Laminated solar cell, photovoltaic assembly, photovoltaic system, electric apparatus, and power generation apparatus

Abstract

The present application relates to a laminated solar cell, a photovoltaic assembly, a photovoltaic system, an electric apparatus, and a power generation apparatus. The laminated solar cell comprises: a first electrode layer; a first light absorption layer, which is disposed on a side of the first electrode layer; a composite layer, which is disposed on the side of the first light absorption layer that faces away from the first electrode layer, wherein the composite layer comprises a main elemental metal and a doped elemental metal, and the main elemental metal comprises an element capable of generating two or more energy level defects within the bandgap of a semiconductor material; a second light absorption layer, wherein the second light absorption layer is disposed on the side of the composite layer that faces away from the first light absorption layer; and a second electrode layer, which is disposed on the side of the second light absorption layer that faces away from the composite layer. The laminated solar cell in the present application has high photoelectric conversion efficiency.

Description

Tandem solar cells, photovoltaic modules, photovoltaic systems, electrical devices and power generation devices

[0001] Cross-references

[0002] This application claims priority from Chinese Patent Application No. 2024102710545, filed on March 8, 2024, entitled “Tandemized Solar Cells, Photovoltaic Modules, Photovoltaic Systems, Electrical Devices and Power Generation Devices,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of solar cells, and in particular to a stacked solar cell, a photovoltaic module, a photovoltaic system, an electrical device, and a power generation device. Background Art

[0004] With the rapid development of new energy, solar cells have been widely used in military, aerospace, industrial, commercial, agricultural, and communications fields. Perovskite solar cells, a device that converts solar energy into electrical energy using the photoelectric conversion mechanism of perovskite crystal materials, are currently the third generation of solar cells. They offer numerous advantages, including high photoelectric conversion efficiency, simple manufacturing processes, and low production costs, and have been the subject of extensive research in recent years.

[0005] A tandem solar cell is a type of solar cell composed of a wide-bandgap light-absorbing layer and a narrow-bandgap light-absorbing layer connected by a recombination layer. The two sub-cells are connected in series. After light absorption, the wide-bandgap and narrow-bandgap light-absorbing layers generate photogenerated carriers, respectively. The negative electrode of the narrow-bandgap sub-cell and the positive electrode of the wide-bandgap sub-cell serve as the electrodes for connecting the tandem solar cell to the external circuit. The positive electrode of the narrow-bandgap sub-cell and the negative electrode of the wide-bandgap sub-cell are connected by the recombination layer. When illuminated, the holes in the wide-bandgap sub-cell and the electrons in the narrow-bandgap sub-cell flow into the external circuit, generating an external current. The electrons in the wide-bandgap sub-cell and the holes in the narrow-bandgap sub-cell recombine and annihilate in the recombination layer, completing the entire circuit and forming a closed-loop path.

[0006] However, conventional tandem solar cells often suffer from poor electrical performance, such as poor fill factor and open-circuit voltage. Alternatively, they may suffer from high parasitic absorption, leading to low short-circuit current, ultimately impacting the cell's photoelectric conversion efficiency. Therefore, further improvements to tandem solar cells are necessary. Summary of the Invention

[0007] The present application is made in view of the above-mentioned problems, and one of its objectives is to provide a tandem solar cell having a high photoelectric conversion efficiency.

[0008] In order to achieve the above-mentioned objectives, the first aspect of the present application provides a tandem solar cell, comprising:

[0009] a first electrode layer;

[0010] a first light absorbing layer, disposed on one side of the first electrode layer;

[0011] a composite layer disposed on a side of the first light absorbing layer away from the first electrode layer, the composite layer comprising a main metal element and a doping metal element, wherein the main metal element comprises an element capable of generating two or more energy level defects in the band gap of the semiconductor material;

[0012] a second light absorbing layer, the second light absorbing layer being disposed on a side of the composite layer away from the first light absorbing layer; and

[0013] The second electrode layer is arranged on a side of the second light absorbing layer away from the composite layer.

[0014] The above-mentioned stacked solar cell of the present application is achieved by arranging a composite layer formed by multiple metal elements between the first light absorption layer and the second light absorption layer, wherein the composite layer includes a main metal element and a doped metal element, and the main metal element includes an element that can produce two or more energy level defects in the forbidden band of the semiconductor material, which can make the composite layer have a higher hole-electron recombination rate, wherein the semiconductor material refers to the light-absorbing semiconductor material in the light-absorbing layer; the introduction of doped metal elements into the composite layer can produce more allowed energy levels in the band gap than a single metal element, so that the energy difference between adjacent energy levels becomes smaller, the carrier transition between energy levels is faster, thereby increasing the recombination rate of a single defect, and correspondingly the thickness of the composite layer can be reduced, thereby reducing the parasitic absorption of the battery, improving the fill factor, open circuit voltage and short circuit current of the stacked solar cell, and improving the photoelectric conversion efficiency of the battery.

[0015] In any embodiment, the main metal element includes an element that can generate three or more energy level defects in the band gap of the semiconductor material. This can enable the recombination layer to have a higher hole-electron recombination rate, further improving the fill factor and open circuit voltage of the battery.

[0016] In any embodiment, the main metal element includes one or more of Au, Pt, Sn, Ag, Cu, Al, or Mg. These metal elements can provide the composite layer with a high recombination rate. Using them as the main metal element in the composite layer can result in a battery with a high fill factor and open circuit voltage.

[0017] In any embodiment, the doping metal element comprises one or more of Hg, Fe, Ga, Ni, Co, Au, Sn, Ag, Cu, Al, Mg, or Pt, and the main metal element and the doping metal element in the composite layer are of different types. Using the above metal elements as the doping metal element and adding them to the composite layer can effectively increase the number of allowed energy levels in the composite layer's band gap, effectively reduce the energy difference between adjacent energy levels, increase the carrier transition rate between energy levels, and thus increase the defect recombination rate.

[0018] In any embodiment, the thickness of the composite layer is 0.5 nm to 1.2 nm. The present application increases the recombination rate of individual defects in the composite layer by introducing a single dopant metal element; while maintaining a low series resistance, the thickness of the composite layer can be set to be thinner, which is beneficial for reducing parasitic absorption of the composite layer.

[0019] In any embodiment, the thickness of the composite layer is 0.8 nm to 1.0 nm. Controlling the thickness of the composite layer within the above range can further improve the photoelectric conversion efficiency of the battery.

[0020] In any embodiment, the mass fraction of the doping metal element in the composite layer is greater than 0% and less than 50%, and can be optionally 1% to 40%.

[0021] In any embodiment, the primary metal element comprises Au, and the dopant metal element comprises Fe; the mass fraction of Fe, based on the total mass of the composite layer, is greater than 0% and less than 10%. This effectively increases the recombination rate of individual defects in the composite layer while further improving the fill factor of the tandem solar cell.

[0022] In any embodiment, the mass fraction of Fe is 2% to 5% based on the total mass of the composite layer, thereby further improving the fill factor of the tandem solar cell.

[0023] In any embodiment, the main metal element includes Au, and the dopant metal element includes Pt; the mass fraction of Pt is 10% to 20% based on the total mass of the composite layer. This can further increase the recombination rate of the composite layer, increase the number of energy level defects in the composite layer by approximately 60%, and increase the rate of carrier extraction by the defects.

[0024] In any embodiment, the mass fraction of Pt is 14% to 16% based on the total mass of the composite layer.

[0025] In any embodiment, the main metal element includes Au, and the dopant metal element includes Ni and Co. Based on the total mass of the composite layer, the mass fraction of Ni is 5% to 10%, and the mass fraction of Co is 10% to 30%. This effectively increases the number of allowed energy levels in the band gap and the recombination rate of individual defects in the composite layer, while also enhancing the stability of the composite layer.

[0026] In any embodiment, based on the total mass of the composite layer, the mass fraction of Ni is 7% to 9%, and the mass fraction of Co is 14% to 16%. In this way, while increasing the stability of the composite layer, the fill factor and open circuit voltage of the battery are further improved.

[0027] In any embodiment, the composite layer further includes a doped non-metallic element, and the mass fraction of the doped non-metallic element in the composite layer is less than the mass fraction of the main metal element.

[0028] In any embodiment, the doping non-metallic element includes one or more of C, O, N, S, B, F or P.

[0029] In any embodiment, the primary metal element comprises Ag, and the doped non-metallic element comprises C; the mass fraction of C is 1% to 20% based on the total mass of the composite layer. This can increase the stability of the composite layer, and by adjusting the doping content of the doped non-metallic element C in the composite layer, the conductivity of the composite layer can be adjusted.

[0030] In any embodiment, the mass fraction of C is 4% to 6% based on the total mass of the composite layer.

[0031] In any embodiment, the first light absorbing layer is a wide bandgap perovskite light absorbing layer, and the second light absorbing layer is a narrow bandgap perovskite light absorbing layer.

[0032] A second aspect of the present application provides a photovoltaic assembly comprising the stacked solar cell of the first aspect of the present application.

[0033] A third aspect of the present application provides a photovoltaic system, comprising the photovoltaic assembly of the second aspect of the present application.

[0034] A fourth aspect of the present application provides an electrical device, comprising the photovoltaic system of the third aspect of the present application.

[0035] A fifth aspect of the present application provides a power generation device, comprising the photovoltaic system of the third aspect of the present application.

[0036] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to better describe and illustrate the embodiments or examples of the applications disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered to limit the scope of the disclosed applications, the embodiments or examples currently described, and any of the best modes currently understood for these applications. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0038] FIG1 is a schematic structural diagram of a tandem solar cell according to an embodiment of the present application;

[0039] FIG2 is a schematic diagram of the energy bands of a composite layer without adding a single doping metal element;

[0040] FIG3 is a schematic diagram of energy bands of a composite layer in which Pt is added to Au as a main metal element as a doping metal element in accordance with an embodiment of the present application;

[0041] FIG4 is a schematic structural diagram of an electric device according to an embodiment of the present application.

[0042] Explanation of the accompanying drawings: 10. Tandem solar cell; 11. First sub-cell; 12. Composite layer; 13. Second sub-cell; 111. First electrode layer; 112. First light absorption layer; 113. First hole transport layer; 114. First electron transport layer; 131. Second light absorption layer; 132. Second electrode layer; 133. Second hole transport layer; 134. Second electron transport layer. DETAILED DESCRIPTION

[0043] Below, some embodiments of the laminated solar cell, photovoltaic module, photovoltaic system, and electrical device of the present application are described in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0044] The "ranges" disclosed herein are defined in terms of lower and upper limits, where a given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values ​​and can be combined arbitrarily, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise indicated, the numerical range "a to b" is a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for a combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, stating that a parameter is an integer selected from "2-10" is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0045] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0046] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0047] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0048] 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." Furthermore, 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).

[0049] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0050] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0051] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0052] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc. shall be based on the technical solution that can implement the present application.

[0053] Herein, the terms "preferred," "better," "more preferred," and "suitable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0054] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0055] In this application, the terms "first," "second," "third," "fourth," etc. in "the first aspect," "the second aspect," "the third aspect," "the fourth aspect," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor should they be understood as implicitly indicating the importance or quantity of the indicated technical features. Furthermore, "first," "second," "third," "fourth," etc. serve only as non-exhaustive enumeration and description, and should be understood not to constitute a closed-ended limitation on quantity.

[0056] In this application, the term "room temperature" generally refers to 4°C to 35°C, and may refer to 20°C ± 5°C. In some embodiments of this application, room temperature refers to 20°C to 30°C.

[0057] In this application, when referring to a data range, if the unit is only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 3h~5h or 3h~5h both mean that the units of the left endpoint "3" and the right endpoint "5" are both hours.

[0058] The weights of the relevant components mentioned in the embodiment description of this application not only refer to the content of each component, but also represent the proportional relationship of the weights between the components. Therefore, as long as the content of the relevant components in the embodiment description of this application is proportionally enlarged or reduced according to the proportion, it is within the scope disclosed in the embodiment description of this application.

[0059] Referring to FIG. 1 , in some embodiments, the first aspect of the present application provides a tandem solar cell 10, comprising a first electrode layer 111 and a first light absorbing layer 112 disposed on one side of the first electrode layer 111; a composite layer 12 disposed on a side of the first light absorbing layer 112 facing away from the first electrode layer 111, the composite layer 12 comprising a primary metal element and a dopant metal element, the primary metal element comprising an element capable of generating two or more energy level defects in the band gap of the semiconductor material; a second light absorbing layer 131 disposed on a side of the composite layer 12 facing away from the first light absorbing layer 112; and a second electrode layer 132 disposed on a side of the second light absorbing layer 131 facing away from the composite layer. The first electrode layer 111 and the first light absorbing layer 112 constitute a first sub-cell 11, and the second light absorbing layer 131 and the second electrode layer 132 constitute a second sub-cell 13.

[0060] In the present application, “the main metal element single substance includes the ability to generate two or more energy level defects in the band gap of the semiconductor material” means that it is able to generate two or more energy level defects in the band gap of the light-absorbing semiconductor material in the light-absorbing layer. Taking the perovskite-perovskite two-junction tandem cell as an example, “being able to generate two or more energy level defects in the band gap of the semiconductor material” means that the main metal element single substance in the composite layer is able to generate two or more energy level defects in the band gap of the perovskite material of at least one of the perovskite materials of the two perovskite sub-cells. Taking the perovskite-crystalline silicon two-junction tandem cell as an example, “being able to generate two or more energy level defects in the band gap of the semiconductor material” means that the main metal element single substance in the composite layer is able to generate two or more energy level defects in the band gap of at least one of the crystalline silicon light-absorbing material of the crystalline silicon sub-cell and the perovskite material of the perovskite sub-cell.

[0061] When the tandem solar cell 10 is illuminated, the holes in the first subcell 11 and the electrons in the second subcell 13 flow into the external circuit, generating an external current. The electrons in the first subcell 11 and the holes in the second subcell 13 recombine and annihilate in the recombination layer 12, causing the entire circuit to conduct, forming a closed loop. Alternatively, the electrons in the first subcell 11 and the holes in the second subcell 13 flow into the external circuit, generating an external current. The holes in the first subcell 11 and the electrons in the second subcell 13 recombine and annihilate in the recombination layer 12, causing the entire circuit to conduct, forming a closed loop. The recombination rate of electrons and holes in the recombination layer 12 is a key factor in determining the conduction of the tandem solar cell 10. A low recombination rate in the recombination layer 12 prevents electrons and holes from effectively recombinating, increasing the series resistance within the tandem solar cell 10 and reducing the cell's fill factor. Furthermore, the accumulation of electrons and holes on both sides of the recombination layer 12 generates an electric field in the recombination layer 12, reducing the open-circuit voltage of the tandem solar cell 10.

[0062] Traditional tandem solar cells 10 typically use TCO (transparent conductive oxide) or a single metal element (such as Au) as the recombination layer 12. Compared to TCO, Au has a higher electron-hole recombination rate. However, when using a single metal element as the recombination layer 12, because the number of energy level defects generated in the two semiconductor band gaps is fixed, the recombination rate of the recombination layer 12 is primarily determined by the defect density. To achieve a high recombination rate, the recombination layer 12 must have sufficient thickness. However, as the thickness of the recombination layer 12 increases, parasitic absorption also increases, resulting in a lower short-circuit current for the tandem solar cell 10.

[0063] To address this issue, the tandem solar cell 10 of the present application comprises a composite layer 12 formed by a mixture of multiple metal elements between a first sub-cell 11 and a second sub-cell 13. Composite layer 12 includes a mixture of a primary metal element and a dopant metal element. The primary metal element includes an element capable of generating two or more energy level defects within the forbidden bandgap of the semiconductor material, enabling composite layer 12 to have a high recombination rate. The introduction of the dopant metal element into composite layer 12 generates more allowed energy levels within the bandgap than a single metal element, reducing the energy difference between adjacent energy levels and accelerating carrier transitions between energy levels, thereby increasing the recombination rate of individual defects. The recombination rate of composite layer 12 depends primarily on the recombination rate of individual defects and the defect density per unit area of ​​composite layer 12. The increased recombination rate of individual defects in composite layer 12 after the introduction of the dopant metal element allows for a corresponding reduction in the thickness of composite layer 12, thereby reducing parasitic absorption within the cell and improving the fill factor and short-circuit current of the tandem solar cell 10. The present application improves the composite layer 12 to reduce the series resistance and parasitic absorption inside the stacked solar cell 10, so that the stacked solar cell 10 has a higher fill factor, open circuit voltage and short circuit current, and has a higher photoelectric conversion efficiency.

[0064] The energy band diagram of the composite layer 12 without the addition of a single dopant metal element is shown in Figure 2; the energy band diagram of the composite layer 12 in one embodiment of the present application, in which Pt is added as a single dopant metal element to the main metal element Au, is shown in Figure 3. As shown in Figure 2, the allowed energy levels generated in the energy band of the composite layer 12 without the addition of a single dopant metal element are fixed, and the energy gap between the allowed energy levels is large. Therefore, the recombination rate is low. To meet the required recombination rate of the composite layer 12, the thickness of the composite layer 12 needs to be increased. As shown in Figure 3, after the introduction of the single dopant metal element, the allowed energy levels generated in the band gap of the composite layer 12 increase, thereby increasing the energy level density of the allowed energy levels in the band gap and reducing the energy gap between energy levels. This increases the rate of carrier extraction by defects and the recombination rate at a single defect site. Therefore, the performance requirements of the composite layer 12 can be met with a thinner thickness. This reduces the parasitic absorption of the composite layer 12 while reducing the series resistance of the battery.

[0065] It should be noted that the doping metal element is a metal element of a different type from the main metal element in the composite layer 12. Generally, the mass fraction of the main metal element in the composite layer 12 is greater than the mass fraction of the doping metal element. It is understood that the semiconductor material can be a semiconductor hole transport layer material, a semiconductor electron transport layer material, or a semiconductor light absorption layer material.

[0066] In some embodiments, the main metal element includes an element that can produce more than three energy level defects in the band gap of the semiconductor material. It is understandable that "can produce more than three energy level defects in the band gap of the semiconductor material" means that it can produce more than three energy level defects in the band gap of the light-absorbing semiconductor material in the light-absorbing layer. Taking the perovskite-perovskite two-junction tandem cell as an example, "can produce more than three energy level defects in the band gap of the semiconductor material" means that the main metal element in the composite layer can produce more than three energy level defects in the band gap of the perovskite material of at least one perovskite sub-cell. Taking the perovskite-crystalline silicon two-junction tandem cell as an example, "can produce more than three energy level defects in the band gap of the semiconductor material" means that the main metal element in the composite layer can produce more than three energy level defects in the band gap of at least one of the crystalline silicon light-absorbing material of the crystalline silicon sub-cell and the perovskite material of the perovskite sub-cell.

[0067] In some embodiments, the primary metal element comprises one or more of Au, Pt, Sn, Ag, Cu, Al, or Mg. Using the aforementioned metal elements as the primary metal element in the composite layer 12 can generate three or more energy level defects in the band gap of the semiconductor material, thereby enabling the composite layer 12 to have a higher recombination rate.

[0068] In some embodiments, the doping metal element single substance includes one or more of Hg, Fe, Ga, Ni, Co, Au, Sn, Ag, Cu, Al, Mg or Pt, and the main metal element single substance and the doping metal element single substance in the composite layer are of different types. By introducing the above-mentioned doping metal element single substance into the composite layer 12, it is possible to effectively increase the number of allowed energy levels in the band gap, effectively reduce the energy difference between adjacent energy levels, increase the transition speed of carriers between energy levels, and thus increase the recombination rate of defects. It is understandable that in the case where the doping metal element single substance includes one or more of Au, Sn, Ag, Cu, Al, Mg or Pt, the main metal element single substance and the doping metal element single substance are of different types. In this way, by doping the main metal element single substance with different doping metal elements, the number of allowed energy levels in the band gap is effectively increased, the energy difference between adjacent energy levels is effectively reduced, the transition speed of carriers between energy levels is increased, and thus the recombination rate of defects is increased.

[0069] In some embodiments, the thickness of the composite layer 12 is 0.5 nm to 1.2 nm; optionally, 0.8 nm to 1.0 nm. This application utilizes a mixture of a primary metal element and a dopant metal element in the composite layer 12, thereby increasing the recombination rate of individual defects in the composite layer 12 through the introduction of the dopant metal element. While maintaining a low series resistance, the thickness of the composite layer 12 of the tandem solar cell 10 can be set thinner, down to 0.5 nm. This effectively reduces parasitic absorption of the composite layer 12, resulting in the tandem solar cell 10 having a higher fill factor, open-circuit voltage, and short-circuit current, and a higher photoelectric conversion efficiency.

[0070] It can be understood that the thickness of the composite layer 12 can be 0.5nm, 0.55nm, 0.6nm, 0.65nm, 0.7nm, 0.75nm, 0.8nm, 0.85nm, 0.9nm, 0.95nm, 1.0nm, 1.05nm, 1.1nm, 1.15nm, 1.2nm and any value within the range formed by any two of the above values.

[0071] In some embodiments, the mass fraction of the doping metal element in the composite layer 12 is greater than 0% and less than 50%. In some specific examples, the mass fraction of the doping metal element in the composite layer 12 is greater than 0% and less than or equal to 40%. In other specific examples, the mass fraction of the doping metal element in the composite layer 12 is greater than or equal to 1% and less than or equal to 40%. The content of the doping metal element within the above range can effectively increase the number of allowed energy levels in the band gap and improve the recombination rate of individual defects in the composite layer 12.

[0072] It is understood that the mass fraction of the metal element doped in the composite layer 12 can be 0.5%, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 49%, 50%, or any value within the range formed by any two of the above values. The mass fraction of the metal element doped in the composite layer 12 can be reasonably set within the above mass fraction range according to the specific type of the metal element doped.

[0073] In one specific example, the primary metal element in the composite layer 12 is Au, and the dopant metal element is Fe. Furthermore, based on the total mass of the composite layer 12, the mass fraction of Fe in the composite layer 12 is greater than 0% and less than 10%. Using Au as the primary metal element in the composite layer 12 enables the composite layer 12 to have a high electron-hole recombination rate. Introducing Fe as the dopant metal element in the composite layer 12 at a mass fraction greater than 0% and less than 10% effectively increases the number of allowed energy levels in the band gap, improves the recombination rate of individual defects in the composite layer 12, and also enhances the stability of the tandem solar cell 10. In a composite layer 12 where the primary metal element is Au and the dopant metal element is Fe, the thickness of the composite layer 12 can range from 0.8 nm to 1.2 nm, and can further be 1 nm.

[0074] It can be understood that the mass fraction of Fe in the above-mentioned composite layer 12 can be 0.1%, 0.5%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5%, 9.8% and any value within the range formed by any two of the above values.

[0075] Furthermore, the mass fraction of Fe is 2% to 5% based on the total mass of the composite layer 12. When the mass fraction of the metallic element Fe in the composite layer 12 is within the above range, the fill factor of the tandem solar cell 10 can be further improved.

[0076] In some embodiments, the primary metal element in the composite layer 12 is Au, and the doping metal element is Pt; furthermore, the mass fraction of Pt is 10% to 20% based on the total mass of the composite layer 12. Introducing 10% to 20% Pt as the doping metal element in the composite layer 12 can further increase the recombination rate of the composite layer 12, increase the number of energy level defects in the composite layer 12 by approximately 60%, and significantly increase the number of energy level defects in the band gap. Accordingly, the energy gradient required to change during carrier recombination is reduced, thereby increasing the rate at which carriers are extracted by the defects. The thickness of the composite layer 12 can be reduced to approximately 0.5 nm, which meets the recombination rate requirements of the tandem solar cell 10 and effectively reduces parasitic absorption in the composite layer 12.

[0077] It is understood that the mass fraction of Pt in the composite layer 12 can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value within the range formed by any two of the above values. Furthermore, optionally, the mass fraction of Pt in the composite layer 12 is 14% to 16%. In some specific examples, the mass fraction of Pt in the composite layer 12 is 14%, 15%, or 16%.

[0078] In some embodiments, the main metal element in the composite layer 12 is Au, and the doping metal elements are Ni and Co. Furthermore, based on the total mass of the composite layer 12, the mass fraction of Ni is 5% to 10%, and the mass fraction of Co is 10% to 30%. Introducing 5% to 10% by mass of Ni and 10% to 30% by mass of Co as doping metal elements into the composite layer 12 not only effectively increases the number of allowed energy levels in the band gap and improves the recombination rate of single defects in the composite layer 12, but also increases the stability of the composite layer 12 and reduces the diffusion of Au.

[0079] It can be understood that the mass fraction of Ni in the above-mentioned composite layer 12 can be 5%, 6%, 7%, 8%, 9%, 10% and any value within the range formed by any two of the above values. Further optionally, the mass fraction of Ni in the above-mentioned composite layer 12 is 7% to 9%; the mass fraction of Co can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% and any value within the range formed by any two of the above values. Further optionally, the mass fraction of Co in the above-mentioned composite layer 12 is 14% to 16%.

[0080] In one specific example, the mass fraction of Ni in the composite layer 12 is 8%, and the mass fraction of Co is 15%. In this case, the stability of the composite layer 12 can be increased while further improving the photoelectric conversion efficiency of the tandem solar cell 10.

[0081] In some embodiments, the composite layer 12 further includes a dopant non-metallic element, and the mass fraction of the dopant non-metallic element in the composite layer 12 is less than the mass fraction of the main metal element. By introducing the dopant non-metallic element into the composite layer 12, other properties of the composite layer 12, such as stability, can be further improved.

[0082] Specifically, the doping non-metallic element introduced into the composite layer 12 may be one or more of C, O, N, S, B, F or P.

[0083] In a specific example, the primary metal element in the composite layer 12 is Ag, and the doping non-metallic element is C. Furthermore, the mass fraction of the doping non-metallic element C is 1% to 20% based on the total mass of the composite layer 12. By introducing the aforementioned amount of C as the doping non-metallic element into the composite layer 12 containing Ag as the primary metal element, the stability of the composite layer 12 can be increased, and by adjusting the doping content of the doping non-metallic element C in the composite layer 12, the conductivity of the composite layer 12 can be adjusted.

[0084] It can be understood that the mass fraction of the non-metallic element C doped in the composite layer 12 can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value within the range formed by any two of the above values. Further, optionally, the mass fraction of the non-metallic element C doped in the composite layer 12 is 4% to 6%. In a specific example, based on the total mass of the composite layer 12, the mass fraction of the non-metallic element C doped is 5%.

[0085] Similarly, introducing O, N, S, B, F, or P as doping non-metallic elements into the composite layer 12 can also play a similar role in improving the stability of the composite layer 12. It should be noted that the above-mentioned doping non-metallic elements can be introduced into the composite layer 12 in the form of a single substance or a compound (such as an oxide).

[0086] In some embodiments, the first sub-cell 11 is a wide-bandgap perovskite solar cell, and the second sub-cell 13 is a narrow-bandgap perovskite solar cell. Specifically, the first light absorption layer 112 in the first sub-cell 11 is a wide-bandgap perovskite light absorption layer, comprising a perovskite material with a bandgap of 1.6 eV to 2.3 eV; and the second light absorption layer 132 in the second sub-cell 13 is a narrow-bandgap perovskite light absorption layer, comprising a perovskite material with a bandgap of 1.1 eV to 1.4 eV.

[0087] In some embodiments, the first sub-cell 11 further includes a first hole transport layer 113 and a first electron transport layer 114; the second sub-cell 13 further includes a second hole transport layer 133 and a second electron transport layer 134. The first hole transport layer 113 is disposed between the first electrode layer 111 and the first light absorbing layer 112, and the first electron transport layer 114 is disposed between the first light absorbing layer 112 and the recombination layer 12; the second hole transport layer 133 is disposed between the recombination layer 12 and the second light absorbing layer 131, and the second electron transport layer 134 is disposed between the second light absorbing layer 131 and the second electrode layer 132.

[0088] That is, the structure of the above-mentioned stacked solar cell 10 includes a first electrode layer 111, a first hole transport layer 113, a first light absorption layer 112, a first electron transport layer 114, a composite layer 12, a second hole transport layer 133, a second light absorption layer 131, a second electron transport layer 134 and a second electrode layer 132 stacked in sequence.

[0089] In some embodiments, the material of the first electrode layer 111 includes one or more of indium tin oxide, lanthanide metal-doped indium oxide, boron-doped zinc oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, aluminum-doped zinc oxide, and gallium zinc oxide.

[0090] In some embodiments, the materials of the first hole transport layer 113 and the second hole transport layer 133 independently include [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-phenylamino)carbazole-spirobifluorene, poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate), polythiophene, nickel oxide, molybdenum oxide, cuprous iodide, cuprous oxide and one or more of its derivatives; and / or including one or more of doped or passivated [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-anilino)carbazole-spirobifluorene, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), polythiophene, nickel oxide, molybdenum oxide, cuprous iodide, cuprous oxide, and phosphate carbazole materials.

[0091] In some embodiments, the materials of the first light absorbing layer 112 and the second light absorbing layer 131 each independently include a perovskite layer including a material having a chemical formula of ABX3 or A2CDX6; wherein A includes CH3(NH2)2 + 、CH(NH2)2 + 、CH3NH2 + 、Li + 、Na + , K + , Rb + 、Cs + One or more of; B includes Pb 2+ 、Be 2+ 、Sn 2+ Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、Zn2+ 、Ge 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ One or more of; X includes Cl - Br - , I - 、SCN - 、CNO - 、OCN - 、OSCN - SH - OH - 、CP - 、CN - 、SeCN - 、N3 - 、NO2 - One or more of; C includes Ag + ; D includes Bi 3+ 、Sb 3+ 、In 3+ One or more of .

[0092] In some embodiments, the materials of the first electron transport layer 114 and the second electron transport layer 134 independently include bathocuproine, [6,6]-phenyl C 61 Methyl butyrate (PC 61 BM), [6,6]-phenyl C 71 Methyl butyrate (PC 71 BM), one or more of fullerene C60, fullerene C70, tin dioxide and zinc oxide.

[0093] In some embodiments, the material of the second electrode layer 132 includes one or more of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, tungsten and alloys thereof, and may also include one or more of indium tin oxide, lanthanide metal-doped indium oxide, boron-doped zinc oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, aluminum-doped zinc oxide, and gallium zinc oxide.

[0094] A second aspect of the present application provides a photovoltaic assembly comprising the stacked solar cell 10 of the first aspect of the present application.

[0095] The above-mentioned photovoltaic module includes one or more stacked solar cells 10, which can be selected according to the specific application scenario; further, the above-mentioned photovoltaic module includes multiple stacked solar cells 10, and the multiple stacked solar cells 10 are connected in series or in parallel to form a battery cell.

[0096] In some embodiments, the photovoltaic module further includes a photovoltaic glass layer, a bonding layer, and a back sheet.

[0097] Adhesive layers are provided on both surfaces of the cell, a back plate is provided on the surface of one of the adhesive layers away from the cell, and a photovoltaic glass layer is provided on the surface of the other adhesive layer away from the cell.

[0098] The photovoltaic glass layer and the back sheet are used to protect the laminated solar cells 10, and have the functions of sealing, insulation and waterproofing; the adhesive layer plays the role of bonding the photovoltaic glass layer and the cell, and bonding the back sheet and the cell.

[0099] Optionally, the photovoltaic glass layer is made of tempered glass, the back panel is made of TPT (polyvinyl fluoride) or TPE (thermoplastic elastomer), and the adhesive layer is made of EVA (polyethylene-polyvinyl acetate copolymer).

[0100] In some of these embodiments, the photovoltaic glass layer can also be replaced by a transparent organic material, which includes one or more of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, polyvinylidene fluoride, tetraacetyl cellulose, brominated phenoxy, aromatic polyamides, polyimides, polystyrenes, polyarylates, polysulfones, polyolefins, etc.

[0101] Furthermore, the photovoltaic module further includes a junction box and an outer frame.

[0102] The junction box is used to protect the power generation system of the entire photovoltaic module. It is equivalent to a current transfer station. When a battery cell short-circuits, the junction box will automatically disconnect the short-circuited battery string.

[0103] The outer frame can support and protect the entire photovoltaic module. The frame can be made of aluminum alloy, which has excellent strength and corrosion resistance.

[0104] Furthermore, silicone is used to bond and seal the connection between the frame and other parts of the photovoltaic module. Photovoltaic modules can convert solar energy into electrical energy, which can be stored in batteries or used to drive loads.

[0105] In some embodiments, the photovoltaic component is a solar panel.

[0106] A third aspect of the present application provides a photovoltaic system, comprising the above-mentioned photovoltaic assembly.

[0107] The photovoltaic system utilizes the laminated solar cells 10 in the photovoltaic modules to directly convert solar radiation energy into electrical energy with high efficiency and good stability. Furthermore, the photovoltaic system is a photovoltaic power generation system.

[0108] Photovoltaic modules are the core part of photovoltaic power generation systems. The above photovoltaic system includes one or more photovoltaic modules, which can be selected according to the specific application scenario; further, when the above photovoltaic system includes multiple photovoltaic modules, the multiple photovoltaic modules form a photovoltaic array.

[0109] The above photovoltaic system can be an independent photovoltaic power generation system or a grid-connected photovoltaic power generation system.

[0110] An independent photovoltaic power generation system consists of a photovoltaic array, a battery pack, a charge controller, a power electronic converter (inverter), and a load. Its operating principle is that solar radiation energy is first converted into electrical energy by the photovoltaic array, then converted by the power electronic converter to power the load. Meanwhile, excess electrical energy is stored as chemical energy in an energy storage device after passing through the charge controller. In this way, when sunlight is insufficient, the energy stored in the battery can be converted into 220V, 50Hz AC electricity after passing through the power electronic inverter, filtering, and power frequency transformer to supply the AC load.

[0111] A grid-connected photovoltaic power generation system consists of a photovoltaic array, a high-frequency DC / DC boost circuit, a power electronic converter (inverter), and system monitoring. Its operating principle is that solar radiation energy is converted by the photovoltaic array, then converted to high-voltage DC through high-frequency DC conversion. This is then inverted by a power electronic inverter and output to the grid as a sinusoidal AC current with a frequency consistent with the grid voltage.

[0112] The above two photovoltaic power generation systems have their own characteristics and can be selected according to specific application scenarios.

[0113] Please refer to FIG. 4 . A fourth aspect of the present application provides an electrical device including the above-mentioned photovoltaic system.

[0114] In some embodiments, the power-consuming device is a common device that includes the tandem solar cell 10 of the present application, such as those used in the fields of communications, transportation, industry and agriculture, and lighting. Examples of the power-consuming device include satellites, communications equipment, traffic lights, lighthouses, wireless phone booths, monitoring equipment for oil drilling, power systems, camping lanterns, electric vehicles, electronic device chargers, and building curtain walls.

[0115] A fifth aspect of the present application provides a power generation device comprising the above-mentioned photovoltaic system.

[0116] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0117] 1. Tandem solar cells

[0118] Example 1:

[0119] 1) Preparation of the first electrode layer

[0120] Indium tin oxide (ITO) conductive glass is used as the first electrode layer. The ITO conductive glass comprises a glass substrate and an ITO film disposed on the surface of the glass substrate. The ITO conductive glass is cleaned with acetone, alcohol, and deionized water in sequence, and dried before use.

[0121] 2) Preparation of the first hole transport layer

[0122] [4-(3,6-Dimethoxy-9H-carbazol-9-yl)butyl]phosphoric acid (MeO-4PACz) was added to an ethanol solvent and stirred, and the ethanol solution of MeO-4PACz was spin-coated onto the first electrode layer; the spin-coating speed was 4000 rpm, and the spin-coating time was 30 s; then the layer was transferred to a hot stage and annealed at 100°C for 10 minutes to form a first hole transport layer with a thickness of 1 nm.

[0123] 3) Preparation of the first light absorbing layer

[0124] 3 mg of FAI, 59 mg of FABr, 46 mg of CsI, 25 mg of CsBr, 428 mg of PbI2 and 209 mg of PbBr2 were added to 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF and DMSO was 3:1), stirred at 600 rpm on a magnetic stirrer for 8 h, and filtered to obtain a perovskite precursor solution. 100 μL of the above-mentioned perovskite precursor solution was spin-coated onto the surface of the above-mentioned first hole transport layer facing away from the first electrode layer; during the spin-coating process, the coating was first spun at a spin-coating speed of 2000 rpm and an acceleration of 200 rpm / s for 10 seconds, and then spun at a spin-coating speed of 4000 rpm and an acceleration of 1000 rpm / s for 25 seconds; after the spin-coating was completed, 200 μL of chlorobenzene was added to the spun perovskite precursor solution; then the above-mentioned perovskite precursor solution was spin-coated again, with a spin-coating speed of 4000 rpm and a spin-coating time of 15 seconds; then the film was transferred to a hot stage and annealed at 100°C for 15 minutes to form a first light absorption layer with a thickness of 400 nm.

[0125] 4) Preparation of the first electron transport layer

[0126] A 20 nm thick SnO2 thin film was deposited on the first light absorbing layer using an atomic layer deposition (ALD) device as a first electron transport layer.

[0127] 5) Composite layer preparation

[0128] An Au metal layer was evaporated onto the first electron transport layer using an evaporation device. During the evaporation process, a Pt metal element was uniformly doped into the Au metal layer by evaporation, forming a composite layer composed of Au as the primary metal element and Pt as the doping metal element. The composite layer had a thickness of 0.5 nm and a mass fraction of 90% Au and 10% Pt.

[0129] 6) Preparation of the second hole transport layer

[0130] Poly(3,4-ethylenedioxythiophene):poly(styrene sulfone) (PEDOT:PSS) was spin-coated on the composite layer at a speed of 4000 rpm for 30 seconds. The composite layer was then transferred to a hot plate and annealed at 150°C for 10 minutes to form a second hole transport layer with a thickness of 20 nm.

[0131] 7) Preparation of the second light absorbing layer

[0132] 2 mg of CH(NH2)2I, 85 mg of CH3NH2I, 4 mg of PbI2, 335 mg of SnI2, and 0.5 mg of MeO-4PACz were added to 1 mL of a mixed solvent of DMF and DMSO, with a volume ratio of DMF to DMSO of 3:1; the mixture was stirred at 600 rpm on a magnetic stirrer for 2 h, filtered, and a perovskite precursor solution was obtained; 100 μL of the perovskite precursor solution was spin-coated onto the second hole transport layer; and the mixture was spin-coated. During the coating process, the coating was first performed at a spin coating speed of 1000 rpm and an acceleration of 200 rpm / s for 10 seconds, and then at a spin coating speed of 3000 and an acceleration of 1000 rpm / s for 20 seconds; then 350 μL of ethyl acetate was added to the spin-coated perovskite precursor solution; then the above perovskite precursor solution was spin-coated again, with a spin coating speed of 4000 rpm and a spin coating time of 20 seconds; then it was transferred to a hot stage and annealed at 100°C for 10 minutes to form a second light absorption layer with a thickness of 1 μm.

[0133] 8) Preparation of the second electron transport layer

[0134] A 10 nm thick bathocuproin (BCP) layer was evaporated on the second light absorbing layer to serve as a second electron transport layer.

[0135] 9) Preparation of the second electrode layer

[0136] A 100 nm thick layer of metal copper (Cu) was evaporated on the second electron transport layer to form a second electrode layer, thereby preparing a perovskite stacked solar cell device.

[0137] Example 2:

[0138] This embodiment is substantially the same as the embodiment 1, with the only difference being that the mass fraction of the doping metal element Pt in the composite layer is 15%; correspondingly, the mass fraction of the main metal element Au is 85%.

[0139] Example 3:

[0140] This embodiment is substantially the same as the embodiment 1, with the only difference being that the mass fraction of the doping metal element Pt in the composite layer is 20%; correspondingly, the mass fraction of the main metal element Au is 80%.

[0141] Example 4:

[0142] This embodiment is basically the same as embodiment 1, with the only difference being that the thickness of the composite layer is 0.8 nm.

[0143] Example 5:

[0144] This embodiment is basically the same as embodiment 1, with the only difference being that the thickness of the composite layer is 1.2 nm.

[0145] Example 6:

[0146] This embodiment is basically the same as embodiment 1, with the only differences being that the thickness of the composite layer is 0.8 nm; the mass fraction of the main metal element Au in the composite layer is 99%; and the doped metal element Fe is used instead of Pt, and the mass fraction of Fe is 1%.

[0147] Example 7:

[0148] This embodiment is basically the same as embodiment 6, with the only difference being that the mass fraction of the main metal element Au in the composite layer is 98%; and the mass fraction of the doped metal element Fe is 2%.

[0149] Example 8:

[0150] This embodiment is basically the same as embodiment 6, with the only difference being that the mass fraction of the main metal element Au in the composite layer is 95%; and the mass fraction of the doped metal element Fe is 5%.

[0151] Example 9:

[0152] This embodiment is basically the same as embodiment 6, with the only difference being that the mass fraction of the main metal element Au in the composite layer is 91%; and the mass fraction of the doped metal element Fe is 9%.

[0153] Example 10:

[0154] This embodiment is basically the same as embodiment 6, with the only difference being that the thickness of the composite layer is 1.0 nm.

[0155] Example 11:

[0156] This embodiment is basically the same as embodiment 6, with the only difference being that the thickness of the composite layer is 1.2 nm.

[0157] Example 12:

[0158] This embodiment is basically the same as embodiment 1, with the only difference being that the thickness of the composite layer is 0.8 nm; the mass fraction of the main metal element Au in the composite layer is 85%; and Ni and Co are used instead of Pt as doped metal elements, with the mass fraction of Ni being 5% and the mass fraction of Co being 10%.

[0159] Example 13:

[0160] This embodiment is basically the same as embodiment 12, with the only difference being that the mass fraction of the main metal element Au in the composite layer is 77%; the mass fraction of the doped metal element Ni is 8%, and the mass fraction of Co is 15%.

[0161] Example 14:

[0162] This embodiment is basically the same as embodiment 12, with the only difference being that the mass fraction of the main metal element Au in the composite layer is 60%; the mass fraction of the doped metal element Ni is 10%; and the mass fraction of Co is 30%.

[0163] Example 15:

[0164] This embodiment is basically the same as Example 1, with the only difference being that Ag is used instead of Au as the main metal element in the composite layer, and C is introduced as a doping non-metallic element during the evaporation process; wherein the mass fraction of Ag is 89%; the mass fraction of the doping metal element Pt is 10%; and the mass fraction of the doping non-metallic element C is 1%.

[0165] Example 16:

[0166] This embodiment is basically the same as embodiment 15, with the only difference being that the mass fraction of the main metal element Ag in the composite layer is 85%; the mass fraction of the doped metal element Pt is 10%; and the mass fraction of the doped non-metallic element C is 5%.

[0167] Example 17:

[0168] This embodiment is basically the same as embodiment 15, with the only difference being that the mass fraction of the main metal element Ag in the composite layer is 80%; the mass fraction of the doped metal element Pt is 10%; and the mass fraction of the doped non-metallic element C is 10%.

[0169] Example 18:

[0170] This embodiment is basically the same as embodiment 15, with the only difference being that the mass fraction of the main metal element Ag in the composite layer is 70%; the mass fraction of the doped metal element Pt is 10%; and the mass fraction of the doped non-metallic element C is 20%.

[0171] Example 19:

[0172] This embodiment is basically the same as embodiment 15, with the only difference being that the mass fraction of the main metal element Ag in the composite layer is 89%; the mass fraction of the doped metal element Pt is 10%; and the mass fraction of the doped non-metallic element S is 1%.

[0173] Example 20:

[0174] This embodiment is basically the same as embodiment 15, with the only difference being that the mass fraction of the main metal element Ag in the composite layer is 89%; the mass fraction of the doped metal element Pt is 10%; and the mass fraction of the doped non-metallic element B is 1%.

[0175] Comparative Example 1:

[0176] This comparative example is basically the same as Example 11, with the only difference being that the metal element Au is used as the composite layer, and the doped metal element Fe is not introduced into the composite layer.

[0177] Comparative Example 2:

[0178] This comparative example is basically the same as Example 1, except that: a metal element single substance Au is used as the composite layer, a doped metal element single substance Pt is not introduced into the composite layer, and the thickness of the composite layer is 2 nm.

[0179] 2. Performance Testing

[0180] 1) Energy level defect testing method

[0181] The deep energy level transient spectroscopy method is used for detection. That is, a heavily doped pn diode sample structure that can still maintain good diode characteristics at high temperatures is used. By measuring the high-temperature energy level transient capacitance spectrum at different filling voltages, the signals of majority-carrier traps and minority-carrier traps in the sample are simultaneously obtained. Finally, the Arrhenius curve is used to obtain the energy level position and concentration information of the energy level defect states in the sample.

[0182] 2) Determination of element content in composite layer

[0183] The element content in the composite layer can be tested by XPS (photoelectron spectroscopy) or EDX (X-ray spectrometry).

[0184] 3) Stability test method for tandem solar cells

[0185] The tandem solar cell was placed at 65°C and 100 mW / cm 2 The researchers continuously exposed the tandem solar cell to a light source of 100 nm and tracked its photoelectric conversion efficiency over time. The time it takes for the photoelectric conversion efficiency to decay to 80% of its initial efficiency was recorded as T80. This parameter indicates the stability of the tandem solar cell. A smaller T80 value indicates worse stability; a larger T80 value indicates better stability.

[0186] 4) Test methods for battery fill factor, open circuit voltage, short circuit current and photoelectric conversion efficiency

[0187] Under standard simulated sunlight (AM1.5G, 100mW / cm 2 ) irradiation, the battery performance is tested and the IV curve is obtained. According to the IV curve and the data fed back by the test equipment, the short-circuit current Jsc (unit: mA / cm 2 ), open circuit voltage Voc (unit V), maximum light output current Jmpp (unit mA) and maximum light output voltage Vmpp (unit V).

[0188] The fill factor FF of the battery is calculated by the formula FF = (Vmpp × Jmpp) / (Voc × Jsc), in units of %.

[0189] The photoelectric conversion efficiency (PCE) of the battery is calculated using the formula PCE=Jsc×Voc×FF / Pin, in %. Pin represents the input power of the incident light, in mW.

[0190] The parameters and performance test results of the perovskite tandem solar cells of various embodiments and comparative examples are shown in Table 1.

[0191] Table 1

[0192] Table 2

[0193] As shown in Table 2, the tandem solar cell of the present application has a high fill factor, open circuit voltage, and short circuit current, and has a high photoelectric conversion efficiency. Compared with Example 11, Comparative Example 1 does not introduce a single doping metal element into the composite layer. Although the short circuit current of the battery is comparable to that of Example 11, the fill factor and open circuit voltage are reduced, and the photoelectric conversion efficiency is reduced. Comparative Example 2 does not introduce a single doping metal element into the composite layer, and the thickness of the composite layer is increased. Although the fill factor and open circuit voltage of the battery are relatively high, the parasitic absorption increases due to the increase in the thickness of the composite layer, and the short circuit current of the battery decreases significantly, and the photoelectric conversion efficiency decreases.

[0194] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0195] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A tandem solar cell comprising: a first electrode layer; a first light absorbing layer, disposed on one side of the first electrode layer; a composite layer disposed on a side of the first light absorbing layer away from the first electrode layer, the composite layer comprising a main metal element and a doping metal element, wherein the main metal element comprises an element capable of generating two or more energy level defects in the band gap of the semiconductor material; a second light absorbing layer, the second light absorbing layer being disposed on a side of the composite layer away from the first light absorbing layer; and The second electrode layer is arranged on a side of the second light absorbing layer away from the composite layer.

2. The tandem solar cell according to claim 1, wherein: The main metal element single substance includes an element that can generate three or more energy level defects in the band gap of the semiconductor material.

3. The tandem solar cell according to claim 1 or 2, wherein: The main metal element single substance includes one or more of Au, Pt, Sn, Ag, Cu, Al or Mg.

4. The tandem solar cell according to any one of claims 1 to 3, wherein The doped metal element single substance includes one or more of Hg, Fe, Ga, Ni, Co, Au, Sn, Ag, Cu, Al, Mg or Pt, and the main metal element single substance and the doped metal element single substance in the composite layer are of different types.

5. The tandem solar cell according to any one of claims 1 to 4, wherein The thickness of the composite layer is 0.5 nm to 1.2 nm.

6. The tandem solar cell according to claim 5, wherein: The thickness of the composite layer is 0.8 nm to 1.0 nm.

7. The tandem solar cell according to any one of claims 1 to 6, wherein The mass fraction of the doped metal element in the composite layer is greater than 0% and less than 50%.

8. The tandem solar cell according to claim 7, wherein: The mass fraction of the doped metal element in the composite layer is 1% to 40%.

9. The tandem solar cell according to any one of claims 1 to 8, wherein The main metal element single substance includes Au, and the doping metal element single substance includes Fe; based on the total mass of the composite layer, the mass fraction of Fe is greater than 0% and less than 10%.

10. The tandem solar cell according to claim 9, wherein: Based on the total mass of the composite layer, the mass fraction of Fe is 2% to 5%.

11. The tandem solar cell according to any one of claims 1 to 10, wherein The main metal element single substance includes Au, and the doping metal element single substance includes Pt; based on the total mass of the composite layer, the mass fraction of Pt is 10% to 20%.

12. The tandem solar cell according to claim 11, wherein: Based on the total mass of the composite layer, the mass fraction of Pt is 14% to 16%.

13. The tandem solar cell according to any one of claims 1 to 12, wherein: The main metal element single substance includes Au, and the doping metal element single substance includes Ni and Co; based on the total mass of the composite layer, the mass fraction of Ni is 5% to 10%, and the mass fraction of Co is 10% to 30%.

14. The tandem solar cell according to claim 13, wherein: Based on the total mass of the composite layer, the mass fraction of Ni is 7% to 9%, and the mass fraction of Co is 14% to 16%.

15. The tandem solar cell according to any one of claims 1 to 14, wherein The composite layer further includes a doped non-metallic element, and the mass fraction of the doped non-metallic element in the composite layer is less than the mass fraction of the main metal element.

16. The tandem solar cell according to claim 15, wherein: The doping non-metallic elements include one or more of C, O, N, S, B, F or P.

17. The tandem solar cell according to claim 15, wherein: The main metal element includes Ag, and the doped non-metallic element includes C; based on the total mass of the composite layer, the mass fraction of C is 1% to 20%.

18. The tandem solar cell according to claim 17, wherein: Based on the total mass of the composite layer, the mass fraction of C is 4% to 6%.

19. The tandem solar cell according to any one of claims 1 to 18, wherein The first light absorbing layer is a wide bandgap perovskite light absorbing layer, and the second light absorbing layer is a narrow bandgap perovskite light absorbing layer.

20. A photovoltaic module comprising the tandem solar cell according to any one of claims 1 to 19.

21. A photovoltaic system comprising the photovoltaic module according to claim 20.

22. An electrical device comprising the photovoltaic system according to claim 21.

23. A power generation device comprising the photovoltaic system according to claim 21.

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