Solar cell and preparation method thereof
By incorporating a nanocrystalline silicon oxide layer and a gradient-doped microcrystalline silicon oxide layer in a heterojunction solar cell, the problems of low carrier migration efficiency and high contact resistance are solved, thereby improving current density and photoelectric conversion efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TRINA SOLAR CO LTD
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-08
AI Technical Summary
In existing heterojunction solar cells, an unsuitable thickness of the pa-Si:H thin film leads to low parasitic absorption and carrier migration efficiency, while a high Schottky barrier between na-Si:H and the transparent conductive layer increases contact resistance, affecting cell efficiency.
Nanocrystalline silicon oxide layer and gradient-doped microcrystalline silicon carbide layer are respectively set on the light-incident surface and the back-light surface of silicon substrate. By adjusting the carbon-oxygen ratio and crystallinity, a gradient built-in electric field is formed to optimize carrier migration and reduce the Schottky barrier.
It improves the current density and photoelectric conversion efficiency of solar cells, reduces contact resistance, and enhances the fill factor.
Smart Images
Figure CN122002964A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell technology, and in particular to a solar cell and a method for its fabrication. Background Technology
[0002] In the photovoltaic field, heterojunction solar cells (HJTs) have advantages such as simple structure, low processing temperature, good passivation effect, high open-circuit voltage, good temperature characteristics, and bifacial power generation, making them one of the hot topics in high-efficiency silicon-based solar cells.
[0003] Conventional methods for fabricating heterojunction solar cells involve depositing doped amorphous silicon (p / na-Si:H) onto the surface of intrinsic amorphous silicon (ia-Si:H), which effectively improves the open-circuit voltage. However, inappropriate pa-Si:H film thickness can lead to parasitic absorption, resulting in a decrease in short-circuit current. Furthermore, the amorphous structure hinders the migration of charge carriers (such as electrons and holes), increasing scattering and recombination losses during transport and preventing carriers from reaching the electrodes more efficiently, thus reducing the cell's current density and efficiency. In addition, a Schottky barrier exists between na-Si:H and the transparent conductive layer. The barrier height is significantly affected by the effective doping concentration and bandgap of the doped amorphous silicon layer, easily leading to excessively high interfacial contact resistance, resulting in increased series resistance and a decreased fill factor.
[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention
[0005] This application provides a solar cell and a method for fabricating the same, to solve or alleviate the technical problems mentioned above. The solar cell in this application facilitates carrier migration and can improve the current density and photoelectric conversion efficiency of the solar cell.
[0006] In a first aspect, embodiments of this application provide a solar cell, comprising: A silicon substrate having a light-incident surface and a back-light surface disposed opposite to each other; A first intrinsic amorphous silicon layer and a first doped layer are sequentially stacked on the light-incident surface and along the direction away from the silicon substrate; wherein, the first doped layer includes a nanocrystalline silicon oxide layer; A second intrinsic amorphous silicon layer, a second doped layer, and a second transparent conductive oxide layer are sequentially stacked on the backlight surface and along the direction away from the silicon substrate; wherein, the second doped layer includes a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, and a third microcrystalline silicon carbide layer sequentially stacked along the direction away from the silicon substrate, and the carbon-oxygen ratio of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer decreases sequentially; The first doped layer and the second doped layer have different doping types.
[0007] Optionally, the carbon-to-oxygen ratio of the first microcrystalline silicon dioxide layer is 0.6-0.8, the carbon-to-oxygen ratio of the second microcrystalline silicon dioxide layer is 0.4-0.6, and the carbon-to-oxygen ratio of the third microcrystalline silicon dioxide layer is 0.2-0.4.
[0008] Optionally, the crystallinity of the first microcrystalline silicon carbide layer is 30%-40%, the crystallinity of the second microcrystalline silicon carbide layer is 15%-25%, and the crystallinity of the third microcrystalline silicon carbide layer is 35%-45%.
[0009] Optionally, the first doped layer is a P-type doped layer, and the second doped layer is an N-type doped layer; The ratio of carbon, oxygen, and phosphorus in the first microcrystalline silicon carbide layer is (0.6-0.7):1:(0.01-0.025), the ratio of carbon, oxygen, and phosphorus in the second microcrystalline silicon carbide layer is (0.45-0.55):1:(0.025-0.045), and the ratio of carbon, oxygen, and phosphorus in the third microcrystalline silicon carbide layer is (0.2-0.3):1:(0.045-0.06).
[0010] Optionally, the thicknesses of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer are each and independently 1-15 nm.
[0011] Optionally, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.5-2; and / or The crystallinity of the nanocrystalline silicon oxide layer is greater than or equal to 25%.
[0012] Optionally, the first doped layer is a P-type doped layer, and the second doped layer is an N-type doped layer; The boron doping concentration in the nanocrystalline silicon oxide layer is 1×10⁻⁶. 19 -1×10 21 atom / cm 3 .
[0013] Optionally, the solar cell further includes: A first transparent conductive oxide layer and a first electrode are sequentially stacked on the first doped layer in a direction away from the silicon substrate; The second electrode is located on the side of the second transparent conductive oxide layer away from the silicon substrate.
[0014] Optionally, the first transparent conductive oxide layer includes MoO. x TeO x One or two of them.
[0015] Optionally, the solar cell further includes: Located between the first transparent conductive oxide layer and the first electrode, and stacked sequentially along the direction away from the silicon substrate are a metal layer, a long-wavelength reflective layer, an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer. The thickness of the metal layer is 5-10 nm, and the second electrode is a metal electrode with a thickness of 50-200 nm.
[0016] Optionally, the long-wavelength reflective layer includes one or both of ZnO and SrTiO3.
[0017] Secondly, embodiments of this application provide a method for preparing a solar cell, comprising: A silicon substrate is provided, the silicon substrate having a light-incident surface and a back-light surface disposed opposite to each other; A first intrinsic amorphous silicon layer and a first doped layer are sequentially formed on the light-incident surface; wherein, the first doped layer includes a nanocrystalline silicon oxide layer; A second intrinsic amorphous silicon layer, a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, a third microcrystalline silicon carbide layer, and a second transparent conductive oxide layer are sequentially formed on the backlight surface; wherein, the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer together constitute a second doped layer, and the carbon-oxygen ratio of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer decreases sequentially; The first doped layer and the second doped layer have different doping types.
[0018] Optionally, the method for preparing the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer includes: A plasma-enhanced chemical vapor deposition (PECVD) device is used to form a first microcrystalline silicon oxide layer on a second intrinsic amorphous silicon layer using hydrogen, silane, phosphine, and carbon dioxide gases; wherein the gas flow ratio of hydrogen to silane is 181-300, the gas flow ratio of phosphine to silane is 0.05-0.074, and the gas flow ratio of carbon dioxide to silane is 3.9-5. The PECVD equipment is continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide are adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane is 121-180, the gas flow rate ratio of phosphine to silane is 0.075-0.11, and the gas flow rate ratio of carbon dioxide to silane is 1.7-3.8; The PECVD equipment is continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide are adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane is 25-120, the gas flow rate ratio of phosphine to silane is 0.12-0.15, and the gas flow rate ratio of carbon dioxide to silane is 0.5-1.6.
[0019] The embodiments of this application employing the above-described technical solution may have the following advantages: The doped layer (i.e., the first doped layer) disposed on the light-incident surface of the silicon substrate includes a nanocrystalline silicon oxide layer (nc-SiO). x H-layer), wide-bandgap nc-SiO x H can reduce parasitic absorption, allowing more photons to be effectively absorbed and utilized, thereby improving the photoelectric conversion efficiency of solar cells; at the same time, well-crystallized nc-SiO x The presence of H facilitates the migration of charge carriers (such as electrons and holes), thereby reducing scattering and recombination losses during carrier transport. This allows charge carriers to reach the electrodes more efficiently, improving the current density and efficiency of the battery. Simultaneously, the doped layer (i.e., the second doped layer) on the back surface of the silicon substrate comprises a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, and a third microcrystalline silicon carbide layer. The optical and electrical properties of the microcrystalline silicon carbide layer are primarily influenced by the incorporation ratios of oxygen atoms, carbon atoms, and dopant atoms (e.g., phosphorus atoms). The carbon-oxygen ratio decreases sequentially from the first to the third microcrystalline silicon carbide layer, altering the electronic structure of these three silicon carbide (SiCO) layers, particularly the conduction band position. This sequentially lower conduction band position creates a gradient internal electric field, constructing a gradient-doped band structure that facilitates carrier migration and promotes improved battery efficiency. Meanwhile, adjusting the band structure can match the energy levels of the third microcrystalline silicon dioxide layer and the second transparent conductive oxide layer (TCO layer), thereby reducing the Schottky barrier between the second doped layer and the second TCO layer, effectively reducing the contact resistance and improving the fill factor of the battery. Attached Figure Description
[0020] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.
[0021] Figure 1 This is a schematic diagram of the structure of the solar cell of Embodiment 1 of this application; Figure 2 This is a schematic diagram of the structure of the solar cell in Embodiment 4 of this application.
[0022] Explanation of reference numerals in the attached figures: 100. Silicon substrate; 210, First intrinsic amorphous silicon layer; 220, First doped layer; 221, Nanocrystalline silicon oxide layer; 230, First transparent conductive oxide layer; 240, Metal layer; 250, Long-wavelength reflective layer; 260, Electron transport layer; 270, Perovskite light-absorbing layer; 280, Hole transport layer; 290, First electrode; 310. Second intrinsic amorphous silicon layer; 320. Second doped layer; 321. First microcrystalline silicon oxycarbide layer; 322. Second microcrystalline silicon oxycarbide layer; 323. Third microcrystalline silicon oxycarbide layer; 330. Second transparent conductive oxide layer; 340. Second electrode. Detailed Implementation
[0023] The embodiments of this application are described in detail below, with examples of the embodiments illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, and elements, as well as their relative dimensions, may be exaggerated. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0024] like Figures 1 to 2 As shown, this application provides a solar cell, including: A silicon substrate 100 has a light-incident surface and a back-light surface disposed opposite to each other. A first intrinsic amorphous silicon layer 210 and a first doped layer 220 are sequentially stacked on the light-incident surface and along the direction away from the silicon substrate 100; wherein, the first doped layer 220 includes a nanocrystalline silicon oxide layer 221. A second intrinsic amorphous silicon layer 310, a second doped layer 320, and a second transparent conductive oxide layer 330 are sequentially stacked on the backlight surface along the direction away from the silicon substrate 100; wherein, the second doped layer 320 includes a first microcrystalline silicon carbide layer 321, a second microcrystalline silicon carbide layer 322, and a third microcrystalline silicon carbide layer 323 sequentially stacked along the direction away from the silicon substrate 100, and the carbon-oxygen ratio of the first microcrystalline silicon carbide layer 321, the second microcrystalline silicon carbide layer 322, and the third microcrystalline silicon carbide layer 323 decreases sequentially; The first doped layer 220 and the second doped layer 320 have different doping types.
[0025] The doped layer (i.e., the first doped layer) disposed on the light-incident surface of the silicon substrate includes a nanocrystalline silicon oxide layer (nc-SiO). x H-layer), wide-bandgap nc-SiO xH can reduce parasitic absorption, allowing more photons to be effectively absorbed and utilized, thereby improving the photoelectric conversion efficiency of solar cells; at the same time, well-crystallized nc-SiO x The presence of H facilitates the migration of charge carriers (such as electrons and holes), thereby reducing scattering and recombination losses during carrier transport. This allows charge carriers to reach the electrodes more efficiently, improving the current density and efficiency of the battery. Simultaneously, the doped layer (i.e., the second doped layer) on the back surface of the silicon substrate comprises a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, and a third microcrystalline silicon carbide layer. The optical and electrical properties of the microcrystalline silicon carbide layer are primarily influenced by the incorporation ratios of oxygen atoms, carbon atoms, and dopant atoms (e.g., phosphorus atoms). The carbon-oxygen ratio decreases sequentially from the first to the third microcrystalline silicon carbide layer, altering the electronic structure of these three silicon carbide (SiCO) layers, particularly the conduction band position. This sequentially lower conduction band position creates a gradient internal electric field, constructing a gradient-doped band structure that facilitates carrier migration and promotes improved battery efficiency. Meanwhile, adjusting the band structure can match the energy levels of the third microcrystalline silicon dioxide layer and the second transparent conductive oxide layer (TCO layer), thereby reducing the Schottky barrier between the second doped layer and the second TCO layer, effectively reducing the contact resistance and improving the fill factor of the battery.
[0026] The first and second doped layers have different doping types. When the first doped layer is an N-type doped layer, the second doped layer is a P-type doped layer; conversely, when the first doped layer is a P-type doped layer, the second doped layer is an N-type doped layer. The silicon substrate can be an N-type silicon substrate, a P-type silicon substrate, or a CZ-type silicon substrate. Specifically, the N-type silicon substrate is an N-type single-crystal silicon substrate (e.g., with a crystal phase of...). <100> or <111> The P-type silicon substrate is a P-type single-crystal silicon substrate (e.g., with a crystal phase of...). <100> or <111> ).
[0027] In some embodiments, the carbon-to-oxygen ratio of the first microcrystalline silicon dioxide layer is 0.6-0.8, the carbon-to-oxygen ratio of the second microcrystalline silicon dioxide layer is 0.4-0.6, and the carbon-to-oxygen ratio of the third microcrystalline silicon dioxide layer is 0.2-0.4.
[0028] The third microcrystalline silicon dioxide layer has a low carbon content. Introducing an appropriate amount of carbon can raise the conduction band bottom, making it closer to the conduction band of the TCO material, which helps improve the migration efficiency of charge carriers. When the carbon-to-oxygen ratio of the third microcrystalline silicon dioxide layer is 0.2-0.4, it can match the energy levels of the second TCO layer well, making the conduction band positions close, further improving the carrier mobility and reducing the contact resistance. In some embodiments, the carbon-to-oxygen ratio of the first microcrystalline silicon dioxide layer can be 0.65-0.8, specifically 0.65, 0.7, 0.75, or 0.8. In some embodiments, the carbon-to-oxygen ratio of the second microcrystalline silicon dioxide layer can be 0.45-0.6, specifically 0.45, 0.5, 0.55, or 0.6. In some embodiments, the carbon-to-oxygen ratio of the third microcrystalline silicon dioxide layer can be 0.25-0.4, specifically 0.25, 0.3, 0.35, or 0.4.
[0029] In some embodiments, the crystallinity of the first microcrystalline silicon carbide layer is 30%-40%, the crystallinity of the second microcrystalline silicon carbide layer is 15%-25%, and the crystallinity of the third microcrystalline silicon carbide layer is 35%-45%.
[0030] The crystallinity of the first and third microcrystalline silicon carbide layers is higher than that of the second microcrystalline silicon carbide layer. This is beneficial for the second doped layer to have good conductivity and light transmittance, while reducing interface state density and contact resistance. Simultaneously, the second microcrystalline silicon carbide layer, with its lower crystallinity, can provide more effective surface passivation, reducing surface trapped states and dangling bonds, thereby lowering the surface recombination rate. In some embodiments, the crystallinity of the first microcrystalline silicon carbide layer can be 30%, 35%, or 40%, the crystallinity of the second microcrystalline silicon carbide layer can be 15%, 20%, or 25%, and the crystallinity of the third microcrystalline silicon carbide layer can be 35%, 40%, or 45%.
[0031] In some embodiments, the first doped layer is a P-type doped layer and the second doped layer is an N-type doped layer; The ratio of carbon, oxygen, and phosphorus in the first microcrystalline silicon carbide layer is (0.6-0.7):1:(0.01-0.025), the ratio of carbon, oxygen, and phosphorus in the second microcrystalline silicon carbide layer is (0.45-0.55):1:(0.025-0.045), and the ratio of carbon, oxygen, and phosphorus in the third microcrystalline silicon carbide layer is (0.2-0.3):1:(0.045-0.06).
[0032] The first microcrystalline silicon oxide layer has a low phosphorus content, which can prevent damage to the passivation effect of the adjacent intrinsic amorphous silicon layer (the second intrinsic amorphous silicon layer), ensuring that the second intrinsic amorphous silicon layer has a high passivation effect; the second microcrystalline silicon oxide layer has a slightly higher phosphorus content, which makes the entire three-layer structure maintain a relatively smooth transition and can reduce the interface effect between thin films. In some embodiments, the ratio of carbon, oxygen, and phosphorus in the first microcrystalline silicon carbide layer can be (0.6-0.7):1:(0.01-0.02), specifically 0.6:1:0.01, 0.65:1:0.01, 0.7:1:0.01, 0.6:1:0.015, 0.65:1:0.015, 0.7:1:0.015, 0.6:1:0.02, 0.65:1:0.02, 0.7:1:0.02, 0.6:1:0.025, 0.65:1:0.025, or 0.7:1:0.025. In some embodiments, the ratio of carbon, oxygen, and phosphorus in the second microcrystalline silicon carbide layer can be (0.45-0.55):1:(0.025-0.04), specifically 0.45:1:0.025, 0.5:1:0.025, 0.55:1:0.025, 0.45:1:0.03, 0.5:1:0.03, 0.55:1:0.03, 0.45:1:0.035, 0.5:1:0.035, 0.55:1:0.035, 0.45:1:0.04, 0.5:1:0.04, 0.55:1:0.04, 0.45:1:0.045, 0.5:1:0.045, or 0.55:1:0.045. In some embodiments, the ratio of carbon, oxygen, and phosphorus in the third microcrystalline silicon carbide layer can be (0.2-0.3):1:(0.05-0.06), specifically 0.2:1:0.045, 0.25:1:0.045, 0.3:1:0.045, 0.2:1:0.05, 0.25:1:0.05, 0.3:1:0.05, 0.2:1:0.055, 0.25:1:0.055, 0.3:1:0.055, 0.2:1:0.06, 0.25:1:0.06, or 0.3:1:0.06.
[0033] In some embodiments, the thicknesses of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer are each and independently 1-15 nm.
[0034] When the thicknesses of these three layers are 1-15 nm, each layer has sufficient thickness to ensure a relatively smooth transition between adjacent layers with different structures, thereby reducing the interface effect between thin films. In optional embodiments, the thicknesses of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer can be 1 nm, 3 nm, 5 nm, 8 nm, 10 nm, 12 nm, or 15 nm, respectively and independently.
[0035] In some embodiments, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.5-2; and / or The crystallinity of the nanocrystalline silicon oxide layer is greater than or equal to 25%.
[0036] When the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.5–2 or the crystallinity is greater than or equal to 25%, the nanocrystalline silicon oxide layer exhibits good electrical conductivity, which can reach 2 × 10⁻⁶. -2 -5×10 -2 The silicon-to-oxygen ratio (S / cm) of the nanocrystalline silicon oxide layer is increased to improve the photoelectric conversion efficiency of the battery. In optional embodiments, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer can be 1.5, 1.7, 1.8, or 2. In optional embodiments, the crystallinity of the nanocrystalline silicon oxide layer can be 25%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.
[0037] In some embodiments, the first doped layer is a P-type doped layer and the second doped layer is an N-type doped layer; The boron doping concentration in the nanocrystalline silicon oxide layer is 1×10⁻⁶. 19 -1×10 21 atom / cm 3 .
[0038] When the boron doping concentration in the nanocrystalline silicon oxide layer is 1×10 19 -1×10 21 atom / cm 3 This can enhance the conductivity of the nanocrystalline silicon oxide layer, giving the first doped layer good electrical conductivity and thus improving the photoelectric conversion efficiency of the solar cell.
[0039] In an optional embodiment, the thickness of the nanocrystalline silicon oxide layer is 20-100 nm. When the thickness of the nanocrystalline silicon oxide layer is 20-100 nm, it not only has a good passivation effect, but also protects the HJT battery in subsequent operations.
[0040] like Figure 1 and Figure 2 As shown, in some embodiments, the solar cell further includes: A first transparent conductive oxide layer 230 and a first electrode 290 are sequentially stacked on the first doped layer 220 and along the direction away from the silicon substrate 100; The second electrode 340 is located on the side of the second transparent conductive oxide layer 330 away from the silicon substrate 100.
[0041] In some embodiments, the first transparent conductive oxide layer includes MoO x TeO x One or two of them.
[0042] MoO x / TeO x As an optical coupling layer, it has a low refractive index and can act as a buffer layer to reduce the refractive index difference between the metal layer and the silicon-based material, thereby reducing reflection loss.
[0043] like Figure 2 As shown, in some embodiments, the solar cell further includes: The metal layer 240, long-wave reflective layer 250, electron transport layer 260, perovskite light-absorbing layer 270 and hole transport layer 280 are sequentially stacked between the first transparent conductive oxide layer 230 and the first electrode 290 and along the direction away from the silicon substrate 100. The metal layer 240 has a thickness of 5-10 nm, and the second electrode 340 is a metal electrode with a thickness of 50-200 nm.
[0044] In this embodiment, a long-wavelength reflective layer is provided on the back of the perovskite light-absorbing layer. Long-wavelength sunlight that is not absorbed by the perovskite light-absorbing layer is reflected by the long-wavelength reflective layer and re-enters the perovskite light-absorbing layer, where it is fully absorbed, thereby increasing light absorption and the generation of photogenerated carriers, and improving the photoelectric conversion efficiency of the solar cell.
[0045] Under illumination, the metal layer has a thickness of 5-10 nm, which is considered an ultrathin metal layer. This thickness is conducive to the generation of plasmon resonance. When the incident light matches the resonant wavelength of the plasmons, the plasmons are excited, thereby generating a strong local electric field on the metal surface. This local electric field can effectively promote the coupling of incident light into the microcavity structure composed of a first doped layer, a first intrinsic amorphous silicon layer, a silicon substrate, a second intrinsic amorphous silicon layer, and a second doped layer, thus enhancing light absorption.
[0046] In some embodiments, the metal layer can be made of one or more of Ag, Au, and Al. These metal materials are all mirror-finish metal materials, which can enhance interference resonance in the microcavity structure and improve the conductivity of the metal layer, reduce series resistance, and facilitate the use of the battery in large-area devices. Since light can pass through the metal layer to enter the device, the electrode should also have relatively high transmittance in visible light so that more light can reach the active layer, achieving a balance between the reflectivity and transmittance of the metal layer. Considering conductivity, absorption in the visible light region, and cost-effectiveness, the metal layer material can be Ag.
[0047] The second electrode is a metal electrode with a thickness of 50-200 nm. It is an opaque, dense metal electrode. This dense metal electrode can not only effectively conduct current but also act as a reflective layer, reflecting unabsorbed light passing through the photovoltaic material back into the battery. This increases the path length of photons in the active material, thereby further improving the light absorption rate and the overall efficiency of the battery. In some embodiments, the material of the second electrode can be Ag.
[0048] In some embodiments, the long-wavelength reflective layer includes one or both of ZnO and SrTiO3.
[0049] ZnO and SrTiO3 have specific crystal structures and lattice vibration modes, which give them a good response to long wavelengths and enable them to effectively reflect long wavelengths. In addition, ZnO and SrTiO3 are wide bandgap semiconductor materials, which have high transmittance in the visible light region and can effectively reflect long-wave radiation in the near-infrared region because of their high refractive index.
[0050] In optional embodiments, the solar cell further includes an antireflection layer located on the side of the hole transport layer away from the silicon substrate, wherein the first electrode is an electrode grid line, and the antireflection layer does not cover the electrode grid line. In optional embodiments, the material of the antireflection layer includes, but is not limited to, magnesium fluoride (MgF2), aluminum oxide (Al2O3), zirconium dioxide (ZrO2), and silicon nitride (SiN). x One or more of the following: indium tin oxide (ITO) or tin-doped indium oxide (ITO).
[0051] In an optional embodiment, the perovskite material has a three-dimensional structure, the general formula of which may be: ABX3; wherein A is a monovalent cation, including but not limited to cesium ions (Cs). + ), rubidium ions (Rb + ), methylamino cation (CH3NH3) + ), formamidinyl cation (CH2(NH2)2) + A mixture of one or more of the following: B is a divalent cation, including but not limited to lead ions (Pb). 2+ ), copper ions (Cu) 2+), zinc ions (Zn 2+ Gallium ions (Ga) 2+ ), tin ions (Sn) 2+ ), calcium ions (Ca 2+ X is one or more of the following mixtures; X is a monovalent anion, including but not limited to iodide ions (I2). - ), bromide ions (Br) - ), chloride ions (Cl) - ), fluoride ions (F) - ), thiocyanate ion (SCN) - One or more of the following mixtures.
[0052] In optional embodiments, the hole transport layer material includes, but is not limited to, one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz).
[0053] In optional embodiments, the materials of the electron transport layer include, but are not limited to, TiO2, SnO2, ZnO, ZrO2, gallium zinc oxide (GZO), indium zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium tin oxide (ITO), BaSnO3, and TiSnO. x SnZnO x One or more of the following: fullerene, fullerene derivatives, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).
[0054] In optional embodiments, the material of the second transparent conductive oxide layer includes, but is not limited to, one or more of the following: indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), indium molybdenum oxide (IMO), fluorine-doped tin oxide (FTO), indium cerium oxide (ICO), aluminum-doped zinc oxide (AZO), antimony-doped tin oxide (ATO), boron-doped zinc oxide (BZO), and VTTO; wherein the composition of VTTO is In2O3:ZrO2:TiO2:Ga2O3 in a mass ratio of 98.5:0.5:0.5:0.5.
[0055] In optional embodiments, the material of the first electrode includes, but is not limited to, one or more of Au, Ag, Al, Cu, transparent conductive oxide (TCO), graphene, and nanocrystalline silicon.
[0056] This application also provides a method for preparing a solar cell, comprising: A silicon substrate is provided, the silicon substrate having a light-incident surface and a back-light surface disposed opposite to each other; A first intrinsic amorphous silicon layer and a first doped layer are sequentially formed on the light-incident surface; wherein, the first doped layer includes a nanocrystalline silicon oxide layer; A second intrinsic amorphous silicon layer, a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, a third microcrystalline silicon carbide layer, and a second transparent conductive oxide layer are sequentially formed on the backlight surface; wherein, the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer together constitute the second doped layer, and the carbon-oxygen ratio of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer decreases sequentially; The first doped layer and the second doped layer have different doping types.
[0057] In some embodiments, the method for preparing a nanocrystalline silicon oxide layer includes: A plasma-enhanced chemical vapor deposition (PECVD) device is used to form a nanocrystalline silicon oxide layer on a first intrinsic amorphous silicon layer using hydrogen, silane, borane, and carbon dioxide gases. The flow rate of silane in the reaction gases is 0.1-3%, the flow rate ratio of borane to silane is 0.001-0.05, and the flow rate ratio of carbon dioxide to silane is 0.1-7.
[0058] In some embodiments, during the fabrication of the nanocrystalline silicon oxide layer, the glow discharge excitation frequency of the PECVD equipment is 15-100MHz, and the glow discharge power density is 20-1000mW / cm². 2 The reaction gas pressure is 0.1-10 Torr, and the reaction temperature is 100-250℃.
[0059] In some embodiments, a plasma-enhanced chemical vapor deposition (PECVD) apparatus is used to form a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, and a third microcrystalline silicon carbide layer using hydrogen, silane, phosphine, and carbon dioxide gases, wherein the gas flow ratio of hydrogen to silane is 25-300, the gas flow ratio of phosphine to silane is 0.05-0.15, and the gas flow ratio of carbon dioxide to silane is 0.5-5.
[0060] In some embodiments, the method for preparing the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer includes: A plasma-enhanced chemical vapor deposition (PECVD) device was used to form a first microcrystalline silicon oxide layer on a second intrinsic amorphous silicon layer using hydrogen, silane, phosphine, and carbon dioxide gases; wherein the gas flow ratio of hydrogen to silane was 181-300, the gas flow ratio of phosphine to silane was 0.05-0.074, and the gas flow ratio of carbon dioxide to silane was 3.9-5. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 121-180, the gas flow rate ratio of phosphine to silane was 0.075-0.11, and the gas flow rate ratio of carbon dioxide to silane was 1.7-3.8. The PECVD equipment is continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide are adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane is 25-120, the gas flow rate ratio of phosphine to silane is 0.12-0.15, and the gas flow rate ratio of carbon dioxide to silane is 0.5-1.6.
[0061] In some embodiments, during the fabrication of the first, second, and third microcrystalline silicon carbide layers, the power density of the PECVD equipment is 10 mW / cm². 2 -100mW / cm 2 The deposition pressure is 50Pa-500Pa, and the deposition temperature is 100℃-300℃.
[0062] In some embodiments, the method for preparing a solar cell further includes: A first transparent conductive oxide layer and a first electrode are sequentially formed on the side of the first doped layer away from the silicon substrate; A second electrode is formed on the side of the second transparent conductive oxide layer away from the silicon substrate.
[0063] In some embodiments, the method for preparing a solar cell further includes: Between the first transparent conductive oxide layer and the first electrode, and along the direction away from the silicon substrate, a metal layer, a long-wavelength reflective layer, an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer are formed sequentially.
[0064] The following specific embodiments provide a more detailed description of this application, but should not be construed as limiting the application. Any modifications or substitutions made to the methods, steps, or conditions of this application without departing from the spirit and substance of this application are within the scope of this application.
[0065] Example 1 like Figure 1 As shown, the structure of the solar cell in Example 1 includes: Silicon substrate 100 (N-type silicon substrate), the silicon substrate 100 includes a light-incident surface and a back-light surface disposed opposite to each other; A first intrinsic amorphous silicon layer 210, a first doped layer 220, a first transparent conductive oxide layer 230, and a first electrode 290 are sequentially stacked on the light-incident surface along the direction away from the silicon substrate 100; wherein, the first doped layer 220 includes a nanocrystalline silicon oxide layer 221, and the first doped layer 220 is a P-type doped layer. A second intrinsic amorphous silicon layer 310, a second doped layer 320, a second transparent conductive oxide layer 330, and a second electrode 340 are sequentially stacked on the backlight surface along the direction away from the silicon substrate 100; wherein, the second doped layer 320 includes a first microcrystalline silicon oxide layer 321, a second microcrystalline silicon oxide layer 322, and a third microcrystalline silicon oxide layer 323 sequentially stacked along the direction away from the silicon substrate 100, and the second doped layer 320 is an N-type doped layer; The nanocrystalline silicon oxide layer has a silicon-to-oxygen ratio of 1.8, a crystallinity of 50%, and a boron doping concentration of 5 × 10⁻⁶. 19 atom / cm 3 The thickness is 40nm; The first microcrystalline silicon dioxide layer has a crystallinity of 35%, a carbon, oxygen, and phosphorus ratio of 0.65:1:0.02, and a thickness of 8 nm. The second microcrystalline silicon dioxide layer has a crystallinity of 20%, a carbon, oxygen, and phosphorus ratio of 0.5:1:0.03, and a thickness of 8 nm. The third microcrystalline silicon dioxide layer has a crystallization rate of 40%, a carbon, oxygen, and phosphorus ratio of 0.25:1:0.05, and a thickness of 8 nm.
[0066] The method for preparing a solar cell in Example 1 includes: Step S110: Provide a silicon substrate (N-type silicon substrate), the silicon substrate including a light-incident surface and a back-light surface disposed opposite to each other; Step S120: Form a first intrinsic amorphous silicon layer on the light-incident surface; A second intrinsic amorphous silicon layer is formed on the backlight surface; Step S130: Using a plasma-enhanced chemical vapor deposition (PECVD) device, a nanocrystalline silicon oxide layer is formed on the first intrinsic amorphous silicon layer by hydrogen, silane, borane, and carbon dioxide gases; wherein, the gas flow rate of silane in the reaction gas is 1.5%, the gas flow rate ratio of borane to silane is 0.04, and the gas flow rate ratio of carbon dioxide to silane is 5. Step S140: Using a plasma-enhanced chemical vapor deposition (PECVD) device, hydrogen, silane, phosphine, and carbon dioxide gases are used to form a first microcrystalline silicon oxide layer on the second intrinsic amorphous silicon layer; wherein the gas flow ratio of hydrogen to silane is 200, the gas flow ratio of phosphine to silane is 0.055, and the gas flow ratio of carbon dioxide to silane is 4.5. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 160, the gas flow rate ratio of phosphine to silane was 0.09, and the gas flow rate ratio of carbon dioxide to silane was 2.3. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 95, the gas flow rate ratio of phosphine to silane was 0.14, and the gas flow rate ratio of carbon dioxide to silane was 0.9. Step S150: Form a first transparent conductive oxide layer on the nanocrystalline silicon oxide layer; A second transparent conductive oxide layer is formed on the third microcrystalline silicon dioxide layer; Step S160: Form a first electrode on the first transparent conductive oxide layer; A second electrode is formed on the second transparent conductive oxide layer.
[0067] Example 2 The structure of the solar cell in Example 2 is similar to that of the solar cell in Example 1, except that in the solar cell of Example 2, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.5, the crystallinity is 35%, and the boron doping concentration is 1×10⁻⁶. 20 atom / cm 3 The thickness is 80nm; The first microcrystalline silicon dioxide layer has a crystallization rate of 30%, a carbon, oxygen, and phosphorus ratio of 0.7:1:0.015, and a thickness of 10 nm. The second microcrystalline silicon dioxide layer has a crystallinity of 20%, a carbon, oxygen, and phosphorus ratio of 0.55:1:0.04, and a thickness of 10 nm. The third microcrystalline silicon dioxide layer has a crystallization rate of 45%, a carbon, oxygen, and phosphorus ratio of 0.3:1:0.055, and a thickness of 10 nm.
[0068] The method for preparing the solar cell in Example 2 is similar to that in Example 1, except that in the method for preparing the solar cell in Example 2, Step S130 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, a nanocrystalline silicon oxide layer is formed on the first intrinsic amorphous silicon layer by hydrogen, silane, borane and carbon dioxide gases; wherein, the gas flow rate of silane in the reaction gas is 2%, the gas flow rate ratio of borane to silane is 0.03, and the flow rate ratio of carbon dioxide to silane is 4. Step S140 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, hydrogen, silane, phosphine, and carbon dioxide gases are used to form a first microcrystalline silicon oxide layer on the second intrinsic amorphous silicon layer; wherein the gas flow ratio of hydrogen to silane is 230, the gas flow ratio of phosphine to silane is 0.07, and the gas flow ratio of carbon dioxide to silane is 4.8. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 170, the gas flow rate ratio of phosphine to silane was 0.10, and the gas flow rate ratio of carbon dioxide to silane was 3.2. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 110, the gas flow rate ratio of phosphine to silane was 0.15, and the gas flow rate ratio of carbon dioxide to silane was 1.4.
[0069] Example 3 The structure of the solar cell in Example 3 is similar to that of the solar cell in Example 1, except that in the solar cell of Example 3, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 2, the crystallinity is 65%, and the boron doping concentration is 5 × 10⁻⁶. 20 atom / cm 3 The thickness is 35nm; The first microcrystalline silicon dioxide layer has a crystallization rate of 30%, a carbon, oxygen, and phosphorus ratio of 0.65:1:0.025, and a thickness of 11 nm. The second microcrystalline silicon dioxide layer has a crystallization rate of 15%, a carbon, oxygen, and phosphorus ratio of 0.5:1:0.035, and a thickness of 11 nm. The third microcrystalline silicon dioxide layer has a crystallization rate of 35%, a carbon, oxygen, and phosphorus ratio of 0.3:1:0.045, and a thickness of 13 nm.
[0070] The method for preparing the solar cell in Example 3 is similar to that in Example 1, except that in the method for preparing the solar cell in Example 3, Step S130 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, a nanocrystalline silicon oxide layer is formed on the first intrinsic amorphous silicon layer by hydrogen, silane, borane and carbon dioxide gases; wherein, the gas flow rate of silane in the reaction gas is 2.5%, the gas flow rate ratio of borane to silane is 0.015, and the flow rate ratio of carbon dioxide to silane is 2.2. Step S140 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, hydrogen, silane, phosphine, and carbon dioxide gases are used to form a first microcrystalline silicon oxide layer on the second intrinsic amorphous silicon layer; wherein, the gas flow ratio of hydrogen to silane is 270, the gas flow ratio of phosphine to silane is 0.065, and the gas flow ratio of carbon dioxide to silane is 4. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 135, the gas flow rate ratio of phosphine to silane was 0.08, and the gas flow rate ratio of carbon dioxide to silane was 1.9. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 50, the gas flow rate ratio of phosphine to silane was 0.13, and the gas flow rate ratio of carbon dioxide to silane was 1.1.
[0071] Example 4 like Figure 2 As shown, the structure of the solar cell in Example 4 includes: Silicon substrate 100 (N-type silicon substrate), the silicon substrate 100 includes a light-incident surface and a back-light surface disposed opposite to each other; The light-receiving surface comprises, in sequence along the direction away from the silicon substrate 100, a first intrinsic amorphous silicon layer 210, a first doped layer 220, a first transparent conductive oxide layer 230, a metal layer 240, a long-wavelength reflective layer 250, an electron transport layer 260, a perovskite light-absorbing layer 270, a hole transport layer 280, and a first electrode 290; wherein, the first doped layer 220 includes a nanocrystalline silicon oxide layer 221, and the first doped layer 220 is a P-type doped layer; A second intrinsic amorphous silicon layer 310, a second doped layer 320, a second transparent conductive oxide layer 330, and a second electrode 340 are sequentially stacked on the backlight surface along the direction away from the silicon substrate 100; wherein, the second doped layer 320 includes a first microcrystalline silicon oxide layer 321, a second microcrystalline silicon oxide layer 322, and a third microcrystalline silicon oxide layer 323 sequentially stacked along the direction away from the silicon substrate 100, and the second doped layer 320 is an N-type doped layer; The nanocrystalline silicon oxide layer has a silicon-to-oxygen ratio of 1.9, a crystallinity of 45%, and a boron doping concentration of 3×10⁻⁶. 20 atom / cm 3 The thickness is 45nm; The first microcrystalline silicon dioxide layer has a crystallization rate of 40%, a carbon, oxygen, and phosphorus ratio of 0.7:1:0.02, and a thickness of 12 nm. The second microcrystalline silicon dioxide layer has a crystallinity of 25%, a carbon, oxygen, and phosphorus ratio of 0.5:1:0.04, and a thickness of 10 nm. The third microcrystalline silicon dioxide layer has a crystallinity of 35%, a carbon, oxygen, and phosphorus ratio of 0.25:1:0.055, and a thickness of 8 nm. The first transparent conductive oxide layer includes MoO. x ; The metal layer is 8 nm thick and made of Ag. The second electrode has a thickness of 100 nm and is made of Ag. The long-wave reflective layer includes ZnO and SrTiO3.
[0072] The method for preparing the solar cell in Example 4 includes: Step S210: Provide a silicon substrate (N-type silicon substrate), the silicon substrate including a light-incident surface and a back-light surface disposed opposite to each other; Step S220: Form a first intrinsic amorphous silicon layer on the incident light surface; A second intrinsic amorphous silicon layer is formed on the backlight surface; Step S230: Using a plasma-enhanced chemical vapor deposition (PECVD) device, a nanocrystalline silicon oxide layer is formed on the first intrinsic amorphous silicon layer by hydrogen, silane, borane, and carbon dioxide gases; wherein, the gas flow rate of silane in the reaction gas is 2%, the gas flow rate ratio of borane to silane is 0.03, and the flow rate ratio of carbon dioxide to silane is 3.5. Step S240: Using a plasma-enhanced chemical vapor deposition (PECVD) device, hydrogen, silane, phosphine, and carbon dioxide gases are used to form a first microcrystalline silicon oxide layer on the second intrinsic amorphous silicon layer; wherein the gas flow ratio of hydrogen to silane is 240, the gas flow ratio of phosphine to silane is 0.06, and the gas flow ratio of carbon dioxide to silane is 4.5. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 150, the gas flow rate ratio of phosphine to silane was 0.09, and the gas flow rate ratio of carbon dioxide to silane was 2.6. The PECVD equipment was continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide were adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane was 80, the gas flow rate ratio of phosphine to silane was 0.13, and the gas flow rate ratio of carbon dioxide to silane was 1.0. Step S250: Form a first transparent conductive oxide layer on the nanocrystalline silicon oxide layer; A second transparent conductive oxide layer is formed on the third microcrystalline silicon dioxide layer; Step S260: A metal layer, a long-wavelength reflective layer, an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer are sequentially formed on the first transparent conductive oxide layer; Step S270: Form a first electrode on the hole transport layer; A second electrode is formed on the second transparent conductive oxide layer.
[0073] Example 5 The structure of the solar cell in Example 5 is similar to that of the solar cell in Example 4, except that in the solar cell of Example 5, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.6, the crystallinity is 45%, and the boron doping concentration is 8 × 10⁻⁶. 19 atom / cm 3 The thickness is 60nm; The first microcrystalline silicon dioxide layer has a crystallinity of 30%, a carbon, oxygen, and phosphorus ratio of 0.65:1:0.015, and a thickness of 6 nm. The second microcrystalline silicon dioxide layer has a crystallinity of 20%, a carbon, oxygen, and phosphorus ratio of 0.5:1:0.03, and a thickness of 9 nm. The third microcrystalline silicon dioxide layer has a crystallinity of 35%, a carbon, oxygen, and phosphorus ratio of 0.3:1:0.055, and a thickness of 11 nm. The first transparent conductive oxide layer includes MoO. x and TeO x .
[0074] The metal layer is 8 nm thick and made of Ag. The thickness of the second electrode is 150 nm, and the material is Ag. The long-wave reflective layer includes ZnO and SrTiO3.
[0075] Example 6 The structure of the solar cell in Example 6 is similar to that of the solar cell in Example 4, except that in the solar cell of Example 6, the silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.8, the crystallinity is 55%, and the boron doping concentration is 1×10⁻⁶. 21 atom / cm 3 The thickness is 85nm; The first microcrystalline silicon dioxide layer has a crystallinity of 40%, a carbon, oxygen, and phosphorus ratio of 0.6:1:0.025, and a thickness of 10 nm. The second microcrystalline silicon dioxide layer has a crystallinity of 20%, a carbon, oxygen, and phosphorus ratio of 0.55:1:0.03, and a thickness of 10 nm. The third microcrystalline silicon dioxide layer has a crystallinity of 45%, a carbon, oxygen, and phosphorus ratio of 0.25:1:0.055, and a thickness of 10 nm. The first transparent conductive oxide layer includes MoO. x and TeO x ; The metal layer is 10 nm thick and made of Ag. The thickness of the second electrode is 120 nm, and the material is Ag. The long-wave reflective layer includes ZnO and SrTiO3.
[0076] To more clearly illustrate the technical effects of the embodiments of this application, this application also points out the specific structure and preparation method of the solar cells of Comparative Example 1 and Comparative Example 2.
[0077] Comparative Example 1 The structure of the solar cell in Comparative Example 1 is similar to that of the solar cell in Example 1, except that in the solar cell of Comparative Example 1, the first doped layer is a P-type polycrystalline silicon doped layer and does not have a nanocrystalline silicon oxide layer; the second doped layer is an N-type polycrystalline silicon doped layer and does not have a first microcrystalline silicon oxide layer, a second microcrystalline silicon oxide layer and a third microcrystalline silicon oxide layer.
[0078] The solar cell of Comparative Example 1 was prepared using a similar method to that of Example 1, except that the preparation method of the solar cell of Comparative Example 1... Step S130 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, a P-type polycrystalline silicon doped layer is formed on the first intrinsic amorphous silicon layer by hydrogen, silane, and borane gases; wherein, the gas flow rate of silane in the reaction gas is 2.5%, and the gas flow rate ratio of borane to silane is 0.015; Step S140 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, an N-type polycrystalline silicon doped layer is formed on the second intrinsic amorphous silicon layer by hydrogen, silane and phosphine gases; wherein the gas flow rate ratio of hydrogen to silane is 270, and the gas flow rate ratio of phosphine to silane is 0.065.
[0079] Comparative Example 2 The structure of the solar cell in Comparative Example 2 is similar to that of the solar cell in Example 4, except that in the solar cell of Comparative Example 2, the first doped layer is a P-type polycrystalline silicon doped layer and does not have a nanocrystalline silicon oxide layer; the second doped layer is an N-type polycrystalline silicon doped layer and does not have a first microcrystalline silicon oxide layer, a second microcrystalline silicon oxide layer, and a third microcrystalline silicon oxide layer.
[0080] The solar cell of Comparative Example 2 was prepared using a similar method to that of Example 4, except that the preparation method of the solar cell of Comparative Example 2... Step S230 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, a P-type polycrystalline silicon doped layer is formed on the first intrinsic amorphous silicon layer by hydrogen, silane, and borane gases; wherein, the gas flow rate of silane in the reaction gas is 2.5%, and the gas flow rate ratio of borane to silane is 0.015; Step S240 is as follows: using a plasma-enhanced chemical vapor deposition (PECVD) device, an N-type polycrystalline silicon doped layer is formed on the second intrinsic amorphous silicon layer by hydrogen, silane and phosphine gases; wherein the gas flow rate ratio of hydrogen to silane is 270, and the gas flow rate ratio of phosphine to silane is 0.065.
[0081] In this application, the solar cells (210×105mm cells) in Examples 1 to 6 and Comparative Examples 1 to 2 were respectively made into corresponding photovoltaic modules, and performance tests were conducted to obtain the conversion efficiency Eff, short-circuit current Isc, open-circuit voltage Voc, and fill factor FF of the corresponding photovoltaic modules. The relevant test results are shown in Table 1.
[0082] Table 1
[0083] As can be seen from the data in Table 1, compared with Comparative Example 1 and Comparative Example 2, the photovoltaic modules made from the solar cells of Examples 1 to 6 of this application have significantly improved conversion efficiency, short-circuit current, open-circuit voltage and fill factor.
[0084] In summary, in the embodiments of this application, the doped layer (i.e., the first doped layer) disposed on the light-incident surface of the silicon substrate includes a nanocrystalline silicon oxide layer (nc-SiO). x H-layer), wide-bandgap nc-SiO x H can reduce parasitic absorption, allowing more photons to be effectively absorbed and utilized, thereby improving the photoelectric conversion efficiency of solar cells; at the same time, well-crystallized nc-SiO xThe presence of H facilitates the migration of charge carriers (such as electrons and holes), thereby reducing scattering and recombination losses during carrier transport. This allows charge carriers to reach the electrodes more efficiently, improving the current density and efficiency of the battery. Simultaneously, the doped layer (i.e., the second doped layer) on the back surface of the silicon substrate comprises a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, and a third microcrystalline silicon carbide layer. The optical and electrical properties of the microcrystalline silicon carbide layer are primarily influenced by the incorporation ratios of oxygen atoms, carbon atoms, and dopant atoms (e.g., phosphorus atoms). The carbon-oxygen ratio decreases sequentially from the first to the third microcrystalline silicon carbide layer, altering the electronic structure of these three silicon carbide (SiCO) layers, particularly the conduction band position. This sequentially lower conduction band position creates a gradient internal electric field, constructing a gradient-doped band structure that facilitates carrier migration and promotes improved battery efficiency. Meanwhile, adjusting the band structure can match the energy levels of the third microcrystalline silicon dioxide layer and the second transparent conductive oxide layer (TCO layer), thereby reducing the Schottky barrier between the second doped layer and the second TCO layer, effectively reducing the contact resistance and improving the fill factor of the battery.
[0085] It should be noted that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of the component itself. For example, if the device in the drawings is inverted, a device described as "above" or "on top of other devices or structures" will later be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.
[0086] 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 terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus 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, methods, products, or apparatus.
[0087] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in conjunction with that embodiment, which are included in at least one embodiment described in the general description of this application. The above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural modifications made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.
Claims
1. A solar cell, characterized in that, include: A silicon substrate having a light-incident surface and a back-light surface disposed opposite to each other; A first intrinsic amorphous silicon layer and a first doped layer are sequentially stacked on the light-incident surface and along the direction away from the silicon substrate; wherein, the first doped layer includes a nanocrystalline silicon oxide layer; A second intrinsic amorphous silicon layer, a second doped layer, and a second transparent conductive oxide layer are sequentially stacked on the backlight surface and along the direction away from the silicon substrate; wherein, the second doped layer includes a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, and a third microcrystalline silicon carbide layer sequentially stacked along the direction away from the silicon substrate, and the carbon-oxygen ratio of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer decreases sequentially; The first doped layer and the second doped layer have different doping types.
2. The solar cell according to claim 1, characterized in that, The carbon-to-oxygen ratio of the first microcrystalline silicon dioxide layer is 0.6-0.8, the carbon-to-oxygen ratio of the second microcrystalline silicon dioxide layer is 0.4-0.6, and the carbon-to-oxygen ratio of the third microcrystalline silicon dioxide layer is 0.2-0.
4.
3. The solar cell according to claim 1, characterized in that, The crystallinity of the first microcrystalline silicon carbide layer is 30%-40%, the crystallinity of the second microcrystalline silicon carbide layer is 15%-25%, and the crystallinity of the third microcrystalline silicon carbide layer is 35%-45%.
4. The solar cell according to claim 1, characterized in that, The first doped layer is a P-type doped layer, and the second doped layer is an N-type doped layer; The ratio of carbon, oxygen, and phosphorus in the first microcrystalline silicon carbide layer is (0.6-0.7):1:(0.01-0.025), the ratio of carbon, oxygen, and phosphorus in the second microcrystalline silicon carbide layer is (0.45-0.55):1:(0.025-0.045), and the ratio of carbon, oxygen, and phosphorus in the third microcrystalline silicon carbide layer is (0.2-0.3):1:(0.045-0.06).
5. The solar cell according to claim 1, characterized in that, The thicknesses of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer are each 1-15 nm, and are independent of each other.
6. The solar cell according to claim 1, characterized in that, The silicon-to-oxygen ratio of the nanocrystalline silicon oxide layer is 1.5-2; and / or The crystallinity of the nanocrystalline silicon oxide layer is greater than or equal to 25%.
7. The solar cell according to claim 1, characterized in that, The first doped layer is a P-type doped layer, and the second doped layer is an N-type doped layer; The boron doping concentration in the nanocrystalline silicon oxide layer is 1×10⁻⁶. 19 -1×10 21 atom / cm 3 .
8. The solar cell according to any one of claims 1 to 7, characterized in that, Also includes: A first transparent conductive oxide layer and a first electrode are sequentially stacked on the first doped layer in a direction away from the silicon substrate; The second electrode is located on the side of the second transparent conductive oxide layer away from the silicon substrate.
9. The solar cell according to claim 8, characterized in that, The first transparent conductive oxide layer includes MoO x TeO x One or two of them.
10. The solar cell according to claim 8, characterized in that, Also includes: Located between the first transparent conductive oxide layer and the first electrode, and stacked sequentially along the direction away from the silicon substrate are a metal layer, a long-wavelength reflective layer, an electron transport layer, a perovskite light-absorbing layer, and a hole transport layer. The thickness of the metal layer is 5-10 nm, and the second electrode is a metal electrode with a thickness of 50-200 nm.
11. The solar cell according to claim 10, characterized in that, The long-wave reflective layer includes one or both of ZnO and SrTiO3.
12. A method for preparing a solar cell, characterized in that, include: A silicon substrate is provided, the silicon substrate having a light-incident surface and a back-light surface disposed opposite to each other; A first intrinsic amorphous silicon layer and a first doped layer are sequentially formed on the light-incident surface; wherein, the first doped layer includes a nanocrystalline silicon oxide layer; A second intrinsic amorphous silicon layer, a first microcrystalline silicon carbide layer, a second microcrystalline silicon carbide layer, a third microcrystalline silicon carbide layer, and a second transparent conductive oxide layer are sequentially formed on the backlight surface; wherein, the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer together constitute a second doped layer, and the carbon-oxygen ratio of the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer decreases sequentially; The first doped layer and the second doped layer have different doping types.
13. The method for preparing a solar cell according to claim 12, characterized in that, The method for preparing the first microcrystalline silicon carbide layer, the second microcrystalline silicon carbide layer, and the third microcrystalline silicon carbide layer includes: A plasma-enhanced chemical vapor deposition (PECVD) device is used to form a first microcrystalline silicon oxide layer on a second intrinsic amorphous silicon layer using hydrogen, silane, phosphine, and carbon dioxide gases; wherein the gas flow ratio of hydrogen to silane is 181-300, the gas flow ratio of phosphine to silane is 0.05-0.074, and the gas flow ratio of carbon dioxide to silane is 3.9-5. The PECVD equipment is continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide are adjusted to form a second microcrystalline silicon carbide layer on the first microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane is 121-180, the gas flow rate ratio of phosphine to silane is 0.075-0.11, and the gas flow rate ratio of carbon dioxide to silane is 1.7-3.8; The PECVD equipment is continued, and the gas flow rates of hydrogen, silane, phosphine, and carbon dioxide are adjusted to form a third microcrystalline silicon carbide layer on the second microcrystalline silicon carbide layer; wherein the gas flow rate ratio of hydrogen to silane is 25-120, the gas flow rate ratio of phosphine to silane is 0.12-0.15, and the gas flow rate ratio of carbon dioxide to silane is 0.5-1.6.