Three-terminal laminated solar cell, module and preparation method of three-terminal perovskite laminated solar cell

Abstract

The invention relates to a three-terminal laminated solar cell, a module and a preparation method of the three-terminal laminated solar cell, the cell comprises a bottom cell and a top cell, the bottom cell comprises a semiconductor substrate, the backlight side of the semiconductor substrate is provided with a first semiconductor region and a second semiconductor region which are opposite in conduction type, one of the first semiconductor region and the second semiconductor region has the same conductive type as the semiconductor substrate, the first electrode is conductively connected with the first semiconductor region, the second electrode is conductively connected with the second semiconductor region, and a third electrode is arranged on the backlight side of the semiconductor substrate; the top cell comprises a photoelectric conversion layer and a transparent conductive layer on a light receiving side; the conductive member extends along the lamination direction of the top cell and the bottom cell and conductively connects the transparent conductive layer and the third electrode. According to the invention, by utilizing the characteristic that the positive and negative wiring terminals of the back-contact bottom cell are both on the back, the top electrode is led to the back of the bottom cell through the conductive member, and the three wiring terminals of the cell are all arranged on the backlight side of the cell, so that the laminated cell interconnection structure is simplified.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaic cells, and more particularly, to a three-terminal stacked solar cell, a module, and a method for manufacturing a three-terminal perovskite stacked solar cell. Background Art

[0002] Against the backdrop of rising global energy demand and the dwindling supply of traditional energy sources, the development of new energy technologies has become extremely urgent. Solar energy, as a clean energy source, has received significant attention. Perovskite batteries, as a new force in the field of solar cells, offer hope for energy transformation. Traditional silicon-based solar cell technology is mature, but its limitations are becoming increasingly evident. The preparation process of silicon materials is complex, energy-consuming, and the cost cannot be reduced, which affects large-scale promotion. Moreover, according to the Shockley-Queisser theory, its theoretical limit efficiency is approximately 29.4%, and the current commercial efficiency is mostly in the range of 20-25%. Improving the efficiency further faces many challenges, such as low photon absorption efficiency of silicon materials for some photons and electron recombination inside the battery. The synthesis process of perovskite batteries is simple and can be prepared by methods such as solution spin coating, without the need for high-temperature and high-vacuum conditions, with low cost and energy consumption. Its raw materials are widely available, and the main components have rich reserves and low prices, providing a basis for large-scale production.

[0003] Currently, through the structural design of stacked solar cells composed of materials with different optical bandgaps, the spectral range of solar spectrum absorption and utilization by the battery can be comprehensively broadened, thereby enabling the battery efficiency to break through the Shockley-Queisser theoretical limit.

[0004] Stacked cells can be divided into two-terminal stacked cells, three-terminal stacked cells, and four-terminal stacked cells. Two-terminal stacked cells have two terminals, and their top cell and bottom cell adopt a current matching design. Two-terminal stacked cells require the bandgaps of the top cell and the bottom cell to match, which limits the selection of battery materials. Even if the bandgaps of the top cell and the bottom cell are precisely matched, when working outdoors, due to the change of the solar spectrum, there is still a situation where the currents of the top cell and the bottom cell do not match, resulting in current mismatch losses. In four-terminal stacked cells, the top cell and the bottom cell are independent of each other, and each has its own two terminals. Therefore, the top cell and the bottom cell can work independently in their respective optimal states. However, the top cell and the bottom cell of four-terminal stacked cells need to be processed, contacted, and connected separately, which increases the manufacturing workload, and the occlusion caused by a large number of terminals affects the light absorption of the battery.

[0005] In this field, three-terminal tandem cells have been developed. In addition to the top electrode at the top of the top cell and the bottom electrode at the bottom of the bottom cell, a three-terminal tandem cell also has an additional base electrode. The base electrode and the top electrode serve as the positive and negative electrodes of the top cell, and the base electrode and the bottom electrode serve as the positive and negative electrodes of the bottom cell. The three-terminal tandem cell can significantly reduce the loss caused by current mismatch. Compared with the four-terminal tandem cell, the interconnection within the module is simpler and the optical shielding of the wiring terminals is reduced. However, the wiring terminals of the existing three-terminal tandem cells are arranged on different sides, and the cell interconnection structure within the module is still complex. Summary of the Invention

[0006] To solve at least one problem of the prior art, the present disclosure provides a three-terminal tandem solar cell, a module, and a preparation method of a three-terminal perovskite tandem solar cell.

[0007] To achieve the above object, in the first aspect of the present disclosure, a three-terminal tandem solar cell is provided, which includes: A bottom cell, which includes a semiconductor substrate. On the backlight side of the semiconductor substrate, there are a first semiconductor region, a first electrode, a second semiconductor region, and a second electrode. The conduction types of the first semiconductor region and the second semiconductor region are opposite; the conduction type of the first semiconductor region is the same as that of the semiconductor substrate, or the conduction type of the second semiconductor region is the same as that of the semiconductor substrate; the first electrode is conductively connected to the first semiconductor region, the second electrode is conductively connected to the second semiconductor region, and a third electrode is further provided on the backlight side of the semiconductor substrate. The first electrode, the second electrode, and the third electrode are electrically isolated from each other; A top cell, which is stacked on the light-receiving side of the bottom cell. The top cell includes a photoelectric conversion layer and a transparent conductive layer provided on the light-receiving side of the photoelectric conversion layer for collecting charges from the photoelectric conversion layer; and, A conductive member, which extends along the stacking direction of the top cell and the bottom cell. One end of the conductive member is conductively connected to the transparent conductive layer, and the other end is conductively connected to the third electrode.

[0008] Optionally, the orthographic projection of the conductive member on the semiconductor substrate falls within the orthographic projection of the third electrode on the semiconductor substrate.

[0009] Optionally, the conductive member is arranged in a through hole that penetrates the three-terminal tandem solar cell along the stacking direction; and / or, the conductive member bypasses the side of the three-terminal tandem solar cell along the stacking direction.

[0010] Optionally, there is an isolation region between the first semiconductor region and the second semiconductor region on the backlight side of the bottom cell. The third electrode is disposed in the isolation region. A through hole penetrating the bottom cell and the top cell is correspondingly provided in the isolation region, and a conductive member is provided in the through hole.

[0011] Optionally, along a direction perpendicular to the stacking direction of the top cell and the bottom cell, the distance from the third electrode to the edge of the isolation region is 50 - 150 μm, and / or the width of the isolation region is 120 - 350 μm.

[0012] Optionally, there is an edge region on the backlight side edge of the bottom cell where the first semiconductor region and the second semiconductor region are not provided. The third electrode is provided in the edge region. A through hole penetrating the three-terminal stacked solar cell is provided in the edge region, and a conductive member is disposed in the through hole and is electrically connected to the third electrode in the edge region; and / or, the backlight side of the bottom cell includes a segmented region extending from one side to the other side. The first semiconductor region and the second semiconductor region are not provided in the segmented region. Two third electrodes and two through holes penetrating the three-terminal stacked solar cell are provided in the width direction of the segmented region. A conductive member is disposed in the through hole and is electrically connected to the third electrode in the segmented region; and / or, there is an edge region on the backlight side edge of the bottom cell where the first semiconductor region and the second semiconductor region are not provided. The third electrode is provided in the edge region. A notch is provided on the side of the three-terminal stacked solar cell, and a conductive member is provided in the notch. The conductive member in the notch is electrically connected to the third electrode in the edge region.

[0013] Optionally, a fourth electrode is provided on the light-receiving side of the transparent conductive layer. The fourth electrode is electrically connected to the transparent conductive layer, and the conductive member is electrically connected to the fourth electrode. The orthographic projection of the conductive member on the transparent conductive layer falls within the orthographic projection of the fourth electrode on the transparent conductive layer.

[0014] Optionally, the photoelectric conversion layer includes a light absorption layer, a first charge transport layer disposed on the light-receiving side of the light absorption layer, and a second charge transport layer disposed on the backlight side of the light absorption layer. The transparent conductive layer is disposed on the light-receiving side of the first charge transport layer.

[0015] Optionally, the third electrode and the conductive member are respectively electrically insulated from the bottom cell, and the conductive member is at least electrically insulated from the light absorption layer and the second charge transport layer.

[0016] In some embodiments, a first passivation layer is respectively provided between the first semiconductor region and the second semiconductor region and the semiconductor substrate; a second passivation layer is provided between the third electrode and the semiconductor substrate, and a dielectric layer is provided on the inner wall of the through hole; Optionally, the first passivation layer includes one or more layers of silicon oxide, silicon nitride, and intrinsic amorphous silicon; Optionally, the second passivation layer includes one or more layers of silicon oxide, silicon nitride, and silicon oxynitride; Optionally, the dielectric layer includes one layer or at least two layers of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, etc.

[0017] Optionally, the light absorption layer includes a perovskite thin film.

[0018] Optionally, an intermediate layer of a conductive type is provided between the semiconductor substrate and the top cell.

[0019] The second aspect of the present disclosure provides a three-terminal stacked solar cell module, which includes the three-terminal stacked solar cell of any one of the foregoing.

[0020] The third aspect of the present disclosure provides a method for preparing a three-terminal perovskite stacked solar cell, the method including: preparing a bottom cell, where the bottom cell includes a semiconductor substrate, a first semiconductor region, a first electrode, a second semiconductor region, and a second electrode are provided on the backlight side of the semiconductor substrate, and the conductive types of the first semiconductor region and the second semiconductor region are opposite; the conductive type of the first semiconductor region is the same as that of the semiconductor substrate, or the conductive type of the second semiconductor region is the same as that of the semiconductor substrate, the first electrode is conductively connected to the first semiconductor region, and the second electrode is conductively connected to the second semiconductor region; forming an intermediate layer of a conductive type on the light-receiving side of the semiconductor substrate; forming a second charge transport layer on the light-receiving side of the intermediate layer; forming a light absorption layer on the light-receiving side of the second charge transport layer, the light absorption layer including a perovskite thin film; forming a first charge transport layer on the light-receiving side of the light absorption layer; forming a transparent conductive layer on the light-receiving side of the first charge transport layer to obtain a stacked structure cell; forming a through hole penetrating the stacked structure cell; forming a dielectric layer in the through hole; forming a conductive member in the through hole, forming a third electrode conductively connected to the conductive member on the backlight side of the bottom cell, and forming a fourth electrode conductively connected to the conductive member on the transparent conductive layer.

[0021] Through the above technical solutions, the present disclosure uses a back-contact cell as the bottom cell for the three-terminal stacked solar cell. By utilizing the feature that both the positive and negative connection terminals of the back-contact cell are on the back, the top electrode of the top cell is led to the back of the bottom cell through a conductive member, so that the three connection terminals of the three-terminal stacked solar cell are all arranged on the backlight side of the cell. When interconnecting the stacked cells to prepare a cell module, the three connection terminals are all arranged on the backlight side of the stacked cells, which helps to simplify the interconnection structure of the stacked cells.

[0022] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation part. Description of the Drawings

[0023] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. They are used to explain the present disclosure together with the following specific implementation manners, but do not constitute a limitation to the present disclosure. In the drawings: Figure 1 It is a schematic diagram of a three-terminal stacked solar cell according to the present disclosure.

[0024] Figure 2 It is a schematic diagram of another three-terminal stacked solar cell according to the present disclosure.

[0025] Figure 3 It is a schematic diagram of another three-terminal stacked solar cell according to the present disclosure.

[0026] Description of reference numerals 11 Semiconductor substrate; 12 First semiconductor region; 13 First electrode; 14 Second semiconductor region; 15 Second electrode; 16 Third electrode; 17 First passivation layer; 18 Second passivation layer; 19 Intermediate layer; 21 Light absorption layer; 22 First charge transport layer; 23 Second charge transport layer; 24 Transparent conductive layer; 25 Fourth electrode; 31 Conductive member; 32 Through hole; 33 Dielectric layer; B Bottom cell; T Top cell. Detailed implementation manners

[0027] The following will describe in detail the specific implementation manners of the present disclosure with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for the purpose of illustration and explanation of the present disclosure, and are not used to limit the present disclosure.

[0028] In the present disclosure, unless otherwise stated, the orientation terms such as "upper, lower" generally refer to the upper and lower of the device in the normal use state. For example, referring to Figure 1 the drawing direction, "inner, outer" refers to relative to the contour of the device. In addition, the terms "first, second, third, fourth" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first, second, third, fourth" may explicitly or implicitly include one or more of such features. In the description of the present disclosure, "a plurality" means two or more, unless otherwise specifically defined.

[0029] As Figure 1 shown, the first aspect of the present disclosure provides a three-terminal stacked solar cell, and the three-terminal stacked solar cell includes: Bottom cell B, the bottom cell B includes a semiconductor substrate 11, a first semiconductor region 12, a first electrode 13, a second semiconductor region 14, and a second electrode 15 are provided on the backlight side of the semiconductor substrate 11; the conduction types of the first semiconductor region 12 and the second semiconductor region 14 are opposite; the conduction type of the first semiconductor region 12 is the same as that of the semiconductor substrate 11, or the conduction type of the second semiconductor region 14 is the same as that of the semiconductor substrate 11; the first electrode 13 is conductively connected to the first semiconductor region 12, the second electrode 15 is conductively connected to the second semiconductor region 14, and a third electrode 16 is further provided on the backlight side of the semiconductor substrate 11, and the first electrode 13, the second electrode 15, and the third electrode 16 are electrically isolated from each other; Top cell T, the top cell T is stacked on the light-receiving side of the bottom cell B, the top cell T includes a photoelectric conversion layer and a transparent conductive layer 24 provided on the light-receiving side of the photoelectric conversion layer for collecting charges from the photoelectric conversion layer; and, Conductive member 31, the conductive member 31 extends along the stacking direction of the top cell T and the bottom cell B, one end of the conductive member 31 is conductively connected to the transparent conductive layer 24, and the other end is conductively connected to the third electrode 16.

[0030] The bottom cell B of the present disclosure is a back-contact solar cell, and the PN junction, the positive electrode, and the negative electrode are all provided on the backlight side of the semiconductor substrate. Since the conductive member 31 is electrically connected to the transparent conductive layer 24 on the light-receiving side, and the positive electrode and the negative electrode of the bottom cell B are both provided on the backlight side of the bottom cell B, the top electrode of the top cell T is led to the backlight side of the bottom cell B through the conductive member 31. Therefore, the conductive member 31 can transmit the current of the transparent electrode to the backlight side of the cell, so that the three wiring terminals (the first electrode 13, the second electrode 15, and the third electrode 16) of the three-terminal stacked solar cell are all provided on the backlight side of the solar cell, which can simplify the interconnection structure of the three-terminal stacked solar cell module.

[0031] The light-receiving surface of the bottom cell B has no grid lines, which avoids the shadow occlusion phenomenon caused by the grid lines of the cell in the sun, can broaden the spectral response to a greater extent, and improve the efficiency of the cell; on the other hand, the bottom cell B has the natural advantages of a three-terminal tandem solar cell. Combined with the conductive member 31, it can quickly lead the carriers on the light-receiving surface of the top cell T to the back of the cell. Compared with a four-terminal cell, the three-terminal tandem solar cell of the present disclosure can reduce the number of electrodes, simplify the cell structure, reduce the material cost and preparation difficulty of the cell; and compared with a two-terminal cell, the three-terminal tandem solar cell of the present disclosure does not need to consider the harsh preparation conditions of two materials in the same process system, can reduce the process difficulty and production cost, and can also avoid the problem of series current matching of the two-terminal cell. In addition, the three-terminal tandem solar cell of the present disclosure allows for a more flexible design of the electrical connection between the bottom cell B and the top cell T, can better match the current output of the two cells under different light conditions, and improve the utilization efficiency of different spectra.

[0032] When interconnecting multiple tandem solar cells of the present disclosure with an interconnecting member (such as a solder ribbon) to prepare a solar cell module, since the three connection terminals of the tandem solar cell are all arranged on the back, there is no need to arrange an interconnecting member on the light-receiving side of the three-terminal tandem solar cell. The interconnecting member does not need to be bent at the edge of the cell, reducing the risk of edge cracking of the cell, and there is no occlusion of the interconnecting member on the light-receiving side of the cell, which can improve the photoelectric conversion efficiency of the tandem solar cell.

[0033] In some embodiments, the orthographic projection of the conductive member 31 on the semiconductor substrate 11 falls within the orthographic projection of the third electrode 16 on the semiconductor substrate 11. Since the orthographic projection of the conductive member 31 on the semiconductor substrate 11 falls within the orthographic projection of the third electrode 16 on the semiconductor substrate 11, the third electrode 16 has a wider width than the conductive member 31. Compared with directly connecting the conductive member 31 to the interconnecting member, by providing a wider third electrode 16 at the end of the conductive member 31 in the present disclosure, the reliability of the conductive connection between the conductive member 31 and the interconnecting member (such as a solder ribbon) can be improved. Providing a wider third electrode 16 at the end of the conductive member 31 helps to improve the mechanical bonding force between the connection terminal (top electrode) of the top cell T and the three-terminal tandem solar cell. When the currents of multiple conductive members 31 converge to the third electrode 16, the wider third electrode 16 helps to reduce the resistance loss.

[0034] In some embodiments, the conductive member 31 is disposed in the through-hole 32 that penetrates the three-terminal stacked solar cell along the stacking direction. Specifically, a through-hole 32 that penetrates the top cell T and the bottom cell B is provided along the stacking direction of the top cell T and the bottom cell B, and the conductive member 31 extends within the through-hole 32. The conductive member 31 can extend from one end of the through-hole 32 near the light-receiving side to the other end of the through-hole 32 near the backlight side. One end of the conductive member 31 near the light-receiving side is electrically connected to the transparent conductive layer 24, and the other end is electrically connected to the third electrode 16 on the backlight side of the bottom cell B. The conductive member 31 conducts the carriers transmitted by the transparent conductive layer 24 to the third electrode 16 on the backlight side. By disposing the conductive member 31 in the through-hole 32, the through-hole 32 that penetrates the top cell T and the bottom cell B can be formed in the middle of the three-terminal stacked solar cell away from the edge, which helps to shorten the carrier transmission distance in the middle region of the top cell T and improve the carrier collection ability in the middle of the top cell T.

[0035] Exemplarily, there is an isolation region I between the first semiconductor region 12 and the second semiconductor region 14 on the backlight side of the bottom cell B. The third electrode 16 is disposed in the isolation region I, and the through-hole 32 that penetrates the bottom cell B and the top cell T is correspondingly provided in the isolation region I. The conductive member 31 is disposed within the through-hole 32. The isolation region I between the first semiconductor region 12 and the second semiconductor region 14 can physically isolate the first semiconductor region 12 and the second semiconductor region 14, preventing leakage due to contact between the first semiconductor region 12 and the second semiconductor region 14. The third electrode 16 is disposed in the isolation region I and is isolated from the first semiconductor region 12, the second semiconductor region 14, the first electrode 13, and the second electrode 15 respectively. In this way, the first electrode 13, the second electrode 15, and the third electrode 16 of the three-terminal stacked solar cell are independent terminals respectively, preventing internal leakage of the three-terminal stacked solar cell due to their contact.

[0036] Furthermore, the isolation region I has a texture structure. The texture structure can be a positive pyramid-shaped matte structure, an inverted pyramid-shaped matte structure, a pyramid-shaped matte with a flattened top, or a wormhole-shaped matte structure, etc. The texture structure of the isolation region I can improve the light absorption of the battery and increase the photoelectric conversion efficiency of the three-terminal stacked solar cell.

[0037] Further, along the direction perpendicular to the stacking direction of the top cell T and the bottom cell B, the distance W1 from the third electrode 16 to the edge of the isolation region is not less than 50 μm. Exemplarily, the distance W1 from the third electrode 16 to the edge of the isolation region is 50 - 150 μm. A sufficiently large distance from the third electrode 16 to the edge of the isolation region helps with the electrical isolation between the third electrode 16 and the first semiconductor region 12 and the second semiconductor region 14, expands the process window, and reduces the manufacturing difficulty. There is a third electrode 16 provided along the width direction of the isolation region I. The third electrode 16 maintains an appropriate distance from the edge of the isolation region I, so as to maintain a good isolation effect between the third electrode 16 and the first semiconductor region 12 and the second semiconductor region 14. The width W2 of the isolation region I can be 120 - 350 μm. Preferably, the width W2 of the isolation region I is 120 - 150 μm. When the width of the isolation region I is too small, it will result in too small a distance from the third electrode 16 to the edge of the isolation region I, increasing the manufacturing difficulty of the third electrode 16 and the risk of contact with the first semiconductor region 12 and / or the second semiconductor region 14. When the width of the isolation region I is too large, it will reduce the area of the PN junction, increase the diffusion distance of the carriers in the bottom cell B, and reduce the carrier collection efficiency. Setting the width of the isolation region I within a reasonable range can not only keep an appropriate safety distance between the third electrode 16 and the edge of the isolation region I, but also take into account the carrier collection efficiency.

[0038] In some embodiments, as Figure 2 shown, the backlight side edge of the bottom cell B has an edge region II where the first semiconductor region 12 and the second semiconductor region 14 are not provided. The third electrode 16 is provided in the edge region II. The edge region II has a through hole 32 penetrating the three-terminal stacked solar cell, and a conductive member 31 is disposed in the through hole 32 and is electrically connected to the third electrode 16 in the edge region II.

[0039] Optionally, the edge region II has a texture structure. The texture structure can be a positive pyramid-shaped matte structure, an inverted pyramid-shaped matte structure, a pyramid-shaped matte with a flattened top, or a wormhole-shaped matte structure, etc. The texture structure of the edge region II can improve the light absorption of the cell and increase the photoelectric conversion efficiency of the three-terminal stacked solar cell.

[0040] Optionally, the backlight side of the bottom cell B includes a segmented area III extending from one side to the other side, where the first semiconductor area 12 and the second semiconductor area 14 are not provided. In the width direction of the segmented area III, two spaced third electrodes 16 and through holes 32 corresponding to the third electrodes 16 are provided in the segmented area III. A conductive member 31 is disposed in the through holes 32 and is electrically connected to the third electrodes 16 in the segmented area III. When the three-terminal stacked solar cell is cut along the gap between the two third electrodes 16, the third electrodes 16 and the conductive member 31 in the segmented area III can help collect the carriers at the edge of the segmented cell.

[0041] Optionally, the segmented area III has a texture structure. The texture structure can be a positive pyramid-shaped suede structure, an inverted pyramid-shaped suede structure, a pyramid-shaped suede with a flattened top, or a wormhole-shaped suede structure, etc. The texture structure of the segmented area III can improve the light absorption of the cell and increase the photoelectric conversion efficiency of the three-terminal stacked solar cell.

[0042] In some embodiments, as Figure 3 shown, the conductive member 31 bypasses the side of the three-terminal stacked solar cell along the stacking direction. For example, the edge area II of the backlight side of the bottom cell B where the first semiconductor area 12 and the second semiconductor area 14 are not provided is provided with a third electrode 16. A notch is provided on the side of the three-terminal stacked solar cell, and a conductive member 31 is provided in the notch. The conductive member in the notch is electrically connected to the third electrode 16 in the edge area II.

[0043] In some embodiments, a fourth electrode 25 is provided on the light-receiving side of the transparent conductive layer 24. The fourth electrode 25 is electrically connected to the transparent conductive layer 24, and the conductive member 31 is electrically connected to the fourth electrode 25. In this way, charges are longitudinally and laterally transmitted in the transparent conductive layer 24 to the fourth electrode 25, and then transmitted to the conductive member 31 through the fourth electrode 25, and are guided by the conductive member 31 to the third electrode 16 on the backlight side. Since the fourth electrode 25 is provided on the light-receiving side of the transparent conductive layer 24, a pattern extending in a direction away from the conductive member 31 can be provided for the fourth electrode 25, which is convenient for collecting the current at a position farther from the conductive member 31.

[0044] Furthermore, the orthographic projection of the conductive member 31 on the transparent conductive layer 24 falls within the orthographic projection of the fourth electrode 25 on the transparent conductive layer 24. Since the orthographic projection of the conductive member 31 on the transparent conductive layer 24 falls within the orthographic projection of the fourth electrode 25 on the transparent conductive layer 24, the fourth electrode 25 has a wider width than the conductive member 31. Providing a wider fourth electrode 25 at the end of the conductive member 31 helps to increase the ability to collect current from the transparent conductive layer 24 and improve the charge collection efficiency from the transparent conductive layer 24.

[0045] In some embodiments, the conductive member 31, the fourth electrode 25, and the third electrode 16 can independently be a silver electrode, a copper electrode, an aluminum electrode, or a nickel electrode.

[0046] In some embodiments, the bandgap of the top cell T is greater than that of the bottom cell B. For example, the bandgap of the top cell T can be 1.65 - 1.7 eV, and the bandgap of the bottom cell B can be 1.1 - 1.3 eV. Since the bandgap of the top cell T is greater than that of the bottom cell B, the top cell T can absorb short-wavelength light with higher energy, and the bottom cell B can absorb long-wavelength light with lower energy, thereby improving the utilization rate of the solar spectrum by the three-terminal tandem solar cell. Optionally, the top cell T can be a perovskite thin-film cell, an organic thin-film solar cell, a copper indium gallium selenide thin-film solar cell, or a cadmium telluride thin-film solar cell. The top cell T is preferably a perovskite thin-film cell. The bottom cell B can be a monocrystalline silicon solar cell.

[0047] In some embodiments, the bottom cell B includes a semiconductor substrate 11. The material of the semiconductor substrate 11 can be materials such as silicon, germanium, or gallium arsenide. In a preferred embodiment, the semiconductor substrate 11 is a silicon semiconductor. The conductivity type of the semiconductor substrate 11 can be p-type or n-type. In a preferred embodiment, the semiconductor substrate 11 is an n-type semiconductor. The n-type semiconductor has a longer carrier lifetime, which is beneficial to the photoelectric conversion efficiency.

[0048] Exemplarily, one of the first semiconductor region 12 and the second semiconductor region 14 has the same conductivity type as the semiconductor substrate 11, and the other two of the first semiconductor region 12 and the second semiconductor region 14 have the opposite conductivity type to the semiconductor substrate 11. For example, the first semiconductor region 12 has the same conductivity type as the semiconductor substrate, and the second semiconductor region 14 has the opposite conductivity type to the semiconductor substrate. That is, when the semiconductor substrate is an n-type semiconductor, the first semiconductor region 12 is an n-type semiconductor, and the second semiconductor region 14 is a p-type semiconductor. When the semiconductor substrate is a p-type semiconductor, the first semiconductor region 12 is a p-type semiconductor, and the second semiconductor region 14 is an n-type semiconductor. The n-type semiconductor can be prepared by doping a pentavalent element such as phosphorus, arsenic, or antimony into the semiconductor, and the p-type semiconductor can be prepared by doping a trivalent element such as boron or aluminum into the semiconductor. Among them, the semiconductor materials of the first semiconductor region 12 and the second semiconductor region 14 can independently be silicon, gallium arsenide, etc. In a preferred embodiment, the materials of the first semiconductor region 12 and the second semiconductor region 14 are silicon materials, the n-type doping element is phosphorus, and the p-type doping element is boron.

[0049] Exemplarily, a first passivation layer 17 is inserted between the first semiconductor region 12 and the second semiconductor region 14 and the semiconductor substrate 11, respectively. The thickness of the first passivation layer 17 can be 0.5 - 5.0 nm. Further, the thickness of the first passivation layer 17 can be 0.5 - 2.5 nm. The first passivation layer 17 with such a thickness has a good tunneling effect and can selectively pass carriers. The first passivation layer 17 can be selected from one or more of silicon oxide, silicon nitride, and intrinsic amorphous silicon.

[0050] Exemplarily, the first semiconductor region 12 and the second semiconductor region 14 are doped polysilicon layers with opposite conduction types, and the first passivation layer 17 is silicon oxide. Passivation contact structures are respectively formed in the first semiconductor region 12 and the second semiconductor region 14, having a good passivation effect.

[0051] Exemplarily, the first semiconductor region 12 and the second semiconductor region 14 are doped amorphous silicon layers with opposite conduction types, and the first passivation layer 17 is intrinsic amorphous silicon. Heterojunction structures are respectively formed in the first semiconductor region 12 and the second semiconductor region 14, achieving a good passivation effect.

[0052] Exemplarily, the first semiconductor region 12 and the second semiconductor region 14 are doped polysilicon and doped amorphous silicon with opposite conduction types. The first passivation layer 17 corresponding to the doped polysilicon is silicon oxide, and the first passivation layer 17 corresponding to the doped amorphous silicon is intrinsic amorphous silicon. Hybrid passivation structures including passivation contact structures and heterojunction structures are respectively formed in the first semiconductor region 12 and the second semiconductor region 14 to improve the passivation effect.

[0053] In some embodiments, the first semiconductor region 12 and the second semiconductor region 14 can be alternately arranged at intervals. This can shorten the transmission distance of charges from the semiconductor substrate 11 to the first semiconductor region 12 and the second semiconductor region 14.

[0054] In some embodiments, the top cell T includes a photoelectric conversion layer and a transparent conductive layer 24 disposed on the light-receiving side of the photoelectric conversion layer for collecting charges from the photoelectric conversion layer. The photoelectric conversion layer includes a light absorption layer 21, a first charge transport layer 22 disposed on the light-receiving side of the light absorption layer 21, and a second charge transport layer 23 disposed on the backlight side of the light absorption layer 21. The transparent conductive layer 24 is disposed on the light-receiving side of the first charge transport layer 22. The first charge transport layer 22 can extract and transport the first charge from the light absorption layer 21, and the second charge transport layer 23 can extract and transport the second charge from the light absorption layer 21, where the first charge is an electron and the second charge is a hole, or the first charge is a hole and the second charge is an electron. The light absorption layer 21 absorbs photon energy to generate excitons.

[0055] For example, the light absorption layer 21 includes a perovskite thin film. The first charge transport layer 22 can be an electron transport layer, and the second charge transport layer 23 can be a hole transport layer. Alternatively, the first charge transport layer 22 can be a hole transport layer, and the second charge transport layer 23 can be an electron transport layer.

[0056] Optionally, the general formula of the material of the perovskite thin film can be ABX3, where A is a monovalent cation, B is a divalent cation, and X is a monovalent anion. A includes, but is not limited to, one or more of cesium ions, rubidium ions, methylamine ions, dimethylamine ions, and formamidinium ions. B includes, but is not limited to, one or more of lead ions, copper ions, zinc ions, gallium ions, tin ions, and calcium ions. X includes, but is not limited to, one or more of iodide ions, bromide ions, chloride ions, fluoride ions, thiocyanate ions, tetrafluoroborate ions, and hexafluorophosphate ions.

[0057] Optionally, the electron transport layer can include any one or a combination of at least two of C60, fullerene derivatives, tin oxide, titanium oxide, zinc oxide, cadmium sulfide, indium sesquioxide, and tungsten oxide.

[0058] Optionally, the hole transport layer can include any one or a combination of at least two of copper phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, nickel oxide, vanadium oxide, molybdenum oxide, copper sulfide, cuprous thiocyanate, copper oxide, cuprous oxide, cobalt oxide, poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (abbreviated as PTAA), poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (abbreviated as PEDOT:PSS), N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine (abbreviated as Poly-TPD), 2,2',7,7'-tetrakis(N,N-di-p-methoxyaniline)-9,9'-spirobifluorene (abbreviated as Spiro-MeOTAD).

[0059] Optionally, the transparent conductive layer 24 can include one layer or at least two layers of indium tin oxide (ITO) substrate, fluorine-doped tin oxide (FTO) substrate, or indium zinc oxide (IZO) substrate.

[0060] In some embodiments, the third electrode 16 and the conductive member 31 are electrically insulated from the bottom cell B, respectively, and the conductive member 31 is at least electrically insulated from the light absorption layer 21 and the second charge transport layer 23.

[0061] Exemplarily, a second passivation layer 18 is provided between the third electrode 16 and the semiconductor substrate 11, and the conductive member 31 passes through the passivation layer and is electrically connected to the third electrode 16. On the one hand, the second passivation layer 18 can passivate the semiconductor substrate 11 to reduce the surface recombination of carriers on the semiconductor substrate 11. On the other hand, it can prevent the third electrode 16 from directly contacting the semiconductor substrate 11, so as to maintain the independence between the terminals. Optionally, the second passivation layer 18 includes one or more layers of silicon oxide, silicon nitride, or silicon oxynitride.

[0062] Furthermore, the second passivation layer 18 can also cover the first semiconductor region 12, the second semiconductor region 14, and the semiconductor substrate 11 corresponding to the isolation region I to passivate the semiconductor surface defects and reduce the surface recombination of carriers.

[0063] Exemplarily, a dielectric layer 33 is provided on the inner wall of the through hole 32. The dielectric layer 33 can surround the inner wall of the through hole 32. The dielectric layer 33 has electrical insulation properties and can isolate the conductive member 31 from at least part of the top cell T and the bottom cell B to prevent internal leakage in the three-terminal stacked solar cell. Exemplarily, the material of the dielectric layer 33 can be one or at least two or more layers of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0064] In some embodiments, a conductive intermediate layer 19 is provided between the semiconductor substrate 11 and the top cell T. The intermediate layer 19 can be an n-type conductive silicon-based thin film, a p-type conductive silicon-based thin film, or a transparent conductive thin film. The through hole 32 penetrates the intermediate layer 19, and the inner wall of the through hole 32 of the intermediate layer 19 has a dielectric layer 33 to prevent the conductive member 31 from directly contacting the intermediate layer 19.

[0065] The second aspect of the present disclosure provides a three-terminal stacked solar cell module, which includes the aforementioned three-terminal stacked solar cell.

[0066] The third aspect of the present disclosure provides a method for preparing the three-terminal perovskite-silicon stacked solar cell described in the first aspect, and the method includes the following steps: Preparing a bottom cell B, where the bottom cell B includes a semiconductor substrate 11, a first semiconductor region 12, a first electrode 13, a second semiconductor region 14, and a second electrode 15 are provided on the backlight side of the semiconductor substrate 11, and the conductive types of the first semiconductor region 12 and the second semiconductor region 14 are opposite; the conductive type of the first semiconductor region 12 is the same as that of the semiconductor substrate 11, or the conductive type of the second semiconductor region 14 is the same as that of the semiconductor substrate 11, the first electrode 13 is electrically connected to the first semiconductor region 12, and the second electrode 15 is electrically connected to the second semiconductor region 14; Forming a conductive intermediate layer 19 on the light-receiving side of the semiconductor substrate 11; A second charge transport layer 23 is formed on the light-receiving side of the intermediate layer 19; A light absorption layer 21 is formed on the light-receiving side of the second charge transport layer 23, and the light absorption layer 21 includes a perovskite thin film; A first charge transport layer 22 is formed on the light-receiving side of the light absorption layer 21; A transparent conductive layer 24 is formed on the light-receiving side of the first charge transport layer 22 to obtain a stacked structure battery; A through hole 32 penetrating the stacked structure battery is formed; A dielectric layer 33 is formed in the through hole 32; A conductive member 31 is formed in the through hole 32, a third electrode 16 electrically connected to the conductive member 31 is formed on the backlight side of the bottom cell B, and a fourth electrode 25 electrically connected to the conductive member 31 is formed on the transparent conductive layer 24.

[0067] In some embodiments, the intermediate layer 19 may be one or two layers such as an ITO substrate, an IZO substrate, an IWO substrate, etc., and is prepared by magnetron sputtering (PVD) method, with a thickness of 5 nm or 15 - 20 nm, preferably 5 nm.

[0068] In some embodiments, the second charge transport layer 23 may be an electron transport layer, including two layers of a C60 film layer and a tin dioxide (SnO2) film layer. The C60 film layer is prepared by vacuum evaporation method, with a thickness of 10 - 15 nm, and the tin dioxide film layer is prepared by atomic layer deposition (ALD) process, with a thickness of 15 - 30 nm.

[0069] In some embodiments, the material of the perovskite thin film may be Cs 0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3, and the preparation process may be a solution coating method (spin coating or slot coating or spraying, etc.), and the thickness of the perovskite thin film may be 500 - 700 nm.

[0070] In some embodiments, the first charge transport layer 22 is a hole transport layer, including nickel oxide and a SAM self-assembled layer. The nickel oxide layer can be prepared by magnetron sputtering or solution coating method, with a thickness range of 10 - 50 nm, and the SAM self-assembled layer is deposited above the nickel oxide and can be deposited by solution coating processes such as spin coating, spraying, etc., with a thickness range of 1 - 5 nm.

[0071] In some embodiments, the material of the transparent conductive layer 24 can be selected from an ITO substrate, an IWO substrate, an IXO substrate, an IZO substrate, an ICO substrate, etc., and the transparent conductive layer 24 can be prepared by magnetron sputtering process, with a film layer thickness of 80 - 100 nm.

[0072] In some embodiments, the third electrode 16 and / or the fourth electrode 25 may be made of pure silver or low-temperature silver paste, and can be prepared by vacuum evaporation, magnetron sputtering or screen printing. Among them, the film thickness of vacuum evaporation or magnetron sputtering is 500-1000 nm, and the thickness of the electrode prepared by screen printing process is 15-30 μm.

[0073] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0074] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0075] In addition, any combination can be made between various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A three-terminal stacked solar cell, characterized in that: The three-terminal tandem solar cell comprises: A bottom battery (B), the bottom battery (B) comprising a semiconductor substrate (11), a first semiconductor region (12), a first electrode (13), a second semiconductor region (14) and a second electrode (15) being provided on the backlight side of the semiconductor substrate (11); the first semiconductor region (12) and the second semiconductor region (14) being of opposite conductivity types; the first semiconductor region (12) and the semiconductor substrate (11) being of the same conductivity type, or the second semiconductor region (14) and the semiconductor substrate (11) being of the same conductivity type; the first electrode (13) being conductively connected to the first semiconductor region (12), the second electrode (15) being conductively connected to the second semiconductor region (14), the backlight side of the semiconductor substrate (11) being further provided with a third electrode (16), the first electrode (13), the second electrode (15) and the third electrode (16) being electrically isolated from each other; A top cell (T), the top cell (T) being stacked on the light-receiving side of the bottom cell (B), the top cell (T) comprising a photoelectric conversion layer and a transparent conductive layer (24) disposed on the light-receiving side of the photoelectric conversion layer for collecting charges from the photoelectric conversion layer; and A conductive member (31), the conductive member (31) extending along the stacking direction of the top battery (T) and the bottom battery (B), one end of the conductive member (31) being conductively connected to the transparent conductive layer (24), and the other end of the conductive member (31) being conductively connected to the third electrode (16).

2. The three-terminal tandem solar cell according to claim 1, characterized in that: An orthographic projection of the conductive member (31) on the semiconductor substrate (11) falls within an orthographic projection of the third electrode (16) on the semiconductor substrate (11).

3. The three-terminal tandem solar cell according to claim 1, characterized in that: The conductive member (31) is arranged in a through hole (32) that penetrates the three-terminal stacked solar cell along the stacking direction; and / or, The conductive component (31) bypasses the side of the three-terminal stacked solar cell along the stacking direction.

4. The three-terminal tandem solar cell according to claim 3, characterized in that: An isolation region (I) is provided between the first semiconductor region (12) and the second semiconductor region (14) on the backlight side of the bottom battery (B), the third electrode (16) is arranged in the isolation region (I), and the isolation region (I) is provided with a through hole (32) penetrating the bottom battery (B) and the top battery (T), and the conductive component (31) is provided in the through hole (32).

5. The three-terminal tandem solar cell according to claim 4, characterized in that: Along a direction perpendicular to the stacking direction of the three-terminal stacked solar cell, the distance from the third electrode (16) to the edge of the isolation region (I) is 50-150 μm, and / or the width of the isolation region (I) is 120-350 μm.

6. The three-terminal tandem solar cell according to claim 3, characterized in that: The backlight side edge of the bottom cell (B) has an edge region (II) where the first semiconductor region (12) and the second semiconductor region (14) are not provided, the edge region (II) is provided with the third electrode (16), the edge region (II) has a through hole (32) that penetrates the three-terminal stacked solar cell, the conductive member (31) is arranged in the through hole (32) and is conductively connected to the third electrode (16) of the edge region (II); and / or, The backlight side of the bottom cell (B) comprises a slicing region (III) extending from one side to the other side, the slicing region (III) is not provided with the first semiconductor region (12) and the second semiconductor region (14), two third electrodes (16) and two through holes (32) penetrating the three-terminal stacked solar cell are provided in the width direction of the slicing region (III), the conductive member (31) is arranged in the through hole (32) and is conductively connected to the third electrode (16) of the slicing region (III); and / or, The backlight side edge of the bottom cell (B) has an edge region (II) where the first semiconductor region (12) and the second semiconductor region (14) are not provided, the edge region (II) is provided with the third electrode (16), a notch is provided on the side of the three-terminal stacked solar cell, the conductive component (31) is provided in the notch, and the conductive component (31) in the notch is conductively connected to the third electrode (16) of the edge region (II).

7. The three-terminal tandem solar cell according to claim 1, characterized in that: A fourth electrode (25) is provided on the light-receiving side of the transparent conductive layer (24); the fourth electrode (25) is conductively connected to the transparent conductive layer (24); the conductive component (31) is conductively connected to the fourth electrode (25); and the orthographic projection of the conductive component (31) on the transparent conductive layer (24) falls within the orthographic projection of the fourth electrode (25) on the transparent conductive layer (24).

8. The three-terminal tandem solar cell according to claim 3, characterized in that: The photoelectric conversion layer comprises a light absorbing layer (21), a first charge transport layer (22) arranged on the light receiving side of the light absorbing layer (21), and a second charge transport layer (23) arranged on the backlight side of the light absorbing layer (21), and the transparent conductive layer (24) is arranged on the light receiving side of the first charge transport layer (22).

9. The three-terminal tandem solar cell according to claim 8, characterized in that: The third electrode (16) and the conductive member (31) are respectively electrically insulated from the bottom cell (B), and the conductive member (31) is at least electrically insulated from the light absorbing layer (21) and the second charge transport layer (23).

10. The three-terminal tandem solar cell according to claim 9, characterized in that: The first semiconductor region (12) and the second semiconductor region (14) are respectively provided with a first passivation layer (17) between the semiconductor substrate (11); A second passivation layer (18) is provided between the third electrode (16) and the semiconductor substrate (11), and a dielectric layer (33) is provided on the inner wall of the through hole (32); Optionally, the first passivation layer (17) comprises one or more layers of silicon oxide, silicon nitride and intrinsic amorphous silicon; Optionally, the second passivation layer (18) comprises one or more layers of silicon oxide, silicon nitride and silicon oxynitride; Optionally, the dielectric layer (33) includes one layer or at least two layers of silicon oxide, aluminum oxide, silicon nitride and silicon oxynitride.

11. The three-terminal tandem solar cell according to claim 8, characterized in that: The light absorbing layer (21) comprises a perovskite thin film.

12. The three-terminal tandem solar cell according to claim 1, characterized in that: A conductive intermediate layer (19) is provided between the semiconductor substrate (11) and the top battery (T).

13. A three-terminal stacked solar cell module, characterized in that: The three-terminal stacked solar cell module comprises the three-terminal stacked solar cell according to any one of claims 1 to 12.

14. A method for preparing a three-terminal perovskite tandem solar cell, characterized in that: The method includes: A bottom battery (B) is prepared, wherein the bottom battery (B) comprises a semiconductor substrate (11), a first semiconductor region (12), a first electrode (13), a second semiconductor region (14) and a second electrode (15) are provided on the backlight side of the semiconductor substrate (11), the first semiconductor region (12) and the second semiconductor region (14) have opposite conductivity types; the first semiconductor region (12) and the semiconductor substrate (11) have the same conductivity type, or the second semiconductor region (14) and the semiconductor substrate (11) have the same conductivity type; the first electrode (13) is conductively connected to the first semiconductor region (12), and the second electrode (15) is conductively connected to the second semiconductor region (14); forming an intermediate layer (19) having a conductive type on the light-receiving side of the semiconductor substrate (11); forming a second charge transport layer (23) on the light-receiving side of the intermediate layer (19); forming a light absorbing layer (21) on the light receiving side of the second charge transport layer (23), wherein the light absorbing layer (21) comprises a perovskite thin film; forming a first charge transport layer (22) on the light receiving side of the light absorbing layer (21); forming a transparent conductive layer (24) on the light-receiving side of the first charge transport layer (22) to obtain a stacked structure battery; Forming a through hole (32) penetrating the stacked structure battery; forming a dielectric layer (33) in the through hole (32); A conductive member (31) is formed in the through hole (32), a third electrode (16) conductively connected to the conductive member (31) is formed on the backlight side of the bottom battery (B), and a fourth electrode (25) conductively connected to the conductive member (31) is formed on the transparent conductive layer (24).

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