Stacked batteries and their manufacturing methods

Abstract

This disclosure relates to the photovoltaic field, providing a tandem solar cell and a method for manufacturing the same. The tandem solar cell includes: a crystalline silicon base cell, comprising a substrate and a doped conductive layer on the surface of the substrate; a composite layer, located on the surface of the crystalline silicon base cell, the composite layer being made of a metal oxide, wherein the portion of the doped conductive layer near the composite layer is doped with the same metal element as the metal element in the composite layer; and a perovskite top cell, located on the surface of the composite layer away from the crystalline silicon base cell, which can improve the photoelectric conversion efficiency of the tandem solar cell.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a tandem solar cell and its manufacturing method. Background Technology

[0002] Currently, with the gradual depletion of fossil fuels, solar cells are becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts sunlight into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient utilization of electrical energy.

[0003] Current solar cells mainly include monolayer cells, such as IBC cells (Interdigitated Back Contact), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated emitter and real cell), HIT / HJT cells (Heterojunction Technology), and perovskite cells. Different film layer configurations and functional limitations are used to reduce optical losses and decrease photogenerated carrier recombination on and within the silicon substrate, thereby improving the photoelectric conversion efficiency of solar cells.

[0004] Research has revealed that perovskite solar cells possess a semi-transparent characteristic, meaning photons can pass through them. This allows us to add photovoltaic cells underneath perovskite cells, thus breaking the efficiency limit of single-junction solar cells through "stacking," a process known as tandem solar cells. The principle of tandem solar cells is that the wide-bandgap top cell absorbs high-energy photons, while the narrow-bandgap bottom cell improves photon utilization. Together, they can break through the theoretical efficiency limit of single-junction cells, unlocking the ceiling of conversion efficiency. However, further improvements in the photoelectric conversion efficiency of tandem solar cells are still necessary. Summary of the Invention

[0005] This disclosure provides a stacked battery and a method for manufacturing the same, which can at least improve the photoelectric conversion efficiency of the stacked battery.

[0006] According to some embodiments of this disclosure, one aspect of this disclosure provides a tandem solar cell, comprising: a crystalline silicon bottom cell, the crystalline silicon bottom cell including a substrate and a doped conductive layer located on the surface of the substrate; a composite layer located on the surface of the crystalline silicon bottom cell, the composite layer being made of a metal oxide, wherein the portion of the doped conductive layer near the composite layer is doped with a metal element identical to the metal element in the composite layer; and a perovskite top cell located on the surface of the composite layer away from the crystalline silicon bottom cell.

[0007] In some embodiments, the thickness of the metal element doped in the doped conductive layer is 10 nm to 20 nm.

[0008] In some embodiments, in the direction from the composite layer to the doped conductive layer, the concentration of metal elements in the doped conductive layer gradually decreases.

[0009] In some embodiments, the composite layer is made of indium tin oxide.

[0010] In some embodiments, the ratio of the doping concentration of tin ions to the doping concentration of indium ions in the doped conductive layer is 7 to 13.

[0011] In some embodiments, the ratio of tin doping concentration to indium doping concentration in the composite layer is 4 to 19.

[0012] According to some embodiments of this disclosure, another aspect of this disclosure provides a method for fabricating a tandem solar cell, comprising: providing a crystalline silicon bottom solar cell, the crystalline silicon bottom solar cell including a substrate and a doped conductive layer located on the surface of the substrate; forming a composite layer located on the surface of the crystalline silicon bottom solar cell, the composite layer being made of a metal oxide, wherein, during the formation of the composite layer, the metal elements of the composite layer are controlled to diffuse into the doped conductive layer; and forming a perovskite top solar cell located on the surface of the composite layer away from the crystalline silicon bottom solar cell.

[0013] In some embodiments, the method of forming the composite layer includes: constructing a magnetic field environment, wherein the crystalline silicon base cell is located within the magnetic field environment; performing a magnetron sputtering process, wherein the magnetron sputtering process includes: providing a target material, bombarding the target material with plasma, and providing an oxidizing gas to bombard the metal elements contained in the target material onto the surface of the doped conductive layer to form the composite layer; and controlling the metal elements to be doped into the doped conductive layer during the formation of the composite layer.

[0014] In some embodiments, the magnetic field strength of the magnetic field environment is 0.5T~1.5T, and the process parameters of the magnetron sputtering include: sputtering power of 0.5KW~1KW and temperature environment of 350℃~450℃.

[0015] In some embodiments, the process of forming the composite layer further includes: detecting the thickness of the composite layer; when the thickness of the formed composite layer is less than 5 nm, the magnetic field strength is a first preset magnetic field strength; when the thickness of the formed composite layer is 5 nm to 20 nm, the magnetic field strength is a second preset magnetic field strength; when the thickness of the formed composite layer is greater than 20 nm, the magnetic field strength is a third preset magnetic field strength, wherein the first preset magnetic field strength is less than the second preset magnetic field strength and less than the third preset magnetic field strength.

[0016] In some embodiments, the method of forming the composite layer includes: providing a laser that irradiates the surface of the doped conductive layer; performing a magnetron sputtering process, the magnetron sputtering process including: providing a target material, bombarding the target material with plasma, and providing an oxidizing gas to bombard the metal elements contained in the target material onto the surface of the doped conductive layer irradiated by the laser to form the composite layer; and controlling the metal elements to be doped into the doped conductive layer during the formation of the composite layer.

[0017] The technical solution provided by the embodiments of this disclosure has at least the following advantages: On the one hand, by setting the portion of the doped conductive layer near the composite layer to be doped with the same metal element as the metal element in the composite layer, the interface difference between the doped conductive layer and the composite layer can be reduced, and the reliability of the contact between the doped conductive layer and the composite layer can be improved. At the same time, the portion of the doped conductive layer near the composite layer to be doped with the same metal element as the metal element in the composite layer reduces the interface porosity of the doped conductive layer, realizes passivation of part of the doped conductive layer, and thus improves the photoelectric conversion efficiency of the tandem solar cell. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a stacked battery structure provided in one embodiment of the present disclosure;

[0020] Figure 2 A flowchart illustrating a method for manufacturing a stacked battery according to an embodiment of this disclosure;

[0021] Figure 3 This is a schematic diagram of the structure of a crystalline silicon bottom cell provided in an embodiment of the present disclosure;

[0022] Figure 4 This is a schematic diagram of the structure of a composite layer formed on a crystalline silicon bottom cell and a perovskite top cell provided in an embodiment of this disclosure.

[0023] Explanation of reference numerals in the attached figures:

[0024] 100. Crystalline silicon bottom cell; 110. Substrate; 120. Doped conductive layer; 101. Composite layer; 102. Perovskite top cell; 130. Tunneling layer; 140. Emitter; 150. First passivation layer; 160. First surface; 170. Second surface; 112. First transport layer; 122. Perovskite substrate; 132. Second passivation layer; 142. Second transport layer; 152. Third transport layer; 162. Transparent conductive layer; 103. Back electrode; 104. Front electrode. Detailed Implementation

[0025] As can be seen from the background technology, it is currently necessary to improve the photoelectric conversion efficiency of tandem solar cells.

[0026] This disclosure provides a tandem solar cell and its fabrication method. On one hand, the portion of the doped conductive layer near the composite layer is doped with the same metal element as the metal element in the composite layer. This reduces the interface difference between the doped conductive layer and the composite layer, improving the reliability of the contact between them. Simultaneously, the doping of the portion of the doped conductive layer near the composite layer with the same metal element reduces the interface porosity of the doped conductive layer, achieving passivation of the partially doped conductive layer, thereby improving the photoelectric conversion efficiency of the tandem solar cell.

[0027] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In the description of embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0031] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0032] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0033] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0034] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly" on the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0035] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0036] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0037] refer to Figure 1 , Figure 1 This is a schematic diagram of a stacked battery provided in an embodiment of the present disclosure.

[0038] In some embodiments, the stacked cell may include: a crystalline silicon base cell 100, the crystalline silicon base cell 100 including a substrate 110 and a doped conductive layer 120 located on the surface of the substrate 110.

[0039] The tandem solar cell may further include: a composite layer 101, which is located on the surface of the crystalline silicon bottom cell 100. The composite layer 101 is made of a metal oxide, wherein the portion of the doped conductive layer 120 near the composite layer 101 is doped with the same metal element as the metal element in the composite layer 101.

[0040] The tandem solar cell may further include a perovskite top cell 102, which is located on the surface of the composite layer 101 away from the crystalline silicon bottom cell 100.

[0041] In this embodiment, on the one hand, the portion of the doped conductive layer 120 near the composite layer 101 is doped with the same metal element as the metal element in the composite layer 101. This reduces the interface difference between the doped conductive layer 120 and the composite layer 101, improving the reliability of the contact between them. Simultaneously, the doping of the portion of the doped conductive layer 120 near the composite layer 101 with the same metal element reduces the interface porosity of the doped conductive layer 120, achieving passivation of the portion of the doped conductive layer 120, thereby improving the photoelectric conversion efficiency of the tandem solar cell.

[0042] The crystalline silicon bottom cell 100 includes any one of the following: PERC cell (Passivated Emitter and Rear Cell), PERT cell (Passivated Emitter and Rear Totally-diffused cell), TOPCon cell (Tunnel Oxide Passivated Contact), HIT / HJT cell (Heterojunction Technology), or BC cell (BackContact).

[0043] The following explanation will use the crystalline silicon base cell 100 as an example of a TOPCon battery. It should be noted that when the crystalline silicon base cell 100 is used for other types of batteries, the other structures of the crystalline silicon base cell 100 can be adjusted accordingly, which will not be elaborated here.

[0044] In some embodiments, the crystalline silicon bottom cell 100 includes: a substrate 110, the substrate 110 including opposing first surfaces 160 and second surfaces 170; a tunneling layer 130 located on the second surface 170; a doped conductive layer 120 located on the surface of the tunneling layer 130 away from the substrate 110; an emitter 140 located within the substrate 110 or on the first surface 160 of the substrate 110; and a first passivation layer 150 located on the surface of the emitter and away from the substrate 110.

[0045] The first surface 160 and the second surface 170 of the substrate 110 can both serve as light-receiving surfaces to receive incident light. The first surface 160 and / or the second surface 170 of the substrate 110 may also have a textured surface to increase light reflection and improve light utilization.

[0046] The tunneling layer 130 can passivate the substrate 110. Due to interface state defects at the interface between the substrate 110 and the tunneling layer 130, the interface state density on the back side of the substrate 110 is relatively high. This increased interface state density promotes the recombination of photogenerated carriers, reducing the fill factor, short-circuit current, and open-circuit voltage of the solar cell, thus decreasing its photoelectric conversion efficiency. By placing the tunneling layer 130 on the surface of the substrate 110, it chemically passivates the surface of the substrate 110. Specifically, by saturating the dangling bonds of the substrate 110, it reduces the defect state density of the substrate 110, decreases the recombination centers, and lowers the carrier recombination rate, thereby improving the fill factor, short-circuit current, and open-circuit voltage of the solar cell, and ultimately increasing its photoelectric conversion efficiency.

[0047] The material of the tunneling layer 130 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0048] The doped conductive layer 120 can also act as a field passivation layer, forming an electrostatic field on the surface of the substrate 110 pointing towards the interior of the substrate 110. This causes minority carriers to escape from the interface, thereby reducing the minority carrier concentration and decreasing the carrier recombination rate at the interface of the substrate 110. Consequently, the open-circuit voltage, short-circuit current, and fill factor of the solar cell are increased, thus improving the photoelectric conversion efficiency of the solar cell.

[0049] In some embodiments, the thickness of the metal element doped in the doped conductive layer 120 is 10nm to 20nm, for example, 10nm, 12nm, 14nm, 15nm, 18nm, 19nm, or 20nm, etc. If the thickness of the metal element doped in the doped conductive layer 120 is too thick, the metal element may further diffuse towards the tunneling layer 130 or the substrate 110, affecting the performance of the tunneling layer 130 and the substrate 110. If the thickness of the portion of the conductive layer 120 doped with the metal element is too thin, the performance improvement of the tandem solar cell is poor, affecting the improvement effect.

[0050] In some embodiments, the concentration of metal elements in the doped conductive layer 120 gradually decreases in the direction from the composite layer 101 to the doped conductive layer 120. That is, the doping concentration is higher near the composite layer 101 and lower near the substrate 110. In this way, a gradient change in doping concentration can be formed in the doped conductive layer 120, thereby avoiding abrupt changes in the doping concentration of metal elements in the doped conductive layer 120, and further improving the reliability of the tandem solar cell.

[0051] In some embodiments, the composite layer 101 is made of indium tin oxide (ITO), and the ratio of tin ion doping concentration to indium ion doping concentration in the doped conductive layer 120 is 7 to 13, for example, 8, 9, 10, 11, 12, or 13. For the doped conductive layer 120, excessively high indium ion doping concentration may lead to excessively high hole concentration, inducing Auger recombination, while excessively high tin ion doping concentration may introduce lattice defects. By utilizing the combined effect of tin and indium ions and controlling the ratio of tin ion to indium ion doping concentration to 7 to 13, the conductivity and recombination loss of the doped conductive layer 120 can be balanced.

[0052] For indium ions, the solid solubility of indium in the doped conductive layer 120 is low, and excessive doping can easily lead to precipitation defects. Tin ions are used to balance the precipitation problem of indium ions, thereby reducing the defect problems caused by indium ion precipitation.

[0053] It is understandable that the indium ion doping concentration and tin ion doping concentration here refer to the average doping concentration of indium ions and tin ions within the doped conductive layer 120.

[0054] Therefore, by setting the thickness of the metal element doped in the doped conductive layer 120 to 10nm~20nm, it is possible to achieve lattice matching between the doped conductive layer 120 and the composite layer 101, reduce the interface defect state density, and avoid affecting other structures of the crystalline silicon bottom cell 100. This improves the performance of the tandem cell while avoiding affecting its reliability.

[0055] The doping elements in the emitter 140 are opposite to those in the substrate 110, thereby forming a PN junction for separating and transporting electrons and holes. The first passivation layer 150 can be a single-layer structure or a stacked structure, and the material of the first passivation layer 150 can be one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0056] In some embodiments, the composite layer 101 may be made of indium tin oxide (ITO), which has high electrical conductivity and can effectively transport charge carriers, reduce the series resistance between the crystalline silicon bottom cell 100 and the perovskite top cell 102, and improve the fill factor. Moreover, ITO has high light transmittance, allowing unabsorbed light to pass between the crystalline silicon bottom cell 100 and the perovskite top cell 102, thereby further improving the light absorption rate.

[0057] In some embodiments, the ratio of tin doping concentration to indium doping concentration in the composite layer 101 is 4 to 19, for example, 5, 7, 9, 10, 12, 14, 16, 18, or 19. In other words, the ratio of tin doping concentration to indium doping concentration in the composite layer 101 is 80:20 to 95:5. The higher the tin doping concentration, the lower the cost required to form the composite layer 101. However, excessively high tin doping concentration can lead to instability in the sputtering process during the formation of the composite layer 101, affecting the reliability of the formed composite layer 101.

[0058] In some embodiments, the material of the composite layer 101 may also be AZO (aluminum-doped zinc oxide), FTO (fluorine-doped tin oxide), or ATO (antimony-doped tin oxide), etc.

[0059] In some embodiments, the perovskite top cell 102 includes: a first transport layer 112, a perovskite substrate 122, a second passivation layer 132, a second transport layer 142, a third transport layer 152, and a transparent conductive layer 162 stacked together.

[0060] The first transport layer 112 can be a hole transport layer, and the material of the first transport layer 112 can be poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), nickel oxide (NiO) x It is composed of materials such as copper thiocyanate (CuSCN).

[0061] The second passivation layer 132 is used to passivate the perovskite substrate 122, thereby repairing the perovskite substrate 122, reducing carrier recombination in the perovskite top cell 102, and thus improving the carrier transport efficiency of the tandem cell.

[0062] The second transport layer 142 and the third transport layer 152 can be electron transport layers, which can be composed of materials such as tin oxide SnOx, titanium dioxide TiO2, C60 and fullerenes and their derivatives including PCBM.

[0063] The transparent conductive layer 162 can be ITO, AZO, FTO or ATO, or a transparent polymer material such as PDMS (polydimethylsiloxane) or PMMA (polymethyl methacrylate).

[0064] In some embodiments, the tandem cell may further include: a back electrode 103 and a front electrode 104, wherein the back electrode 103 is located on the side of the crystalline silicon bottom cell 100 away from the composite layer 101 and is electrically connected to the emitter 140; and the front electrode is located on the side of the perovskite top cell 102 away from the composite layer 101 and is electrically connected to the transparent conductive layer 162.

[0065] When the crystalline silicon bottom cell 100 is a BC cell, since the electrodes of the BC cell are all located on the back of the BC cell, the stacked cell has three-terminal output, that is, three terminal outputs. The three terminal outputs correspond to the two output terminals on the back of the BC cell and the output terminal on the top surface of the perovskite top cell 102.

[0066] In this embodiment, on the one hand, the portion of the doped conductive layer 120 near the composite layer 101 is doped with the same metal element as the metal element in the composite layer 101. This reduces the interface difference between the doped conductive layer 120 and the composite layer 101, improving the reliability of the contact between them. Simultaneously, the doping of the portion of the doped conductive layer 120 near the composite layer 101 with the same metal element reduces the interface porosity of the doped conductive layer 120, achieving passivation of the portion of the doped conductive layer 120, thereby improving the photoelectric conversion efficiency of the tandem solar cell.

[0067] Another embodiment of this disclosure also provides a method for manufacturing a stacked battery. This method can be used to form a stacked battery as described in some or all of the above embodiments. The method for manufacturing a stacked battery provided in another embodiment of this disclosure will be described below with reference to the accompanying drawings. It should be noted that the same or corresponding parts as those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated below.

[0068] refer to Figures 2 to 4 ,in, Figure 2 This is a flowchart illustrating a method for manufacturing a stacked battery according to an embodiment of this disclosure. Figures 3 to 4 This is a schematic diagram showing the structural steps of a method for manufacturing a stacked battery according to an embodiment of this disclosure.

[0069] In some embodiments, the method of fabricating a tandem solar cell may include: S10: providing a crystalline silicon base cell, the crystalline silicon base cell including a substrate and a doped conductive layer located on the surface of the substrate.

[0070] The method for fabricating a tandem solar cell may further include: S11: forming a composite layer located on the surface of a crystalline silicon base cell, the composite layer being made of a metal oxide, wherein, during the formation of the composite layer, the metal elements of the composite layer are controlled to diffuse into the doped conductive layer.

[0071] The fabrication method of the tandem solar cell may include: S12: forming a perovskite top cell, wherein the perovskite top cell is located on the surface of the composite layer 101 away from the crystalline silicon bottom cell.

[0072] By controlling the diffusion of metal elements in the composite layer 101 to the doped conductive layer 120 during the formation of the doped conductive layer 120, the interface difference between the doped conductive layer 120 and the composite layer 101 is reduced, thereby improving the reliability of the contact between the doped conductive layer 120 and the composite layer 101. At the same time, the portion of the doped conductive layer 120 near the composite layer 101 is doped with the same metal element as the metal element in the composite layer 101, reducing the interface porosity of the doped conductive layer 120 and achieving passivation of part of the doped conductive layer 120, thereby improving the photoelectric conversion efficiency of the tandem solar cell.

[0073] refer to Figure 3 and Figure 4 , Figure 3 To provide a structural schematic diagram of the corresponding crystalline silicon bottom cell, Figure 4 This is a schematic diagram of the composite layer formed on the crystalline silicon bottom cell and the perovskite top cell.

[0074] In some embodiments, after the crystalline silicon base cell 100 is formed, the surface of the crystalline silicon base cell 100 can be cleaned with hydrofluoric acid. The surface color of the crystalline silicon base cell 100 can be observed to determine whether it is clean. The concentration of hydrofluoric acid can be 1% to 5%, and the cleaning time can be 10 min to 20 min.

[0075] It is understood that the provided crystalline silicon bottom cell 100 includes: a substrate 110, a tunneling layer 130, a doped conductive layer 120, an emitter 140, and a first passivation layer 150. The same or corresponding descriptions can be referred to the above embodiments, and will not be repeated here.

[0076] In some embodiments, the method of forming the composite layer 101 may include: constructing a magnetic field environment in which the crystalline silicon base cell 100 is located; performing a magnetron sputtering process, the magnetron sputtering process including: providing a target material, bombarding the target material with plasma, and providing an oxidizing gas to bombard the metal elements contained in the target material onto the surface of the doped conductive layer 120 to form the composite layer 101; and controlling the metal elements to be doped into the doped conductive layer 120 during the formation of the composite layer 101. In other words, by adding an additional magnetic field during the formation of the composite layer 101, the density of the plasma is increased when the target is bombarded with plasma. This makes the energy of the metal ions sputtered from the target more uniform and easier to adhere to the surface of the crystalline silicon bottom cell 100, thus forming a denser and more crystalline thin film. On the other hand, the increased magnetic field allows the metal ions to adhere more widely and stably to the surface of the doped conductive layer 120, which can reduce the porosity or amorphous region at the interface between the composite layer 101 and the doped conductive layer 120. This passivates the doped conductive layer 120 while improving the reliability of the composite layer 101, further improving the efficiency of the tandem cell.

[0077] In some embodiments, the magnetic field strength of the magnetic field environment is 0.5T~1.5T, for example, 0.5T, 0.7T, 1T, 1.2T, 1.4T or 1.5T, etc., and the process parameters of magnetron sputtering include: sputtering power of 0.5KW~1KW, for example, 0.5KW, 0.6KW, 0.7KW, 0.8KW, 0.9KW or 1KW, etc., and temperature environment of 350℃~450℃, for example, 350℃, 370℃, 400℃, 420℃, 440℃ or 450℃, etc.

[0078] Regarding magnetic field strength, the higher the magnetic field strength, the greater the kinetic energy of the plasma bombarding the target, which makes it easier to form the composite layer 101. However, if the magnetic field strength is too high, it may lead to excessive energy of the plasma bombarding the target, which may cause over-etching of the target, reduce the target life, and may also cause target contamination, affecting the reliability of the subsequent formation of the composite layer 101.

[0079] Regarding sputtering power and ambient temperature, sputtering power is directly proportional to the rate of composite layer 101 formation. However, excessive power may cause local temperature rise on the target surface, which may lead to target cracking. Conversely, excessively low sputtering power may result in uneven thickness of the composite layer 101. Providing a certain temperature environment can provide sufficient thermal energy to enable atoms deposited on the crystalline silicon bottom cell 100 to overcome the diffusion barrier and migrate to lower energy lattice positions, thus promoting the growth of the composite layer 101. However, if the provided temperature environment is too low, it may cause the crystalline silicon bottom cell 100 to warp.

[0080] In some embodiments, the higher the sputtering power, the lower the ambient temperature can be set. The sputtering power can compensate for the insufficient heat energy, thereby improving the crystallinity of the composite layer 101. The higher the ambient temperature, the lower the sputtering power, thereby avoiding excessive bombardment that could damage the already formed composite layer 101.

[0081] In some embodiments, the process of forming the composite layer 101 further includes: detecting the thickness of the composite layer 101; when the thickness of the formed composite layer 101 is less than 5 nm, the magnetic field strength is a first preset magnetic field strength; when the thickness of the formed composite layer 101 is 5 nm to 20 nm, the magnetic field strength is a second preset magnetic field strength; when the thickness of the formed composite layer 101 is greater than 20 nm, the magnetic field strength is a third preset magnetic field strength, wherein the first preset magnetic field strength is less than the second preset magnetic field strength and less than the third preset magnetic field strength. In other words, different magnetic field strengths are set according to the thickness of the composite layer 101. It can be understood that when the thickness of the composite layer 101 is less than 5nm, a higher magnetic field strength is required to facilitate the formation of the initial thickness of the composite layer 101. When the thickness of the composite layer 101 is 5nm to 20nm, the initial thickness of the composite layer 101 has already been formed. Forming the composite layer 101 on the composite layer 101 is easier than forming the composite layer 101 on the crystalline silicon base cell 100. Therefore, after adjusting the magnetic field strength, a composite layer 101 with better uniformity can also be formed. When the thickness of the composite layer 101 is greater than 20nm, the composite layer 101 has a certain thickness, making it easier to form subsequent composite layers 101.

[0082] Furthermore, when the thickness of the formed composite layer 101 is less than 5 nm, it is formed on the surface of the doped conductive layer 120. The lattice difference between the doped conductive layer 120 and the composite layer 101 is relatively large, requiring a larger magnetic field strength to facilitate the formation of the composite layer 101. A larger magnetic field strength can also improve the uniformity of the formed composite layer 101. The thickness of the formed composite layer 101 is 5 nm to 20 nm. In this process, the composite layer 101 is formed on the surface of the composite layer 101, which reduces the formation difficulty. By reducing the magnetic field strength, the uniformity of the composite layer 101 formed in this process can be balanced with that formed on the surface of the doped conductive layer 120. When the thickness of the formed composite layer 101 is greater than 20 nm, the difficulty of forming subsequent composite layers 101 is the lowest. By further reducing the magnetic field strength, the uniformity between composite layers 101 of different thicknesses can be made relatively uniform, which can improve the reliability of the formed composite layer 101.

[0083] In some embodiments, the thickness of the formed composite layer 101 can be monitored in real time using an in-situ detection device: an integrated plasma spectrometer or a thin film thickness sensor.

[0084] In some embodiments, the method for forming the composite layer 101 includes: providing a laser to irradiate the surface of the doped conductive layer 120; performing a magnetron sputtering process, the magnetron sputtering process including: providing a target material, bombarding the target material with plasma, and providing an oxidizing gas to bombard the metal elements contained in the target material onto the surface of the laser-irradiated doped conductive layer 120 to form the composite layer 101; during the formation of the composite layer 101, controlling the doping of metal elements into the doped conductive layer 120. The laser energy is precisely applied to the deposition interface in the magnetron sputtering process, thereby facilitating the formation of the composite layer 101.

[0085] In some embodiments, the laser wavelength of the laser can be 248nm or 532nm, etc., the laser energy density of the laser is 0.5J / cm² to 5J / cm², for example 0.5J / cm², 1J / cm², 2J / cm², 3J / cm², 4J / cm² or 5J / cm², etc., the pulse frequency can be 20Hz to 50Hz, for example 20Hz, 30Hz, 40Hz or 50Hz, etc., the laser incident angle is 30° to 60°, for example 30°, 45°, 50° or 60°, etc.

[0086] Regarding the laser wavelength, a laser with a wavelength adapted to the absorption characteristics of the composite layer 101 material is selected to facilitate the formation of the composite layer 101. Regarding the energy density, excessive energy density may cause local overheating of the target material, leading to target damage, or damage to the doped polycrystalline silicon layer, while insufficient energy density cannot effectively enhance ion kinetic energy. Regarding the pulse frequency, a higher pulse frequency results in a higher rate of composite layer 101 formation, but an excessively high pulse frequency leads to poor uniformity in the formation of the composite layer 101. Regarding the incident angle, selecting a specific incident angle can optimize energy transfer efficiency.

[0087] In some embodiments, the process of forming a perovskite top solar cell 102 may include: sequentially forming a first transport layer 112, a perovskite substrate 122, a second passivation layer 132, a second transport layer 142, a third transport layer 152, and a transparent conductive layer 162.

[0088] The method for forming the first transport layer 112 may include: weighing a certain mass of hole transport material and dissolving it in a solvent solution, adding a magnetic wave, and completely dissolving the hole transport material in the solvent solution to obtain a reaction solution. Then, an appropriate amount of the reaction solution is dropped onto the surface of the crystalline silicon bottom cell 100, spin-coated at a spin coating rate of 4000 rpm to 5000 rpm for 20 to 30 seconds, and then annealed at 100°C to 140°C for 10 to 20 minutes to complete the preparation of the first transport layer 112.

[0089] In some embodiments, the hole transport material can be a carbazole-based hole transport material, such as 2PACZ, and the solvent solution can be an ethanol solution.

[0090] The method for forming the perovskite substrate 122 may include: after the first transport layer 112 is cooled to room temperature, a certain amount of perovskite solution is spread on the surface of the first transport layer 112, and spin-coated at a spin coating rate of 3000 rpm to 5000 rpm for 20 to 30 seconds, and then annealed at 90°C to 100°C for 10 to 20 minutes to prepare the perovskite substrate 122.

[0091] The perovskite solution was prepared by mixing cesium iodide (CsI), lead iodide (PbI2), lead bromide (PbBr2), formamidinium hydroiodide (FAI), and methylamine iodide (MAI) in a certain molar ratio in N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0092] The method for forming the second passivation layer 132 may include: directly forming the second passivation layer 132 by deposition. The method for forming the second transport layer 142 may include: directly forming the second transport layer 142 on the surface of the second passivation layer 132 using a vapor deposition machine. The method for forming the third transport layer 152 may include: depositing the third transport layer 152 using an atomic layer deposition apparatus. The method for forming the transparent conductive layer 162 may include: forming the transparent conductive layer 162 by providing a target material and bombarding it with plasma using a magnetron sputtering process.

[0093] In some embodiments, a magnetic field environment can be created during the formation of the transparent conductive layer 162, or a laser can be added to improve the density and uniformity of the formed transparent conductive layer 162. The description of creating the magnetic field environment and adding the laser can be found in the section on forming the composite layer 101 described above, and will not be repeated here.

[0094] In some embodiments, the process of forming a tandem cell further includes forming a front electrode and a back electrode. The process of forming the front electrode and the back electrode may include depositing electrode materials on the crystalline silicon bottom cell 100 and the perovskite top cell 102 by vapor deposition, and completing the formation of the front electrode and the back electrode by sintering.

[0095] The tandem battery prepared according to the embodiments of this disclosure has good structural stability and can be stored outdoors for 1000 hours with battery degradation of less than 2%. Refer to Table 1 below, which shows the device performance measured by the tandem battery provided in the embodiments of this disclosure.

[0096]

[0097] Table 1

[0098] It should be noted that the above measurements were performed by adjusting the power of the solar simulator to 100 mW / cm². 2 To simulate the AM1.5G radiation standard, the current and voltage values ​​of the device were read by a power meter. Before measuring the current density-voltage curve, the light intensity was calibrated using the Newport standard. The device adopted a forward and reverse scan mode with a scan rate of 0.05V / s.

[0099] As can be seen from the table above, the open-circuit voltage, fill factor, and photoelectric conversion efficiency of the tandem battery provided in this embodiment are significantly improved, and the short-circuit current is also improved.

[0100] In the comparative example, the tandem solar cell did not control the diffusion of metal elements in the composite layer 101 into the doped conductive layer 120, and no magnetic field environment was constructed or a laser was used during the formation of the composite layer 101.

[0101] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.

Claims

1. A stacked battery, characterized in that, include: A crystalline silicon bottom cell, the crystalline silicon bottom cell comprising a substrate and a doped conductive layer located on the surface of the substrate; A composite layer is located on the surface of the crystalline silicon bottom cell. The composite layer is made of metal oxide. The portion of the doped conductive layer near the composite layer is doped with the same metal element as the metal element in the composite layer. A perovskite top cell, wherein the perovskite top cell is located on the surface of the composite layer away from the crystalline silicon bottom cell; The thickness of the doped conductive layer containing metal elements is 10 nm to 20 nm. In the direction from the composite layer to the doped conductive layer, the concentration of metal elements in the doped conductive layer gradually decreases.

2. The stacked battery according to claim 1, characterized in that, The composite layer is made of indium tin oxide.

3. The stacked battery according to claim 2, characterized in that, The ratio of the doping concentration of tin ions to the doping concentration of indium ions in the doped conductive layer is 7 to 13.

4. The stacked battery according to claim 2, characterized in that, The ratio of tin doping concentration to indium doping concentration in the composite layer is 4 to 19.

5. A method for manufacturing a stacked battery, characterized in that, include: A crystalline silicon base cell is provided, the crystalline silicon base cell comprising a substrate and a doped conductive layer located on the surface of the substrate; A composite layer is formed on the surface of the crystalline silicon bottom cell. The composite layer is made of metal oxide. During the formation of the composite layer, the metal elements of the composite layer are controlled to diffuse into the doped conductive layer. A perovskite top cell is formed, wherein the perovskite top cell is located on the surface of the composite layer away from the crystalline silicon bottom cell; The thickness of the metal element doped in the doped conductive layer is 10 nm to 20 nm. In the direction from the composite layer to the doped conductive layer, the concentration of metal elements in the doped conductive layer gradually decreases.

6. The method for manufacturing a stacked battery according to claim 5, characterized in that, The method of forming the composite layer includes: A magnetic field environment is constructed, and the crystalline silicon bottom cell is located within the magnetic field environment; A magnetron sputtering process is performed, the magnetron sputtering process comprising: providing a target material, bombarding the target material with plasma, and providing an oxidizing gas to bombard the metal elements contained in the target material onto the surface of the doped conductive layer to form the composite layer; During the formation of the composite layer, the metal element is controlled to be doped into the doped conductive layer.

7. The method for manufacturing a stacked battery according to claim 6, characterized in that, The magnetic field strength of the magnetic field environment is 0.5T~1.5T, and the process parameters of the magnetron sputtering include: sputtering power of 0.5KW~1KW and temperature environment of 350℃~450℃.

8. The method for manufacturing a stacked battery according to claim 6, characterized in that, The process of forming the composite layer also includes: detecting the thickness of the composite layer; When the thickness of the composite layer is less than 5 nm, the magnetic field strength is the first preset magnetic field strength. When the thickness of the composite layer is 5nm~20nm, the magnetic field strength is the second preset magnetic field strength; When the thickness of the composite layer is greater than 20 nm, the magnetic field strength is a third preset magnetic field strength, wherein the first preset magnetic field strength is less than the second preset magnetic field strength and the third preset magnetic field strength.

9. The method for manufacturing a stacked battery according to claim 5, characterized in that, The method of forming the composite layer includes: providing a laser that irradiates the surface of the doped conductive layer; A magnetron sputtering process is performed, the magnetron sputtering process comprising: providing a target material, bombarding the target material with plasma, and providing an oxidizing gas to bombard the metal elements contained in the target material onto the surface of the doped conductive layer irradiated by the laser, so as to form the composite layer; During the formation of the composite layer, the metal element is controlled to be doped into the doped conductive layer.

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