CN118315395A

CN118315395A - Laminated solar cell, preparation method and application thereof

Info

Publication number: CN118315395A
Application number: CN202410402004.6A
Authority: CN
Inventors: 徐业; 崔标; 张学玲
Original assignee: Trina Solar Co Ltd
Current assignee: Trina Solar Co Ltd
Priority date: 2024-04-03
Filing date: 2024-04-03
Publication date: 2024-07-09

Abstract

The invention relates to a laminated solar cell, a preparation method and application thereof. The stacked solar cell includes a top solar cell and a bottom solar cell stacked in a first direction; the cross-sectional area S ₁ of the top solar cell along a second direction is less than or equal to the cross-sectional area S ₂ of the bottom solar cell, wherein the second direction is perpendicular to the first direction; the top solar cell has a wider bandgap than the bottom solar cell; the top solar cell comprises a photovoltaic active layer, wherein the material of the photovoltaic active layer is an inorganic semiconductor material. The laminated solar cell has low preparation cost, high stability and high photoelectric conversion efficiency, and has wide application prospect.

Description

Laminated solar cell, preparation method and application thereof

Technical Field

The invention relates to the field of photovoltaics, in particular to a laminated solar cell, and a preparation method and application thereof.

Background

Solar energy is a clean energy source which is rich in resources and does not need to be transported, is hopeful to become an alternative energy source of traditional fossil fuel, and the development of solar energy collection and conversion technology has gradually become a research focus. Photovoltaic devices can directly convert solar energy into electrical energy, and are one of the most efficient ways to utilize solar energy. So far, the installed demand for photovoltaic devices worldwide is continuously increasing.

With the continuous development of photovoltaic technology, the efficiency of a single-cell silicon battery is about to reach the theoretical upper limit. In order to further improve the energy conversion efficiency of the photovoltaic cell, the concept of multi-junction cells is proposed, further breaking through the thermal relaxation losses of single cells. At present, a wide-bandgap perovskite battery is superimposed on a crystalline silicon battery, so that the energy conversion efficiency of 33.9% can be realized, the energy conversion efficiency is far higher than that of the existing single crystalline silicon battery (26.81%), and the excellent performance advantage of a multi-junction battery is shown. However, the material of the photoelectric conversion layer of the perovskite battery is an ionic crystal, is extremely sensitive to environmental stresses such as water vapor, high temperature, an electric field and the like, and has a decay rate far higher than that of a Shan Jiejing silicon battery in actual work, so that the technology also needs to be improved in stability and can be practically applied. In addition to perovskite-crystalline silicon laminated cells, two-junction, three-junction or more-junction laminated cells made of III-V semiconductors have been used for space applications to make breakthroughs, and the energy conversion efficiency is high, however, the extremely high cost of the technology limits the large-scale application of the laminated cells. Therefore, a multi-junction cell with high efficiency and environmental aging resistance is a necessary development path of future photovoltaic technology, and meanwhile, the technology also needs to meet the precondition that the cost cannot be excessively high for mass production, but the related technology has not been reported yet.

Disclosure of Invention

In view of the above, the present invention provides a novel, low-cost, stacked solar cell having both high stability and high photoelectric conversion efficiency.

The technical proposal is as follows:

in one aspect of the present invention, there is provided a stacked solar cell including a top solar cell and a bottom solar cell stacked in a first direction;

The cross-sectional area S ₁ of the top solar cell along a second direction is less than or equal to the cross-sectional area S ₂ of the bottom solar cell, wherein the second direction is perpendicular to the first direction;

the top solar cell has a wider bandgap than the bottom solar cell;

The top solar cell comprises a photovoltaic active layer, wherein the material of the photovoltaic active layer is an inorganic semiconductor material.

In some of these embodiments, the cross-sectional area of the bottom solar cell is greater than the cross-sectional area of the top solar cell.

In some of these embodiments, at am1.5g, the top solar cell has a short circuit current density of a and the bottom solar cell has a short circuit current density of b;

S ₁、S₂, a and b satisfy:

b≤2a＜2b，S₂=（2a/b）*S₁；

Wherein a and b are in units of mA/cm ²,S₁ and S ₂ are in units of cm ².

In some of these embodiments, the inorganic semiconductor material has a bandgap of 1.2eV to 1.8eV.

In some embodiments, the inorganic semiconductor material is selected from Se, te, ge, and one or more of the following formulas (1) - (3):

Formula (1): a1 _x1B1_(1-x1)C1_y1D1_(1-y1);

Formula (2): A2A 2 _x2B2_(1-x2)C2_y2D2_(1-y2)E_2zF_2(1-z)

Formula (3): sb ₂S_3x3Se_3(1-x3);

wherein the A1 position is selected from one or more of Zn ²⁺、Mg²⁺、Mn²⁺、Ca²⁺、Ba²⁺ and Cu ²⁺;

The B1 position is selected from one or more of Zn ²⁺、Mg²⁺、Mn²⁺、Ca²⁺、Ba²⁺、Cu²⁺ and Cd ²⁺;

The C1 position is selected from one or more of O ^2-、S^2- and Se ^2-;

The D1 position is selected from one or more of O ^2-、S^2-、Se^2- and Te ^2-;

The A2 position is selected from one or more of Ag ⁺、Au⁺、Cs⁺ and Rb ⁺; the B2 position is selected from one or more of Ag ⁺、Au⁺、Cs⁺、Rb⁺ and Cu ⁺;

the C2 position is selected from one or more of Fe ³⁺、Cr³⁺、Co³⁺、Al³⁺、In³⁺ and Ga ³⁺;

The D2 position is selected from one or more of Fe ³⁺、Cr³⁺、Co³⁺、Al³⁺、In³⁺ and Ga ³⁺;

The E position and the F position are respectively and independently selected from one or more of O ^2-、S^2-、Se^2- and Te ^2-;

0≤x1<1，0≤y1<1，0≤x2<1，0≤y2<1，0≤z<1，0≤x3≤1。

In some of these embodiments, the inorganic semiconductor material comprises one or more of Zn_x1Cd_(1-x1)Te、Mg_x1Cd_(1-x1)Te、Mn_x1Cd_(1-x1)Te、CdTe、AgInS₂、CuInS₂、CuIn_yGa_1-yS₂、CuIn_yGa_1-ySe₂、CuGaSe₂、AgGaSe₂ and Sb ₂S_3x3Se_3(1-x3).

In some embodiments, the top solar cell comprises a first electrode layer, an electron transport layer, and a photovoltaic active layer disposed in sequence along the first direction, wherein the photovoltaic active layer is closest to the bottom solar cell and the first electrode layer is furthest from the bottom solar cell;

The bottom solar cell comprises a first silicon layer, a crystalline silicon substrate, a second silicon layer and a second electrode layer which are sequentially stacked along the first direction, wherein the first silicon layer is closest to the top solar cell, and the second electrode layer is farthest from the top solar cell;

The first silicon layer is an N-type doped polycrystalline silicon layer, an N-type doped microcrystalline silicon layer or a first amorphous silicon layer;

the second silicon layer is a first P-type doped polycrystalline silicon layer, a P-type doped microcrystalline silicon layer, a second amorphous silicon layer or a P-type diffusion layer.

In some of these embodiments, the material of the first electrode layer includes a metal having conductive properties and an alloy thereof.

In some embodiments, the first electrode layer has a thickness of 5nm to 1000nm.

In some embodiments, the electron transport layer comprises one or more of a metal oxide, a small organic molecule-based electron transport material, and a polymer-based electron transport material.

In some embodiments, the electron transport layer has a thickness of 1nm to 200nm.

In some of these embodiments, the thickness of the photovoltaic active layer is from 0.1 μm to 10 μm.

In some of these embodiments, the first silicon layer has a thickness of 5nm to 150nm.

In some embodiments, the N-type doped polysilicon layer is a polysilicon layer using phosphorus element and/or its same family element, the doping concentration is greater than 10 ¹⁸ cm^-3, and the thickness is 5-nm-150 nm.

In some of these embodiments, the second silicon layer has a thickness of 5nm to 150nm.

In some embodiments, the first P-type doped polysilicon layer is a polysilicon layer doped with boron element and/or its same family element, the doping concentration is greater than 10 ¹⁸ cm^-3, and the thickness is 5 nm-150 nm.

In some of these embodiments, the material of the second electrode layer includes a metal having conductive properties and an alloy thereof.

In some embodiments, the second electrode layer has a thickness of 5nm to 1000nm.

In some of these embodiments, the top solar cell further comprises a first anti-reflective layer, a first transparent conductive layer, and a hole transport layer disposed in a stack along the first direction;

the first anti-reflection layer and the first transparent conductive layer are sequentially stacked on the surface, close to the electron transmission layer, of the first electrode layer;

the hole transport layer is arranged on the surface, close to the first silicon layer, of the photovoltaic active layer in a layer-by-layer mode.

In some embodiments, the material of the first anti-reflection layer includes one or more of an inorganic compound and a polymer having a refractive index of 1.1 to 1.6 and an average transmittance of more than 99% at a wavelength of 200nm to 1200 nm.

In some of these embodiments, the first anti-reflective layer has a thickness of 10nm to 1000nm.

In some embodiments, the material of the first transparent conductive layer includes a metal oxide having a sheet resistance of less than 1000 Ω and an average transmittance of greater than 80% at a wavelength of 200nm to 1200 nm.

In some embodiments, the first transparent conductive layer has a thickness of 5nm to 1000nm.

In some embodiments, the hole transport layer material comprises one or more of a metal oxide, a small organic molecule-based hole transport material, and a polymer-based electron transport material.

In some of these embodiments, the hole transport layer has a thickness of 0.5nm to 200nm.

In some of these embodiments, the bottom solar cell further comprises a second transparent conductive layer or a second P-type doped polysilicon layer, a tunneling oxide layer or an intrinsic amorphous silicon layer, and a second anti-reflective layer, disposed in the first direction stack;

the second transparent conductive layer or the second P-type doped polycrystalline silicon layer is stacked on the surface, close to the photovoltaic active layer, of the first silicon layer along the first direction;

The tunneling oxide layer or the intrinsic amorphous silicon layer is stacked on the surface, far away from the photovoltaic active layer, of the first silicon layer along the first direction;

the second anti-reflection layer is stacked on the surface, far away from the crystal silicon substrate, of the second silicon layer along the first direction.

In some embodiments, the material of the second transparent conductive layer includes a metal oxide having a sheet resistance of less than 1000 Ω and an average transmittance of greater than 80% at a wavelength of 200nm to 1200 nm.

In some embodiments, the second transparent conductive layer has a thickness of 5nm to 1000nm.

In some embodiments, the second P-type doped polysilicon layer is a polysilicon layer doped with boron element and/or its same group element, the doping concentration is greater than 10 ¹⁸ cm^-3, and the thickness is 5 nm-150 nm.

In some embodiments, the intrinsic amorphous silicon layer is a hydrogen-containing amorphous silicon layer having a thickness of 1nm to 10nm.

In some embodiments, the tunneling oxide layer material includes one or both of silicon hydroxide-containing and silicon oxynitride-containing materials.

In some embodiments, the tunnel oxide layer has a thickness of 1nm to 2nm.

In some embodiments, the material of the second anti-reflection layer includes one or more of an inorganic compound and a polymer having a refractive index of 1.1 to 1.6 and an average transmittance of more than 99% at a wavelength of 200nm to 1200 nm.

In some of these embodiments, the second anti-reflective layer has a thickness of 10nm to 1000nm.

In some of these embodiments, the bottom solar cell further comprises a passivation layer;

The passivation layer is stacked on the surface of the second silicon layer, which is close to the second anti-reflection layer, along the first direction.

In some of these embodiments, the material of the passivation layer comprises an oxide of aluminum.

In some embodiments, the passivation layer has a thickness of 0.5nm to 500nm.

In a second aspect of the present invention, there is provided a method for manufacturing a laminated solar cell as described above, comprising the steps of:

The bottom solar cell and the top solar cell are stacked.

In some of these embodiments, the cross-sectional area S ₁ of the top solar cell along a second direction is less than the cross-sectional area S ₂ of the bottom solar cell, wherein the second direction is perpendicular to the first direction;

The preparation method of the laminated solar cell comprises the following steps:

and stacking a top solar cell in the bottom solar cell, and etching part of the top solar cell by a laser etching method to partially cover the surface of the bottom solar cell.

In a third aspect of the invention, a photovoltaic system is provided comprising a stacked solar cell as described above.

The invention has at least the following beneficial effects:

(1) Compared with a single cell, the energy gradient utilization of the laminated cell to sunlight can effectively reduce thermal relaxation energy loss, improve energy conversion efficiency and improve theoretical efficiency from 29.8% to 45.1%.

(2) The preferred area-mismatched laminated cell structure shown in the invention can further reduce the requirement on the band gap of the top cell and effectively expand the selection of the semiconductor compounds of the top cell. If the band gap of the top cell matched with the crystalline silicon cell is generally about 1.67eV, cdTe with the band gap of about 1.5eV can be effectively overlapped on the surface of the crystalline silicon cell by adopting the area mismatch mode in the invention, so that the energy conversion efficiency is improved. In addition, compared with a strategy of thinning the semiconductor film, the method can effectively avoid the problem of short circuit of the battery caused by exposure of the texture surface of the crystalline silicon battery due to the thinning of the active layer.

(3) The material for the photovoltaic active layer is an inorganic semiconductor material, is an element with rich crust content or a compound with good stability, has low cost and good sustainability, and is beneficial to large-scale application and popularization; and can effectually avoid ion migration, steam degradation scheduling problem under the multi-environment stress, can maintain outdoor long-term high-efficient photoelectric conversion ability, reduce photovoltaic technology's unit electricity generation cost.

Drawings

FIG. 1 is a schematic diagram of a stacked solar cell according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 3 is a top view of the stacked solar cell shown in FIG. 2;

FIG. 4 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 5 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 6 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 7 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 8 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 9 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 10 is a schematic diagram of a stacked solar cell according to an embodiment of the invention;

FIG. 11 is a schematic view of a stacked solar cell according to an embodiment of the present invention;

Fig. 12 is a schematic structural view of a stacked solar cell according to comparative example 1 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Where the terms "comprising," "having," and "including" are used herein, it is intended to cover a non-exclusive inclusion, another element may be added, unless a specifically defined term is used, such as "consisting of … …," etc.

In the present invention, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", and "a third" may explicitly or implicitly include at least one such feature.

In the present invention, directional terms such as "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate that the direction and positional relationship are based on that shown in the drawings, are merely for convenience of description and to simplify the description, and do not indicate or imply that the apparatus or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present invention.

In describing positional relationships, when an element such as a layer, film or substrate is referred to as being "on" another film layer, it can be directly on the other film layer or intervening film layers may also be present, unless otherwise indicated. Further, when a layer is referred to as being "under" another layer, it can be directly under, or one or more intervening layers may also be present. It will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

The words "preferably," "more preferably," "more preferably," and the like, refer to embodiments of the invention that may provide certain benefits in some instances. However, other embodiments may be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention. That is, in the present invention, "preferable", "more preferable", etc. are merely description of embodiments or examples that are more effective, but do not limit the scope of the present invention.

In the present invention, "further", "still further", "particularly" and the like are used for descriptive purposes to indicate differences in content but should not be construed as limiting the scope of the invention.

In the present invention, "at least one" means one or more, such as one, two or more. The meaning of "plural" or "several" means at least two, for example, two, three, etc., and the meaning of "multiple" means at least two, for example, two, three, etc., unless specifically defined otherwise. In the description of the present invention, the meaning of "several" means at least one, such as one, two, etc., unless specifically defined otherwise.

When a range of values is disclosed in the present invention, the range is considered to be continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range description features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to include any and all subranges subsumed therein. And only a few numerical ranges are specifically disclosed herein. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each separately disclosed point or individual value may itself be combined as a lower limit or upper limit with any other point or individual value or with other lower limit or upper limit to form a range not explicitly recited.

All steps of the present invention may be performed sequentially or randomly unless otherwise specified. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, or may comprise steps (b) and (a) performed sequentially. For example, the method may further comprise step (c), meaning that step (c) may be added to the method in any order, e.g., the method may comprise steps (a), (b) and (c), steps (a), (c) and (b), steps (c), (a) and (b), etc.

Unless mentioned to the contrary, singular terms may include plural and are not to be construed as being one in number.

The temperature parameter in the present invention is not particularly limited, and may be a constant temperature treatment or a treatment within a predetermined temperature range. The constant temperature process allows the temperature to fluctuate within the accuracy of the instrument control.

The weights of the relevant components mentioned in the embodiments of the present invention may refer not only to the specific contents of the respective components but also to the proportional relationship between the weights of the respective components, and thus, it is within the scope of the disclosure of the embodiments of the present invention as long as the contents of the relevant components are scaled up or down according to the embodiments of the present invention. Specifically, the weight described in the examples of the present invention may be mass units known in the chemical industry such as mu g, mg, g, kg.

In the present invention, referring to a unit of a data range, if a unit is only carried behind a right end point, the units indicating the left and right end points are the same. For example, 800-850 nm indicates that the units of the left end point "800" and the right end point "850" are nm (nanometers).

In the present invention, "above" or "below" includes the present number, such as 1 or below, indicating 1 or less (1 or less), 1 or above, indicating 1 or more (1 or more).

In the present invention, "a and B are independently selected from x, y or z" means that a and B are independent events, and event a does not affect occurrence of event B, so that B may be selected from any one of x, y or z when a is selected from x, B may be selected from any one of x, y or z when a is selected from y, and B may be selected from any one of x, y or z when a is selected from z.

In the present invention, the top solar cell may be abbreviated as a top cell or a front cell, and the bottom solar cell may be abbreviated as a bottom cell or a rear cell.

In the present invention, the first direction coincides with the thickness direction of the stacked solar cell.

Although the perovskite-crystalline silicon laminated battery is efficient, the stability is poor, and the accumulated power generation amount is not superior to that of a single battery; the III-V group and crystalline silicon laminated battery has high efficiency and stability, but extremely high price limits the application.

The technical proposal is as follows:

referring to fig. 1 and 2, an embodiment of the present invention provides a laminated solar cell 1 including a top solar cell 10 and a bottom solar cell 20 laminated in a first direction (thickness direction);

The cross-sectional area S ₁ of the top solar cell 10 along a second direction is less than or equal to the cross-sectional area S ₂ of the bottom solar cell 20, wherein the second direction is perpendicular to the first direction;

the bandgap of the top solar cell 10 is wider than the bandgap of the bottom solar cell 20;

the top solar cell 10 includes a photovoltaic active layer whose material is an inorganic semiconductor material.

It will be appreciated that in the present invention, the bottom solar cell 20 and the top solar cell 10 are in a series relationship.

In some of these embodiments, as shown in fig. 1, the cross-sectional area S ₂ of the bottom solar cell 20 along the second direction is equal to the cross-sectional area S ₁ of the top solar cell 10.

In some of these embodiments, as shown in fig. 2, the cross-sectional area S ₂ of the bottom solar cell 20 along the second direction is greater than the cross-sectional area S ₁ of the top solar cell 10.

In some of these embodiments, at am1.5g, the short circuit current density of the top solar cell 10 is a and the short circuit current density of the bottom solar cell 20 is b;

S ₁、S₂, a and b satisfy:

b≤2a＜2b，S₂=（2a/b）*S₁；

Wherein a and b are in units of mA/cm ²,S₁ and S ₂ are in units of cm ².

Fig. 3 is a top view of the stacked solar cell structure shown in fig. 2, wherein the areas of the top and bottom cells are not equal, the orange area is the top solar cell, the blue area is the bare bottom solar cell, the black area is the grid line area of the cell, the number of grid lines contained in a in fig. 3 is less, and the number of grid lines contained in B in fig. 3 is more.

It will be appreciated that the stacked solar cells 1 shown in fig. 1 to 3 are each a series structure in which a top cell and a bottom cell are directly combined.

In some of these embodiments, the stacked solar cell is a tandem structure having a tunneling composite, and as shown in fig. 4, the stacked solar cell 1 includes a top solar cell 10, a first tunneling composite 30, a second tunneling composite 40, and a bottom solar cell 20 stacked in a first direction (thickness direction). Further, the materials of the first tunneling composite layer 30 and the second tunneling composite layer 40 each independently include one or more of N-type heavily doped amorphous silicon (or N-type heavily doped microcrystalline silicon), P-type heavily doped amorphous silicon (or P-type heavily doped microcrystalline silicon), transparent conductive oxide, nickel oxide, tin oxide, and molybdenum oxide.

For convenience of description, the following describes the battery structure and the functional layers thereof in detail with reference to the accompanying drawings, and the details are as follows:

In some embodiments, as shown in fig. 5, the top solar cell 10 includes a first electrode layer 110, an electron transport layer 120, and a photovoltaic active layer 130 sequentially stacked along the first direction, wherein the photovoltaic active layer 130 is closest to the bottom solar cell 20, and the first electrode layer 110 is furthest from the bottom solar cell 20;

The bottom solar cell 20 includes a first silicon layer 210, a crystalline silicon substrate 220, a second silicon layer 230, and a second electrode layer 240 sequentially stacked along the first direction, wherein the first silicon layer 210 is closest to the top solar cell 10, and the second electrode layer 240 is farthest from the top solar cell 10;

the first silicon layer 210 is an N-type doped polysilicon layer, an N-type doped microcrystalline silicon layer, or a first amorphous silicon layer;

The second silicon layer 230 is a first P-type doped polysilicon layer, a P-type doped microcrystalline silicon layer, a second amorphous silicon layer, or a P-type diffusion layer.

1. Regarding the top solar cell:

in some embodiments, the material of the first electrode layer 110 includes a metal having conductive properties and an alloy thereof, and the material of the first electrode layer 110 includes, without limitation, one or more of silver, copper, gold, aluminum, tin, titanium, a silver-containing compound, a copper-containing compound, a gold-containing compound, an aluminum-containing compound, a tin-containing compound, and a titanium-containing compound.

In some embodiments, the first electrode layer 110 has a thickness of 5nm to 1000nm.

In some embodiments, the material of the electron transport layer 120 includes one or more of a metal oxide, a small organic molecule-based electron transport material, and a polymer-based electron transport material. Optionally, the material of the electron transport layer 120 includes one or more of perylene diimide compounds, naphthalimide compounds, fullerenes and derivatives thereof, and high molecular compounds (PFN-Br, N2200, which are typical electron transport materials).

In some embodiments, the electron transport layer 120 has a thickness of 1nm to 200nm.

In the present invention, the material of the photovoltaic active layer 130 is an inorganic semiconductor material.

Formula (1): a1 _x1B1_(1-x1)C1_y1D1_(1-y1);

Formula (2): A2A 2 _x2B2_(1-x2)C2_y2D2_(1-y2)E_2zF_2(1-z)

Formula (3): sb ₂S_3x3Se_3(1-x3);

The C1 position is selected from one or more of O ^2-、S^2- and Se ^2-;

0≤x1<1，0≤y1<1，0≤x2<1，0≤y2<1，0≤z<1，0≤x3≤1。

the above listed compounds are stoichiometric ratios in the ideal case, and compounds that deviate from the stoichiometric ratios are within the scope of the present invention as long as they are recognized in the art.

For convenience of description, the covalent compound semiconductor materials represented by the general formulae (1), (2) and (3) will be described separately, concretely as follows:

1. with respect to formula (1): a1 _x1B1_(1-x1)C1_y1D1_(1-y1):

Wherein the A1 position is selected from one or more of Zn ²⁺、Mg²⁺、Mn²⁺、Ca²⁺、Ba²⁺ and Cu ²⁺, and the A1 position is preferably selected from one or more of Zn ²⁺ and Mg ²⁺;

The B1 position is selected from one or more of Zn ²⁺、Mg²⁺、Mn²⁺、Ca²⁺、Ba²⁺、Cu²⁺ and Cd ²⁺, and the B1 position is preferably Cd ²⁺;

The C1 position is selected from one or more of O ^2-、S^2- and Se ^2-, and the C1 position is preferably selected from one or more of S ^2- and Se ^2-;

The D1 position is selected from one or more of O ^2-、S^2-、Se^2- and Te ^2-, and the D1 position is Te ^2- preferably;

0≤x1<1，0≤y1<1。

preferably, formula (1): a1 _x1B1_(1-x1)C1_y1D1_(1-y1) is selected from one or more of Zn _x1Cd_(1-x1)Te、Mg_x1Cd_(1-x1)Te、Mn_x1Cd_(1-x1) Te and CdTe, with CdTe being most preferred.

2. With respect to formula (2): a2 _x2B2_(1-x2)C2_y2D2_(1-y2)E_2zF_2(1-z):

Wherein the A2 position is selected from one or more of Ag ⁺、Au⁺、Cs⁺ and Rb ⁺, and the A2 position is preferably Ag ⁺;

The B2 position is selected from one or more of Ag ⁺、Au⁺、Cs⁺、Rb⁺ and Cu ⁺, and the B2 position is preferably Cu ⁺;

The C2 position is selected from one or more of Fe ³⁺、Cr³⁺、Co³⁺、Al³⁺、In³⁺ and Ga ³⁺, and the C2 position is preferably selected from one or more of Al ³⁺ and In ³⁺;

The D2 position is selected from one or more of Fe ³⁺、Cr³⁺、Co³⁺、Al³⁺、In³⁺ and Ga ³⁺, and the D2 position is preferably Ga ³⁺;

The E position and the F position are respectively and independently selected from one or more of O ^2-、S^2-、Se^2- and Te ^2-, the E position is preferably selected from one or more of O ^2- and S ^2-, and the F position is preferably selected from Se ^2-;

0≤x2<1，0≤y2<1，0≤z<1。

Preferably, formula (2): a2 _x2B2_(1-x2)C2_y2D2_(1-y2)E_2zF_2(1-z) is selected from one or more of AgInS₂、CuInS₂、CuIn_yGa_1-yS₂、CuIn_yGa_1-ySe₂、CuGaSe₂ and AgGaSe ₂, preferably CuIn _yGa_1-yS₂.

3. With respect to formula (3): sb ₂S_3x3Se_3(1-x3):

Wherein x3 is more than or equal to 0 and less than or equal to 1, and preferably x3 is more than or equal to 0 and less than or equal to 0.1.

Preferably, in the laminated solar cell in some examples of the present invention, the top cell/front cell avoids using an ionic semiconductor, an inorganic (simple substance or covalent compound) semiconductor such as CdTe, CIGS, sb ₂S₃ is adopted, the bottom cell/rear cell adopts a stable crystalline silicon cell, and has excellent photovoltaic properties and stability.

In some of these embodiments, as shown in fig. 6, the top solar cell 10 further includes a first anti-reflection layer 140, a first transparent conductive layer 150, and a hole transport layer 160 stacked along the first direction;

The first anti-reflection layer 140 and the first transparent conductive layer 150 are sequentially stacked on the surface of the first electrode layer 110, which is close to the electron transport layer 120;

The hole transport layer 160 is stacked on the surface of the photovoltaic active layer 130 near the first silicon layer 210 (preferably, an N-doped layer).

In some embodiments, the material of the first anti-reflection layer 140 includes one or more of inorganic compounds and polymers having a refractive index of 1.1 to 1.6 and an average transmittance of more than 99% at a wavelength of 200nm to 1200nm, such as LiF, mgFx, silicon nitride, silicon oxide, silicon oxynitride, and the like, and polymer materials, such as Polydimethylsiloxane (PDMS) and/or polyurethane.

In some embodiments, the thickness of the first anti-reflection layer 140 is 10nm to 1000nm.

In some embodiments, the material of the first transparent conductive layer 150 includes a metal oxide having a sheet resistance of less than 1000Ω and an average transmittance of more than 80% at a wavelength of 200nm to 1200nm, such as one or more of indium tin oxide, aluminum zinc oxide, aluminum indium oxide, indium cerium oxide, and indium tungsten oxide.

In some embodiments, the thickness of the first transparent conductive layer 150 is 5nm to 1000nm a.

In some embodiments, the hole transport layer 160 is made of a compound with hole selective transport and electron blocking effects, including one or more of metal oxides, organic small molecule hole transport materials and polymer electron transport materials. Further, the material of the hole transport layer includes one or more of inorganic compounds (such as MoO _x、NiO_x、Cu₂ O, cuSCN, etc.), organic compounds (Spiro), and high molecular compounds (such as PM6, PDBD-T).

In some embodiments, the hole transport layer 160 has a thickness of 0.5nm to 200nm.

2. Regarding the bottom solar cell:

It will be appreciated that in the present invention, the bottom cell may be in either a TOPCON configuration or HJT configuration, without limitation.

In some embodiments, the thickness of the first silicon layer 210 is 5nm to 150nm.

In some embodiments, the first silicon layer 210 is an N-doped polysilicon layer. Further, the N-type doped polysilicon layer is a polysilicon layer using phosphorus element and/or its same family element, the doping concentration is more than 10 ¹⁸ cm^-3, and the thickness is 5 nm-150 nm.

It is to be understood that the present invention is not particularly limited as to the type of the crystalline silicon substrate 220, and either an N-type silicon substrate or a P-type silicon substrate may be used.

The second silicon layer 230 is a first P-type doped polysilicon layer. Further, the first P-type doped polysilicon layer is a polysilicon layer doped by boron element and/or the same group element thereof, the doping concentration is more than 10 ¹⁸ cm^-3, and the thickness is 5 nm-150 nm.

In some embodiments, the material of the second electrode layer 240 includes a metal having conductive properties and an alloy thereof, and the material of the second electrode layer 240 includes, without limitation, one or more of silver, copper, gold, aluminum, tin, titanium, a silver-containing compound, a copper-containing compound, a gold-containing compound, an aluminum-containing compound, a tin-containing compound, and a titanium-containing compound.

In some embodiments, the second electrode layer 240 has a thickness of 5nm to 1000nm.

In some embodiments, as shown in fig. 7, the bottom solar cell 20 further includes a second transparent conductive layer 2501 or a second P-type doped polysilicon layer 2502, a tunneling oxide layer 2601 or an intrinsic amorphous silicon layer 2602, and a second anti-reflection layer 270 stacked along the first direction;

The second transparent conductive layer 2501 or the second P-type doped polysilicon layer 2502 is stacked on the surface of the first silicon layer 210 near the photovoltaic active layer 130 along the first direction;

the tunnel oxide layer 2601 or the intrinsic amorphous silicon layer 2602 is stacked on the surface of the first silicon layer 210 away from the photovoltaic active layer 130 along the first direction;

the second anti-reflection layer 270 is stacked on the surface of the second silicon layer 230 away from the crystalline silicon substrate 220 along the first direction.

In some embodiments, the material of the second transparent conductive layer 2501 comprises a metal oxide having a sheet resistance of less than 1000 Ω and an average transmittance of greater than 80% at a wavelength of 200nm to 1200nm, such as one or more of indium tin oxide, aluminum zinc oxide, aluminum indium oxide, indium cerium oxide, and indium tungsten oxide.

In some embodiments, the second transparent conductive layer 2501 has a thickness of 5nm to 1000nm.

In some embodiments, the second P-type doped polysilicon layer 2502 is a polysilicon layer doped with boron and/or its same family element, and has a doping concentration of greater than 10 ¹⁸ cm^-3 and a thickness of 5: 5 nm-150: 150 nm.

In some of these embodiments, the material of the tunnel oxide layer 2601 includes one or both of silicon hydroxide and silicon oxynitride.

In some embodiments, the tunnel oxide layer 2601 has a thickness of 1nm to 2nm.

In some of these embodiments, the intrinsic amorphous silicon layer 2602 is a hydrogen-containing amorphous silicon layer having a thickness of 1nm to 10nm.

In some embodiments, the material of the second anti-reflection layer 270 includes one or more of inorganic compounds and polymers having a refractive index of 1.1 to 1.6 and an average transmittance of more than 99% at a wavelength of 200nm to 1200nm, such as LiF, mgFx, silicon nitride, silicon oxide, silicon oxynitride, and the like, and polymer materials, such as PDMS, polyurethane, and the like.

In some embodiments, the second anti-reflective layer 270 has a thickness of 10nm to 1000nm.

In some of these embodiments, as shown in fig. 8, the bottom solar cell 20 further includes a passivation layer 280;

The passivation layer 280 is stacked along the first direction on the surface of the second silicon layer 230 near the second anti-reflection layer 270.

In some of these embodiments, the material of the passivation layer 280 includes an oxide of aluminum.

In some embodiments, the passivation layer 280 has a thickness of 0.5nm to 500nm.

As can be appreciated, referring to fig. 9 and 10, in some embodiments, the top cell further includes a window layer 170 disposed in a stack along the first direction. Further, the material of the window layer 170 is MgZnO. Further, the thickness of the window layer 170 is 1nm to 200nm.

Referring to fig. 10 and 11, in some embodiments, a second tunnel oxide layer 290 is further laminated between the N-type crystalline silicon substrate and the P-type doped polysilicon layer, consistent with the description of tunnel oxide layer 2601 above.

In some embodiments, along the first direction, the stacked solar cell (fig. 9) includes a first metal electrode layer, a MgFx anti-reflection layer, an ITO conductive layer, a MgZnO window layer, an electron transport layer, a photovoltaic active layer, a hole transport layer, a transparent conductive layer, an N-doped polysilicon layer, a tunneling oxide layer, an N-type crystalline silicon substrate, a P-type diffusion region, an Al ₂O_x passivation layer, a silicon nitride and/or silicon oxynitride anti-reflection layer, and a second metal electrode layer, which are stacked in this order.

In some embodiments, the stacked solar cell (fig. 10) includes a first metal electrode layer, a MgFx anti-reflection layer, an ITO conductive layer, a MgZnO window layer, an electron transport layer, a photovoltaic active layer, a hole transport layer, a transparent conductive layer, an N-type doped polysilicon layer, a first tunneling oxide layer (i.e., the aforementioned tunneling oxide layer 2601), an N-type crystalline silicon substrate, a second tunneling oxide layer, a P-type doped polysilicon layer, a silicon nitride and/or silicon oxynitride anti-reflection layer, and a second metal electrode layer, which are stacked in this order.

The invention also provides a preparation method of the laminated solar cell, which comprises the following steps:

The bottom solar cell and the top solar cell are stacked.

The invention also provides a photovoltaic system (not shown) comprising a stacked solar cell as described above.

The photovoltaic system can be applied to a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station and the like, and can also be applied to equipment or devices for generating power by utilizing solar energy, such as a user solar power supply, a solar street lamp, a solar automobile, a solar building and the like. Of course, it is understood that the application scenario of the photovoltaic system is not limited thereto, that is, the photovoltaic system may be applied to all fields where solar energy is required to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system can comprise a photovoltaic array, a confluence box and an inverter, wherein the photovoltaic array can be an array combination of a plurality of photovoltaic modules, for example, the photovoltaic modules can form a plurality of photovoltaic arrays, the photovoltaic arrays are connected with the confluence box, the confluence box can confluence currents generated by the photovoltaic arrays, and the confluence currents flow through the inverter to be converted into alternating currents required by a commercial power grid and then are connected with the commercial power network so as to realize solar power supply.

The invention will be described in connection with the following examples, but it is not limited thereto, and it is to be understood that the appended claims summarize the scope of the invention and that certain changes made to the various embodiments of the invention which are contemplated by one skilled in the art are to be covered by the spirit and scope of the appended claims.

In a specific embodiment the top solar cell is abbreviated as top cell and the bottom solar cell is abbreviated as bottom cell.

Example 1

The embodiment provides a laminated solar cell shown in fig. 9 and a preparation method thereof, wherein CdTe is selected as a photovoltaic active layer material of a top cell, and the specific preparation process of the laminated solar cell is as follows:

(1) Preparing a bottom battery:

① And (3) wool making: selecting an N-type silicon wafer with minority carrier lifetime longer than 10ms, placing the N-type silicon wafer in a solution containing KOH and a texturing additive for double-sided texturing, forming pyramid texture on the surface of the silicon wafer, and controlling the size of the pyramid texture to be about 2 mu m;

② Diffusion: b diffusion is adopted for preparing an emitter on the front surface of a silicon wafer, a boron diffusion source adopts BCl ₃, the diffusion temperature is 1000 ℃, and the thickness of silicon oxide formed by boron diffusion is controlled to be 80nm;

③ Cleaning and polishing: firstly, cleaning back silicon oxide by using acid, and then polishing by using alkali liquor to obtain a silicon wafer structure with a planar back surface;

④ Oxidation and polysilicon deposition: in PECVD equipment, siO ₂ oxidation deposition with the thickness of 1 nm-2 nm is completed, and then an N-type polycrystalline silicon layer with the thickness of 50nm (the doping element is phosphorus) is deposited, wherein the doping concentration is more than 10 ¹⁸ cm^-3;

⑤ Front cleaning: removing the polysilicon layer which is wound and plated on the front surface by using alkali washing, removing silicon oxide formed by front surface boron diffusion by using acid washing, and then washing and drying;

⑥ Front passivation: depositing a 100nm thick passivation layer of aluminum oxide using an ALD apparatus;

⑦ Front and back antireflection: depositing 100nm thick silicon nitride by using a PECVD device;

⑧ Front side metallization: preparing a metal electrode on the front surface of the battery by using screen printing silver paste, wherein the thickness of the dried metal electrode is controlled to be 20 mu m, and the width of the metal electrode is controlled to be 30 mu m;

⑨ Back side antireflection removal: removing the silicon nitride anti-reflection layer on the back of the silicon wafer by using acid washing;

(2) Preparing a top battery:

① Preparing a transparent electrode: manufacturing an ITO film layer with the thickness of 10nm on the back surface of the top battery by using a magnetron sputtering process to serve as a composite layer;

② Hole transport layer preparation: depositing a NiO _x hole transport layer with the thickness of 10nm on the ITO film layer by using a magnetron sputtering device;

③ Preparation of CdTe layer: depositing a CdTe film layer with the thickness of 3 mu m by using a near space sublimation method at the temperature of 500-700 ℃, and then treating the CdTe film layer in a CdCl ₂ moisture atmosphere to finish the preparation of the photovoltaic active layer;

④ Preparing a CdS layer: using a magnetron sputtering method to manufacture a CdS film layer with the thickness of 80nm under the condition of introducing oxygen;

⑤ Window layer manufacturing: using ALD equipment to manufacture a MgZnO window layer with the thickness of 20 nm;

⑥ And (3) manufacturing a top transparent electrode: manufacturing an ITO film layer with the thickness of 100nm on the back surface of the top battery by using a magnetron sputtering process, and taking the ITO film layer as a conductive electrode;

⑦ Top metal electrode: preparing a metal electrode by using screen printing silver paste, wherein the thickness after drying is controlled to be 20 mu m, and the width is controlled to be 30 mu m;

⑧ Antireflection preparation: using a thermal vapor deposition method, 100nm MgFx was produced as an antireflection film.

Example 2

The embodiment provides a laminated solar cell shown in fig. 9 and a preparation method thereof, wherein CuGaSe ₂ is selected as a photovoltaic active layer material of a top cell, and the specific preparation process of the laminated solar cell is as follows:

(1) Preparing a bottom battery: the bottom cell was made the same as in example 1;

(2) Preparing a top battery:

① The transparent electrode was in accordance with example 1;

② Hole transport layer: evaporating 1nm metal molybdenum as a hole transport layer by using a thermal evaporation mode;

⑨CuGaSe₂ Layer (c): using a CuGaSe ₂ alloy target material and using magnetron sputtering to manufacture a CuGaSe ₂ film with the thickness of 3 mu m so as to finish manufacturing a photovoltaic active layer;

⑦ Top metal electrode: a metal electrode was prepared using screen printing, as in example 1;

Example 3

The embodiment provides a laminated solar cell shown in fig. 9 and a preparation method thereof, wherein Sb ₂S₃ is selected as a photovoltaic active layer material of a top cell, and the specific preparation process of the laminated solar cell is as follows:

(2) Preparing a top battery:

① The transparent electrode was in accordance with example 1;

③Sb₂S₃ Layer (c): using Sb ₂S₃ precursor solution, controlling the thickness of the active layer to be 800 nm through a spin coating process, and then annealing at 200 ℃ to finish the preparation of the photovoltaic active layer;

④ And (3) preparing an electron transport layer: depositing a 10 nm-thick SnO ₂ electron transport layer on the film layer by using an ALD (atomic layer deposition) device;

⑤ And (3) manufacturing a top transparent electrode: manufacturing an ITO film layer with the thickness of 100nm on the back surface of the top battery by using a magnetron sputtering process, and taking the ITO film layer as a conductive electrode;

⑥ Top metal electrode: a metal electrode was prepared using screen printing, as in example 1;

⑦ Antireflection preparation: using a thermal vapor deposition method, 100nm MgFx was produced as an antireflection film.

Example 4

The embodiment provides a laminated solar cell shown in fig. 10 and a preparation method thereof, wherein CuGaSe ₂ is selected as a photovoltaic active layer material of a top cell, and the specific preparation process of the laminated solar cell is as follows:

(1) Preparing a bottom battery:

① And (3) wool making: selecting an N-type silicon wafer with minority carrier lifetime longer than 10ms, placing the N-type silicon wafer in a solution containing KOH and a texturing additive for double-sided texturing, forming pyramid texture on the surface of the silicon wafer, and controlling the size of the pyramid texture to be 2 mu m; oxidizing: thermally oxidizing the surface of the silicon wafer, and depositing SiO ₂ with the thickness of 2 nm;

② And (3) depositing a polysilicon layer: respectively depositing p-type amorphous silicon on the front side and n-type amorphous silicon on the back side of the silicon wafer by PECVD, and carrying out heating annealing crystallization to manufacture a doped polycrystalline silicon layer;

③ Front and back antireflection: depositing 100nm thick silicon nitride by using a PECVD device;

④ Front side metallization: preparing a metal electrode on the front surface of the battery by screen printing;

⑤ Back side antireflection removal: removing the silicon nitride anti-reflection layer on the back of the silicon wafer by using acid washing;

(2) Preparing a top battery:

The top cell was prepared in the same manner as in example 2.

Example 5

This example provides a stacked solar cell as shown in fig. 10 and a method of making the same, substantially as in example 4, except that the anti-reflective layer on the top cell is removed.

Example 6

This example provides a stacked solar cell and method of making the same as that of example 4, except that the hole transport layer was removed during the top cell fabrication process.

Example 7

The embodiment provides a laminated solar cell shown in fig. 11 and a preparation method thereof, which are consistent with embodiment 4, and the area of the active area of the top cell is etched to be 89.1% of the initial area by using laser etching before carrying out ⑧ MgFx antireflection film layer preparation, and then the antireflection layer coating is carried out;

in this example, a is 23 mA/cm ², b is 41 mA/cm ²,S₂, 220.5 cm ²,S₁ is 196.5 cm ².

Comparative example 1

This comparative example provides a laminated solar cell and a method for producing the same shown in fig. 12, in which perovskite cell 50 is used as a top cell, crystalline silicon cell 60 (same as in example 4) is used as a bottom cell, wherein 510 represents a first metal electrode, 520 represents an MgF antireflection layer, 530 represents an ITO conductive layer, 540 represents a tin dioxide electron transport layer, 550 represents a C60 electron transport layer, 560 represents a perovskite active layer, 570 represents a hole transport layer, 610 represents a transparent conductive layer, 620 represents an N-type doped polysilicon layer, 630 represents a first tunneling oxide layer, 640 represents an N-type crystalline silicon substrate, 650 represents a second tunneling oxide layer, 660 represents a P-type doped polysilicon layer, 670 represents a silicon nitride antireflection layer, 680 represents a second metal electrode, and the method for producing the laminated solar cell is specifically as follows:

(1) Preparing a bottom battery: the bottom cell was made the same as in example 4;

(2) Preparing a top battery:

① Manufacturing a hole transport layer NiO _x with the thickness of 10nm on a bottom cell;

② A solution process was then used to deposit a 0.8 um a thick perovskite active layer (FA _0.75Cs_0.25PbI_2.25Br_0.75);

③ Then depositing 20nm C ₆₀ as a first electron transport layer by using a thermal evaporation mode;

④ Depositing 20nm SnO ₂ as a second electron transport layer by using an atomic layer deposition mode;

⑤ Then, manufacturing an ITO film layer with the thickness of 100nm on the electron transmission layer by using magnetron sputtering as a conductive electrode;

The stacked solar cells of device examples 1 to 7 and device comparative example 1 were subjected to performance test as follows:

(1) Efficiency test:

And placing the device to be tested in an environment at 25 ℃ for 24 hours, and testing after the temperature of the device to be tested is stable. Setting the irradiation power of the device to be tested to be 1000W m ^-2 by using a 3A-level solar simulator, then placing the device to be tested under the solar simulator, testing the device to be tested by using an I-V tester to obtain a volt-case characteristic curve, and obtaining the photoelectric conversion efficiency of the battery to be tested under AM1.5G through calculation.

(2) T80 test: the AM1.5G is used for simulating the spectrum of the xenon lamp, the battery is continuously tracked at the maximum power point, the time for the battery efficiency to decay to 80% is used, if the stability of the battery is relatively good, the decay rate of 1000 hours can be tested, and the time for the battery to decay to 80% is calculated by using an extrapolation method.

The test results are shown in Table 1.

TABLE 1

As can be seen from table 1, compared with the device comparative example 1, the perovskite material is adopted as the photovoltaic active layer of the top cell, the photovoltaic active layer of the top cell is made of the inorganic semiconductor material in the device examples 1 to 7, the open-circuit voltage, the short-circuit current density, the filling factor and the photoelectric conversion efficiency of the laminated solar cell are equivalent in cooperation with the crystalline silicon bottom cell, the service life is greatly increased, and the laminated solar cell of the device examples 1 to 7 fully has the advantages of high stability and high photoelectric conversion efficiency. Further, in each device embodiment, the cross-sectional area S ₁ of the device embodiment 7 of the control top cell is smaller than the cross-sectional area S ₂ of the bottom cell, and the open-circuit voltage, the short-circuit current density, the filling factor, the photoelectric conversion efficiency and the service life of the stacked solar cell are all higher, which indicates that the stacked solar cell has excellent photovoltaic property and stability.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present invention and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A laminated solar cell comprising a top solar cell and a bottom solar cell laminated in a first direction;

the top solar cell has a wider bandgap than the bottom solar cell;

2. The stacked solar cell of claim 1, wherein at am1.5g, the top solar cell has a short circuit current density of a and the bottom solar cell has a short circuit current density of b;

S ₁、S₂, a and b satisfy:

b≤2a＜2b，S₂=（2a/b）*S₁；

Wherein a and b are in units of mA/cm ²,S₁ and S ₂ are in units of cm ².

3. The laminated solar cell according to claim 1, wherein the inorganic semiconductor material has a band gap of 1.2eV to 1.8eV.

4. The tandem solar cell according to claim 1, wherein said inorganic semiconductor material is selected from Se, te, ge and one or more of the following formulas (1) to (3):

Formula (1): a1 _x1B1_(1-x1)C1_y1D1_(1-y1);

Formula (2): A2A 2 _x2B2_(1-x2)C2_y2D2_(1-y2)E_2zF_2(1-z)

Formula (3): sb ₂S_3x3Se_3(1-x3);

The C1 position is selected from one or more of O ^2-、S^2- and Se ^2-;

0≤x1<1，0≤y1<1，0≤x2<1，0≤y2<1，0≤z<1，0≤x3≤1。

5. The tandem solar cell of claim 4, wherein said inorganic semiconductor material comprises one or more of Zn_x1Cd_(1-x1)Te、Mg_x1Cd_(1-x1)Te、Mn_x1Cd_(1-x1)Te、CdTe、AgInS₂、CuInS₂、CuIn_yGa_1-yS₂、CuIn_yGa_1- _ySe₂、CuGaSe₂、AgGaSe₂ and Sb ₂S_3x3Se_3(1-x3).

6. The laminated solar cell according to any one of claims 1 to 5, wherein the top solar cell comprises a first electrode layer, an electron transport layer and a photovoltaic active layer arranged in sequence along the first direction, wherein the photovoltaic active layer is closest to the bottom solar cell and the first electrode layer is furthest from the bottom solar cell;

7. The laminated solar cell according to claim 6, wherein one or more of the following (1) to (9) are satisfied:

(1) The material of the first electrode layer includes a metal having conductive properties and an alloy thereof;

(2) The thickness of the first electrode layer is 5 nm-1000 nm;

(3) The material of the electron transport layer comprises one or more of metal oxide, organic micromolecular electron transport material and polymer electron transport material;

(4) The thickness of the electron transport layer is 1 nm-200 nm;

(5) The thickness of the photovoltaic active layer is 0.1-10 mu m;

(6) The thickness of the first silicon layer is 5 nm-150 nm;

(7) The N-type doped polysilicon layer is a polysilicon layer using phosphorus element and/or the same group element thereof, the doping concentration is more than 10 ¹⁸ cm^-3, and the thickness is 5 nm-150 nm;

(8) The thickness of the second silicon layer is 5 nm-150 nm;

(9) The first P-type doped polysilicon layer is a polysilicon layer doped by boron element and/or the same group element thereof, the doping concentration is more than 10 ¹⁸ cm^-3, and the thickness is 5-150 nm;

(10) The material of the second electrode layer comprises a metal with conductive property and an alloy thereof;

(11) The thickness of the second electrode layer is 5 nm-1000 nm.

8. The stacked solar cell of claim 6, wherein the top solar cell further comprises a first anti-reflective layer, a first transparent conductive layer, and a hole transport layer stacked along the first direction;

9. The laminated solar cell according to claim 8, wherein one or more of the following (1) to (8) are satisfied:

(1) The material of the first anti-reflection layer comprises one or more of inorganic compounds and polymers, wherein the refractive index of the inorganic compounds is 1.1-1.6, and the average transmittance of the inorganic compounds is more than 99% under the condition of the wavelength of 200-1200 nm;

(2) The thickness of the first anti-reflection layer is 10 nm-1000 nm;

(3) The material of the first transparent conductive layer comprises metal oxide with sheet resistance smaller than 1000 omega and average transmittance larger than 80% under the condition of wavelength of 200 nm-1200 nm;

(4) The thickness of the first transparent conductive layer is 5 nm-1000 nm;

(5) The material of the hole transport layer comprises one or more of metal oxide, organic micromolecular hole transport material and polymer electron transport material;

(6) The thickness of the hole transport layer is 0.5 nm-200 nm.

10. The stacked solar cell of claim 6, wherein the bottom solar cell further comprises a second transparent conductive layer or a second P-doped polysilicon layer, a tunnel oxide layer or an intrinsic amorphous silicon layer, and a second anti-reflective layer stacked along the first direction;

11. The laminated solar cell according to claim 10, wherein one or more of the following (1) to (8) are satisfied:

(1) The material of the second transparent conductive layer comprises metal oxide with sheet resistance smaller than 1000 omega and average transmittance larger than 80% under the condition of wavelength of 200 nm-1200 nm;

(2) The thickness of the second transparent conductive layer is 5 nm-1000 nm;

(3) The second P-type doped polysilicon layer is a polysilicon layer doped by boron element and/or the same group element thereof, the doping concentration is more than 10 ¹⁸ cm^-3, and the thickness is 5-150 nm;

(4) The intrinsic amorphous silicon layer is a hydrogen-containing amorphous silicon layer, and the thickness is 1 nm-10 nm;

(5) The tunneling oxide layer comprises one or two of silicon hydroxide and silicon oxynitride;

(6) The thickness of the tunneling oxide layer is 1 nm-2 nm;

(7) The material of the second anti-reflection layer comprises one or more of inorganic compounds and polymers, wherein the refractive index of the inorganic compounds is 1.1-1.6, and the average transmittance of the inorganic compounds is more than 99% under the condition of the wavelength of 200-1200 nm;

(8) The thickness of the second anti-reflection layer is 10 nm-1000 nm.

12. The laminated solar cell of claim 10, wherein the bottom solar cell further comprises a passivation layer;

13. The laminated solar cell according to claim 12, wherein one or more of the following (1) to (2) are satisfied:

(1) The material of the passivation layer comprises an oxide of aluminum;

(2) The thickness of the passivation layer is 0.5 nm-500 nm.

14. A method of manufacturing a laminated solar cell according to any one of claims 1 to 13, comprising the steps of:

The bottom solar cell and the top solar cell are stacked.

15. The method of claim 14, wherein the cross-sectional area S ₁ of the top solar cell along the second direction is less than the cross-sectional area S ₂ of the bottom solar cell;

16. A photovoltaic system comprising a laminated solar cell according to any one of claims 1 to 13.