Anti-ultraviolet irradiation crystalline silicon heterojunction solar cell and preparation method thereof

Abstract

The present application relates to a kind of anti-ultraviolet radiation crystalline silicon heterojunction solar cell and its preparation method, the crystalline silicon heterojunction solar cell includes: crystalline silicon substrate;First intrinsic amorphous silicon-based film, n-type doped silicon-based film, first TCO film, front metal gate are stacked to the first surface of crystalline silicon substrate;Second intrinsic amorphous silicon-based film, p-type doped silicon-based film, second TCO film, rear metal gate are stacked to the second surface of crystalline silicon substrate;The first, second surface is located at the opposite sides of crystalline silicon substrate respectively.The present application gives consideration to the anti-ultraviolet attenuation characteristic of ground crystalline silicon heterojunction solar cell and the anti-vacuum ultraviolet attenuation characteristic of space crystalline silicon heterojunction solar cell;TCO film under ultraviolet light irradiation download carrier concentration sharp enhancement, resistivity rapidly drop, work function drop adaptation with its near neighbor doped silicon-based film, can enhance the fill factor of solar cell, to enhance the anti-ultraviolet radiation stability of solar cell.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and specifically relates to a crystalline silicon heterojunction solar cell resistant to ultraviolet radiation and its preparation method. Background Technology

[0002] Solar cells are the sole energy source for the normal operation of low-Earth orbit satellites and space power stations, making them an indispensable and crucial component of spacecraft. Typical high-Earth orbit satellites utilize triple-junction gallium arsenide (GaAs) solar cells, achieving conversion efficiencies of around 30%-34% and exhibiting strong resistance to space radiation. However, the high complexity of integrating multi-component compound devices results in extremely high cell costs. The rapid development of mega-constellation satellite internet has created an urgent need for high-power, low-cost solar cells, making crystalline silicon solar cells a focus of attention. Currently, SpaceX satellites in the United States all use crystalline silicon solar cells. Due to the abundance of silicon-based materials and mature manufacturing processes, the cost of crystalline silicon solar cells is expected to be only about one-tenth that of gallium arsenide (GaAs).

[0003] Currently, the mainstream crystalline silicon solar cell technologies include Topcon, BC (back contact electrode), and HJT (heterojunction). Simulation studies have shown that P-type monocrystalline silicon heterojunction (HJT) solar cells significantly outperform other crystalline silicon technologies in space applications, making them the most suitable solar cells for low-Earth orbit (LEO) satellite applications. Ground-based crystalline silicon heterojunction (HJT) solar cell technology is very mature, with industrial-scale cell efficiencies reaching 25%-26%. However, when space-based crystalline silicon solar cells are operating in orbit, they are affected by ultraviolet radiation from the space environment, facing severe ultraviolet radiation degradation, which will seriously affect the normal operation of satellite payloads. Enhancing the ultraviolet radiation resistance of crystalline silicon solar cells is crucial for the stable supply of energy to LEO satellites. Summary of the Invention

[0004] The purpose of this invention is to provide a crystalline silicon heterojunction solar cell resistant to ultraviolet radiation and its preparation method, so as to solve the technical problem of decreased conversion efficiency of crystalline silicon heterojunction solar cells after ultraviolet radiation in the prior art.

[0005] This invention provides a crystalline silicon heterojunction solar cell resistant to ultraviolet radiation, comprising: a crystalline silicon substrate; a first intrinsic amorphous silicon thin film, an n-type doped silicon thin film, a first TCO (transparent conductive oxide) thin film, and a front metal gate stacked on a first surface of the crystalline silicon substrate; a second intrinsic amorphous silicon thin film, a p-type doped silicon thin film, a second TCO thin film, and a rear metal gate stacked on a second surface of the crystalline silicon substrate; the first surface and the second surface are respectively located on opposite sides of the crystalline silicon substrate.

[0006] Preferably, the crystalline silicon substrate is a monocrystalline silicon wafer or a polycrystalline silicon wafer, and the conductivity type is p-type, n-type or intrinsic type; depending on the process equipment configuration, preparation process and yield requirements, the thickness of the crystalline silicon substrate is 10-100 µm.

[0007] Preferably, the first and second intrinsic amorphous silicon-based thin films are hydrogenated amorphous silicon thin films or hydrogenated amorphous silicon oxide thin films, with a film thickness of 1-50 nm.

[0008] Preferably, the n-type or p-type doped silicon-based thin films are amorphous, microcrystalline, or amorphous / microcrystalline mixed structures; wherein the silicon-based thin films include silicon thin films or silicon-oxygen thin films, and the film thickness is 1-100 nm.

[0009] Furthermore, the material includes at least one of the following: n-type doped amorphous silicon thin film, n-type doped amorphous silicon oxide thin film, n-type doped microcrystalline silicon thin film, and n-type doped microcrystalline silicon oxide thin film.

[0010] Furthermore, the p-type doped silicon-based thin film includes at least one of p-type doped amorphous silicon thin film, p-type doped amorphous silicon oxide thin film, p-type doped microcrystalline silicon thin film, and p-type doped microcrystalline silicon oxide thin film.

[0011] Preferably, the first TCO film is a transparent conductive oxide containing indium or zinc or other conductive oxide material.

[0012] More preferably, the first TCO film is one or more of the following: zinc-doped indium oxide, tungsten-doped indium oxide, aluminum-doped zinc oxide, and indium oxide or zinc oxide co-doped with various cations. The band gap is adjustable between 3.0 and 3.8 eV. It has strong light absorption in the ultraviolet band (wavelength not exceeding 400 nm) and high transmittance in the visible and near-infrared bands.

[0013] Preferably, the second TCO film material is a narrow bandgap material that is the same as or different from the first TCO film, or a wide bandgap film material.

[0014] Preferably, the first and second TCO films can be single-layer films or multi-layer composite film structures with a thickness of 10-200 nm.

[0015] Preferably, the first TCO film has an amorphous structure and remains amorphous after ultraviolet irradiation; the second TCO film has an amorphous or polycrystalline structure and remains amorphous or polycrystalline after ultraviolet irradiation.

[0016] Preferably, the second TCO film has the same or different characteristics as the first TCO film.

[0017] Furthermore, the second TCO thin film can have near-infrared light strong reflection characteristics, which helps to improve the photoelectric conversion efficiency and output power of ultrathin crystalline silicon heterojunction solar cells and modules.

[0018] Preferably, the metal gate material is a metal material with good conductivity, including but not limited to one or more of Ag, Cu, Ag-coated Cu, Au, and Al.

[0019] This invention provides a method for fabricating a crystalline silicon heterojunction solar cell resistant to ultraviolet radiation, comprising the following steps:

[0020] S1. A crystalline silicon substrate is cleaned and texturized to obtain a surface structure with light-trapping properties;

[0021] S2. A first intrinsic amorphous silicon-based thin film and a second intrinsic amorphous silicon-based thin film are deposited on opposite sides of a texturized crystalline silicon substrate, respectively.

[0022] S3. Deposit an n-type doped silicon-based thin film on the first intrinsic amorphous silicon-based thin film, and deposit a p-type doped silicon-based thin film on the second intrinsic amorphous silicon-based thin film;

[0023] S4. A first TCO film resistant to ultraviolet radiation is deposited on an n-type doped silicon-based thin film to form a first light-receiving surface, and a second TCO film is deposited on a p-type doped silicon-based thin film to form a second light-receiving surface;

[0024] S5. A front metal gate and a back metal gate are fabricated on the first TCO thin film and the second TCO thin film, respectively, thereby completing the fabrication of a crystalline silicon heterojunction solar cell.

[0025] Preferably, step S1 specifically involves: preparing a light-trapping textured structure on the surface of a crystalline silicon substrate using a chemical wet process, and then performing chemical wet cleaning (e.g., cleaning using RCA1 and RCA2 solutions or oxidation methods).

[0026] Preferably, the average reflectivity of the crystalline silicon substrate described in step S1 after cleaning and texturing is between 1% and 30%.

[0027] Preferably, the first and second intrinsic amorphous silicon-based thin films in step S2 and the n-type and p-type doped silicon-based thin films in step S3 are prepared by plasma-enhanced chemical vapor deposition or hot-wire chemical vapor deposition.

[0028] Preferably, the preparation method of the first and second TCO thin films in step S4 includes at least one of magnetron sputtering, electron beam evaporation, physical vapor deposition, thermal evaporation and reactive plasma deposition, and the film deposition temperature does not exceed 250 °C.

[0029] Preferably, the preparation method of the front and rear metal gates in step S5 includes screen printing, electroplating, inkjet printing, etc.

[0030] This invention utilizes the narrow bandgap and strong ultraviolet absorption characteristics of the first TCO thin film on the first light-receiving surface to reduce the ultraviolet degradation characteristics of crystalline silicon heterojunction solar cells. By doping different types and amounts of elements into the indium oxide-based thin film, the bandgap of the TCO thin film can be adjusted between 3.0 and 3.8 eV. The narrow bandgap TCO thin film can efficiently absorb strong ultraviolet light. After the strong ultraviolet light is absorbed by the TCO, the electrical properties of the material change significantly. Moreover, the strong ultraviolet light will not enter the silicon-based thin film and disrupt the passivation and field effects of the silicon-based thin film, thereby significantly improving the ultraviolet degradation resistance of the crystalline silicon heterojunction.

[0031] Beneficial effects

[0032] (1) This invention utilizes the fact that the amorphous TCO thin film can significantly reduce resistivity and improve interface energy level matching after absorbing ultraviolet light to improve the conversion efficiency of the cell: The amorphous TCO thin film not only blocks high-energy ultraviolet light from entering the silicon-based thin film, but also uses high-energy photons to increase the concentration of photogenerated carriers on the amorphous TCO thin film, thereby reducing resistivity, work function and interface barrier, and significantly enhancing the fill factor and conversion efficiency of the solar cell. This has outstanding significance for the application of crystalline silicon heterojunction solar cells in low orbit space.

[0033] (2) This invention can be used to improve the problem of the decrease in power and power generation of photovoltaic modules caused by environmental ultraviolet radiation during the outdoor application of ground-based crystalline silicon heterojunction solar cells, and enhance their resistance to ultraviolet radiation. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the UV-resistant crystalline silicon heterojunction solar cell of the present invention.

[0035] Figure 2 The images show the XRD microstructures of the amorphous IZO film (narrow bandgap) and the control group ICO film (wide bandgap) before and after strong ultraviolet irradiation in Example 1 of this invention.

[0036] Figure 3 The transmittance and absorbance curves are shown for the IZO film (narrow bandgap) in Example 1 of this invention and the ICO film (wide bandgap) in the control group.

[0037] Figure 4 This refers to the change in light transmittance of the IZO film with oxygen flow rate in Example 1 of the present invention.

[0038] Figure 5 The variation of carrier concentration and resistivity of the IZO thin film with oxygen flow rate in Example 1 of this invention.

[0039] Figure 6 The changes in electrical characteristic parameters of the IZO thin film (narrow bandgap) and the control group ICO thin film (wide bandgap) before and after strong ultraviolet irradiation in Example 1 of this invention were measured using the Hall effect.

[0040] Figure 7 The work function changes of the IZO film (narrow bandgap) and the control group ICO film (wide bandgap) before and after strong ultraviolet irradiation in Example 1 of this invention are shown.

[0041] Figure 8 The figures show the external quantum efficiency curves of the first light-receiving surface crystalline silicon heterojunction solar cells based on IZO thin film (narrow bandgap) and control group ICO thin film (wide bandgap) in Example 1 of the present invention before and after strong ultraviolet irradiation.

[0042] Figure 9 The conversion efficiency (and / or maximum output power) of the first light-receiving surface crystalline silicon heterojunction solar cell based on IZO thin film (narrow bandgap) and control group ICO thin film (wide bandgap) in Example 1 of the present invention varies with ultraviolet irradiation intensity.

[0043] Reference numerals: 100-Crystal silicon substrate, 101-Front metal gate, 102-First TCO thin film, 103-n-type doped silicon-based thin film, 104-First intrinsic amorphous silicon-based thin film, 105-Second intrinsic amorphous silicon-based thin film, 106-p-type doped silicon-based thin film, 107-Second TCO thin film, 108-Rear metal gate. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] This invention uses an ellipsometer to measure the film thickness; and uses a UV-Vis-IR spectrometer to measure the transmittance and absorbance of the narrow bandgap TCO material, employing the Tauc relationship (αhν)¹ / ⁿ = B(hν−E). gThe bandgap width data was calculated using the four-probe method or the Hall effect to test the electrical properties of the narrow bandgap TCO thin film. The material showed an increase in carrier concentration and a significant decrease in resistivity after absorbing strong ultraviolet light. XPS measurements revealed an increase in the oxygen vacancy peak content of the narrow bandgap TCO thin film after strong ultraviolet irradiation, indicating an increase in oxygen vacancies after ultraviolet light absorption. This leads to an increase in carrier concentration, a significant decrease in resistivity, and a reduction in work function. Consequently, the contact barrier between the narrow bandgap TCO and the n-type doped silicon-based thin film decreases, improving interface energy level matching, enhancing the transport capability of photogenerated carriers, and contributing to an increase in the fill factor of crystalline silicon heterojunction solar cells.

[0046] Example 1

[0047] This embodiment provides a crystalline silicon heterojunction solar cell resistant to ultraviolet radiation, the structure of which is as follows: Figure 1 As shown, it includes: a crystalline silicon substrate 100; a first intrinsic amorphous silicon thin film 104, an n-type doped silicon thin film 103, a first TCO thin film 102, and a front metal gate 101 stacked on the first surface of the crystalline silicon substrate 100; and a second intrinsic amorphous silicon thin film 105, a p-type doped silicon thin film 106, a second TCO thin film 107, and a rear metal gate 108 stacked on the second surface of the crystalline silicon substrate 100.

[0048] The above-mentioned method for fabricating a crystalline silicon heterojunction solar cell includes the following steps:

[0049] S1. Select a thickness of approximately 90 μm and an area of ​​210 x 105 mm. 2 The p-type single-crystal silicon is used as the crystalline silicon substrate 100 for texturing and cleaning. Specifically, the crystalline silicon substrate 100 is texturized by chemical etching using a chemical wet method (such as KOH, NaOH, etc.), and the crystalline silicon wafer is chemically cleaned using RCA1 and RCA2 solutions.

[0050] S2. Intrinsic amorphous silicon-based thin films (hydrogenated amorphous silicon thin films) are prepared on the surface of a crystalline silicon substrate 100 by vacuum chemical vapor deposition. Specifically, in this embodiment, a first intrinsic amorphous silicon-based thin film 104 is prepared on the first surface of the crystalline silicon substrate 100 by plasma-enhanced chemical vapor deposition (PECVD), and a second intrinsic amorphous silicon-based thin film 105 is prepared on the second surface. The thickness of the films is 5 nm.

[0051] S3. An n-type doped silicon-based thin film 103 and a p-type doped silicon-based thin film 106 are deposited on the surface of the intrinsic amorphous silicon-based thin film, respectively. Specifically, an n-type doped nanocrystalline silicon oxide thin film is deposited on the surface of the first intrinsic amorphous silicon-based thin film 104 by plasma-enhanced chemical vapor deposition, and a p-type doped nanocrystalline silicon oxide thin film is deposited on the surface of the second intrinsic amorphous silicon-based thin film 104. The thickness of the films is 10 nm.

[0052] S4. A first TCO film 102 is prepared on an n-type doped nanocrystalline silicon oxide film by methods such as magnetron sputtering or reactive plasma deposition (RPD) to form the first light-receiving surface. In the prior art, the first TCO is usually a wide-bandgap polycrystalline TCO film with high transmittance and high short-wavelength spectral response, which is beneficial to improving the short-circuit current. However, in this invention, the material of the first TCO film 102 is a narrow-bandgap amorphous transparent conductive oxide. In this embodiment, the first TCO film 102 is prepared by reactive plasma deposition at a film preparation temperature of 150 °C. The selected material is zinc-doped indium oxide (IZO, bandgap of 3.7 eV), and the deposition thickness is 80 nm. A control group of existing high-efficiency batteries is set up simultaneously, and a wide-bandgap cerium-doped indium oxide (ICO, bandgap of 3.9 eV) film is selected to form the first light-receiving surface with a thickness of 80 nm.

[0053] A second TCO film 107 is fabricated on the surface of a p-type doped nanocrystalline silicon oxide film using methods such as magnetron sputtering and reactive plasma deposition (RPD) to form a second light-receiving surface. The material of the second TCO film 107 can be any conductive oxide. In this embodiment, the second TCO film 107 is prepared using reactive plasma deposition, and the selected material is cerium-doped indium oxide (ICO), with a deposition thickness of 80 nm.

[0054] S5. A front metal gate 101 and a rear metal gate 108 are fabricated on the first TCO film 102 and the second TCO film 107 respectively by screen printing. The metal gate material is Ag.

[0055] The narrow-bandgap IZO film and the high-transmittance ICO film on the first light-receiving surface in this embodiment were characterized by testing. Specifically, X-ray diffraction was used to analyze the crystal structure, ultraviolet-visible-infrared spectroscopy was used to test the transmittance and absorbance, and Hall effect testing was used to test the carrier concentration and resistivity of the film.

[0056] XRD results before and after strong ultraviolet irradiation are as follows Figure 2 As shown, IZO and ICO films underwent a vacuum of 3.0 x 10⁻⁶. -5 Pa, strong ultraviolet radiation with wavelengths of 200-400 nm, with an irradiation dose as high as 3000 ESH, from Figure 2 It was found that the amorphous structure of the IZO thin film did not change before and after strong ultraviolet irradiation.

[0057] In this embodiment, the transmittance and absorption spectrum of the narrow bandgap amorphous IZO thin film on the first light-receiving surface are as follows: Figure 3As shown, compared to ICO thin films, narrow-bandgap amorphous IZO thin films have lower transmittance in the 250-400 nm wavelength range but stronger absorption of strong ultraviolet light. In the 400-1200 nm wavelength range, their transmittance is almost identical to that of ICO. When applied to crystalline silicon heterojunction solar cells, the first TCO thin film on the light-receiving surface absorbs ultraviolet light from the incident light. Photons in the 400-1200 nm wavelength range enter the solar cell's internal electrical energy. Photons in the 250-400 nm wavelength range are absorbed by the IZO thin film on the light-receiving surface, increasing the carrier concentration and reducing the resistivity and work function of the IZO thin film. This effectively improves the fill factor of the solar cell, thereby enhancing its resistance to ultraviolet radiation.

[0058] This invention utilizes metal doping and oxygen partial pressure techniques to adjust the optical bandgap, light transmission properties, and electrical properties of TCO thin films, such as... Figure 4 As shown, different transmittances can be obtained during the growth of IZO thin films by adjusting the oxygen flow rate, i.e., the oxygen partial pressure. The electrical properties of IZO thin films with different oxygen partial pressures also differ. The changes in carrier concentration and resistivity of IZO thin films with different oxygen partial pressures can be obtained through Hall effect testing, such as... Figure 5 As shown. Through process optimization, device-grade narrow-bandgap amorphous TCO materials can be obtained. The self-absorption of ultraviolet light by the narrow-bandgap TCO material can prevent ultraviolet light from entering the passivation layer of a crystalline silicon heterojunction solar cell. After absorbing high-energy ultraviolet photons, the TCO material can break the weak chemical bonds between doped metal ions and oxygen, thereby generating more oxygen vacancies, i.e., more charge carriers. This significantly reduces the resistivity and work function of the narrow-bandgap TCO film, helping to improve carrier transport and the fill factor of the solar cell. Specifically, when sunlight reaches the first TCO film surface of the solar cell, visible and near-infrared light are incident inside the solar cell. Strong ultraviolet light is absorbed by the amorphous IZO film. High-energy ultraviolet photons easily break the weak bonds between Zn and O, thereby generating more oxygen vacancies and charge carriers, and significantly reducing the resistivity and work function of the IZO film, such as... Figure 6 and Figure 7 As shown. The reduced resistivity of IZO materials helps lower the series resistance of solar cells, and the reduced work function of IZO helps improve the interface characteristics between IZO and n-type nanocrystalline silicon oxide films, which is beneficial for carrier transport. These properties all contribute to improving the fill factor of solar cells. Some weak ultraviolet photons can enter the passivation layer of solar cells, weakening the voltage and current of the solar cells, but the enhanced fill factor helps maintain the high conversion efficiency of crystalline silicon heterojunction solar cells, such as... Figure 9 As shown in the figure. However, for wide-bandgap ICO thin films, the carrier concentration and resistivity do not change significantly before and after ultraviolet irradiation.

[0059] like Figure 8As shown, compared with the wide-bandgap, high-transmittance ICO thin film, the quantum efficiency curves of the narrow-bandgap IZO thin film crystalline silicon heterojunction solar cell in this embodiment are basically the same in the wavelength range of 400-1200 nm. Although the short-wavelength quantum efficiency of the solar cell is weakened in the short-wavelength range of 300-400 nm, the self-absorption of strong ultraviolet light by the IZO thin film reduces its own resistivity and work function and increases the carrier concentration, thus enhancing the cell's resistance to ultraviolet radiation (e.g., ...). Figure 9 (As shown).

[0060] like Figure 9 As shown, the narrow-bandgap IZO crystalline silicon heterojunction solar cell and the wide-bandgap ICO crystalline silicon heterojunction solar cell in this embodiment operate at a vacuum level of 3.0 x 10⁻⁶. -5 Irradiation was performed under ultraviolet light with wavelengths of 200-400 nm, with an irradiation dose up to 3000 ESH. The results showed that heterojunction solar cells using amorphous narrow-bandgap IZO thin films exhibited significantly higher efficiency retention than those using crystalline wide-bandgap ICO thin films due to changes in their electrical properties induced by the absorption of strong ultraviolet photon energy. In other words, heterojunction solar cells using amorphous narrow-bandgap IZO thin films possess strong resistance to ultraviolet radiation.

[0061] In summary, this invention solves the problem of rapid performance degradation of conventional crystalline silicon heterojunction solar cells after ultraviolet irradiation. It combines the anti-ultraviolet degradation characteristics of terrestrial crystalline silicon heterojunction solar cells with the anti-vacuum ultraviolet degradation characteristics of space-based crystalline silicon heterojunction solar cells. The TCO thin film of this invention exhibits a sharp increase in carrier concentration, a rapid decrease in resistivity, and a decrease in work function under ultraviolet irradiation. This, combined with its neighboring doped silicon-based thin film, helps to enhance the fill factor of the solar cell, thereby improving the ultraviolet irradiation stability of the crystalline silicon heterojunction solar cell.

Claims

1. A crystalline silicon heterojunction solar cell resistant to ultraviolet radiation, characterized in that, The crystalline silicon heterojunction solar cell includes: a crystalline silicon substrate; a first intrinsic amorphous silicon thin film, an n-type doped silicon thin film, a first TCO thin film, and a front metal gate stacked on a first surface of the crystalline silicon substrate; a second intrinsic amorphous silicon thin film, a p-type doped silicon thin film, a second TCO thin film, and a rear metal gate stacked on a second surface of the crystalline silicon substrate; the first surface and the second surface are located on opposite sides of the crystalline silicon substrate.

2. The ultraviolet-irradiation-resistant crystalline silicon heterojunction solar cell according to claim 1, characterized in that, The crystalline silicon substrate is a monocrystalline silicon wafer or a polycrystalline silicon wafer, with a conductivity type of p-type, n-type or intrinsic type, and a thickness of 10-100 µm.

3. The ultraviolet-irradiation-resistant crystalline silicon heterojunction solar cell according to claim 1, characterized in that, The first and second intrinsic amorphous silicon-based thin films are hydrogenated amorphous silicon thin films or hydrogenated amorphous silicon-oxygen thin films, with a film thickness of 1-50 nm.

4. The ultraviolet-irradiation-resistant crystalline silicon heterojunction solar cell according to claim 1, characterized in that, The n-type and p-type doped silicon-based thin films are amorphous, microcrystalline, or amorphous / microcrystalline mixed structures; wherein the silicon-based thin films include silicon thin films or silicon-oxygen thin films, and the film thickness is 1-100 nm.

5. The ultraviolet-irradiation-resistant crystalline silicon heterojunction solar cell according to claim 1, characterized in that, The first TCO film is a transparent conductive oxide material containing indium or zinc, including one or more of zinc-doped indium oxide, tungsten-doped indium oxide, aluminum-doped zinc oxide, and indium oxide or zinc oxide co-doped with various cations, with a band gap between 3.0 and 3.8 eV; the second TCO film material is a narrow band gap material or a wide band gap film material that is the same as or different from the first TCO film; the first and second TCO films are single-layer films or multi-layer composite film structures with a thickness of 10-200 nm; the first TCO film is an amorphous structure and remains an amorphous structure after ultraviolet irradiation; the second TCO film is an amorphous or polycrystalline structure and remains an amorphous or polycrystalline structure after ultraviolet irradiation.

6. The ultraviolet-irradiation-resistant crystalline silicon heterojunction solar cell according to claim 1, characterized in that, The metal gate material includes one or more of Ag, Cu, Ag-encapsulated Cu, Au, and Al.

7. A method for fabricating a crystalline silicon heterojunction solar cell resistant to ultraviolet radiation, comprising the following steps: S1. A crystalline silicon substrate is cleaned and texturized to obtain a surface structure with light-trapping properties; S2. A first intrinsic amorphous silicon-based thin film and a second intrinsic amorphous silicon-based thin film are deposited on opposite sides of a texturized crystalline silicon substrate, respectively. S3. Deposit an n-type doped silicon-based thin film on the first intrinsic amorphous silicon-based thin film, and deposit a p-type doped silicon-based thin film on the second intrinsic amorphous silicon-based thin film; S4. A first TCO film is deposited on an n-type doped silicon-based thin film to form a first light-receiving surface, and a second TCO film is deposited on a p-type doped silicon-based thin film to form a second light-receiving surface; S5. A front metal gate and a back metal gate are fabricated on the first TCO thin film and the second TCO thin film, respectively, thereby completing the fabrication of a crystalline silicon heterojunction solar cell.

8. The preparation method according to claim 7, characterized in that, Step S1 specifically involves: preparing a light-trapping textured surface structure on the surface of a crystalline silicon substrate using a chemical wet process, followed by chemical wet cleaning; the average reflectivity of the crystalline silicon substrate after cleaning and texturing is between 1% and 30%.

9. The preparation method according to claim 7, characterized in that, The first and second intrinsic amorphous silicon-based thin films in step S2 and the n-type and p-type doped silicon-based thin films in step S3 are prepared by plasma-enhanced chemical vapor deposition or hot-wire chemical vapor deposition.

10. The preparation method according to claim 7, characterized in that, Step S4: The preparation methods of the first and second TCO thin films include at least one of magnetron sputtering, electron beam evaporation, physical vapor deposition, thermal evaporation, and reactive plasma deposition, with the thin film deposition temperature not exceeding 250 °C; Step S5: The preparation methods of the front and rear metal gates include any one of screen printing, electroplating, and inkjet printing.

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