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 perovskite layer, the perovskite layer comprises non-chlorine monovalent anions, and the non-chlorine monovalent anions are selected from a group consisting of non-chlorine halogen anions and pseudo-halogen anions; the perovskite layer further comprises a chlorine element; the first relative concentration of the chlorine element of the perovskite layer is M0, and M0 is greater than 0 and less than or equal to 6%; the first relative concentration of the chlorine element in the first region is greater than the first relative concentration of the chlorine element in the second region. The solar cell can improve photoelectric conversion efficiency and long-term stability.

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] Solar cells are devices that convert light energy into electrical energy using a photoelectric conversion mechanism. With advantages such as high conversion efficiency, high response speed, long lifespan, low energy consumption, small size, and environmental friendliness, solar cells have shown enormous development potential in the new energy field. Semiconductor active materials are the core of photoelectric conversion in solar cells. Among them, perovskite materials, with their tunable bandgap, high defect tolerance, and low-temperature solution film formation capabilities, are widely used as semiconductor active materials in solar cells. However, the photoelectric conversion efficiency and long-term stability of solar cells still need 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 long-term stability, a method for preparing the same, as well as an electrical device and a power generation device.

[0004] In a first aspect, this application provides a solar cell including a perovskite layer, the perovskite layer including non-chlorine monovalent anions, the non-chlorine monovalent anions being selected from the group consisting of non-chlorine halide anions and pseudohalogen anions;

[0005] The perovskite layer also includes chlorine;

[0006] The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%;

[0007] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0008] The first relative concentration of chlorine in the first region is greater than the first relative concentration of chlorine in the second region.

[0009] Non-chlorine monovalent anions, as one of the main components of the perovskite layer, have a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the defined first relative concentration of chlorine can characterize the chlorine content distribution in the perovskite layer. By introducing chlorine into the perovskite layer, on the one hand, chlorine near the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase (such as in the second region) can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, by controlling the chlorine content in the perovskite layer within the above-mentioned range, it is beneficial to reduce perovskite defects while taking into account the crystal quality and resistivity of the perovskite layer, thereby improving the performance of solar cells. This invention improves the photoelectric conversion efficiency and long-term stability of the solar cell. Simultaneously, by controlling the first relative concentration of chlorine in the first region to be greater than that in the second region, the chlorine concentration near the perovskite layer interface can be controlled to be greater than that in the middle of the perovskite bulk phase. This ensures that the chlorine concentration in the corresponding region matches the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as near the surface and in the middle of the bulk phase), improving the overall uniformity of the perovskite layer structure, while also considering the overall amount of chlorine used. In other words, a smaller amount of chlorine is needed to achieve the goals of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality. Furthermore, by passivating perovskite defects and improving the crystal quality of the perovskite layer, ion migration can be suppressed, water-oxygen erosion can be blocked, non-radiative recombination can be reduced, and the long-term stability of the solar cell can be improved. Therefore, this application can effectively reduce perovskite defects while considering the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0010] In some embodiments, the first relative concentration of chlorine in the perovskite layer is 0.004% to 5.17%, optionally 0.08% to 4%.

[0011] Controlling the first relative concentration of chlorine in the perovskite layer within the above-mentioned range can effectively reduce perovskite defects and better balance the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0012] In some embodiments, one or more of the following features are satisfied:

[0013] (1) The first relative concentration of chlorine in the first region is 0.003%~1.5%, and can be selected as 0.05%~1.5%;

[0014] (2) The first relative concentration of chlorine in the second region is 0.00001% ~ 0.05%, which can be selected as 0.0005% ~ 0.05%.

[0015] By controlling the first relative concentration of chlorine in the first region within the aforementioned range, chlorine can more effectively passivate defects near the interface of the perovskite layer close to the first surface, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0016] By controlling the first relative concentration of chlorine in the second region within the aforementioned range, the chlorine can more fully passivate the defects in the bulk phase of the perovskite layer, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0017] Controlling the concentration of chlorine in one or more of the first relative concentrations in the first and second regions within the aforementioned range is beneficial for simultaneously and sufficiently passivating defects near the interface close to the first surface and in the bulk phase of the perovskite layer. It also improves the uniformity of the overall structure of the perovskite layer, thereby enhancing the photoelectric conversion efficiency and long-term stability of the solar cell.

[0018] In some embodiments, the ratio of the first relative concentration of chlorine in the first region to the first relative concentration in the second region is (29~105):1, and can be (32~88):1.

[0019] Controlling the ratio of the first relative concentration of chlorine in the first region to the first relative concentration in the second region within the above range is beneficial for enriching chlorine in the first region and reducing the chlorine content in the perovskite layer bulk phase. This allows for better matching of the appropriate chlorine concentration required to passivate defects in different regions, and better improvement of the overall uniformity of the perovskite layer structure. Consequently, it is beneficial for improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0020] In some embodiments, a region with a thickness of 5 nm to 10 nm exists within a region extending 20 nm from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer, and is referred to as the third region;

[0021] The first relative concentration of chlorine in the third region is greater than the first relative concentration of chlorine in the second region.

[0022] By controlling the concentration of chlorine in the third region to be greater than that in the second region, it is beneficial to form a quasi-two-dimensional thin film with the perovskite material near the interface close to the second surface (such as in the second region), thereby reducing defects near the interface close to the second surface, passivating the perovskite grain boundaries, and increasing the open-circuit voltage. On the other hand, it is also beneficial to allow chlorine to simultaneously and fully passivate defects near the second surface and in the bulk phase of the perovskite layer, which is conducive to improving the uniformity of the overall structure of the perovskite layer. This is beneficial to improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0023] In some embodiments, the first relative concentration of chlorine in the third region is less than the first relative concentration of chlorine in the first region;

[0024] Optionally, the first relative concentration of chlorine in the third region is 0.0005% to 0.6%, and optionally 0.01% to 0.5%.

[0025] Therefore, on the one hand, chlorine near the first surface of the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine near the interface of the second surface in the perovskite layer (such as in the third region) forms a quasi-two-dimensional thin film with the perovskite material, reducing defects near the interface of the second surface, passivating perovskite grain boundaries, and increasing open-circuit voltage. Simultaneously, by controlling the first relative concentration of chlorine in the third region to be less than the first relative concentration of chlorine in the first region, the concentration of chlorine near the first surface of the perovskite layer can be controlled to be greater than the concentration near the second surface. This ensures that the chlorine concentration in the corresponding region matches the number of defects in that region, facilitating the simultaneous and sufficient passivation of defects near both the first and second surfaces of the perovskite layer by chlorine, and improving the overall uniformity of the perovskite layer structure. This, in turn, contributes to better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0026] Furthermore, controlling the first relative concentration of chlorine in the third region within the aforementioned range is beneficial for fully passivating defects near the interface close to the second surface (such as in the third region), while also better maintaining the uniformity of the overall perovskite layer structure, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0027] In some embodiments, a region extending d1 from the first surface toward the interior of the perovskite layer along the thickness direction of the perovskite layer is designated as the fourth region, where 1 / 2×H-10nm≤d1≤1 / 2×H+10nm; the direction from the first surface to the second surface along the thickness direction from near the first surface to the side away from the first surface is designated as the Z1 direction, and the first relative concentration of chlorine in the fourth region generally decreases along the Z1 direction.

[0028] This helps to match the chlorine concentration in the corresponding region with the number of defects in that region, which in turn helps to passivate the defects in the fourth region of the perovskite layer with chlorine, and improves the uniformity of the overall structure of the perovskite layer. This, in turn, helps to improve the photoelectric conversion efficiency and long-term stability of the solar cell.

[0029] In some embodiments, the region extending d2 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the fifth region, where 1 / 2×H-10nm≤d2≤1 / 2×H+10nm; the direction from the first surface to the second surface along the thickness direction of the perovskite layer from the side near the first surface is denoted as the Z1 direction, and the first relative concentration of chlorine in the fifth region generally shows an increasing trend in the Z1 direction.

[0030] This helps to match the chlorine concentration in the corresponding region with the number of defects in that region, which in turn helps to passivate the defects in the fifth region of the perovskite layer with chlorine, and improves the uniformity of the overall structure of the perovskite layer. This, in turn, helps to improve the photoelectric conversion efficiency and long-term stability of the solar cell.

[0031] In a second aspect, this application provides a solar cell including a perovskite layer, the perovskite layer including non-chlorine monovalent anions, the non-chlorine monovalent anions being selected from the group consisting of non-chlorine halide anions and pseudohalogen anions;

[0032] The perovskite layer also includes chlorine; the molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, 0 < M0 ≤ 6%;

[0033] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0034] The first percentage of chlorine is defined as the ratio of the amount of chlorine in a preset region to the total amount of chlorine in the perovskite layer. The first percentage of chlorine in the first region is greater than the first percentage of chlorine in the second region.

[0035] As one of the main components of the perovskite layer, the non-chlorine monovalent anion has a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the first relative concentration of chlorine can characterize the content distribution of chlorine in the perovskite layer. By introducing chlorine into the perovskite layer, on the one hand, near-surface chlorine can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, controlling the chlorine content in the perovskite layer within the above-mentioned range is beneficial for reducing perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell. At the same time, by controlling the chlorine content in the first region to be greater than that in the second region, the chlorine content in the corresponding region is matched with the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as near-surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, while taking into account the overall amount of chlorine used, that is, the purpose of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality can be achieved with a smaller amount of chlorine. Therefore, this application can effectively reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0036] In some embodiments, the first substance of chlorine in the first region accounts for 6% to 15% of the total amount, and may be 9% to 15%.

[0037] By controlling the proportion of chlorine in the first region within the aforementioned range, chlorine can more effectively passivate defects near the interface of the perovskite layer close to the first surface, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0038] In some embodiments, the first substance of chlorine in the second region accounts for 0.3% to 2% of the total amount, and may be 0.4% to 1%.

[0039] Optionally, the ratio of the amount of chlorine in the first substance in the first region to the amount of chlorine in the second region is (10~35):1.

[0040] By controlling the proportion of the first substance of chlorine in the second region within the aforementioned range, the chlorine element can more fully passivate the defects in the bulk phase of the perovskite layer, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0041] Furthermore, controlling the ratio of the first molar proportion of chlorine in the first region to the first molar proportion of chlorine in the second region within the aforementioned range is beneficial for enriching chlorine in the first region and reducing the chlorine content in the perovskite layer bulk phase. This better matches the appropriate chlorine concentration required for passivating defects in different regions, and better improves the uniformity of the overall structure of the perovskite layer, thereby contributing to better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0042] In some embodiments, a region with a thickness of 5 nm to 10 nm exists within a region extending 20 nm from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer, and is referred to as the third region;

[0043] The proportion of chlorine in the third region is greater than that in the second region.

[0044] By controlling the proportion of chlorine in the first substance of the third region to be greater than that in the second region, it is beneficial to form a quasi-two-dimensional thin film with the perovskite material near the interface of the second surface in the perovskite layer (such as in the second region), thereby reducing defects near the interface of the second surface in the perovskite, passivating the perovskite grain boundaries, and increasing the open-circuit voltage. On the other hand, it is also beneficial to allow chlorine to simultaneously and fully passivate defects near the second surface of the perovskite layer and in the bulk phase, which is beneficial to improving the uniformity of the overall structure of the perovskite layer. This is conducive to improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0045] In some embodiments, the first substance of chlorine in the third region accounts for 5% to 14%, and may be 5% to 10%.

[0046] Controlling the proportion of chlorine in the third region within the above range is beneficial for fully passivating defects near the interface close to the second surface (such as in the third region), while also better maintaining the uniformity of the overall perovskite layer structure, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0047] In some embodiments, the proportion of chlorine in the third region is less than the proportion of chlorine in the first region.

[0048] Therefore, on the one hand, chlorine near the first surface of the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine near the interface of the second surface in the perovskite layer (such as in the third region) forms a quasi-two-dimensional thin film with the perovskite material, reducing defects near the interface of the second surface, passivating perovskite grain boundaries, and increasing open-circuit voltage. Simultaneously, by controlling the proportion of the first substance in the third region to be less than the proportion of chlorine in the first substance in the first region, the chlorine concentration near the first surface of the perovskite layer can be controlled to be greater than the chlorine concentration near the second surface. This ensures that the chlorine concentration in the corresponding region matches the number of defects in that region, facilitating the simultaneous and sufficient passivation of defects near both the first and second surfaces of the perovskite layer by chlorine, and improving the overall uniformity of the perovskite layer structure. This, in turn, contributes to better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0049] In some embodiments, the region extending d1 from the first surface toward the interior of the perovskite layer along the thickness direction of the perovskite layer is referred to as the fourth region, where 1 / 2×H-10nm≤d1≤1 / 2×H+10nm; the direction from the first surface to the second surface in the thickness direction of the perovskite layer is referred to as the Z1 direction, and the first molar percentage of chlorine in the fourth region generally decreases in the Z1 direction.

[0050] This helps to match the chlorine concentration in the corresponding region with the number of defects in that region, which in turn helps to passivate the defects in the fourth region of the perovskite layer with chlorine, and improves the uniformity of the overall structure of the perovskite layer. This, in turn, helps to improve the photoelectric conversion efficiency and long-term stability of the solar cell.

[0051] In some embodiments, the region extending d2 from the second surface toward the interior of the perovskite layer along the thickness direction of the perovskite layer is referred to as the fifth region, where 1 / 2×H-10nm≤d2≤1 / 2×H+10nm; the direction from the first surface to the second surface in the thickness direction of the perovskite layer is referred to as the Z1 direction, and the first substance proportion of chlorine in the fifth region generally shows an increasing trend in the Z1 direction.

[0052] This facilitates a match between the chlorine concentration in the corresponding region and the number of defects in that region, allowing chlorine to simultaneously and effectively passivate defects in the fifth region of the perovskite layer. It also improves the overall uniformity of the perovskite layer structure, thereby enhancing the photoelectric conversion efficiency and long-term stability of the solar cell. Furthermore, by passivating perovskite defects and improving the crystallinity of the perovskite layer, ion migration can be suppressed, water-oxygen erosion can be blocked, and non-radiative recombination can be reduced, further contributing to improved long-term stability of the solar cell.

[0053] In some embodiments, the average molar volume concentration of chlorine in the perovskite layer is 0.000001 mmol / cm³. 3 ~0.00001mmol / cm 3 .

[0054] By controlling the average molar volume concentration of the perovskite layer within the above range, it is beneficial to reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0055] In some embodiments, the solar cell includes a first transport layer stacked with the perovskite layer; the first transport layer includes chlorine.

[0056] Introducing chlorine into the first transport layer helps passivate the interface between the first transport layer and the perovskite layer, improves the energy level matching between the two layers, enhances their compatibility and the stability of the charge transport interface, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0057] In some embodiments, the first transport layer comprises nickel oxide.

[0058] Nickel oxide has excellent chemical and thermal stability, high energy level matching with perovskite layers, low optical loss, good process compatibility, and low cost, which is beneficial for improving the photoelectric conversion efficiency of solar cells.

[0059] Furthermore, when the first transport layer includes nickel oxide, controlling the enrichment of chlorine in a first region of the perovskite layer (e.g., by controlling the first relative concentration or the first molar percentage in the first region to be higher than that in the second region) facilitates the passivation of Ni through coordination. 3+ Suppress Ni 3+ Migration into the perovskite layer helps to leverage the aforementioned advantages of nickel oxide while also effectively reducing Ni content. 3+ The degradation of perovskite crystals improves the structural stability of the perovskite layer, which in turn helps to improve photoelectric conversion efficiency and long-term stability.

[0060] In some embodiments, the direction from the second surface to the first surface in the thickness direction of the perovskite layer is denoted as the Z2 direction;

[0061] The proportion of the amount of chlorine in the preset region of the first transport layer relative to the total amount of chlorine in the first transport layer is denoted as the second proportion of chlorine; the proportion of the second proportion of chlorine in the first transport layer generally shows an upward trend in the Z2 direction.

[0062] At this point, it is beneficial to more effectively exert passivation and suppress Ni in the first transport layer. 3+ Migration helps to better reduce Ni migration into the perovskite layer. 3+ The content of these substances helps to improve photoelectric conversion efficiency and long-term stability. In addition, it can also help improve the long-term stability of solar cells.

[0063] In some embodiments, the molar percentage of chlorine in a preset region of the first transport layer relative to the nickel in the preset region is denoted as the second relative concentration of chlorine in the preset region, and the second relative concentration of chlorine in the first transport layer is 15% to 40%.

[0064] This helps to reduce the amount of Ni that migrates out. 3+ The content of Ni is reduced, thereby lowering the Ni content. 3+ This reduces the adverse effects on the first perovskite material and further modulates the energy levels of the first transport layer and the perovskite layer, improving their compatibility and the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0065] In some embodiments, the non-chlorine monovalent anion includes iodide ions;

[0066] Optionally, based on the total amount of non-chlorinated monovalent anions in the perovskite layer, the proportion of iodide ions in the perovskite layer is 80.0% to 99.8%.

[0067] Iodide ions have a large radius, which can cause lattice expansion, thus facilitating band gap adjustment. Furthermore, iodide ions promote the formation of perovskite materials with symmetrical crystal phase structures, reducing local strain and defect density, and lowering the resistivity of perovskite materials. Therefore, they can improve the photoelectric conversion efficiency and long-term stability of solar cells. Controlling the iodide ion content within the aforementioned range helps reduce perovskite defects while balancing the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0068] In some embodiments, the non-chlorine monovalent anion includes bromide ions;

[0069] Optionally, based on the total amount of non-chlorine monovalent anions in the perovskite layer, the proportion of bromide ions in the perovskite layer is 0.2% to 20%.

[0070] Bromine ions have a small radius, which is beneficial for shrinking the crystal lattice, reducing the strain gradient, improving the uniformity of the crystal structure, and improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0071] In some embodiments, the perovskite layer comprises a first perovskite material, the first perovskite material comprising the non-chlorine monovalent anion.

[0072] Non-chlorine monovalent anions are beneficial for achieving charge balance and maintaining crystal structure stability, thereby improving the photoelectric conversion efficiency of solar cells.

[0073] In some embodiments, the chlorine element in the perovskite layer exists in the form of chloride ions;

[0074] Optionally, the solar cell further includes a first transport layer stacked with the perovskite layer, the first transport layer including chlorine element, the chlorine element in the first transport layer existing in the form of chloride ions.

[0075] Chlorine in the perovskite layer exists in the form of chloride ions, which facilitates the interaction between chlorine and perovskite and passivates defects in the perovskite layer.

[0076] Furthermore, the chlorine element in the first transport layer exists in the form of chloride ions, which is beneficial for passivating the interface between the first transport layer and the perovskite layer, improving the energy level matching between the first transport layer and the perovskite layer, enhancing their compatibility and the stability of the charge transport interface, thereby helping to better improve photoelectric conversion efficiency and long-term stability.

[0077] In some embodiments, the solar cell is a multi-junction solar cell, the multi-junction solar cell including a first cell unit, the first cell unit including the perovskite layer;

[0078] Optionally, the first battery cell further includes a first transport layer stacked with the perovskite layer.

[0079] The aforementioned perovskite layer can be incorporated into multi-junction solar cells to improve the photoelectric conversion efficiency, long-term stability, and device stability of multi-junction solar cells.

[0080] 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.

[0081] Multi-junction solar cells offer advantages such as improved utilization of incident light, while also maintaining high photoelectric conversion efficiency, long-term stability, and high device stability. Multi-junction solar cells can be monolithically integrated tandem solar cells or mechanically tandem solar cells, offering flexibility and a wide range of applications.

[0082] 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.

[0083] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0084] In some embodiments, the multi-junction solar cell includes a first electrode, a first transport layer, 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 first transport layer away from the perovskite layer, and the second electrode is located on the side of the second light-absorbing layer away from the carrier recombination layer or tunneling layer.

[0085] In this way, the two cells in a multi-junction solar cell are connected by an interconnect layer to achieve current matching between the two cells. The size is relatively smaller, and it can absorb light of different wavelengths, thus broadening the absorption spectrum range of the multi-junction solar cell and improving its photoelectric conversion efficiency and long-term stability.

[0086] In some embodiments, the multi-junction solar cell includes a first electrode, a first transport layer, 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 along the thickness direction of 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 first transport layer away from the perovskite layer, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode.

[0087] In this way, multi-junction solar cells form mechanically stacked cells. The two cell units are isolated by an insulating layer so that the charge carriers do not conduct directly and there is no need for current matching between them. At the same time, each cell unit is provided with its own positive and negative terminals to lead out current, which allows for flexible adjustment of the circuit.

[0088] Thirdly, this application provides a method for preparing a solar cell, comprising the following steps:

[0089] A first solution containing a first metal chloride is coated to form a first wet film. After a first drying and a first annealing, a perovskite precursor solution containing non-chloride monovalent anions is coated to form a perovskite precursor wet film. A second drying and a second annealing are then performed to form a perovskite layer.

[0090] The non-chlorinated monovalent anion is selected from the group consisting of non-chlorinated halide anions and pseudohalogen anions.

[0091] The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%;

[0092] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0093] The first relative concentration of chlorine in the first region is greater than the first relative concentration of chlorine in the second region.

[0094] Coating a first solution containing a first metal chloride into a first wet film can introduce chlorine into the perovskite layer and regulate the distribution of chlorine, promoting the effective enrichment of chlorine on the first surface. At the same time, a small amount of chlorine can migrate into the perovskite phase, making the first relative concentration of chlorine in the first region greater than the first relative concentration of chlorine in the second region.

[0095] Furthermore, non-chlorine monovalent anions, as one of the main components of the perovskite layer, have a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the defined first relative concentration of chlorine can characterize the chlorine content distribution in the perovskite layer. By introducing chlorine into the perovskite layer, on the one hand, chlorine near the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, and form a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase (such as in the second region) can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, by controlling the chlorine content in the perovskite layer within the above range, it is beneficial to reduce perovskite defects while taking into account the crystal quality and resistivity of the perovskite layer, thereby improving the performance of solar cells. This invention improves the photoelectric conversion efficiency and long-term stability of the solar cell. Simultaneously, by controlling the first relative concentration of chlorine in the first region to be greater than that in the second region, the chlorine concentration near the perovskite layer interface can be controlled to be greater than that in the middle of the perovskite bulk phase. This ensures that the chlorine concentration in the corresponding region matches the number of defects in that region, which is beneficial for effectively passivating defects in various regions of the perovskite layer (such as near the surface and in the middle of the bulk phase), improving the uniformity of the overall perovskite layer structure, while also considering the overall amount of chlorine used. In other words, a smaller amount of chlorine is needed to achieve the goals of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality. Therefore, this application can effectively reduce perovskite defects while maintaining the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0096] Fourthly, this application provides a method for preparing a solar cell, comprising the following steps:

[0097] A first solution containing a first metal chloride is coated to form a first wet film. After a first drying and a first annealing, a perovskite precursor solution containing non-chloride monovalent anions is coated to form a perovskite precursor wet film. A second drying and a second annealing are then performed to form a perovskite layer.

[0098] The non-chlorinated monovalent anion is selected from the group consisting of non-chlorinated halide anions and pseudohalogen anions.

[0099] The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%;

[0100] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0101] The first percentage of chlorine is defined as the ratio of the amount of chlorine in a preset region to the total amount of chlorine in the perovskite layer. The first percentage of chlorine in the first region is greater than the first percentage of chlorine in the second region.

[0102] Coating a first solution containing a first metal chloride into a first wet film can introduce chlorine into the perovskite layer and regulate the distribution of chlorine, promoting the effective enrichment of chlorine on the first surface. At the same time, a small amount of chlorine can migrate into the perovskite phase, making the first molar proportion of chlorine in the first region greater than that in the second region.

[0103] As one of the main components of the perovskite layer, the non-chlorine monovalent anion has a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the first relative concentration of chlorine can characterize the content distribution of chlorine in the perovskite layer. By introducing chlorine into the perovskite layer, on the one hand, near-surface chlorine can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, controlling the chlorine content in the perovskite layer within the above-mentioned range is beneficial for reducing perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell. At the same time, by controlling the chlorine content in the first region to be greater than that in the second region, the chlorine content in the corresponding region is matched with the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as near-surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, while taking into account the overall amount of chlorine used, that is, the purpose of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality can be achieved with a smaller amount of chlorine. Therefore, this application can effectively reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0104] In some embodiments, the perovskite precursor solution containing non-chlorine monovalent anions further includes a second metal chloride;

[0105] Optionally, the second metal chloride includes PbCl2;

[0106] Optionally, the molar percentage of chlorine in the second metal chloride relative to the non-chlorine monovalent anion is 0.05% to 9%.

[0107] The perovskite precursor solution containing non-chlorine monovalent anions facilitates the introduction of chlorine into the perovskite bulk phase. Simultaneously, due to the large radius of chlorine, during the annealing and ripening process of the perovskite material, as the solvent evaporates upwards from the system, chlorine is squeezed out of the bulk lattice and enriched on the second surface. This results in a higher chlorine content in the third region compared to the second region, which is beneficial for the formation of a quasi-two-dimensional thin film between chlorine and the perovskite material. This reduces perovskite bulk defects, passivates perovskite grain boundaries, increases open-circuit voltage, and further improves the photoelectric conversion efficiency and long-term stability of the solar cell.

[0108] Therefore, by coating the surface of the first transport layer with a first solution containing a first metal chloride, and then preparing the perovskite layer using a perovskite precursor solution containing non-chlorine monovalent anions, the distribution of chlorine in the first, second, and third regions of the perovskite layer can be effectively regulated. This allows chlorine to be effectively enriched in the first and third regions of the perovskite layer, while its content is lower in the second region. This effectively reduces perovskite defects and balances the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0109] Furthermore, PbCl2 has low solubility and readily accumulates on the surface of the perovskite layer, forming a defined perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell. Controlling the molar percentage of chlorine relative to non-chlorine monovalent anions in the second metal chloride within the aforementioned range is beneficial for ensuring that the chlorine content in the third region is greater than that in the second region. This facilitates the formation of a quasi-two-dimensional thin film between chlorine and the perovskite material, reducing perovskite bulk defects, passivating perovskite grain boundaries, and increasing open-circuit voltage. Simultaneously, it allows for effective regulation of the chlorine distribution in the first, second, and third regions of the perovskite layer, resulting in effective chlorine accumulation in the first and third regions while maintaining a lower content in the second region. This effectively reduces perovskite defects while balancing perovskite crystal quality and resistivity, ultimately improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0110] In some embodiments, the first metal chloride comprises PbCl2. PbCl2 has low solubility and readily precipitates competitively on the first surface of the perovskite layer, accumulating on the surface of the perovskite layer to form the defined perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0111] In some embodiments, the molar percentage of chlorine in the first metal chloride relative to the non-chlorine monovalent anion is 0.001% to 0.05%, and optionally 0.001% to 0.02%.

[0112] By controlling the molar percentage of chlorine relative to non-chlorine monovalent anions in the first metal chloride within the aforementioned range, the distribution of chlorine can be adjusted, promoting effective enrichment of chlorine on the first surface. Simultaneously, a small amount of chlorine can migrate into the perovskite bulk phase, making the chlorine content in the first region greater than that in the second region. This is beneficial for fully passivating defects in various regions of the perovskite layer (such as near the surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, and simultaneously maintaining the conductivity of the first region, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0113] In some embodiments, the second annealing includes: performing gradient annealing sequentially at temperatures T1 and T2, where temperature T1 > temperature T2;

[0114] Optionally, temperature T1 is 150℃~170℃, and temperature T2 is 100℃~120℃;

[0115] Optionally, the annealing time at temperature T1 is 2 min to 5 min; the annealing temperature at temperature T2 is 5 min to 15 min.

[0116] Annealing at temperature T1 promotes chlorine migration and perovskite nucleation; then annealing at temperature T2 promotes perovskite grain growth and reduces the adverse effects of high temperature on the perovskite matrix, thereby improving the perovskite crystal quality and enhancing the photoelectric conversion efficiency and long-term stability of solar cells.

[0117] Fifthly, this application provides a photovoltaic module, including at least one of the solar cells described in the first or second aspect and the solar cells prepared by the preparation method described in the third or fourth aspect. The above-mentioned photovoltaic module has improved photoelectric conversion efficiency and long-term stability.

[0118] In a sixth aspect, this application provides an electrical device comprising at least one of the solar cells described in the first or second aspect and the solar cells prepared by the preparation methods described in the third or fourth aspect.

[0119] The aforementioned electrical devices have improved photoelectric conversion efficiency and long-term stability.

[0120] In a seventh aspect, this application provides a power generation device, including at least one of the solar cells described in the first or second aspect and the solar cells prepared by the preparation method described in the third or fourth aspect.

[0121] The aforementioned power generation device has improved photoelectric conversion efficiency and long-term stability. Attached Figure Description

[0122] 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:

[0123] Figure 1 This is a schematic diagram of the perovskite layer of a solar cell according to an embodiment of the present application along the thickness direction, including the perovskite layer; the perovskite layer includes a first region, a second region, a first surface and a second surface; the first surface is the light-incident side;

[0124] Figure 2 This is a schematic diagram of the perovskite layer of a solar cell according to an embodiment of the present application along the thickness direction, including the perovskite layer; the perovskite layer includes a first region, a second region, a third region, a fourth region, a fifth region, a first surface and a second surface; the first surface is the light-incident side;

[0125] Figure 3 A schematic diagram of a solar cell according to an embodiment of this application; including a substrate layer, a first electrode, a first transport layer, a perovskite layer, a second transport layer, and a second electrode; the first electrode is the light-incident side electrode;

[0126] 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;

[0127] Figure 5 These are the qualitative analysis results of the TOF-SIMs of the solar cell module of Embodiment 1 of this application;

[0128] Figure 6 This is a graph showing the first relative concentration of chlorine in the perovskite layer of Example 1 of this application as a function of test time.

[0129] Figure 7 This is a graph showing the relationship between the first molar percentage of chlorine in the perovskite layer and the test time in Example 1 of this application.

[0130] Figure 8 This is a graph showing the relationship between the second substance's molar percentage of chlorine in the hole transport layer and the test time in Example 1 of this application.

[0131] Figure 9 This is a graph showing the second relative concentration of chlorine in the hole transport layer as a function of test time in Example 1 of this application.

[0132] Explanation of reference numerals in the attached figures: 100 is a solar cell; 110 is a substrate layer; 120 is a first electrode; 130 is a first transport layer; 140 is a perovskite layer; 150 is a second transport layer; 160 is a second electrode; P1 is a first channel region; P2 is a second channel region; P3 is a third channel region; 20 is an electrical device; 1401 is a first region; 1402 is a second region; 1403 is a third region; 1404 is a fourth region; 1405 is a fifth region; 1406 is a first surface; 1407 is a second surface.

[0133] It should be noted that, Figure 1-2 The dashed lines within the perovskite layer only indicate the positions of the first to fifth regions 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 1-3 The middle arrow indicates the incident light side; Z indicates the thickness direction of the perovskite layer. Detailed Implementation

[0134] 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.

[0135] 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.

[0136] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0137] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0138] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if a 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 it is mentioned that 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.

[0139] 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.

[0140] 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).

[0141] 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.

[0142] 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.

[0143] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," "fifth aspect," etc., and the terms "first," "second," "third," "fourth," "fifth," "sixth," "seventh," "eighth," etc., 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. Moreover, "first," "second," "third," "fourth," "fifth," "sixth," "seventh," "eighth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0144] 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".

[0145] 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.

[0146] In some embodiments of this application, the electron transport layer is capable of extracting and transporting electrons and blocking the passage of free holes.

[0147] In some embodiments of this application, the hole transport layer is capable of extracting and transporting holes and blocking the passage of free electrons.

[0148] In this application, unless otherwise specified, "charge carrier" can be an electron or a hole. "Carrier pair" refers to an electron-hole pair.

[0149] 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".

[0150] In this application, molar percentage refers to the proportion of an element or ion in a specific film layer or region of a solar cell relative to a specific ion (such as element X1) or its relative integrated count intensity. For example, the molar percentage of chlorine relative to element X1 is obtained by analyzing the proportion of chloride ions relative to element X1 or its integrated count intensity. This can be determined using a dual-mode time-of-flight secondary ion mass spectrometry (TOF-SIMs) cross-sectional imaging and depth profiling, with characteristic secondary ions serving as fingerprints. Furthermore, by statistically analyzing the atomic number or count intensity of elements or ions in different regions, the total atomic number and total count intensity of elements or ions within a specific range can be obtained, and the average molar percentage within that range can be calculated, which is the relative concentration.

[0151] It should be noted that when TOF-SIMs etch different film layers, the etching rate of different film layers varies, resulting in differences in depth profile time. By combining the scanning 3D imaging, the film layer to which each secondary ion flight time (x-axis) belongs can be determined. Based on this, the distribution of specific ions can be analyzed qualitatively or quantitatively.

[0152] The content of elements or ions in the entire structure, such as the perovskite layer or the first transport layer, can also be determined by X-ray fluorescence (XRF). The testing principle is as follows: when high-energy X-rays irradiate the sample, they excite the inner-shell electrons of the sample atoms. The outer-shell electrons then jump to fill the inner-shell vacancies and release secondary X-rays of specific energy (corresponding to the element type), i.e., X-ray fluorescence. By collecting and analyzing the energy and wavelength of these fluorescences, qualitative and quantitative analysis of the sample can be performed. Specifically, an X-ray fluorescence spectrometer (XRF) equipped with a capillary focusing optical system can be used for testing, and corresponding standards can be selected for calibration according to the elements or ions contained. For example, pure Ni blocks can be used for Ni calibration, SnO2:F thin film standards can be used for FTO calibration, and FAPbI3 single crystal wafers, FAPbBr3 single crystal wafers, and FAPbCl3 single crystal wafers can be used for Pb, I, Br, and Cl element calibration. Layered samples were tested in a vacuum environment. An Rh target was used to test the tube voltage / current, the spot size was limited to 50 μm, and the single-point detection time was set to 300 s, repeated three times. Multi-region testing was repeated in the same manner. After testing, the instrument automatically interpreted the spectrum, identified each characteristic peak, subtracted the background, and automatically output a percentage list of results based on the target curve.

[0153] In this application, the percentage of a specific element (such as chlorine, nickel, etc.) in a specific region refers to the percentage of the specific element in a specific region relative to the total amount of that element in the structural layer containing that specific region. That is, the percentage is calculated by taking the total amount of that element in the structural layer as 100%. For example, based on the total amount of chlorine in the hole transport layer, the percentage of chlorine in the first region = (amount of chlorine in the first region / total amount of chlorine in the hole transport layer) × 100%.

[0154] In this application, the average molar volume concentration of chlorine refers to the amount of chlorine per unit volume, which is obtained by dividing the number of moles of chlorine in the measurement area by the total volume of the measurement area, and is expressed in mmol / cm³. 3 .

[0155] It should be noted that the aforementioned molar percentages, the first relative concentration of chlorine, the second relative concentration of chlorine, the first molar percentage of chlorine, the second molar percentage of chlorine, and the third molar percentage of nickel can be obtained by analyzing the entire structural layer or characteristic region (when the device is small, the testing method includes the entire region), or by analyzing a local area of ​​the structural layer or characteristic region (usually referring to the effective measurement area, when the device is large). For example, through stratified simple random sampling, different test areas within the same depth layer are selected for testing, and then the results within the same depth layer or specific area are calculated based on the statistical results to ensure that the sampling is representative. Sampling methods, data processing, and statistical judgments can refer to "General Principles and Statistical Principles for Standard Material Value Determination" (JJF1343-2012).

[0156] In this application, the thickness direction of the perovskite layer is designated as the Z direction. Typically, the first and second surfaces of the perovskite layer are perpendicular or approximately perpendicular to the Z direction. Further, the direction from the first surface to the second surface in the thickness direction of the perovskite layer is designated as the Z1 direction; the direction from the second surface to the first surface in the thickness direction of the perovskite layer is designated as the Z2 direction.

[0157] In this application, "overall downward trend" or "overall upward trend" means that the first relative concentration of chlorine, the second relative concentration of chlorine, the proportion of the first amount of chlorine, or the proportion of the amount of chlorine can fluctuate to a certain extent. This does not exclude the occurrence of changes in local areas that are opposite to the overall trend. As long as the macro envelope of the concentration-depth curve (such as the curve obtained by 5-point moving average, spline fitting, or least squares linear regression) shows a decrease or increase, it meets the description.

[0158] Solar cells are devices that utilize photoelectric conversion mechanisms to convert light into electricity. With their advantages such as high conversion efficiency, high response speed, long lifespan, low energy consumption, small size, and environmental friendliness, they have shown enormous development potential in the new energy field. Semiconductor materials are the core of photoelectric conversion in solar cells, and perovskite materials, with their tunable bandgap, high defect tolerance, and low-temperature solution film formation capabilities, are widely used as semiconductor materials in solar cells.

[0159] As a core component of solar cells, the quality and defect state of the perovskite layer have a significant impact on the performance of these cells. Studies have found that dangling bonds and vacancies at the surface / grain boundaries of perovskite materials induce high concentrations of deep-level traps, becoming the main non-radiative recombination centers; while shallow-level defects in the bulk phase, although exhibiting lower recombination activity, provide pathways for ion migration. The combined effect of these two types of defects limits the photoelectric conversion efficiency and long-term stability of perovskite solar cells.

[0160] Based on this, this application provides a solar cell with improved photoelectric conversion efficiency and long-term stability, a method for preparing the same, and corresponding photovoltaic devices, electrical appliances, and power generation devices.

[0161] In some embodiments of the first aspect of this application, a solar cell is provided, including a perovskite layer comprising non-chlorine monovalent anions selected from a group consisting of non-chlorine halide anions and pseudohalogen anions; the perovskite layer further comprising chlorine; the molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anions in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%; the perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the light-incident side; the thickness of the perovskite layer is denoted as H; a first region with a thickness of 5 nm to 10 nm extends 20 nm from the first surface along the thickness direction toward the interior of the perovskite layer; a second region with a thickness of 5 nm to 10 nm extends 10 nm from H / 2 of the perovskite layer along the thickness direction toward the first surface and the second surface, respectively; the first relative concentration of chlorine in the first region is greater than the first relative concentration of chlorine in the second region.

[0162] As one of the main components of the perovskite layer, the non-chlorine monovalent anion has a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the first relative concentration of chlorine can characterize the content distribution of chlorine in the perovskite layer.

[0163] By introducing chlorine into the perovskite layer, on the one hand, chlorine near the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, and form a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase (such as in the second region) can reduce shallow energy level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, by controlling the chlorine content in the perovskite layer within the above-mentioned range, it is beneficial to reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0164] Furthermore, since light arrives first on the incident side, the lattice of the first surface of the perovskite layer (i.e., the side closest to the incident light) is suddenly interrupted, generating a large number of uncoordinated dangling bonds and vacancies, further exacerbating surface defects. This results in significantly greater interface defects in the first region (the near-surface region close to the incident light) compared to the second region (the central region of the perovskite bulk phase). By controlling the first relative concentration of chlorine in the first region to be greater than that in the second region, it is possible to control the chlorine concentration near the perovskite interface to be greater than that in the central perovskite bulk phase. This ensures that the chlorine concentration in the corresponding region matches the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as the near-surface and the central bulk phase), improving the overall structural uniformity of the perovskite layer, while also taking into account the overall amount of chlorine used. In other words, a smaller amount of chlorine can achieve the goals of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality. By passivating perovskite defects and improving the crystal quality of the perovskite layer, ion migration can be suppressed, water and oxygen erosion can be blocked, non-radiative recombination can be reduced, and the long-term stability of solar cells can be improved. Therefore, this application can effectively reduce perovskite defects while taking into account the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0165] like Figure 1 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 region 1402, a first surface 1406, and a second surface 1407, with the arrow indicating the light-incident side, and the first surface 1406 being the light-incident side surface. The first region 1401 is close to the first surface 1406 and represents a specific region near or on the surface of the perovskite layer, which may or may not include the first surface 1406. The second region 1402 is close to the middle of the perovskite layer and represents a representative region in the bulk phase of the perovskite layer.

[0166] In some embodiments of this application, the first relative concentration of chlorine in the perovskite layer can be 0.004% to 5.17%, and more preferably 0.08% to 4%. Specifically, the first relative concentration of chlorine in the perovskite layer can be 0.001%, 0.002%, 0.003%, 0.004%, 0.008%, 0.1%, 0.17%, 0.3%, 0.5%, 1%, 2%, 3%, 4%, 5%, 5.17%, 6%, etc. Controlling the first relative concentration of chlorine in the perovskite layer within the above range can effectively reduce perovskite defects and better balance the crystal quality and resistivity of the perovskite layer, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0167] In this application, the perovskite layer includes a perovskite material. The perovskite material in the perovskite layer is referred to as the 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). Typically, 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 lattice structure. The first cation can be denoted as [A], the second cation as [M], and the anion as [X1].

[0168] 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 structure.

[0169] 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 structure.

[0170] 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 The ionic radius of the ion at the X1 position is given.

[0171] 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).

[0172] In some embodiments of this application, the perovskite layer includes a first perovskite material, which comprises non-chlorine monovalent anions. Non-chlorine monovalent anions are beneficial for achieving charge balance and maintaining crystal structure stability, thereby improving the photoelectric conversion efficiency of the solar cell.

[0173] In some embodiments of this application, the first perovskite material has the following general formula:

[0174] [A] a [M] b [X1] c ;

[0175] A includes a first cation, M includes a second cation, and X1 includes at least one of a non-chlorine halide ion and a pseudohalogen ion.

[0176] a is an integer from 1 to 6, b is an integer from 1 to 6, and c is an integer from 1 to 18.

[0177] 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 AB[X1]3 or A2CD[X1]6; 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 X1 is a monovalent anion.

[0178] 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 X1-site ions.

[0179] 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.

[0180] 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.

[0181] 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 of methylamino, ethylamino, propylamino, butylamino, pentamino, hexamino, formamidinyl, and imidazolyl.

[0182] 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.

[0183] 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, C 1-20 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 1-3Alkyl, 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] In some embodiments of this application, the molar percentage of bromide anions in the monovalent anions of the perovskite material is 0 to 1.0.

[0191] 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.

[0192] Without limitation, in perovskite-type metal halides, B can be an inorganic cation.

[0193] 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.

[0194] 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.

[0195] In perovskite-type metal halides, X1 can be an inorganic anion, an organic anion, or a mixture of organic and inorganic anions.

[0196] In some embodiments of this application, in the perovskite-type metal halide, X1 is a halide anion; optionally, X1 includes F. - Cl - ,Br - and I - One or more of them, and optionally, X1 includes Cl - ,Br - and I - One or more of the following. In some embodiments, X1 in the perovskite metal halide can be I. - ,Br - and Cl - One or more of them.

[0197] Without limitation, X1 in perovskite-type metal halides may include I - ,Br - One or two of them. X1 can be I - ,Br - Or a combination thereof. In some embodiments, X1 is I. - .

[0198] 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). + ).

[0199] In a non-limiting sense, in perovskite metal halides, D can be an inorganic cation, an organic cation, or a mixed organic-inorganic cation.

[0200] 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.

[0201] It is understood that the first perovskite material in the aforementioned perovskite layer can be selected from Cs. x1 FA 1-x1 Pb[X1]3、Cs x1 MA 1-x1 Pb[X1]3、Cs m FA n MA 1-m-n Pb[X1]3, CsPb[X1]3, MAPb[X1]3, FAPb[X1]3, Cs x1 FA 1-x1 Pb x2 Sn 1-x2 [X1]3、Cs x1 FA 1-x1 Pb x2 Sn 1-x2 [X1]3、Cs m FA n MA 1-m-n Pb x2 Sn 1-x2 [X1]3、CsPb x2 Sn 1-x2 [X1]3、MAPb x2 Sn 1-x2 [X1]3 and FAPb x2 Sn 1-x2 One or more of [X1]3, wherein 0 < x1 < 1, 0 < x2 < 1, 0 < m < 1, 0 < n < 1.

[0202] As an example, the first perovskite material includes CH8I3N2Pb (FAPbI3), Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3, CsPbBr3, CsPbI3, Cs 0.05 FA 0.95 PbI3 and MA 0.2 FA 0.8 One or more of PbI3.

[0203] 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 1000 nm, etc.

[0204] In some embodiments of this application, the first relative concentration of chlorine in the first region is 0.003% to 1.5%, optionally 0.05% to 1.5%, such as 0.003%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.5%, 1.0%, 1.2%, 1.4%, 1.5%, etc. By controlling the first relative concentration of chlorine in the first region within the aforementioned range, chlorine more effectively passivates defects near the interface of the perovskite layer close to the first surface, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0205] In some embodiments of this application, the first relative concentration of chlorine in the second region is 0.00001% to 0.05%, which may be 0.0005% to 0.05%, such as 0.00001%, 0.0001%, 0.0003%, 0.0005%, 0.0008%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc.

[0206] By controlling the first relative concentration of chlorine in the second region within the aforementioned range, the chlorine can more fully passivate the defects in the bulk phase of the perovskite layer, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0207] In some embodiments of this application, the first relative concentration of chlorine in the first region is 0.003% to 1.5%, optionally 0.05% to 1.5%, such as 0.003%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.5%, 1.0%, 1.2%, 1.4%, 1.5%, etc. The first relative concentration of chlorine in the second region is 0.00001% to 0.05%, optionally 0.0005% to 0.05%, such as 0.00001%, 0.0001%, 0.0003%, 0.0005%, 0.0008%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc.

[0208] Controlling the concentration of chlorine in one or more of the first relative concentrations in the first and second regions within the aforementioned range is beneficial for simultaneously and sufficiently passivating defects near the interface close to the first surface and in the bulk phase of the perovskite layer. It also improves the uniformity of the overall structure of the perovskite layer, thereby enhancing the photoelectric conversion efficiency and long-term stability of the solar cell.

[0209] In some embodiments, the ratio of the first relative concentration of chlorine in the first region to the first relative concentration in the second region is (29~105):1, optionally (32~88):1, for example 29:1, 30:1, 31:1, 32:1, 36:1, 40:1, 50:1, 60:1, 70:1, 80:1, 88:1, 90:1, 95:1, 100:1, 105:1, etc. Controlling the ratio of the first relative concentration of chlorine in the first region to the first relative concentration in the second region within the above range is beneficial for enriching chlorine in the first region and reducing the chlorine content in the perovskite layer bulk phase, better matching the appropriate chlorine concentration required for passivating defects in different regions, and better improving the uniformity of the overall structure of the perovskite layer, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0210] The intrinsic point defects of perovskite have a higher formation energy in the bulk phase than at the surface or grain boundaries. Therefore, the interface near the second surface in the perovskite layer is more prone to having more defects than the bulk phase of the perovskite layer.

[0211] In some embodiments of this application, a region with a thickness of 5nm to 10nm exists within a region extending 20nm from the second surface along the thickness direction of the perovskite layer into the interior of the perovskite layer, referred to as the third region; the first relative concentration of chlorine in the third region is greater than the first relative concentration of chlorine in the second region. By controlling the concentration of chlorine in the third region to be greater than that in the second region, it is beneficial, on the one hand, to allow chlorine near the interface of the second surface in the perovskite layer (such as in the second region) to form a quasi-two-dimensional thin film with the perovskite material, reducing defects near the interface of the second surface in the perovskite, passivating the perovskite grain boundaries, and increasing the open-circuit voltage; on the other hand, it is beneficial, as chlorine can simultaneously and sufficiently passivate defects near the second surface and in the bulk phase of the perovskite layer, which is beneficial to improving the uniformity of the overall structure of the perovskite layer; thereby, it is beneficial to improve the photoelectric conversion efficiency and long-term stability of the solar cell.

[0212] 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 region 1402, a third region 1403, a first surface 1406, and a second surface 1407. The arrows indicate the light-incident side. The first region 1401 is close to the first surface 1406, which is the light-incident side surface. The third region 1403 is close to the second surface 1407, and may or may not include the second surface 1407. The first region 1401 and the third region 1403 represent specific regions near or on the surface of the perovskite layer, while the second region 1402 is close to the middle of the perovskite layer and represents a representative region in the bulk phase of the perovskite layer.

[0213] Understandably, a first region with a thickness of 5nm to 10nm exists within a region extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer. This refers to any region of 5nm to 10nm within the region extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer. For example, a region extending 5nm to 10nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer, or a region extending 5nm to 5nm+(5~10)nm (e.g., 10nm to 20nm) from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer. The understanding of the third region is similar to that of the first region. There exists a second region with a thickness of 5nm to 10nm within a region extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively. This includes any 5nm to 10nm range extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, for example, extending from the first surface into the perovskite layer from 1 / 2×H-10nm to (1 / 2×H-10nm)+(5~10)nm, or for example, extending from the first surface into the perovskite layer from 1 / 2×H to 1 / 2×H+(5~10)nm.

[0214] In some embodiments of this application, the first relative concentration of chlorine in the third region is less than the first relative concentration of chlorine in the first region. Therefore, on the one hand, chlorine near the first surface of the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing bulk defects in the perovskite and passivating perovskite grain boundaries. On the other hand, chlorine near the interface of the second surface in the perovskite layer (such as in the third region) forms a quasi-two-dimensional thin film with the perovskite material, reducing defects near the interface of the second surface in the perovskite, passivating perovskite grain boundaries, and increasing the open-circuit voltage. By controlling the first relative concentration of chlorine in the third region to be less than the first relative concentration of chlorine in the first region, it is possible to control the chlorine concentration near the first surface of the perovskite layer to be greater than the chlorine concentration near the second surface, so that the chlorine concentration in the corresponding region matches the number of defects in that region. This is beneficial for chlorine to simultaneously and sufficiently passivate defects near the interface of the first surface and the second surface in the perovskite layer, and to better improve the uniformity of the overall structure of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0215] In some embodiments of this application, the first relative concentration of chlorine in the third region is 0.0005% to 0.6%, optionally 0.01% to 0.5%, such as 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc. Controlling the first relative concentration of chlorine in the third region within the above range is beneficial for fully passivating defects near the interface close to the second surface (such as in the third region), while also better maintaining the uniformity of the overall perovskite layer structure, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0216] In some embodiments of this application, the first relative concentration of chlorine in the third region is less than the first relative concentration of chlorine in the first region; the first relative concentration of chlorine in the third region is 0.0005% to 0.6%, optionally 0.01% to 0.5%, for example 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc. By controlling the first relative concentration of chlorine in the third region to be less than the first relative concentration of chlorine in the first region, it is possible to control the concentration of chlorine near the first surface of the perovskite layer to be greater than the concentration of chlorine near the second surface, so that the concentration of chlorine in the corresponding region matches the number of defects in that region. This is beneficial for chlorine to simultaneously and sufficiently passivate defects near the interface close to the first surface and near the second surface in the perovskite layer, and to better improve the uniformity of the overall structure of the perovskite layer. Controlling the first relative concentration of chlorine in the third region within the above range is beneficial for sufficiently passivating defects near the interface close to the second surface (such as in the third region), while also better maintaining the uniformity of the overall structure of the perovskite layer. This will improve the photoelectric conversion efficiency and long-term stability of solar cells.

[0217] In some embodiments, the region extending d1 from the first surface toward the interior of the perovskite layer along the thickness direction of the perovskite layer is referred to as the fourth region, where 1 / 2×H-10nm≤d1≤1 / 2×H+10nm; the direction from the first surface to the second surface along the thickness direction from near the first surface to the side away from the first surface is referred to as the Z1 direction, and the first relative concentration of chlorine in the fourth region generally decreases in the Z1 direction.

[0218] The intrinsic point defects of perovskite form at higher energy levels in the bulk phase than at the surface or grain boundaries. Therefore, the defect density in the fourth region generally decreases from the first surface along the thickness direction to the side away from the first surface. Controlling the distribution of chlorine in the fourth region to follow this trend helps to match the chlorine concentration in the corresponding region with the number of defects in that region. This allows chlorine to simultaneously and sufficiently passivate the defects in the fourth region of the perovskite layer and improves the overall uniformity of the perovskite layer structure. Consequently, this is beneficial for improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0219] In some embodiments, the region extending d2 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the fifth region, where 1 / 2×H-10nm≤d2≤1 / 2×H+10nm; the direction from the first surface to the second surface along the thickness direction of the perovskite layer from the side near the first surface is denoted as the Z1 direction, and the first relative concentration of chlorine in the fifth region generally shows an increasing trend in the Z1 direction.

[0220] The intrinsic point defects of perovskite form at higher energy levels in the bulk phase than at the surface or grain boundaries. Therefore, the defect density in the fifth region generally increases along the direction from the first surface to the second surface. Controlling the distribution of chlorine in the fifth region to follow this trend helps to match the chlorine concentration in the corresponding region with the number of defects in that region. This facilitates the simultaneous and sufficient passivation of defects in the fifth region of the perovskite layer by chlorine, and improves the overall uniformity of the perovskite layer structure. Consequently, it helps to better improve the photoelectric conversion efficiency and long-term stability of solar cells.

[0221] It should be noted that the direction from the first surface to the second surface in the thickness direction of the perovskite layer is denoted as the Z1 direction. The first relative concentration of chlorine in the fourth and fifth regions lies in the Z1 direction, which can be determined by referring to the first relative concentration of chlorine versus test time graph. Specifically, it shows the first relative concentration of chlorine in regions corresponding to different depths, for example, in TOF-SIMs testing, the first relative concentration of chlorine in regions corresponding to different depths obtained as the test time changes. It is only used to illustrate the variation of the first relative concentration of chlorine with different depths. Figure 6 As shown.

[0222] like Figure 2As 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 region 1402, a third region 1403, a fourth region 1404, a fifth region 1405, a first surface 1406, and a second surface 1407. The arrows indicate the light-incident side. The first region 1401 is close to the first surface 1406 and is the light-incident side. The third region 1403 is close to the second surface 1407. The first and third regions represent specific regions near or on the surface of the perovskite layer. The second region 1402 is close to the middle of the perovskite layer. The fourth region 1404 is close to the first surface and is located between the first region 1401 and the second region 1402. The fifth region 1405 is close to the second surface 1407 and is located between the third region 1403 and the second region 1402. The second region 1402, the fourth region 1404, and the fifth region 1405 represent specific regions in the bulk phase of the perovskite layer.

[0223] In a second aspect, this application provides a solar cell including a perovskite layer, the perovskite layer including non-chlorine monovalent anions, the non-chlorine monovalent anions being selected from the group consisting of non-chlorine halide anions and pseudohalogen anions.

[0224] The perovskite layer also includes chlorine; the molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, 0 < M0 ≤ 6%;

[0225] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there is a second region with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0226] The first percentage of chlorine is defined as the ratio of the amount of chlorine in a preset region to the total amount of chlorine in the perovskite layer. The first percentage of chlorine in the first region is greater than that in the second region.

[0227] Non-chlorine monovalent anions, as one of the main components of the perovskite layer, have a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the defined first relative concentration of chlorine can characterize the content distribution of chlorine in the perovskite layer. On the light-incident side, since light arrives first, the lattice of the first surface of the perovskite layer (i.e., the side closest to the light-incident side) is suddenly interrupted, generating a large number of uncoordinated dangling bonds and vacancies, further aggravating its surface defects. This results in the interface defects in the first region (the near-surface region close to the light-incident side) being significantly greater than those in the second region (the central region of the perovskite layer bulk phase). By introducing chlorine into the perovskite layer, on the one hand, near-surface chlorine can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, controlling the chlorine content in the perovskite layer within the above-mentioned range is beneficial for reducing perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell. At the same time, by controlling the chlorine content in the first region to be greater than that in the second region, the chlorine content in the corresponding region is matched with the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as near-surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, while taking into account the overall amount of chlorine used, that is, the purpose of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality can be achieved with a smaller amount of chlorine. Therefore, this application can effectively reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0228] In some embodiments, the first substance content of chlorine in the first region is 6% to 15%, optionally 9% to 15%, such as 6%, 8%, 10%, 12%, 14%, 15%, etc. By controlling the first substance content of chlorine in the first region within the aforementioned range, chlorine more effectively passivates defects near the interface of the perovskite layer close to the first surface, while also better maintaining the uniformity of the overall structure of the perovskite layer, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0229] In some embodiments, the first molar percentage of chlorine in the second region is 0.3% to 2%, optionally 0.4% to 1%, such as 0.3%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, etc. By controlling the first molar percentage of chlorine in the second region within the aforementioned range, the chlorine can more fully passivate defects in the bulk phase of the perovskite layer, while also better maintaining the uniformity of the overall perovskite layer structure, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0230] In some embodiments, the ratio of the first amount of chlorine in the first region to the first amount of chlorine in the second region is (10~35):1, for example, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, 25:1, 30:1, 32:1, 34:1, 35:1, etc.

[0231] Controlling the ratio of the first molar proportion of chlorine in the first region to that in the second region within the above range is beneficial for enriching chlorine in the first region and reducing the chlorine content in the perovskite layer bulk phase. This allows for better matching of the appropriate chlorine concentration required to passivate defects in different regions, and better improvement of the overall uniformity of the perovskite layer structure. Consequently, it is beneficial for improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0232] The intrinsic point defects of perovskite have a higher formation energy in the bulk phase than at the surface or grain boundaries. Therefore, the interface near the second surface in the perovskite layer is more prone to having more defects than the bulk phase of the perovskite layer.

[0233] In some embodiments, a region with a thickness of 5nm to 10nm exists within a region extending 20nm from the second surface along the thickness direction of the perovskite layer into the interior of the perovskite layer, referred to as the third region; the first substance proportion of chlorine in the third region is greater than that in the second region. By controlling the first substance proportion of chlorine in the third region to be greater than that in the second region, it is beneficial, on the one hand, to enable chlorine near the interface of the second surface in the perovskite layer (such as in the second region) to form a quasi-two-dimensional thin film with the perovskite material, reducing defects near the interface of the second surface in the perovskite, passivating the perovskite grain boundaries, and increasing the open-circuit voltage; on the other hand, it is beneficial to enable chlorine to simultaneously and sufficiently passivate defects near the second surface and in the bulk phase of the perovskite layer, which is beneficial to improving the uniformity of the overall structure of the perovskite layer; thereby, it is beneficial to improve the photoelectric conversion efficiency and long-term stability of the solar cell.

[0234] In some embodiments, the first substance content of chlorine in the third region is 5% to 14%, optionally 5% to 10%, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, etc. Controlling the first substance content of chlorine in the third region within the above range is beneficial for fully passivating defects near the interface close to the second surface (such as in the third region), while also better maintaining the uniformity of the overall perovskite layer structure, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0235] In some embodiments, the first molar percentage of chlorine in the third region is less than that in the first region. The first region, as the near-light-receiving region, has a higher defect density than the third region. Thus, on the one hand, chlorine near the first surface of the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, and form a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine near the interface of the second surface in the perovskite layer (such as in the third region) forms a quasi-two-dimensional thin film with the perovskite material, reducing defects near the interface of the second surface in the perovskite, passivating perovskite grain boundaries, and increasing the open-circuit voltage. Meanwhile, by controlling the amount of the first substance in the third region to be less than the amount of the first substance in the first region, it is possible to control the chlorine concentration near the first surface of the perovskite layer to be greater than the chlorine concentration near the second surface. This allows the chlorine concentration in the corresponding region to match the number of defects in that region, which is beneficial for chlorine to simultaneously and fully passivate defects near the interface between the first and second surfaces in the perovskite layer. It also improves the uniformity of the overall structure of the perovskite layer, thereby helping to better improve the photoelectric conversion efficiency and long-term stability of the solar cell.

[0236] In some embodiments, a region extending d1 from the first surface into the perovskite layer along its thickness direction is designated as the fourth region, where 1 / 2×H-10nm ≤ d1 ≤ 1 / 2×H+10nm. The direction from the first surface to the second surface along the thickness direction of the perovskite layer is designated as the Z1 direction. The proportion of chlorine in the fourth region generally decreases along the Z1 direction. Since the formation energy of intrinsic point defects in the perovskite bulk phase is higher than that at the surface or grain boundaries, the defect density in the fourth region generally decreases from the first surface along the thickness direction to the side away from the first surface. Controlling the distribution of chlorine in the fourth region to follow this trend is beneficial for matching the chlorine concentration in the corresponding region with the number of defects in that region. This facilitates the simultaneous and sufficient passivation of defects in the fourth region of the perovskite layer by chlorine, and improves the overall uniformity of the perovskite layer structure, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0237] In some embodiments, the region extending d2 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is designated as the fifth region, where 1 / 2×H-10nm≤d2≤1 / 2×H+10nm. The direction from the first surface to the second surface in the thickness direction of the perovskite layer is designated as the Z1 direction, and the proportion of chlorine in the fifth region generally increases in the Z1 direction. Since the formation energy of intrinsic point defects in the perovskite in the bulk phase is higher than that at the surface or grain boundaries, the defect density in the fifth region generally increases from the side closest to the first surface along the thickness direction to the second surface. Controlling the distribution of chlorine in the fifth region to follow this trend is beneficial for matching the chlorine concentration in the corresponding region with the number of defects in that region. This facilitates the simultaneous and sufficient passivation of defects in the fifth region of the perovskite layer by chlorine, and improves the overall uniformity of the perovskite layer structure, thereby better improving the photoelectric conversion efficiency and long-term stability of the solar cell. Furthermore, by passivating perovskite defects and improving the crystal quality of the perovskite layer, ion migration can be suppressed, water and oxygen erosion can be blocked, non-radiative recombination can be reduced, and the long-term stability of solar cells can be improved.

[0238] It should be noted that the direction from the first surface to the second surface in the thickness direction of the perovskite layer is denoted as the Z1 direction. The proportion of chlorine in the first substance in the fourth and fifth regions lies in the Z1 direction, which can be determined by the relationship between the proportion of chlorine in the first substance and the test time. Specifically, it shows the proportion of chlorine in the first substance at different depths, for example, in TOF-SIMs testing, the proportion of chlorine in the first substance at different depths obtained as the test time changes. It is only used to illustrate the variation of the proportion of chlorine in the first substance with different depths. Figure 7 As shown.

[0239] In some embodiments, the average molar volume concentration of chlorine in the perovskite layer is 0.000001 mmol / cm³. 3 ~0.00001mmol / cm 3 For example, 0.000001 mmol / cm 3 0.000002 mmol / cm 3 0.000003 mmol / cm 3 0.000004 mmol / cm 3 0.000005 mmol / cm 3 0.000006 mmol / cm 3 0.000007 mmol / cm 3 0.000008 mmol / cm 30.000009 mmol / cm 3 0.00001 mmol / cm 3 wait.

[0240] By controlling the average molar volume concentration of the perovskite layer within the above range, it is beneficial to reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0241] In some embodiments of this application, the first transport layer includes chlorine. Introducing chlorine into the first transport layer helps passivate the interface between the first transport layer and the perovskite layer, improves the energy level matching between the two layers, enhances their compatibility and the stability of the charge transport interface, thereby contributing to better improvement of the photoelectric conversion efficiency and long-term stability of the solar cell.

[0242] In some embodiments of this application, the solar cell satisfies one or more of the following features:

[0243] (a1) The perovskite layer is contained in the inverse or formal structure of the solar cell;

[0244] (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.

[0245] The aforementioned implementation methods can be universally applied to solar cells with conventional or inverted structures, improving photoelectric conversion efficiency, long-term stability, 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.

[0246] 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.

[0247] 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).

[0248] 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).

[0249] 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).

[0250] 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.

[0251] 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.

[0252] 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.

[0253] In some embodiments of this application, the first transport layer is a hole transport layer.

[0254] In some embodiments of this application, the first transport layer comprises nickel oxide. Nickel oxide possesses excellent chemical and thermal stability, high energy level matching with the perovskite layer, low optical loss, good process compatibility, and low cost, which is beneficial for improving the photoelectric conversion efficiency of solar cells. Furthermore, when the first transport layer comprises nickel oxide, by controlling the enrichment of chlorine in a first region of the perovskite layer (e.g., by controlling the first relative concentration or the first molar percentage of the first substance in the first region to be higher than that in the second region), it is beneficial for passivating Ni through coordination. 3+ Suppress Ni 3+ Migration into the perovskite layer helps to leverage the aforementioned advantages of nickel oxide while also effectively reducing Ni content. 3+ The degradation of perovskite crystals improves the structural stability of the perovskite layer, which in turn helps to improve photoelectric conversion efficiency and long-term stability.

[0255] In some embodiments of this application, the direction from the second surface to the first surface in the thickness direction of the perovskite layer is denoted as the Z2 direction;

[0256] The proportion of the amount of chlorine in the preset region of the first transport layer relative to the total amount of chlorine in the first transport layer is denoted as the second proportion of chlorine; the proportion of the second proportion of chlorine in the first transport layer generally shows an upward trend in the Z2 direction.

[0257] At this point, it is beneficial to more effectively exert passivation and suppress Ni in the first transport layer. 3+ Migration helps to better reduce Ni migration into the perovskite layer. 3+ The content of these substances helps to improve photoelectric conversion efficiency and long-term stability. In addition, it can also help improve the long-term stability of solar cells.

[0258] It should be noted that the direction from the second surface to the first surface in the thickness direction of the perovskite layer is denoted as the Z2 direction. The proportion of chlorine in the second substance of the first transport layer in the Z2 direction can be determined by the relationship between the proportion of chlorine in the second substance and the test time. Specifically, it shows the proportion of chlorine in the second substance at different depths, for example, in TOF-SIMs testing, the proportion of chlorine in the second substance at different depths obtained as the test time changes. It is only used to illustrate the variation of the proportion of chlorine in the second substance with different depths. Figure 8 As shown.

[0259] In some embodiments of this application, the surface of the first transport layer facing away from the perovskite layer is designated as the third surface. Based on the total amount of chlorine in the first transport layer, the proportion of chlorine in the region extending 2nm to 3nm from the third surface toward the interior of the first transport layer (referred to as the sixth region) is 7% to 26%, for example, 7%, 9%, 10%, 15%, 20%, 25%, 26%, etc.; the proportion of chlorine in the region extending 2nm to 3nm from the first surface toward the interior of the first transport layer (referred to as the seventh region) is 6% to 16%, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%.

[0260] In some embodiments of this application, the molar percentage of chlorine relative to nickel in a predetermined region of the first transport layer is denoted as the second relative concentration of chlorine in that predetermined region. The second relative concentration of chlorine in the first transport layer is 15% to 40%, for example, 15%, 20%, 25%, 30%, 35%, 40%, etc. This helps to reduce the migration of Ni. 3+ The content of Ni is reduced, thereby lowering the Ni content. 3+ This reduces the adverse effects on the first perovskite material and further modulates the energy levels of the first transport layer and the perovskite layer, improving their compatibility and the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0261] 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.

[0262] In some embodiments of this application, the second transport layer is an electron transport layer. The provision of a second transport layer facilitates the extraction and transport of electrons and / or holes generated by photon excitation of the perovskite layer to the corresponding electrodes, thereby improving the photoelectric conversion performance of the solar cell.

[0263] 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.

[0264] In some embodiments of this application, the non-chlorine monovalent anion includes iodide ions. Iodide ions have a large radius, which can cause lattice expansion, which is beneficial for adjusting the band gap. At the same time, iodide ions are conducive to the formation of perovskite materials with symmetrical crystal phase structures, reducing local strain and defect density, and also helping to reduce the resistance of perovskite materials. Therefore, they can improve the photoelectric conversion efficiency and long-term stability of solar cells.

[0265] In some embodiments of this application, based on the total amount of non-chlorine monovalent anions in the perovskite layer, the proportion of iodide ions in the perovskite layer is 80.0% to 99.8%, for example, 80.0%, 82%, 85%, 90%, 95%, 97%, 98%, 99%, 99.8%, etc. Controlling the iodide ion content within the aforementioned range is beneficial for reducing perovskite defects, while also considering the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0266] In some embodiments of this application, the non-chlorine monovalent anion includes bromide ions; bromide ions have a smaller radius, which is beneficial for shrinking the crystal lattice, reducing the strain gradient, improving the uniformity of the crystal structure, and improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0267] In some embodiments of this application, the proportion of bromide ions in the perovskite layer, based on the total amount of non-chlorine monovalent anions in the perovskite layer, is 0.2% to 20%, for example, 0.2%, 0.5%, 1%, 5%, 10%, 15%, 17%, 19%, 20%, etc. Controlling the proportion of bromide ions in the perovskite layer within the above range is beneficial for shrinking the crystal lattice, reducing the strain gradient, improving the uniformity of the crystal structure, reducing phase separation, and having a narrower band gap, which is beneficial for improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0268] 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.

[0269] 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.

[0270] In this application, unless otherwise specified, "multi-junction solar cell" refers to a solar cell in which two or more sub-cells composed 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 units, each cell unit including at least one light-absorbing layer, and each light-absorbing layer has a different band gap.

[0271] 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.

[0272] In this application, unless otherwise specified, "battery cell" and "battery section" have the same meaning and can be used interchangeably.

[0273] In this application, unless otherwise specified, "light-absorbing layer" and "light-absorbing layer" have the same meaning and can be used interchangeably.

[0274] 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.

[0275] Multi-junction solar cells offer advantages such as improved utilization of incident light, while also maintaining high photoelectric conversion efficiency, long-term stability, and high device stability. Multi-junction solar cells can be monolithically integrated tandem solar cells or mechanically tandem solar cells, offering flexibility and a wide range of applications.

[0276] In some embodiments of this application, the first light-absorbing layer is the aforementioned perovskite layer.

[0277] The aforementioned perovskite layer can be incorporated into multi-junction solar cells to improve the photoelectric conversion efficiency, long-term stability, and device stability of multi-junction solar cells.

[0278] 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.

[0279] 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.

[0280] In some embodiments of this application, the interconnect layer includes a carrier recombination layer.

[0281] In some embodiments of this application, the interconnect layer includes a tunneling layer.

[0282] 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 and long-term stability of the multi-junction solar cell.

[0283] In some embodiments, the multijunction solar cell is a tandem solar cell.

[0284] 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 has a different band gap than the perovskite layer. 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 and long-term stability.

[0285] 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: second perovskite material, 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, organic active material, etc.

[0286] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0287] In some embodiments of this application, a carrier recombination layer or a tunneling layer is provided between the monolithically integrated battery cells.

[0288] In this application, unless otherwise specified, the "carrier recombination layer" is a structural layer in which electrons and holes transported from two different battery cells recombine, enabling the two battery cells to achieve ohmic connection and share the positive and negative electrodes.

[0289] In some embodiments of this application, a carrier recombination layer or tunneling layer is provided between battery cells connected in series.

[0290] 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.

[0291] In some embodiments of this application, a carrier recombination layer is provided between the first battery cell and the second battery cell.

[0292] 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.

[0293] In some embodiments of this application, an interconnection structure is provided between the first battery cell and the second battery cell.

[0294] In some embodiments of this application, a tunnel junction may be formed between the first battery cell and the second battery cell.

[0295] 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.

[0296] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a first transport layer, a perovskite layer, an interconnect layer, a light-absorbing layer, and a second electrode stacked together. The interconnect layer is located between the perovskite layer and the light-absorbing layer. The first electrode is located on the side of the first transport layer away from the perovskite layer, and the second electrode is located on the side of the light-absorbing layer away from the interconnect layer. Thus, two cell units in a 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 improved photoelectric conversion efficiency and long-term stability.

[0297] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a first transport layer, 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 first transport layer away from the perovskite layer, 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.

[0298] 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.

[0299] 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.

[0300] In some embodiments of this application, the tandem solar cell includes a first electrode, a first transport layer, a first light absorption layer, a carrier recombination layer, a second light absorption layer, and a second electrode. The first light absorption layer and the second light absorption layer are respectively disposed on both sides of the carrier recombination layer. The first electrode is located on the side of the first transport layer away from the perovskite layer, and the second electrode is located on the side of the second light absorption layer away from the carrier recombination layer.

[0301] In some embodiments of this application, the tandem solar cell includes a first electrode, a first transport layer, a first light absorption layer, a tunneling layer, a second light absorption layer, and a second electrode. The first light absorption layer and the second light absorption layer are respectively disposed on both sides of the tunneling layer. The first electrode is located on the side of the first transport layer away from the perovskite layer, and the second electrode is located on the side of the second light absorption layer away from the tunneling layer.

[0302] 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.

[0303] 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 and long-term stability 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.

[0304] In some embodiments, the second light-absorbing layer comprises one or more of the following compounds: 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, cadmium telluride, etc. These materials can absorb light of different wavelengths with the perovskite layer, thereby broadening the spectral range of light absorption in multi-junction solar cells and improving their photoelectric conversion efficiency and long-term stability. 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 multi-junction solar cells and improving their photoelectric conversion efficiency and long-term stability. 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.

[0305] Organic active materials are typically 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, while common electron acceptor materials include fullerene acceptors (such as PC). 61 BM, PC 71BM, 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.

[0306] 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.

[0307] 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.

[0308] 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 and long-term stability 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.

[0309] In other embodiments, the bandgap of the second light-absorbing layer is Eg3, where 1.65 eV ≤ Eg3 ≤ 2.2 eV; 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 and long-term stability 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.

[0310] 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 and long-term stability. Exemplarily, the third perovskite material includes APbI. z Br 3-z The material shown is defined as above, where 0 < z < 3.

[0311] 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 and long-term stability of the multi-junction solar cell. Furthermore, the second light-absorbing layer, acting as the top absorber of the cell, absorbs ultraviolet-visible light, protecting the perovskite layer as the bottom absorber.

[0312] In some embodiments, a multi-junction solar cell includes a first electrode, a first transport layer, 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 and long-term stability of the multi-junction solar cell.

[0313] In some embodiments, a multijunction solar cell includes a first electrode, a first transport layer, 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.

[0314] 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.

[0315] 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. The first charge carrier is a hole, the second charge carrier is an electron, and one of the third and fourth charge carriers is an electron and the other is a hole.

[0316] In some embodiments, a multi-junction solar cell includes a first electrode, 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. Where the first to fourth carriers are present, the first and third transport layers are identical and are hole transport layers, while the second and fourth transport layers are identical and are electron transport layers. Thus, the first electrode, the first transport layer, the perovskite layer, and optionally the second transport layer form a first cell unit, and the optional third transport layer, the optional second light-absorbing layer, the optional fourth transport layer, and the second electrode form a second cell unit. The 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 cell unit containing the perovskite layer and the second cell unit containing the second light-absorbing layer, ensuring connectivity between the two cell units. The tunneling layer, located between two cell units, primarily functions to facilitate the efficient transport of electrons and holes. Through the tunneling effect, electrons and holes can be transported from the bottom cell to the top cell, thereby reducing energy loss due to electron thermal relaxation and improving the cell's photoelectric conversion efficiency and long-term stability. Exemplarily, the second light-absorbing layer comprises a second perovskite material, resulting in a perovskite-perovskite multijunction solar cell. In another example, the second light-absorbing layer comprises crystalline silicon, resulting in a perovskite-crystalline silicon multijunction solar cell.

[0317] In some embodiments of this application, multi-junction solar cells 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 above; the materials of the electron transport layer or hole transport layer corresponding to the first and second cell units can be the same or different.

[0318] In some embodiments, 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.

[0319] In this application, the carrier recombination layer comprises one or more of the following: metallic materials, transparent conductive oxides, and carbon materials. Further, the transparent conductive oxide layer comprises, but is not limited to, one or more of the following: fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), tungsten-doped indium oxide (IWO), indium gallium zinc oxide (IGZO), and antimony-doped tin oxide (ATO). Further, the metallic materials include, but are not limited to, one or more of the following: gold, copper, silver, platinum, aluminum, and iron. Further, the carbon materials include, but are not limited to, one or more of the following: graphite, graphene, and carbon nanotubes.

[0320] In some implementations, 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 any two of the above values ​​as endpoints.

[0321] In some implementations, the components of the tunneling layer include, but are not limited to, PEDOT (poly-3,4-ethylenedioxythiophene), transparent metal oxides, etc.

[0322] 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.

[0323] 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.

[0324] 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 above. Thus, the first electrode, optionally the fifth transport layer, the perovskite layer, optionally the sixth transport layer, and the third electrode form the first cell unit; the fourth electrode, optionally the seventh transport layer, the second light-absorbing layer, optionally the eighth transport layer, and the second electrode form the second cell unit. The first and second cell units are electrically isolated by an insulating layer. Each cell unit has two electrodes, for a total of four electrodes. The circuits of the two cell units 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. Exemplarily, 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.

[0325] 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.

[0326] 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.

[0327] 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.

[0328] Non-limiting, the first electrode and the second electrode may each independently comprise a conductive material. The conductive material in the first electrode and the conductive material in the second electrode may each independently comprise an organic conductive material, an inorganic conductive material, or an organic-inorganic mixed conductive material.

[0329] As an example, organic-inorganic hybrid conductive materials include both organic and inorganic conductive components.

[0330] 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.

[0331] 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).

[0332] 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.

[0333] 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.

[0334] In some embodiments of this application, one of the first electrode and 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.

[0335] In some embodiments of this application, the electrode material of the first electrode includes at least one 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), indium tungsten oxide (IWO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, Mg, Mo, W and their alloys, graphite, graphene, and carbon nanotubes; optionally, it includes at least one of Ag, Cu, C, Au, Al, ITO, AZO, BZO or IZO, and further optionally, it includes at least one of Cu, Ag, and Au.

[0336] 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.

[0337] 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; non-limiting examples of TCO materials include ITO, FTO, etc.

[0338] 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.

[0339] 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 with appropriate energy levels, which can play one or more of the following roles: reducing energy level barriers, promoting energy level matching, improving carrier extraction efficiency, passivating interface defect states, protecting the light-absorbing layer, suppressing the oxidation and decomposition of the cell by water molecules and oxygen, improving photoelectric conversion efficiency and long-term stability, 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 the hole transport layer and the first electrode, interface modification layer between the electron transport layer and the second electrode, interface modification layer between the hole transport layer and the light-absorbing layer, and interface modification layer between the electron transport layer and the 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 may be provided between the electron transport layer and the second electrode. This insertion layer is used to block the transport of holes and may also be called a hole blocking layer. Examples of materials for the insertion layer include bath copper phosphate (BCP) and tin oxide.

[0340] In some embodiments of this application, the solar cell includes the following stacked structure: a transparent conductive glass substrate layer, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer (optionally), and a back electrode (the back electrode can be a metal electrode or a transparent conductive electrode).

[0341] 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.

[0342] In some embodiments of this application, the solar cell 100 includes Figure 3 The 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. 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.

[0343] In some embodiments of this application, the solar cell includes Figure 4The structure shown (a vertical cross-sectional view of the device) 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, 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 second transport layer 150, the perovskite layer 140, and the first 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 at least penetrate and divide the second electrode 160. Optionally, the third channel region P3 is used to penetrate and divide the second electrode 160, the second transport layer 150, the perovskite layer 140, and the first transport layer 130, and 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.

[0344] In some embodiments of this application, Figure 3-4 The substrate 110 in the structure shown is the light-incident side substrate.

[0345] 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.

[0346] 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.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] 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 a 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 an 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.

[0351] In some embodiments of the third aspect of this application, a method for preparing a solar cell is provided, comprising the following steps:

[0352] A first solution containing a first metal chloride is coated to form a first wet film. After a first drying and a first annealing, a perovskite precursor solution containing non-chloride monovalent anions is coated to form a perovskite precursor wet film. A second drying and a second annealing are then performed to form a perovskite layer.

[0353] Non-chlorinated monovalent anions are selected from the group consisting of non-chlorinated halide anions and pseudohalogen anions.

[0354] The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anions in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%;

[0355] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there is a second region with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0356] The first relative concentration of chlorine in the first region is greater than that in the second region.

[0357] Since light arrives first on the incident side, the lattice of the first surface of the perovskite layer (i.e., the side closest to the incident light) is suddenly interrupted, generating a large number of uncoordinated dangling bonds and vacancies. This further exacerbates surface defects, resulting in significantly greater interface defects in the first region (the near-surface region close to the incident light) compared to the second region (the central region of the perovskite bulk phase). Coating a first solution containing a first metal chloride into a first wet film can introduce chlorine into the perovskite layer and regulate its distribution, promoting effective enrichment of chlorine on the first surface. Simultaneously, a small amount of chlorine can migrate into the perovskite bulk phase, making the first relative concentration of chlorine in the first region greater than that in the second region.

[0358] Furthermore, non-chlorine monovalent anions, as one of the main components of the perovskite layer, have a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the defined first relative concentration of chlorine can characterize the content distribution of chlorine in the perovskite layer. This application introduces chlorine into the perovskite layer. On the one hand, chlorine near the perovskite layer interface (such as in the first region) can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing perovskite bulk defects and passivating perovskite grain boundaries. On the other hand, chlorine in the bulk phase (such as in the second region) can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, by controlling the chlorine content in the perovskite layer within the above-mentioned range, it is beneficial to reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell. Simultaneously, by controlling the first relative concentration of chlorine in the first region to be greater than the first relative concentration of chlorine in the second region... Regarding concentration, the chlorine concentration near the perovskite layer interface can be controlled to be higher than that in the middle of the perovskite bulk phase. This ensures that the chlorine concentration in the corresponding region matches the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as near the surface and in the middle of the bulk phase), improving the overall uniformity of the perovskite layer structure. Simultaneously, it can also consider the overall amount of chlorine used, meaning that a smaller amount is needed to achieve the goals of defect passivation and improving the uniformity of the perovskite layer structure and crystal quality. Furthermore, the distribution of non-chlorine anions differs between the second and first surfaces, exhibiting a decreasing distribution gradient from the second surface to the first surface. By controlling the chlorine content in the first region to be higher than that in the second region, the non-chlorine anion gradient can be weakened, resulting in a more uniform distribution and improved perovskite uniformity. Therefore, this application can effectively reduce perovskite defects while maintaining the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0359] In some embodiments of the fourth aspect of this application, a method for preparing a solar cell is provided, comprising the following steps:

[0360] A first solution containing a first metal chloride is coated to form a first wet film. After a first drying and a first annealing, a perovskite precursor solution containing non-chloride monovalent anions is coated to form a perovskite precursor wet film. A second drying and a second annealing are then performed to form a perovskite layer.

[0361] Non-chlorinated monovalent anions are selected from the group consisting of non-chlorinated halide anions and pseudohalogen anions.

[0362] The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anions in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%;

[0363] The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there is a second region with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively.

[0364] The first percentage of chlorine is defined as the ratio of the amount of chlorine in a preset region to the total amount of chlorine in the perovskite layer. The first percentage of chlorine in the first region is greater than that in the second region.

[0365] Coating a first solution containing a first metal chloride into a first wet film can introduce chlorine into the perovskite layer and regulate the distribution of chlorine, promoting the effective enrichment of chlorine on the first surface. At the same time, a small amount of chlorine can migrate into the perovskite phase, making the first molar proportion of chlorine in the first region greater than that in the second region.

[0366] As one of the main components of the perovskite layer, the non-chlorine monovalent anion has a relatively stable content and can be used as a benchmark to evaluate the content of other components. Therefore, the first relative concentration of chlorine can characterize the content distribution of chlorine in the perovskite layer. By introducing chlorine into the perovskite layer, on the one hand, near-surface chlorine can fill uncoordinated dangling bonds and vacancies, forming a quasi-two-dimensional thin film with the perovskite material, reducing bulk defects and passivating perovskite grain boundaries. On the other hand, bulk chlorine can reduce shallow-level defects through coordination and fix the lattice, thereby effectively passivating perovskite defects and improving the crystal quality of the perovskite layer. Furthermore, controlling the chlorine content in the perovskite layer within the aforementioned range is beneficial for reducing perovskite defects while taking into account the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell. At the same time, by controlling the chlorine content in the first region to be greater than that in the second region, the chlorine content in the corresponding region is matched with the number of defects in that region, which is beneficial for fully passivating defects in various regions of the perovskite layer (such as near-surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, while taking into account the overall amount of chlorine used, that is, achieving the purpose of passivating defects and improving the uniformity of the perovskite layer structure and crystal quality with a smaller amount. Therefore, this application can effectively reduce perovskite defects while taking into account the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of solar cells.

[0367] In some embodiments, the perovskite precursor solution containing a non-chlorine monovalent anion further includes a second metal chloride.

[0368] The perovskite precursor solution containing non-chlorine monovalent anions facilitates the introduction of chlorine into the perovskite bulk phase. Simultaneously, due to the large radius of chlorine, during the annealing and ripening process of the perovskite material, as the solvent evaporates upwards from the system, chlorine is squeezed out of the bulk lattice and enriched on the second surface. This results in a higher chlorine content in the third region compared to the second region, which is beneficial for the formation of a quasi-two-dimensional thin film between chlorine and the perovskite material. This reduces perovskite bulk defects, passivates perovskite grain boundaries, increases open-circuit voltage, and further improves the photoelectric conversion efficiency and long-term stability of the solar cell.

[0369] Therefore, by coating the surface of the first transport layer with a first solution containing a first metal chloride, and then preparing the perovskite layer using a perovskite precursor solution containing non-chlorine monovalent anions, the distribution of chlorine in the first, second, and third regions of the perovskite layer can be effectively regulated. This allows chlorine to be effectively enriched in the first and third regions of the perovskite layer, while its content is lower in the second region. This effectively reduces perovskite defects and balances the crystal quality and resistance of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0370] In some embodiments, the second metal chloride comprises PbCl2. PbCl2 has low solubility and readily accumulates on the surface of the perovskite layer to form the defined perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0371] In some embodiments, the molar percentage of chlorine in the second metal chloride relative to the non-chlorine monovalent anion is 0.05% to 9%, for example, 0.05%, 0.10%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 7%, 8%, 9%, etc. Controlling the molar percentage of chlorine relative to non-chlorine monovalent anions in the second metal chloride within the aforementioned range is beneficial for ensuring that the chlorine content in the third region is greater than that in the second region. This facilitates the formation of a quasi-two-dimensional thin film between chlorine and the perovskite material, reducing perovskite bulk defects, passivating perovskite grain boundaries, and increasing open-circuit voltage. Simultaneously, by coating the surface of the first transport layer with a first solution containing the first metal chloride, the distribution of chlorine in the first, second, and third regions of the perovskite layer can be effectively regulated. This results in effective enrichment of chlorine in the first and third regions of the perovskite layer, while maintaining a lower content in the second region. This effectively reduces perovskite defects and balances the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0372] In some embodiments, the concentration of the second metal chloride in the perovskite precursor solution containing non-chlorine monovalent anions is 0.1 mg / mL to 30 mg / mL, for example, 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, etc. This facilitates a higher chloride content in the third region than in the second region. Combined with the coating of the first transport layer surface with a first solution containing the first metal chloride, the chloride distribution in the first, second, and third regions of the perovskite layer can be effectively regulated. This results in effective chloride enrichment in the first and third regions of the perovskite layer, while maintaining a lower chloride content in the second region. This effectively reduces perovskite defects while maintaining the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0373] In some embodiments, the second metal chloride is first mixed and ground with lead halide to prepare a mixed halide; the mixed halide is then mixed with other components to prepare a perovskite precursor solution containing non-chlorine monovalent anions.

[0374] Understandably, mixing and grinding the second metal chloride with lead halide first can achieve molecular-level dispersion of the second metal chloride in lead halide, thereby promoting the role of chlorine in the second metal chloride.

[0375] In some embodiments, the D50 of the mixed halides is <0.1 μm. This facilitates molecular-level dispersion of the second metal chloride in lead halide and promotes dispersion of the mixed halides in perovskite precursor solutions containing non-chlorine monovalent anions.

[0376] In some embodiments, the mass concentration of the second metal chloride in the mixed halide is 0.05wt% to 5.5wt%, for example, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 5.5wt%, etc. This allows for the control of the concentration of the second metal chloride in the perovskite precursor solution containing non-chlorine monovalent anions, which is beneficial for ensuring that the chlorine content in the third region is greater than that in the second region. Simultaneously, by coating the surface of the first transport layer with a first solution containing the first metal chloride, the distribution of chlorine in the first, second, and third regions of the perovskite layer can be effectively adjusted. This results in effective enrichment of chlorine in the first and third regions of the perovskite layer, while maintaining a lower content in the second region. This effectively reduces perovskite defects while maintaining the crystal quality and resistivity of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0377] In some embodiments, the perovskite precursor solution further includes a second solvent, the second solvent comprising at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0378] In some embodiments, the first metal chloride includes PbCl2. PbCl2 has low solubility and readily precipitates competitively on the first surface of the perovskite layer, accumulating on the surface of the perovskite layer to form the defined perovskite layer, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0379] In some embodiments, the molar percentage of chlorine in the first metal chloride relative to the non-chlorinated monovalent anion is 0.001% to 0.05%, optionally 0.001% to 0.02%, such as 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc. Controlling the molar percentage of chlorine in the first metal chloride relative to the non-chlorinated monovalent anion within the above range can adjust the distribution of chlorine, promote the effective enrichment of chlorine on the first surface, and allow a small amount of chlorine to migrate into the perovskite bulk phase, making the chlorine content in the first region greater than that in the second region. This is beneficial for fully passivating defects in various regions of the perovskite layer (such as near the surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, and simultaneously maintaining the conductivity of the first region, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0380] Understandably, after the first and second metal chlorides are added to the perovskite layer, they undergo some natural migration and disperse in other functional layers such as the first transport layer. Therefore, the total amount of the first and second metal chlorides differs somewhat from the chlorine content in the final perovskite layer.

[0381] In some embodiments, the concentration of the first metal chloride in the first solution is 1 mg / mL to 20 mg / mL, for example, 1 mg / mL, 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, etc. This facilitates the formation of a first wet film, promotes the effective enrichment of chlorine on the first surface and its small distribution in the perovskite bulk phase, and makes the chlorine content in the first region greater than that in the second region. This is beneficial for fully passivating defects in various regions of the perovskite layer (such as near the surface and the middle of the bulk phase), improving the uniformity of the overall structure of the perovskite layer, while also maintaining the conductivity of the first region, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0382] In some embodiments, the thickness of the first wet film is 1 μm to 20 μm, optionally 3 μm to 18 μm. This allows for control over the content of the first metal chloride, promoting effective enrichment of chlorine on the first surface and a small distribution in the perovskite bulk phase. This results in a higher chlorine content in the first region than in the second region, which is beneficial for effectively passivating defects in various regions of the perovskite layer (such as near the surface and the middle of the bulk phase), improving the uniformity of the overall perovskite layer structure, and simultaneously maintaining the conductivity of the first region, thereby improving the photoelectric conversion efficiency and long-term stability of the solar cell.

[0383] In some embodiments, the first solution further includes a first solvent; the first solvent includes at least one of N,N-dimethylacetamide and water. The solvent facilitates the dissolution of the first metal chloride, improves the homogeneity of the first solution, and promotes the effective enrichment of chlorine on the first surface and its small-scale distribution in the perovskite phase, resulting in a higher chlorine content in the first region than in the second region.

[0384] In some embodiments, the first drying includes vacuum drying at a pressure of 10 Pa to 500 Pa, such as 10 Pa, 50 Pa, 100 Pa, 200 Pa, 300 Pa, 400 Pa, 500 Pa, etc.; a drying temperature of 20°C to 30°C, such as 20°C, 25°C, 30°C, etc.; and a drying time of 50 s to 100 s, such as 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, etc. These first drying conditions are beneficial for improving the uniformity of drying and promoting the effective enrichment of chlorine on the first surface and its small-scale distribution in the perovskite phase.

[0385] In some embodiments, the second drying includes vacuum drying, with a pressure of 10 Pa to 50 Pa, such as 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa, etc.; a drying temperature of 25°C to 50°C, such as 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, etc.; and a drying time of 50 s to 80 s, such as 50 s, 60 s, 70 s, 80 s, etc. The above-mentioned first drying conditions are beneficial to improving the uniformity of drying and obtaining a perovskite layer with better uniformity.

[0386] In some embodiments, the conditions for the first annealing include: a temperature of 40°C to 60°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, etc.; and a time of 3 min to 10 min, such as 3 min, 5 min, 7 min, 9 min, 10 min, etc.

[0387] In some embodiments, the second annealing includes: performing gradient annealing at temperatures T1 and T2, where temperature T1 > temperature T2.

[0388] Annealing at temperature T1 promotes chlorine migration and perovskite nucleation; then annealing at temperature T2 promotes perovskite grain growth and reduces the adverse effects of high temperature on the perovskite matrix, thereby improving the perovskite crystal quality and enhancing the photoelectric conversion efficiency and long-term stability of solar cells.

[0389] In some embodiments, temperature T1 is 150℃~170℃, such as 150℃, 155℃, 160℃, 165℃, 170℃, etc.; temperature T2 is 100℃~120℃, such as 100℃, 105℃, 110℃, 115℃, 120℃, etc. This is beneficial for improving the crystallization quality of perovskite.

[0390] In some embodiments, the annealing time at temperature T1 is 2 min to 5 min, for example, 2 min, 3 min, 4 min, 5 min, etc.; and the annealing temperature at temperature T2 is 5 min to 15 min, for example, 5 min, 7 min, 9 min, 11 min, 13 min, 15 min, etc. This is beneficial for improving the crystallization quality of perovskite.

[0391] Specifically, the solar cell is an inverted solar cell, and its fabrication method includes the following steps:

[0392] Step 1: Prepare the base layer;

[0393] Step 2: Prepare a conductive layer on the substrate to form the first electrode;

[0394] Step 3: Fabricate a hole transport layer on a transparent conductive glass electrode;

[0395] Step 4: Prepare a perovskite layer on the hole transport layer;

[0396] Step 5: Prepare an electron transport layer on the perovskite layer;

[0397] Step 6: Fabricate electrodes on the electron transport layer.

[0398] Specifically, between steps 3 and 4, or between steps 4 and 5, a step of preparing an interface modification layer may also be included.

[0399] 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.

[0400] In some embodiments of the fifth aspect of this application, a photovoltaic module 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. The aforementioned photovoltaic module has improved photoelectric conversion efficiency and long-term stability.

[0401] In some embodiments of the sixth 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.

[0402] The aforementioned electrical devices have improved photoelectric conversion efficiency and long-term stability.

[0403] In some embodiments of the seventh 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.

[0404] The aforementioned power generation device has improved photoelectric conversion efficiency and long-term stability.

[0405] 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.

[0406] 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.

[0407] 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.

[0408] Another example of an electrical device could be a mobile phone, tablet, laptop, calculator, etc.

[0409] Another example of an electrical device could be a wearable device, such as a watch.

[0410] 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.

[0411] In the following embodiments, "room temperature" refers to 20°C-30°C, and further, it can be 25°C.

[0412] In the following examples, unless otherwise specified, FTO is fluorine-doped tin oxide, FAI is formamidinium iodide, DMF is N,N-dimethylformamide, and DMSO is dimethyl sulfoxide.

[0413] Example 1

[0414] The solar cell uses an inverted pin structure and is fabricated as follows:

[0415] 1) Fabrication of the first electrode:

[0416] A set of FTO conductive glass with a specification of 300mm×300mm was used to etch the first channel region with an ultraviolet laser. The width of the first channel region was about 20μm. The entire glass was divided into 42 sub-cells along the long side. Each sub-cell was 6mm wide and the series resistance of different sub-cells was greater than 10MΩ. The top and bottom 12mm were used as the component welding area.

[0417] The etched conductive glass surface was cleaned twice with acetone and isopropanol, then immersed in deionized water for ultrasonic treatment for 10 minutes, dried in a forced-air drying oven, and placed in a drying room (humidity below 2% RH, relative humidity) to obtain the first electrode with a glass substrate layer (denoted as FTO conductive glass). The thickness of the first electrode is approximately 590 nm.

[0418] 2) Hole transport layer preparation: The cleaned FTO conductive glass is placed in a magnetron sputtering device to deposit a layer of nickel oxide to form a hole transport layer (thickness of about 20 nm).

[0419] 3) Preparation of electron blocking layer: A wet film (4 μm thick) of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) solution (0.30 mg / mL, isopropanol solution) was coated on the hole transport layer using a slit coater. The film was then dried with a 0.4 MPa air knife and annealed at 50 °C for 5 min to form an electron blocking layer (approximately 1 nm thick).

[0420] 4) Preparation of the perovskite layer:

[0421] a) Preparation of PbCl2 thin film: a1) PbCl2 (first metal chloride) was carefully ground in an agate mortar until the powder became a smooth, fine powder. Grinding was stopped (approximately 10 min, particle size <0.1 μm); b1) 0.6 g of PbCl2 was dissolved in 100 mL of a mixed solvent of H2O:DMAc (N,N-dimethylacetamide) with a volume ratio of 9:1 (first solvent). The solution was stirred at 300 rpm and 45 °C for 10 h to prepare the PbCl2 thin film precursor solution; c1) The PbCl2 thin film precursor solution was sonicated for 30 min, filtered through a 0.22 μm filter membrane, and then a PbCl2 thin film (first wet film, the thickness of which is approximately 6 μm) was coated on the passivation layer surface using a slot coater. Vacuum was applied (first drying, pressure 10 Pa, temperature 25 °C). After annealing at 100℃ for 10 min (first annealing) for 60 s, a PbCl2 thin film (thickness approximately 6 nm) is formed.

[0422] b) Add PbCl2 and PbI2 to a ball mill at a mass ratio of 2.15:100 and ball mill at 500 rpm for 24 hours; transfer the ball-milled powder to an agate mortar and grind it carefully for about 30 minutes to achieve a particle size D.50 <0.1μm, material X1 was obtained;

[0423] c) Add PbCl2 and PbBr2 to a ball mill at a mass ratio of 2.15:100 and ball mill at 500 rpm for 24 hours; transfer the ball-milled powder to an agate mortar and grind it carefully for about 30 minutes to achieve a particle size D. 50 <0.1μm, material X2 was obtained;

[0424] d) Prepare a solution containing 1M FA 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 Perovskite precursor solution of precursor materials 3: Weigh 0.881 g of material X2 and 35.774 g of material X1, 1.039 g of CsI, and 13.070 g of FAI, then add 80 mL of a mixed solvent of DMF and DMSO (volume ratio 9:1) (second solvent). Stir at 200 rpm for 6 h, then filter through a 0.22 μm PTFE membrane to obtain the perovskite precursor solution. In this example, the concentration of PbCl2 in the perovskite precursor solution is approximately 9.64 mg / mL.

[0425] e) The above perovskite precursor solution was slit-coated onto a PbCl2 film to form a wet perovskite precursor film. After vacuuming (second drying, pressure 10 Pa, temperature 25 °C, time 70 s), it was annealed in an oven at 160 °C (temperature T1) for 3 min, and then quickly transferred to 110 °C (temperature T2) for annealing for 10 min to obtain a perovskite layer (the total thickness of the perovskite layer is about 440 nm).

[0426] 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, depositing a C60 layer with a thickness of approximately 25 nm, and then transferring it to an atomic layer deposition (ALD) device to deposit a SnO2 layer with a thickness of approximately 25 nm at 100 °C as an electron transport layer.

[0427] 6) Preparation of hole blocking layer: After depositing the electron transport layer, a copper (Cu) layer with a thickness of about 10 nm is deposited on the surface of the electron transport layer and then removed by vacuum breaking; then, P2 is laser etched, with a width of 150 μm and a depth to the surface of the FTO layer, and the interval between P2 and P1 is 40 μm.

[0428] 7) Preparation of the second electrode: Then, the substrate is placed back into the vapor deposition equipment and evacuated to a vacuum level of 4 × 10⁻⁶. -4 After Pa, another ITO layer is deposited, with a thickness of about 100 nm. After cooling, the vacuum is broken and the P3 layer is laser-etched. The width of P3 is 15 μm and the depth is etched to the surface of the FTO layer. The interval between P3 and P2 is 20 μm (the positions of the etching lines are P1 / P2 / P3 in sequence). Then, infrared edge cleaning is used on the module, that is, 12 mm is etched on each side of the module. In this way, the solar cell is obtained.

[0429] Examples 2-8

[0430] 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.

[0431] In Example 8, the hole transport layer was prepared using a self-assembled monomolecular material. Steps 2a)-2b) were adjusted as follows: The cleaned FTO was placed in a slot coater, and a solution of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) (0.60 mg / mL, isopropanol solution) was coated on the FTO to form a wet film (12 μm thick). Then, it was dried with a 0.2 MPa air knife and annealed at 50°C for 5 min to form a hole transport layer (approximately 20 nm thick). The remaining steps were the same as in Example 1.

[0432] Example 9

[0433] Except for replacing material X1 with PbI2 and material X2 with PbBr2 during the preparation of the perovskite precursor solution, i.e., not adding PbCl2 to the perovskite precursor solution, the other operation steps are the same as in Example 6.

[0434] Comparative Example 1

[0435] Except for the different concentrations of X1 and X2 in steps 3b) and 3c) and the different thickness of the PbCl2 film in step 3a), the other operation steps are the same as in Example 1, as detailed in Table 1.

[0436] Test case

[0437] 1. Relative concentration or molar percentage of each element or ion in the perovskite device:

[0438] The perovskite component was etched to a depth of 10 nm to 100 nm in the FTO bulk phase. Time-of-flight secondary ion mass spectrometry (TOF-SIMs, PHI nanoTOF Ⅲ Time-of-Flight SIMS) was used in dual modes of cross-sectional imaging and depth profiling, combined with scanning 3D imaging, to determine the concentration using characteristic secondary ions as a fingerprint. The number of atoms or the integral count intensity of each atom or element in the test area were counted, and the molar percentage of the target element or ion relative to a specific element (X1 element or nickel element) was calculated to obtain the first relative concentration or the second relative concentration of chlorine. Specifically, the perovskite layer thickness was 440 nm, the etching rate was 2 nm / s, and the etching time ranged from 200 s to 420 s; the nickel oxide layer thickness was 20 nm, the etching time was 80 s, and the etching rate was 0.25 nm / s, and the etching time ranged from 420 s to 500 s. Based on the time, the corresponding positions could be determined, thereby obtaining the number of ions of each element in different preset regions and calculating the relative concentration or the percentage of substance.

[0439] Qualitative analysis of Example 1 as follows: Figure 5 As shown in the figure, the relationship between the first relative concentration of chlorine and the test time in the perovskite layer of Example 1 is as follows. Figure 6 The relationship between the first mole fraction of chlorine in the perovskite layer and the test time in Example 1 of this application is shown in the figure below. Figure 7 The relationship between the second mole fraction of chlorine in the hole transport layer and the test time in Example 1 of this application is shown in the figure below. Figure 8 The relationship between the second relative concentration of chlorine in the hole transport layer and the test time in Example 1 of this application is shown in the figure below. Figure 9 .

[0440] The relationship between the percentage of nickel in the third substance and the test time in Examples 2-7 and 9 is consistent with the trend in Example 1, and will not be repeated here.

[0441] In Example 1, the second relative concentration of chlorine in the first transport layer is 24.43%. The second relative concentration of chlorine in the region extending 2.5 nm from the surface of the hole transport layer away from the perovskite layer (i.e., the third surface) along the thickness direction of the hole transport layer toward the interior of the hole transport layer (referred to as the sixth region) is 38.90%. The second relative concentration of chlorine in the region extending 2.5 nm from the first surface along the thickness direction of the hole transport layer toward the interior of the first transport layer (referred to as the seventh region) is 13.82%. In Examples 2-7 and 9, the second relative concentration of chlorine in the first transport layer is between 15% and 40%, and the distribution trend is similar to that of Example 1. The second relative concentration of chlorine in the sixth region is greater than that in the seventh region.

[0442] The average molar volume concentration of chlorine in the perovskite layer of Example 1 was 0.000002912 mmol / cm³. 3 In other embodiments, the average molar volume concentration of chlorine in the perovskite layer is 0.000001 mmol / cm³. 3 ~0.00001mmol / cm 3 between.

[0443] 2. Photoelectric conversion efficiency:

[0444] Initial device performance (solar cells used in solar cells)

[0445] Under normal temperature and pressure (25℃, 1 atmosphere), a standard light source with AM1.5G sunlight simulation was used for testing, conforming to the national standard IEC61215. Crystalline silicon solar cells were used to correct the light intensity to achieve the intensity of one solar cell. A four-channel digital source meter (Keithley 2440) was used to measure the current-voltage characteristic curve (i.e., current-voltage curve) of the solar cell under the illumination of the light source, and the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), photoelectric conversion efficiency, and long-term stability (PCE) of the solar cell were obtained.

[0446] The photoelectric conversion efficiency and long-term stability (PCE) are calculated as follows:

[0447] PCE = Pout / Pin

[0448] = Voc×Jsc×[(Vmpp×Jmpp) / (Voc×Jsc)] / Pin

[0449] = Voc×Jsc×FF / Pin

[0450] 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 .

[0451] 3. Device stability measurement

[0452] Testing was conducted according to the IEC 61215 standard. After the initial performance test, the cell under test was subjected to PID-96h, 1Sun 85℃-96h, and TC-30cycles treatments, followed by another photoelectric conversion efficiency test (each test continued until forward and reverse scans showed no hysteresis, and the photoelectric conversion efficiency and long-term stability were recorded). The ratio of the photoelectric conversion efficiency and long-term stability of the cell after the above treatments to the initial efficiency was calculated as the normalized efficiency of the solar cell after the above treatments, which can be denoted as "PID-96h retention rate", "1Sun 85℃-96h retention rate", and "TC-30cycles retention rate". That is, retention rate = (photoelectric conversion efficiency after treatment / initial photoelectric conversion efficiency and long-term stability) × 100%, which is used to evaluate stability. The higher the initial normalized efficiency, the better the device stability.

[0453] The composition and performance of the solar cells in the examples and comparative examples are shown in Tables 1-3.

[0454] Table 1

[0455]

[0456] Note: In Table 1, the first region refers to the region extending 10 nm to 20 nm from the first surface into the perovskite layer; the region extending 10 nm from H / 2 of the perovskite layer into the second surface (i.e., the region extending 1 / 2 × H to 1 / 2 × H + 10 nm from the first surface into the perovskite layer); and the third region refers to the region extending 10 nm to 20 nm from the second surface into the perovskite layer.

[0457] Table 2

[0458]

[0459] Note: The specific locations of the first to third regions are as shown in Table 1.

[0460] Table 3. Composition and performance of solar cells in the examples and comparative examples.

[0461]

[0462] Note: M1 refers to the percentage of chlorine in the region (i.e., the sixth region) extending 2.5 nm from the surface of the hole transport layer away from the perovskite layer (i.e., the third surface) along the thickness direction of the hole transport layer toward the interior of the hole transport layer, based on the total amount of chlorine in the first transport layer; M2 refers to the percentage of chlorine in the region (i.e., the seventh region) extending 2.5 nm from the first surface along the thickness direction of the hole transport layer toward the interior of the first transport layer, based on the total amount of chlorine in the first transport layer.

[0463] As can be seen from Tables 1-3, the first relative concentration of chlorine in the perovskite layer of the solar cells prepared in Examples 1-9 of this application is between 0 and 0.6% (excluding 0), and the first relative concentration of chlorine in the first region is greater than that in the second region, or the first molar percentage of chlorine in the first region is greater than that in the second region. Consequently, the solar cells have good photoelectric conversion efficiency and long-term stability. The photoelectric conversion efficiency and long-term stability of the solar cells prepared in Examples 1-9 are significantly better than those of Comparative Example 1.

[0464] Furthermore, as can be seen from Examples 1, 6, and 9, the combined use of a first metal chloride and a second metal chloride allows for adjustment of the relative concentrations in the first, second, and third regions, which is beneficial for further improving photoelectric conversion efficiency and long-term stability. A comparison of Examples 1-9 and Comparative Example 1 shows that an excessively high first relative concentration of chlorine in the perovskite layer leads to a deterioration in photoelectric conversion efficiency and long-term stability. This is attributed to the fact that excessively high chlorine content increases the resistance of the perovskite layer, induces lattice distortion, and damages the integrity of the perovskite crystal.

[0465] It is understood that the perovskite layer described above is not limited to the preparation method 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 cell protected by the first aspect of this application. For example, the first metal chloride and the second metal chloride may not be added, and the PbCl2 thin film may not be set. Instead, the solar cell protected by the first aspect of this application may be obtained by adjusting other process parameters (e.g., processing in a chlorine-containing atmosphere, or by adding chlorine elements in segments in different structural layers). This application does not limit the preparation method of the solar cell protected by the first aspect.

[0466] 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, Includes a perovskite layer, wherein the perovskite layer includes non-chlorine monovalent anions, wherein the non-chlorine monovalent anions are selected from the group consisting of non-chlorine halide anions and pseudohalogen anions. The perovskite layer also includes chlorine; the molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, 0 < M0 ≤ 6%; The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively. The first relative concentration of chlorine in the first region is greater than the first relative concentration of chlorine in the second region.

2. The solar cell as described in claim 1, characterized in that, The first relative concentration of chlorine in the perovskite layer is 0.004% to 5.17%, and can be selected as 0.08% to 4%.

3. The solar cell as described in claim 1, characterized in that, It meets one or more of the following characteristics: (1) The first relative concentration of chlorine in the first region is 0.003%~1.5%, and can be selected as 0.05%~1.5%; (2) The first relative concentration of chlorine in the second region is 0.00001% ~ 0.05%, which can be selected as 0.0005% ~ 0.05%.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The ratio of the first relative concentration of chlorine in the first region to the first relative concentration of chlorine in the second region is (29~105):1, and can be selected as (32~88):

1.

5. The solar cell according to any one of claims 1 to 4, characterized in that, A third region with a thickness of 5 nm to 10 nm exists within a region extending 20 nm from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer. The first relative concentration of chlorine in the third region is greater than the first relative concentration of chlorine in the second region.

6. The solar cell as described in claim 5, characterized in that, The first relative concentration of chlorine in the third region is less than the first relative concentration of chlorine in the first region; Optionally, the first relative concentration of chlorine in the third region is 0.0005% to 0.6%, and optionally 0.01% to 0.5%.

7. The solar cell according to any one of claims 1 to 6, characterized in that, The region extending d1 from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is denoted as the fourth region, where 1 / 2×H-10nm≤d1≤1 / 2×H+10nm; the direction from the first surface to the second surface in the thickness direction of the perovskite layer is denoted as the Z1 direction, and the first relative concentration of chlorine in the fourth region generally shows a decreasing trend in the Z1 direction.

8. The solar cell according to any one of claims 1 to 7, characterized in that, The region extending d2 from the second surface toward the interior of the perovskite layer along the thickness direction of the perovskite layer is designated as the fifth region, where 1 / 2×H-10nm≤d2≤1 / 2×H+10nm; the direction from the first surface to the second surface in the thickness direction of the perovskite layer is designated as the Z1 direction, and the first relative concentration of chlorine in the fifth region generally shows an increasing trend in the Z1 direction.

9. A solar cell, characterized in that, Includes a perovskite layer, wherein the perovskite layer includes non-chlorine monovalent anions, wherein the non-chlorine monovalent anions are selected from the group consisting of non-chlorine halide anions and pseudohalogen anions. The perovskite layer also includes chlorine; the molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, 0 < M0 ≤ 6%; The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively. The percentage of chlorine in a predetermined region of the perovskite layer relative to the total amount of chlorine in the perovskite layer is denoted as the first percentage of chlorine in that predetermined region. The first percentage of chlorine in the first region is greater than the first percentage of chlorine in the second region.

10. The solar cell as claimed in claim 9, characterized in that, The first substance of chlorine in the first region has a first substance content of 6% to 15%, which can be selected as 9% to 15%.

11. The solar cell as claimed in claim 9 or 10, characterized in that, The first substance of chlorine in the second region accounts for 0.3% to 2%, and can be selected as 0.4% to 1%; Optionally, the ratio of the amount of chlorine in the first substance in the first region to the amount of chlorine in the second region is (10~35):

1.

12. The solar cell according to claims 9-11, characterized in that, A third region with a thickness of 5 nm to 10 nm exists within a region extending 20 nm from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer. The proportion of chlorine in the third region is greater than that in the second region.

13. The solar cell according to claim 12, characterized in that, The first substance of chlorine in the third region has a content of 5% to 14%, which can be selected as 5% to 10%.

14. The solar cell as claimed in claim 12 or 13, characterized in that, The proportion of chlorine in the third region is less than the proportion of chlorine in the first region.

15. The solar cell according to any one of claims 9 to 14, characterized in that, The region extending d1 from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is designated as the fourth region, where 1 / 2×H-10nm≤d1≤1 / 2×H+10nm; the direction from the first surface to the second surface in the thickness direction of the perovskite layer is designated as the Z1 direction, and the proportion of the first substance of chlorine in the fourth region generally decreases in the Z1 direction.

16. The solar cell according to any one of claims 9 to 15, characterized in that, The region extending d2 from the second surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer is designated as the fifth region, where 1 / 2×H-10nm≤d2≤1 / 2×H+10nm; the direction from the first surface to the second surface in the thickness direction of the perovskite layer is designated as the Z1 direction, and the proportion of the first substance of chlorine in the fifth region generally increases in the Z1 direction.

17. The solar cell according to any one of claims 1 to 16, characterized in that, The average molar volume concentration of chlorine in the perovskite layer is 0.000001 mmol / cm³. 3 ~0.00001mmol / cm 3 .

18. The solar cell according to any one of claims 1 to 17, characterized in that, The solar cell includes a first transport layer stacked with the perovskite layer; the first transport layer includes chlorine.

19. The solar cell as claimed in claim 18, characterized in that, The first transport layer comprises nickel oxide.

20. The solar cell as claimed in claim 19, characterized in that, The direction from the second surface to the first surface in the thickness direction of the perovskite layer is denoted as the Z2 direction. The proportion of the amount of chlorine in a preset region of the first transport layer relative to the total amount of chlorine in the first transport layer is denoted as the second proportion of chlorine in the preset region; the proportion of the second proportion of chlorine in the first transport layer generally shows an upward trend in the Z2 direction.

21. The solar cell as claimed in claim 19 or 20, characterized in that, The molar percentage of chlorine in a preset region of the first transport layer relative to the nickel in the same preset region is denoted as the second relative concentration of chlorine in the preset region. The second relative concentration of chlorine in the first transport layer is 15% to 40%.

22. The solar cell according to any one of claims 1 to 21, characterized in that, The non-chlorine monovalent anions in the perovskite layer include iodide ions; Optionally, based on the total amount of non-chlorinated monovalent anions in the perovskite layer, the proportion of iodide ions in the perovskite layer is 80.0% to 99.8%.

23. The solar cell according to any one of claims 1 to 22, characterized in that, The non-chlorine monovalent anions in the perovskite layer include bromide ions; Optionally, based on the total amount of non-chlorine monovalent anions in the perovskite layer, the proportion of bromide ions in the perovskite layer is 0.2% to 20%.

24. The solar cell according to any one of claims 1 to 23, characterized in that, The perovskite layer includes a first perovskite material, which includes the non-chlorine monovalent anion.

25. The solar cell according to any one of claims 1 to 24, characterized in that, The chlorine element in the perovskite layer exists in the form of chloride ions; Optionally, the solar cell further includes a first transport layer stacked with the perovskite layer, the first transport layer including chlorine element, the chlorine element in the first transport layer existing in the form of chloride ions.

26. The solar cell according to any one of claims 1 to 25, characterized in that, The solar cell is a multi-junction solar cell, which includes a first cell unit, and the first cell unit includes the perovskite layer. Optionally, the first battery cell further includes a first transport layer stacked with the perovskite layer.

27. The solar cell according to claim 26, 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.

28. The solar cell according to claim 26 or 27, 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.

29. The solar cell according to any one of claims 26 to 28, characterized in that, The multi-junction solar cell includes a first electrode, a first transport layer, 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 first transport layer away from the perovskite layer, and the second electrode is located on the side of the second light-absorbing layer away from the carrier recombination layer or tunneling layer.

30. The solar cell according to any one of claims 26 to 28, characterized in that, The multi-junction solar cell includes a first electrode, a first transport layer, 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 along its thickness direction. 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 first transport layer away from the perovskite layer, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode.

31. A method for preparing a solar cell, characterized in that, Includes the following steps: A first solution containing a first metal chloride is coated to form a first wet film. After a first drying and a first annealing, a perovskite precursor solution containing non-chloride monovalent anions is coated to form a perovskite precursor wet film. A second drying and a second annealing are then performed to form a perovskite layer. The non-chlorinated monovalent anion is selected from the group consisting of non-chlorinated halide anions and pseudohalogen anions. The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%; The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively. The first relative concentration of chlorine in the first region is greater than the first relative concentration of chlorine in the second region.

32. A method for preparing a solar cell, characterized in that, Includes the following steps: A first solution containing a first metal chloride is coated to form a first wet film. After a first drying and a first annealing, a perovskite precursor solution containing non-chloride monovalent anions is coated to form a perovskite precursor wet film. A second drying and a second annealing are then performed to form a perovskite layer. The non-chlorinated monovalent anion is selected from the group consisting of non-chlorinated halide anions and pseudohalogen anions. The molar percentage of chlorine in a predetermined region of the perovskite layer relative to the non-chlorine monovalent anion in that predetermined region is denoted as the first relative concentration of chlorine in that predetermined region; the first relative concentration of chlorine in the perovskite layer is M0, where 0 < M0 ≤ 6%; The perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface is the incident light side; the thickness of the perovskite layer is denoted as H; there is a first region with a thickness of 5nm to 10nm extending 20nm from the first surface along the thickness direction of the perovskite layer toward the interior of the perovskite layer; there are second regions with a thickness of 5nm to 10nm extending 10nm from H / 2 of the perovskite layer along the thickness direction of the perovskite layer toward the first surface and the second surface, respectively. The first percentage of chlorine is defined as the ratio of the amount of chlorine in a predetermined region of the perovskite layer to the total amount of chlorine in the perovskite layer. The first percentage of chlorine in the first region is greater than the first percentage of chlorine in the second region.

33. The preparation method according to claim 31 or 32, characterized in that, The perovskite precursor solution containing non-chlorine monovalent anions also includes a second metal chloride; Optionally, the second metal chloride includes PbCl2; Optionally, the molar percentage of chlorine in the second metal chloride relative to the non-chlorine monovalent anion is 0.05% to 9%.

34. The preparation method according to any one of claims 31 to 33, characterized in that, It meets one or more of the following characteristics: (1) The first metal chloride includes PbCl2; (2) The molar percentage of chlorine in the first metal chloride relative to the non-chlorine monovalent anion is 0.001%~0.05%, and can be selected as 0.001%~0.02%; (3) The second annealing includes: performing gradient annealing at temperatures T1 and T2, where T1 > T2; Optionally, temperature T1 is 150℃~170℃, and temperature T2 is 100℃~120℃; Optionally, the annealing time at temperature T1 is 2 min to 5 min; the annealing temperature at temperature T2 is 5 min to 15 min.

35. A photovoltaic module, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 30 and the solar cells prepared by the preparation method according to any one of claims 31 to 34.

36. An electrical appliance, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 30 and the solar cells prepared by the preparation method according to any one of claims 31 to 34.

37. A power generation device, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 30 and the solar cells prepared by the preparation method according to any one of claims 31 to 34.

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