Tandem solar cell and preparation method

Abstract

The present invention provides a tandem solar cell and a preparation method for the tandem solar cell. The tandem solar cell comprises a front electrode, a first tandem layer, a tunnel recombination layer, a second tandem layer, and a back electrode. A first deposited metal layer is arranged between the front electrode and the first tandem layer, and is used for improving the adhesion between a metal slurry and the cell in the process of preparing a tandem cell electrode at a low temperature, and reducing contact resistance between the cell and the metal slurry, thereby improving the conductivity between the metal electrode and perovskite.

Description

A tandem solar cell and its fabrication method Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a tandem solar cell and a method for preparing a tandem solar cell. Background Technology

[0002] Organic-inorganic metal halide perovskite materials, with their excellent photoelectric properties and low cost, are suitable as light-absorbing layers in solar cells. Furthermore, the tunable bandgap of perovskite materials allows them to be stacked with other photovoltaic materials of different bandgap to form tandem solar cells, achieving extremely high photoelectric conversion efficiencies. Tandem solar cells of perovskite and crystalline silicon can effectively improve the conversion efficiency of solar cells.

[0003] In existing technologies, directly using high-temperature crystalline silicon to prepare electrodes for tandem solar cells leads to decreased repeatability and stability. Therefore, low-temperature sintering is typically employed in the fabrication of perovskite-silicon tandem solar cells. However, printing pastes contain polymers, and directly printing metal pastes results in poor adhesion between the paste and the cell, significant loss of the cell's fill factor, and severely impacts contact resistance and conductivity.

[0004] In order to overcome the above-mentioned defects in the existing technology, there is an urgent need in the field for a tandem solar cell technology to improve the adhesion between the metal paste and the cell and reduce the contact resistance between the cell and the metal paste during the low-temperature preparation of tandem cell electrodes, thereby improving the conductivity between the metal electrode and the perovskite. Summary of the Invention

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed descriptions that follow.

[0006] To overcome the aforementioned deficiencies in the existing technology, the present invention provides a tandem solar cell and a method for preparing a tandem solar cell, which improves the adhesion between the metal paste and the cell and reduces the contact resistance between the cell and the metal paste during the low-temperature preparation of the tandem cell electrode, thereby enhancing the conductivity between the metal electrode and the perovskite.

[0007] Specifically, the tandem solar cell provided according to the first aspect of the present invention includes a positive electrode, a first tandem layer, a tunneling composite layer, a second tandem layer and a back electrode, wherein a first deposited metal layer is provided between the positive electrode and the first tandem layer.

[0008] Furthermore, in some embodiments of the present invention, the metallic material comprises one selected from silver, gold, copper, aluminum, iron, chromium, and molybdenum, or an alloy selected from two or more metals selected from silver, gold, copper, aluminum, iron, chromium, and molybdenum. Furthermore, in some embodiments of the present invention, the first deposited metallic layer comprises 85% to 95% of the metallic material by mass.

[0009] Furthermore, in some embodiments of the present invention, the thickness of the first deposited metal layer is 5 nm to 2000 nm.

[0010] Furthermore, in some embodiments of the present invention, the first deposited metal layer comprises silver, and the thickness of the first deposited metal layer is 20 nm to 2000 nm; or the first deposited metal layer comprises a metal material selected from gold, copper, aluminum, iron, chromium, molybdenum or silver-copper alloy, and the thickness of the first deposited metal layer is 20 nm to 200 nm respectively.

[0011] Furthermore, in some embodiments of the present invention, the first deposited metal layer is a multilayer structure, which is formed by depositing multiple layers of the metal material.

[0012] Furthermore, in some embodiments of the present invention, the first deposited metal layer comprises a gold-silver bilayer structure or an aluminum-iron bilayer structure.

[0013] Furthermore, in some embodiments of the present invention, the thickness of the gold-silver double-layer structure or the aluminum-iron double-layer structure is 20nm to 200nm.

[0014] Furthermore, in some embodiments of the present invention, the thickness of the gold-deposited metal layer in the gold-silver bilayer structure is equal to the thickness of the silver-deposited metal layer, or the thickness of the aluminum-deposited metal layer in the gold-silver bilayer structure is equal to the thickness of the iron-deposited metal layer.

[0015] Furthermore, in some embodiments of the present invention, the deposition process of the first deposited metal layer includes at least one of thermal evaporation deposition, ion beam deposition, reactive plasma deposition, electron beam deposition, and sputtering deposition, and the first deposited metal layer is deposited between the positive electrode and the first stack via the deposition process.

[0016] Furthermore, in some embodiments of the present invention, the first deposited metal layer is formed by electron beam deposition, and: the first deposited metal layer is silver with a thickness of 20 nm to 2000 nm; the first deposited metal layer adopts a gold-silver bilayer structure with a thickness of 20 nm to 200 nm; or the first deposited metal layer adopts a silver-copper alloy with a thickness of 20 nm to 200 nm.

[0017] Furthermore, in some embodiments of the present invention, the first deposited metal layer has a pattern consistent with the metal grid lines between the first stacked layers.

[0018] Furthermore, in some embodiments of the present invention, the stacked solar cell further includes a second deposited metal layer disposed between the back electrode and the second stack.

[0019] Furthermore, in some embodiments of the present invention, the first stack includes a hole transport layer, a first light-absorbing layer, an electron transport layer and a first transparent conductive layer, the tunneling composite layer is a transparent conductive oxide layer, and the second stack includes a second transparent conductive layer and a second light-absorbing layer.

[0020] Furthermore, the method for fabricating a tandem solar cell according to a second aspect of the present invention includes the following steps: fabricating a second tandem layer of the tandem solar cell, the second tandem layer having opposing first and second surfaces, the second surface being a light-receiving surface; forming a tunneling composite layer on the second surface of the second tandem layer; forming a first tandem layer on the surface of the tunneling composite layer away from the second tandem layer; forming a first deposited metal layer on the surface of the first tandem layer away from the tunneling composite layer; and forming a positive electrode on the surface of the first deposited metal layer away from the first tandem layer, and forming a back electrode on the surface of the second tandem layer away from the tunneling composite layer. Attached Figure Description

[0021] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0022] Figure 1 shows a schematic diagram of the structure of a stacked solar cell provided according to some embodiments of the present invention.

[0023] Figure 2 shows a schematic flowchart of a method for fabricating a tandem solar cell according to some embodiments of the present invention.

[0024] Figure 3 shows a material schematic diagram of a tandem solar cell provided according to some embodiments of the present invention.

[0025] Reference numerals: 110 Back electrode; 111 Second stacked layer; 1111 Second transparent conductive layer; 1112 Second light-absorbing layer; 112 Tunneling composite layer; 113 First stacked layer; 1131 Hole transport layer; 1132 First light-absorbing layer; 1133 Electron transport layer; 1134 First transparent conductive layer; 114 Positive electrode; 120 First deposited metal layer; 121 Second deposited metal layer. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a thorough understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Furthermore, the terms "upper," "lower," "left," "right," "top," "bottom," "horizontal," and "vertical" used in the following description should be understood as the orientations shown in the relevant paragraphs and accompanying drawings. These relative terms are for illustrative purposes only and do not imply that the described apparatus must be manufactured or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0029] It is understood that although terms such as "first," "second," and "third" may be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first components, regions, layers, and / or parts discussed below may be referred to as second components, regions, layers, and / or parts without departing from some embodiments of the present invention.

[0030] As mentioned above, in the prior art, directly using high-temperature crystalline silicon to prepare electrodes for tandem solar cells leads to a decrease in cell repeatability and stability. Therefore, low-temperature sintering is typically used in the fabrication of perovskite crystalline silicon tandem solar cells. However, this low-temperature sintering method results in poor conductivity of the metal electrodes, thus consuming a large amount of material used for electrode preparation (e.g., silver paste).

[0031] In order to overcome the above-mentioned defects in the prior art, the present invention provides a tandem solar cell, which improves the adhesion between the metal paste and the cell during the low-temperature preparation of the tandem cell electrode, thereby improving the conductivity of the metal electrode and reducing the amount of metal paste used.

[0032] In some non-limiting embodiments, the method for preparing the tandem solar cell provided in the second aspect of the present invention can be implemented based on the tandem solar cell provided in the first aspect of the present invention.

[0033] Please refer to Figure 1 for details. Figure 1 shows a schematic diagram of the structure of a stacked solar cell provided according to some embodiments of the present invention.

[0034] As shown in Figure 1, the tandem solar cell includes a positive electrode 114, a first tandem layer 113, a tunneling composite layer 112, a second tandem layer 111, and a back electrode 110, wherein a first deposited metal layer 120 is provided between the positive electrode 114 and the first tandem layer 113.

[0035] In some embodiments, the tandem solar cell further includes a second deposited metal layer 121 disposed between the back electrode 110 and the second stack 111.

[0036] In some embodiments, the first deposited metal layer 120 comprises a metallic material, which includes one selected from silver, gold, copper, aluminum, iron, chromium, and molybdenum, or an alloy of two or more of silver, gold, copper, aluminum, iron, chromium, and molybdenum. Here, the first deposited metal layer should be understood as a single-layer structure, and the metallic material contained in this single-layer structure may be selected from one selected from silver, gold, copper, aluminum, iron, chromium, and molybdenum, or an alloy of two or more of silver, gold, copper, aluminum, iron, chromium, and molybdenum.

[0037] In some embodiments, the first deposited metal layer 120 comprises 85% to 95% by mass of a metallic material. It may also comprise 5% to 15% by mass of epoxy resin and organic additives.

[0038] In some embodiments, the thickness of the first deposited metal layer 120 is 5 nm to 2000 nm.

[0039] In some embodiments, the metal material of the first deposited metal layer 120 may include silver, and the thickness of the silver-containing first deposited metal layer may be 20 nm to 2000 nm. Here, since a thickness of less than 20 nm may result in incomplete metal plating, i.e., discontinuous plating, choosing a thickness range greater than 20 nm not only ensures the stability of the plating but also obtains the optimal metal resistivity, thereby improving the overall performance of the solar cell.

[0040] Optionally, the thickness of the silver can be from 20 nm to 100 nm. Here, since the resistivity change is generally small above 100 nm, this thickness range not only ensures the stability of the coating, but also saves on the amount of metal paste used, thereby reducing manufacturing costs.

[0041] In some embodiments, the metal material of the first deposited metal layer 120 further includes a metal material selected from gold, copper, aluminum, iron, chromium, molybdenum, or a silver-copper alloy, wherein the thickness of the first deposited metal layer is 20 nm to 200 nm.

[0042] Here, since thicknesses below 20 nm may result in incomplete metal plating (i.e., discontinuous plating), selecting a thickness range greater than 20 nm not only ensures plating stability but also achieves optimal metal electrode contact resistivity, thereby improving the overall performance of the solar cell. Since the change in metal electrode contact resistivity is typically small above 200 nm, this thickness range not only ensures plating stability but also saves on metal paste usage, thus reducing manufacturing costs.

[0043] Here, since conventional gold, silver, and copper have relatively good conductivity, the change in resistivity of their metal electrode contacts is relatively small as the thickness increases after 20nm. However, aluminum, iron, chromium, and molybdenum have poorer conductivity, so compared with gold, silver, and copper, the change in resistivity of their metals is relatively large when the thickness is increased by the same amount, and the conductivity is improved more.

[0044] In some embodiments, the second stack 111 of the tandem solar cell includes a second transparent conductive layer 1111 and a second light-absorbing layer 1112. Here, the second transparent conductive layer 1111 is typically a transparent conductive oxide thin film (e.g., ITO, IZO, IWO), which allows light to pass through and simultaneously serves as the anode. The second light-absorbing layer 1112 may include at least one of crystalline silicon, perovskite, CdTe, CIGS, and GaAs materials. Furthermore, the second light-absorbing layer 1112 may also employ a heterojunction with an intrinsic thin-layer (HJT) cell, thereby reducing fabrication steps and improving fabrication efficiency.

[0045] In some embodiments, the tunneling composite layer 112 of the tandem solar cell may be at least one of ITO, IWO and Ag to help electrons pass through the material layers more quickly, reduce electron recombination losses inside the material, thereby improving the electron transport efficiency and overall performance of the cell.

[0046] In some embodiments, the first stack 113 of the tandem solar cell includes a hole transport layer 1131, a first light-absorbing layer 1132, an electron transport layer 1133, and a first transparent conductive layer 1134.

[0047] In some embodiments, in the first stack 113 of the solar cell, the hole transport layer 1131 may include a self-assembled monolayer and an anchoring layer. Specifically, the anchoring layer includes ITO, IZO, IWO, FTO, ICO, AZO, BZO, nanocrystalline silicon, TiO2, SnO2, and NiO. x and AlO x At least one of the following. The self-assembled monolayer in the hole transport layer 1131 includes at least one of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), benzoic acid, and 4-[bis(2,4-dimethoxybiphenyl-4-yl)amino]-biphenyl-4-carboxylic acid (MC-43).

[0048] Those skilled in the art will understand that the structure of the hole transport layer 1131 described above is only a non-limiting embodiment provided by the present invention, intended to clearly demonstrate the main concept of the present invention and provide a specific solution that is easy for the public to implement, rather than being used to limit the scope of protection of the present invention.

[0049] Optionally, in some other embodiments, the hole transport layer 1131 in the first stack 113 of the solar cell may further include a plurality of p-type layers for transporting holes, wherein the p-type layer material includes at least one of p-type monocrystalline silicon, p-type polycrystalline silicon, p-type amorphous silicon and single-molecule self-assembled material, and its thickness is not greater than 100 μm.

[0050] In some embodiments, the first light-absorbing layer 1132 may be made of perovskite material to absorb photons and generate electron-hole pairs. The perovskite material has a three-dimensional structure ABX3, where A is a monovalent cation, B is a divalent cation, and X is a monovalent anion. The monovalent cation A includes, but is not limited to, one or more of the following monovalent cations: cesium (Cs), rubidium (Rb), methylamino (CH3NH3), and formamidinyl (CH2NH2)2. The divalent cation B includes, but is not limited to, one or more of the following divalent cations: lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), and calcium (Ca). The monovalent anion X includes, but is not limited to, one or more of the following monovalent anions: iodine (I), bromine (Br), chloride (Cl), fluorine (F), and thiocyanate (SCN). Here, perovskite materials can be coated onto a self-assembled monolayer using at least one of the following methods: blade coating, slot coating, screen printing, and inkjet printing. The thickness of this layer can be 10 nm to 100 μm, and the band gap can be 0.9 eV to 3.0 eV. Before preparation, the perovskite precursor is usually mixed with various solvents to obtain a perovskite precursor solution, wherein the molar ratio of each solvent to the precursor complex is (0.001 to 1).

[0051] In some embodiments, the electron transport layer 1133 may further include a plurality of n-type layers for transporting electrons, wherein the n-type layer materials include n-type monocrystalline silicon, n-type polycrystalline silicon, n-type amorphous silicon, TiO2, SnO2, ZnO, ZrO2, GZO, IZO, FTO, ITO, BaSnO3, and TiSnO. x SnZnO x At least one of fullerenes and their derivatives, with a thickness not exceeding 100 μm.

[0052] In some embodiments, the first transparent conductive layer 1134 is typically a transparent conductive oxide film (e.g., ITO, IZO, IWO) that can be used to allow light to pass through, serving as a cathode.

[0053] In some embodiments, the metal paste of the positive electrode 114 and / or the back electrode 110 is made of at least one of Au, Ag, Al, Cu, graphene, TCO and nanocrystalline silicon, and its thickness may not exceed 10 μm.

[0054] In some embodiments, the first deposited metal layer 120 can be deposited before printing the metal paste, which is used to improve the adhesion between the metal paste and the battery during the low-temperature preparation of the tandem battery electrode, thereby improving the conductivity of the metal electrode and reducing the amount of metal paste used.

[0055] In some embodiments, the deposition process of the first deposited metal layer 120 includes at least one of thermal evaporation deposition, ion beam deposition, reactive plasma deposition, electron beam deposition, and sputtering deposition, and the first deposited metal layer 120 is deposited between the positive electrode 114 and the first stack 113 via the deposition process. The first deposited metal layer 120 may have a pattern consistent with the metal gate lines between the first stack 113.

[0056] Furthermore, the vacuum pressure of the thermal evaporation deposition process is 4 × 10⁻⁶. -4 torr, voltage 3V, current 160A, evaporation rate is The vacuum pressure for reactive plasma deposition is 3 × 10⁻⁶. -5 The electron gun has a current of 130A, an argon flow rate of 40 sccm, and argon as the protective gas in the chamber. The evaporation rate is... The vacuum pressure for electron beam deposition is 4 × 10⁻⁶. -4 Torr, voltage 20kV, single gun power 70W~100W, evaporation rate is

[0057] Furthermore, in some embodiments, the first deposited metal layer 120 can be formed by electron beam deposition, and: the first deposited metal layer 120 can be made of silver and its thickness is set to 20nm to 2000nm; the first deposited metal layer 120 can be a gold-silver bilayer structure and its thickness is set to 20nm to 200nm; the first deposited metal layer 120 can be made of silver-copper alloy and its thickness is set to 20nm to 200nm.

[0058] In some embodiments, the first deposited metal layer 120 is a multilayer structure, formed by depositing multiple layers of metal materials. The metal layer materials included in the multilayer structure may be selected from one of the aforementioned silver, gold, copper, aluminum, iron, chromium, and molybdenum, or an alloy of two or more of these metals. Preferably, the first deposited metal layer 120 may include a gold-silver bilayer structure or an aluminum-iron bilayer structure. The thickness of the gold-silver bilayer structure or the aluminum-iron bilayer structure is 20 nm to 200 nm. In the gold-silver bilayer structure, the thickness of the gold deposited metal layer is equal to the thickness of the silver deposited metal layer, or the thickness of the aluminum deposited metal layer is equal to the thickness of the iron deposited metal layer.

[0059] Here, the multilayer metal layer structure can reduce the resistance of the first deposited metal layer 120. Specifically, this multilayer metal layer structure can reduce the contact resistance with the metal electrode while depositing a more stable metal, thereby improving stability.

[0060] The working principle of the above-mentioned tandem solar cell will be described below with reference to some embodiments of the fabrication methods of tandem solar cells. Those skilled in the art will understand that these embodiments of tandem solar cell methods are merely non-limiting implementations provided by the present invention, intended to clearly demonstrate the main concepts of the invention and provide some specific solutions convenient for public implementation, rather than being intended to limit all fabrication methods of the tandem solar cell.

[0061] Please refer to Figures 2 and 3. Figure 2 shows a schematic flowchart of a method for fabricating a tandem solar cell according to some embodiments of the present invention. Figure 3 shows a schematic diagram of the materials used in the tandem solar cell according to some embodiments of the present invention.

[0062] As shown in Figures 2 and 3, the method for preparing the tandem solar cell can first perform step S1: preparing the second stack 111 of the tandem solar cell, the second stack 111 having a first surface and a second surface opposite to each other, the second surface being the light-receiving surface.

[0063] Specifically, the fabrication method of the second light-absorbing layer 1112 first involves selecting an N-type silicon wafer; then, an intrinsic amorphous silicon layer and an N-type amorphous silicon layer are sequentially fabricated on the second surface of the N-type silicon wafer, wherein the N-type amorphous silicon layer serves as the second surface of the second light-absorbing layer 1112; and finally, an intrinsic amorphous silicon layer and a P-type amorphous silicon layer are sequentially fabricated on the first surface of the N-type silicon wafer, wherein the P-type amorphous silicon layer serves as the first surface of the second light-absorbing layer 1112. For example, the maximum height h of the surface traces on the N-type silicon wafer can be 5 μm, and the maximum tilt angle θ of the surface traces on the N-type silicon substrate is 30°. Then, an intrinsic amorphous silicon layer with a thickness of 5 nm and an N-type amorphous silicon layer with a thickness of 20 nm are sequentially fabricated on the second surface of the N-type silicon wafer using PECVD. Finally, an intrinsic amorphous silicon layer with a thickness of 5 nm and a P-type amorphous silicon layer with a thickness of 20 nm are sequentially fabricated on the first surface of the N-type silicon wafer using PECVD. Next, a second transparent conductive layer 1111 is prepared on the first surface of the second light-absorbing layer 1112. For example, a transparent conductive oxide layer ITO with a thickness of 130 nm is prepared on the surface of the P-type amorphous silicon layer away from the N-type silicon wafer using a sputtering method.

[0064] Subsequently, the method for fabricating the tandem solar cell can first perform step S2: forming a tunneling composite layer 112 on the second surface of the second tandem layer 111.

[0065] Specifically, the tunneling composite layer 112 can be prepared on the second surface of the second light-absorbing layer 1112 by sputtering a transparent conductive oxide layer ITO on the surface of the N-type amorphous silicon layer away from the N-type silicon wafer, with a thickness of 50 nm.

[0066] Subsequently, the method for fabricating a tandem solar cell can perform step S3: forming a first tandem layer 113 on the surface of the tunneling composite layer 112 away from the second tandem layer 111.

[0067] Specifically, a NiO layer with a thickness of 30 nm was prepared on the surface of the second surface tunneling composite layer 112 (transparent conductive oxide layer) ITO using magnetron sputtering. Then, a perovskite light-absorbing layer Cs was formed on the surface of the NiO layer using solution spin coating. 0.25 FA 0.75 Pb(I 0.8 Br 0.2 )3, with a band gap of approximately 1.68 eV and a thickness of 500 nm. Subsequently, a 15 nm thick C layer was prepared on the surface of the perovskite light-absorbing layer using a thermal evaporation method. 60 Layers, and the use of atomic layer deposition in C 60 A SnO2 layer with a thickness of 15 nm was prepared on the surface of the first layer. Then, an ITO layer with a thickness of 100 nm was prepared on the surface of the SnO2 layer by sputtering.

[0068] Optionally, C is prepared on the surface of the perovskite light-absorbing layer. 60 Before the electrode layer, a 2nm thick LiF layer can be prepared to prevent oxidation or corrosion of the electrode surface, thereby reducing losses during the energy conversion process inside the solar cell and improving the stability and lifespan of the solar cell.

[0069] Subsequently, the method for fabricating a tandem solar cell can perform step S4: forming a first deposited metal layer 120 on the surface of the first tandem layer 113 away from the tunneling composite layer 112.

[0070] Finally, the method for fabricating a tandem solar cell can perform step S5: forming a positive electrode 114 on the surface of the first deposited metal layer 120 away from the first tandem layer 113, and forming a back electrode 110 on the surface of the second tandem layer 111 away from the tunneling composite layer 112.

[0071] Optionally, a second deposited metal layer 121 may be prepared before forming the back electrode 110 on the surface of the second stack 111 away from the tunneling composite layer 112. Here, the physicochemical characteristics of the second deposited metal layer are the same as those of the first metal layer, and will not be described again.

[0072] Please refer to Table 1, which shows an embodiment and a comparative example of the performance parameters of the stacked battery with a first deposited metal layer 120.

[0073] As shown in Table 1, in the comparative example, the stacked battery does not have a first deposited metal layer 120. Therefore, the contact resistivity between the metal electrode and the battery is the highest (60 Ω·cm). Specifically, during low-temperature sintering of the metal paste in the metal electrode, the incomplete sintering of the resin and other organic materials leads to poor contact between the metal electrode and the battery.

[0074] Furthermore, since the printing paste of the metal electrode contains a small amount of non-conductive organic matter, directly printing the metal electrode will result in a high contact resistance between the electrode and the battery. However, after depositing the metal layer, the contact resistance between the deposited metal layer and the battery decreases. Moreover, the large number of metal particles in the printing electrode paste will not generate contact resistance with the deposited metal layer. Therefore, the overall contact resistance decreases, which directly leads to a sharp increase in the fill factor in the battery performance, resulting in a significant improvement in the conversion efficiency of the device.

[0075] In summary, the tandem solar cell provided by this invention can be used to improve the adhesion between the metal electrode and the cell during the low-temperature preparation of tandem cell electrodes, thereby improving the conductivity of the metal electrode and thus increasing the fill factor of the tandem cell.

[0076] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0077] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A stacked solar cell, characterized by, The tandem solar cell includes a positive electrode, a first tandem layer, a tunneling composite layer, a second tandem layer, and a back electrode, wherein a first deposited metal layer is provided between the positive electrode and the first tandem layer.

2. The tandem solar cell of claim 1, wherein The first deposited metal layer comprises a metallic material, wherein the metallic material includes one selected from silver, gold, copper, aluminum, iron, chromium, and molybdenum. Or an alloy selected from two or more metals including silver, gold, copper, aluminum, iron, chromium, and molybdenum.

3. The tandem solar cell of claim 2, wherein, The first deposited metal layer comprises 85% to 95% of the metal material by mass.

4. The tandem solar cell of claim 2, wherein, The thickness of the first deposited metal layer is 5 nm to 2000 nm.

5. The tandem solar cell of claim 4, wherein, The first deposited metal layer comprises silver, and the thickness of the first deposited metal layer is 20 nm to 2000 nm; or the first deposited metal layer comprises a metal material selected from gold, copper, aluminum, iron, chromium, molybdenum or silver-copper alloy, and the thickness of the first deposited metal layer is 20 nm to 200 nm.

6. The tandem solar cell of claim 2, wherein, The first deposited metal layer has a multi-layer structure, which is formed by depositing multiple layers of the metal material.

7. The tandem solar cell of claim 6, wherein, The first deposited metal layer includes a gold-silver bilayer structure or an aluminum-iron bilayer structure.

8. The tandem solar cell of claim 7, wherein, The thickness of the gold-silver double-layer structure or the aluminum-iron double-layer structure is 20nm to 200nm.

9. The tandem solar cell of claim 8, wherein, In the gold-silver bilayer structure, the thickness of the gold deposited metal layer is equal to the thickness of the silver deposited metal layer, or the thickness of the aluminum deposited metal layer is equal to the thickness of the iron deposited metal layer.

10. The tandem solar cell according to any one of claims 1 to 9, wherein The deposition process of the first deposited metal layer includes at least one of thermal evaporation deposition, ion beam deposition, reactive plasma deposition, electron beam deposition, and sputtering deposition, and the first deposited metal layer is deposited between the positive electrode and the first stacked layer via the deposition process.

11. The tandem solar cell of claim 1, wherein, The first deposited metal layer is formed by electron beam deposition, and: The first deposited metal layer is made of silver, and its thickness is set to be 20 nm to 2000 nm. The first deposited metal layer adopts a gold-silver bilayer structure, and its thickness is set to 20nm~200nm; The first deposited metal layer is made of silver-copper alloy and its thickness is set to 20nm to 200nm.

12. The tandem solar cell of claim 1, wherein, The first deposited metal layer has a pattern consistent with the metal grid lines between the first stacked layers.

13. The tandem solar cell of claim 1, wherein, It also includes a second deposited metal layer disposed between the back electrode and the second stack.

14. The tandem solar cell of claim 1, wherein, The first stack includes a hole transport layer, a first light-absorbing layer, an electron transport layer, and a first transparent conductive layer. The tunneling composite layer is a transparent conductive oxide layer. The second stack includes a second transparent conductive layer and a second light-absorbing layer.

15. A method for producing the laminated solar cell according to any one of claims 1 to 14, characterized by, Includes the following steps: A second stack of the tandem solar cell is prepared, the second stack having opposing first and second surfaces, the second surface being the light-receiving surface; A tunneling composite layer is formed on the second surface of the second stack; A first stack is formed on the surface of the tunneling composite layer that is away from the second stack. A first deposited metal layer is formed on the surface of the first stack away from the tunneling composite layer; as well as A positive electrode is formed on the surface of the first deposited metal layer away from the first stack, and a back electrode is formed on the surface of the second stack away from the tunneling composite layer.

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