A perovskite / topcon laminated cell and a preparation method and application thereof

Abstract

The application provides a perovskite / TOPCon laminated cell and a preparation method and application thereof, and relates to the technical field of solar cells.The perovskite / TOPCon laminated cell of the application forms a thinned Poly layer second region and a non-thinned Poly layer first region by partially thinning a third transport layer Poly layer in a TOPCon bottom cell, the TCO interconnection layer is not arranged above the thinned Poly layer second region, and the perovskite cell and the TOPCon bottom cell are connected through a local TCO interconnection layer.By partitioning and thinning the Poly layer in the TOPCon bottom cell and partitioning and arranging the TCO interconnection layer, a local interconnection structure of the TCO interconnection layer is formed, the proportion of the TCO interconnection layer and the Poly layer is reduced, parasitic absorption is reduced, a local interconnection structure of the TCO interconnection layer is formed, the risk of electric leakage is reduced, the yield of the cell is effectively improved, the overall parasitic absorption is reduced, and the efficiency of the cell is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a perovskite / TOPCon stacked cell and a preparation method and application thereof. BACKGROUND

[0002] TOPCon cell is one of the mainstream high-efficiency bottom cells in the current stacked cells, which realizes a substantial increase in voltage by relying on the passivated contact structure. Perovskite / TOPCon stacked solar cell is an effective way to break through the efficiency limit of single-junction solar cells. By using a wide-bandgap perovskite as a top cell to absorb short-wavelength sunlight and a narrow-bandgap TOPCon cell as a bottom cell to absorb long-wavelength sunlight, the utilization rate of the solar spectrum can be improved, and the thermal relaxation loss of carriers can be reduced, thereby improving the photoelectric conversion efficiency. However, there are still many defects in the current perovskite / TOPCon stacked cell. On the one hand, the intermediate interconnection layer of the perovskite / TOPCon stacked cell usually adopts transparent conductive oxide (TCO). This type of transparent conductive film has high cost and small lateral resistance. The lateral conductivity is too high, and the carriers are easy to penetrate the defect points of the top cell to cause short circuit of the top cell, which has the defects of lateral leakage and the like, greatly reduces the yield, and the TCO has strong long-wave parasitic absorption, which has serious parasitic absorption and reduces the short-circuit current. On the other hand, the Poly layer in the TOPCon cell also causes serious parasitic absorption, which reduces the short-circuit current density, and finally seriously affects the cell efficiency, so the Poly layer needs to be thinned. In order to increase light absorption, the Poly-finger technology is used in single-junction TOPCon cells to thin the Poly layer below the non-metallic contact area, but the too thin Poly layer in the single-junction TOPCon cell has the problem of silver paste corrosion and metalization damage. Therefore, it is urgent to provide a perovskite / TOPCon stacked cell which can reduce the parasitic absorption of the perovskite / TOPCon stacked cell and effectively improve the yield.

[0003] The prior art CN118540963A discloses a laminated battery, comprising a first electrode, a first polarity transmission layer, a perovskite layer, a first interface passivation layer, a second interface passivation layer, a second polarity transmission layer, a buffer layer, a third polarity transmission layer, a crystalline silicon layer, a fourth polarity transmission layer and a second electrode; in the direction from the perovskite layer to the crystalline silicon layer, the first electrode, the first polarity transmission layer and the perovskite layer are sequentially laminated, and the crystalline silicon layer, the fourth polarity transmission layer and the second electrode are sequentially laminated; a plurality of alternately arranged non-thinned Poly layer first regions and thinned Poly layer second regions are formed between the perovskite layer and the crystalline silicon layer, the second polarity transmission layer, the buffer layer and the third polarity transmission layer are sequentially laminated on the perovskite layer and located in the non-thinned Poly layer first region, and the first interface passivation layer and the second interface passivation layer are sequentially laminated on the perovskite layer and located in the thinned Poly layer second region; in the thickness direction of the laminated battery, the laminated structure of the second polarity transmission layer, the buffer layer and the third polarity transmission layer at least partially overlaps with the projection of the first electrode in the same projection plane. This prior art needs to re-construct a multi-layer "optical funnel" and prepare a multi-layer passivation layer to improve parasitic absorption, the preparation structure is complex, and the problem of low yield is not solved. SUMMARY

[0004] The present application is directed to the defects and deficiencies of the current perovskite / TOPCon laminated battery, which has serious parasitic absorption, resulting in low battery efficiency, and the transparent conductive oxide composite layer has high lateral conductivity, resulting in low battery yield, and provides a perovskite / TOPCon laminated battery, which divides and thins the Poly layer in the TOPCon bottom cell and divides and sets the TCO interconnection layer to form a local interconnection structure of the TCO interconnection layer, reduces the risk of electric leakage, effectively improves the battery yield, reduces the overall parasitic absorption, and improves the battery efficiency.

[0005] Another object of the present application is to provide a preparation method of a perovskite / TOPCon laminated battery.

[0006] Still another object of the present application is to provide an application of a perovskite / TOPCon laminated battery in photovoltaic power generation.

[0007] Still another object of the present application is to provide a photovoltaic system.

[0008] In a first aspect, the present application provides a perovskite / TOPCon laminated battery, wherein a third transmission layer Poly layer in a TOPCon bottom cell is partially thinned to form a thinned Poly layer second region and a non-thinned Poly layer first region, there is no TCO interconnection layer above the thinned Poly layer second region, and a perovskite battery and a local TCO interconnection layer of a TOPCon bottom cell are connected.

[0009] According to the perovskite / TOPCon stacked cell provided by the application, preferably, the area of the thinned Poly layer second region accounts for 20-80% of the total area of the third transport layer Poly layer.

[0010] According to the perovskite / TOPCon stacked cell provided by the application, preferably, the thinned Poly layer second region comprises multiple discontinuous thinned Poly layer regions.

[0011] According to the perovskite / TOPCon stacked cell provided by the application, preferably, the non-thinned Poly layer first region and the thinned Poly layer second region are arranged alternately.

[0012] According to the perovskite / TOPCon stacked cell provided by the application, preferably, the thickness of the non-thinned Poly layer first region is 70-100 nm, and the thickness of the thinned Poly layer second region is 40-60% of the original thickness.

[0013] According to the perovskite / TOPCon stacked cell provided by the application, preferably, the thickness of the TCO interconnection layer is 30-70 nm.

[0014] According to the perovskite / TOPCon stacked cell provided by the application, preferably, the TOPCon bottom cell comprises a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer and a back electrode.

[0015] In a second aspect, the application further provides a preparation method of a perovskite / TOPCon stacked cell, comprising the following steps:

[0016] S1: performing texturing treatment on a silicon substrate, preparing a fourth transport layer and a passivation layer on the back surface of the silicon wafer in sequence, performing back surface metallization, and preparing a back electrode;

[0017] S2: preparing a tunneling layer, a third transport layer, a TCO interconnection layer, a second transport layer, a perovskite layer, a first transport layer, a buffer layer and a TCO layer on the front surface of the silicon wafer in sequence, performing front surface metallization, and preparing a top electrode on the TCO layer.

[0018] In a third aspect, the application further provides an application of a perovskite / TOPCon stacked cell in the field of photovoltaic power generation.

[0019] In a fourth aspect, the application further provides a photovoltaic system comprising a cell assembly composed of a perovskite / TOPCon stacked cell.

[0020] Beneficial effects:

[0021] The application provides a perovskite / TOPCon stacked cell, by means of partial thinning of a Poly layer in a TOPCon bottom cell and partial setting of a TCO interconnection layer, forming a local interconnection structure of the TCO interconnection layer, reducing the proportion of the TCO interconnection layer and the Poly layer, reducing parasitic absorption, and at the same time forming a local interconnection structure of the TCO interconnection layer, reducing the risk of electric leakage, effectively improving the yield of the cell, reducing the overall parasitic absorption, and improving the efficiency of the cell. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to make the content of the application easier to be clearly understood, the application will be further described in detail below according to specific embodiments of the application and in conjunction with the drawings.

[0023] Figure 1 is a structural schematic diagram of the perovskite / TOPCon stacked cell of the application.

[0024] Figure 2 is a structural schematic diagram of the first area of the non-thinned Poly layer and the second area of the thinned Poly layer after the third transmission layer Poly layer of the application is thinned.

[0025] Figure 3 is a structural schematic diagram of the first area of the non-thinned Poly layer and the second area of the thinned Poly layer after the third transmission layer Poly layer of the application is thinned.

[0026] Figure 4 is a structural schematic diagram of the first area of the non-thinned Poly layer and the second area of the thinned Poly layer after the third transmission layer Poly layer of the application is thinned. DETAILED DESCRIPTION

[0027] The following examples are used to illustrate the application, but are not used to limit the scope of the application. If the specific technology or condition is not specified in the examples, the technology or condition described in the literature in the art or according to the product manual is used. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be purchased through a regular channel.

[0028] In the detailed description, the application provides a perovskite / TOPCon stacked cell, by means of partial thinning of a third transmission layer Poly layer in a TOPCon bottom cell to form a second area of a thinned Poly layer and a first area of a non-thinned Poly layer, and by means of no TCO interconnection layer above the second area of the thinned Poly layer, local TCO interconnection layer connection of a perovskite cell and a TOPCon bottom cell.

[0029] The present application aims to reduce the parasitic absorption problem of the TCO interconnection layer and the Poly layer, divide the third transport layer Poly layer in the TOPCon bottom cell into two parts, thin the thickness of one part of the Poly layer, and there is no TCO interconnection layer (transparent conductive layer) above it, and the other part of the Poly layer is prepared normally, and there is a TCO interconnection layer above it. By reducing the proportion of TCO interconnection layer and Poly layer, the parasitic absorption is reduced, and at the same time, the local interconnection structure of TCO interconnection layer is formed, the risk of electric leakage is reduced, and the yield is improved.

[0030] The transparent conductive oxide composite layer (TCO interconnection layer) has high lateral conductivity, and when there are defects such as particles in the cell preparation process, the perovskite top layer TCO layer and the TCO interconnection layer will be conductive, causing the whole cell to fail, greatly reducing the yield. The present application controls the thinning of the Poly layer in the second area without TCO interconnection layer, so that the perovskite top cell and the TOPCon bottom cell are connected by local TCO interconnection layer, greatly reducing the probability of conduction between the perovskite top layer TCO layer and the TCO interconnection layer, reducing the risk of electric leakage, and improving the yield of the cell.

[0031] The larger the area ratio of the non-thinned Poly layer first area, the more conducive to charge transmission. The larger the area ratio of the thinned Poly layer second area, the more conducive to reducing parasitic absorption and improving optical loss. In some specific embodiments, in order to optimize the overall performance, the present application preferably controls the area of the thinned Poly layer second area to be 20-80% of the total area of the third transport layer Poly layer, for example, it can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, etc. Point value or any range value composed of.

[0032] And the perovskite / TOPCon stacked cell of the present application is a stacked cell, and there is no problem of silver paste corrosion and metallization of the excessively thin Poly layer in the single-junction TOPCon cell.

[0033] In some specific embodiments, the part of the third transport layer Poly layer mentioned in the present application is preferably a plurality of non-continuous thinned Poly layer regions.

[0034] The area of the non-thinned Poly layer first area and the thinned Poly layer second area (thinned area) mentioned in the present application can be flexibly adjusted. From the plan view, the shape of the thinned area can also be adjusted at will, and can include any one or a combination of regular and irregular patterns, which can be any one of circular, rectangular, etc. The larger the area ratio of the non-thinned Poly layer first area, the more conducive to charge transmission. The larger the area ratio of the thinned Poly layer second area, the more conducive to reducing parasitic absorption and improving optical loss.

[0035] In some embodiments, the plurality of discontinuous thinning Poly layer regions mentioned in the present application can specifically form a plurality of discontinuous thinning Poly layer regions in which the non-thinning Poly layer first regions and the thinning Poly layer second regions are arranged alternately.

[0036] In some embodiments, the non-thinning Poly layer first region mentioned in the present application has a thickness of 70-100 nm, and the thinning Poly layer second region formed after thinning has a thickness of 40-60% of the original thickness. For example, it can be 40%, 50%, 60%, etc. or any range value.

[0037] In some embodiments, the TCO interconnection layer mentioned in the present application has a thickness of 30-70 nm.

[0038] The TCO interconnection layer can be any one of ITO (indium tin oxide), IZO (indium zinc oxide), FTO (fluorine-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), and IWO (indium tungsten oxide), and the thickness can be 30-70 nm.

[0039] The perovskite / TOPCon stacked cell structure mentioned in the present application specifically has, from top to bottom, a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, a second transport layer, a TCO interconnection layer, a third transport layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode. The third transport layer is partially thinned to form a thinning Poly layer second region and a non-thinning Poly layer first region, and the TCO interconnection layer is not present above the thinning second region.

[0040] The third transport layer Poly layer is a polysilicon layer, which can be N-type doped polysilicon or P-type doped polysilicon. The third transport layer is divided into two regions: the non-thinning Poly layer first region has a polysilicon layer thickness of 70-100 nm and is covered with a TCO interconnection layer, and the thinning Poly layer second region is thinned. The third transport layer of the thinning Poly layer second region has a thickness less than that of the non-thinning Poly layer first region, and the upper surface is free of the TCO interconnection layer.

[0041] The perovskite cell includes a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, and a second transport layer. The first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0042] The electron transport layer is SnO x (tin oxide), TiO x (titanium oxide), ZnO (zinc oxide), WO x (tungsten oxide), C 60Any one or more of the following electron transport materials: fullerene, PCBM (fullerene derivative), etc. The electron transport layer has a thickness of 1-200 nm.

[0043] The hole transport layer is made of any one or more of the following hole transport materials: NiO x (oxidized nickel), MoO x (oxidized molybdenum), V2O5 (oxidized vanadium), Cu2O (oxidized copper), PTAA, Spiro-OMeTAD, SAM, etc. The hole transport layer has a thickness of 1-200 nm.

[0044] The perovskite layer has a chemical formula of ABX3, wherein A includes organic cations, inorganic cations, or organic-inorganic hybrid cations, B is an inorganic cation, and X is a halide anion. The perovskite layer has a thickness of 0.1-2 um.

[0045] In some embodiments, a passivation layer can also be added between the perovskite layer and the first transport layer.

[0046] The buffer layer is made of any one of the following materials: SnO2, MoO3, LiF, TiO2, and has a thickness of 1-100 nm.

[0047] The TCO layer is made of any one of the following transparent conductive oxides: ITO (tin-doped indium oxide), IZO (indium-doped zinc oxide), FTO (fluorine-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), IWO (tungsten-doped indium oxide), etc., and has a thickness of 1-100 nm.

[0048] The structure of the specific TOPCon bottom cell in the perovskite / TOPCon stacked cell mentioned in the present application includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode.

[0049] The silicon substrate mentioned in the present application can be an N-type silicon wafer or a P-type silicon wafer, and has a thickness of 50-200 um.

[0050] In some embodiments, the third transport layer and the fourth transport layer can be composed in any of the following ways:

[0051] The third transport layer is an N-type polycrystalline silicon layer, and the fourth transport layer is a P-type doped monocrystalline silicon layer or a P-type polycrystalline silicon layer.

[0052] The third transport layer is a P-type polycrystalline silicon layer, and the fourth transport layer is an N-type doped monocrystalline silicon layer or an N-type polycrystalline silicon layer.

[0053] In some embodiments, the present application also specifically provides a preparation method of a perovskite / TOPCon stacked cell, which includes the following steps:

[0054] S1: texturing the silicon substrate, preparing the fourth transport layer and the passivation layer on the back surface of the silicon wafer in sequence, back surface metallization, and preparing the back electrode;

[0055] S2: preparing the tunneling layer, the third transport layer, the TCO interconnection layer, the second transport layer, the perovskite layer, the first transport layer, the buffer layer, and the TCO layer on the front surface of the silicon wafer in sequence, front surface metallization, and preparing the top electrode on the TCO layer.

[0056] In some embodiments, the preparation method of the perovskite / TOPCon stacked cell mentioned in the present application further comprises the following steps in more detail:

[0057] 1) texturing the silicon substrate;

[0058] 2) preparing the fourth transport layer on the back surface of the silicon wafer;

[0059] 3) preparing the third transport layer on the front surface: sequentially depositing a tunneling oxide layer and a polysilicon layer, and then doping and diffusing the polysilicon on the front surface to form the third transport layer, wherein the thickness of the tunneling oxide layer is 0.5-2 nm, the thickness of the doped polysilicon is 30-300 nm, and the third transport layer and the fourth transport layer have opposite polarities;

[0060] 4) depositing a passivation layer on the back surface, the passivation layer can be one or more of silicon nitride, aluminum oxide, silicon oxide, silicon oxynitride, and silicon carbide, and the thickness of the passivation layer is 1-100 nm;

[0061] 5) back surface metallization to prepare a metal grid back electrode;

[0062] 6) depositing a TCO interconnection layer on the front surface, and the TCO interconnection layer and the third transport layer Poly layer form an interval alternating structure;

[0063] 7) preparing the second transport layer on the TCO interconnection layer and the passivation layer on the front surface;

[0064] 8) preparing the perovskite layer on the hole transport layer;

[0065] 9) preparing the first transport layer on the perovskite layer;

[0066] 10) preparing the buffer layer on the electron transport layer;

[0067] 11) depositing the TCO layer on the buffer layer;

[0068] 12) front surface metallization to prepare a metal grid top electrode on the TCO layer.

[0069] In some embodiments, the present application also specifically provides a perovskite / TOPCon stacked cell for use in photovoltaic power generation.

[0070] In the specific embodiments, the application also specifically protects a photovoltaic system comprising a cell assembly composed of the perovskite / TOPCon tandem cell.

[0071] Embodiment 1

[0072] A perovskite / TOPCon tandem cell, as shown in Figure 1 includes a perovskite cell, a TCO interconnection layer and a TOPCon bottom cell.

[0073] The perovskite cell includes a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer and a second transport layer. Among the first and second transport layers, the first transport layer is an electron transport layer and the second transport layer is a hole transport layer.

[0074] The structure of the TOPCon bottom cell includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer and a back electrode. The third transport layer is partially thinned to form a thinned Poly layer second region and a non-thinned first region, and the TCO interconnection layer is not present above the thinned Poly layer second region. The area of the thinned Poly layer second region accounts for 40% of the total area of the third transport layer Poly layer. The thickness of the non-thinned Poly layer first region is 80 nm, and the thickness of the thinned Poly layer second region formed after thinning is 40 nm.

[0075] The thickness of the TCO interconnection layer is 30 nm.

[0076] The structure of the third transport layer is shown in Figure 2 includes a non-continuous thinned Poly layer second region and a non-thinned first region formed by thinning. The thinned Poly layer second region is composed of multiple square regions, which are uniformly dispersed on the Poly layer.

[0077] The embodiment also provides a preparation method of a perovskite / TOPCon tandem cell, which specifically includes the following steps:

[0078] 1. Texturing treatment is performed on an N-type silicon wafer, and the thickness of the silicon wafer is 100 nm;

[0079] 2. Boron diffusion is performed on the back surface of the silicon wafer;

[0080] 3. After the boron diffusion is completed, the BSG (borosilicate glass) on the front surface and the edge is removed, and then the front surface is subjected to alkali etching, and the BSG on the back surface is retained;

[0081] 4. The front surface is sequentially deposited with a tunneling oxide layer and a polysilicon layer, and then the polysilicon is subjected to phosphorus diffusion;

[0082] 5、After phosphorus extension, remove the (phosphate glass) PSG on the back and edge, retain the PSG on the front, form a tunneling layer and a third transport layer;

[0083] 6、Alkaline cleaning removes the backside poly, acid cleaning removes the backside BSG and the frontside PSG, forming a fourth transport layer;

[0084] 7、Depositing aluminum oxide and silicon nitride layers on the back in sequence to form a passivation layer;

[0085] 8、Backside metallization to prepare the back electrode;

[0086] 9、Depositing ITO on the front to prepare the interconnection layer;

[0087] 10、Laser removal of part of the ITO and Poly layer on the front to form a thinned Poly layer second area and a non-thinned Poly layer first area, and no TCO interconnection layer above the thinned Poly layer second area;

[0088] 11、Magnetron deposition of NiO x to form a second transport layer;

[0089] 12、Solution preparation of FAMAPbIBr3 to prepare a perovskite layer;

[0090] 13、Evaporation of C 60 to form a first transport layer;

[0091] 14、ALD preparation of SnO2 to form a buffer layer;

[0092] 15、Magnetron ITO preparation of a TCO layer;

[0093] 16、Frontside metallization to prepare the top electrode.

[0094] The top cell and the bottom cell are connected by a local TCO interconnection layer, reducing the damage caused by magnetron sputtering during deposition of the transparent conductive oxide, reducing the parasitic absorption of the TCO interconnection layer, and reducing the risk of short circuit.

[0095] Reducing the thickness of part of the poly layer in the TOPCon bottom cell reduces parasitic absorption and improves optical loss.

[0096] Example 2

[0097] A perovskite / TOPCon stacked cell, as shown in Figure 1 , includes a perovskite cell, a TCO interconnection layer, and a TOPCon bottom cell.

[0098] The perovskite cell includes a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, and a second transport layer. The first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0099] The structure of the TOPCon bottom cell includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode. The third transport layer is partially thinned to form a thinned Poly layer second region and an unthinned first region. The thinned second region is free of a TCO interconnection layer. The area of the thinned Poly layer second region accounts for 40% of the total area of the third transport layer Poly layer. The thickness of the unthinned first region is 80 nm, and the thickness of the thinned Poly layer second region is 40 nm.

[0100] The thickness of the TCO interconnection layer is 30 nm.

[0101] The structure of the third transport layer is shown in Figure 3 The third transport layer includes a discontinuous thinned Poly layer second region formed by thinning and an unthinned first region. The thinned Poly layer second region includes multiple circular regions uniformly dispersed on the Poly layer.

[0102] The preparation method of the perovskite / TOPCon stacked cell of the embodiment is the same as that of Embodiment 1.

[0103] The top cell and the bottom cell are connected by a local TCO interconnection layer, which reduces the damage caused by magnetron sputtering during deposition of the transparent conductive oxide, reduces the parasitic absorption of the TCO interconnection layer, and reduces the risk of short circuit.

[0104] Reducing the thickness of part of the polysilicon layer in the TOPCon bottom cell reduces parasitic absorption and improves optical loss.

[0105] Embodiment 3

[0106] A perovskite / TOPCon stacked cell includes a perovskite cell, a TCO interconnection layer, and a TOPCon bottom cell. Figure 1

[0107] The perovskite cell includes a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, and a second transport layer. In the first transport layer and the second transport layer, the first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0108] ​The TOPCon bottom cell structure includes a third transport layer (Poly layer), a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode. The third transport layer is partially thinned, forming a thinned second region and an unthinned first region. There is no TCO interconnect layer above the thinned second region. The area of ​​the thinned second region accounts for 40% of the total area of ​​the third transport layer (Poly layer). The thickness of the unthinned first region is 80 nm, and the thickness of the thinned second region is 40 nm.

[0109] The thickness of the TCO interconnect layer is 30nm.

[0110] The structure of the third transport layer is as follows: Figure 4 As shown, it includes a second region of discontinuously thinned Poly layer formed by thinning process and a first region of non-thinned Poly layer, with the first region of non-thinned Poly layer and the second region of thinned Poly layer arranged alternately.

[0111] The fabrication method of the perovskite / TOPCon tandem solar cell in this embodiment is the same as that in Embodiment 1.

[0112] The top and bottom cells are connected by a local TCO interconnect layer, which reduces magnetron sputtering damage during transparent conductive oxide deposition, reduces parasitic absorption of the TCO interconnect layer, and reduces the risk of short circuit.

[0113] Reducing the thickness of some polycrystalline silicon layers in TOPCon bottom cells reduces parasitic absorption and improves optical loss.

[0114] Example 4

[0115] A perovskite / TOPCon tandem solar cell, such as Figure 1 As shown, it includes a perovskite solar cell, a TCO interconnect layer, and a TOPCon bottom cell.

[0116] The perovskite solar cell includes: a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, and a second transport layer. The first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0117] The structure of the TOPCon bottom cell includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode, wherein the third transport layer is partially thinned to form a thinned Poly layer second region and a non-thinned non-thinned Poly layer first region, and wherein the thinned Poly layer second region is free of a TCO interconnection layer thereon. The area of the thinned Poly layer second region accounts for 20% of the total area of the third transport layer Poly layer, the thickness of the non-thinned Poly layer first region is 80 nm, and the thickness of the thinned Poly layer second region formed after thinning is 40 nm.

[0118] The thickness of the TCO interconnection layer is 70 nm.

[0119] The structure of the third transport layer is as shown in Figure 4 The structure of the third transport layer is as shown in

[0120] The embodiment also provides a preparation method of the perovskite / TOPCon stacked cell, and the embodiment 1 is specifically referred to.

[0121] Embodiment 5

[0122] A perovskite / TOPCon stacked cell includes a perovskite cell, a TCO interconnection layer, and a TOPCon bottom cell. Figure 1

[0123] The perovskite cell includes a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, and a second transport layer. In the first transport layer and the second transport layer, the first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0124] The structure of the TOPCon bottom cell includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode, wherein the third transport layer is partially thinned to form a thinned Poly layer second region and a non-thinned non-thinned Poly layer first region, and wherein the thinned Poly layer second region is free of a TCO interconnection layer thereon. The area of the thinned Poly layer second region accounts for 20% of the total area of the third transport layer Poly layer, the thickness of the non-thinned Poly layer first region is 80 nm, and the thickness of the thinned Poly layer second region formed after thinning is 40 nm.

[0125] The thickness of the TCO interconnection layer is 50 nm.

[0126] The structure of the third transport layer is as shown in Figure 4 ​As shown, including the discontinuous thinning Poly layer second region formed by thinning treatment and the non-thinning non-thinning Poly layer first region, the non-thinning Poly layer first region and the thinning Poly layer second region are arranged alternately.

[0127] The embodiment also provides a preparation method of the perovskite / TOPCon stacked cell.

[0128] Comparative Example 1

[0129] A perovskite / TOPCon stacked cell includes a perovskite cell, a TCO interconnection layer, and a TOPCon bottom cell.

[0130] The perovskite cell includes a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer, and a second transport layer. In the first transport layer and the second transport layer, the first transport layer is an electron transport layer, and the second transport layer is a hole transport layer.

[0131] The structure of the TOPCon bottom cell includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode. The third transport layer is partially thinned to form a thinning Poly layer second region and a non-thinning non-thinning Poly layer first region. The non-thinning non-thinning Poly layer first region and the thinning Poly layer second region are arranged alternately, and the TCO interconnection layer is arranged above the non-thinning non-thinning Poly layer first region and the thinning Poly layer second region. The area of the thinning Poly layer second region accounts for 40% of the total area of the third transport layer Poly layer. The thickness of the non-thinning non-thinning Poly layer first region is 80 nm, and the thickness of the thinning Poly layer second region formed after thinning is 40 nm.

[0132] The thickness of the TCO interconnection layer is 30 nm.

[0133] The structure of the third transport layer is as shown in Figure 4 As shown, including the discontinuous thinning Poly layer second region formed by thinning treatment and the non-thinning non-thinning Poly layer first region, the non-thinning Poly layer first region and the thinning Poly layer second region are arranged alternately.

[0134] The preparation method of the perovskite / TOPCon stacked cell of Comparative Example 1 is as described in Reference Example 1, but step 9 is changed to removing part of the Poly layer by front-side laser; and step 10 is changed to depositing ITO on the front side to prepare the TCO interconnection layer.

[0135] Comparative Example 2

[0136] A perovskite / TOPCon stacked cell includes a perovskite cell, a TCO interconnection layer, and a TOPCon bottom cell.

[0137] The perovskite battery comprises a top electrode, a TCO layer, a buffer layer, a first transport layer, a perovskite layer and a second transport layer.

[0138] The structure of the TOPCon bottom cell comprises a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer and a back electrode.

[0139] The perovskite / TOPCon stacked battery of Comparative Example 2 is not subjected to the thinning treatment of the third transport layer Poly layer, and is a normal perovskite TOPCon stacked battery structure, with an ITO thickness of 30 nm and a third transport layer Poly layer thickness of 80 nm.

[0140] Results detection

[0141] The electrical performance of the related examples and comparative examples is determined, and the specific detection method is as follows: under the simulated light source of AM1.5, the energy density of the light source is 100 mW / cm 2 , a Weixin solar cell IV tester 6821S is used to test the J-V curve of the battery, and four electrical parameters of open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and conversion efficiency (Eff) are obtained; wherein, the conversion efficiency is determined by the open circuit voltage, short circuit current density and fill factor, and the calculation method is Eff = Voc Jsc FF / Pin, wherein Pin represents the incident light energy, and the Pin value is 100 mw / cm 2 .

[0142] The determination results are shown in Table 1 as follows:

[0143] Table 1

[0144]

[0145] The top cell and the bottom cell are connected by a local TCO interconnection layer, which reduces the damage of magnetron sputtering during deposition of the transparent conductive oxide, reduces the parasitic absorption of the TCO interconnection layer, reduces the short circuit current, and thus reduces the risk of short circuit.

[0146] As can be seen from the data in Table 1, the perovskite / TOPCon stacked battery of the present application reduces the thickness of part of the polysilicon layer in the TOPCon bottom cell, reduces the parasitic absorption, improves the optical loss, and improves the battery efficiency.

[0147] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A perovskite / TOPCon tandem cell, characterized in that, The third transport layer Poly layer in the TOPCon bottom cell is partially thinned to form a thinned Poly layer second area and a non-thinned Poly layer first area, the thinned Poly layer second area is free of a TCO interconnection layer, a perovskite cell and a TOPCon bottom cell are connected by a local TCO interconnection layer, The thickness of the non-thinned Poly layer first area is 70-100 nm, and the thickness of the thinned Poly layer second area is 40-60% of the original thickness. The area of the thinned Poly layer second area accounts for 20-40% of the total area of the third transport layer Poly layer.

2. The perovskite / TOPCon tandem cell of claim 1, wherein, The thinned Poly layer second area includes multiple discontinuous thinned Poly layer areas.

3. The perovskite / TOPCon tandem cell of claim 2, wherein, The non-thinned Poly layer first area and the thinned Poly layer second area are arranged alternately.

4. The perovskite / TOPCon tandem cell according to any one of claims 1-3, wherein, The thickness of the TCO interconnection layer is 30-70 nm.

5. The perovskite / TOPCon tandem cell according to any one of claims 1-3, wherein the perovskite / TOPCon tandem cell is a perovskite / Si tandem cell. The TOPCon bottom cell includes a third transport layer Poly layer, a tunneling layer, a silicon substrate, a fourth transport layer, a passivation layer, and a back electrode.

6. A method for preparing the perovskite / TOPCon tandem cell according to any one of claims 1-5, characterized in that, Comprising the following: S1: texturing the silicon substrate, preparing the fourth transport layer and the passivation layer on the back surface of the silicon wafer in sequence, back surface metallization, and preparing the back electrode; S2: preparing the tunneling layer, the third transport layer, the TCO interconnection layer, the second transport layer, the perovskite layer, the first transport layer, the buffer layer, and the TCO layer on the front surface of the silicon wafer in sequence, front surface metallization, and preparing the top electrode on the TCO layer.

7. A perovskite / TOPCon stacked cell according to any one of claims 1-5 for use in photovoltaic power generation.

8. A photovoltaic system characterized by, A battery assembly comprising the perovskite / TOPCon stacked cell according to any one of claims 1-5.

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