may also include one or more other types of hole transport materials, as described above.

[0254] In some embodiments of this application, the first transport layer is an electron transport layer. In this case, in addition to the second metal oxide, the first transport layer may also include one or more other types of electron transport materials, as described above.

[0255] In this application, the terms "first metal oxide" and "second metal oxide" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0256] In some embodiments of this application, the thickness of the hole transport layer is 1 nm to 100 nm. For example, the thickness of the hole transport layer can be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc., or a range of any two of the above values, such as 1~10 nm, 10 nm~30 nm, 30 nm~50 nm, 40 nm~80 nm, 60 nm~100 nm, etc.

[0257] In some embodiments of this application, the thickness of the electron transport layer is 5nm to 100nm, specifically 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, etc., or a range of any two of the above values, for example, 5nm to 30nm, 30nm to 50nm, 40nm to 80nm, 60nm to 100nm, etc.

[0258] Non-limiting, the second electrode comprises a conductive material. The conductive material includes organic conductive materials, inorganic conductive materials, and organic-inorganic hybrid conductive materials.

[0259] As an example, organic-inorganic hybrid conductive materials include both organic and inorganic conductive components.

[0260] As a non-limiting example, organic conductive materials may include conductive polymers, wherein non-limiting examples of conductive polymers may include one or more of PEDOT (poly-3,4-ethylenedioxythiophene), polythiophene, polyacetylene, etc.

[0261] As a non-limiting example, inorganic conductive materials may include one or more of transparent conductive oxides, metallic conductive materials, and carbon conductive materials. Non-limiting examples of transparent conductive oxides may include one or more of FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), IZO (indium zinc oxide), and IWO (tungsten-doped indium oxide). Metallic conductive materials may include one or more of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), molybdenum (Mo), and tungsten (W).

[0262] In some embodiments of this application, non-limiting examples of inorganic conductive materials include metallic conductive materials. Further, metallic conductive materials may include any one of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), or any suitable mixture of the aforementioned elements.

[0263] It is understood that transparent electrodes include transparent conductive materials. In some embodiments of this application, the transparent conductive material contained in the transparent electrode may include conductive oxides. Non-limitingly, the conductive oxide in the transparent electrode may include one or more of indium tin oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, and aluminum-doped zinc oxide. In some embodiments of this application, the transparent conductive material in the transparent electrode may be exemplified, but is not limited to, one or more of the following materials: FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), IZO (indium zinc oxide), IWO (tungsten-doped indium oxide), etc.

[0264] In some embodiments of this application, the second electrode is a metal electrode. The metal electrode may include one or more metallic elements selected from gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), molybdenum (Mo), tungsten (W), etc.

[0265] In some embodiments of this application, the second electrode is a back electrode. The back electrode may include one or more of indium tin oxide (ITO), lanthanide-doped indium oxide, fluorine-doped tin oxide (FTO), antimony-doped tin oxide, boron-doped zinc oxide (BZO), zinc aluminum oxide (AZO), indium zinc oxide (IZO), zinc gallium oxide (GZO), and indium tungsten oxide (IWO), and the metal may include one or more metallic elements selected from Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, and Mg.

[0266] The substrate layer involved in the embodiments or examples of this application can be, but is not limited to, a rigid substrate layer or a flexible substrate layer. A non-limiting example of a rigid substrate layer is a glass substrate layer. In some embodiments, the rigid substrate layer is transparent glass. In some embodiments, the substrate layer is provided by a transparent conductive oxide film glass (TCO glass), wherein the glass serves as the substrate layer, and the TCO is a transparent conductive oxide film material; a non-limiting example of a TCO material is FTO, etc.

[0267] In some embodiments of this application, the material of the flexible substrate layer may be, for example, but not limited to, organic polymer materials. Furthermore, it may be composed of one or more of the following materials mixed in different proportions: including but not limited to polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), etc.

[0268] It is understood that the structure of the solar cell involved in this application is not limited to the structural layers listed above. Other functional layers or interface layers, such as interface modification layers and insertion layers, can also be introduced as needed. In some embodiments, the solar cell can be provided with an interface modification layer of appropriate energy level, which can play one or more of the following roles: reducing energy level barrier, promoting energy level matching, improving carrier extraction efficiency, passivating interface defect states, protecting the light-absorbing layer, inhibiting the oxidation and decomposition of the cell by water molecules and oxygen, improving photoelectric conversion efficiency, and improving device stability. Depending on the location of the interface modification layer, the type of interface modification layer can include four types: interface modification layer between hole transport layer and second electrode, interface modification layer between electron transport layer and first electrode, interface modification layer between hole transport layer and light-absorbing layer, and interface modification layer between electron transport layer and light-absorbing layer. Materials that can be used for interface modification layers in solar cells can include, but are not limited to, Cu2O, NiO, AZO, TiO2, etc. In some embodiments, an insertion layer can be provided between the electron transport layer and the second electrode. This insertion layer is used to block the transport of holes and can also be called a hole blocking layer. Examples of materials for the insertion layer include bath copper phosphate (BCP) and tin oxide.

[0269] In some embodiments of this application, the solar cell includes the following stacked structure: a transparent conductive glass substrate layer, a first hole transport layer, a perovskite layer, a first electron transport layer, a hole blocking layer (optional), and a back electrode (the back electrode can be a metal electrode or a transparent conductive electrode).

[0270] In this application, unless otherwise specified, "sequentially stacked" refers to the direction of stacking between layered structures and does not constitute a limitation on the structural composition of the stacked body. For example, "including stacked structural layer A and structural layer B" means that the stacking direction of structural layer A and structural layer B is along their respective thickness directions; that is, the thickness direction of structural layer A is consistent with or substantially consistent with the thickness direction of structural layer B. It is understood that other intermediate structural layers are allowed to be set between structural layer A and structural layer B.

[0271] In some embodiments of this application, the solar cell 100 includes Figure 3The structure shown includes a substrate layer 110, a first electrode 120, a first transport layer 130, a perovskite layer 140, a second transport layer 150, and a second electrode 160, arranged sequentially. The arrows indicate the light-incident side. Further, the structural layers are stacked sequentially. One of the first and second transport layers is an electron transport layer, and the other is a hole transport layer. In some embodiments, the first transport layer is a hole transport layer. In other embodiments, the first transport layer is an electron transport layer.

[0272] In some embodiments of this application, the solar cell includes Figure 4 The structure shown (a vertical cross-sectional view of the device) includes a substrate layer 110, a first electrode 120, a first hole transport layer 130, a perovskite layer 140, a first electron transport layer 150, and a second electrode 160, stacked sequentially. Furthermore, the solar cell has three cross-layer channel regions: a first channel region P1, a second channel region P2, and a third channel region P3. Utilizing the channel group formed by the first channel region P1, the second channel region P2, and the third channel region P3, the solar cell is divided into several series-connected sub-devices. Each sub-device includes a first channel region P1, a second channel region P2, and a third channel region P3 arranged sequentially, with the second channel region P2 located between the first channel region and the third channel region P3. The first channel region P1, the second channel region P2, and the third channel region P3 can be connected to the spaced-apart structural layers, thereby forming a circuit between the structural layers of the first electrode and the second electrode. The first channel region P1, the second channel region P2, and the third channel region P3 can each be an independent linear channel region, formed by laser etching. The number of each of the three channels can be one or more. The number of P1, P2, and P3 corresponds to the number of sub-solar cells. Non-limitingly, the first channel region P1, the second channel region P2, and the third channel region P3 can be configured as follows: the first channel region P1 is used to divide the first electrode 120 and must at least penetrate the first electrode 120; the second channel region P2 is used to penetrate and divide the first electron transport layer 150, the perovskite layer 140, and the first hole transport layer 130, and the two ends of the second channel region P2 are respectively connected to the second electrode 160 and the first electrode 120; the third channel region P3 is used to penetrate and divide the second electrode 160; optionally, the third channel region P3 is used to penetrate and divide the second electrode 160, the first electron transport layer 150, the perovskite layer 140, and the first hole transport layer 130, one end of the third channel region P3 is connected to the surface of the first electrode 120, and the other end extends out of the outer surface of the second electrode 160.

[0273] In some embodiments of this application, Figure 3-4 The substrate 110 in the structure shown is the light-incident side substrate.

[0274] In some embodiments of this application, the filling material in the first channel region P1 of the solar cell may be consistent with the first hole transport layer.

[0275] In some embodiments of this application, the filling material in the second channel region P2 of the solar cell may be consistent with the second electrode. In some embodiments, the width of the first channel region P1 is 10μm to 50μm, for example, 10μm, 20μm, 30μm, 40μm, 50μm, etc.

[0276] In some embodiments, the width of the second channel region P2 is 10μm to 200μm, such as 10μm, 20μm, 50μm, 100μm, 150μm, 160μm, 180μm, 200μm, etc. Further, the interval between the second channel region P2 and the first channel region P1 can be 20μm to 100μm, such as 20μm, 40μm, 60μm, 80μm, 100μm, etc.

[0277] In some embodiments, the width of the third channel region P3 is 10μm to 50μm, such as 10μm, 15μm, 20μm, 30μm, 40μm, 50μm, etc. Further, the interval between the third channel region P3 and the second channel region P2 can be 20μm to 100μm, such as 20μm, 30μm, 40μm, 80μm, 100μm, etc.

[0278] In some embodiments of this application, the solar cell includes an encapsulating adhesive layer. The encapsulating adhesive layer can be used to protect the stability of the solar cell, for example, to protect it from corrosion by water, oxygen, etc.

[0279] In some embodiments of this application, the encapsulating adhesive layer includes one or more of the following: epoxy encapsulating adhesive, silicone encapsulating adhesive, polyurethane encapsulating adhesive, UV-curable encapsulating adhesive, ethylene-vinyl acetate copolymer, polyvinyl butyral, ethylene-octene copolymer, polyisobutylene, and polyolefin encapsulating adhesive. The encapsulating adhesive layer can be stacked using existing techniques in the art. The encapsulating adhesive layer can be stacked at the final structural layer of the solar cell device after the solar cell has been fabricated. In some embodiments of this application, the final structural layer can be the second electrode. For example, lamination technology can be used to laminate the arranged solar cells or a module including solar cells with the encapsulating adhesive film, thereby creating the encapsulating adhesive layer on the side of the second electrode facing away from the light-absorbing layer. In this application, unless otherwise specified, the encapsulating film and encapsulating adhesive layer are transparent materials.

[0280] In some embodiments of this application, P1 in the solar cell can extend from the surface of the first transport layer to the bottom of the first electrode, and the filling material of P1 is consistent with the perovskite layer (e.g., Figure 4 (As shown). In other embodiments, P1 in the solar cell may extend from the surface of the first electrode to the bottom, and the filling material in P1 is consistent with the first transport layer.

[0281] In some embodiments of the second aspect of this application, a method for preparing a solar cell is provided, comprising the following steps: forming a first wet film on a first substrate by a first solution containing a perovskite precursor, followed by drying and a first annealing treatment to form a perovskite base film; the first substrate includes a first electrode, the first electrode including fluorine-doped tin oxide; the fluorine-doped tin oxide including an FTO crystal phase, the FTO crystal phase including an FTO (110) crystal plane;

[0282] The second solution containing the first additive is atomized and deposited on the surface of the perovskite base film to form a second wet film. After a second annealing treatment, a perovskite layer is formed.

[0283] The first additive includes at least one of fluorine-containing organic materials and sulfur-containing organic materials, the first annealing treatment time is 2 min to 8 min, and the first annealing treatment temperature is 120℃ to 150℃.

[0284] The perovskite layer includes a perovskite crystal phase, which includes a perovskite dominant crystal plane; the first electrode includes a first surface away from the perovskite layer, and the perovskite layer includes a second surface away from the first electrode. The region from the first surface to the second surface in the solar cell is denoted as the first structural region. Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (110) crystal plane is denoted as M1, where M1 ≥ 5. X-rays are incident on the first structural region from the direction from the second surface to the first surface.

[0285] Fluorine-containing and sulfur-containing organic additives can effectively passivate surface defects and reduce ion migration by interacting with unsaturated cations on the perovskite substrate surface through strong coordination or hydrogen bonding between fluoride / sulfide ions and fluorine / sulfide ions. When a second solution containing the first additive is atomized, a second wet film is formed on the surface of the perovskite substrate (denoted as the upper surface). The atomized droplets evaporate rapidly on the upper surface of the perovskite substrate after a very short residence time, and the first additive is instantly anchored to the upper surface and grain boundaries, rapidly reducing the surface energy of the upper surface, minimizing secondary nucleation, and allowing the crystal to continue growing downwards.

[0286] Understandably, the first substrate may include a first electrode, and the first solution may directly form a first wet film on the first electrode; the first substrate may also include a functional layer stacked with the first electrode, such as a transport layer or a barrier layer, in which case the first solution may form a first wet film on the functional layer.

[0287] Furthermore, after the surface energy of the upper surface decreases rapidly, the nucleation on the upper surface decreases, resulting in less consumption of the first additive, leaving a relatively large amount of the first additive remaining. Under the limited temperature and time of the first annealing, the crystal growth in the perovskite substrate film is incomplete, the grain boundaries are loose and rich in defects, and it is in a metastable state. The loose, porous grain boundaries and unclosed lattice provide a diffusion channel for the first additive molecules or the active substances generated by their decomposition to diffuse directly from the upper surface to the interface between the perovskite substrate film and the first electrode (denoted as the lower interface), which can achieve three-dimensional bulk defect passivation. In particular, the first additive will preferentially deposit in the area with the weakest structure and the most defects at the lower interface, i.e., the exposed area of ​​the first electrode. The second annealing process can promote the growth of the dominant perovskite crystal facets, increase their proportion, effectively passivate defects in the perovskite layer, improve its crystal quality, and promote secondary nucleation and growth of perovskite on the surface of the first electrode, thus improving the coverage of the first electrode. As a result, the dominant perovskite crystal facets have a higher proportion in the perovskite layer, and the FTO in the first electrode has a lower exposure, thereby increasing the peak height ratio of the diffraction peaks of the dominant perovskite crystal facets to the diffraction peaks of the FTO (110) crystal facets, thereby improving the macroscopic photoelectric conversion efficiency.

[0288] It should be noted that the surface energy of the perovskite (100) crystal facet decreases more after fluoride ion adsorption than that of the perovskite (110) crystal facet. Sulfide ions, due to their smaller steric hindrance, are more easily embedded in the perovskite (100) crystal facet. Therefore, fluorine-containing organic additives and sulfur-containing organic additives are beneficial to the growth of the perovskite (100) crystal facet, forming a perovskite layer dominated by the perovskite (100) crystal facet, and increasing the proportion of dominant crystal facets in the perovskite layer.

[0289] In some embodiments, the first annealing treatment time can be 2 min to 7 min, specifically 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, etc. This helps to control the growth and crystallization degree of the perovskite substrate film, keeping it in a metastable state, promoting the migration of the first additive from the upper surface to the interface between the perovskite substrate film and the first electrode (denoted as the lower interface), and providing conditions for the secondary nucleation and growth of the perovskite.

[0290] In some embodiments of this application, the first annealing temperature can be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, etc. This allows for the control of the growth and crystallization degree of the perovskite-based film.

[0291] In some embodiments, the step of atomizing a second solution containing a first additive and depositing it on the surface of a perovskite-based film to form a second wet film includes: atomizing a second solution containing a first additive to form an atomized second solution, and using an inert gas as a carrier gas to deposit the atomized second solution on the surface of the perovskite-based film to form a second wet film; optionally, the inert gas includes nitrogen.

[0292] This provides an oxygen-free and water-free environment, optimizes crystallization kinetics, improves the crystal quality of perovskite, and thus enhances the photoelectric conversion efficiency of solar cells. Using nitrogen as a carrier gas can reduce costs.

[0293] In some embodiments, the temperature of the second annealing treatment is 80℃~100℃, such as 80℃, 85℃, 90℃, 95℃, 100℃, etc.; the time of the second annealing treatment is 2min~15min, optionally 5min~10min, specifically 2min, 3min, 4min, 5min, 6min, 8min, 10min, 11min, 12min, 13min, 14min, 15min, etc. The above-mentioned conditions of the second annealing treatment can promote the continued growth of the perovskite dominant crystal facet, increase its proportion, and promote the effective passivation of defects in the perovskite layer by the first additive, thereby improving its crystal quality. At the same time, it can promote the secondary nucleation and growth of perovskite on the surface of the first electrode, improve the coverage of the first electrode. As a result, the perovskite dominant crystal facet has a high proportion in the perovskite layer, and the FTO in the first electrode has a low exposure degree, thereby increasing the peak height ratio of the diffraction peak of the perovskite dominant crystal facet to the diffraction peak of the FTO (110) crystal facet, thereby improving the macroscopic photoelectric conversion efficiency.

[0294] In some embodiments of this application, the fluorinated organic additive includes at least one selected from pentafluoroiodoethane, heptafluoro-1-iodopropane, 1-iodoperfluorodecane, and perfluorobromobutane. These fluorinated organic additives can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of solar cells by interacting with unsaturated cations on the perovskite substrate surface through strong coordination or hydrogen bonding via fluoride ions.

[0295] In some embodiments of this application, the sulfur-containing organic additive includes at least one of thioonium salts, disulfides, and organic sulfonates; further, the thioonium salt includes The compound shown in Formula I; wherein R1, R2, and R3 each independently comprise a C1-C4 alkyl group and an aryl group having 6-18 cyclic atoms; X' is a halogen atom; the disulfide includes the hydrochloride of CH3HN-R4-SS-R5-NH3CH3, wherein R4 and R5 each independently comprise a C1-C4 alkylene group; the organic sulfonate includes The compound shown in Formula II; R6 and R7 each independently comprise a C1-C4 alkylene group; M comprises at least one sodium ion and a potassium ion; furthermore, the thionium salt comprises dimethylphenylethylmercaptoiodide; the disulfide comprises 2,2'-dithionidinedimethylbis(N-methylethylamine) dihydrochloride; and the organic sulfonate comprises disodium 1,4-piperazine diethanesulfonate. The above-mentioned sulfur-containing organic additives can effectively passivate surface defects, reduce ion migration, and improve the photoelectric conversion efficiency of solar cells by interacting with unsaturated cations on the perovskite substrate surface through strong coordination or hydrogen bonding via sulfide ions.

[0296] In some embodiments of this application, the mass percentage of the first additive relative to the perovskite precursor is 0.07 wt% to 0.7 wt%, for example, 0.07 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, etc. When the mass percentage of the first additive relative to the perovskite precursor is within the above range, on the one hand, fluoride / sulfide ions can interact with unsaturated cations on the surface of the perovskite layer through strong coordination or hydrogen bonding, effectively passivating surface defects and reducing ion migration; on the other hand, it can reduce the risk of the first additive accumulating and crystallizing at grain boundaries or interfaces, forming a continuous insulating layer, and promote the lateral transport and vertical extraction of charge carriers between grains. This is beneficial for passivating surface defects while maintaining charge carrier transport efficiency, thereby improving the photoelectric conversion efficiency of the solar cell.

[0297] In some embodiments, the atomization method includes at least one of ultrasonic atomization and pneumatic atomization. Ultrasonic atomization utilizes high-frequency vibration to generate cavitation effects in the liquid, atomizing the solution into droplets. This is beneficial for obtaining droplets with uniform size, small size, and low kinetic energy, which improves the uniformity of contact between the first additive and the perovskite layer surface, promotes the anchoring of the first additive to the perovskite layer surface and grain boundaries, and enhances the passivation effect. Pneumatic atomization utilizes high-speed airflow to atomize the solution into droplets, offering high atomization efficiency and enabling larger flow rates. This is also beneficial for the contact between the first additive and the perovskite layer surface, enhancing the passivation effect.

[0298] In some embodiments of this application, the conditions for ultrasonic atomization include: ultrasonic power of 30kHz to 100kHz (e.g., 30kHz, 50kHz, 60kHz, 80kHz, 100kHz, etc.).

[0299] In some embodiments of this application, the conditions for pneumatic atomization include: an atomizing gas pressure of 0.05 MPa to 0.8 MPa (e.g., 0.05 MPa, 0.1 MPa, 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, etc.); and an atomizing gas flow rate of 10 mL / min to 100 mL / min (e.g., 10 mL / min, 20 mL / min, 40 mL / min, 50 mL / min, 60 mL / min, 80 mL / min, 100 mL / min, etc.). Further, the atomizing gas includes at least one of nitrogen and compressed air.

[0300] In some embodiments of this application, a second solution containing the first additive is atomized to form an atomized second solution. An inert gas is used as a carrier gas to deposit the atomized second solution onto the surface of the perovskite substrate to form a second wet film. Specific conditions are as follows: the second solution containing the first additive is ultrasonically atomized at 30kHz~100kHz (e.g., 30kHz, 50kHz, 60kHz, 80kHz, 100kHz, etc.) to form the atomized second solution. The distance from the nozzle to the substrate is set to 50mm~200mm (e.g., 50mm, 60mm, 80mm, 100mm, 120mm, 140mm, 160mm, 180mm, 200mm, etc.), the liquid flow rate is 0.1mL / min~5mL / min (e.g., 0.1mL / min, 0.5mL / min, 1mL / min, 2mL / min, 3mL / min, 4mL / min, 5mL / min, etc.), and the nozzle moving speed is 10... A second wet film is formed by depositing the atomized second solution containing the first additive onto the first perovskite substrate film at a pressure controlled at 0.1 bar to 0.6 bar (e.g., 0.1 bar, 0.2 bar, 0.3 bar, 0.4 bar, 0.5 bar, 0.6 bar). The second solution is used as the carrier gas and nitrogen is used as the carrier gas.

[0301] In some embodiments of this application, the first solution further includes a first solvent; the first solvent includes at least one of N,N-dimethylformamide and N-methylpyrrolidone.

[0302] In some embodiments of this application, the concentration of the perovskite precursor in the first solution is 0.1 mol / L to 5 mol / L, for example, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, etc.

[0303] In some embodiments of this application, the second solution further includes a second solvent; the second solvent includes chloroform.

[0304] In some embodiments of this application, the concentration of the first additive in the second solution is 0.05 g / mL to 1 g / mL, for example, 0.05 g / mL, 0.1 g / mL, 0.2 g / mL, 0.4 g / mL, 0.5 g / mL, 0.6 g / mL, 0.8 g / mL, 1 g / mL, etc.

[0305] A first solution containing a perovskite precursor forms a first wet film, which is then dried and subjected to a first annealing treatment to form a perovskite-based film. A second solution containing a first additive is atomized to form a second wet film on the surface of the perovskite-based film, which is then subjected to a second annealing treatment to form a perovskite layer.

[0306] Specifically, the solar cell is a formal cell, and its fabrication method includes the following steps:

[0307] Step 1: Prepare the base layer;

[0308] Step 2: Prepare a conductive layer on the substrate to form the first electrode;

[0309] Step 3: Fabricate an electron transport layer on the first electrode;

[0310] Step 4: Prepare a perovskite layer on the electron transport layer;

[0311] Step 5: Prepare a hole transport layer on the perovskite layer;

[0312] Step 6: Fabricate electrodes on the hole transport layer.

[0313] Specifically, the solar cell is an inverted solar cell, and its fabrication method includes the following steps:

[0314] Step 1: Prepare the base layer;

[0315] Step 2: Prepare a conductive layer on the substrate to form the first electrode;

[0316] Step 3: Fabricate a hole transport layer on a transparent conductive glass electrode;

[0317] Step 4: Prepare a perovskite layer on the hole transport layer;

[0318] Step 5: Prepare an electron transport layer on the perovskite layer;

[0319] Step 6: Fabricate electrodes on the electron transport layer.

[0320] Specifically, between steps 3 and 4, or between steps 4 and 5, a step of preparing a passivation layer may also be included.

[0321] If the fabrication is to produce a perovskite solar module, several laser processes P1 / P2 / P3 are added to the steps to divide the large-area cell into different small cells for series or parallel connection.

[0322] In some embodiments of the third aspect of this application, a photovoltaic module is provided, comprising at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect. The aforementioned photovoltaic module has improved photoelectric conversion efficiency.

[0323] In some embodiments of the fourth aspect of this application, an electrical device is provided, including at least one of the solar cells of the first aspect and the solar cells prepared by the preparation method of the second aspect.

[0324] The aforementioned electrical devices have improved photoelectric conversion efficiency.

[0325] In some embodiments of the fifth aspect of this application, a power generation device is provided, including at least one of the solar cells of the first aspect and the solar cells prepared by the preparation method of the second aspect.

[0326] The aforementioned power generation device has improved photoelectric conversion efficiency.

[0327] In some embodiments, the aforementioned solar cells can be used as power generation devices for electrical devices. The type of power generation device may include, but is not limited to, integrated power generation. The location of the power generation device may include, but is not limited to, the roof of a vehicle, the back panel, etc.

[0328] Furthermore, the aforementioned electrical devices may include mobile devices, such as mobile phones and laptops, electric vehicles, electric trains, ships and satellites, power generation systems, etc., but are not limited to these.

[0329] As an example, this is an electrical device. This device is a car, and can further be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0330] Another example of an electrical device could be a mobile phone, tablet, laptop, calculator, etc.

[0331] Another example of an electrical device could be a wearable device, such as a watch.

[0332] The following describes some embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where the technology or conditions are not specified in the embodiments, they are performed according to the description above, or according to the technology or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially, or can be synthesized from commercially available products using conventional methods.

[0333] In the following embodiments, "room temperature" refers to 20°C-30°C, and further, it can be 25°C.

[0334] In the following examples, unless otherwise specified, FTO is fluorine-doped tin oxide; DMF is N,N-dimethylformamide; and NMP is N-methylpyrrolidone.

[0335] Example 1

[0336] The solar cell uses an inverted pin structure and is fabricated as follows:

[0337] 1) Fabrication of the first electrode:

[0338] A set of FTO conductive glass with a specification of 300mm×400mm was used to etch P1 with ultraviolet laser. P1 is about 30μm wide. The entire glass was divided into 40 sub-cells along the long side. Each sub-cell is 6mm wide. The series resistance of different sub-cells is greater than 10MΩ. The top and bottom 10mm are used as the component welding area.

[0339] The etched conductive glass surface was cleaned twice with acetone and isopropanol, then immersed in deionized water for 10 minutes of ultrasonic treatment, and then dried in a forced-air drying oven. It was then placed in a drying room (humidity below 2%RH, relative humidity) and used as the first electrode (thickness 650nm).

[0340] 2) Hole transport layer fabrication:

[0341] a) Preparation of hole transport layer: The cleaned FTO conductive glass is placed in magnetron sputtering to deposit a layer of nickel oxide to form a hole transport layer (thickness of 20 nm).

[0342] 3) Preparation of electron blocking layer: A wet film (10 μm thick) of [4-(7H-dibenzocarbazole-7-yl)butyl]phosphoric acid (4PADCB) solution (0.50 mg / mL, ethanol solution) was coated on the hole transport layer using a slit coater. The film was then annealed at 100 °C for 5 min to form an electron blocking layer (1~1.5 nm thick).

[0343] 4) Preparation of the perovskite layer:

[0344] a) Preparation of perovskite precursor solution: Dissolve 8.60 g of formamidinium hydroiodate (FAI) and 23.05 g of lead iodide (PbI2) in 40 mL of DMF and 10 mL of NMP (first solvent, DMF and NMP volume ratio of 4:1), filter through a PTFE filter membrane with a pore size of 0.22 μm to obtain a 1 mol / L first solution;

[0345] b) The first solution slit is coated on the electron blocking layer to form a first wet film; then it is transferred to a vacuum pump and vacuumed for 80 s with a vacuum degree of 10 Pa. It is then annealed in an oven at 135°C for 5 min (first annealing treatment) and cooled to room temperature to form a perovskite-based film (FAPbI3, about 500 nm thick).

[0346] c) Dissolve 0.1582 g of the first additive (dimethylphenylethyl mercaptoiodide) in 80 mL of chloroform to prepare a second solution; after ultrasonically atomizing the second solution at 60 kHz, set the distance from the nozzle to the substrate to 100 mm, the liquid flow rate to 1 mL / min, the nozzle moving speed to 30 mm / s, use nitrogen as the carrier gas, and deposit the atomized second solution on the first perovskite substrate film at a pressure of 0.3 bar to form a second wet film, and anneal at 90 °C for 8 min (second annealing treatment) to form a perovskite layer (in the perovskite layer, the content of the first additive is 0.5 wt%).

[0347] 5) Fabrication of the electron transport layer: The substrate with the prepared perovskite layer is placed in a vacuum thermal evaporation apparatus and evacuated to a vacuum level of 4 × 10⁻⁶. -4 Pa, deposit 30nm C60 and 7nm BCP (bath copper spirit) as electron transport layers; laser etch P2, P2 width is 100μm, depth is etched to the FTO layer, and the spacing between P2 and P1 is 30μm;

[0348] 6) Fabrication of the second electrode: After depositing the electron transport layer, 80 nm Cu is deposited on the surface of the electron transport layer and then removed by vacuum breaking. P3 is laser etched with a width of 20 μm and a depth to the surface of the FTO layer. The spacing between P3 and P2 is 30 μm (the positions of the etching lines are P1 / P2 / P3 in sequence). Then, infrared edge cleaning is used on the module, that is, 10 mm is etched on each side of the module. The solar cell is thus obtained.

[0349] Examples 2-9 and Examples 11-13

[0350] Except for some differences in raw material composition and preparation process, the rest is the same as in Example 1. The differences are shown in Table 1.

[0351] The difference between Example 9 and Example 1 is that the second solution is atomized by air pressure. The specific conditions for air pressure atomization are as follows: a coaxial dual-fluid atomizing nozzle is used, high-purity nitrogen is used as the atomizing gas, the pressure of the atomizing gas is controlled at 0.2 MPa (gauge pressure), and the nitrogen volume flow rate displayed by the mass flow meter is about 50 mL / min (under standard conditions). The second solution is pushed by the injection pump and delivered to the nozzle at a flow rate of 5 mL / min to form the atomized second solution.

[0352] Example 10

[0353] Except that no carrier gas was used during the passivation layer deposition, and the atomized second solution was directly deposited on the perovskite substrate film, the rest was the same as in Example 1.

[0354] Comparative Example 1

[0355] Except for step 3c), the rest is the same as in Example 1.

[0356] Test case

[0357] 1. Crystal plane parameter testing of the perovskite layer and the first electrode: XRD was used for testing. The XRD testing equipment was a Bruker D8 Advance. The XRD testing procedure was as follows.

[0358] (1) Disassemble the solar cells of the examples and comparative examples to obtain a component sample (first structural region) consisting of a perovskite layer to a first electrode, fix it on the sample stage with conductive adhesive, and place it in a vacuum chamber;

[0359] (2) Use X-ray source: Cu Kα (wavelength λ=1.5406 Å), set 2Theta (2θ) scanning range 5~50°, scanning step size 0.016°, scanning speed 5° / min / second, and use the second surface (i.e. the surface of the perovskite layer away from the first electrode) as the X-ray incident surface.

[0360] (3) Start the X-ray diffractometer and begin the measurement. X-rays pass through the sample, interact with the crystal, and produce diffracted light, which is then received and recorded by the detector.

[0361] After the test, the background was subtracted by linear or polynomial fitting, and then the target peak was marked with a range. The peak height and half-width at half-maximum (FWHM) of the diffraction peaks of the (100) and (110) crystal planes corresponding to the perovskite layer, and the (100) and (200) crystal planes corresponding to the FTO were obtained by software, and M1, M2 and M3 were calculated. The average thickness of the crystal plane in the normal direction can be calculated by the Scherrer equation: D=Kλ / (βcosθ); where D is the average thickness of the crystal plane in the normal direction (unit: Å), K is the shape factor (0.89 in this application), λ is the X-ray wavelength (unit: nm), β is the half-width at half-maximum (FWHM) of the diffraction peak (in radians), and θ is the diffraction angle (in radians). The XRD pattern of the component (corresponding to the first structural region) formed by the perovskite layer to the first electrode in Example 1 is shown in Figure 7 .

[0362] 2. Average crystallinity test:

[0363] Testing was conducted using grazing incidence X-ray diffraction (GIXRD), and analysis was performed based on the characteristic diffraction peaks of the perovskite (100) crystal plane in a specific region of the perovskite layer. The testing equipment was a Bruker D8 Advance, as detailed below:

[0364] 1) Disassemble the solar cells of the examples and comparative examples to obtain a component sample (first structure region) consisting of a perovskite layer to a first electrode, and fix it on the sample stage with conductive adhesive (keeping the light-incident side facing the sample stage), and place it in a vacuum chamber;

[0365] 2) Using a copper target X-ray source (Cu Kα, λ = 1.5406 Å), set an appropriate 2Theta scanning range and set a series of grazing incidence angles (ω): 0.2° and 1.0°. Probe from the second surface (i.e. the surface of the perovskite layer away from the first electrode) at depths of 50 nm (corresponding to the first region) and 500 nm (corresponding to the entire perovskite layer) extending downward from the upper surface.

[0366] 3) Start the X-ray diffractometer to begin the measurement. X-rays pass through the sample, interact with the crystal, and produce diffracted light, which is then received and recorded by the detector.

[0367] After the test is completed, the background is subtracted by linear or polynomial fitting, and then the target peak is marked with a range. The half-peak width of the diffraction peak corresponding to the (100) crystal plane is obtained by software.

[0368] 3. Initial device performance (optoelectronic devices used in solar cells):

[0369] Under normal temperature and pressure (25℃, 1 atmosphere), a standard light source with AM1.5G was used to simulate sunlight, conforming to the national standard IEC61215. The light intensity was corrected using crystalline silicon solar cells to achieve the intensity of one solar cell. The current-voltage characteristic curve (i.e., current-voltage curve) of the solar cell under the illumination of the light source was measured using a four-channel digital source meter (Keithley 2440). The open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and photoelectric conversion efficiency (PCE) of the solar cell were obtained.

[0370] The photoelectric conversion efficiency (PCE) is calculated as follows:

[0371] PCE = Pout / Pin

[0372] = Voc×Jsc×[(Vmpp×Jmpp) / (Voc×Jsc)] / Pin

[0373] = Voc×Jsc×FF / Pin

[0374] Wherein, Pout, Pin, Voc, Jsc, Vmpp, Jmpp, and FF represent the battery's operating output power, incident light power, open-circuit voltage, short-circuit current, maximum power point voltage, maximum power point current, and fill factor, respectively. The incident light power is 100 mW / cm². 2 .

[0375] 4. Surface morphology observation: The grain morphology of the perovskite layer interface was observed by SEM. The SEM testing equipment was ZEISS Gemini 360. The specific testing steps are as follows: (1) Fix the sample on the sample stage and put it into the electron microscope vacuum chamber; (2) Select the appropriate working voltage (3kV), working distance (5mm) and magnification (5k-50k times), and take pictures of typical areas in the secondary electron imaging mode. The results of Example 1 are shown in Figure 5 The results of Example 2 are shown in Figure 6 .

[0376] Table 1

[0377]

[0378] Table 2

[0379]

[0380] Note: In Table 2, “first region” refers to the half-width at half-maximum (WHM) of the diffraction peaks of the perovskite (100) crystal plane in the first region, in °; “perovskite layer” refers to the half-width at half-maximum (WHM) of the diffraction peaks of the perovskite (100) crystal plane in the perovskite layer, in °.

[0381] As shown in Table 1, the solar cells prepared in this application have a peak height ratio M1≥5 between the diffraction peaks of the dominant perovskite crystal plane (perovskite (100) crystal plane) and the diffraction peaks of the FTO (110) crystal plane, indicating better photoelectric conversion efficiency, significantly superior to Comparative Example 1. Furthermore, comparing Examples 1 and 9 shows that ultrasonic atomization, compared to pneumatic atomization, is beneficial for improving the atomization effect, promoting the growth and secondary nucleation of the perovskite (100) crystal plane, increasing the average thickness of the perovskite (100) crystal plane in the normal direction, and obtaining higher M1 and M2 values, thereby improving the photoelectric conversion efficiency. Comparing Examples 1 and Comparative Examples 10-13 shows that M2, M3, and M4 also have a certain impact on the photoelectric conversion efficiency. Specifically, Examples 1 and 10 show that using a carrier gas after atomizing the second solution is beneficial for further improving the photoelectric conversion efficiency, which may be due to the inert environment provided by the carrier gas and the improved deposition uniformity. As can be seen from Examples 1 and 11-12, controlling the second annealing time within the preferred range (5 min to 10 min) is beneficial for promoting secondary nucleation and crystallization of perovskite. This increases the proportion of dominant crystal planes in the perovskite layer and reduces the exposure of the first electrode, thereby improving photoelectric efficiency. As can be seen from Examples 1 and 13, controlling the first annealing time within the range of 2 min to 7 min is beneficial for further increasing the M1 value and improving photoelectric conversion efficiency. This may be due to the perovskite substrate film being in a metastable state, which facilitates the penetration of the first additive to the interface of the first electrode, exerting a passivating effect and promoting secondary nucleation of perovskite.

[0382] It is understood that the solar cells described above are not limited to those prepared by the methods used in the embodiments. The above embodiments are merely illustrative examples, and those skilled in the art may also use other preparation methods to obtain the solar cells protected by the first aspect of this application. For example, the first additive and passivation process may not be used, but other process parameters (such as material composition, annealing conditions, etc.) may be adjusted to obtain the solar cells protected by the first aspect of this application. This application does not limit the preparation method of the solar cells protected by the first aspect.

[0383] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solar cell, characterized in that, The device includes a first electrode and a perovskite layer stacked together; the first electrode includes fluorine-doped tin oxide; the fluorine-doped tin oxide includes an FTO crystal phase, the FTO crystal phase includes an FTO (110) crystal plane; the perovskite layer includes a perovskite crystal phase, the perovskite crystal phase includes a perovskite dominant crystal plane; The first electrode includes a first surface remote from the perovskite layer, and the perovskite layer includes a second surface remote from the first electrode. The region from the first surface to the second surface in the solar cell is referred to as the first structural region. Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (110) crystal plane is denoted as M1, where M1≥5; wherein, X-rays are incident on the first structural region from the second surface to the first surface.

2. The solar cell as described in claim 1, characterized in that, M1 is 5~15, and can be selected as 5~12.

3. The solar cell as described in claim 1 or 2, characterized in that, The dominant crystal plane of the perovskite is the perovskite (100) crystal plane.

4. The solar cell as described in claim 3, characterized in that, The perovskite crystal phase also includes the perovskite (110) crystal plane; Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite (100) crystal plane to that of the diffraction peak of the perovskite (110) crystal plane is denoted as M2, where M2≥5 and can be selected as M2≥8.

5. The solar cell as described in claim 4, characterized in that, M2 is 5~28, and can be selected as 8~28, and further selected as 8~25.

6. The solar cell according to any one of claims 1 to 5, characterized in that, The fluorine-doped tin oxide also includes an FTO (200) crystal plane; Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the dominant perovskite crystal plane to the diffraction peak of the FTO (200) crystal plane is denoted as M3, where M3 ≥ 6.

7. The solar cell according to any one of claims 1 to 6, characterized in that, The perovskite crystal phase includes a perovskite (100) crystal plane, and the average thickness of the perovskite (100) crystal plane in the normal direction is denoted as D. 100 D 100 ≥600Å; optionally, 600Å≤D 100 ≤1000Å.

8. The solar cell according to any one of claims 1 to 7, characterized in that, The perovskite crystal phase includes a perovskite (110) crystal plane, and the average thickness of the perovskite (110) crystal plane in the normal direction is denoted as D. 110 D 110 ≥ 200Å; optionally, 200Å ≤ D 110 ≤385Å.

9. The solar cell according to any one of claims 1 to 8, characterized in that, The thickness of the perovskite layer is denoted as H. The region extending d1 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the first region, where H / 10-20nm≤d1≤H / 10+20nm. The average crystallinity of the perovskite phase in the first region is less than the average crystallinity of the perovskite phase in the perovskite layer.

10. The solar cell according to claims 1 to 9, characterized in that, Based on the XRD diffraction pattern of the first structural region, the ratio of the full width at half maximum (FWHM) of the diffraction peak of the dominant perovskite crystal plane in the first region to the FWHM of the diffraction peak of the dominant perovskite crystal plane in the perovskite layer is denoted as M4, where M4 is 1:(0.3~0.8).

11. The solar cell as claimed in claim 10, characterized in that, The full width at half maximum (FWHM) of the diffraction peaks of the dominant perovskite crystal plane of the perovskite layer is 0.085°~0.131°.

12. The solar cell according to any one of claims 1 to 11, characterized in that, The perovskite layer includes a first perovskite material, the first perovskite material including FA. 1-x1 Cs x1 PbBr x2 I 3-x2 Where x1 is 0~0.8 and x2 is 0~0.

8.

13. The solar cell according to any one of claims 1 to 12, characterized in that, It meets one or more of the following characteristics: (1) The thickness of the perovskite layer is 200nm~1000nm, and can be selected as 300nm~600nm; (2) On a projection plane perpendicular to the thickness direction of the perovskite layer, the area of ​​the perovskite layer is greater than or equal to 0.07 m². 2 .

14. The solar cell according to any one of claims 1 to 13, characterized in that, The solar cell is a multi-junction solar cell, which includes a first cell unit, the first cell unit including the first electrode and the perovskite layer.

15. The solar cell according to claim 14, characterized in that, The multijunction solar cell further includes a second cell stacked with the first cell; the second cell and the first cell are connected by an interconnect layer, or the second cell and the first cell are isolated by an insulating layer; the second cell includes a second light-absorbing layer, and the band gap of the second light-absorbing layer is different from that of the perovskite layer.

16. The solar cell according to claim 14 or 15, characterized in that, The second light-absorbing layer in the second battery cell includes a semiconductor active material, which includes one or more of the following: a second perovskite material, a silicon-containing semiconductor material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, gallium arsenide, and organic active materials.

17. The solar cell according to any one of claims 14 to 16, characterized in that, The multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together; wherein the interconnect layer is located between the perovskite layer and the second light-absorbing layer; the first electrode is located on the side of the perovskite layer away from the interconnect layer, and the second electrode is located on the side of the second light-absorbing layer away from the interconnect layer.

18. The solar cell according to any one of claims 14 to 16, characterized in that, The multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together; wherein the third electrode, the insulating layer, and the fourth electrode are stacked between the perovskite layer and the second light-absorbing layer, the third electrode is disposed on the side of the insulating layer facing the perovskite layer, the fourth electrode is disposed on the side of the insulating layer facing the second light-absorbing layer, the first electrode is located on the side of the perovskite layer away from the third electrode, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode.

19. The solar cell according to any one of claims 1 to 18, characterized in that, It meets one or more of the following characteristics: (1) The perovskite layer is contained in the inverse or formal structure of the solar cell; (2) The solar cell further includes a second transport layer, wherein the perovskite layer is stacked between the first transport layer and the second transport layer; wherein, one of the first transport layer and the second transport layer is a hole transport layer and the other is an electron transport layer.

20. A method for preparing a solar cell, characterized in that, Includes the following steps: A first wet film is formed on a first substrate by a first solution containing a perovskite precursor, and then dried and subjected to a first annealing treatment to form a perovskite base film; the first substrate includes a first electrode, the first electrode including fluorine-doped tin oxide; the fluorine-doped tin oxide includes an FTO crystal phase, the FTO crystal phase including an FTO (110) crystal plane; The second solution containing the first additive is atomized and deposited on the surface of the perovskite-based film to form a second wet film. After a second annealing treatment, a perovskite layer is formed. The first additive includes at least one of fluorine-containing organic additives and sulfur-containing organic additives, the first annealing treatment time is 2 min to 8 min, and the first annealing treatment temperature is 120℃ to 150℃. The perovskite layer includes a perovskite crystal phase, and the perovskite crystal phase includes a perovskite dominant crystal plane; the first electrode includes a first surface away from the perovskite layer, and the perovskite layer includes a second surface away from the first electrode. The region from the first surface to the second surface in the solar cell is denoted as the first structural region. Based on the XRD diffraction pattern of the first structural region, the peak height ratio of the diffraction peak of the perovskite dominant crystal plane to the diffraction peak of the FTO (110) crystal plane is denoted as M1, where M1 ≥ 5. X-rays are incident on the first structural region from the direction from the second surface to the first surface.

21. The preparation method according to claim 20, characterized in that, The step of atomizing a second solution containing a first additive and depositing it on the surface of the perovskite-based film to form a second wet film includes: atomizing a second solution containing a first additive to form an atomized second solution, and using an inert gas as a carrier gas to deposit the atomized second solution on the surface of the perovskite-based film to form a second wet film. Optionally, the inert gas includes nitrogen.

22. The preparation method according to any one of claims 20-21, characterized in that, The temperature of the second annealing treatment is 80℃~100℃, and the time of the second annealing treatment is 2min~15min, which can be selected as 5min~10min.

23. The preparation method according to any one of claims 20 to 22, characterized in that, It meets one or more of the following characteristics: (1) The fluorinated organic additives include at least one of pentafluoroiodoethane, heptafluoro-1-iodopropane, 1-iodoperfluorodecane and perfluorobromobutane; (2) The sulfur-containing organic additives include at least one of thionium salts, disulfides and organic sulfonates; Optionally, the thionium salt includes dimethylphenylethylmercaptoiodide; the disulfide includes 2,2'-dithionidinedimethylbis(N-methylethylamine) dihydrochloride; and the organic sulfonate includes disodium 1,4-piperazine diethanesulfonate. (3) The first additive accounts for 0.07wt% to 0.7wt% of the mass of the perovskite precursor; (4) The atomization method includes at least one of ultrasonic atomization and air pressure atomization.

24. A photovoltaic module, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 19 and the solar cells prepared by the preparation method according to any one of claims 20 to 23.

25. An electrical appliance, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 19 and the solar cells prepared by the preparation method according to any one of claims 20 to 23.

26. A power generation device, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 19 and the solar cells prepared by the preparation method according to any one of claims 20 to 23.

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