A front-side film layer for solar cells with UV-resistant degradation effect and its preparation method

Abstract

This application relates to the field of solar cell technology, specifically disclosing a front-side film layer for solar cells with anti-UV degradation effect and its preparation method. The front-side film layer includes an anti-reflection layer and a stacked alumina layer, with the anti-reflection layer located outside the stacked alumina layer; the anti-reflection layer includes a low-bandgap, high-refractive-index silicon nitride layer; the stacked alumina layer (2) includes a low-hydrogen-content alumina layer, which is deposited using an ALD process, wherein the low-hydrogen-content alumina layer is obtained by reducing the water flux and / or water pulse time during the deposition process. The low-bandgap, high-refractive-index silicon nitride layer of this application captures and absorbs the energy of UV photons, reducing UV damage to the silicon substrate interface, while the low-hydrogen-content alumina layer blocks the diffusion of active hydrogen to the silicon substrate interface; through the synergistic effect of the film layers, the anti-UV degradation performance is improved while ensuring photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a front-side film layer for solar cells with anti-UV degradation effect and its preparation method. Background Technology

[0002] Solar energy, as a clean and renewable energy source, is being used more and more widely in the energy sector. Solar cells are the core components that convert solar energy into electricity, and their efficiency and stability are important indicators for measuring their performance. However, ultraviolet (UV) degradation can adversely affect the performance of solar cells.

[0003] UV degradation prevents some high-energy light from being utilized by photovoltaic cells, thus reducing their power generation efficiency. This is the main problem causing the efficiency decline of photovoltaic cells under long-term exposure to ultraviolet radiation, and its mechanism includes:

[0004] 1. Si passivation damage: UV photons (280-400nm) inject electrons into the SiO2 interface, which leads to an increase in recombination centers at the Si / SiO2 interface, changes the fixed charge density and increases the density of interface defects near the Si surface, thereby destroying the surface passivation.

[0005] 2. Hot carrier destruction: High-energy photons can generate hot electrons, which have high mobility and energy, enough to exceed the interface barrier and be injected into the interface, thereby destroying the passivation layer and increasing the interface state density.

[0006] 3. Chemical passivation loss: UV irradiation disrupts the Si-H bonds at the interface, and the secondary distribution of hydrogen leads to an excess of H atoms, which promotes carrier recombination.

[0007] To address the issue of UV degradation in solar cells, existing technologies typically employ single measures such as increasing the thickness of the alumina film, raising the refractive index of the silicon nitride film, or lowering the refractive index of the silicon nitride film. However, these measures significantly reduce the passivation performance of the solar cells (reduced Uoc and Isc), as well as the cell efficiency and provide poor UV resistance. Furthermore, existing technologies suffer from the following drawbacks: the film has a single function and cannot simultaneously address both UV absorption and hydrogen management; UV degradation and cell efficiency cannot be balanced, hindering mass production.

[0008] Therefore, there is an urgent need for a technical solution that can effectively improve the UV degradation resistance of solar cells without reducing battery efficiency. Summary of the Invention

[0009] This application addresses the aforementioned problems by providing a front-side film layer for solar cells with UV-resistant degradation and its preparation method. This solves the problem in the prior art where UV degradation and cell efficiency cannot be balanced, thereby improving the cell's ability to resist UV degradation while minimizing the reduction in cell efficiency.

[0010] This application is achieved through the following technical solution:

[0011] This application provides a front-side film layer for a solar cell with UV-resistant degradation effect, comprising an antireflection layer and a stacked alumina layer, wherein the antireflection layer is located outside the stacked alumina layer; the antireflection layer comprises a low-bandgap, high-refractive-index silicon nitride layer, wherein the bandgap of the low-bandgap, high-refractive-index silicon nitride layer is 3eV~3.6eV, the refractive index is 2.1~2.8, and the thickness accounts for 5%~30% of the thickness of the antireflection layer; the stacked alumina layer (2) comprises a low-hydrogen-content alumina layer, wherein the stacked alumina layer is deposited using an ALD process, wherein the low-hydrogen-content alumina layer is obtained by reducing the water flux and / or water pulse time during the deposition process. The bandgap of the low-bandgap, high-refractive-index silicon nitride layer can be 3eV, 3.1eV, 3.3eV, 3.4eV, 3.5eV, 3.6eV, etc., and the refractive index can be 2.1, 2.3, 2.4, 2.5, 2.7, 2.8, etc.

[0012] This application employs a low-bandgap, high-refractive-index silicon nitride layer matched with a low-hydrogen-content alumina layer. This reduces the interfacial hydrogen concentration to suppress hot carrier destruction and reduces light reflection loss through pre-photon absorption and refractive index matching, thereby improving UV degradation resistance while maintaining photoelectric conversion efficiency. Specifically, the low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3eV~3.6eV and a refractive index of 2.1~2.8 (compared to 1.8~2.0 for conventional silicon nitride) can improve the absorption of UV light in the 280nm~400nm wavelength range and reduce UV light damage to the silicon substrate passivation. However, this also means that the silicon nitride layer has a high hydrogen content. The low-hydrogen-content alumina layer can capture the high hydrogen content in the silicon nitride layer, preventing its bonding with the silicon substrate and reducing Si-H bond breakage. Thus, the UV degradation rate is reduced while maintaining the initial cell efficiency.

[0013] Furthermore, the reduction of water flux includes: canceling the deposition process of the first layer of water in the deposition process of the stacked alumina layer (2), and / or reducing the water flux of any one layer of the deposition process in the stacked alumina layer (2), and / or reducing the water flux of at least one layer of the deposition process in the stacked alumina layer (2).

[0014] Further, the film layer in the stacked alumina layer (2) that reduces water flux is the low-hydrogen-content alumina layer; during the deposition process, the aluminum source flux of the low-hydrogen-content alumina layer is 16 sccm~26 sccm, and the water flux is 6 sccm~25 sccm, with a reduction in water flux of 1 sccm~10 sccm relative to the aluminum source flux. The aluminum source flux during the deposition process can be 16 sccm, 17 sccm, 18 sccm, 20 sccm, 22 sccm, 23 sccm, 26 sccm, etc.; the water flux during the deposition process can be 6 sccm, 9 sccm, 11 sccm, 12 sccm, 14 sccm, 17 sccm, 22 sccm, 23 sccm, 25 sccm, etc.

[0015] Furthermore, the reduction of water pulse time includes: reducing the water pulse time of any one of the deposition processes in the stacked alumina layers (2), and / or reducing the water pulse time of at least one deposition process in the stacked alumina layers (2).

[0016] Further, the film layer in the stacked alumina layer (2) that reduces the water pulse time is the low-hydrogen-content alumina layer; during the deposition process, the aluminum source pulse time of the low-hydrogen-content alumina layer is 4s~8s, and the water pulse time is 0.5s~7.5s, with the reduction in water pulse time being 0.5s~4s relative to the aluminum source pulse time. The aluminum source pulse time during the deposition process can be 4s, 5s, 6s, 3s, 6.5s, 7s, 7.5s, 8s, etc.; the water pulse time during the deposition process can be 0.5s, 1s, 2.5s, 3s, 3.5s, 4s, 4.5s, 5s, 5.5s, 6s, 7.5s, etc.

[0017] Preferably, the aluminum source is TMA.

[0018] Furthermore, it also includes a low-hydrogen-content barrier layer located between the stacked alumina layer and the low-bandgap, high-refractive-index silicon nitride layer, wherein the refractive index of the barrier layer is 1.65 to 2.1. The refractive index can be 1.65, 1.7, 1.8, 1.85, 1.95, 2, 2.05, 2.1, etc.

[0019] This application provides a barrier layer that blocks high-energy ultraviolet light from penetrating, while also acting as a hydrogen diffusion barrier to further maintain passivation stability and reduce hydrogen diffusion to the silicon substrate interface.

[0020] Furthermore, the material of the barrier layer is Si. x O y Si x N y and Si x Oy N z Any of the following, with a thickness of 1nm to 10nm. The thickness of the cathode layer can be 1nm, 3nm, 5nm, 7nm, 9nm, 10nm, etc.

[0021] Furthermore, the thickness of the stacked alumina layer is 2nm to 10nm, and it comprises at least one low-hydrogen-content alumina layer. The thickness of the stacked alumina layer can be 2nm, 4nm, 6nm, 8nm, 10nm, etc.; the low-hydrogen-content alumina layer film can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, etc.

[0022] Furthermore, the antireflective layer is made of Si. x O y Si x N y and Si x O y N z One or more of the following; the material of the low-bandgap, high-refractive-index silicon nitride layer is Si. x N y The thickness is 5nm to 30nm. The thickness of the low-bandgap, high-refractive-index silicon nitride layer can be 5nm, 9nm, 10nm, 15nm, 18nm, 20nm, 25nm, 27nm, 30nm, etc.

[0023] Furthermore, the antireflective layer comprises a first silicon nitride layer, a second silicon nitride layer, a third silicon nitride layer, a first silicon oxynitride layer, a second silicon oxynitride layer, and a silicon oxide layer, which are sequentially disposed from the side closest to the stacked alumina layer to the side furthest from the stacked alumina layer.

[0024] Furthermore, the first silicon nitride layer is a silicon nitride layer with a low band gap and a high refractive index, or the second silicon nitride layer is a silicon nitride layer with a low band gap and a high refractive index, or the third silicon nitride layer is a silicon nitride layer with a low band gap and a high refractive index.

[0025] This application also provides a method for preparing the above-mentioned front-side film layer of a solar cell, comprising the following steps:

[0026] S1: An aluminum oxide layer is deposited on the front side of the solar cell using the ALD process, with a deposition temperature of 200℃~350℃.

[0027] S2: An antireflective layer is deposited on the outer surface of the stacked alumina layer by PECVD process. During the deposition process, the ratio of SiH4 to NH3 intake is 24%~60%, and the deposition temperature is 200℃~600℃.

[0028] Furthermore, it also includes a barrier layer deposition step between S1 and S2, wherein the barrier layer is deposited using a PECVD process, and during the deposition process, the ratio of SiH4 to NH3 intake is 5% to 23%, and the deposition temperature is 200℃ to 600℃.

[0029] This application also provides a solar cell comprising the aforementioned front film layer of a solar cell, wherein the solar cell is a TOPCon cell or a BC cell.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) This application effectively reduces the passivation layer damage caused by ultraviolet radiation while maintaining the initial efficiency of the solar cell. Through the synergistic effect of the film layers, it reduces the interfacial hydrogen concentration to suppress the destruction of hot carriers, and reduces light reflection loss through pre-photon absorption and refractive index matching, thereby improving the anti-ultraviolet degradation performance while ensuring the photoelectric conversion efficiency.

[0032] (2) The process of this application is simple, no additional steps such as annealing are required, the process parameters are compatible with existing ALD / PECVD production lines, no new equipment is required, and it is suitable for mass production. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the front film structure of a solar cell with UV degradation resistance provided in Embodiments 1-3 of this application;

[0035] Figure 2 This is a schematic diagram of the front film structure of a solar cell with anti-UV degradation effect provided in Embodiments 4 and 5 of the present invention.

[0036] Explanation of key figure labels:

[0037] 1. Silicon substrate; 2. Stacked aluminum oxide layer; 3. First silicon nitride layer; 4. Second silicon nitride layer; 5. Third silicon nitride layer; 6. First silicon oxynitride layer; 7. Second silicon oxynitride layer; 8. Silicon oxide layer; 9. Barrier layer. Detailed Implementation

[0038] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known materials or methods have not been specifically described in order to avoid obscuring the invention.

[0039] Throughout this specification, references to “an embodiment,” “an example,” or “an example” mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases “an embodiment,” “an example,” “an example,” or “an example” appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0040] Terminology Explanation:

[0041] TOPCon: Tunnel Oxide Passivated Contact;

[0042] BC: Back Contact Battery;

[0043] PECVD: Plasma-enhanced chemical vapor deposition;

[0044] ALD: Atomic Layer Deposition;

[0045] RCA: Cleaning process:

[0046] UVID: Ultraviolet Degradation;

[0047] TMA: Trimethylaluminum;

[0048] In the existing technology, silicon nitride is divided into silicon-rich silicon nitride (high refractive index) and nitrogen-rich silicon nitride (low refractive index). The band gap of the former is generally around 2eV~3eV, while that of nitrogen-rich silicon nitride is above 4eV. The band gap of pure silicon nitride is 4.6eV. The 280nm~400nm wavelength band is the UVID test condition, and the photon energy is 3.1eV~4.43eV (λ=1240 / Eg). The 3.4eV ultraviolet A (UVA) light at around 360nm can break the Si-H bond.

[0049] In conventional ALD (Alternating Current Deposition) processes for depositing multilayer alumina layers, the aluminum source flux and water flux are the same, but the aluminum source pulse time is slightly shorter than the water pulse time. This results in a high content of hydroxyl groups (-OH) and adsorbed water (H2O) within the film. Under UV irradiation, hydrogen atoms easily diffuse to the silicon interface, disrupting the Si-H passivation bonds. For example, in a conventional ALD process for depositing a two-layer multilayer alumina layer: the first layer uses only water at a flow rate of 24 sccm, a pulse time of 6.5 s, and is cycled 5 times; the second layer uses trimethylaluminum (TMA) as the aluminum source, and the second layer uses both TMA and water, with the TMA flow rate at 24 sccm and a pulse time of 6 s, and the H2O flow rate at 24 sccm and a pulse time of 6.5 s, for a total of 33 cycles.

[0050] In a first aspect, this application provides a front-side film layer for a solar cell with resistance to UV degradation, comprising an antireflection layer and a stacked alumina layer 2, wherein the antireflection layer is located outside the stacked alumina layer 2; the antireflection layer comprises a low-bandgap, high-refractive-index silicon nitride layer, wherein the bandgap of the low-bandgap, high-refractive-index silicon nitride layer is 3eV~3.6eV, the refractive index is 2.1~2.8, and the thickness accounts for 5%~30% of the thickness of the antireflection layer; the stacked alumina layer 2 comprises a low-hydrogen-content alumina layer, wherein the stacked alumina layer 2 is deposited using an ALD process, wherein the low-hydrogen-content alumina layer is obtained by reducing the water flux and / or water pulse time during the deposition process.

[0051] In this application, the "hydrogen" in alumina mainly exists in the form of hydroxyl groups (-OH), with some remaining as physically adsorbed H2O molecules. During ALD deposition, the hydrolysis reaction of the aluminum source precursor (such as TMA) introduces a large number of -OH bonds; these -OH bonds act as carriers for hydrogen diffusion and decompose during high-temperature sintering to generate active hydrogen atoms (H2O). 0 Excessive hydrogen content can lead to a burst of hydrogen release, which diffuses to the silicon interface and destroys the Si-H passivation bonds. Furthermore, H2O molecules that are not fully removed during deposition are trapped in the film pores and released as H2O during subsequent processes (such as sintering). + / OH - Ions participate in interfacial reactions.

[0052] This application utilizes a low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3eV~3.6eV and a refractive index of 2.1~2.8 (compared to 1.8~2.0 for conventional silicon nitride) to improve the absorption of UV light in the 280nm~400nm band and reduce UV light damage to the silicon substrate passivation. However, this also means that the silicon nitride layer has a high hydrogen content. Therefore, by adding a low-hydrogen-content alumina layer 2, the hydrogen content at the interface between the silicon substrate and the low-hydrogen-content alumina layer 2 can be reduced. On the other hand, after sintering, hydrogen in the silicon nitride layer can be captured, preventing its bonding with the silicon substrate and reducing Si-H bond breakage. Thus, the UV decay rate is reduced while maintaining the efficiency of the initial solar cell.

[0053] In one specific embodiment, the reduction of water flux includes: canceling the deposition process of the first layer of water in the deposition process of the stacked alumina layer 2, and / or reducing the water flux of any layer deposition process in the stacked alumina layer 2, and / or reducing the water flux of at least one layer deposition process in the stacked alumina layer 2.

[0054] In one specific embodiment, the film layer that reduces water flux in the stacked alumina layer 2 is an alumina layer with low hydrogen content; during the deposition process, the aluminum source flux of the low hydrogen content alumina layer is 16 sccm to 26 sccm, and the water flux is 6 sccm to 25 sccm; relative to the aluminum source flux, the reduction in water flux is 1 sccm to 10 sccm.

[0055] In one specific embodiment, the water pulse time is reduced by: reducing the water pulse time of any one of the deposition processes in the stacked alumina layers 2, and / or reducing the water pulse time of at least one deposition process in the stacked alumina layers 2.

[0056] In one specific embodiment, the film layer in the stacked alumina layer 2 that reduces the water pulse time is an alumina layer with low hydrogen content; during the deposition process of the alumina layer with low hydrogen content, the aluminum source pulse time is 4s~8s and the water pulse time is 0.5s~7.5s; the reduction in water pulse time relative to the aluminum source pulse time is 0.5s~4s.

[0057] In one specific embodiment, a low-hydrogen-content barrier layer 9 is also included. The barrier layer 9 is located between the stacked alumina layer 2 and the low-bandgap, high-refractive-index silicon nitride layer. The refractive index of the barrier layer 9 is 1.65 to 2.1.

[0058] This application provides a barrier layer 9 with a refractive index between 1.65 and 2.1 to block the penetration of high-energy ultraviolet rays, while also serving as a hydrogen diffusion barrier to maintain the passivation stability of the solar cell and further reduce the diffusion of hydrogen to the silicon substrate interface.

[0059] In one specific embodiment, the material of the barrier layer 9 is Si. x O y Si x N y and Si x O y N z Any of the following, with a thickness of 1nm to 10nm.

[0060] In one specific embodiment, the thickness of the stacked alumina layer 2 is 2nm to 10nm, and it includes at least one alumina layer with low hydrogen content.

[0061] In one specific embodiment, the antireflection layer is made of Si. x O y Six N y and Si x O y N z One or more of the following; the material of the low-bandgap, high-refractive-index silicon nitride layer is Si. x N y The thickness is 5nm~30nm.

[0062] In one specific embodiment, the antireflection layer comprises six film layers, including a first silicon nitride layer 3, a second silicon nitride layer 4, a third silicon nitride layer 5, a first silicon oxynitride layer 6, a second silicon oxynitride layer 7, and a silicon oxide layer 8, which are sequentially disposed from the side closest to the stacked alumina layer 2 to the side furthest from the stacked alumina layer 2.

[0063] In one specific embodiment, the first silicon nitride layer 3 is a silicon nitride layer with a low band gap and a high refractive index, or the second silicon nitride layer 4 is a silicon nitride layer with a low band gap and a high refractive index, or the third silicon nitride layer 5 is a silicon nitride layer with a low band gap and a high refractive index.

[0064] Secondly, this application also provides a method for preparing the above-mentioned front-side film layer of a solar cell, comprising the following steps:

[0065] S1: A multilayer aluminum oxide layer 2 is deposited on the front side of the solar cell using the ALD process, with a deposition temperature of 200℃~350℃;

[0066] S2: An antireflective layer is deposited on the outer surface of the stacked alumina layer 2 by PECVD process. During the deposition process, the ratio of SiH4 to NH3 intake is 24%~60%, and the deposition temperature is 200℃~600℃.

[0067] This application reduces the diffusible hydrogen content by controlling the process to decrease hydroxyl groups (-OH) and adsorbed water (H2O) during the deposition of the stacked alumina layer 2. First, in step S1, a stacked alumina layer 2 with low hydrogen content is achieved through ALD process parameter optimization: this is done by reducing the water flux and / or water pulse time during the deposition process. Specifically, the reduction in water flux includes canceling the deposition of the first water layer in the stacked alumina layer 2 deposition process to avoid initial interface hydrogen enrichment, and / or reducing the water flux of any one layer of the stacked alumina layer 2 deposition process, and / or reducing the water flux of at least one layer of the stacked alumina layer 2 deposition process. During the deposition process, the layer in the stacked alumina layer 2 with reduced water flux is the low-hydrogen-content alumina layer, and the aluminum source flux of the low-hydrogen-content alumina layer is... The water pulse time is 16 sccm to 26 sccm, and the water flux is 6 sccm to 25 sccm. The reduction in water flux relative to the aluminum source flux is 1 sccm to 10 sccm. The reduction in water pulse time includes reducing the water pulse time of any one of the deposition processes in the stacked alumina layers 2, and / or reducing the water pulse time of at least one deposition process in the stacked alumina layers 2. During deposition, the film layer in the stacked alumina layers 2 that reduces water pulse time is a low-hydrogen-content alumina layer. The aluminum source pulse time of the low-hydrogen-content alumina layer is 4 s to 8 s, and the water pulse time is 0.5 s to 7.5 s. The reduction in water pulse time relative to the aluminum source pulse time is 0.5 s to 4 s. Therefore, by precisely controlling the hydroxyl content during alumina growth, the hydrogen atom concentration within the film layer is reduced, thereby reducing passivation failure caused by secondary hydrogen distribution under UV irradiation. Secondly, in step S2, by controlling the ratio of SiH4 to NH3 intake during silicon oxide deposition to 24%~60%, a low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3eV~3.6eV and a refractive index of 2.1-2.8 is prepared. This low-bandgap characteristic can selectively absorb high-energy ultraviolet photons and convert them into thermal energy, while the high refractive index characteristic forms a better refractive index gradient with the silicon substrate, reducing surface reflection while achieving pre-absorption of ultraviolet photons and avoiding damage to the underlying passivation structure. Thus, the performance of maintaining the initial efficiency of the solar cell while reducing the UV decay rate is achieved.

[0068] In one specific embodiment, the method further includes a barrier layer 9 deposition step between S1 and S2. The barrier layer 9 is deposited using a PECVD process. During the deposition process, the ratio of SiH4 to NH3 intake is 5% to 23%, and the deposition temperature is 200℃ to 600℃.

[0069] This application further deposits a barrier layer 9 with a low hydrogen content and a refractive index of 1.65-2.1, which can effectively block high-energy ultraviolet photons from penetrating into the silicon substrate without excessively increasing light reflection loss. At the same time, it acts as a hydrogen diffusion barrier to maintain the stability of the passivation layer of the cell, thereby reducing the diffusion of hydrogen to the silicon substrate interface in one step.

[0070] Thirdly, this application also provides a solar cell comprising the aforementioned front-side film layer of a solar cell, wherein the solar cell is a TOPCon cell or a BC cell.

[0071] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0072] Example 1

[0073] like Figure 1 As shown, a front-side film layer for a solar cell with UV-resistant degradation effect includes an anti-reflection layer and a stacked alumina layer 2. The stacked alumina layer (2) contains an alumina layer with low hydrogen content, and the anti-reflection layer is located outside the stacked alumina layer 2. The anti-reflection layer includes a first silicon nitride layer 3, a second silicon nitride layer 4, a third silicon nitride layer 5, a first silicon oxynitride layer 6, a second silicon oxynitride layer 7, and a silicon oxide layer 8, which are sequentially arranged from the side closest to the stacked alumina layer 2 to the side away from the stacked alumina layer 2. Among them, the first silicon nitride layer 3 is a silicon nitride layer with low band gap and high refractive index, with a band gap of 3.3 eV and a refractive index of 2.7.

[0074] This embodiment provides a method for preparing a front-side film layer of a solar cell with resistance to UV degradation. It provides a crystalline silicon solar cell with a complete pn junction and currently in normal operation on a production line. The front-side film layer structure needs to be prepared, and the steps are as follows:

[0075] After RCA, the solar cell is deposited with a multilayer alumina film 2 using the ALD process: the deposition temperature is 200℃, the first layer is only circulated with H2O at a flow rate of 20 sccm, a pulse time of 4s, a purge time of 10s, and 5 cycles; the second layer is circulated with trimethylaluminum TMA and H2O, where the flow rate of trimethylaluminum TMA is 20 sccm, the pulse time is 6s, and the purge time is 10s, the flow rate of H2O is 15 sccm, the pulse time is 6s, and the purge time is 10s, and the trimethylaluminum TMA and H2O are circulated 33 times. The thickness of the low-hydrogen content alumina layer 2 is 6nm.

[0076] Antireflection layers (7 layers) were deposited using PECVD: The first layer, a low-bandgap, high-refractive-index silicon nitride (layer 3), was deposited with a SiH4 inlet flow rate of 3000 sccm, an NH3 inlet flow rate of 7000 sccm, an Eg=3.3 eV, n=2.7, and a thickness of 11 nm; the second layer, a silicon nitride (layer 4), had a SiH4 inlet flow rate of 1700 sccm, an NH3 inlet flow rate of 10000 sccm, and a thickness of 12 nm; the third layer, a silicon nitride (layer 5), had a SiH4 inlet flow rate of 1200 sccm, and an NH3 inlet flow rate of 12000 sccm. The first silicon oxynitride layer 6 has a SiH4 inlet flow rate of 1000 sccm, an NH3 inlet flow rate of 5000 sccm, and an N2O inlet flow rate of 7000 sccm, with a thickness of 10 nm. The second silicon oxynitride layer 7 has a SiH4 inlet flow rate of 1000 sccm, an NH3 inlet flow rate of 4000 sccm, and an N2O inlet flow rate of 9000 sccm, with a thickness of 11 nm. The third silicon oxide layer 8 has a SiH4 inlet flow rate of 800 sccm, an N2O inlet flow rate of 11000 sccm, and a thickness of 7 nm. After the antireflection layer deposition process is completed, the following is obtained: Figure 1 The front film structure of the battery is shown.

[0077] Example 2

[0078] like Figure 1 As shown, a front-side film layer for a solar cell with UV-resistant degradation effect includes an anti-reflection layer and a low-hydrogen-content alumina layer 2. The stacked alumina layer (2) contains a low-hydrogen-content alumina layer, and the anti-reflection layer is located outside the stacked alumina layer 2. The anti-reflection layer includes a first silicon nitride layer 3, a second silicon nitride layer 4, a third silicon nitride layer 5, a first silicon oxynitride layer 6, a second silicon oxynitride layer 7, and a silicon oxide layer 8, which are sequentially arranged from the side closest to the stacked alumina layer 2 to the side away from the stacked alumina layer 2. Among them, the second silicon nitride layer 4 is a low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3.3 eV and a refractive index of 2.7.

[0079] This embodiment provides a method for preparing a front-side film layer of a solar cell with resistance to UV degradation. It provides a crystalline silicon solar cell with a complete pn junction and currently in normal operation on a production line. The front-side film layer structure needs to be prepared, and the steps are as follows:

[0080] After RCA, the solar cell is deposited with a tandem alumina layer 2 using the ALD process: the deposition temperature is 250℃. The first layer is circulated with TMA and H2O, with a TMA flow rate of 25 sccm, a pulse time of 6s, and a purge time of 10s, and an H2O flow rate of 25 sccm, a pulse time of 6s, and a purge time of 10s. The TMA and H2O are circulated 20 times. The second layer is circulated with TMA and H2O, with a TMA flow rate of 25 sccm, a pulse time of 6s, and a purge time of 10s, and an H2O flow rate of 20 sccm, a pulse time of 6s, and a purge time of 10s. The TMA and H2O are circulated 13 times, and the thickness is 6nm.

[0081] Antireflection layers (7 layers) were deposited using PECVD: First silicon nitride layer: SiH4 inlet rate 2300 sccm, NH3 inlet rate 9800 sccm, thickness 15 nm, Eg=3.6eV, n=2.0; Second silicon nitride layer (low bandgap, high refractive index): SiH4 inlet rate 3000 sccm, NH3 inlet rate 7000 sccm, Eg=3.3eV, n=2.7, thickness 11 nm; Third silicon nitride layer 5: SiH4 inlet rate 1200 sccm, NH3 inlet rate 12000 sccm, thickness 20 nm; First Si x O y N z Layer 6: SiH4 intake is 1000 sccm, NH3 intake is 5000 sccm, N2O intake is 7000 sccm, and thickness is 10 nm; the second Si x O y N z Layer 7: SiH4 intake is 1000 sccm, NH3 intake is 4000 sccm, N2O intake is 9000 sccm, and thickness is 11 nm; Si x O y Layer 8: SiH4 inlet flow rate is 800 sccm, N2O inlet flow rate is 11000 sccm, and thickness is 7 nm. After the antireflection layer deposition process, the following is obtained: Figure 1 The front film structure of the battery is shown.

[0082] Example 3

[0083] like Figure 1As shown, a front-side film layer for a solar cell with UV-resistant degradation effect includes an anti-reflection layer and a stacked alumina layer 2 with low hydrogen content. The stacked alumina layer (2) contains an alumina layer with low hydrogen content, and the anti-reflection layer is located outside the stacked alumina layer 2. The anti-reflection layer includes a first silicon nitride layer 3, a second silicon nitride layer 4, a third silicon nitride layer 5, a first silicon oxynitride layer 6, a second silicon oxynitride layer 7, and a silicon oxide layer 8, which are sequentially arranged from the side closest to the stacked alumina layer 2 to the side away from the stacked alumina layer 2. Among them, the third silicon nitride layer 5 is a silicon nitride layer with low band gap and high refractive index, with a band gap of 3.3 eV and a refractive index of 2.7.

[0084] This embodiment provides a method for preparing a front-side film layer of a solar cell with resistance to UV degradation. It provides a crystalline silicon solar cell with a complete pn junction and currently in normal operation on a production line. The front-side film layer structure needs to be prepared, and the steps are as follows:

[0085] After RCA, the solar cells are deposited with a tandem alumina layer 2 using the ALD process: the deposition temperature is 350℃. The first layer is only circulated with H2O at a flow rate of 23 sccm, a pulse time of 6s, a purge time of 10s, and 5 cycles. The second layer is circulated with TMA and H2O, where the TMA flow rate is 25 sccm, the pulse time is 6s, and the purge time is 10s, and the H2O flow rate is 20 sccm, the pulse time is 4s, and the purge time is 10s, and the TMA and H2O cycle is circulated 25 times. The third layer is circulated with TMA and H2O, where the TMA flow rate is 25 sccm, the pulse time is 6s, and the purge time is 10s, and the H2O flow rate is 16 sccm, the pulse time is 3s, and the purge time is 8s, and the TMA and H2O cycle is circulated 15 times.

[0086] Antireflection layers (7 layers) were deposited using PECVD: First silicon nitride layer: SiH4 inlet flow rate 2300 sccm, NH3 inlet flow rate 9800 sccm, thickness 15nm, Eg=3.6eV, n=2.0; Second silicon nitride layer (low bandgap, high refractive index): SiH4 inlet flow rate 3000 sccm, NH3 inlet flow rate 7000 sccm, Eg=3.3eV, n=2.7, thickness 11nm; Third silicon nitride layer 5: SiH4 inlet flow rate 1200 sccm, NH3 inlet flow rate 12000 sccm, thickness 20nm; First silicon oxynitride layer 6: SiH4... The first layer has an intake air volume of 1000 sccm, an NH3 intake air volume of 5000 sccm, and an N2O intake air volume of 7000 sccm, with a thickness of 10 nm; the second silicon oxynitride layer 7 has an intake air volume of 1000 sccm for SiH4, 4000 sccm for NH3, and 9000 sccm for N2O, with a thickness of 11 nm; the third layer 8 has an intake air volume of 800 sccm for SiH4 and 11000 sccm for N2O, with a thickness of 7 nm. After the antireflection layer deposition process, the following is obtained: Figure 1 The front film structure of the battery is shown.

[0087] Example 4

[0088] like Figure 2 As shown, a front-side film layer for a solar cell with UV degradation resistance includes a stacked alumina layer 2, an antireflection layer, and a low-hydrogen content barrier layer 9. The stacked alumina layer (2) contains a low-hydrogen content alumina layer, and the low-hydrogen content barrier layer 9 is located outside the stacked alumina layer 2, and the antireflection layer is located outside the low-hydrogen content barrier layer 9. The antireflection layer includes a first silicon nitride layer 3, a second silicon nitride layer 4, a third silicon nitride layer 5, a first silicon oxynitride layer 6, a second silicon oxynitride layer 7, and a silicon oxide layer 8, which are sequentially arranged from the side closest to the stacked alumina layer 2 to the side away from the stacked alumina layer 2. The first silicon nitride layer 3 is a low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3.35 eV and a refractive index of 2.62.

[0089] This embodiment provides a method for preparing a front-side film layer of a solar cell with resistance to UV degradation. It provides a crystalline silicon solar cell with a complete pn junction and currently in normal operation on a production line. The front-side film layer structure needs to be prepared, and the steps are as follows:

[0090] After RCA, the solar cell is deposited with a tandem alumina layer 2 using the ALD process: the deposition temperature is 250℃. The first layer is circulated with TMA and H2O, with a TMA flow rate of 25 sccm, a pulse time of 6s, and a purge time of 10s, and an H2O flow rate of 25 sccm, a pulse time of 3s, and a purge time of 10s. The TMA and H2O are circulated 20 times. The second layer is circulated with TMA and H2O, with a TMA flow rate of 25 sccm, a pulse time of 6s, and a purge time of 10s, and an H2O flow rate of 20 sccm, a pulse time of 6s, and a purge time of 10s. The TMA and H2O are circulated 13 times, and the thickness is 6nm.

[0091] A barrier layer 9 is first deposited on the surface of the low-hydrogen-content stacked alumina layer 2 by PECVD process. The deposition temperature is 250℃, the SiH4 inlet is 1400sccm, the NH3 inlet is 28000sccm, Eg=3.8eV, n=2.08, and the thickness is 3.5nm.

[0092] Then, an antireflection layer (7 layers) is deposited using PECVD: the first low-bandgap, high-refractive-index silicon nitride layer 3: SiH4 inlet rate 2800 sccm, NH3 inlet rate 7000 sccm, Eg=3.35eV, n=2.62, thickness 11nm; the second silicon nitride layer 4: SiH4 inlet rate 1700 sccm, NH3 inlet rate 10000 sccm, thickness 12nm; the third silicon nitride layer 5: SiH4 inlet rate 1200 sccm, NH3 inlet rate 12000 sccm. The antireflection layer has a thickness of 20 nm and a diameter of 1 cm. The first silicon oxynitride layer 6 has a SiH4 inlet flow rate of 1000 sccm, an NH3 inlet flow rate of 5000 sccm, and an N2O inlet flow rate of 7000 sccm, with a thickness of 10 nm. The second silicon oxynitride layer 7 has a SiH4 inlet flow rate of 1000 sccm, an NH3 inlet flow rate of 4000 sccm, and an N2O inlet flow rate of 9000 sccm, with a thickness of 11 nm. The silicon oxide layer 8 has a SiH4 inlet flow rate of 800 sccm, an N2O inlet flow rate of 11000 sccm, and a thickness of 7 nm. After the antireflection layer deposition process is completed, the following is obtained: Figure 2 The front film structure of the battery is shown.

[0093] Example 5

[0094] like Figure 2As shown, a front-side film layer for a solar cell with UV degradation resistance includes a stacked alumina layer 2, an antireflection layer, and a low-hydrogen content barrier layer 9. The stacked alumina layer (2) contains a low-hydrogen content alumina layer, and the low-hydrogen content barrier layer 9 is located outside the stacked alumina layer 2, and the antireflection layer is located outside the low-hydrogen content barrier layer 9. The antireflection layer includes a first silicon nitride layer 3, a second silicon nitride layer 4, a third silicon nitride layer 5, a first silicon oxynitride layer 6, a second silicon oxynitride layer 7, and a silicon oxide layer 8, which are sequentially arranged from the side closest to the stacked alumina layer 2 to the side away from the stacked alumina layer 2. The first silicon nitride layer 3 is a low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3.35 eV and a refractive index of 2.62.

[0095] This embodiment provides a method for preparing a front-side film layer of a solar cell with resistance to UV degradation. It provides a crystalline silicon solar cell with a complete pn junction and currently in normal operation on a production line. The front-side film layer structure needs to be prepared, and the steps are as follows:

[0096] After RCA, the solar cells are deposited with a tandem alumina layer 2 using the ALD process: the deposition temperature is 400℃, the first layer is only circulated with H2O at a flow rate of 18 sccm, a pulse time of 4s, a purge time of 10s, and 5 cycles; the second layer is circulated with TMA and H2O, where the TMA flow rate is 25 sccm, the pulse time is 6s, and the purge time is 10s, and the H2O flow rate is 23 sccm, the pulse time is 6s, and the purge time is 10s, and the TMA and H2O cycle is circulated 25 times; the third layer is circulated with TMA and H2O, where the TMA flow rate is 25 sccm, the pulse time is 6s, and the purge time is 10s, and the H2O flow rate is 20 sccm, the pulse time is 6s, and the purge time is 10s, and the TMA and H2O cycle is circulated 15 times.

[0097] A barrier layer 9 was first deposited on the surface of the low-hydrogen-content stacked alumina film 2 using an ALD process. The deposition temperature was 400℃, the SiH4 inlet flow rate was 2000 sccm, the NH3 inlet flow rate was 13500 sccm, Eg=3.78eV, n=2.09, and the thickness was 6nm.

[0098] Then, an antireflection layer (7 layers) is deposited using PECVD: the first low-bandgap, high-refractive-index silicon nitride layer 3: SiH4 inlet rate 2800 sccm, NH3 inlet rate 7000 sccm, Eg=3.35eV, n=2.62, thickness 11nm; the second silicon nitride layer 4: SiH4 inlet rate 1700 sccm, NH3 inlet rate 10000 sccm, thickness 12nm; the third silicon nitride layer 5: SiH4 inlet rate 1200 sccm, NH3 inlet rate 12000 sccm. The antireflection layer has a thickness of 20 nm and a diameter of 1 cm. The first silicon oxynitride layer 6 has a SiH4 inlet flow rate of 1000 sccm, an NH3 inlet flow rate of 5000 sccm, and an N2O inlet flow rate of 7000 sccm, with a thickness of 10 nm. The second silicon oxynitride layer 7 has a SiH4 inlet flow rate of 1000 sccm, an NH3 inlet flow rate of 4000 sccm, and an N2O inlet flow rate of 9000 sccm, with a thickness of 11 nm. The silicon oxide layer 8 has a SiH4 inlet flow rate of 800 sccm, an N2O inlet flow rate of 11000 sccm, and a thickness of 7 nm. After the antireflection layer deposition process is completed, the following is obtained: Figure 2 The front film structure of the battery is shown.

[0099] Comparative Example 1

[0100] This comparative example provides a method for preparing a front-side film layer of a solar cell with resistance to UV degradation. The difference between this method and Example 1 is that it uses a conventional ALD process to deposit an alumina film layer. Specifically:

[0101] After RCA, the solar cell is deposited with an alumina layer (conventional process): The alumina layer deposition is divided into two layers: the deposition temperature is 200℃, the first layer is only circulated with H2O at a flow rate of 24 sccm and a pulse time of 6.5s, and the cycle is 5 times; the second layer is circulated with TMA and H2O, where the TMA flow rate is 24 sccm and the pulse time is 6s, and the H2O flow rate is 24 sccm and the pulse time is 6.5s, and the deposition is repeated 33 times.

[0102] The remaining process steps and parameters are consistent with those in Example 1.

[0103] Comparative Example 2

[0104] This comparative example provides a method for preparing a front-side film layer of a solar cell with anti-UV degradation effect. The difference between this method and Example 1 is that a conventional PECVD process is used to deposit an anti-reflection layer, which does not contain a low-bandgap, high-refractive-index silicon nitride layer. Specifically, the first layer is a silicon nitride layer deposited by a conventional process, with a SiH4 inlet rate of 2100 sccm, an NH3 inlet rate of 9900 sccm, a thickness of 15 nm, Eg=3.61 eV, and n=2.09. The remaining process steps and parameters are consistent with those of Example 1.

[0105] Comparative Example 3

[0106] This comparative example provides a method for preparing a front-side film layer of a solar cell with anti-UV degradation effect. The difference between this method and Example 4 is that a conventional ALD process is used to deposit an aluminum oxide film layer, and a conventional PECVD process is used to deposit an anti-reflection layer. This anti-reflection layer does not contain a low-bandgap, high-refractive-index silicon nitride layer.

[0107] Alumina deposition (conventional process): The alumina deposition is divided into two layers: the deposition temperature is 200℃, the first layer is only circulated with H2O at a flow rate of 24 sccm and a pulse time of 6.5s, and the cycle is 5 times; the second layer is circulated with TMA and H2O, where the TMA flow rate is 24 sccm and the pulse time is 6s, and the H2O flow rate is 24 sccm and the pulse time is 6.5s, and the deposition is repeated 33 times.

[0108] Depositing an antireflection layer (conventional process), excluding a low-bandgap, high-refractive-index silicon nitride layer: Specifically, compared to Example 4, the first layer of this antireflection layer is a silicon nitride layer deposited by a conventional process, with a SiH4 inlet flow rate of 2200 sccm, an NH3 inlet flow rate of 9800 sccm, a thickness of 11 nm, Eg=3.7 eV, and n=1.8.

[0109] The remaining process steps and parameters are consistent with those in Example 4.

[0110] The front film structures of the batteries prepared in Examples 1-5 and Comparative Examples 1-3 were processed normally according to the production line process to prepare the back film structures. After screen printing UV 60kWh, the electrical performance data were tested, and the data are shown in Table 1.

[0111] Table 1. Battery test results for the examples and comparative examples.

[0112] Eta (%) Uoc(mV) Isc(A) FF (%) Rs (Ω) UV 60kWh attenuation rate (%) Example 1 26.15 730.47 14.089 85.21 1.253 0.19 Example 2 26.14 730.38 14.088 85.21 1.221 0.23 Example 3 26.14 730.43 14.089 85.22 1.235 0.23 Example 4 26.16 730.57 14.0920 85.23 1.231 0.15 Example 5 26.17 730.48 14.090 85.21 1.243 0.11 Comparative Example 1 26.00 731.18 14.080 85.19 1.261 0.76 Comparative Example 2 26.05 731.16 14.070 85.14 1.264 0.57 Comparative Example 3 26.13 731.18 14.081 85.10 1.273 0.65

[0113] Performance test data conclusions and analysis:

[0114] As shown in the table above, the solar cells containing the front-side film structure prepared in Examples 1-5 of this application all have an efficiency ≥26.14% and a UV decay rate ≤0.23%. Compared with Comparative Examples 1-3, their electrical performance parameters are basically the same, but the UV decay rate is significantly reduced. Specific analysis is as follows:

[0115] 1. Efficiency Comparison: The battery efficiency of Examples 1-5 is ≥26.14%;

[0116] The efficiencies (Eta) of Examples 1-5 were 26.15%, 26.14%, 26.14%, 26.16%, and 26.17%, respectively, all remaining above 26.14%, showing no significant difference from the efficiencies of Comparative Examples 1-3 (26.00%, 26.05%, and 26.13%). This application, by optimizing the film structure (such as the synergy between a low-bandgap, high-refractive-index silicon nitride layer and a low-hydrogen-content alumina layer) and process parameters (such as the water flux and water pulse time control for ALD-deposited alumina), achieved improved UV resistance without sacrificing the initial battery efficiency (open-circuit voltage Uoc, short-circuit current Isc, fill factor FF, etc., are all maintained at high levels), thus resolving the problem of "the contradiction between UV resistance degradation and efficiency" in the prior art.

[0117] 2. Comparison of UV attenuation resistance: The UV attenuation rate of Examples 1-5 was ≤0.23%, while that of Comparative Examples 1-3 was as high as 0.57%~0.76%;

[0118] The UV 60kWh attenuation rates of Examples 1-5 were 0.19%, 0.23%, 0.23%, 0.15%, and 0.11%, respectively, all ≤0.23%. In contrast, the attenuation rates of Comparative Examples 1-3 (using conventional alumina processes or conventional antireflection layers) were 2.4 to 6.9 times higher than the Examples (e.g., the 0.76% of Comparative Example 1 was 4 times that of Example 1). The synergistic design of the low-bandgap, high-refractive-index silicon nitride layer (which preferentially absorbs UV photons, reducing silicon substrate damage) and the low-hydrogen-content alumina layer (which inhibits hydrogen diffusion and passivation bond damage) in this application effectively suppresses passivation layer damage caused by UV irradiation, reducing the UV attenuation rate to 1 / 4 to 1 / 7 of that of conventional processes, significantly improving anti-attenuation capability.

[0119] 3. Necessity of a low-hydrogen-content alumina layer: The electrical performance parameters (Uoc: 731.18mV vs 730.47mV, Isc: 14.080A vs 14.089A) of Comparative Example 1 (conventional alumina process) are basically the same as those of Example 1, but the UV decay rate of Comparative Example 1 (0.76%) is 4 times that of Example 1 (0.19%); the electrical performance parameters (Eta: 26.13% vs 26.16%, Uoc: 731.18mV vs 730.57mV) of Comparative Example 3 (conventional alumina process) are close to those of Example 4, but the decay rate of Comparative Example 3 (0.65%) is 4.3 times that of Example 4 (0.15%).

[0120] Conventional alumina deposition processes do not control the water flux and pulse time. The aluminum source flux is the same as the water flux, but the aluminum source pulse time is slightly shorter than the water pulse time. This results in a high content of hydroxyl groups (-OH) and adsorbed water (H2O) in the film. Under UV irradiation, hydrogen atoms easily diffuse to the silicon interface, disrupting the Si-H passivation bonds. In contrast, this application controls the water flux and pulse time during the deposition process to be lower than those of the aluminum source. The reduction in water flux is 1 sccm to 10 sccm, and the reduction in water pulse time is 0.5 s to 4 s. This reduces the hydrogen content in the alumina film, decreases UV-induced secondary hydrogen distribution, and thus maintains the stability of the passivation layer.

[0121] Therefore, the low hydrogen content alumina layer is the core factor in reducing UV decay rate, and it maintains the stability of the passivation layer by regulating the hydrogen content.

[0122] 4. Necessity of the barrier layer: The UV attenuation rate of Examples 1-3 (without a barrier layer) was 0.19%~0.23% (average 0.21%), while the attenuation rate of Examples 4-5 (with a barrier layer) was 0.15%~0.11% (average 0.13%), representing an improvement of approximately 38% in UV resistance;

[0123] The barrier layer (refractive index 1.65-2.1) has a dual function: ① UV photon blocking: by matching the refractive index gradient, it reduces the penetration of UV photons into the silicon substrate, directly reducing interface damage; ② Hydrogen diffusion suppression: as a physical barrier, it prevents hydrogen in the low bandgap silicon nitride layer from migrating to the silicon interface, forming a "double-layer hydrogen management mechanism" with the low hydrogen content alumina.

[0124] Therefore, the introduction of the blocking layer further enhances the UV attenuation resistance through the synergistic effect of "UV photon blocking + hydrogen diffusion suppression", which can reduce the attenuation rate by an additional 38%.

[0125] This application precisely captures and absorbs the energy of UV photons by setting an antireflection layer containing a low-bandgap, high-refractive-index silicon nitride layer, reducing UV damage to the silicon substrate interface. Simultaneously, a stacked alumina layer containing a low-hydrogen-content alumina layer blocks the diffusion of active hydrogen to the silicon substrate interface. Furthermore, a barrier layer can be inserted between the stacked alumina layer and the silicon nitride layer as a hydrogen diffusion barrier, further maintaining the passivation stability of the solar cell. Moreover, this application eliminates the need for additional annealing processes; by adjusting the film layers, through synergistic effects, it reduces interfacial hydrogen concentration to suppress hot carrier destruction and reduces light reflection loss through pre-photon absorption and refractive index matching, thereby improving resistance to UV degradation while maintaining photoelectric conversion efficiency.

[0126] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A front-side film layer for a solar cell with resistance to UV degradation, characterized in that, The material includes an antireflection layer and a stacked alumina layer (2), with the antireflection layer located outside the stacked alumina layer (2); the antireflection layer includes a low-bandgap, high-refractive-index silicon nitride layer, the bandgap of which is 3eV~3.6eV, the refractive index is 2.1~2.8, and the thickness accounts for 5%~30% of the thickness of the antireflection layer; the stacked alumina layer (2) includes a low-hydrogen-content alumina layer, which is deposited using an ALD process, wherein the low-hydrogen-content alumina layer is obtained by reducing the water flux and / or water pulse time during the deposition process; The methods for reducing water flux include: canceling the deposition process of the first layer of water in the deposition process of the stacked alumina layer (2), and / or reducing the water flux of any one layer of the deposition process in the stacked alumina layer (2), and / or reducing the water flux of at least one layer of the deposition process in the stacked alumina layer (2); wherein, the film layer in the stacked alumina layer (2) for which water flux is reduced is the low-hydrogen-content alumina layer, and during the deposition process of the low-hydrogen-content alumina layer, the aluminum source flux is 16 sccm~26 sccm, and the water flux is 6 sccm~25 sccm; relative to the aluminum source flux, the reduction in water flux is 1 sccm~10 sccm; The reduction of water pulse time includes: reducing the water pulse time of any one of the deposition processes in the stacked alumina layers (2), and / or reducing the water pulse time of at least one deposition process in the stacked alumina layers (2); wherein, the film layer in the stacked alumina layers (2) for reducing water pulse time is the low-hydrogen-content alumina layer, and during the deposition process of the low-hydrogen-content alumina layer, the aluminum source pulse time is 4s~8s and the water pulse time is 0.5s~7.5s; the reduction in water pulse time relative to the aluminum source pulse time is 0.5s~4s.

2. The front-side film layer of a solar cell with anti-UV degradation effect according to claim 1, characterized in that, It also includes a low-hydrogen-content barrier layer (9) located between the stacked alumina layer (2) and the low-bandgap, high-refractive-index silicon nitride layer, the refractive index of the barrier layer (9) being 1.65 to 2.

1.

3. The front-side film layer of a solar cell with anti-UV degradation effect according to claim 2, characterized in that, The material of the barrier layer (9) is Si. x O y Si x N y and Si x O y N z Any of the following, with a thickness of 1nm to 10nm.

4. The front-side film layer of a solar cell with anti-UV degradation effect according to claim 1, characterized in that, The thickness of the stacked alumina layer (2) is 2nm~10nm, and it contains at least one alumina layer with low hydrogen content.

5. The front-side film layer of a solar cell with anti-UV degradation effect according to claim 1, characterized in that, The antireflective layer is made of Si. x O y Si x N y and Si x O y N z One or more of the following; the material of the low-bandgap, high-refractive-index silicon nitride layer is Si. x N y The thickness is 5nm~30nm.

6. The front-side film layer of a solar cell with anti-UV degradation effect according to claim 1, characterized in that, The antireflection layer comprises a first silicon nitride layer (3), a second silicon nitride layer (4), a third silicon nitride layer (5), a first silicon oxynitride layer (6), a second silicon oxynitride layer (7), and a silicon oxide layer (8) arranged sequentially from the side closest to the stacked alumina layer (2) to the side furthest from the stacked alumina layer (2).

7. The front-side film layer of a solar cell with anti-UV degradation effect according to claim 6, characterized in that, The first silicon nitride layer (3) is a silicon nitride layer with low band gap and high refractive index, or the second silicon nitride layer (4) is a silicon nitride layer with low band gap and high refractive index, or the third silicon nitride layer (5) is a silicon nitride layer with low band gap and high refractive index.

8. A method for preparing a front-side film layer of a solar cell with UV-resistant degradation effect as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: A multilayer aluminum oxide layer (2) is deposited on the front side of the battery cell using the ALD process, with a deposition temperature of 200℃~350℃; S2: An anti-reflection layer is deposited on the outer surface of the stacked alumina layer (2) by PECVD process. During the deposition process, the ratio of SiH4 to NH3 intake is 24%~60%, and the deposition temperature is 200℃~600℃.

9. The preparation method according to claim 8, characterized in that, It also includes a barrier layer (9) deposition step between S1 and S2, wherein the barrier layer (9) is deposited by PECVD process, and during the deposition process, the ratio of SiH4 to NH3 intake is 5%~23%, and the deposition temperature is 200℃~600℃.

10. A solar cell, characterized in that, The solar cell includes the front film layer of any one of claims 1-7, wherein the solar cell is a TOPCon cell or a BC cell.

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