Solar cell

Abstract

The utility model discloses a solar cell which comprises a substrate, a hole transport layer, a light absorption layer, an electron transport layer, a transparent electrode layer and a metal electrode which are sequentially arranged in a laminated mode, the transparent electrode layer comprises a first electrode part and a second electrode part, and the second electrode part is located between the first electrode part and the metal electrode. The side, away from the electron transport layer, of the first electrode part is provided with a first surface, the projection of the second electrode part on the first surface is located in part of the first surface, and the projection of the second electrode part on the first surface covers the projection of the metal electrode on the first surface. Good ohmic contact is achieved under the condition that the overall optical transmittance is not affected, and the problem that the filling factor and the photoelectric conversion rate of a device are low due to a thick transparent electrode film layer is solved.

Description

Technical Field

[0001] This application relates to the field of solar cells, and more specifically, to a solar cell. Background Technology

[0002] Perovskite solar cells (PSCs), as a promising new type of solar cell, have attracted much attention since their initial emergence. Among them, semi-transparent perovskite solar cells have garnered significant attention and research due to their combination of energy conversion and decorative appeal, as well as the high photoelectric conversion efficiency of perovskite / silicon tandem solar cells. Transparent conductive oxide (TCO) films, with their low resistivity and high transmittance in the visible light range, show broad application prospects in thin-film solar cells. Particularly in the field of perovskite solar cells, TCO films, as transparent electrodes, are a crucial component.

[0003] When TCO is used as a window layer, in order to reduce parasitic light absorption in the near-infrared band, existing technologies generally choose TCO materials with low carrier concentration and high carrier mobility, such as indium zinc oxide (IZO) and In₂O₃:H. However, these TCO materials have poor contact characteristics with the metal electrode, resulting in large contact resistance, which in turn causes a large series resistance, affecting the device's fill factor (FF) and photoelectric conversion efficiency. While TCO materials such as indium tin oxide (ITO) and indium tungsten oxide doped with indium oxide (In2O3:WO3, abbreviated as IWO) have high carrier concentrations and can form good contacts with metal electrodes, the free carrier absorption effect caused by the high carrier concentration significantly reduces the optical transmittance in the near-infrared band, ultimately affecting the short-circuit current of the device. Although these two materials can be stacked, such as in composite transparent electrodes with IZO / ITO or In2O3:H / ITO structures, which can achieve both high optical transmittance and low contact resistance, good contact characteristics require a thicker TCO film layer, which affects the optical transmittance of the composite transparent electrode, resulting in poor final performance. Utility Model Content

[0004] This application provides a solar cell to solve the problem that the thick transparent electrode film layer in related technologies leads to low fill factor and photoelectric conversion efficiency of the device.

[0005] To achieve the above objectives, a solar cell is provided according to one aspect of this application, comprising a substrate, a hole transport layer, a light absorption layer, an electron transport layer, a transparent electrode layer, and a metal electrode arranged in sequence, wherein the transparent electrode layer includes a first electrode portion and a second electrode portion, the second electrode portion being located between the first electrode portion and the metal electrode, the first electrode portion having a first surface on the side facing away from the electron transport layer, the projection of the second electrode portion on the first surface being located in a portion of the first surface, and the projection of the second electrode portion on the first surface covering the projection of the metal electrode on the first surface.

[0006] Optionally, the metal electrode includes multiple grid lines spaced apart, and the second electrode portion consists of multiple structures spaced apart on the first surface, with each grid line corresponding to a multiple second electrode portion, and the projection of each second electrode portion on the first surface covering the projection of the corresponding metal electrode grid line on the first surface.

[0007] Optionally, the surfaces of each second electrode portion that are opposite to the first surface are parallel.

[0008] Optionally, the electron transport layer has a second surface on the side near the first electrode portion, and the projection of the first electrode portion onto the second surface completely coincides with the second surface.

[0009] Optionally, the thickness of the first electrode portion is less than or equal to the thickness of the second electrode portion.

[0010] Optionally, the thickness of the first electrode portion ranges from 15 to 150 nm.

[0011] Optionally, the carrier concentration of the first electrode is lower than that of the second electrode.

[0012] Optionally, the transparent electrode layer is a TCO layer, and both the first electrode portion and the second electrode portion are transparent conductive oxides.

[0013] Optionally, the substrate is a crystalline silicon substrate cell, wherein the tunneling composite layer is located between the silicon substrate cell and the hole transport layer.

[0014] Optionally, a buffer layer is provided between the transparent electrode layer and the electron transport layer.

[0015] Applying the technical solution of this application, a solar cell is provided, comprising a substrate, a hole transport layer, a perovskite absorber layer, an electron transport layer, a transparent electrode layer, and a metal electrode arranged in sequence. The transparent electrode layer is divided into two layers, including a first electrode portion and a second electrode portion. The second electrode portion is located between the metal electrode and the first electrode portion. The side of the first electrode portion facing away from the electron transport layer has a first surface. The projection of the second electrode portion on the first surface is located in a portion of the first surface. The second electrode portion and the portion of the first electrode portion are superimposed, which effectively reduces the contact resistance between the transparent electrode layer and the metal electrode, achieving good contact characteristics. Furthermore, since the projection of the second electrode portion on the first surface of the first electrode portion is located in a portion of the first surface, it can be seen that the first electrode portion has a portion that is not blocked by the second electrode portion. This portion provides good optical transmittance, thereby improving the fill factor and photoelectric conversion efficiency of the device without affecting the overall optical transmittance, and solving the problem that a thicker transparent electrode film layer leads to a lower fill factor and photoelectric conversion efficiency of the device. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 This is a schematic diagram of a cross-sectional structure of a solar cell according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of another solar cell cross-sectional structure provided according to an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of a cross-sectional structure of a solar cell provided in accordance with the comparative examples of this application.

[0020] The above figures include the following reference numerals:

[0021] 10. Substrate; 20. Hole transport layer; 30. Perovskite active layer; 40. Electron transport layer; 50. Transparent electrode layer; 60. Metal electrode; 51. First electrode section; 52. Second electrode section; 11. Crystalline silicon substrate cell; 12. Tunneling composite layer; 70. Buffer layer. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] To enable those skilled in the art to better understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0024] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art described in this application.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, products, or devices.

[0026] As described in the background section, when TCO is used as a window layer, the industry generally chooses TCO materials with low carrier concentration and high carrier mobility to reduce parasitic light absorption in the near-infrared band. However, such TCO materials have poor contact characteristics with metal electrodes. Although high carrier concentration TCO materials can form good contact with metal electrodes, the optical transmittance in the near-infrared band will decrease significantly, ultimately affecting the short-circuit current of the device. In the prior art, these two materials are stacked, but good contact characteristics require a thick TCO film layer, which affects the optical transmittance of the composite transparent electrode, resulting in poor final performance. Therefore, to solve the problem of low fill factor and photoelectric conversion efficiency caused by thick transparent electrode films in related technologies, this application proposes a solar cell.

[0027] Figure 1 and Figure 2 This is a cross-sectional view of a solar cell according to an embodiment of this application. Figure 1 and Figure 2 As shown, the solar cell includes:

[0028] A substrate 10, a hole transport layer 20, a perovskite active layer 30, an electron transport layer 40, a buffer layer 70, a transparent electrode layer 50, and a metal electrode 60 are sequentially stacked. The substrate 10 includes a crystalline silicon substrate cell 11 and a tunneling composite layer 12, which is located between the crystalline silicon substrate cell 11 and the hole transport layer 20. The transparent electrode layer 50 includes a first electrode portion 51 and a second electrode portion 52, which is located between the first electrode portion 51 and the metal electrode 60. The first electrode portion 51 has a first surface on the side away from the electron transport layer 40. The projection of the second electrode portion 52 on the first surface is located in a portion of the first surface, and the projection of the second electrode portion 52 on the first surface covers the projection of the metal electrode 60 on the first surface.

[0029] Using this embodiment, such as Figure 1 and Figure 2 As shown, by dividing the transparent electrode layer 50 into upper and lower parts, a first electrode portion 51 near the electron transport layer 40 covers the electron transport layer 40, and a second electrode portion 52 near the metal electrode 60 is located between the metal electrode 60 and the first electrode portion 51. The side of the first electrode portion 51 that is away from the electron transport layer 40 has a first surface, and the projection of the second electrode portion 52 on the first surface is located in part of the first surface. The projection of the metal electrode 60 on the first surface is covered by the projection of the second electrode portion 52 on the first surface. Thus, the metal electrode 60 is partially or entirely located on the second electrode portion 52, and the second electrode portion 52 is located on part of the first electrode portion 51. In this way, the transparent electrode layer 50 obtained by superimposing the second electrode portion 52 corresponding to the metal electrode 60 and the first electrode portion 51 achieves thickening, ensuring good contact characteristics between the transparent electrode layer 50 and the metal electrode 60, and ensuring good optical transmittance for the part of the first electrode portion 51 not covered by the second electrode portion 52. This design ensures good contact characteristics between the transparent electrode layer 50 and the metal electrode 60 without affecting the short-circuit current of the device, thereby improving the photoelectric conversion efficiency and FF of the device and solving the problem of low fill factor and photoelectric conversion efficiency caused by a thicker transparent electrode film.

[0030] In some alternative implementations, such as Figure 1 and Figure 2As shown, the metal electrode 60 consists of multiple spaced grid lines, and each grid line corresponds one-to-one with a multiple second electrode portions 52. The projection of each second electrode portion 52 onto the first surface correspondingly covers the projection of the grid lines of the metal electrode 60 onto the first surface. The portions of the second electrode portions 52 corresponding to the metal electrode 60 are superimposed with a transparent electrode layer 50 formed by the first electrode portion 51. The thickness of this layer is increased compared to the thickness of a single transparent electrode layer to achieve good ohmic contact. Furthermore, the areas where the grid lines are spaced are not or only minimally obstructed by the second electrode portions 52, maintaining good overall optical transmittance.

[0031] Specifically, the projected area of ​​the second electrode portion 52 on the first surface is greater than or equal to the projected area of ​​the metal electrode 60 on the first surface. For example, the projected area of ​​the second electrode portion 52 on the first surface can be equal to the projected area of ​​the metal electrode 60 on the first surface, and the projected shapes can also be the same.

[0032] For example, the material of the metal electrode 60 is selected from one or more of Au, Ag, Cu and Al, but is not limited to the above types. Those skilled in the art can make reasonable selections according to actual needs.

[0033] In some alternative implementations, such as Figure 1 and Figure 2 As shown, the surface of each second electrode portion 52 that is away from the first surface is parallel to the first surface and is located between the first electrode portion 51 and the metal electrode 60. This parallel structure makes the film thickness of the second electrode portion 52 uniform, which can ensure uniform charge transfer, avoid the generation of local hot spots, and improve the stability and reliability of the battery.

[0034] In some alternative implementations, such as Figure 1 and Figure 2 As shown, the electron transport layer 40 has a second surface on the side near the first electrode portion 51, and the projection of the first electrode portion 51 onto the second surface completely coincides with the second surface. This structure ensures contact between the electron transport layer 40 and the transparent electrode layer 50, guarantees optical transmittance in the near-infrared band, and reduces losses during charge transport.

[0035] For example, the material of the electron transport layer 40 can be selected from SnO2, ZnO, TiO2, fullerene derivatives, and C. 60 The electron transport layer 40 may be any one or a combination of materials. The material of the electron transport layer 40 may also be other types, but this application does not specifically limit the types used.

[0036] In some alternative implementations, such as Figure 1 and Figure 2As shown, the thickness of the first electrode portion 51 is less than or equal to the thickness of the second electrode portion 52. This difference in thickness can balance the characteristics of high optical transmittance and low contact resistance. The thinner first electrode portion 51 can ensure optical transmittance in the near-infrared band, while the thicker second electrode portion 52 can also ensure good contact characteristics with the metal electrode 60.

[0037] In some alternative embodiments, the thickness of the first electrode portion 51 ranges from 15 to 150 nm. The first electrode portion 51 having this thickness range provides sufficient conductivity while maintaining good transparency.

[0038] In some alternative embodiments, the carrier concentration of the first electrode portion 51 is lower than that of the second electrode portion 52. This difference in carrier concentration can effectively balance the characteristics of high optical transmittance and low contact resistance. The low carrier concentration of the first electrode portion 51 can effectively reduce parasitic light absorption in the near-infrared band. Although the low carrier concentration material may affect the contact characteristics between the first electrode portion 51 and the metal electrode 60, this application reduces the contact resistance between the transparent electrode layer 50 and the metal electrode 60 by using a high carrier concentration material for the second electrode portion 52 that contacts the metal electrode 60, thereby improving the photoelectric conversion efficiency of the device without affecting the optical transmittance.

[0039] For example, the material of the first electrode portion 51 is selected from one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO), tungsten-doped indium oxide (IWO), cerium-doped indium oxide (ICO), and zinc-doped tin oxide (ZTO); the material of the second electrode portion 52 can be selected from one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO), tungsten-doped indium oxide (IWO), cerium-doped indium oxide (ICO), and zinc-doped tin oxide (ZTO). The first electrode portion 51 and the second electrode portion 52 may also have other types, which are not specifically limited in the embodiments of this application.

[0040] For example, the transparent electrode layer 50 is a transparent conductive oxide (TCO), meaning that both the first electrode portion 51 and the second electrode portion 52 are transparent conductive oxides. The transparent electrode layer 50 of this type not only ensures high transmittance in the visible light range of the battery but also has low resistivity, improving charge transfer efficiency and providing a decorative effect.

[0041] In some alternative implementations, such as Figure 2As shown, the substrate 10 includes a crystalline silicon substrate cell 11, wherein a tunneling composite layer 12 is located between the crystalline silicon substrate cell and the hole transport layer. In this embodiment, the solar cell is a tandem solar cell. Using a tandem solar cell with a crystalline silicon substrate cell 11 not only provides a higher open-circuit voltage but also improves the efficiency of the solar cell and reduces costs.

[0042] However, it should be noted that the substrate 10 of the tandem solar cell in this application embodiment is not limited to the above types, and those skilled in the art can make reasonable selections according to actual needs.

[0043] Specifically, the material of the tunneling composite layer 12 can be selected from any one or a combination of multiple materials selected from indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide (In2O3:H), aluminum zinc oxide (AZO), zirconium-doped indium oxide (IZrO), zinc tin oxide (ZTO), a-Si, and nc-Si. The tunneling composite layer 12 can also have other types, which are not specifically limited in this application example.

[0044] In some alternative implementations, such as Figure 2 As shown, a buffer layer 70 is provided between the transparent electrode layer 50 and the electron transport layer 40. By providing the buffer layer 70, the interface contact can be effectively improved, interface defects can be reduced, and the stability and lifespan of the cell can be improved, making it suitable for solar cells that require long-term stable operation.

[0045] The material of the aforementioned buffer layer 70 may include, but is not limited to, SnO2, TiO2, and C. 60 A combination of one or more materials from PCBB-2CN-2C8 can be selected by those skilled in the art based on actual needs.

[0046] The material of the hole transport layer 20 may be one or more of the following materials, including but not limited to NiO, MoO3, Cu2O, CuI, CuPc, CuSCN, graphene oxide-reduction, PTAA, Spiro OMeTAD, Poly TPD, and polyvinylcarbazole (PVK). Those skilled in the art may make appropriate selections according to actual needs.

[0047] The solar cells provided in this application will be further described below with reference to embodiments and comparative examples.

[0048] Example 1

[0049] This embodiment provides a solar cell, the structure of which is as follows: Figure 2 As shown, the process flow is as follows:

[0050] S1. A crystalline silicon substrate cell 11 and a tunneling composite layer 12 are provided. A boron diffusion layer is fabricated on an N-type silicon wafer using a laser grooving and local diffusion process, and the borosilicate glass is removed and the silicon wafer is cleaned to form a monocrystalline silicon layer. A first intrinsic hydrogenated amorphous silicon layer and a second intrinsic hydrogenated amorphous silicon layer are formed on two opposite surfaces of the monocrystalline silicon layer using a plasma vapor deposition process. A P-type first hydrogenated amorphous silicon layer is formed on the surface of the first intrinsic hydrogenated amorphous silicon layer, and an N-type second hydrogenated amorphous silicon layer is formed on the surface of the second intrinsic hydrogenated amorphous silicon layer. A bottom TCO film layer is formed on the surface of the first hydrogenated amorphous silicon layer away from the monocrystalline silicon layer using a magnetron sputtering process. A first electrode is formed on the surface of the bottom TCO film layer away from the monocrystalline silicon layer using screen printing and high-temperature sintering. The material of the first electrode is Ag. An indium tin oxide (ITO) film layer is formed on the surface of the second hydrogenated amorphous silicon layer to form a tunneling layer, thus preparing a crystalline silicon substrate cell 11 and a tunneling composite layer 12.

[0051] S2. A hole transport layer 20 is provided, which is formed on an ITO substrate 10 using a deposition process to form a 2PACz layer with a thickness of 50nm as the hole transport layer 20.

[0052] S3. Provide a perovskite active layer 30, which is formed on the hole transport layer 20 by a deposition process and has a thickness of 300 nm.

[0053] S4. Provide an electron transport layer 40, and form C on the perovskite active layer 30 using a deposition process. 60 A layer, 30 nm thick, is used to form an electron transport layer 40;

[0054] S5. A buffer layer 70 is provided, and a tin oxide layer with a thickness of 50 nm is formed on the electron transport layer 40 using a deposition process to form the buffer layer 70.

[0055] S6. A first electrode portion 51 (TCO-1) is provided in the transparent electrode layer 50, which is a monolayer IZO electrode. The reaction chamber of the magnetron sputtering apparatus is evacuated before sputtering to a vacuum level below 1 × 10⁻⁶. -4 After Pa, argon gas is introduced into the reaction chamber at a flow rate of 80 sccm to maintain a pressure of 0.25 Pa and a temperature of room temperature. O2 is then introduced at a flow rate of 0.8 sccm. Once the chamber pressure stabilizes, a DC power supply is connected, and a DC power of 35 W is applied to the IZO target to deposit a 40 nm thick IZO thin film on the SnO2 buffer layer surface of the battery substrate as a transparent electrode, which is the first electrode portion 51 mentioned above.

[0056] S7. A second electrode portion 52 (TCO-2) is provided in the transparent electrode layer 50, which is an ITO electrode with a single-layer grid structure. The battery substrate is placed in a mask and sent into the chamber; the mask pattern shape is consistent with the metal grid electrode. The reaction chamber of the magnetron sputtering instrument is evacuated before sputtering, with a vacuum level below 1×10⁻⁶. -4 After Pa, argon gas is introduced into the reaction chamber at a flow rate of 60 sccm to maintain a pressure of 0.21 Pa and a temperature of room temperature. O2 is then introduced at a flow rate of 0.5 sccm. Once the chamber pressure stabilizes, a DC power supply is connected, and a DC power of 50 W is applied to the ITO target to deposit a 60 nm thick ITO film on the surface of the IZO layer of the battery substrate as the second transparent electrode, which is the aforementioned second electrode portion 52.

[0057] S8. Provide a metal electrode 60, which is formed on the conductive layer by a deposition process. The metal electrode 60 has a thickness of 40 nm and the material is Ag.

[0058] The solar cell prepared by the above steps has a structure comprising, in order from bottom to top: a crystalline silicon substrate cell 11, a tunneling composite layer 12, a hole transport layer 20, a perovskite active layer 30, an electron transport layer 40, a buffer layer 70, a first electrode portion 51, a second electrode portion 52, and a metal electrode 60, wherein the first electrode portion 51 and the second electrode portion 52 constitute a transparent electrode layer 50.

[0059] Example 2

[0060] The difference from Example 1 is that the thickness of the first electrode portion 51 is 15 nm.

[0061] Example 3

[0062] The difference from Embodiment 1 is that the thickness of the first electrode portion 51 is 150 nm and the thickness of the second electrode portion 52 is 150 nm.

[0063] Comparative Example 1

[0064] This comparative example provides a monolayer IZO electrode, the structure of which is as follows: Figure 3 As shown, the process flow is as follows:

[0065] S1 provides a crystalline silicon substrate cell 11 and a tunneling composite layer 12; a boron diffusion layer is fabricated on an N-type silicon wafer using a laser grooving local diffusion process, and the borosilicate glass is removed and the silicon wafer is cleaned to form a monocrystalline silicon layer; a first intrinsic hydrogenated amorphous silicon layer and a second intrinsic hydrogenated amorphous silicon layer are formed on two opposite surfaces of the monocrystalline silicon layer using a plasma vapor deposition process; a P-type first hydrogenated amorphous silicon layer is formed on the surface of the first intrinsic hydrogenated amorphous silicon layer, and an N-type second hydrogenated amorphous silicon layer is formed on the surface of the second intrinsic hydrogenated amorphous silicon layer using a plasma vapor deposition process; a bottom TCO film layer is formed on the surface of the first hydrogenated amorphous silicon layer away from the monocrystalline silicon layer using a magnetron sputtering process; a first electrode is formed on the surface of the bottom TCO film layer away from the monocrystalline silicon layer using screen printing and high-temperature sintering, the material of the first electrode being Ag; and an indium tin oxide (ITO) film layer is formed on the surface of the second hydrogenated amorphous silicon layer to form a tunneling layer, thus preparing a substrate 10 having a crystalline silicon substrate cell 11 and a tunneling composite layer 12;

[0066] S2 provides a hole transport layer 20, which is formed on an ITO substrate 10 using a deposition process to form a 2PACz layer with a thickness of 50nm, as the hole transport layer 20.

[0067] S3 provides a perovskite active layer 30, which is formed on the hole transport layer 20 by a deposition process and has a thickness of 300 nm.

[0068] S4 provides an electron transport layer 40, and C is formed on the perovskite active layer 30 using a deposition process. 60 A layer, 30 nm thick, is used to form an electron transport layer 40;

[0069] S5 provides a buffer layer 70, which is formed on the electron transport layer 40 by a deposition process with a tin oxide layer of 50 nm thickness to form the buffer layer 70.

[0070] S6 provides a transparent electrode layer 50, a monolayer IZO electrode. The reaction chamber of the magnetron sputtering apparatus is evacuated prior to sputtering to a vacuum level below 1 × 10⁻⁶. -4 After Pa, argon gas is introduced into the reaction chamber at a flow rate of 80 sccm to maintain a pressure of 0.25 Pa and a temperature of room temperature. O2 is then introduced at a flow rate of 0.8 sccm. Once the chamber pressure stabilizes, a DC power supply is connected, and a DC power of 35 W is applied to the IZO target to deposit a 40 nm thick IZO thin film on the SnO2 buffer layer surface of the battery substrate as a transparent electrode, i.e., transparent electrode layer 50.

[0071] S7 provides a metal electrode 60, which is formed on a conductive layer using a deposition process. The metal electrode 60 has a thickness of 40 nm and is made of Ag.

[0072] The solar cell prepared by the above steps has a structure comprising the following sequentially stacked elements: a crystalline silicon substrate cell 11, a tunneling composite layer 12, a hole transport layer 20, a perovskite active layer 30, an electron transport layer 40, a buffer layer 70, a transparent electrode layer 50, and a metal electrode 60.

[0073] The photoelectric performance of the tandem solar cells obtained in the above embodiments and Comparative Example 1 was tested. The photoelectric performance test parameters are shown in Table 1.

[0074] Table 1

[0075]

[0076] As shown in Table 1, compared to Comparative Example 1, the solar cell based on the bilayer TCO thin film in this embodiment exhibits significantly improved fill factor (FF) and power conversion efficiency (PCE) while maintaining the open circuit voltage (Voc) and short-circuit current density. This indicates that the composite TCO electrode in this application effectively improves photoelectric conversion efficiency and FF without affecting optical transmittance, and is suitable for perovskite-silicon tandem solar cells.

[0077] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0078] 1. This solar cell design introduces a first electrode portion and a second electrode portion in a transparent electrode layer. The second electrode portion is located between the metal electrode and the first electrode portion. The side of the first electrode portion away from the electron transport layer has a first surface. The projection of the second electrode portion on the first surface is located in a portion of the first surface. The second electrode portion and the portion of the first electrode portion are superimposed, which effectively reduces the contact resistance between the transparent electrode layer and the metal electrode, achieving good ohmic contact characteristics. The portion of the first electrode portion that is not blocked by the second electrode portion provides good optical transmittance. Thus, without affecting the overall optical transmittance, the FF and photoelectric conversion efficiency of the device are improved, solving the problem that the FF and photoelectric conversion efficiency of the device are low due to a thicker transparent electrode film layer.

[0079] 2. In this solar cell design, the first electrode portion, which is close to the electron transport layer, is thinner, while the second electrode portion, which is close to the metal electrode, is thicker. The thinner first electrode portion provides better light transmittance in the visible light range, while the thicker second electrode portion further reduces the contact resistance between the first electrode and the metal electrode, thereby improving the FF and photoelectric conversion efficiency of the device.

[0080] 3. In this solar cell design, the first electrode section, which is close to the electron transport layer, is made of a material with low carrier concentration. The light absorption rate of the transparent electrode with low carrier concentration in the near-infrared region is much lower than that of the transparent electrode with high carrier concentration. Thus, the first electrode section significantly improves the light transmittance in the visible light range. The second electrode section, which is close to the metal electrode, is made of a material with high carrier concentration. The contact resistance between the transparent electrode with high carrier concentration and the metal electrode is significantly reduced. Thus, the second electrode section further reduces the contact resistance between the second electrode and the metal electrode, achieving good ohmic contact and improving the FF and photoelectric conversion efficiency of the device.

[0081] 4. This solar cell improves interface contact and reduces interface defects by setting a buffer layer between the transparent electrode layer and the electron transport layer, thereby enhancing the stability and lifespan of the cell.

[0082] In summary, these optimization measures enable this solar cell to exhibit higher FF, photoelectric conversion efficiency, and longer lifespan in practical applications.

[0083] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A solar cell, characterized in that, include: A substrate, a hole transport layer, a light absorption layer, an electron transport layer, a transparent electrode layer, and a metal electrode are sequentially stacked. The transparent electrode layer includes a first electrode portion and a second electrode portion. The second electrode portion is located between the first electrode portion and the metal electrode. The first electrode portion has a first surface on the side opposite to the electron transport layer. The projection of the second electrode portion on the first surface is located in a portion of the first surface, and the projection of the second electrode portion on the first surface covers the projection of the metal electrode on the first surface.

2. The solar cell according to claim 1, characterized in that, The metal electrode includes a plurality of grid lines spaced apart, and the second electrode portion consists of a plurality of structures spaced apart on the first surface. The plurality of grid lines correspond one-to-one with the plurality of second electrode portions, and the projection of each second electrode portion on the first surface covers the projection of the corresponding metal electrode on the first surface.

3. The solar cell according to claim 2, characterized in that, The surfaces of each second electrode portion that are away from the first surface are parallel to each other.

4. The solar cell according to claim 1, characterized in that, The electron transport layer has a second surface on the side near the first electrode portion, and the projection of the first electrode portion onto the second surface completely coincides with the second surface.

5. The solar cell according to claim 1, characterized in that, The thickness of the first electrode portion is less than or equal to the thickness of the second electrode portion.

6. The solar cell according to claim 1, characterized in that, The thickness of the first electrode portion ranges from 15 to 150 nm.

7. The solar cell according to claim 1, characterized in that, The carrier concentration of the first electrode is lower than that of the second electrode.

8. The solar cell according to claim 1, characterized in that, The transparent electrode layer is a transparent conductive oxide layer.

9. The solar cell according to claim 1, characterized in that, The substrate includes a crystalline silicon substrate cell and a tunneling composite layer, wherein the tunneling composite layer is located between the silicon substrate cell and the hole transport layer.

10. The solar cell according to claim 1, characterized in that, It also includes a buffer layer disposed between the transparent electrode layer and the electron transport layer.

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