Four-end laminated solar cell and preparation method thereof

Abstract

The invention relates to a four-end laminated solar cell and a preparation method thereof. The four-end laminated solar cell comprises a top cell and a bottom cell which are arranged in a laminated manner, the top cell comprises a transparent substrate, a first transparent electrode, a hole transport layer, a perovskite layer, an electron transport layer and a first metal electrode which are stacked in sequence; the top cell is provided with a groove, the groove penetrates through the first metal electrode, the electron transport layer and the perovskite layer along the thickness direction of the top cell, and the hole transport layer is exposed out of the groove; the band gap of the perovskite layer is 1.4 eV to 1.6 eV; the thickness of the perovskite layer ranges from 300 nm to 900 nm. According to the four-end laminated solar cell provided by the invention, a relatively high light utilization rate can be realized, so that relatively high photoelectric conversion efficiency can be realized.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a four-terminal stacked solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells have excellent photoelectric conversion performance. When used as top cells in combination with crystalline silicon solar cells, copper indium gallium selenide solar cells or organic solar cells, they can achieve all-round absorption of photons and thus demonstrate higher theoretical photoelectric conversion efficiency.

[0003] When using a traditional perovskite solar cell as a top cell, a semi-transparent perovskite solar cell needs to be prepared. Therefore, the perovskite layer needs to be thinned and the band gap of the perovskite layer needs to be widened. Usually, the appropriate band gap is above 1.68eV to achieve a better transparency effect so that the light not absorbed by the top cell can pass through the top cell and reach the bottom cell. However, a wide band gap perovskite solar cell will limit the photoelectric conversion efficiency of the tandem solar cell. Summary of the invention

[0004] Based on this, it is necessary to provide a four-terminal tandem solar cell and a preparation method thereof. The four-terminal tandem solar cell of the present application can have a higher photoelectric conversion efficiency.

[0005] In a first aspect, the present application provides a four-terminal tandem solar cell, comprising a top cell and a bottom cell arranged in a stacked manner;

[0006] The top cell comprises a transparent substrate, a first transparent electrode, a hole transport layer, a perovskite layer, an electron transport layer and a first metal electrode which are stacked in sequence; the top cell has a groove, the groove penetrates the first metal electrode, the electron transport layer and the perovskite layer along the thickness direction of the top cell, and the hole transport layer is exposed in the groove;

[0007] The band gap of the perovskite layer is 1.4 eV to 1.6 eV;

[0008] The thickness of the perovskite layer is 300nm~900nm.

[0009] In some embodiments, there are a plurality of grooves, and the plurality of grooves are arranged at intervals.

[0010] In some embodiments, the width of the notch of the groove is 0.05 cm to 0.15 cm.

[0011] In some embodiments, the ratio of the area of ​​the orthographic projection of the notch of the groove on the transparent substrate to the area of ​​the orthographic projection of the first metal electrode on the transparent substrate is (0.2-0.6):1.

[0012] In some embodiments, the material of the first transparent electrode includes at least one of ITO, IZO, IWO, ICO and AZO.

[0013] In some embodiments, the thickness of the first transparent electrode is 50 nm to 300 nm.

[0014] In some embodiments, the material of the hole transport layer includes at least one of 2PACz, NiO, PTAA and Spiro-OMeTAD.

[0015] In some embodiments, the hole transport layer has a thickness of 2 nm to 200 nm.

[0016] In some embodiments, the material of the perovskite layer includes a material having the following chemical formula: ABX 3 , where A is selected from FA + 、MA + , Cs + and Rb + At least one of, B is selected from Pb 2+ Sn 2+ and Sr 2+ At least one of, X is selected from Cl - Br - and I - At least one of .

[0017] In some embodiments, the material of the electron transport layer includes fullerene and its derivatives, SnO 2 、TiO 2 , ZnO and In 2 O 3 At least one of .

[0018] In some embodiments, the thickness of the electron transport layer is 10 nm to 50 nm.

[0019] In some embodiments, the material of the first metal electrode includes at least one of Al, Ag, Cu and Au.

[0020] In some embodiments, the thickness of the first metal electrode is 0.05 μm to 10 μm.

[0021] In some embodiments, the top battery further includes a modified barrier layer, which is disposed between the electron transport layer and the first metal electrode; the groove penetrates the first metal electrode, the modified barrier layer, the electron transport layer and the perovskite layer along the thickness direction of the top battery.

[0022] In some embodiments, the material of the modified barrier layer includes BCP and SnO 2 At least one of .

[0023] In some embodiments, the bottom cell includes a second metal electrode, a P-type doped silicon material layer, a first intrinsic silicon material layer, a silicon substrate, a second intrinsic silicon material layer, an N-type doped silicon material layer and a second transparent electrode stacked in sequence; the transparent substrate is arranged on a surface of the second transparent electrode away from the N-type doped silicon material layer.

[0024] In some embodiments, the four-terminal tandem solar cell further includes a transparent encapsulation layer, which is disposed on a surface of the first metal electrode away from the electron transport layer, and is used to encapsulate the top cell.

[0025] In a second aspect, the present application provides a method for preparing a four-terminal tandem solar cell, comprising the following steps:

[0026] A first transparent electrode, a hole transport layer, a perovskite layer, an electron transport layer and a first metal electrode are sequentially stacked on a transparent substrate, wherein the first metal electrode partially covers the electron transport layer; the band gap of the perovskite layer is 1.4 eV to 1.6 eV; and the thickness of the perovskite layer is 300 nm to 900 nm;

[0027] Using an etching solution to form a groove in the area not covered by the first metal electrode, the groove penetrates the electron transport layer and the perovskite layer along the thickness direction of the perovskite layer, so that the hole transport layer is exposed in the groove, thereby obtaining a top cell;

[0028] The top cell and the bottom cell are stacked.

[0029] In some embodiments, the etching solution includes at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0030] In the above-mentioned four-terminal tandem solar cell, the top cell has a groove, and the groove runs through the first metal electrode, the electron transport layer and the perovskite layer along the thickness direction of the top cell, and the hole transport layer is exposed in the groove. The groove in the top cell can provide a passage that allows most of the light to pass through, reducing the influence of the material and thickness of the perovskite layer on light transmission. Compared with the need to use a wide band gap and ultra-thin perovskite layer in traditional perovskite tandem solar cells, in the tandem solar cell of the present application, the top cell can use a perovskite layer with a normal band gap and thickness. In the above-mentioned four-terminal tandem solar cell, the band gap of the perovskite layer is 1.4eV~1.6eV, and the thickness of the perovskite layer is 300nm~900nm. Within the range of the band gap and thickness of the above-mentioned perovskite layer, a higher photoelectric conversion efficiency of the top cell can be achieved. The four-terminal tandem solar cell of the present application can achieve a higher light utilization rate, thereby achieving a higher photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of the structure of a four-terminal tandem solar cell provided in one embodiment of the present application;

[0032] FIG2 is a schematic diagram showing a structure in which a hole transport layer, a perovskite layer, an electron transport layer and a modified barrier layer are sequentially prepared on the surface of a first transparent electrode;

[0033] FIG3 is a schematic diagram of a structure in which a first metal electrode is formed on the basis of the structure shown in FIG2 ;

[0034] FIG. 4 is a schematic diagram of a structure in which a groove is formed on the basis of the structure shown in FIG. 3 .

[0035] Description of Reference Numerals

[0036] 10. Top cell; 11. Transparent substrate; 12. First transparent electrode; 13. Hole transport layer; 14. Perovskite layer; 15. Electron transport layer; 16. Modified barrier layer; 17. First metal electrode; 18. Groove; 20. Bottom cell; 21. Second metal electrode; 22. P-type doped silicon material layer; 23. First intrinsic silicon material layer; 24. Silicon substrate; 25. Second intrinsic silicon material layer; 26. N-type doped silicon material layer; 27. Second transparent electrode; 30. Transparent encapsulation layer. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0041] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] 1 , an embodiment of the present application provides a four-terminal stacked solar cell, comprising a top cell 10 and a bottom cell 20 stacked in layers; the top cell 10 comprises a transparent substrate 11, a first transparent electrode 12, a hole transport layer 13, a perovskite layer 14, an electron transport layer 15 and a first metal electrode 17 stacked in sequence; the top cell 10 has a groove 18, the groove 18 penetrates the first metal electrode 17, the electron transport layer 15 and the perovskite layer 14 along the thickness direction of the top cell 10, and the hole transport layer 13 is exposed in the groove 18; the band gap of the perovskite layer 14 is 1.4 eV~1.6 eV; the thickness of the perovskite layer 14 is 300nm~900nm.

[0043] In the above-mentioned four-terminal tandem solar cell, the top cell 10 has a groove 18, and the groove 18 penetrates the first metal electrode 17, the electron transport layer 15 and the perovskite layer 14 along the thickness direction of the top cell 10, and the hole transport layer 13 is exposed in the groove 18. The groove 18 in the top cell 10 can provide a passage that allows most of the light to pass through, reducing the influence of the material and thickness of the perovskite layer 14 on the light transmission. Compared with the need to select a wide bandgap and ultra-thin perovskite layer 14 in the traditional perovskite tandem solar cell, in the tandem solar cell of the present application, the top cell 10 can select a perovskite layer 14 with a normal bandgap and thickness. In the above-mentioned four-terminal tandem solar cell, the bandgap of the perovskite layer 14 is 1.4eV~1.6eV, and the thickness of the perovskite layer 14 is 300nm~900nm. Within the range of the bandgap and thickness of the perovskite layer 14, a higher photoelectric conversion efficiency of the top cell 10 can be achieved. The four-terminal stacked solar cell of the present application can achieve a higher light utilization rate, thereby achieving a higher photoelectric conversion efficiency.

[0044] It is understandable that the band gap of the perovskite layer 14 of the perovskite top cell 10 in the conventional tandem solar cell is usually above 1.68 eV, and the thickness of the perovskite layer 14 is usually between 200 nm and 600 nm. The halogen phase separation defect exists in the wide band gap perovskite top cell, which will lead to the stability of the perovskite top cell, and the photoelectric conversion efficiency of the wide band gap perovskite top cell is lower than that of the perovskite cell with a normal band gap of about 1.5 eV.

[0045] Optionally, the band gap of the perovskite layer 14 is 1.4eV, 1.42eV, 1.44eV, 1.46eV, 1.48eV, 1.5eV, 1.52eV, 1.54eV, 1.56eV, 1.58eV or 1.6eV, or, the band gap of the perovskite layer 14 may also be within the range between any two of the above band gaps.

[0046] Optionally, the thickness of the perovskite layer 14 is 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm or 900nm, or the thickness of the perovskite layer 14 may be within the range between any two of the above thicknesses.

[0047] In some embodiments, there are a plurality of grooves 18 , and the plurality of grooves 18 are arranged at intervals.

[0048] In some embodiments, the width of the notch of the groove 18 is 0.05 cm to 0.15 cm.

[0049] Optionally, the width of the notch of the groove 18 is 0.05 cm, 0.06 cm, 0.07 cm, 0.08 cm, 0.09 cm, 0.1 cm, 0.11 cm, 0.12 cm, 0.13 cm, 0.14 cm or 0.15 cm, or the width of the notch of the groove 18 may also be within the range between any two of the above widths.

[0050] In some embodiments, the ratio of the orthographic projection area of ​​the notch of the groove 18 on the transparent substrate 11 to the orthographic projection area of ​​the first metal electrode 17 on the transparent substrate 11 is (0.2-0.6):1.

[0051] It can be understood that the ratio of the total area of ​​the orthographic projection of the notch of the groove 18 on the transparent substrate 11 to the total area of ​​the orthographic projection of the first metal electrode 17 on the transparent substrate 11 is the ratio of the proportion of the light-transmitting area to the working area in the top cell 10. When there are multiple grooves 18, the above area is the total area of ​​the multiple grooves 18 and the total area of ​​the multiple first metal electrodes 17. When the ratio of the area of ​​the orthographic projection of the notch of the groove 18 on the transparent substrate 11 to the area of ​​the orthographic projection of the first metal electrode 17 on the transparent substrate 11 is too small, that is, the proportion of the light-transmitting area is too small, it will affect the utilization rate of light by the bottom cell 20, resulting in a low photoelectric conversion efficiency of the stacked solar cell. When the ratio of the area of ​​the orthographic projection of the notch of the groove 18 on the transparent substrate 11 to the area of ​​the orthographic projection of the first metal electrode 17 on the transparent substrate 11 is too large, it will affect the utilization rate of light by the top cell 10, resulting in a low photoelectric conversion efficiency of the stacked solar cell. Within the range of the ratio of the area of ​​the orthographic projection of the groove 18 on the transparent substrate 11 to the area of ​​the orthographic projection of the first metal electrode 17 on the transparent substrate 11 and within the range of the width of the groove 18, a balance between the light-transmitting area and the effective area of ​​the top battery 10 can be achieved, and a balance between the average light transmittance and the photoelectric conversion efficiency of the stacked solar cell can be achieved, so that the stacked solar cell has a higher photoelectric conversion efficiency.

[0052] Optionally, the ratio of the area of ​​the orthographic projection of the groove 18 on the transparent substrate 11 to the area of ​​the orthographic projection of the first metal electrode 17 on the transparent substrate 11 is 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1 or 0.6:1, or the ratio of the area of ​​the orthographic projection of the groove 18 on the transparent substrate 11 to the area of ​​the orthographic projection of the first metal electrode 17 on the transparent substrate 11 may also be within the range between any two of the above ratios.

[0053] In some embodiments, the material of the first transparent electrode 12 includes at least one of ITO, IZO, IWO, ICO and AZO.

[0054] In some embodiments, the thickness of the first transparent electrode 12 is 50 nm to 300 nm.

[0055] Optionally, the thickness of the first transparent electrode 12 is 50 nm, 100 nm, 150 nm, 200 nm, 250 nm or 300 nm, or the thickness of the first transparent electrode 12 may also be within a range between any two of the above thicknesses.

[0056] In some embodiments, the material of the hole transport layer 13 includes at least one of 2PACz, NiO, PTAA and Spiro-OMeTAD.

[0057] In some embodiments, the thickness of the hole transport layer 13 is 2 nm to 200 nm.

[0058] Optionally, the thickness of the hole transport layer 13 is 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm or 200 nm, or the thickness of the hole transport layer 13 may be within the range between any two of the above thicknesses.

[0059] In some embodiments, the material of the perovskite layer 14 includes a material having the following chemical formula: ABX 3 , where A is selected from FA + 、MA + , Cs + and Rb + At least one of, B is selected from Pb 2+ Sn 2+ and Sr 2+ At least one of, X is selected from Cl - Br - and I - At least one of .

[0060] In some embodiments, the material of the electron transport layer 15 includes fullerene and its derivatives, SnO 2 、TiO 2 , ZnO and In 2 O 3 At least one of .

[0061] In some embodiments, the thickness of the electron transport layer 15 is 10 nm to 50 nm.

[0062] Optionally, the thickness of the electron transport layer 15 is 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm, or the thickness of the electron transport layer 15 may also be within the range between any two of the above thicknesses.

[0063] In some embodiments, the material of the first metal electrode 17 includes at least one of Al, Ag, Cu and Au.

[0064] In some embodiments, the thickness of the first metal electrode 17 is 0.05 μm-10 μm.

[0065] Optionally, the thickness of the first metal electrode 17 is 0.05μm, 0.1μm, 0.2μm, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm or 10μm, or the thickness of the first metal electrode 17 may be within the range between any two of the above thicknesses.

[0066] In some embodiments, the top battery 10 further includes a modified barrier layer 16, which is disposed between the electron transport layer 15 and the first metal electrode 17; the groove 18 penetrates the first metal electrode 17, the modified barrier layer 16, the electron transport layer 15 and the perovskite layer 14 along the thickness direction of the top battery 10.

[0067] In some embodiments, the material of the modified barrier layer 16 includes BCP and SnO 2 At least one of .

[0068] In some embodiments, the bottom cell 20 includes a second metal electrode 21, a P-type doped silicon material layer 22, a first intrinsic silicon material layer 23, a silicon substrate 24, a second intrinsic silicon material layer 25, an N-type doped silicon material layer 26 and a second transparent electrode 27 stacked in sequence; the transparent substrate 11 is disposed on the surface of the second transparent electrode 27 away from the N-type doped silicon material layer 26.

[0069] In some embodiments, the four-terminal tandem solar cell further includes a transparent encapsulation layer 30 . The transparent encapsulation layer 30 is disposed on a surface of the first metal electrode 17 away from the electron transport layer 15 . The transparent encapsulation layer 30 is used to encapsulate the top cell 10 .

[0070] Exemplarily, the material of the transparent encapsulation layer 30 may be encapsulation glue. When the encapsulation glue is used to encapsulate the top cell 10, the encapsulation glue may fill the groove 18. The transparent encapsulation layer 30 may also be glass. When the top cell 10 is encapsulated with glass, the groove 18 is not filled.

[0071] Another embodiment of the present application provides a method for preparing a four-terminal tandem solar cell, comprising the following steps:

[0072] A first transparent electrode 12, a hole transport layer 13, a perovskite layer 14, an electron transport layer 15 and a first metal electrode 17 are sequentially stacked on a transparent substrate 11, and the first metal electrode 17 partially covers the electron transport layer 15; the band gap of the perovskite layer 14 is 1.4eV~1.6eV; the thickness of the perovskite layer 14 is 300nm~900nm;

[0073] An etching solution is used to form a groove 18 in the area not covered by the first metal electrode 17. The groove 18 penetrates the first metal electrode 17, the electron transport layer 15 and the perovskite layer 14 along the thickness direction of the perovskite layer 14, so that the hole transport layer 13 is exposed in the groove 18, thereby obtaining the top cell 10;

[0074] The top cell 10 and the bottom cell 20 are stacked.

[0075] It is understandable that after preparing the first metal electrode 17, since the first metal electrode 17 partially covers the electron transport layer 15, the etching solution can be directly used to form the groove 18 in the area not covered by the first metal electrode 17, that is, the electron transport layer 15 and the perovskite layer 14 can be anisotropically etched by the etching solution, thereby forming a groove 18 along the thickness direction of the top battery 10, so that the hole transport layer 13 is exposed in the groove 18. The method for preparing the groove 18 is simple and low in cost. Compared with the process of opening holes by laser etching, the cost of laser etching is extremely high, and it is difficult to achieve non-destructive etching. The preparation method of the four-terminal stacked solar cell in the present application can realize the preparation of low-cost and lossless stacked solar cells, while realizing stacked solar cells with higher photoelectric conversion efficiency.

[0076] In some embodiments, the etching solution includes at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0077] The above etching solution is selected so as not to cause damage to the first metal electrode 17 and the hole transport layer 13 , and to achieve a good non-destructive etching effect on the electron transport layer 15 and the perovskite layer 14 to prepare the groove 18 .

[0078] In some embodiments, the method for preparing a four-terminal tandem solar cell comprises the following steps:

[0079] S10: providing a transparent substrate 11, on the surface of which a first transparent electrode 12 is disposed; and preparing a hole transport layer 13, a perovskite layer 14, an electron transport layer 15 and a modified blocking layer 16 stacked in sequence on the surface of the first transparent electrode 12.

[0080] 2 , which is a schematic structural diagram of sequentially preparing a hole transport layer 13 , a perovskite layer 14 , an electron transport layer 15 and a modified barrier layer 16 on the surface of a first transparent electrode 12 .

[0081] In some embodiments, preparing the hole transport layer 13 on the surface of the first transparent electrode 12 comprises the following steps:

[0082] Applying the hole transport layer 13 material solution on the surface of the first transparent electrode 12;

[0083] Through the annealing treatment, the hole transport layer 13 is obtained.

[0084] In some embodiments, before coating the hole transport layer 13 material solution on the surface of the first transparent electrode 12, the following steps are also included:

[0085] The surface of the first transparent electrode 12 is subjected to plasma treatment.

[0086] In some embodiments, preparing the perovskite layer 14 on the surface of the hole transport layer 13 comprises the following steps:

[0087] dissolving a perovskite precursor material in a solvent to obtain a perovskite precursor solution;

[0088] The perovskite precursor solution is coated on the surface of the hole transport layer 13 and crystallized into a film to prepare the perovskite layer 14 .

[0089] In some embodiments, the electron transport layer 15 is formed on the surface of the perovskite layer 14 by evaporation.

[0090] In some embodiments, the modified blocking layer 16 is prepared by evaporation on the surface of the electron transport layer 15 .

[0091] S20 : ​​preparing a first metal electrode 17 on the surface of the modified barrier layer 16 .

[0092] Referring to FIG. 3 , FIG. 3 is a schematic diagram of a structure in which a first metal electrode 17 layer is prepared based on the structure shown in FIG. 2 .

[0093] In some embodiments, the first metal electrode 17 layer is a patterned first metal electrode 17 layer, and the first metal electrode 17 layer partially covers the surface of the modified barrier layer 16 .

[0094] S30: using an etching solution to form a groove 18 in the area not covered by the first metal electrode 17, the groove 18 penetrates the modified barrier layer 16, the electron transport layer 15 and the perovskite layer 14 along the thickness direction of the top battery 10, so that the hole transport layer 13 is exposed in the groove 18, and the top battery 10 is obtained.

[0095] Referring to FIG. 4 , FIG. 4 is a schematic diagram of a structure in which a groove 18 is formed on the basis of the structure shown in FIG. 3 .

[0096] S40: providing a bottom cell 20, stacking the top cell 10 and the bottom cell 20, disposing a transparent encapsulation layer 30 on the surface of the first metal electrode 17, encapsulating the top cell 10, and obtaining a four-terminal stacked solar cell.

[0097] The following are specific embodiments

[0098] Example 1

[0099] Referring again to FIG. 1 , the four-terminal tandem solar cell in Example 1 includes a top cell 10 and a bottom cell 20 that are stacked, wherein the top cell 10 is a perovskite solar cell, and the bottom cell 20 is a crystalline silicon solar cell.

[0100] The top cell 10 includes a transparent substrate 11, a first transparent electrode 12, a hole transport layer 13, a perovskite layer 14, an electron transport layer 15, a modified barrier layer 16 and a first metal electrode 17 which are stacked in sequence; the top cell 10 has a groove 18, which penetrates the first metal electrode 17, the modified barrier layer 16, the electron transport layer 15 and the perovskite layer 14 along the thickness direction of the perovskite layer 14, and the hole transport layer 13 is exposed in the groove 18.

[0101] The material of the perovskite layer 14 is Cs 0.08 FA 0.92 PbI 3 , band gap of 1.55 eV, thickness of 850 nm. The ratio of the orthogonal projection area of ​​the notch of the groove 18 on the transparent substrate 11 to the orthogonal projection area of ​​the first metal electrode 17 on the transparent substrate 11 is 0.5:1. The material of the first transparent electrode 12 includes ITO, the material of the hole transport layer 13 includes 2PACz, and the material of the electron transport layer 15 is C 60 , the material of the modified barrier layer 16 is BCP, and the material of the first metal electrode 17 is Ag.

[0102] The bottom cell 20 includes a second metal electrode 21, a P-type doped silicon material layer 22, a first intrinsic silicon material layer 23, a silicon substrate 24, a second intrinsic silicon material layer 25, an N-type doped silicon material layer 26 and a second transparent electrode 27 which are stacked in sequence; the transparent substrate 11 is arranged on the surface of the second transparent electrode 27 away from the N-type doped silicon material layer 26. The material of the second metal electrode 21 is Ag, the P-type doped silicon material layer 22 is a boron-doped polysilicon layer, the first intrinsic silicon material layer 23 and the second intrinsic silicon material layer 25 are intrinsic amorphous silicon layers, the N-type doped silicon material layer 26 is a phosphorus-doped polysilicon layer, and the material of the second transparent electrode 27 is ITO.

[0103] Comparative Example 1

[0104] The structure of the four-terminal tandem solar cell in Comparative Example 1 is basically the same as that in Example 1, except that the material of the perovskite layer is Cs 0.05 FA 0.8 MA 0.15 PbI 2.25 Br 0.75 , the band gap is 1.68 eV, the thickness is 450 nm, and the top cell has no groove.

[0105] Photoelectric conversion tests were performed on the laminated solar cells in Example 1 and Comparative Example 1. The test results are shown in Table 1 below:

[0106] Table 1

[0107]

[0108] It can be seen from the test results that the four-terminal tandem solar cell in Example 1 has a photoelectric conversion efficiency that is significantly higher than that of the four-terminal tandem solar cell in Comparative Example 1.

[0109] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. A four-terminal tandem solar cell, characterized in that: including a top cell and a bottom cell arranged in a stacked manner; The top cell comprises a transparent substrate, a first transparent electrode, a hole transport layer, a perovskite layer, an electron transport layer and a first metal electrode which are stacked in sequence; the top cell has a groove, the groove penetrates the first metal electrode, the electron transport layer and the perovskite layer along the thickness direction of the top cell, and the hole transport layer is exposed in the groove; The band gap of the perovskite layer is 1.4 eV to 1.6 eV; The thickness of the perovskite layer is 300nm~900nm.

2. The four-terminal tandem solar cell according to claim 1, characterized in that: There are multiple grooves, and the multiple grooves are arranged at intervals.

3. The four-terminal tandem solar cell according to claim 1, characterized in that: The width of the notch of the groove is 0.05 cm to 0.15 cm; and / or, The ratio of the area of ​​the orthographic projection of the notch of the groove on the transparent substrate to the area of ​​the orthographic projection of the first metal electrode on the transparent substrate is (0.2-0.6):

1.

4. The four-terminal tandem solar cell according to claim 1, characterized in that: The top battery meets at least one of the following characteristics: (1) The material of the first transparent electrode includes at least one of ITO, IZO, IWO, ICO and AZO; (2) The thickness of the first transparent electrode is 50 nm to 300 nm; (3) The material of the hole transport layer includes at least one of 2PACz, NiO, PTAA and Spiro-OMeTAD; (4) The thickness of the hole transport layer is 2 nm to 200 nm; (5) The material of the perovskite layer includes a material having the following chemical formula: ABX3, wherein A is selected from FA + 、MA + , Cs + and Rb + At least one of, B is selected from Pb 2+ Sn 2+ and Sr 2+ At least one of, X is selected from Cl - Br - and I - At least one of; (6) The material of the electron transport layer includes at least one of fullerene and its derivatives, SnO2, TiO2, ZnO and In2O3; (7) The thickness of the electron transport layer is 10 nm to 50 nm; (8) The material of the first metal electrode includes at least one of Al, Ag, Cu and Au; (9) The thickness of the first metal electrode is 0.05 μm to 10 μm.

5. The four-terminal tandem solar cell according to claim 1, characterized in that: The top cell further includes a modified barrier layer, which is disposed between the electron transport layer and the first metal electrode; the groove penetrates the first metal electrode, the modified barrier layer, the electron transport layer and the perovskite layer along the thickness direction of the top cell.

6. The four-terminal tandem solar cell according to claim 5, characterized in that: The material for modifying the barrier layer includes at least one of BCP and SnO2.

7. The four-terminal tandem solar cell according to any one of claims 1 to 6, characterized in that: The bottom cell comprises a second metal electrode, a P-type doped silicon material layer, a first intrinsic silicon material layer, a silicon substrate, a second intrinsic silicon material layer, an N-type doped silicon material layer and a second transparent electrode which are stacked in sequence; The transparent substrate is disposed on a surface of the second transparent electrode away from the N-type doped silicon material layer.

8. The four-terminal tandem solar cell according to any one of claims 1 to 6, characterized in that: The four-terminal stacked solar cell further comprises a transparent encapsulation layer, which is arranged on a surface of the first metal electrode away from the electron transport layer, and is used to encapsulate the top cell.

9. A method for preparing a four-terminal tandem solar cell, characterized in that: The steps include: A first transparent electrode, a hole transport layer, a perovskite layer, an electron transport layer and a first metal electrode are sequentially stacked on a transparent substrate, wherein the first metal electrode partially covers the electron transport layer; the band gap of the perovskite layer is 1.4 eV to 1.6 eV; and the thickness of the perovskite layer is 300 nm to 900 nm; Using an etching solution to form a groove in the area not covered by the first metal electrode, the groove penetrates the electron transport layer and the perovskite layer along the thickness direction of the perovskite layer, so that the hole transport layer is exposed in the groove, thereby obtaining a top cell; The top cell and the bottom cell are stacked.

10. The method for preparing a four-terminal tandem solar cell according to claim 9, characterized in that: The etching solution includes at least one of N,N-dimethylformamide and dimethyl sulfoxide.

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