Three-terminal back contact perovskite / CIGS laminated solar cell and application thereof

Abstract

The invention provides a three-end back contact perovskite / CIGS laminated solar cell and application thereof, and belongs to the field of laminated solar cells. According to the three-end back contact perovskite / CIGS laminated solar cell provided by the invention, the first metal electrode is arranged on the ITO transparent electrode blank area, so that the utilization rate of sunlight is improved to the maximum extent; the CIGS light absorption layer is arranged to be of an inverted L-shaped or 7-shaped structure, meanwhile, the side face of the passivation layer is attached to the inner side of the vertical portion of the CIGS light absorption layer, the buffer layer and the metal electrode can be completely and electrically isolated from the back field layer, use of transparent electrodes is reduced, optical parasitic absorption is further reduced, and the photoelectric conversion efficiency of the cell is improved. The photoelectric conversion utilization rate of the three-end back contact perovskite / CIGS laminated solar cell can reach 33.20%, and the three-end back contact perovskite / CIGS laminated solar cell has high photoelectric conversion efficiency, excellent flexible performance and good long-term stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laminated solar cells, in particular to a three-terminal back contact perovskite / CIGS laminated solar cell and application thereof. BACKGROUND

[0002] With the acceleration of global population growth and industrialization, the consumption of traditional fossil energy such as coal, oil and natural gas is rising, leading to the exhaustion of resources and the worsening of energy crisis. At the same time, the use of a large amount of fossil energy also causes serious environmental pollution and greenhouse gas emissions, which becomes an important inducement of global climate change. Solar energy is considered one of the most promising alternative energy sources due to its advantages of abundant resources, green and environmental protection and sustainable utilization. Solar cells, as the core device for directly converting light energy into electrical energy, have become the key focus of current research in terms of conversion efficiency, preparation cost and stability.

[0003] In recent years, perovskite solar cells have become the most promising material in the field of photovoltaics due to their excellent photoelectric performance, low-cost process and rapid efficiency improvement. At the same time, in order to further break through the upper limit of single-junction cells (Shockley-Queisser limit), laminated solar cells have emerged. Among them, perovskite / CIGS laminated solar cells have attracted much attention due to their flexibility.

[0004] Current perovskite / CIGS laminated solar cells are mainly two-terminal or four-terminal structures. Among them, the sub-cells of the two-terminal structure are connected in series, and the output current is limited by the sub-cell with smaller generated current. The highest photoelectric conversion efficiency of the existing two-terminal perovskite / CIGS laminated solar cell is only 26.3%. The sub-cells of the four-terminal structure are connected in parallel, although there is no current matching problem, but the stacking method causes the light to need to pass through multiple layers of ITO glass to reach the bottom cell, which is easy to cause parasitic absorption. The highest photoelectric conversion efficiency of the existing four-terminal perovskite / CIGS laminated solar cell is only 29.36%, and the photoelectric conversion efficiency is low. SUMMARY

[0005] The present application aims to provide a three-terminal back contact perovskite / CIGS laminated solar cell and application thereof. The three-terminal back contact perovskite / CIGS laminated solar cell provided by the present application has high photoelectric conversion efficiency.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The present application provides a three-terminal back contact perovskite / CIGS laminated solar cell, comprising a perovskite top cell and a CIGS bottom cell. The perovskite top cell comprises a first metal electrode 1, an anti-reflection layer 2, and an ITO transparent electrode 3, an electron transport layer 4, a perovskite light absorption layer 5, and a hole transport layer 6 arranged in sequence from top to bottom; The upper surface of the ITO transparent electrode 3 is divided into a blank area and an effective area; the first metal electrode 1 and the anti-reflection layer 2 cover the blank area and the effective area, respectively; The electron transport layer 4, the perovskite light absorption layer 5, the hole transport layer 6, and the CIGS bottom cell are arranged in sequence from top to bottom in the area corresponding to the effective area of the bottom surface of the ITO transparent electrode 3; The CIGS bottom cell comprises a CIGS light absorption layer 7, a buffer layer 8, a second metal electrode 9, a passivation layer 10, a back field layer 11, and a third metal electrode 12; The longitudinal section of the CIGS light absorption layer 7 and the buffer layer 8 is in the shape of “┏” or “┓”, and the outer straight angle of the buffer layer 8 is matched with the inner straight angle of the CIGS light absorption layer 7; The top surface of the second metal electrode 9 is in contact with the bottom surface of the horizontal part of the buffer layer 8, and the bottom surface of the second metal electrode 9 is flush with the bottom surface of the vertical part of the buffer layer 8; The passivation layer 10 is in contact with the vertical part of the buffer layer 8 and the bottom surface of the second metal electrode 9, and the side surface of the passivation layer 10 is matched with the inner side of the vertical part of the CIGS light absorption layer 7, and the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light absorption layer 7; The back field layer 11 is in contact with the vertical part of the CIGS light absorption layer 7 and the bottom surface of the passivation layer 10; The third metal electrode 12 is in contact with the bottom surface of the back field layer 11.

[0007] Preferably, the width of the vertical part of the CIGS light absorption layer 7 is 40-50% of the total width of the back field layer 11.

[0008] Preferably, the width of the vertical part of the buffer layer 8 is 10-20% of the total width of the passivation layer 10.

[0009] Preferably, the blank area and the effective area are divided left and right on the upper surface of the ITO transparent electrode 3, and the proportion of the blank area is 5-10%.

[0010] Preferably, the ratio of the amount of substance of Ga element to the total amount of substance of Ga element and In element in the CIGS light absorption layer 7 is (0.2-0.3):1.

[0011] Preferably, the thickness of the first metal electrode 1 is 80-150 nm; The thickness of the anti-reflection layer 2 is 50-120 nm; The thickness of the ITO transparent electrode 3 is 50-120 nm; The thickness of the electron transport layer 4 is 40-60 nm; The thickness of the perovskite light absorption layer 5 is 800-1000 nm; The thickness of the hole transport layer 6 is 40-60 nm.

[0012] Preferably, the total thickness of the perovskite top cell is 900-1200 nm.

[0013] Preferably, the thickness of the CIGS light absorption layer 7 is 3200-3400 nm; The thickness of the buffer layer 8 is 40-60 nm; The thickness of the second metal electrode 9 is 80-150 nm; The thickness of the passivation layer 10 is 30-60 nm; The thickness of the back field layer 11 is 40-60 nm; The thickness of the third metal electrode 12 is 80-150 nm.

[0014] Preferably, the total thickness of the CIGS bottom cell is 3500-3700 nm.

[0015] The application also provides the application of the three-terminal back contact perovskite / CIGS laminated solar cell in lightweight and flexible devices and building integrated photovoltaics.

[0016] The application provides a three-terminal back contact perovskite / CIGS laminated solar cell, which comprises a perovskite top cell and a CIGS bottom cell; the perovskite top cell comprises a first metal electrode 1, an anti-reflection layer 2 and an ITO transparent electrode 3, an electron transport layer 4, a perovskite light absorption layer 5 and a hole transport layer 6 arranged in sequence from top to bottom; the upper surface of the ITO transparent electrode 3 is divided into a blank area and an effective area; the first metal electrode 1 and the anti-reflection layer 2 cover the blank area and the effective area respectively; the electron transport layer 4, the perovskite light absorption layer 5, the hole transport layer 6 and the CIGS bottom cell are arranged in sequence from top to bottom in the region corresponding to the effective area on the bottom surface of the ITO transparent electrode 3; the CIGS bottom cell comprises a CIGS light absorption layer 7, a buffer layer 8, a second metal electrode 9, a passivation layer 10, a back field layer 11 and a third metal electrode 12; the longitudinal section of the CIGS light absorption layer 7 and the buffer layer 8 is in the shape of '┏' or '┓', and the outer right angle of the buffer layer 8 is matched with the inner right angle of the CIGS light absorption layer 7; the top surface of the second metal electrode 9 is in contact with the bottom surface of the horizontal part of the buffer layer 8, and the bottom surface of the second metal electrode 9 is flush with the bottom surface of the vertical part of the buffer layer 8; the passivation layer 10 is in contact with the vertical part of the buffer layer 8 and the bottom surface of the second metal electrode 9, the side surface of the passivation layer 10 is matched with the inner side of the vertical part of the CIGS light absorption layer 7, and the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light absorption layer 7; the back field layer 11 is in contact with the vertical part of the CIGS light absorption layer 7 and the bottom surface of the passivation layer 10; and the third metal electrode 12 is in contact with the bottom surface of the back field layer 11.The top cell of the laminated solar cell adopts a perovskite top cell, the bottom cell adopts a CIGS bottom cell, and the laminated solar cell is designed into a three-terminal structure, so that the laminated solar cell has excellent flexibility and good long-term stability; the upper surface of the ITO transparent electrode 3 is divided into a blank area and an effective area, the first metal electrode 1 is arranged on the blank area, the anti-reflection layer 2 is arranged on the effective area, and the electron transport layer 4, the perovskite light absorption layer 5, the hole transport layer 6 and the CIGS bottom cell are sequentially arranged from top to bottom in the area corresponding to the effective area on the bottom surface of the ITO transparent electrode 3, so that the first metal electrode can be maximally avoided to shield sunlight, and the utilization rate of sunlight can be improved; the hole transport layer is directly contacted with the CIGS light absorption layer 7, the CIGS light absorption layer 7 is arranged in a “┏” shape or a “┓” shape, the buffer layer 8, the second metal electrode 9 and the passivation layer 10 of the CIGS bottom cell are arranged on the back surface of the CIGS bottom cell, the side surface of the passivation layer 10 is attached to the inner side of the vertical part of the CIGS light absorption layer 7, the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light absorption layer 7, the buffer layer 8 and the second metal electrode 9 can be completely electrically isolated from the back field layer 11, the use of the transparent electrode can be reduced, and then the optical parasitic absorption can be reduced, and the photoelectric conversion efficiency of the cell can be improved. The results of the embodiment show that the three-terminal back contact perovskite / CIGS laminated solar cell provided by the application has a photoelectric conversion utilization rate of 33.20%, and has high photoelectric conversion efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structure schematic diagram of the three-terminal back contact perovskite / CIGS laminated solar cell of the application, wherein 1 is a first metal electrode, 2 is an anti-reflection layer, 3 is an ITO transparent electrode, 4 is an electron transport layer, 5 is a perovskite light absorption layer, 6 is a hole transport layer, 7 is a CIGS light absorption layer, 8 is a buffer layer, 9 is a second metal electrode, 10 is a passivation layer, 11 is a back field layer, and 12 is a third metal electrode; Figure 2 It is a structure schematic diagram of the two-terminal perovskite / CIGS laminated solar cell of the comparative example 1 of the application, wherein 13 is an anti-reflection layer, 14 is a transparent electrode, 15 is an electron transport layer, 16 is a perovskite absorption layer, 17 is a hole transport layer, 18 is a transparent electrode, 19 is a buffer layer, 20 is a CIGS light absorption layer, 21 is a back field layer, and 22 is a metal electrode; Figure 3A structure schematic diagram of a four-terminal perovskite / CIGS tandem solar cell of the present application comparative example 2, wherein 23 is an anti-reflection layer, 24 is a transparent electrode, 25 is an electron transport layer, 26 is a perovskite absorption layer, 27 is a hole transport layer, 28 is a transparent electrode, 29 is a transparent electrode, 30 is a buffer layer, 31 is a CIGS light absorption layer, 32 is a back field layer, and 33 is a metal electrode; Figure 4 A comparative diagram of EQE of the three-terminal back contact perovskite / CIGS tandem solar cell of the present application example 1, the two-terminal perovskite / CIGS tandem solar cell of comparative example 1, and the four-terminal perovskite / CIGS tandem solar cell of comparative example 2; Figure 5 A J-V curve diagram of the three-terminal back contact perovskite / CIGS tandem solar cell of the present application example 1. DETAILED DESCRIPTION

[0018] The present application provides a three-terminal back contact perovskite / CIGS tandem solar cell, comprising a perovskite top cell and a CIGS bottom cell.

[0019] In the present application, the perovskite top cell comprises a first metal electrode 1, an anti-reflection layer 2, and an ITO transparent electrode 3, an electron transport layer 4, a perovskite light absorption layer 5, and a hole transport layer 6 arranged in order from top to bottom.

[0020] In the present application, the upper surface of the ITO transparent electrode 3 is divided into a blank area and an effective area; as shown in the present application, in one embodiment, the blank area and the effective area are divided left and right on the upper surface of the ITO transparent electrode 3; the blank area can be arranged at the edge of the upper surface of the ITO transparent electrode 3; the proportion of the blank area can be 5-10%, and can also be 6-8%. Figure 1

[0021] As an embodiment of the present application, the thickness of the ITO transparent electrode 3 can be 50-120 nm, and can also be 100 nm.

[0022] In the present application, the first metal electrode 1 covers the blank area. As an embodiment of the present application, the first metal electrode 1 can be an Ag electrode; the thickness of the first metal electrode 1 can be 80-150 nm, and can also be 100 nm; In the present application, the anti-reflection layer 2 covers the effective area. The anti-reflection layer 2 can be a MgF2 anti-reflection layer; the thickness of the anti-reflection layer 2 can be 50-120 nm, and can also be 100 nm; ​In the present invention, the electron transport layer 4 is disposed in the area corresponding to the bottom surface of the ITO transparent electrode 3 and the active area. The electron transport layer 4 can be a ZnO electron transport layer; the thickness of the electron transport layer 4 can be 40 - 60 nm, or can also be 50 nm; In the present invention, the perovskite light absorption layer 5 is disposed in the area corresponding to the bottom surface of the electron transport layer 4 and the active area. The perovskite light absorption layer 5 can be a CsPbI3 light absorption layer; the thickness of the perovskite light absorption layer 5 can be 800 - 1000 nm, or can also be 900 nm; In the present invention, the hole transport layer 6 is disposed in the area corresponding to the bottom surface of the perovskite light absorption layer 5 and the active area. The hole transport layer 6 can be a MoO3 hole transport layer; the thickness of the hole transport layer 6 can be 40 - 60 nm, or can also be 50 nm.

[0023] Limiting the materials and thicknesses of each layer in the perovskite top cell within the above ranges in the present invention can better improve the photoelectric conversion efficiency of the top cell.

[0024] In the present invention, the first metal electrode is responsible for collecting the photo-generated electrons generated by the top cell; the antireflection layer 2 reduces the light reflection loss; the ITO transparent electrode 3 can transmit light and transport charges. By dividing the ITO transparent electrode 3 into a blank area and an active area, the first metal electrode can be disposed in the blank area and the antireflection layer 2 can be disposed in the active area, which can avoid the occlusion of sunlight by the first metal electrode to the greatest extent and improve the utilization rate of sunlight; the electron transport layer 4 is responsible for transporting electrons; the perovskite light absorption layer 5 is responsible for absorbing photons and generating electron-hole pairs; the hole transport layer 6 is responsible for transporting holes and also has the function of a tunneling junction to transport holes to the CIGS light absorption layer 7.

[0025] As an embodiment of the present invention, the total thickness of the perovskite top cell can be 900 - 1200 nm, or can also be 950 - 1150 nm, or can also be 1000 - 1100 nm. Limiting the total thickness of the perovskite top cell within the above ranges in the present invention can optimize the spectral distribution, enable high-energy photons to be effectively absorbed by the top cell, while low-energy photons pass through to the bottom cell, thereby making full use of the entire spectrum and improving the overall photoelectric conversion efficiency of the tandem solar cell.

[0026] As Figure 1 shown, in the present invention, the CIGS bottom cell is disposed in the area corresponding to the bottom surface of the hole transport layer 6 and the active area.

[0027] In the present invention, the CIGS bottom cell includes a CIGS light absorption layer 7, a buffer layer 8, a second metal electrode 9, a passivation layer 10, a back field layer 11, and a third metal electrode 12.

[0028] In the present application, the CIGS light-absorbing layer 7 and the buffer layer 8 are both in the shape of "┏" or "┓", and the outer right angle of the buffer layer 8 is in contact with the inner right angle of the CIGS light-absorbing layer 7; in an embodiment of the present application, as shown in Figure 1 the longitudinal section of the CIGS light-absorbing layer 7 and the buffer layer 8 are both in the shape of "┓".

[0029] In an embodiment of the present application, the ratio of the amount of substance of Ga element to the total amount of substance of Ga element and In element in the CIGS light-absorbing layer 7 is (0.2~0.3):1, and can also be (0.2~0.25):1; the thickness of the horizontal part of the CIGS light-absorbing layer 7 can be 3200~3400nm, or 3300nm.

[0030] In an embodiment of the present application, the buffer layer 8 can be a CdS buffer layer; the thickness of the horizontal part of the buffer layer 8 can be 40~60nm, or 50nm.

[0031] In the present application, the top surface of the second metal electrode 9 is in contact with the bottom surface of the horizontal part of the buffer layer 8, and the bottom surface of the second metal electrode 9 is flush with the bottom surface of the vertical part of the buffer layer 8.

[0032] In an embodiment of the present application, the second metal electrode 9 can be an Ag electrode; the thickness of the second metal electrode 9 can be 80~150nm, or 100nm.

[0033] In the present application, the passivation layer 10 is in contact with the vertical part of the buffer layer 8 and the bottom surface of the second metal electrode 9, and the side surface of the passivation layer 10 is in contact with the inner side of the vertical part of the CIGS light-absorbing layer 7, and the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light-absorbing layer 7.

[0034] In an embodiment of the present application, the passivation layer 10 can be an Al2O3 passivation layer; the thickness of the passivation layer 10 can be 30~60nm, or 50nm.

[0035] In an embodiment of the present application, the width of the vertical part of the buffer layer 8 can be 10~20% of the total width of the passivation layer 10, or 14~19%, or 16~18%. Limiting the width of the vertical part of the buffer layer 8 to the above range can reserve a position for the second metal electrode 9 to collect electrons.

[0036] In the present application, the back field layer 11 is in contact with the vertical part of the CIGS light-absorbing layer 7 and the bottom surface of the passivation layer 10.

[0037] As an embodiment of the present application, the back field layer 11 can be a MoSe2 back field layer; the thickness of the back field layer 11 can be 40-60 nm, or 50 nm.

[0038] As an embodiment of the present application, the vertical part width of the CIGS light absorption layer 7 can be 40-50% of the total width of the back field layer 11, or 40-48%, or 40-44%. Defining the vertical part width of the CIGS light absorption layer 7 in the above range can better transport holes to the back field layer 11.

[0039] In the present application, the third metal electrode 12 is in contact with the bottom surface of the back field layer 11.

[0040] As an embodiment of the present application, the third metal electrode 12 can be a Mo electrode; the thickness of the third metal electrode 12 can be 80-150 nm, or 100 nm.

[0041] Defining the material and size of each layer in the CIGS bottom cell in the above range can better improve the photoelectric conversion efficiency of the bottom cell.

[0042] In the present application, the CIGS light absorption layer is responsible for absorbing long-wave band photons that cannot be absorbed by the top cell and generating electron-hole pairs; the buffer layer 8 and the CIGS light absorption layer form a heterojunction to transport electrons to the negative second metal electrode 9; the second metal electrode 9 is responsible for collecting photo-generated electrons generated by the bottom cell; the passivation layer 10 separates the negative second metal electrode 9 of the CIGS bottom cell and the back field layer 11 that collects photo-generated holes from each other to avoid a large number of hole-electron recombination; by contacting the top surface of the second metal electrode 9 with the bottom surface of the horizontal part of the buffer layer 8, and the bottom surface of the second metal electrode 9 is flush with the bottom surface of the vertical part of the buffer layer 8, the passivation layer 10 is in contact with the vertical part of the buffer layer 8 and the bottom surface of the second metal electrode 9, and the side surface of the passivation layer 10 is in contact with the inside of the vertical part of the CIGS light absorption layer 7, the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light absorption layer 7, and the back field layer 11 is in contact with the vertical part of the CIGS light absorption layer 7 and the bottom surface of the passivation layer 10, it can make the photo-generated holes generated by the bottom cell and the top cell be successfully transported while avoiding a large number of hole-electron recombination, and realize efficient operation of the stacked cell; the back field layer 11 improves the interface contact between the CIGS light absorption layer and the third metal electrode 12, blocks electrons and transports holes; the third metal electrode 12 is responsible for collecting photo-generated holes generated by the bottom cell and the top cell, and is a common electrode.

[0043] As an embodiment of the present application, the total thickness of the CIGS bottom cell can be 3500-3700 nm, 3550-3650 nm, or 3600-3650 nm. The present application limits the total thickness of the CIGS bottom cell to the above range, so that the long-wave near-infrared light transmitted by the perovskite top cell can be more fully absorbed, the photocurrent contribution of the bottom cell is improved, and the photoelectric conversion efficiency is improved.

[0044] The bottom cell of the laminated solar cell of the present application adopts a CIGS bottom cell, and the laminated solar cell is designed as a three-terminal structure, so that the laminated solar cell has excellent flexibility and good long-term stability. By dividing the upper surface of the ITO transparent electrode 3 into a blank area and an effective area, setting the first metal electrode 1 on the blank area, setting the anti-reflection layer 2 on the effective area, and setting the electron transport layer 4, the perovskite light absorption layer 5, the hole transport layer 6, and the CIGS bottom cell in the area corresponding to the bottom surface of the ITO transparent electrode 3 and the effective area from top to bottom, the first metal electrode can be maximally avoided to block sunlight, and the utilization rate of sunlight can be improved. By directly contacting the hole transport layer with the CIGS light absorption layer 7, and setting the CIGS light absorption layer 7 as a "┏" shape or a "┓" shape structure, the buffer layer 8, the second metal electrode 9, and the passivation layer 10 of the CIGS bottom cell can be placed on the back surface of the CIGS bottom cell, at the same time, the side surface of the passivation layer 10 is attached to the inner side of the vertical part of the CIGS light absorption layer 7, and the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light absorption layer 7, so that the buffer layer 8 and the second metal electrode 9 can be completely electrically isolated from the back field layer 11, and the use of the transparent electrode can be reduced, thereby reducing optical parasitic absorption and improving the photoelectric conversion efficiency of the cell.

[0045] In the present application, the preparation method of the perovskite top cell and the CIGS bottom cell in the three-terminal back contact perovskite / CIGS laminated solar cell can adopt the method commonly used by those skilled in the art to prepare the top cell and the bottom cell. In the present application, the preparation method of the perovskite top cell and the CIGS bottom cell includes but is not limited to solution method or vacuum deposition.

[0046] The present application also provides the application of the three-terminal back contact perovskite / CIGS laminated solar cell described in the above technical solution in lightweight and flexible devices and building integrated photovoltaics.

[0047] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0048] Example 1 A three-terminal back-contact perovskite / CIGS tandem solar cell has a structure as Figure 1 shown, and is composed of a perovskite top cell (total thickness 1200 nm) and a CIGS bottom cell (total thickness 3650 nm); The perovskite top cell includes a first metal electrode 1 (Ag electrode, thickness 100 nm), an antireflection layer 2 (MgF2 antireflection layer, thickness 100 nm), and an ITO transparent electrode 3 (thickness 100 nm), an electron transport layer 4 (ZnO electron transport layer, thickness 50 nm), a perovskite light absorption layer 5 (CsPbI3 light absorption layer, thickness 900 nm), and a hole transport layer 6 (MoO3 hole transport layer, thickness 50 nm) arranged in sequence from top to bottom; The upper surface of the ITO transparent electrode 3 is divided into a blank area and an effective area; the blank area and the effective area are divided left and right on the upper surface of the ITO transparent electrode 3; the blank area is arranged at the left edge of the upper surface of the ITO transparent electrode 3; the proportion of the blank area is 9%; The first metal electrode 1 and the antireflection layer (2) respectively cover the blank area and the effective area; The electron transport layer 4, the perovskite light absorption layer 5, the hole transport layer 6, and the CIGS bottom cell are sequentially arranged from top to bottom in the area corresponding to the effective area on the bottom surface of the ITO transparent electrode (3); The CIGS bottom cell consists of a CIGS light absorption layer 7 (horizontal part thickness 3300 nm), a buffer layer 8 (CdS buffer layer, horizontal part thickness 50 nm), a second metal electrode 9 (Ag electrode, thickness 100 nm), a passivation layer 10 (Al2O3 passivation layer, thickness 50 nm), a back surface field layer 11 (MoSe2 back surface field layer, thickness 50 nm), and a third metal electrode 12 (Mo electrode, thickness 100 nm); the molar ratio of Ga element to the total molar amount of Ga element and In element in the CIGS light absorption layer 7 is 0.2:1; The longitudinal cross-sections of the CIGS light absorption layer 7 and the buffer layer 8 are both in a "┓" shape structure, and the outer right angle of the buffer layer 8 is in contact with the inner right angle of the CIGS light absorption layer 7; The top surface of the second metal electrode 9 is in contact with the bottom surface of the horizontal part of the buffer layer 8, and the bottom surface of the second metal electrode 9 is flush with the bottom surface of the vertical part of the buffer layer 8; The passivation layer 10 is in contact with the vertical part of the buffer layer 8 and the bottom surface of the second metal electrode 9, and the side surface of the passivation layer 10 is attached to the inner side of the vertical part of the CIGS light absorbing layer 7, and the bottom surface of the passivation layer 10 is flush with the bottom surface of the vertical part of the CIGS light absorbing layer 7; the width of the vertical part of the CIGS light absorbing layer 7 is 40% of the total width of the back field layer 11; the width of the vertical part of the buffer layer 8 is 16% of the total width of the passivation layer 10 The back field layer 11 is in contact with the vertical part of the CIGS light absorbing layer 7 and the bottom surface of the passivation layer 10. The third metal electrode 12 is in contact with the bottom surface of the back field layer 11.

[0049] Comparative Example 1 A two-terminal stacked perovskite / CIGS stacked solar cell has a structure as shown in Figure 2 from top to bottom in order: an anti-reflection layer 13 (MgF2 anti-reflection layer, thickness of 100 nm), a transparent electrode 14 (ITO transparent electrode, thickness of 100 nm), an electron transport layer 15 (ZnO electron transport layer, thickness of 50 nm), a perovskite absorbing layer 16 (CsPbI3 light absorbing layer, thickness of 900 nm), a hole transport layer 17 (MoO3 hole transport layer, thickness of 50 nm), a transparent electrode 18 (ITO transparent electrode, thickness of 100 nm), a buffer layer 19 (CdS buffer layer, thickness of 50 nm), a CIGS light absorbing layer 20 (thickness of 3500 nm), a back field layer 21 (MoSe2 back field layer, thickness of 50 nm), and a metal electrode 22 (Mo electrode, thickness of 100 nm).

[0050] Comparative Example 2 A four-terminal stacked perovskite / CIGS stacked solar cell has a structure as shown in Figure 3 from top to bottom in order: an anti-reflection layer 23 (MgF2 anti-reflection layer, thickness of 100 nm), a transparent electrode 24 (ITO transparent electrode, thickness of 100 nm), an electron transport layer 25 (ZnO electron transport layer, thickness of 50 nm), a perovskite absorbing layer 26 (CsPbI3 light absorbing layer, thickness of 900 nm), a hole transport layer 27 (MoO3 hole transport layer, thickness of 100 nm), a transparent electrode 28 (ITO transparent electrode, thickness of 100 nm), a transparent electrode 29 (ITO transparent electrode, thickness of 100 nm), a buffer layer 30 (CdS buffer layer, thickness of 50 nm), a CIGS light absorbing layer 31 (thickness of 3500 nm), a back field layer 32 (MoSe2 back field layer, thickness of 50 nm), and a metal electrode 33 (Mo electrode, thickness of 100 nm).

[0051] The simulation software was used to simulate and calculate the laminated solar cells of Example 1, Comparative Examples 1-2, the simulation environment was 300K, and AM1.5G standard solar spectrum was used, and the simulation parameters are shown in Table 1.

[0052] Table 1 Simulation parameters

[0053] The EQE comparison diagram of the three-terminal back contact perovskite / CIGS laminated solar cell of Example 1, the two-terminal perovskite / CIGS laminated solar cell of Comparative Example 1 and the four-terminal perovskite / CIGS laminated solar cell of Comparative Example 2 is shown in Figure 4 , and it can be seen from Figure 4 that in the short wave band, the top cell absorbs, and it can be seen that the EQE curves of different structures are close in the short wave band, indicating that the current of the top cell under different structures is similar. The long wave band shows obvious difference, and it can be seen that the three-terminal structure has the largest area, the two-terminal structure is second, and the four-terminal structure is the smallest. This is mainly because the three-terminal structure removes the middle ITO electrode, effectively reducing the loss caused by the reflection and parasitic absorption of the filtered light transmitted by the top cell by the ITO layer, and the two-terminal structure has one layer of ITO layer, and the four-terminal structure has two layers of ITO layer, so the light loss of the bottom cell of the four-terminal laminated solar cell is the largest, and the two-terminal laminated is second.

[0054] The simulation results of the three-terminal back contact perovskite / CIGS laminated solar cell of Example 1, the two-terminal perovskite / CIGS laminated solar cell of Comparative Example 1 and the four-terminal perovskite / CIGS laminated solar cell of Comparative Example 2 are shown in Table 2, and the J-V curve diagram of the three-terminal back contact perovskite / CIGS laminated solar cell of Example 1 is shown in Figure 5 .

[0055] Table 2 Simulation results of the three-terminal back contact perovskite / CIGS laminated solar cell of Example 1, the two-terminal perovskite / CIGS laminated solar cell of Comparative Example 1 and the four-terminal perovskite / CIGS laminated solar cell of Comparative Example 2

[0056] It can be seen from Table 2 and Figure 5 that the three-terminal structure effectively reduces the optical loss caused by the parasitic absorption of the transparent electrode, and the efficiency is obviously improved compared with the two-terminal and four-terminal laminated architecture, and the three-terminal laminated solar cell is parallel between the two sub-cells, without the need to follow the strict current matching, and the efficiency is the sum of the top cell and the bottom cell efficiency.

[0057] The three-terminal back contact perovskite / CIGS laminated solar cell provided by the application has a photoelectric conversion utilization rate of 33.20%, and has high photoelectric conversion efficiency.

[0058] The above merely preferred embodiments of the present application, it should be noted that for those of ordinary skill in the art, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements should also be considered within the scope of the present application.

Claims

1. A three-terminal back-contact perovskite / CIGS tandem solar cell, characterized in that, The top cell includes a perovskite top cell and a CIGS bottom cell; The perovskite top cell includes a first metal electrode (1), an anti-reflection layer (2), and an ITO transparent electrode (3), an electron transport layer (4), a perovskite light absorption layer (5), and a hole transport layer (6) arranged in sequence from top to bottom; The upper surface of the ITO transparent electrode (3) is divided into a blank area and an effective area; the first metal electrode (1) and the anti-reflection layer (2) cover the blank area and the effective area, respectively; The electron transport layer (4), the perovskite light absorption layer (5), the hole transport layer (6), and the CIGS bottom cell are arranged in sequence from top to bottom in the area corresponding to the effective area on the bottom surface of the ITO transparent electrode (3); The CIGS bottom cell includes a CIGS light absorption layer (7), a buffer layer (8), a second metal electrode (9), a passivation layer (10), a back field layer (11), and a third metal electrode (12); The longitudinal section of the CIGS light absorption layer (7) and the buffer layer (8) is "┏" or "┓", and the outer straight angle of the buffer layer (8) is matched with the inner straight angle of the CIGS light absorption layer (7); The top surface of the second metal electrode (9) is in contact with the bottom surface of the horizontal part of the buffer layer (8), and the bottom surface of the second metal electrode (9) is flush with the bottom surface of the vertical part of the buffer layer (8); The passivation layer (10) is in contact with the vertical part of the buffer layer (8) and the bottom surface of the second metal electrode (9), and the side surface of the passivation layer (10) is matched with the inner side of the vertical part of the CIGS light absorption layer (7), and the bottom surface of the passivation layer (10) is flush with the bottom surface of the vertical part of the CIGS light absorption layer (7); The back field layer (11) is in contact with the vertical part of the CIGS light absorption layer (7) and the bottom surface of the passivation layer (10); The third metal electrode (12) is in contact with the bottom surface of the back field layer (11).

2. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 1, wherein The width of the vertical part of the CIGS light absorption layer (7) is 40-50% of the total width of the back field layer (11).

3. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 2, wherein, The width of the vertical part of the buffer layer (8) is 10-20% of the total width of the passivation layer (10).

4. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 1, wherein, The blank area and the effective area are divided left and right on the upper surface of the ITO transparent electrode (3), and the proportion of the blank area is 5-10%.

5. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 1, wherein, The ratio of the amount of substance of Ga element to the total amount of substance of Ga element and In element in the CIGS light absorption layer (7) is (0.2-0.3):

1.

6. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 1, wherein, The thickness of the first metal electrode (1) is 80-150 nm; The thickness of the anti-reflection layer (2) is 50-120 nm; The thickness of the ITO transparent electrode (3) is 50-120 nm; The thickness of the electron transport layer (4) is 40-60 nm; The thickness of the perovskite light absorption layer (5) is 800-1000 nm; The thickness of the hole transport layer (6) is 40-60 nm.

7. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 6, wherein, The total thickness of the perovskite top cell is 900-1200 nm.

8. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 1, wherein, The thickness of the horizontal part of the CIGS light absorption layer (7) is 3200-3400 nm; The thickness of the buffer layer (8) is 40-60 nm; The thickness of the second metal electrode (9) is 80-150 nm; The thickness of the passivation layer (10) is 30-60 nm; The thickness of the back field layer (11) is 40-60 nm; The thickness of the third metal electrode (12) is 80-150 nm.

9. The three-terminal back-contact perovskite / CIGS tandem solar cell of claim 8, wherein, The total thickness of the CIGS bottom cell is 3500-3700 nm.

10. Use of the three-terminal back-contact perovskite / CIGS tandem solar cell according to any one of claims 1-9 in lightweight and flexible devices and building integrated photovoltaics.

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