Perovskite tandem cell structure and photovoltaic module

Abstract

The utility model discloses a kind of perovskite laminated battery structure and photovoltaic module, it includes N-type monocrystalline silicon substrate, second passivation layer, polysilicon doped layer, buffer layer, TCO layer, hole transport layer, perovskite light-absorbing layer and electron transport layer are arranged from inside to outside on the front of N-type monocrystalline silicon substrate;Wherein, polysilicon doped layer is locally and interval arranged on the top surface of second passivation layer, buffer layer covers the top surface of polysilicon doped layer and second passivation layer;TCO layer is arranged on the top surface of buffer layer, the top surface of TCO layer is sequentially provided with hole transport layer, perovskite light-absorbing layer and electron transport layer from inside to outside.This application is stacked on TOPCon battery perovskite battery, to realize laminated solar cell, by two different band gap absorber battery through different absorption wider range wavelength sunlight, reduce photonic thermalization loss, make full use of sunlight spectrum, to greatly improve the photoelectric conversion efficiency of solar cell.

Description

Technical Field

[0001] This utility model belongs to the field of solar cells, specifically relating to a perovskite tandem cell structure and a photovoltaic module. Background Technology

[0002] N-type TOPCon bifacial photovoltaic cells, as a new generation of advanced technology, have emerged in the market and are widely favored by the industry. TOPCon cells are currently the most promising monocrystalline cells with a high market share, but their compatibility is poor and their photoelectric conversion efficiency has reached a bottleneck. To further improve cell efficiency, perovskite / monocrystalline tandem solar cells are one of the most promising technological directions for further improving the photoelectric conversion efficiency of monocrystalline silicon cells. They can fully utilize the solar spectrum and broaden the spectral response of the cells. Among them, crystalline silicon cells mainly absorb visible light, while perovskite cells have better absorption characteristics for visible and near-infrared light. The tandem design of monocrystalline and perovskite cells can effectively utilize solar energy over a wider spectral range to improve photoelectric conversion efficiency.

[0003] TOPCon cells are currently approaching their efficiency limit of 28.7%, making it difficult to improve photoelectric conversion efficiency further. Conventional TOPCon cells on the market have doped layers covering both sides of the silicon wafer, and the anti-reflection layer is composed of a passivation layer. Therefore, they suffer from the following technical defects: 1. The thickness of the doped layer in a typical TOPCon battery is generally around 120~130 nm. However, heavily doped polycrystalline silicon has a free carrier absorption effect, which will cause severe parasitic absorption of photons in the long wavelength range, and will also lead to a decrease in the current density of the battery. 2. The passivation layer forms the antireflection layer, which only serves to reduce reflection and does not consider compatibility; that is, it is incompatible with perovskite solar cells and cannot be stacked. Specifically, due to the interface defects between the polycrystalline silicon doped layer and the TCO layer, the probability of charge recombination is reduced, making it impossible for perovskite-silicon stacked solar cells to better integrate different material layers to improve the overall efficiency of the cell. Summary of the Invention

[0004] The purpose of this invention is to provide a perovskite tandem cell structure that can significantly improve the photoelectric conversion efficiency of solar cells, based on existing technologies. This invention directly fabricates perovskite cells on existing TOPCon cells, achieving efficient combination and utilization of the solar spectrum and superposition of open-circuit voltages, thus significantly improving the theoretical conversion efficiency.

[0005] The technical solution of this utility model is: A perovskite tandem solar cell structure includes an N-type monocrystalline silicon substrate. On the front side of the N-type monocrystalline silicon substrate, from the inside out, are disposed a second passivation layer, a polycrystalline silicon doped layer, a buffer layer, a TCO layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer. The polycrystalline silicon doped layers are locally spaced on the top surface of the second passivation layer, and the buffer layer covers the top surfaces of the polycrystalline silicon doped layer and the second passivation layer. The TCO layer is disposed on the top surface of the buffer layer, and on the top surface of the TCO layer, from the inside out, are sequentially disposed a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer.

[0006] In one embodiment, a P-type emitter, a first passivation layer, and a passivation antireflection layer are sequentially disposed on the back side of an N-type single-crystal silicon substrate from the inside to the outside; the first passivation layer is at least one of a SiO2 layer or an Al2O3 layer; the passivation antireflection layer is SiN... X At least one of the following: a passivation antireflection layer or a SiO2 layer; and the thickness of the passivation antireflection layer is 10~100nm.

[0007] In a preferred embodiment, the thickness of the P-type emitter layer is 20~100 nm.

[0008] In the perovskite tandem battery structure of this invention, a first metal electrode can be provided on the passivation antireflection layer 4, and a second metal electrode can be provided on the electron transport layer.

[0009] In one embodiment, the buffer layer is composed of NiOx, Al2O3, SiO2, V2O5, and MoO. x The buffer layer has a thickness of 10–20 nm, and the TCO layer has a thickness of 65–85 nm.

[0010] In a preferred embodiment, the buffer layer on the top surface of the polysilicon doped layer has an outward protrusion structure; the thickness of the buffer layer on the top surface of the polysilicon doped layer is the same as that of the buffer layer on the top surface of the second passivation layer.

[0011] The material of the TCO layer in this invention can be at least one of ITO, FTO, or AZO.

[0012] In this invention, the TCO layer on the top surface of the raised structure of the buffer layer has an outwardly raised structure. The TCO layer on the top surface of the raised structure of the buffer layer has the same thickness as the TCO layer on the top surface of the non-raised structure of the buffer layer; a recessed structure is provided on the hole transport layer, which corresponds to the raised structure on the TCO layer.

[0013] In this invention, the connection surface between the buffer layer and the TCO layer is uneven, and the connection surface between the TCO layer and the hole transport layer is uneven; the connection surface between the perovskite light-absorbing layer and the electron transport layer is planar, and the connection surface between the electron transport layers is planar.

[0014] In a preferred embodiment, the second passivation layer is at least one of a SiO2 layer or an Al2O3 layer, and the thickness of the second passivation layer is 1~2 nm.

[0015] In a preferred embodiment, the thickness of the polycrystalline silicon doped layer is 15~30 nm.

[0016] In a preferred embodiment, the thickness of the hole transport layer is 30-50 nm.

[0017] In a preferred embodiment, the thickness of the perovskite light-absorbing layer is 100~500 nm.

[0018] In a preferred embodiment, the thickness of the electron transport layer is 20~60 nm.

[0019] In a preferred embodiment, the thickness of the N-type single-crystal silicon substrate is 130~150nm.

[0020] This invention also includes a photovoltaic module, which includes the perovskite tandem cell structure of this invention.

[0021] This invention features a polycrystalline silicon doped layer disposed at intervals on the top surface of the second passivation layer, which can serve as a field passivation layer, reducing recombination and minimizing unnecessary parasitic absorption to avoid reducing optical loss.

[0022] This invention prepares a TCO film layer on a polycrystalline silicon doped layer. The TCO film layer has good carrier mobility and transmittance. Its lateral conductivity can not only reduce the thickness of the polycrystalline silicon doped layer of TOPCON to a certain extent and reduce costs, but also be compatible with perovskite cells. When prepared as a tandem cell, it can greatly improve the photoelectric conversion efficiency of solar cells.

[0023] This application stacks perovskite solar cells on TOPCon solar cells to further improve the efficiency of TOPCon solar cells, thereby realizing tandem solar cells. By using two cells with different bandgap absorbers to absorb a wider range of wavelengths of sunlight through differential absorption, photon thermal loss is reduced, and the solar spectrum is fully utilized, thereby greatly improving the photoelectric conversion efficiency of solar cells. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of one possible structure of the perovskite tandem battery of this utility model; In the figure, 1-N-type single crystal silicon substrate, 2-P-type emitter, 3-first passivation layer, 4-passivation antireflection layer, 5-second passivation layer, 6-polycrystalline silicon doped layer, 7-buffer layer, 8-TCO layer, 9-hole transport layer, 10-perovskite light-absorbing layer, 11-electron transport layer, 12-second metal electrode, 13-first metal electrode.

[0025] Figure 2 This is a schematic diagram of the battery structure in Comparative Example 1; In the figure, 101-N-type single crystal silicon substrate, 102-P-type emitter, 103-Al2O3 passivation layer; 104-SiNX / SiO2 passivation layer antireflection layer; 105-tunneling oxide layer; 106-POLY polycrystalline silicon layer; 107-TCO layer; 108-hole transport layer; 109-perovskite light-absorbing layer; 1010-electron transport layer; 1011-metal electrode. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the following examples.

[0027] Technical Terminology Explanation: PECVD: Plasma-enhanced chemical vapor deposition; LPCVD: Low-pressure chemical vapor deposition; ALD: Atomic Layer Deposition; TCO layer: Transparent conductive oxide; ITO, FTO, AZO, and ATO are types of TCO. ITO is indium tin oxide, FTO is fluorine-doped tin oxide, AZO is aluminum-doped tin oxide, and ATO is antimony-doped tin oxide.

[0028] Example like Figure 1 As shown, the perovskite tandem solar cell structure of this invention includes an N-type monocrystalline silicon substrate 1. On the front side of the N-type monocrystalline silicon substrate 1, from the inside out, are disposed a second passivation layer 5, a polycrystalline silicon doped layer 6, a buffer layer 7, a TCO layer 8, a hole transport layer 9, a perovskite light-absorbing layer 10, and an electron transport layer 11. On the back side of the N-type monocrystalline silicon substrate 1, from the inside out, are disposed a P-type emitter 2, a first passivation layer 3, and a passivation antireflection layer 4. A first metal electrode 13 is disposed on the passivation antireflection layer 4, and a second metal electrode 12 is disposed on the electron transport layer 11.

[0029] The thickness of the N-type single-crystal silicon substrate 1 is 130~150nm.

[0030] On the front side of the N-type single-crystal silicon substrate 1, the second passivation layer 5 is connected to the front side of the substrate, and the connection surface between the two is planar. The second passivation layer 5 is at least one of SiO2 layer or Al2O3 layer. The thickness of the second passivation layer 5 is 1~2 nm.

[0031] A polycrystalline silicon doped layer 6 is disposed on the second passivation layer 5, but it does not completely cover the second passivation layer 5. Instead, it is locally spaced on the top surface of the second passivation layer 5. This locally spaced arrangement effectively divides the polycrystalline silicon doped layer 6 into multiple parts, each spaced apart on the top surface of the second passivation layer 5. In this scheme, by selectively preparing the polycrystalline silicon doped layer 6, a field passivation effect can be achieved, reducing recombination; and unnecessary parasitic absorption can be reduced to avoid reducing optical loss. The thickness of the polycrystalline silicon doped layer 6 is 15~30nm.

[0032] The buffer layer 7 covers the top surface of the polysilicon doped layer 6 and the second passivation layer 5. Further, in the portion of the second passivation layer 5 where the polysilicon doped layer 6 is located, the buffer layer 7 covers the polysilicon doped layer 6; in the portion of the second passivation layer 5 where the polysilicon doped layer 6 is not located, the buffer layer 7 covers the second passivation layer 5. Because the buffer layer 7 needs to maintain a consistent thickness across all portions and the polysilicon doped layers 6 need to be spaced apart, the buffer layer 7 located on the top surface of the polysilicon doped layer 6 has an outward protruding structure. The buffer layer 7 located on the top surface of the polysilicon doped layer 6 has the same thickness as the buffer layer 7 located on the top surface of the second passivation layer 5.

[0033] Buffer layer 7 is composed of NiOx, Al2O3, SiO2, V2O5, and MoO. x At least one of Ag, Au, Cu, SnO2, ZnO, and TiO2 layers; the thickness of buffer layer 7 is 10–20 nm.

[0034] This application adds a buffer layer 7 between the polycrystalline silicon doped layer 6 and the TCO layer 8 to improve the performance of the battery structure. Taking the buffer layer 7 as an example, which uses Al2O3 or SiO2, it has the following functions: 1) Reducing interface defects: The buffer layer can effectively reduce interface defects between the polycrystalline silicon doped layer and the TCO layer, reduce the probability of charge recombination, and improve charge transport efficiency. 2) Improving charge transport performance: By optimizing interface characteristics, the buffer layer can improve charge transport performance, reduce carrier recombination losses, and thus improve the overall efficiency of the battery. 3) Improving battery stability: Appropriate buffer layer design can enhance battery stability and extend service life. Taking a dense NiOx layer as an example, when a sputtered dense NiOx layer is used as the buffer layer between the polycrystalline silicon doped layer and the TCO layer, this material can avoid shunting paths and enhance chemical bonding. The sputtered dense NiOx layer can effectively avoid shunting paths between the polycrystalline silicon doped layer and the highly conductive TCO layer, reducing current flow in unnecessary places, thereby improving the efficiency and stability of the battery. It can also help improve the adhesion and stability of the material, ensuring the long-term reliability of the battery under different environments. By using a sputtered dense NiOx layer as a buffer layer, perovskite silicon tandem solar cells can better integrate different material layers, improve photoelectric conversion efficiency, and enhance the stability and reliability of the battery.

[0035] The TCO layer 8 is disposed on the top surface of the buffer layer 7. The TCO layer 8 also needs to maintain a consistent thickness across its various portions. Due to the localized spacing of the polysilicon doped layer 6 on the second passivation layer 5 and the raised structure of the buffer layer 7, the TCO layer 8 on the top surface of the raised structure of the buffer layer 7 will also have an outward raised structure. Furthermore, the TCO layer 8 on the top surface of the raised structure of the buffer layer 7 has the same thickness as the TCO layer 8 on the top surface of the non-raised structure of the buffer layer 7. Clearly, the connection surface between the buffer layer 7 and the TCO layer 8 is a concave-convex surface. The material of the TCO layer 8 is at least one of ITO, FTO, or AZO. The thickness of the TCO layer 8 is 65~85 nm.

[0036] The top surface of the TCO layer 8 is provided with a hole transport layer 9, a perovskite light-absorbing layer 10, and an electron transport layer 11, arranged sequentially from the inside to the outside. The hole transport layer (9) has a recessed structure, which corresponds to the raised structure on the TCO layer 8. The connection surface between the TCO layer 8 and the hole transport layer 9 is a concave-convex surface. The thickness of the hole transport layer 9 is 30~50 nm.

[0037] The interface between the electron transport layer 10 and the perovskite light-absorbing layer 9 is planar. The thickness of the perovskite light-absorbing layer 10 is 100~500nm.

[0038] The connection surface between electron transport layer 11 and electron transport layer 10 is planar. The thickness of electron transport layer 11 is 20~60nm.

[0039] The thickness of the P-type emitter layer 2 on the back side of the substrate is 20~100nm.

[0040] The first passivation layer 3 is at least one of SiO2 layer or Al2O3 layer.

[0041] Passivation antireflection layer 4 is SiN X At least one of the following: a passivation antireflection layer or a SiO2 layer; the thickness of the passivation antireflection layer 4 is 10~100 nm.

[0042] A specific perovskite tandem solar cell structure in this example can be prepared by the following method: Fabrication of the underlying battery: 1. After cleaning and texturing an N-type single-crystal silicon substrate 1, a P-type emitter 2 is fabricated using a high-temperature diffusion furnace; 2. A tunneling oxide layer (as the second passivation layer 5) and a POLY polycrystalline silicon layer were prepared by LPCVD; 3. Prepare polycrystalline silicon doped layers using a high-temperature diffusion furnace; 4. Use a laser device to scan and etch the doped layer in the POLY doped layer region to prepare a polycrystalline silicon doped layer 6; the laser device parameters are: laser wavelength 1064nm, laser output power 30-90%, scanning speed 12000-15000mm / s, and frequency 10kHz. 5. Clean to remove deflection; 6. A P+ Al2O3 passivation layer was prepared using an ALD device as the first passivation layer 3; 7. A SiNX / SiO2 passivation antireflection layer was prepared by PECVD and used as passivation antireflection layer 4; Fabrication of the top cell: 1. A buffer layer 7 is prepared on the second passivation layer 5 and the polysilicon doped layer 6. The buffer layer 7 may be an Al2O3 layer, a SiO2 layer or a dense NiOx layer. 2. A TCO layer 8 is prepared on the buffer layer 7 using a PVD magnetron sputtering apparatus; 3. A hole transport layer 9 was prepared on the TCO layer 8 using a solution spin-coating method; 4. A perovskite light-absorbing layer 10 is prepared on the hole transport layer 9 by vapor deposition; 5. Electron transport layer 11 was prepared by solution spin coating; 6. Prepare metal electrodes using vacuum evaporation.

[0043] The perovskite tandem solar cell prepared is referred to as Example 1.

[0044] The perovskite tandem solar cell can also be further fabricated into a photovoltaic module using existing methods.

[0045] Comparative Example 1 like Figure 2 As shown, the comparative battery structure includes an N-type monocrystalline silicon substrate 101. On the back side of the N-type monocrystalline silicon substrate 101, from the inside to the outside, are sequentially arranged the following: a tunneling SiO2 layer 105 with a thickness of 1-2 nm, a POLY polycrystalline silicon layer 106 with a thickness of 15-30 nm, a TCO layer 107 with a thickness of 65-85 nm, a hole transport layer 108, a perovskite light-absorbing layer 108, and an electron transport layer 1010.

[0046] The POLY polysilicon layer 106 is planarly connected to the tunneling oxide layer 105, and the POLY polysilicon layer 106 is planarly connected to the TCO layer 107.

[0047] On the front side of the N-type single-crystal silicon substrate, from the inside out, there are sequentially arranged a front-side P-type emitter 102, an Al2O3 passivation layer 103, and a SiNX / SiO2 passivation antireflection layer 104.

[0048] A metal electrode 1011 is provided on the electron transport layer 1010, and a front electrode is provided on the passivation antireflection layer.

[0049] The preparation method of this comparative battery structure is as follows: Fabrication of the underlying battery: 1. A P+ emitter is fabricated using a diffusion furnace after texturing an N-type single-crystal silicon substrate; 2. A tunneling oxide layer of 1-2 nm and a polycrystalline silicon layer of 120-130 nm thickness were prepared by LPCVD. 3. Prepare polycrystalline silicon doped layers using a high-temperature diffusion furnace; 4. Clean to remove deflection; 5. Prepare a P+ Al2O3 passivation layer using an ALD apparatus; 6. Prepare SiNX / SiO2 passivation and antireflection layer using PECVD; Top cell fabrication: 1. TCO layers with a thickness of 65-85 nm were prepared using a PVD magnetron sputtering apparatus. 2. A hole transport layer was prepared using a solution spin-coating method; 3. Prepare perovskite light-absorbing layers using vapor deposition; 4. Electron transport layer prepared by solution spin coating; 5. Prepare metal electrodes using vacuum evaporation.

[0050] The battery structures prepared in Examples 1 and Comparative Example 1 were subjected to the following electrical performance verification tests: the photoelectric conversion efficiency and related electrical performance parameters of the batteries under standard illumination power were tested using an IV tester under simulated solar light source. Specific test results are shown in Table 1 (Eta: photoelectric conversion efficiency; Uoc: open-circuit voltage; Jsc: short-circuit current; FF: fill factor).

[0051] Table 1

[0052] As can be seen from the data in Table 1, the perovskite tandem solar cells prepared using the structure of this application show a slight increase in short-circuit current, fill factor, and turn-on voltage, and a significant improvement in conversion efficiency.

[0053] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A perovskite tandem solar cell structure, comprising an N-type monocrystalline silicon substrate (1), characterized in that... A second passivation layer (5), a polysilicon doped layer (6), a buffer layer (7), a TCO layer (8), a hole transport layer (9), a perovskite light-absorbing layer (10), and an electron transport layer (11) are disposed from the inside to the outside on the front side of the N-type single-crystal silicon substrate (1); wherein, the polysilicon doped layer (6) is disposed locally at intervals on the top surface of the second passivation layer (5), and the buffer layer (7) covers the top surface of the polysilicon doped layer (6) and the second passivation layer (5); the TCO layer (8) is disposed on the top surface of the buffer layer (7), and the hole transport layer (9), the perovskite light-absorbing layer (10), and the electron transport layer (11) are disposed sequentially from the inside to the outside on the top surface of the TCO layer (8).

2. The perovskite tandem solar cell structure according to claim 1, characterized in that... The back side of the N-type single-crystal silicon substrate (1) is provided with a P-type emitter (2), a first passivation layer (3), and a passivation antireflection layer (4) sequentially from the inside to the outside; the first passivation layer (3) is at least one of SiO2 layer or Al2O3 layer; the passivation antireflection layer (4) is SiN X At least one of the layers or SiO2 layers; and the thickness of the passivation antireflection layer (4) is 10~100nm.

3. The perovskite tandem solar cell structure according to claim 2, characterized in that... The thickness of the P-type emitter (2) is 20~100nm.

4. The perovskite tandem solar cell structure according to claim 2, characterized in that... A first metal electrode (13) is provided on the passivation antireflection layer (4), and a second metal electrode (12) is provided on the electron transport layer (11).

5. The perovskite tandem solar cell structure according to claim 1, characterized in that... The thickness of the buffer layer (7) is 10-20 nm, and the thickness of the TCO layer (8) is 65-85 nm.

6. The perovskite tandem solar cell structure according to claim 5, characterized in that... The buffer layer (7) located on the top surface of the polysilicon doped layer (6) has an outward protrusion structure; the buffer layer (7) located on the top surface of the polysilicon doped layer (6) has the same thickness as the buffer layer (7) located on the top surface of the second passivation layer (5).

7. The perovskite tandem solar cell structure according to claim 6, characterized in that... The TCO layer (8) on the top surface of the protruding structure of the buffer layer (7) has an outward protruding structure; the TCO layer (8) on the top surface of the protruding structure of the buffer layer (7) has the same thickness as the TCO layer (8) on the top surface of the non-protruding structure of the buffer layer (7); a recessed structure is provided on the hole transport layer (9), which corresponds to the protruding structure on the TCO layer (8).

8. The perovskite tandem solar cell structure according to claim 1, characterized in that... The connection surface between the buffer layer (7) and the TCO layer (8) is concave and convex, and the connection surface between the TCO layer (8) and the hole transport layer (9) is concave and convex; the connection surface between the perovskite light-absorbing layer (10) and the electron transport layer (11) is planar.

9. The perovskite tandem solar cell structure according to claim 1, characterized in that... The second passivation layer (5) is at least one of SiO2 layer or Al2O3 layer, and the thickness of the second passivation layer (5) is 1~2 nm; the thickness of the polycrystalline silicon doped layer (6) is 15~30 nm; the thickness of the hole transport layer (9) is 30~50 nm; the thickness of the perovskite light-absorbing layer (10) is 100~500 nm; the thickness of the electron transport layer (11) is 20~60 nm; and the thickness of the N-type single crystal silicon substrate (1) is 130~150 nm.

10. A photovoltaic module, characterized in that... It includes the perovskite tandem solar cell structure as described in any one of claims 1 to 9.

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