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

Abstract

The invention relates to a solar cell and a preparation method thereof, a photovoltaic module, a power utilization device and a power generation device. The solar cell comprises a first electrode, a first hole transport layer, a perovskite layer and a second electrode, the first hole transport layer and the perovskite layer are stacked between the first electrode and the second electrode, and the first hole transport layer is located between the first electrode and the perovskite layer; the first hole transport layer comprises a sodium element; a first region close to the perovskite layer and a second region close to the first electrode exist in the first hole transport layer; the first area is located between the first surface and the second area; the ratio of the first substance amount of the sodium element in the first region is greater than the ratio of the first substance amount of the sodium element in the second region. The solar cell has good photoelectric conversion efficiency.

Description

Technical Field

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

[0002] Solar cells are optoelectronic devices that convert light energy into electrical energy using a photoelectric conversion mechanism. With the development of solar cells, perovskite solar cells, as an emerging photovoltaic technology, have made significant progress in recent years in terms of photoelectric conversion efficiency, stability, and environmental friendliness. Perovskite solar cells utilize the photoelectric conversion mechanism of perovskite crystalline materials to convert solar energy into electrical energy. With their high photoelectric conversion efficiency, excellent material properties, simple fabrication process, low cost, flexibility, and lightweight characteristics, they have shown great development potential in the photovoltaic field. However, their photoelectric conversion efficiency still needs further improvement. Summary of the Invention

[0003] In view of the above problems, this application provides a solar cell with improved photoelectric conversion efficiency, 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 first electrode, a first hole transport layer, a perovskite layer and a second electrode, wherein the first hole transport layer and the perovskite layer are stacked between the first electrode and the second electrode, and the first hole transport layer is located between the first electrode and the perovskite layer.

[0005] The first hole transport layer includes sodium.

[0006] The first hole transport layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface faces the perovskite layer, and the second surface faces the first electrode; a first region with a thickness of 1nm to 3nm exists within a region extending 5nm from the first surface into the first hole transport layer along the thickness direction, and a second region with a thickness of 1nm to 3nm exists within a region extending 5nm from the second surface into the first hole transport layer along the thickness direction; the first region is located between the first surface and the second region;

[0007] The first proportion of sodium in the preset region is defined as the ratio of the amount of sodium in the preset region to the total amount of sodium in the first hole transport layer; the first proportion of sodium in the first region is greater than the first proportion of sodium in the second region.

[0008] Introducing sodium into the first hole transport layer improves its conductivity, facilitates carrier transport, reduces non-radiative recombination, and enhances the photoelectric conversion efficiency of the solar cell. Furthermore, since hole carriers primarily accumulate near the first surface of the first hole transport layer, adjusting the sodium content in the first region to be greater than that in the second region can simultaneously improve the conductivity of both regions, with a greater improvement in the first region. This facilitates the timely extraction and transport of hole carriers accumulated at the interface to the first electrode, thereby improving the photoelectric conversion efficiency of the solar cell.

[0009] In some embodiments, the average molar volume concentration of sodium in the first hole transport layer is 0.0001 mmol / cm³. 3 ~0.002mmol / cm 3 The value can be set to 0.0001 mmol / cm. 3 ~0.001mmol / cm 3 .

[0010] Introducing sodium into the first hole transport layer can improve its conductivity, facilitate carrier transport, reduce non-radiative recombination, and improve photoelectric conversion efficiency. Controlling the sodium content in the first hole transport layer within the aforementioned range can regulate and prevent excessive sodium from interfering with the perovskite lattice, slowing the transformation of the perovskite crystal into a non-photoactive phase. This helps improve the stability of the solar cell, thereby simultaneously improving its photoelectric conversion efficiency and long-term lifespan.

[0011] In some embodiments, one or more of the following features are satisfied:

[0012] (1) The first substance of sodium in the first region has a first substance content of 10%~45%, which can be selected as 10%~25%;

[0013] (2) The first substance of sodium in the second region has a mass percentage of 4% to 25%, which can be 4% to 11%.

[0014] This can simultaneously improve the conductivity of the first and second regions, and regulate the formation of an internal electric field between the first and second regions, which helps to extract and transport the accumulated hole carriers to the electrodes in a timely manner, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0015] In some embodiments, the direction from the first surface to the second surface in the thickness direction of the first hole transport layer is denoted as the Z1 direction, and the first substance proportion of sodium element in the first hole transport layer generally decreases in the Z1 direction.

[0016] Hole carriers mainly accumulate near the first surface of the first hole transport layer. Therefore, adjusting the proportion of sodium in the first hole transport layer in the Z1 direction generally shows a decreasing trend, which is beneficial for timely extraction and transport of hole carriers accumulated at the interface to the first electrode, thereby improving the photoelectric conversion efficiency of the solar cell.

[0017] In some embodiments, the first hole transport layer includes nickel oxide; the molar percentage of sodium in a preset region of the first hole transport layer relative to nickel in the preset region is denoted as the first relative concentration of sodium in the preset region; the first relative concentration of sodium in the first region is greater than the first relative concentration of sodium in the second region.

[0018] Optionally, the first relative concentration of sodium in the first hole transport layer is 0.1% to 3%;

[0019] Optionally, the first relative concentration of sodium in the first region is 0.5% to 5%;

[0020] Optionally, the first relative concentration of sodium in the second region is 0.05% to 2%.

[0021] Nickel oxide, as a hole transport material in the first hole transport layer, possesses excellent chemical and thermal stability, low optical loss, good process compatibility, and low cost, which is beneficial for improving the photoelectric conversion efficiency and long-term lifespan of solar cells. Controlling the relative concentration of sodium in the aforementioned preset regions helps improve the conductivity of the corresponding regions, enabling timely extraction and transport of accumulated charge carriers to the electrodes, thereby improving photoelectric conversion efficiency and long-term lifespan.

[0022] In some embodiments, the perovskite layer comprises a first perovskite material and sodium; the first perovskite material comprises an X1 element, wherein the X1 element is selected from halogens and pseudohalogens;

[0023] The perovskite layer has a third surface and a fourth surface that are opposite to each other in the thickness direction. The third surface faces the first hole transport layer, and the fourth surface faces the second electrode. A third region with a thickness of 5 nm to 10 nm exists from the third surface to a region extending 20 nm toward the interior of the perovskite layer. A fourth region with a thickness of 5 nm to 10 nm exists from the fourth surface to a region extending 20 nm toward the interior of the perovskite layer.

[0024] The molar percentage of sodium in a preset region relative to the X1 element in the preset region in the perovskite layer is denoted as the second relative concentration of sodium in the preset region.

[0025] The second relative concentration of sodium in the third region is greater than the second relative concentration of sodium in the fourth region;

[0026] Optionally, the X1 element exists in the form of X1 ions.

[0027] At this point, the introduction of sodium into the perovskite layer can passivate grain boundaries and bulk defects in the perovskite layer, and inhibit the migration of X1 elements through electrostatic interactions with the perovskite material, thereby improving the photoelectric conversion efficiency and stability of the solar cell. Furthermore, by adjusting the relative concentration of sodium in the third region to be greater than that in the fourth region, the conductivity between the third and fourth surfaces can be tuned, resulting in better conductivity on the side of the perovskite layer closer to the first hole transport layer. This promotes carrier transport towards the interface where the fourth surface is located, thus improving the photoelectric conversion efficiency and long-term operational life of the solar cell.

[0028] In some embodiments, the second relative concentration of sodium in the perovskite layer is 0.5% to 7%, optionally 0.5% to 5%. This can passivate defects in the perovskite layer and suppress the migration of X1 elements. Furthermore, controlling the sodium content can reduce the risk of lattice distortion, balance carrier transport, and ensure the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0029] In some embodiments, the second relative concentration of sodium in the third region is 1.5% to 11%, optionally 1.5% to 6%. This balances carrier transport and maintains the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0030] In some embodiments, the second relative concentration of sodium in the fourth region is 0.3% to 3.5%, optionally 0.3% to 2.5%. This balances carrier transport and maintains the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0031] In some embodiments, the proportion of sodium in a predetermined region of the perovskite layer relative to the total amount of sodium in the perovskite layer is denoted as the second proportion of sodium in that predetermined region. The direction from the third surface to the fourth surface in the thickness direction of the perovskite layer is denoted as the Z2 direction, and the second proportion of sodium in the perovskite layer generally decreases along the Z2 direction. This balances carrier transport and maintains the stability of the perovskite layer, improving the photoelectric conversion efficiency and long-term lifespan of the solar cell.

[0032] In some embodiments, the second substance of sodium in the third region accounts for 3% to 5% of the total mass. This can balance carrier transport and take into account the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0033] In some embodiments, the second substance of sodium in the fourth region accounts for 0.5% to 2.5% of the total mass. This balances carrier transport and maintains the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term lifespan of the solar cell.

[0034] In some embodiments, the average molar volume concentration of sodium in the perovskite layer is 0.00001 mmol / cm³. 3 ~0.0001mmol / cm 3 .

[0035] Therefore, on the one hand, it can passivate defects in the perovskite layer and suppress the migration of X1 elements. On the other hand, it can reduce the risk of lattice distortion by controlling the sodium content, balance the transport of charge carriers, and take into account the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of solar cells.

[0036] In some embodiments, the sodium element exists in the form of sodium ions.

[0037] In some embodiments, the solar cell further includes a glass substrate layer disposed on the side of the first electrode away from the perovskite layer. The glass substrate layer has a smooth surface, good transparency, good stability, and low cost, which is beneficial for improving overall performance while also considering cost.

[0038] In some embodiments, the glass substrate layer includes a sodium-containing glass layer and a sodium-blocking layer; the sodium-blocking layer is disposed between the sodium-containing glass layer and the first electrode;

[0039] Optionally, the sodium-blocking layer comprises at least one of graphene, molybdenum sulfide, silicon dioxide, and metal oxides;

[0040] Further optionally, the metal oxide includes at least one of titanium oxide, zirconium oxide, aluminum oxide, tin oxide, and molybdenum oxide;

[0041] Further optionally, the sodium-blocking layer further includes a downconversion material; the downconversion material includes at least one of rare earth complexes and inorganic substances.

[0042] Sodium in sodium-containing glass layers can migrate into battery module structures such as perovskite layers. By setting sodium-blocking layers, the migration of sodium can be blocked, reducing the amount of sodium migration and effectively controlling the amount of sodium migration, so as to balance the photoelectric conversion efficiency and stability of solar cells.

[0043] Furthermore, silicon dioxide exhibits good physical barrier properties, effectively blocking sodium elements. Graphene and molybdenum sulfide also exert their blocking effect through size exclusion. Metal oxides, on the other hand, can form dense crystalline films, creating lattice barriers that significantly reduce sodium migration under extreme conditions such as high-intensity light and high heat, thereby effectively controlling the amount of sodium migration. These downconversion materials can convert 200–400 nm ultraviolet light into longer-wavelength visible light. This not only increases the absorbable light of the perovskite layer but also reduces the damage of ultraviolet light to the functional layers and perovskite layer of solar cells, improving the cell's UV lifespan.

[0044] In some embodiments, the glass substrate layer further includes a buffer layer; the buffer layer is disposed on the side of the sodium-blocking layer facing the first electrode;

[0045] Optionally, the buffer layer comprises at least one of semiconductor metal oxides;

[0046] Further optionally, the semiconductor metal oxide includes at least one of tin oxide and indium oxide.

[0047] The buffer layer isolates the first electrode from the sodium-blocking layer, preventing damage to the sodium-blocking layer during solar cell fabrication. This allows the sodium-blocking layer to effectively prevent excessive sodium migration into the solar cell, thus achieving effective control over the amount of sodium migration. Furthermore, semiconductor metal oxides can form dense materials that physically block sodium while also possessing a certain degree of conductivity, thus balancing sodium blocking effectiveness with conductivity.

[0048] In some embodiments, one or more of the following features are satisfied:

[0049] (1) The thickness ratio of the buffer layer to the sodium-blocking layer is (0.3~3.5):1;

[0050] (2) The thickness of the sodium barrier layer is 10 nm to 100 nm.

[0051] This helps to balance sodium blocking effect, light transmittance, and conductivity.

[0052] In some embodiments, the solar cell has a first channel region; the first channel region penetrates the first electrode and extends into the glass substrate layer; the depth of the first channel region in the glass substrate layer is less than the thickness of the buffer layer. The aforementioned first channel region does not damage the sodium-blocking layer, which helps the sodium-blocking layer effectively block sodium elements, significantly reducing the migration of sodium elements and achieving effective control over the migration of sodium elements.

[0053] 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.

[0054] When solar cells are multi-junction solar cells, they are beneficial for improving the utilization rate of incident light, while also possessing the aforementioned advantages of high photoelectric conversion efficiency and high device stability. Multi-junction solar cells can be monolithic integrated tandem solar cells or mechanically tandem solar cells, offering flexibility in form and a wide range of applications.

[0055] 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.

[0056] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0057] In some embodiments, the multi-junction solar cell includes a first electrode, a first hole transport layer, a perovskite layer, an interconnect layer, a second light absorption layer, and a second electrode stacked together; wherein the carrier recombination layer or the tunneling layer is located between the perovskite layer and the second light absorption layer; the first electrode is located on the side of the first hole 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 interconnect layer.

[0058] Thus, in a multi-junction solar cell, the two cells are connected by an interconnect layer to achieve current matching between the two cells. This results in a relatively smaller size, the ability to absorb light of different wavelengths, a wider absorption spectrum range, and improved photoelectric conversion efficiency. In some embodiments, a hole transport layer is provided between the first electrode and the perovskite layer.

[0059] In some embodiments, the multi-junction solar cell includes a first electrode, a first hole 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, and 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 hole 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. In some embodiments of this application, a hole transport layer is disposed between the first electrode and the perovskite layer.

[0060] In some embodiments, the perovskite layer is incorporated into the inverse or formal structure of the solar cell.

[0061] The aforementioned implementation methods can be universally applied to solar cells with conventional or inverted structures, thereby improving photoelectric conversion efficiency and device stability.

[0062] Secondly, this application provides a method for preparing a solar cell, comprising the following steps:

[0063] A first material and a second material are sequentially deposited on the first electrode and then annealed to form a first hole transport layer; wherein the second material contains sodium.

[0064] A perovskite layer is formed on the first hole transport layer, and a second electrode is formed on the perovskite layer;

[0065] The first hole transport layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface faces the perovskite layer, and the second surface faces the first electrode; a first region with a thickness of 1nm to 3nm exists within a region extending 5nm from the first surface into the first hole transport layer along the thickness direction, and a second region with a thickness of 1nm to 3nm exists within a region extending 5nm from the second surface into the first hole transport layer along the thickness direction; the first region is located between the first surface and the second region;

[0066] The proportion of sodium in the first substance in the first region is greater than that in the second region.

[0067] By sequentially depositing a first material and a second material containing sodium on the first electrode, and by allowing the sodium to migrate naturally from a high concentration to a low concentration during the annealing process, the distribution trend of sodium in the first hole transport layer can be adjusted so that the proportion of sodium in the first region of the first hole transport layer is greater than that in the second region, thus forming the aforementioned first hole transport layer.

[0068] Furthermore, introducing an appropriate amount of sodium into the first hole transport layer and making it form the above-mentioned distribution trend can improve the conductivity of the first hole transport layer, which is beneficial to the transport of charge carriers, reduces non-radiative recombination, and thus improves the photoelectric conversion efficiency of the solar cell.

[0069] In some embodiments, one or more of the following features are satisfied:

[0070] (1) In the second material, the mass percentage of sodium is 1wt%~15wt%, and can be selected as 5wt%~10wt%;

[0071] (2) The ratio of the thickness of the first material to the thickness of the second material is (0.1~3):1, which can be (0.5~2):1;

[0072] (3) The thickness of the second material deposited is 3nm~20nm, and can be selected as 5nm~15nm;

[0073] (4) The annealing conditions include: annealing temperature of 150℃~300℃ and annealing time of 5min-20min.

[0074] Controlling the ratio of the thickness of the first deposited material to the thickness of the second deposited material, as well as the thickness of the second deposited material, helps to regulate the distribution trend of sodium in the first hole transport layer, thereby improving the photoelectric conversion efficiency of the solar cell. The aforementioned annealing conditions, on the other hand, promote the migration of sodium in the first hole transport layer, causing it to form a targeted distribution trend, improving the conductivity of the first hole transport layer, facilitating carrier transport, reducing non-radiative recombination, and thus improving the photoelectric conversion efficiency of the solar cell.

[0075] In some embodiments, the fabrication method further includes the step of fabricating a first electrode on a glass substrate, specifically including:

[0076] A glass substrate layer is provided, wherein the glass substrate includes a stacked sodium-containing glass layer, a sodium-blocking layer and a buffer layer, the sodium-blocking layer being located between the sodium-containing glass layer and the buffer layer, and the buffer layer being close to the first electrode;

[0077] The first electrode is disposed on the surface of the sodium-blocking layer of the glass substrate, and a first channel region is etched on the first electrode; the first channel region penetrates the first electrode and extends into the glass substrate; the depth of the first channel region in the glass substrate is less than the thickness of the buffer layer.

[0078] Sodium in the sodium-containing glass layer can migrate to functional layers such as the perovskite layer. A sodium-blocking layer can be used to prevent this migration, reducing the amount of sodium that migrates and effectively controlling its amount. However, during the etching of the first channel region, the first electrode needs to be completely severed to separate different cell units, which easily damages the sodium-blocking layer. This allows a large amount of sodium from the sodium-containing glass layer to migrate to the perovskite layer and other functional layers through the damaged areas. A buffer layer can isolate the first electrode from the sodium-blocking layer, making the sodium-blocking layer less susceptible to damage and effectively preventing sodium migration, thus achieving effective control over the amount of sodium migration.

[0079] Thirdly, this application provides a photovoltaic module, including at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect. The above-mentioned photovoltaic module has improved photoelectric conversion efficiency and long-term stability.

[0080] Fourthly, this application provides an electrical device comprising at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect.

[0081] The aforementioned electrical devices have improved photoelectric conversion efficiency and long-term stability.

[0082] Fifthly, this application provides a power generation device, including at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect.

[0083] The aforementioned power generation device has improved photoelectric conversion efficiency and long-term stability. Attached Figure Description

[0084] 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:

[0085] Figure 1 This is a schematic diagram of a solar cell according to an embodiment of the present application, including a first electrode, a first hole transport layer, a perovskite layer, and a second electrode.

[0086] Figure 2 This is a schematic diagram of a solar cell according to an embodiment of the present application, which includes a first hole transport layer; the first hole transport layer includes a first region, a second region, a first surface and a second surface;

[0087] Figure 3 This is a schematic diagram of a solar cell according to an embodiment of the present application, which includes a perovskite layer; the perovskite layer includes a third region, a fourth region, a third surface, and a fourth surface;

[0088] Figure 4 A schematic diagram of a solar cell according to an embodiment of this application; including a substrate layer, a first electrode, a first hole transport layer, a perovskite layer, a second transport layer, and a second electrode; the first electrode is the light-incident side electrode;

[0089] Figure 5 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 hole transport layer, a perovskite layer, a second transport layer, a second electrode, a first channel region, a second channel region, a third channel region, a sodium-containing glass layer, a sodium-blocking layer, and a buffer layer;

[0090] Figure 6 This is a SEM image of the glass substrate and the first electrode in a solar cell according to an embodiment of this application.

[0091] Figure 7 These are the qualitative analysis results of the TOF-SIMs of the solar cell module of Embodiment 1 of this application;

[0092] Figure 8This is a graph showing the relationship between the first molar percentage of sodium element in the first hole transport layer and the test time in Embodiment 1 of this application.

[0093] Figure 9 This is a graph showing the relationship between the second relative concentration of sodium in the perovskite layer of Example 1 of this application and the test time.

[0094] Explanation of reference numerals in the attached figures: 100 is a perovskite solar cell; 110 is a substrate layer; 120 is a first electrode; 130 is a first hole transport layer; 140 is a perovskite layer; 150 is a first electron 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; 111 is a sodium-containing glass layer; 112 is a sodium-blocking layer; 113 is a buffer layer; 1301 is a first region; 1302 is a second region; 1303 is a first surface; 1304 is a second surface; 1401 is a third region; 1402 is a fourth region; 1403 is a third surface; 1404 is a fourth surface.

[0095] It should be noted that, Figure 2-3 The dashed lines marked within the first hole transport layer or perovskite layer only indicate the positions of the first to fourth regions on both sides of the thickness direction of the first hole transport layer or perovskite layer, but do not mean that the marked first region forms an interface of different phases with the adjacent parts within the first hole transport layer or perovskite layer; in some embodiments, the phases on both sides shown by the dashed lines are continuously distributed. Figure 2 In the middle Z, the thickness direction of the first hole transport layer is represented. Figure 3 In the middle Z, the thickness direction of the perovskite layer is indicated. Detailed Implementation

[0096] 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.

[0097] 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.

[0098] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0099] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0100] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0101] 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.

[0102] 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).

[0103] 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.

[0104] 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.

[0105] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," 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," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0106] 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".

[0107] 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.

[0108] In some embodiments of this application, the electron transport layer is capable of extracting and transporting electrons and blocking the passage of free holes.

[0109] In some embodiments of this application, the hole transport layer is capable of extracting and transporting holes and blocking the passage of free electrons.

[0110] In this application, unless otherwise specified, "charge carrier" can be an electron or a hole. "Carrier pair" refers to an electron-hole pair.

[0111] 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 sodium 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 of that region can be calculated, which is the relative concentration.

[0112] 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.

[0113] The content of elements or ions in whole-layer structures such as perovskite layers or transport layers 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.

[0114] In this application, the percentage of sodium in a specific region refers to the percentage of sodium in the structural layer containing that specific region, relative to the total amount of sodium in that structural layer. Specifically, the percentage of sodium in the specific region is calculated by taking the total amount of sodium in the structural layer as 100%. For example, based on the total amount of sodium in the first hole transport layer, the percentage of sodium in the first region = (amount of sodium in the first region / total amount of sodium in the first hole transport layer) × 100%.

[0115] In this application, the average molar volume concentration of sodium refers to the amount of sodium moles per unit volume, which is obtained by dividing the number of sodium moles in the measurement area by the total volume of the measurement area, and is expressed in mmol / cm³. 3 .

[0116] It should be noted that the aforementioned molar percentage, first relative concentration of sodium, second relative concentration of sodium, molar percentage of sodium, and average molar volume concentration of sodium can be obtained by analyzing the complete 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 region 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 the Determination of Standard Reference Materials" (JJF1343-2012).

[0117] In this application, the thickness direction of the first hole transport layer or perovskite layer is indicated by the Z direction. Typically, the first and second surfaces of the hole transport layer are perpendicular or approximately perpendicular to the Z direction; the third and fourth surfaces of the perovskite layer are perpendicular or approximately perpendicular to the Z direction.

[0118] In this application, "overall downward trend" or "overall upward trend" means that the relative concentration of elements can fluctuate to a certain extent, and does not exclude the occurrence of changes opposite to the overall trend in local areas. 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.

[0119] Perovskite solar cells are devices that convert solar energy into electrical energy using the photoelectric conversion mechanism of perovskite crystalline materials. With their high photoelectric conversion efficiency, excellent material properties, simple fabrication process, low cost, flexibility, and lightweight characteristics, they have shown great development potential in the photovoltaic field. However, the photoelectric conversion efficiency of solar cells still needs further improvement.

[0120] Research has found that, in order to meet the energy level matching between the perovskite layer and the electrode, the hole transport layer needs to be made of a wide bandgap material (e.g., >3 eV). Such materials have low intrinsic carrier concentration and poor conductivity, which makes it easy for carriers to accumulate at the interface between the perovskite layer and the hole transport layer due to the difference in migration rate, increasing the probability of nonradiative recombination and limiting the photoelectric conversion efficiency of solar cells.

[0121] Based on this, this application provides a solar cell with improved photoelectric conversion efficiency, a method for preparing the same, as well as an electrical device and a power generation device.

[0122] In some embodiments of the first aspect of this application, a solar cell is provided, including a first electrode, a first hole transport layer, a perovskite layer, and a second electrode. The first hole transport layer and the perovskite layer are stacked between the first electrode and the second electrode, with the first hole transport layer located between the first electrode and the perovskite layer. The first hole transport layer includes sodium. The first hole transport layer has a first surface and a second surface that are opposite to each other in the thickness direction. The first surface faces the perovskite layer, and the second surface faces the first electrode. A first region with a thickness of 1 nm to 3 nm exists from the first surface to a region extending 5 nm toward the interior of the first hole transport layer, and a second region with a thickness of 1 nm to 3 nm exists from the second surface to a region extending 5 nm toward the interior of the first hole transport layer. The first region is located between the first surface and the second region. Based on the total amount of sodium in the first hole transport layer, the proportion of sodium in the first region is greater than the proportion of sodium in the second region.

[0123] The first hole transport layer, needing to meet the overall energy level matching requirements of the solar cell, typically employs hole transport materials with a large band gap. However, hole transport materials with excessively large band gaps have relatively poor conductivity, causing charge carriers to easily accumulate at the interface between the perovskite layer and the first hole transport layer due to differences in migration rates. This increases the probability of non-radiative recombination and limits the photoelectric conversion efficiency. Introducing sodium into the first hole transport layer can improve its conductivity, facilitating carrier transport, reducing non-radiative recombination, and improving the photoelectric conversion efficiency of the solar cell. Furthermore, since hole carriers mainly accumulate near the first surface of the first hole transport layer, adjusting the proportion of sodium in the first region to be greater than that in the second region can simultaneously improve the conductivity of both regions, with a greater improvement in the conductivity of the first region. This facilitates the timely extraction and transport of hole carriers accumulated at the interface to the first electrode, improving the photoelectric conversion efficiency of the solar cell. It is understandable that sodium can exist in the form of sodium ions.

[0124] like Figure 1As shown, a solar cell 100 according to one embodiment of this application includes a first electrode 120, a first hole transport layer 130, a perovskite layer 140, and a second electrode 160; as Figure 2 As shown, the first hole transport layer 130 includes a first region 1301, a second region 1302, a first surface 1303, and a second surface 1304. The first surface 1303 faces the perovskite layer 140. The first region 1301 is close to the first surface 1303. The first region 1301 may or may not include the first surface 1303, representing a specific region of the first hole transport layer 130 near or on the first surface. The second surface 1304 faces the first electrode 120. The second region 1302 is close to the second surface 1304. The second region 1302 may or may not include the second surface 1304, representing a specific region of the first hole transport layer 130 near or on the second surface.

[0125] In some embodiments of this application, the average molar volume concentration of sodium in the first hole transport layer is 0.0001 mmol / cm³. 3 ~0.002mmol / cm 3 The value can be set to 0.0001 mmol / cm. 3 ~0.001mmol / cm 3 It can be 0.0001 mmol / cm 3 0.0002 mmol / cm 3 0.0004 mmol / cm 3 0.0006 mmol / cm 3 0.0008 mmol / cm 3 0.0009 mmol / cm 3 0.001 mmol / cm 3 0.0012 mmol / cm 3 0.0014 mmol / cm 3 0.0016 mmol / cm 3 0.0018 mmol / cm 3 0.002 mmol / cm 3 wait.

[0126] Introducing sodium into the first hole transport layer can improve its conductivity, facilitate carrier transport, reduce non-radiative recombination, and improve photoelectric conversion efficiency. Controlling the sodium content in the first hole transport layer within the aforementioned range can regulate and prevent excessive sodium from interfering with the perovskite lattice, slowing the transformation of the perovskite crystal into a non-photoactive phase. This helps improve the stability of the solar cell, thereby simultaneously improving its photoelectric conversion efficiency and long-term lifespan.

[0127] In some embodiments of this application, the proportion of sodium in the first region, based on the total amount of sodium in the first hole transport layer, is 10% to 45%, optionally 10% to 25%, such as 10%, 12%, 15%, 17%, 19%, 20%, 22%, 24%, 25%, 30%, 35%, 40%, 45%, etc.; the proportion of sodium in the second region, based on the total amount of sodium in the first hole transport layer, is 4% to 25%, optionally 4% to 11%, such as 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 15%, 20%, 25%. This simultaneously improves the conductivity of both the first and second regions and regulates the formation of an internal electric field between them, facilitating the timely extraction and transport of accumulated hole carriers to the electrodes, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0128] In some embodiments of this application, the direction from the first surface to the second surface in the thickness direction of the first hole transport layer is denoted as the Z1 direction, and the first substance proportion of sodium element in the first hole transport layer generally shows a decreasing trend in the Z1 direction.

[0129] Hole carriers mainly accumulate near the first surface of the first hole transport layer. Therefore, adjusting the proportion of sodium in the first hole transport layer in the Z1 direction generally shows a decreasing trend, which is beneficial for timely extraction and transport of hole carriers accumulated at the interface to the first electrode, thereby improving the photoelectric conversion efficiency of the solar cell.

[0130] It is understood that the first hole transport layer includes a hole transport material. Without limitation, the hole transport material in the first hole transport layer may include, but is not limited to, one or more of the following materials and their derivatives: hole transport organic materials and hole transport inorganic materials.

[0131] 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).

[0132] In some embodiments, the first hole transport layer includes nickel oxide; the molar percentage of sodium in a predetermined region of the first hole transport layer relative to nickel in that predetermined region is denoted as the first relative concentration of sodium in that predetermined region; the first relative concentration of sodium in the first region is greater than the first relative concentration of sodium in the second region. Nickel oxide, as the hole transport material of the first hole transport layer, possesses excellent chemical and thermal stability, low optical loss, good process compatibility, and low cost, which is beneficial for improving the photoelectric conversion efficiency and long-term operating life of solar cells. Controlling the relative concentration of sodium in the predetermined regions helps improve the conductivity of the corresponding regions, enabling timely extraction and transport of accumulated charge carriers to the electrodes, thereby improving photoelectric conversion efficiency and long-term operating life.

[0133] In some embodiments of this application, the first relative concentration of sodium in the first hole transport layer is 0.1% to 3%, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.

[0134] In some embodiments of this application, the first relative concentration of sodium in the first region is 0.5% to 5%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0135] In some embodiments of this application, the first relative concentration of sodium in the second region is 0.05% to 2%, for example, 0.05%, 0.1%, 0.15%, 2%, etc.

[0136] In some embodiments of this application, the first relative concentration of sodium in the first hole transport layer is 0.1% to 3%, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.; the first relative concentration of sodium in the first region is 0.5% to 5%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.; and the first relative concentration of sodium in the second region is 0.05% to 2%, for example, 0.05%, 0.1%, 0.15%, 2%, etc. As an example, the first relative concentration of sodium in the first hole transport layer is 1.00%, the first relative concentration of sodium in the first region is 1.66%, and the first relative concentration of sodium in the second region is 0.67%.

[0137] In some embodiments of this application, the thickness of the first hole transport layer is 10nm to 100nm. For example, the thickness of the hole transport layer can be 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, such as 10nm to 30nm, 30nm to 50nm, 40nm to 80nm, 60nm to 100nm, etc.

[0138] In some embodiments of this application, the perovskite layer includes a perovskite material and sodium; the perovskite material includes an X1 element, which is selected from halogens and pseudohalogens; the perovskite layer has a third surface and a fourth surface that are opposite to each other in the thickness direction, the third surface facing the first hole transport layer and the fourth surface facing the second electrode; a third region with a thickness of 5nm to 10nm exists in a region extending 20nm from the third surface toward the interior of the perovskite layer, and a fourth region with a thickness of 5nm to 10nm exists in a region extending 20nm from the fourth surface toward the interior of the perovskite layer; the molar percentage of sodium in a predetermined region relative to the X1 element in that predetermined region is denoted as the second relative concentration of sodium in that predetermined region; the second relative concentration of sodium in the third region is greater than the second relative concentration of sodium in the fourth region.

[0139] At this point, the introduction of sodium into the perovskite layer can passivate grain boundaries and bulk defects in the perovskite layer, and inhibit the migration of X1 element through electrostatic interactions with the perovskite material, thereby improving the photoelectric conversion efficiency and stability of the solar cell. Furthermore, the third surface of the perovskite layer is the interface with the first hole transport layer. Due to the poor conductivity of the first hole transport layer, an imbalance in carrier transport exists between the third and fourth surfaces. The third region cannot effectively transport carriers from the fourth region to the electrode in a timely manner. By adjusting the second relative concentration of sodium in the third region to be greater than that in the fourth region, the conductivity between the third and fourth surfaces can be tuned, giving the side of the perovskite layer closer to the first hole transport layer better conductivity. This promotes carrier transport towards the interface of the fourth surface, thereby improving the photoelectric conversion efficiency and long-term lifespan of the solar cell.

[0140] like Figure 3As shown, a solar cell 100 according to an embodiment of this application includes a perovskite layer 140; the perovskite layer 140 includes a third region 1401, a fourth region 1402, a third surface 1403, and a third surface 1404. The third surface 1403 is located on the side of the perovskite layer 140 facing the first hole transport layer 130. The third region 1401 is close to the third surface 1403. The third region 1401 may or may not include the third surface 1403, representing a specific region of the perovskite layer near or on the third surface. The fourth surface 1404 is located on the side of the perovskite layer 140 facing the second electrode 160. The fourth region 1402 is close to the fourth surface 1404. The fourth region 1402 may or may not include the third surface 1404, representing a specific region of the perovskite layer near or on the fourth surface.

[0141] In this application, the perovskite layer includes a first perovskite material. Unless otherwise specified, "first perovskite material" refers to a type of semiconductor material having a crystal structure similar to that of the natural mineral perovskite (CaTiO3). 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, with the anion located at the body center of the octahedron and the second cation located at the six vertices of the octahedron. The first cation fills the voids in the octahedron to achieve charge balance and maintain the stability of the crystal structure; 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].

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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).

[0146] In some embodiments of this application, the perovskite layer includes a first perovskite material having the following general formula:

[0147] [A] a [M] b [X1] c ;

[0148] A includes a first cation, M includes a second cation, and X1 is selected from at least one of halide ions and pseudohalogen ions;

[0149] 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.

[0150] 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.

[0151] 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 perovskite materials can act as X1-position ions.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] Non-limiting examples of monovalent organic cations include (NR) 31 R 32 R 33 R 34 ) + 、(R 31 R 32 N=CR 33 R 34 ) + 、(R 31 R 32 NC(R 35 )=NR 33 R 34 ) + or (R) 31 R 32 NC(NR 35 R 36 )=R 33 R 34 ) + , where R 31 R 32 R 33 R 34 R 35 and R 36 Each is independently selected from H and C. 1-20 Alkyl, aryl, substituted C 1-20 Alkyl or substituted aryl; wherein, C1-20 Alkyl and substituted C 1-20 The "C" in alkyl 1-20 Each alkyl group can be independently selected as C. 1-15 Alkyl, further optionally C 1-10 Alkyl, and further optionally C 1-8 Alkyl, and further optionally C 1-6 Alkyl, and further optionally C 1-4 Alkyl, and further optionally C 1-3 Alkyl, and further optionally methyl. The "aryl" in aryl and substituted aryl groups can each independently be C10. 6-20 Aryl, further optionally C 6-12 Aryl, and further alternatively C 6-10 Aryl, further optionally phenyl or naphthyl, and further optionally phenyl. Substituted C 1-20 In alkyl and substituted aryl groups, each substituent is independently C1. 1-10 Hydrocarbon group, further optionally C 1-6 Alkyl or C 6-10 Aryl, and may further be methyl or phenyl.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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 them.

[0161] 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.

[0162] 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.

[0163] In some embodiments of this application, the molar percentage of bromide anions in the monovalent anions of perovskite materials is 0 to 1.0.

[0164] 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.

[0165] Without limitation, in perovskite-type metal halides, B can be an inorganic cation.

[0166] 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.

[0167] 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.

[0168] In perovskite-type metal halides, X1 can be an inorganic anion, an organic anion, or a mixture of organic and inorganic anions.

[0169] 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.

[0170] 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. - .

[0171] 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). + ).

[0172] In a non-limiting sense, in perovskite metal halides, D can be an inorganic cation, an organic cation, or a mixed organic-inorganic cation.

[0173] 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.

[0174] 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.

[0175] In some embodiments of this application, the second relative concentration of sodium in the perovskite layer is 0.5% to 7%, optionally 0.5% to 5%, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, etc. This balances carrier transport and ensures the stability of both the perovskite layer and the electrodes, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0176] In some embodiments of this application, the second relative concentration of sodium in the third region is 1.5% to 11%, optionally 1.5% to 6%, such as 1.5%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 11%, etc. This balances carrier transport and ensures the stability of the perovskite layer and electrodes, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0177] In some embodiments of this application, the second relative concentration of sodium in the fourth region is 0.3% to 3.5%, optionally 0.3% to 2.5%, such as 0.3%, 0.5%, 0.7%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, etc. This balances carrier transport and ensures the stability of the perovskite layer and electrodes, improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0178] In some embodiments of this application, the proportion of sodium in a predetermined region of the perovskite layer relative to the total amount of sodium in the perovskite layer is denoted as the second proportion of sodium in that predetermined region. The direction from the third surface to the fourth surface in the thickness direction of the perovskite layer is denoted as the Z2 direction, and the second proportion of sodium in the perovskite layer generally decreases in the Z2 direction. This balances carrier transport and takes into account the stability of the perovskite layer and the electrodes, improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0179] In some embodiments of this application, the second substance of sodium in the third region accounts for 3% to 5% of the total content, such as 3%, 3.5%, 4%, 4.5%, 5%, etc. This balances carrier transport and maintains the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0180] In some embodiments of this application, the second substance of sodium in the fourth region accounts for 0.5% to 2.5% of the total content, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, etc. This balances carrier transport and maintains the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of the solar cell.

[0181] In some embodiments of this application, the second molar percentage of sodium in the third region is 3% to 5%, such as 3%, 3.5%, 4%, 4.5%, 5%, etc.; the second molar percentage of sodium in the fourth region is 0.5% to 2.5%, such as 0.5%, 1%, 1.5%, 2%, 2.5%, etc. For example, the molar percentage of sodium in the third region (the region extending 10 to 20 nm from the third surface toward the interior of the perovskite layer) is 3.91%, and the molar percentage of sodium in the fourth region (the region extending 10 to 20 nm from the fourth surface toward the interior of the perovskite layer) is 1.43%.

[0182] In some embodiments, the average molar volume concentration of sodium in the perovskite layer is 0.00001 mmol / cm³. 3 ~0.0001mmol / cm 3For example, 0.00001 mmol / cm 3 0.00002 mmol / cm 3 0.00003 mmol / cm 3 0.00004 mmol / cm 3 0.00005 mmol / cm 3 0.00006 mmol / cm 3 0.00007 mmol / cm 3 0.00008 mmol / cm 3 0.00009mmol / cm 3 0.0001 mmol / cm 3 wait.

[0183] Therefore, on the one hand, it can passivate defects in the perovskite layer and suppress the migration of X1 elements. On the other hand, it can reduce the risk of lattice distortion by controlling the sodium content, balance the transport of charge carriers, and take into account the stability of the perovskite layer, thereby improving the photoelectric conversion efficiency and long-term operating life of solar cells.

[0184] In some embodiments of this application, the solar cell further includes a substrate layer disposed on the side of the first electrode away from the perovskite layer. It is understood that the substrate layer involved in the embodiments or examples of this application may be, but is not limited to, a rigid substrate layer or a flexible substrate layer. Non-limiting examples of rigid substrate layers include glass substrate layers. 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. In some embodiments of this application, the flexible substrate layer may be made of, but is not limited to, organic polymer materials, and may further 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.

[0185] In some embodiments, the substrate layer is a glass substrate layer. Glass substrate layers have a smooth surface, good transparency, good stability, and low cost, which is beneficial for improving overall performance while taking cost into account.

[0186] In some embodiments of this application, the glass substrate layer includes a sodium-containing glass layer and a sodium-blocking layer; the sodium-blocking layer is disposed between the sodium-containing glass layer and the first electrode. Sodium elements in the sodium-containing glass layer can migrate into the battery module structure such as the perovskite layer. By setting the sodium-blocking layer, the migration of sodium elements can be blocked, reducing the amount of sodium migration and effectively controlling the amount of sodium migration, so as to balance the photoelectric conversion efficiency and stability of the solar cell.

[0187] In this application, the sodium-containing glass layer refers to a glass substrate layer containing sodium, and its material includes at least one selected from soda-lime glass, aluminosilicate glass, high-alumina cover glass, and borosilicate glass. In some embodiments of this application, the mass fraction of sodium in the sodium-containing glass layer is 12wt% to 16wt%, for example, 12wt%, 12.5wt%, 13wt%, 13.5wt%, 14wt%, 14.5wt%, 15wt%, 15.5wt%, 16wt%, etc. The thickness of the sodium-containing glass layer can be 0.8mm to 4mm, for example, 0.8mm, 1mm, 2mm, 3mm, 4mm, etc.

[0188] In this application, the sodium barrier layer refers to a barrier layer that prevents the migration of sodium elements, which can prevent excessive migration of sodium elements from the sodium-containing glass layer to functional layers such as the perovskite layer.

[0189] In some embodiments of this application, the sodium-blocking layer includes at least one of graphene, molybdenum sulfide, silicon dioxide, and metal oxides; the metal oxides include at least one of titanium oxide, zirconium oxide, aluminum oxide, tin oxide, and molybdenum oxide. Silica has good physical barrier properties and can block sodium elements through physical barriers; graphene and molybdenum sulfide can exert their blocking effect through size exclusion effect; while metal oxides can form a dense crystalline film, forming a lattice barrier, which helps to significantly reduce the migration of sodium elements under extreme conditions such as high intensity light and high heat, thereby achieving effective control of the amount of sodium migration. Understandably, amorphous metal oxides can be used. Amorphous metal oxides have an amorphous structure and no grain boundaries, which can form a continuous and dense barrier layer, effectively inhibiting the penetration and diffusion of sodium ions or sodium metal, and thus improving the sodium-blocking effect.

[0190] In some embodiments of this application, the thickness of the sodium-blocking layer is 10 nm to 100 nm, such as 10 nm, 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, etc. This is beneficial for effectively blocking the migration of sodium elements while taking into account light transmittance and conductivity.

[0191] In some embodiments of this application, the sodium-blocking layer further includes a down-conversion material; the down-conversion material includes at least one of rare earth complexes and inorganic substances. The aforementioned down-conversion material can convert ultraviolet light in the 200-400 nm range into long-wavelength visible light, which helps increase the absorbable light of the perovskite layer and reduces the damage of ultraviolet light to the functional layer and perovskite layer of the solar cell, thereby improving the cell's UV resistance lifetime. As a specific example, the down-conversion material includes LaPO4:Eu 3+ NaYF4:Yb 3+ / Er 3+ NaYF4:Yb 3+ / Tm 3+ At least one of Eu(DBM)3(TPPO)2.

[0192] In some embodiments of this application, the glass substrate layer further includes a buffer layer; the buffer layer is disposed on the side of the sodium-blocking layer facing the first electrode. The buffer layer can isolate the first electrode and the sodium-blocking layer, making the sodium-blocking layer less susceptible to damage during the fabrication of the solar cell, thereby effectively preventing excessive migration of sodium elements into the solar cell and achieving effective control over the amount of sodium migration.

[0193] In some implementations, such as Figure 5 As shown, the glass substrate 110 includes a sodium-containing glass layer 111, a sodium-blocking layer 112, and a buffer layer 113. The sodium-blocking layer is disposed between the sodium-containing glass layer 110 and the first electrode 120; the buffer layer 113 is disposed on the side of the sodium-blocking layer 112 facing the first electrode 120.

[0194] In some embodiments of this application, the buffer layer comprises at least one semiconductor metal oxide; further, the semiconductor metal oxide comprises at least one of tin oxide and indium oxide. Semiconductor metal oxides can form dense materials that can physically block sodium elements, while also possessing a certain degree of conductivity, thus achieving a balance between sodium blocking effect and conductivity.

[0195] In some embodiments of this application, the thickness ratio of the buffer layer to the sodium-blocking layer is (0.3~3.5):1, for example, 0.3:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, etc. This is beneficial for balancing sodium blocking effect, light transmittance, and conductivity.

[0196] In some embodiments of this application, the thickness of the buffer layer is 3nm to 350nm, such as 3nm, 10nm, 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, etc.

[0197] In some embodiments of this application, the solar cell has a first channel region; the first channel region penetrates the first electrode and extends into the glass substrate; the depth of the first channel region in the glass substrate is less than the thickness of the buffer layer. The aforementioned first channel region does not damage the sodium-blocking layer, which helps the sodium-blocking layer effectively block sodium elements, significantly reducing the migration of sodium elements and achieving effective control over the migration of sodium elements.

[0198] In some embodiments, the solar cell further includes a first electron transport layer disposed between the perovskite and the second electrode for extracting and transporting electrons.

[0199] It is understood that the first electron transport layer includes an electron transport material. Non-limitingly, the electron transport material in the first electron transport layer may include, but is not limited to, one or more of the following materials and their derivatives, dopants, 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, aluminum hydroxyquinoline, oxadiazole compounds, quinone compounds, etc.; exemplarily, fullerenes and their derivatives include, but are not limited to, [6,6]-phenyl-C 61 methyl butyrate (PC) 61 BM), [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).

[0200] In some embodiments of this application, the thickness of the first 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.

[0201] 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.

[0202] 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.

[0203] In this application, unless otherwise specified, a "multi-junction solar cell" refers to a solar cell in which two or more cell cells made of semiconductor active materials with different band gaps are stacked together in series optically and / or electrically. Multi-junction solar cells can broaden the absorption spectrum of solar cells, maximizing the conversion of light energy into electrical energy, and also help reduce thermal relaxation losses. Multi-junction solar cell design is an important way to overcome the Shockley-Queisser limit efficiency of single-junction solar cells. A multi-junction solar cell includes at least two cell cells, each cell cell including at least one light-absorbing layer, and each light-absorbing layer has a different band gap.

[0204] 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.

[0205] In this application, unless otherwise specified, "battery cell" and "battery section" have the same meaning and can be used interchangeably.

[0206] In this application, unless otherwise specified, "light-absorbing layer" and "light-absorbing layer" have the same meaning and can be used interchangeably.

[0207] 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.

[0208] When solar cells are multi-junction solar cells, they are beneficial for improving the utilization rate of incident light, while also possessing the aforementioned advantages of high photoelectric conversion efficiency and high device stability. Multi-junction solar cells can be monolithic integrated tandem solar cells or mechanically tandem solar cells, offering flexibility in form and a wide range of applications.

[0209] In some embodiments of this application, the first light-absorbing layer is the aforementioned perovskite layer. The aforementioned perovskite layer can be incorporated into a multi-junction solar cell to improve the photoelectric conversion efficiency and device stability of the multi-junction solar cell.

[0210] 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.

[0211] 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.

[0212] In some embodiments of this application, the interconnect layer includes a carrier recombination layer.

[0213] In some embodiments of this application, the interconnect layer includes a tunneling layer.

[0214] In some embodiments of this application, the second light-absorbing layer and the perovskite layer have different band gaps. Thus, by providing multiple light-absorbing layers with different band gaps, the multi-junction solar cell can effectively absorb light of different wavelengths, broadening the spectral range of absorbed light and improving the photoelectric conversion efficiency of the multi-junction solar cell.

[0215] In some embodiments, the multijunction solar cell is a tandem solar cell.

[0216] 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 (i.e., a second light-absorbing layer), and the second light-absorbing layer and the perovskite layer have different band gaps.

[0217] In this way, by setting up multiple light-absorbing layers with different band gaps, multi-junction solar cells can effectively absorb light of different wavelengths, broaden the spectral range of light absorbed by multi-junction solar cells, and improve the photoelectric conversion efficiency of multi-junction solar cells.

[0218] In some embodiments of this application, the light-absorbing layer (i.e., the second light-absorbing layer) in the second battery cell includes a semiconductor active material (which may be referred to as the second semiconductor active material). The second semiconductor active material includes one or more of the following: a second perovskite material, a silicon-containing semiconductor material, a copper zinc tin sulfide, a copper zinc tin selenide, a copper zinc tin selenide sulfide, a copper indium gallium selenide, a copper indium gallium diselenide, a copper indium selenide, cadmium telluride, gallium arsenide, and organic active materials.

[0219] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0220] In some embodiments of this application, a carrier recombination layer or a tunneling layer is provided between the monolithically integrated battery cells.

[0221] 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.

[0222] In some embodiments of this application, a carrier recombination layer is provided between the first battery cell and the second battery cell.

[0223] 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.

[0224] In some embodiments of this application, an interconnection structure is provided between the first battery cell and the second battery cell.

[0225] In some embodiments of this application, a tunnel junction may be formed between the first battery cell and the second battery cell.

[0226] 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.

[0227] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a first hole 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 hole 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 an improved photoelectric conversion efficiency.

[0228] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a first hole 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 hole 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 unit has its own separate positive and negative electrodes for current extraction, allowing for flexible circuit adjustments.

[0229] 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.

[0230] 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.

[0231] In some embodiments of this application, the tandem solar cell includes a first electrode, a first hole 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 hole 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.

[0232] In some embodiments of this application, the tandem solar cell includes a first electrode, a first hole 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 hole 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.

[0233] 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.

[0234] In some embodiments, the perovskite layer is incorporated into the inverted or conventional structure of the solar cell. The foregoing embodiments can be universally applied to solar cells of both conventional and inverted structures, thereby improving photoelectric conversion efficiency and device stability.

[0235] In some implementations, the bandgap of the perovskite layer (i.e., the first light-absorbing layer) is Eg2, where 1.65 eV ≤ Eg2 ≤ 2.2 eV; the bandgap of the second light-absorbing layer is Eg1, where 1.1 eV ≤ Eg1 ≤ 1.6 eV. This bandgap configuration of the perovskite layer and the second light-absorbing layer effectively absorbs both short-wavelength and long-wavelength light, improving the photoelectric conversion efficiency of the multi-junction solar cell. In this implementation, the cell unit corresponding to the second light-absorbing layer is a narrow-bandgap solar cell, and the cell unit corresponding to the perovskite layer is a wide-bandgap solar cell.

[0236] In some embodiments, the second light-absorbing layer comprises a layer of compounds such as: a second perovskite material, crystalline silicon, an organic active material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, gallium arsenide, or cadmium telluride. These materials can absorb light of different wavelengths with the perovskite layer, thereby broadening the spectral range of light absorption in the multi-junction solar cell and improving its photoelectric conversion efficiency. In some embodiments of this application, the definition of the second perovskite material is the same as that of the first perovskite material, but the composition differs to obtain a second light-absorbing layer with a different bandgap, used to absorb light of different wavelengths with the perovskite layer, broadening the absorption spectral range of the multi-junction solar cell and improving its photoelectric conversion efficiency. Exemplarily, the second light-absorbing layer comprises a second perovskite material, thereby obtaining a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises a crystalline silicon material, thereby obtaining a perovskite-crystalline silicon multi-junction solar cell.

[0237] 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 71 BM, etc.), and non-fullerene acceptors (such as Y6 series materials, indendrothiophene derivatives, BTP series, etc.). Exemplary organic active materials include PM6:Y6 and P3HT:PC. 61 One of BM, D18:BTP-eC9, etc. can be used to obtain multiple types.

[0238] 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.

[0239] 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.

[0240] In some implementations, the first electrode in a multi-junction solar cell is a transparent electrode. This allows light to enter the multi-junction solar cell from the first electrode. Furthermore, the band gap of the second light-absorbing layer is Eg1, 1.1 eV ≤ Eg1 ≤ 1.6 eV; the band gap of the perovskite layer is Eg2, 1.65 eV ≤ Eg2 ≤ 2.2 eV. Thus, light entering from the first electrode first passes through the perovskite layer, where it absorbs short-wavelength light (such as ultraviolet to visible light), and then enters the second light-absorbing layer, where it absorbs longer-wavelength light (such as near-infrared light). This allows for greater utilization of different wavelengths of light, improving the photoelectric conversion efficiency of the multi-junction solar cell. Furthermore, the perovskite layer, acting as the top light-absorbing layer, absorbs ultraviolet-visible light, protecting the second light-absorbing layer, which acts as the bottom light-absorbing layer.

[0241] In other embodiments, the bandgap of the second light-absorbing layer is Eg3, where 1.65 eV ≤ Eg3 ≤ 2.2 eV; and the bandgap of the perovskite layer is Eg4, where 1.1 eV ≤ Eg4 ≤ 1.6 eV. Thus, the bandgap settings of the second light-absorbing layer and the perovskite layer can absorb short-wavelength and long-wavelength light respectively, improving the photoelectric conversion efficiency of the multi-junction solar cell. In this embodiment, the cell unit corresponding to the second light-absorbing layer is a wide-bandgap solar cell, and the cell unit corresponding to the perovskite layer is a narrow-bandgap solar cell.

[0242] In other embodiments, the second light-absorbing layer comprises a third perovskite material. Thus, the resulting multi-junction solar cell is a perovskite-perovskite multi-junction solar cell. In some embodiments of this application, the third perovskite material is defined as the same type as the first perovskite material described above, but with a different composition to obtain a second light-absorbing layer with a different bandgap. This layer is used to absorb light of different wavelengths with the perovskite layer, broadening the absorption spectrum range of the multi-junction solar cell and improving its photoelectric conversion efficiency. Exemplarily, the third perovskite material includes APbI. z Br 3-z The material shown is defined as above, where 0 < z < 3.

[0243] In other embodiments, the second electrode in a multi-junction solar cell is a transparent electrode. This allows light to enter the multi-junction solar cell through the second electrode. Furthermore, the band gap of the second light-absorbing layer is Eg3, 1.65 eV ≤ Eg3 ≤ 2.2 eV; the band gap of the perovskite layer is Eg4, 1.1 eV ≤ Eg4 ≤ 1.6 eV. Thus, light entering from the second electrode first passes through the second light-absorbing layer, which absorbs short-wavelength light (such as ultraviolet to visible light), and then enters the perovskite layer, where it absorbs longer-wavelength light (such as near-infrared light). This allows for greater utilization of different wavelengths of light, improving the photoelectric conversion efficiency of the multi-junction solar cell. Furthermore, the second light-absorbing layer, acting as the top cell's light-absorbing layer, absorbs ultraviolet-visible light, protecting the perovskite layer as the bottom cell's light-absorbing layer.

[0244] In some embodiments, a multi-junction solar cell includes a first electrode, a first hole 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 of the multi-junction solar cell.

[0245] In some embodiments, a multijunction solar cell includes a first electrode, a first hole 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.

[0246] In some implementations, a multijunction solar cell includes a first transport layer, a second transport layer, and a third transport layer.

[0247] In this application, the first transport layer, the second transport layer, and the third transport layer are used to transport the first charge carrier, the second charge carrier, and the third charge carrier, respectively. The first charge carrier is an electron, and one of the second and third charge carriers is an electron and the other is a hole.

[0248] In some embodiments, a multi-junction solar cell includes a first electrode, a first hole transport layer, a perovskite layer, optionally a first transport layer, a carrier recombination layer or a tunneling layer, optionally a second transport layer, a second light-absorbing layer, optionally a third transport layer, and a second electrode, all stacked together. The second transport layer is a hole transport layer for transporting holes, while the first and third transport layers are each independently electron transport layers for transporting electrons. Thus, the first electrode, the first hole transport layer, the perovskite layer, and optionally the first transport layer form a first cell unit, and optionally the second transport layer, the second light-absorbing layer, optionally the third 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. For example, 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.

[0249] In some embodiments of this application, multi-junction solar cells may include all three 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 and improving the performance of the multi-junction solar cell. The corresponding electron transport material and hole transport material are selected as defined in the first electron transport layer and the first hole transport layer, but the specific types may differ from those of the first electron transport layer and the first hole transport layer. The materials of the electron transport layer or hole transport layer corresponding to the first cell unit and the second cell unit may be the same or different.

[0250] In some embodiments, a multi-junction solar cell includes a first electrode, a first hole transport layer, a perovskite layer, a first electron transport layer, a carrier recombination layer or a tunneling layer, optionally a second hole transport layer, a second light absorption layer, optionally a second electron transport layer, and a second electrode, all stacked together.

[0251] 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.

[0252] 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.

[0253] In some implementations, the components of the tunneling layer include, but are not limited to, PEDOT, transparent metal oxides, etc.

[0254] In other embodiments, a multi-junction solar cell includes a first electrode, a first hole 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 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.

[0255] In some embodiments, a multi-junction solar cell includes a first electrode, a first hole transport layer, a perovskite layer, optionally a fourth transport layer, a third electrode, an insulating layer, a fourth electrode, optionally a fifth transport layer, a second light-absorbing layer, optionally a sixth transport layer, and a second electrode stacked together. The fourth transport layer is an electron transport layer for transporting electrons. 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 definition and material selection of the corresponding hole transport layer or electron transport layer are as defined in the first electron transport layer and the first hole transport layer, but the specific types may differ from the selection of the first electron transport layer and the first hole transport layer, which will not be elaborated here. Thus, the first electrode, the first hole transport layer, the perovskite layer, optionally the fourth transport layer, and the third electrode form the first battery cell; the fourth electrode, optionally the fifth transport layer, the second light-absorbing layer, optionally the sixth transport layer, and the second electrode form the second battery cell. The first and second battery cells are electrically isolated by an insulating layer. Each battery cell has two electrodes, for a total of four electrodes. The circuits of the two battery cells are independent of each other, forming a four-terminal multi-junction solar cell. This allows for adjustment of the current in the multi-junction solar cell. For example, the second light-absorbing layer comprises a second perovskite material, resulting in a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises crystalline silicon, resulting in a perovskite-crystalline silicon multi-junction solar cell.

[0256] 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.

[0257] 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.

[0258] 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.

[0259] In this application, the designations “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” 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.

[0260] 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.

[0261] As an example, organic-inorganic hybrid conductive materials include both organic and inorganic conductive components.

[0262] 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.

[0263] 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).

[0264] 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.

[0265] 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.

[0266] 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.

[0267] 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.

[0268] 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.

[0269] 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, buffer layers, and insertion layers, may also be introduced as needed.

[0270] In some embodiments, a solar cell may have an interface modification layer with appropriate energy levels, which can perform one or more functions such as lowering the energy level barrier, promoting energy level matching, improving carrier extraction efficiency, passivating interface defect states, protecting the light-absorbing layer, suppressing the oxidative decomposition of the cell by water molecules and oxygen, improving photoelectric conversion efficiency, and improving device stability. Depending on the location of the interface modification layer, it may include an interface modification layer between the first hole transport layer and the first electrode, an interface modification layer between the first electron transport layer and the second electrode, an interface modification layer between the first hole transport layer and the perovskite layer, and an interface modification layer between the first electron transport layer and the perovskite layer. Materials that can be used for interface modification layers in solar cells may include, but are not limited to, Cu2O, NiO, AZO, and TiO2. 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 hole transport and can also be called a hole blocking layer. Examples of materials for the insertion layer include copper bath (BCP) and tin oxide.

[0271] In some embodiments of this application, the solar cell includes the following stacked structure: a transparent conductive glass substrate layer, a first hole transport layer, a perovskite layer, a first electron transport layer, a hole blocking layer (optional), and a back electrode (the back electrode can be a metal electrode or a transparent conductive electrode).

[0272] 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.

[0273] In some embodiments of this application, the solar cell 100 includes Figure 4 The structure shown includes a substrate layer 110, a first electrode 120, a first hole transport layer 130, a perovskite layer 140, a first electron transport layer 150, and a second electrode 160, arranged sequentially. Further, the structural layers are stacked sequentially as shown.

[0274] In some embodiments of this application, the solar cell includes Figure 5The structure shown (a vertical cross-sectional view of the device) includes a substrate layer 110, a first electrode 120, a first hole transport layer 130, a perovskite layer 140, a first electron transport layer 150, and a second electrode 160, stacked sequentially. Furthermore, the solar cell has three cross-layer channel regions: a first channel region P1, a second channel region P2, and a third channel region P3. Utilizing the channel group formed by the first channel region P1, the second channel region P2, and the third channel region P3, the solar cell is divided into several series-connected sub-devices. Each sub-device includes a first channel region P1, a second channel region P2, and a third channel region P3 arranged sequentially, with the second channel region P2 located between the first channel region and the third channel region P3. The first channel region P1, the second channel region P2, and the third channel region P3 can be connected to the spaced-apart structural layers, thereby forming a circuit between the structural layers of the first electrode and the second electrode. The first channel region P1, the second channel region P2, and the third channel region P3 can each be an independent linear channel region, formed by laser etching. The number of each of the three channels can be one or more. The number of P1, P2, and P3 corresponds to the number of sub-solar cells. Non-limitingly, the first channel region P1, the second channel region P2, and the third channel region P3 can be configured as follows: the first channel region P1 is used to divide the first electrode 120 and must at least penetrate the first electrode 120; the second channel region P2 is used to penetrate and divide the first electron transport layer 150, the perovskite layer 140, and the first hole transport layer 130, and the two ends of the second channel region P2 are respectively connected to the second electrode 160 and the first electrode 120; the third channel region P3 is used to 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 first electron transport layer 150, the perovskite layer 140, and the first hole 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.

[0275] In some embodiments of this application, Figure 4-5 The substrate 110 in the structure shown is the light-incident side substrate.

[0276] 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.

[0277] 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.

[0278] 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.

[0279] 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.

[0280] 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.

[0281] 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.

[0282] In some embodiments, P1 in the solar cell can extend from the surface of the first hole transport layer to the bottom of the first electrode, and the P1 filling material is consistent with the perovskite layer (e.g., Figure 5 (As shown). In other embodiments, P1 in the solar cell may extend from the surface of the first electrode to the bottom, and the filling material in P1 is consistent with the first hole transport layer.

[0283] In some embodiments of the second aspect of this application, a method for preparing a solar cell is provided, comprising the following steps: sequentially depositing a first material and a second material on a first electrode, and performing an annealing treatment to form a first hole transport layer; wherein the second material contains sodium.

[0284] A perovskite layer is formed on the first hole transport layer, and a second electrode is formed on the perovskite layer;

[0285] The first hole transport layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface faces the perovskite layer, and the second surface faces the first electrode; a first region with a thickness of 1nm to 3nm exists within a region extending 5nm from the first surface into the first hole transport layer along the thickness direction, and a second region with a thickness of 1nm to 3nm exists within a region extending 5nm from the second surface into the first hole transport layer along the thickness direction; the first region is located between the first surface and the second region;

[0286] The proportion of sodium in the first substance in the first region is greater than that in the second region.

[0287] By sequentially forming a first material and a second material containing sodium on the first electrode, and allowing the sodium to naturally migrate from high to low concentration during annealing, the distribution trend of sodium in the first hole transport layer can be adjusted. This results in the first region of the first hole transport layer having a higher proportion of sodium than the second region, thus forming the aforementioned first hole transport layer. Furthermore, introducing an appropriate amount of sodium into the first hole transport layer and achieving the aforementioned distribution trend can improve the conductivity of the first hole transport layer, facilitating carrier transport, reducing non-radiative recombination, and thereby improving the photoelectric conversion efficiency of the solar cell.

[0288] In some embodiments, the mass percentage of sodium in the second material is 1wt% to 15wt%, optionally 5wt% to 10wt%, such as 1wt%, 2wt%, 4wt%, 5wt%, 7wt%, 9wt%, 10wt%, 12wt%, 14wt%, 15wt%, etc. This allows adjustment of the distribution trend of sodium in the first hole transport layer, ensuring that the mass percentage of sodium in the first region of the first hole transport layer is greater than that in the second region, thus forming the aforementioned first hole transport layer.

[0289] In some embodiments, the ratio of the thickness of the deposited first material to the thickness of the deposited second material is (0.1~3):1, optionally (0.5~2):1, such as 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc. In some embodiments, the thickness of the deposited second material is 3nm~20nm, optionally 5nm~15nm, such as 3nm, 5nm, 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, etc. In some embodiments, the thickness of the deposited second material is 0.3nm~60nm, optionally 1.5nm~40nm, further optionally 3nm~20nm, such as 0.3nm, 1.5nm, 3nm, 5nm, 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 30nm, 40nm, 50nm, 60nm, etc. In some embodiments, this can adjust the distribution trend of sodium in the first hole transport layer, so that the proportion of sodium in the first region of the first hole transport layer is greater than the proportion of sodium in the second region, thereby forming the first hole transport layer.

[0290] In some embodiments, the annealing conditions include: an annealing temperature of 150℃~300℃, such as 150℃, 160℃, 180℃, 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, etc.; and an annealing time of 5min~20min, such as 5min, 6min, 8min, 10min, 12min, 14min, 16min, 18min, 20min, etc. These annealing conditions promote the migration of sodium elements in the first hole transport layer, causing it to form a targeted distribution trend, improving the conductivity of the first hole transport layer, facilitating carrier transport, reducing non-radiative recombination, and thus improving the photoelectric conversion efficiency of the solar cell.

[0291] Understandably, deposition methods include sputtering. The first and second materials, after deposition, can form a hole transport material. For example, the first and second materials can be nickel-oxide-containing targets, and the first hole transport layer is prepared by sputtering. The second material can be a sodium-doped nickel-oxide target. The selection of the hole transport material formed after the deposition of the first and second materials is as defined above, and the specific type may be the same as or different from the hole transport materials defined above.

[0292] In some embodiments, the method for fabricating a solar cell further includes the step of fabricating a first electrode on a glass substrate, specifically including:

[0293] A glass substrate layer is provided, wherein the glass substrate includes a stacked sodium-containing glass layer, a sodium-blocking layer and a buffer layer, the sodium-blocking layer is located between the sodium-containing glass layer and the buffer layer, and the buffer layer is close to the first electrode;

[0294] A first electrode is disposed on the surface of the sodium-blocking layer of the glass substrate, and a first channel region is etched on the first electrode; the first channel region penetrates the first electrode and extends into the glass substrate; the depth of the first channel region in the glass substrate is less than the thickness of the buffer layer.

[0295] Sodium in the sodium-containing glass layer can migrate to functional layers such as the perovskite layer. A sodium-blocking layer can be used to prevent this migration, reducing the amount of sodium that migrates and effectively controlling its amount. However, during the etching of the first channel region, the first electrode needs to be completely severed to separate different cell units, which easily damages the sodium-blocking layer. This allows a large amount of sodium from the sodium-containing glass layer to migrate to the perovskite layer and other functional layers through the damaged areas. A buffer layer can isolate the first electrode from the sodium-blocking layer, making the sodium-blocking layer less susceptible to damage and effectively preventing sodium migration, thus achieving effective control over the amount of sodium migration.

[0296] In some embodiments, the sodium-blocking layer and the buffer layer can be prepared by deposition, wherein the deposition method includes at least one of the following: sol-gel method, vapor deposition method, coating method, and atomic deposition method. This facilitates the preparation of a uniform and well-distributed sodium-blocking layer, thereby improving the sodium-blocking effect of the sodium-blocking layer.

[0297] In some embodiments, the vapor deposition method may be physical vapor deposition; the physical vapor deposition method may be at least one of evaporation and sputtering; the evaporation method may be at least one of vacuum evaporation, thermal evaporation, and electron beam evaporation; and the sputtering method may be at least one of magnetron sputtering and ion plating sputtering. The coating method may be at least one of roll coating, extrusion coating, blade coating, and gravure coating.

[0298] In some embodiments, the sodium-blocking layer includes a silicon dioxide sodium-blocking layer; the preparation of the silicon dioxide sodium-blocking layer includes the following process:

[0299] A silica sol solution is prepared using a silicon-containing precursor. This silica sol solution is then coated onto one side of a soda-lime glass surface, followed by drying, aging, and heat treatment to form a silica sodium-barrier layer. Further, the silicon-containing precursor includes tetraethyl orthosilicate. Drying methods include vacuum flash evaporation, oven drying, and natural drying. Vacuum flash evaporation conditions include: evacuating to a vacuum level of 100 Pa to 600 Pa (e.g., 100 Pa, 200 Pa, 300 Pa, 400 Pa, 500 Pa, 600 Pa) for 2 to 20 seconds (e.g., 2 to 20 seconds), and maintaining this vacuum for 20 to 60 seconds (e.g., 20 to 60 seconds). Aging conditions include drying at 80℃~120℃ (e.g., 80℃, 90℃, 100℃, 110℃, 120℃, etc.) for 1h~4h (e.g., 1h, 2h, 3h, 4h, etc.); heat treatment conditions include treating at 400℃~500℃ (e.g., 400℃, 420℃, 440℃, 460℃, 480℃, 500℃, etc.) for 0.5h~2h (e.g., 0.5h, 1h, 1.5h, 2h, etc.).

[0300] In some embodiments, the buffer layer is prepared by sputtering.

[0301] Specifically, taking an inverted solar cell as an example, its preparation method includes the following steps:

[0302] Step 1: Prepare the base layer;

[0303] Step 2: Prepare a conductive layer on the substrate to form the first electrode;

[0304] Step 3: Fabricate the first hole transport layer on the transparent conductive glass electrode;

[0305] Step 4: Prepare a perovskite layer on the first hole transport layer;

[0306] Step 5: Prepare the first electron transport layer on the perovskite layer;

[0307] Step 6: Fabricate a second electrode on the first electron transport layer.

[0308] Specifically, between steps 3 and 4, or between steps 4 and 5, a step of preparing a passivation layer may also be included.

[0309] 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.

[0310] In some embodiments of the third aspect of this application, a photovoltaic module is provided, comprising at least one of the solar cells described in the first aspect and the solar cells prepared by the preparation method described in the second aspect. The aforementioned photovoltaic module has improved photoelectric conversion efficiency and long-term stability.

[0311] In some embodiments of the fourth aspect of this application, an electrical device is provided, including at least one of the solar cells of the first aspect and the solar cells prepared by the preparation method of the second aspect.

[0312] The aforementioned electrical devices have improved photoelectric conversion efficiency and long-term stability.

[0313] In some embodiments of the fifth aspect of this application, a power generation device is provided, including at least one of the solar cells of the first aspect and the solar cells prepared by the preparation method of the second aspect.

[0314] The aforementioned power generation device has improved photoelectric conversion efficiency and long-term stability.

[0315] 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.

[0316] 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.

[0317] 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.

[0318] Another example of an electrical device could be a mobile phone, tablet, laptop, calculator, etc.

[0319] Another example of an electrical device could be a wearable device, such as a watch.

[0320] 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.

[0321] In the following embodiments, "room temperature" refers to 20°C-30°C, and further, it can be 25°C.

[0322] In the following examples, unless otherwise specified, FTO is fluorine-doped tin oxide, FAI is formamidinium iodide, Me-4PACz is 4-(3,6-dimethyl-9H-carbazole-9-yl)butylphosphonic acid, DMF is N,N-dimethylformamide, and NMP is N-methyl-2-pyrrolidone.

[0323] Example 1

[0324] The solar cell uses an inverted pin structure and is fabricated as follows:

[0325] 1) Fabrication of the glass substrate and the first electrode:

[0326] a) Preparation of glass substrate: A set of 3.2 mm thick, 30 cm × 30 cm soda-lime glass (sodium element mass fraction of 13.71 wt%) was immersed in deionized water and ultrasonically treated for 10 min. Then it was washed twice with acetone and isopropanol in sequence, and then dried in a forced-air drying oven.

[0327] b) Preparation of the sodium barrier layer: The silica sodium barrier layer was prepared using the sol-gel method.

[0328] b1. Preparation of precursor sol: At room temperature, tetraethyl orthosilicate and anhydrous ethanol were mixed at a molar ratio of 1:20, and then 0.05 mol / L dilute hydrochloric acid solution was slowly added to it (at a molar ratio of tetraethyl orthosilicate: dilute hydrochloric acid solution = 1:2). The mixture was vigorously stirred mechanically for 24 hours. After the solution became clear, a stable silica sol solution was formed.

[0329] b2. Film formation: The precursor sol was uniformly coated onto the soda-lime glass surface at a speed of 10 mm / s using a blade coating method to form a wet film of about 1 μm thickness. Vacuum flash evaporation was used to rapidly evacuate the film from atmospheric pressure to 500 Pa within 10 s and maintain the pressure for 40 s. The precursor liquid film was then aged in an oven at 100 ℃ for 2 h to form a preliminary gel network. The film was then heat-treated in an air atmosphere muffle furnace at 5 ℃ / min to 450 ℃ for 1 h. After cooling for 24 h, a silicon dioxide sodium barrier layer of about 30 nm was obtained.

[0330] c) Buffer layer preparation: A glass substrate layer is formed on the surface of the sodium barrier layer by using RPD (ion plating sputtering) of approximately 18 nm SnO2 as a buffer layer;

[0331] d) Preparation of the first electrode: When the glass substrate temperature is 500℃, a methanol aqueous solution containing SnCl4·5H2O (0.8mol / L) and a methanol aqueous solution containing NH4F (0.1mol / L) are mixed at a volume ratio of 2:1 and sprayed onto the surface of the buffer layer several times by spray pyrolysis to obtain FTO of about 374nm. Then, it is annealed at 500℃ for 1h and cooled.

[0332] The prepared FTO was etched with an infrared laser to form the first channel region, which was about 20 μm wide (the depth of the first channel region in the glass substrate was 3 nm). The entire glass was divided into 42 cell units, each 6 mm wide, with a series resistance greater than 10 MΩ between different cell units. The top and bottom 12 mm areas were used as the component welding area. The etched FTO glass surface was cleaned twice with acetone and isopropanol, immersed in deionized water and ultrasonically treated for 10 min, then dried in a forced-air drying oven and placed in a drying room (humidity below 2%) to obtain the first electrode with the glass substrate (denoted as FTO conductive glass).

[0333] 2) Fabrication of the first hole transport layer:

[0334] a) Preparation of the first hole transport layer: The cleaned FTO conductive glass is placed in a magnetron sputtering device, and a nickel oxide target (first material, with a deposition thickness of about 10 nm) is deposited first; then a sodium-containing nickel oxide target (second material, with a sodium content of 5 wt% and a deposition thickness of about 10 nm) is deposited, and annealed at 250°C for 10 min to finally form the first hole transport layer.

[0335] 3) Preparation of electron blocking layer: Me-4PACz solution (0.30 mg / mL, isopropanol solution) was coated on hole transport layer using a slit coater to form a wet film (thickness of 4 μm), then dried with a 0.4 MPa air knife and annealed at 50 °C for 5 min to form electron blocking layer (thickness of about 1 nm).

[0336] 4) Preparation of the perovskite layer:

[0337] a) Prepare 1 mol / L FA 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 3. Perovskite precursor solution: Weigh 0.881 g of lead bromide, 35.774 g of lead iodide, 1.039 g of CsI and 13.070 g of FAI, add 80 mL of a mixed solvent of DMF and NMP with a volume ratio of 8:1, stir at 300 rpm for 4 h, and filter through a 0.22 μm PTFE membrane to obtain the perovskite precursor solution;

[0338] d) The above perovskite precursor solution was slit-coated onto the passivation layer, and then transferred to a vacuum equipment for 80 s vacuuming at a vacuum degree of 10 Pa. After annealing at 150°C for 2.5 min in an oven, it was quickly transferred to 100°C for annealing for 8 min. The resulting perovskite dry film (perovskite layer) had a thickness of approximately 440 nm.

[0339] 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 ALD device to deposit SnO2 with a thickness of approximately 20 nm at 100 °C as an electron transport layer.

[0340] 6) Preparation of the interface layer (as a hole blocking layer): After the transport layer is deposited, Cu with a thickness of about 10 nm is deposited on the surface of the electron transport layer and then removed by vacuum breaking. P2 is laser etched, with a width of 150 μm and a depth of etched to the surface of the FTO layer. The interval between P2 and P1 is 40 μm.

[0341] 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, a Cu layer with a thickness of approximately 90 nm is deposited. After cooling, the vacuum is broken and laser etching of P3 is performed. P3 has a width of 15 μm and a depth reaching the surface of the FTO layer. The spacing between P3 and P2 is 20 μm (the positions of the etching lines are P1 / P2 / P3 in sequence). Then, infrared edge cleaning is performed on the module, i.e., 12 mm is etched on each side of the module. In this way, the solar cell is obtained.

[0342] Examples 2-9

[0343] Except for some differences in raw material composition and preparation process, the remaining operation steps are the same as in Example 1. The differences are shown in Table 1.

[0344] Example 10

[0345] Except for the absence of a sodium-blocking layer and the adjustment of the buffer layer to 48 nm, the remaining operating steps are the same as in Example 1.

[0346] Example 11

[0347] Except for using SnO2 as the sodium barrier layer (the preparation process is the same as the buffer layer in Example 1) and adjusting the sodium barrier layer to 48nm (at this time, the sodium barrier layer material is the same as the buffer layer material, which is shown as the buffer layer in Table 1), the other operation steps are the same as in Example 1.

[0348] Test case

[0349] 1. SEM morphology observation:

[0350] The morphology of the glass substrate and the first electrode in Example 1 was observed, such as... Figure 4 As shown, the average thickness of the first electrode is 374 nm, and the thickness of the sodium-blocking layer is approximately 48.38 nm.

[0351] 2. Relative concentration or molar percentage of each element or ion in the perovskite device:

[0352] The perovskite component was etched to 56 nm in the FTO bulk phase. Time-of-flight secondary ion mass spectrometry (TOF-SIMs) was used in both cross-sectional imaging and depth profiling modes, combined with scanning 3D imaging, to determine the fingerprint of characteristic secondary ions. 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 (such as X1 or nickel) was calculated. The molar percentage of the target element or ion relative to a specific element (such as X1 or nickel) in the test area is the relative concentration. Specifically, the perovskite layer thickness was 440 nm, the etching rate was 2 nm / s, and the etching time ranged from 480 s to 700 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 700 s to 780 s. Based on the time, the corresponding positions could be determined, thus obtaining the number of ions of each element in different preset regions and calculating the relative content or molar percentage.

[0353] The etching path and qualitative analysis results of the solar cell in Example 1 are as follows: Figure 7 As shown in the figure, the relationship between the first mole fraction of sodium in the first hole transport layer and the test time in Example 1 is as follows. Figure 8 As shown, the relationship between the second relative concentration of sodium and the test time in the perovskite layer of Example 1 is illustrated in the figure. Figure 9 As shown.

[0354] In Example 1, the first relative concentration of sodium in the first hole transport layer is 1.00%, the first relative concentration of sodium in the first region is 1.66%, and the first relative concentration of sodium in the second region is 0.67%. In other embodiments, the first relative concentration of sodium in the first hole transport layer is between 0.1% and 3%; the first relative concentration of sodium in the first region is between 0.5% and 5%; the first relative concentration of sodium in the second region is between 0.05% and 2%, and the first relative concentration of sodium in the first region is greater than that in the second region.

[0355] In Example 1, the second substance content of sodium in the third region (extending 10-20 nm from the third surface toward the interior of the perovskite layer) is 3.91%, and in the fourth region (extending 10-20 nm from the fourth surface toward the interior of the perovskite layer) it is 1.43%. The second substance content of sodium in the perovskite layer generally shows a decreasing trend in the Z2 direction. In other embodiments, the second substance content of sodium in the third region is between 3% and 5%, and the second substance content of sodium in the fourth region is between 0.5% and 2.5%, with the same trend as in Example 1, and will not be repeated.

[0356] The average molar volume concentration of sodium in the perovskite layer of Example 1 was 0.000055447 mmol / cm³. 3 In other embodiments, the average molar volume concentration of chlorine in the perovskite layer is 0.00001 mmol / cm³. 3 ~0.0001mmol / cm 3 between.

[0357] 3. Initial performance of the device (optoelectronic devices used in solar cells)

[0358] Under normal temperature and pressure (25℃, 1 atmosphere), a standard light source with AM1.5G was used to simulate sunlight, conforming to the national standard IEC61215. The light intensity was corrected using crystalline silicon solar cells to achieve the intensity of one solar cell. The current-voltage characteristic curve (i.e., current-voltage curve) of the solar cell under the illumination of the light source was measured using a four-channel digital source meter (Keithley 2440). The open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and photoelectric conversion efficiency (PCE) of the solar cell were obtained.

[0359] The photoelectric conversion efficiency (PCE) is calculated as follows:

[0360] PCE = Pout / Pin

[0361] = Voc×Jsc×[(Vmpp×Jmpp) / (Voc×Jsc)] / Pin

[0362] = Voc×Jsc×FF / Pin.

[0363] 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 .

[0364] 4. Device stability determination (aging test)

[0365] 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 was recorded). The ratio of the photoelectric conversion efficiency 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) × 100%, which is used to evaluate stability. The higher the initial normalized efficiency, the better the device stability.

[0366] The composition and performance of the solar cells in the embodiments are shown in Tables 1-2.

[0367] Table 1. Composition and performance of the solar cells in the examples

[0368]

[0369] Note: "The first substance percentage of sodium in the first region C1" refers to the first substance percentage of sodium in the first region of the first hole transport layer, specifically the region extending 2nm from the first surface toward the interior of the hole transport layer; "The first substance percentage of sodium in the second region C2" refers to the first substance percentage of sodium in the second region of the first hole transport layer, specifically the region extending 2nm from the second surface toward the interior of the hole transport layer.

[0370] Table 2. Composition and performance of the solar cells in the embodiments (continued)

[0371]

[0372] Note: "Region C3" refers to the first relative concentration of sodium in the third region, which is specifically a region extending 10-20 nm from the third surface toward the interior of the perovskite layer; "Region C4" refers to the first relative concentration of sodium in the fourth region, which is specifically a region extending 10-20 nm from the fourth surface toward the interior of the perovskite layer; "Perovskite layer" refers to the first relative concentration of sodium in the perovskite layer.

[0373] As can be seen from Tables 1-2, the average molar volume concentration of sodium in the hole transport layer of the solar cell in this embodiment is 0.0001 mmol / cm³. 3 ~0.002mmol / cm 3Furthermore, the proportion of sodium in the first region is greater than that in the second region, resulting in improved photoelectric conversion efficiency and longer operating life. A comparison of Examples 1 and 10-11 shows that the average molar volume concentration of sodium in the hole transport layer is 0.0001 mmol / cm³. 3 ~0.001mmol / cm 3 Furthermore, a first relative concentration of sodium in the perovskite layer of 0.5% to 5% is preferred.

[0374] It is understood that the solar cells described above are not limited to those prepared by the methods used in the embodiments. The above embodiments are merely illustrative examples, and those skilled in the art may also use other preparation methods to obtain the solar cells protected by the first aspect of this application. For example, the second material may not be used, but other process parameters may be adjusted (e.g., processing in a sodium chloride atmosphere, or adjusting the material composition, etc.) to obtain the solar cells protected by the first aspect of this application. This application does not limit the preparation method of the solar cells protected by the first aspect.

[0375] 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, It includes a first electrode, a first hole transport layer, a perovskite layer, and a second electrode. The first hole transport layer and the perovskite layer are stacked between the first electrode and the second electrode. The first hole transport layer is located between the first electrode and the perovskite layer. The first hole transport layer includes sodium. The first hole transport layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface faces the perovskite layer, and the second surface faces the first electrode; a first region with a thickness of 1nm to 3nm exists within a region extending 5nm from the first surface into the first hole transport layer along the thickness direction, and a second region with a thickness of 1nm to 3nm exists within a region extending 5nm from the second surface into the first hole transport layer along the thickness direction; the first region is located between the first surface and the second region; The first proportion of sodium in the preset region is defined as the ratio of the amount of sodium in the preset region to the total amount of sodium in the first hole transport layer; the first proportion of sodium in the first region is greater than the first proportion of sodium in the second region.

2. The solar cell as described in claim 1, characterized in that, The average molar volume concentration of sodium in the first hole transport layer is 0.0001 mmol / cm³. 3 ~0.002mmol / cm 3 The value can be set to 0.0001 mmol / cm. 3 ~0.001mmol / cm 3 .

3. The solar cell as described in claim 1 or 2, characterized in that, It meets one or more of the following characteristics: (1) The first substance of sodium in the first region has a first substance content of 10%~45%, which can be selected as 10%~25%; (2) The first substance of sodium in the second region is 4% to 25%, and can be selected as 4% to 11%.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The direction from the first surface to the second surface in the thickness direction of the first hole transport layer is denoted as the Z1 direction. The proportion of sodium in the first substance of the first hole transport layer generally decreases in the Z1 direction.

5. The solar cell according to any one of claims 1 to 4, characterized in that, The first hole transport layer includes nickel oxide; the molar percentage of sodium in a predetermined region of the first hole transport layer relative to nickel in the predetermined region is denoted as the first relative concentration of sodium in the predetermined region; the first relative concentration of sodium in the first region is greater than the first relative concentration of sodium in the second region; Optionally, the first relative concentration of sodium in the first hole transport layer is 0.1% to 3%; Optionally, the first relative concentration of sodium in the first region is 0.5% to 5%; Optionally, the first relative concentration of sodium in the second region is 0.05% to 2%.

6. The solar cell according to any one of claims 1 to 5, characterized in that, The perovskite layer comprises a first perovskite material and sodium element; the first perovskite material comprises an X1 element, wherein the X1 element is selected from halogens and pseudohalogens. The perovskite layer has a third surface and a fourth surface that are opposite to each other in the thickness direction. The third surface faces the first hole transport layer, and the fourth surface faces the second electrode. A third region with a thickness of 5nm to 10nm exists in a region extending 20nm from the third surface toward the interior of the perovskite layer, and a fourth region with a thickness of 5nm to 10nm exists in a region extending 20nm from the fourth surface toward the interior of the perovskite layer. The molar percentage of sodium in a preset region relative to the X1 element in the preset region in the perovskite layer is denoted as the second relative concentration of sodium in the preset region. The second relative concentration of sodium in the third region is greater than the second relative concentration of sodium in the fourth region; Optionally, the X1 element exists in ionic form.

7. The solar cell as claimed in claim 6, characterized in that, It meets one or more of the following characteristics: (1) The second relative concentration of sodium in the perovskite layer is 0.5% to 7%, and may be 0.5% to 5%; (2) The second relative concentration of sodium in the third region is 1.5% to 11%, and can be selected as 1.5% to 6%; (3) The second relative concentration of sodium in the fourth region is 0.3% to 3.5%, and can be selected as 0.3% to 2.5%.

8. The solar cell as claimed in claim 6 or 7, characterized in that, The proportion of sodium in a predetermined region of the perovskite layer relative to the total amount of sodium in the perovskite layer is denoted as the second proportion of sodium in the predetermined region. The direction from the third surface to the fourth surface in the thickness direction of the perovskite layer is denoted as the Z2 direction, and the second proportion of sodium in the perovskite layer generally decreases in the Z2 direction.

9. The solar cell as claimed in claim 8, characterized in that, It meets one or more of the following characteristics: (1) The second substance of sodium in the third region accounts for 3% to 5% of the total amount of sodium. (2) The second substance of sodium in the fourth region accounts for 0.5% to 2.5% of the total amount.

10. The solar cell according to any one of claims 6 to 9, characterized in that, The average molar volume concentration of sodium in the perovskite layer is 0.00001 mmol / cm³. 3 ~0.0001mmol / cm 3 .

11. The solar cell according to any one of claims 1 to 10, characterized in that, The sodium element exists in the form of sodium ions.

12. The solar cell according to any one of claims 1 to 11, characterized in that, The solar cell further includes a glass substrate layer; the glass substrate layer is disposed on the side of the first electrode away from the perovskite layer.

13. The solar cell according to claim 12, characterized in that, The glass substrate layer includes a sodium-containing glass layer and a sodium-blocking layer; the sodium-blocking layer is disposed between the sodium-containing glass layer and the first electrode; Optionally, the sodium-blocking layer comprises at least one of graphene, molybdenum sulfide, silicon dioxide, and metal oxides; Further optionally, the metal oxide includes at least one of titanium oxide, zirconium oxide, aluminum oxide, tin oxide, and molybdenum oxide; Further optionally, the sodium-blocking layer further includes a downconversion material; the downconversion material includes at least one of rare earth complexes and inorganic substances.

14. The solar cell as claimed in claim 13, characterized in that, The glass substrate layer further includes a buffer layer; the buffer layer is disposed on the side of the sodium-blocking layer facing the first electrode; Optionally, the buffer layer comprises at least one of semiconductor metal oxides; Further optionally, the semiconductor metal oxide includes at least one of tin oxide and indium oxide.

15. The solar cell as claimed in claim 14, characterized in that, It meets one or more of the following characteristics: (1) The thickness ratio of the buffer layer to the sodium-blocking layer is (0.3~3.5):1; (2) The thickness of the sodium barrier layer is 10 nm to 100 nm.

16. The solar cell according to any one of claims 14-15, characterized in that, The solar cell has a first channel region; the first channel region penetrates the first electrode and extends into the glass substrate layer; the depth of the first channel region in the glass substrate layer is less than the thickness of the buffer layer.

17. The solar cell according to any one of claims 1 to 16, characterized in that, The solar cell is a multi-junction solar cell, which includes a first cell unit, the first cell unit including a first hole transport layer and the perovskite layer.

18. The solar cell according to claim 17, 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.

19. The solar cell according to claim 17 or 18, 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.

20. The solar cell according to any one of claims 17 to 19, characterized in that, The multi-junction solar cell includes a first electrode, a first hole transport layer, a perovskite layer, an interconnect layer, a second light absorption layer, and a second electrode stacked together; wherein the carrier recombination layer or the tunneling layer is located between the perovskite layer and the second light absorption layer; the first electrode is located on the side of the first hole 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 interconnect layer.

21. The solar cell according to any one of claims 17 to 19, characterized in that, The multi-junction solar cell includes a first electrode, a first hole 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, 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 hole 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.

22. The solar cell according to any one of claims 1 to 21, characterized in that, The perovskite layer is contained in the inverse or formal structure of the solar cell.

23. A method for preparing a solar cell, characterized in that, Includes the following steps: A first material and a second material are sequentially deposited on the first electrode and then annealed to form a first hole transport layer; wherein the second material contains sodium. A perovskite layer is formed on the first hole transport layer, and a second electrode is formed on the perovskite layer; The first hole transport layer has a first surface and a second surface that are opposite to each other in the thickness direction; the first surface faces the perovskite layer, and the second surface faces the first electrode; a first region with a thickness of 1nm to 3nm exists within a region extending 5nm from the first surface into the first hole transport layer along the thickness direction, and a second region with a thickness of 1nm to 3nm exists within a region extending 5nm from the second surface into the first hole transport layer along the thickness direction; the first region is located between the first surface and the second region; The proportion of sodium in the first substance in the first region is greater than that in the second region.

24. The preparation method according to claim 23, characterized in that, It meets one or more of the following characteristics: (1) In the second material, the mass percentage of sodium is 1wt%~15wt%, and can be selected as 5wt%~10wt%; (2) The ratio of the thickness of the first deposited material to the thickness of the second deposited material is (0.1~3):1, which can be (0.5~2):1; (3) The thickness of the second material deposited is 3nm~20nm, and can be selected as 5nm~15nm; (4) The annealing conditions include: annealing temperature of 150℃~300℃ and annealing time of 5min-20min.

25. The preparation method according to claim 23 or 24, characterized in that, The preparation method further includes the step of preparing a first electrode on a glass substrate, specifically including: A glass substrate layer is provided, wherein the glass substrate includes a stacked sodium-containing glass layer, a sodium-blocking layer and a buffer layer, the sodium-blocking layer being located between the sodium-containing glass layer and the buffer layer, and the buffer layer being close to the first electrode; The first electrode is disposed on the surface of the sodium-blocking layer of the glass substrate, and a first channel region is etched on the first electrode. The first channel region penetrates the first electrode and extends into the glass substrate. The depth of the first channel region in the glass substrate is less than the thickness of the buffer layer.

26. A photovoltaic module, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 22 and the solar cells prepared by the preparation method according to any one of claims 23 to 25.

27. An electrical appliance, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 22 and the solar cells prepared by the preparation method according to any one of claims 23 to 25.

28. A power generation device, characterized in that, It includes at least one of the solar cells according to any one of claims 1 to 22 and the solar cells prepared by the preparation method according to any one of claims 23 to 25.

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