Solar cell front film layer with anti-UV attenuation effect and preparation method thereof

Abstract

The invention relates to the technical field of solar cells, and particularly discloses a solar cell front film layer with an anti-UV attenuation effect and a preparation method. The front film layer comprises an antireflection layer and a laminated aluminum oxide layer, and the antireflection layer is located on the outer side of the laminated aluminum oxide layer; the antireflection layer comprises a silicon nitride layer with low band gap and high refractive index; the laminated aluminum oxide layer (2) comprises a low-hydrogen-content aluminum oxide layer, the laminated aluminum oxide layer is deposited by adopting an ALD (Atomic Layer Deposition) process, and the low-hydrogen-content aluminum oxide layer is obtained by reducing the water flux and / or water pulse time in the deposition process. The silicon nitride layer with the low band gap and the high refractive index captures and absorbs energy of UV photons, damage of UV to a silicon substrate interface is reduced, and the aluminum oxide layer with the low hydrogen content blocks diffusion of active hydrogen to the silicon substrate interface; through the synergistic effect of the film layers, the photoelectric conversion efficiency is ensured, and meanwhile, the ultraviolet attenuation resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell front film layer with anti-UV attenuation effect and a preparation method thereof. Background Art

[0002] As a clean, renewable energy source, solar energy is increasingly being used in the energy sector. Solar cells are the core devices that convert solar energy into electricity, and their efficiency and stability are important indicators of solar cell performance. However, ultraviolet (UV) attenuation can adversely affect solar cell performance.

[0003] UV attenuation causes some high-energy light energy to be unusable by photovoltaic cells, thereby reducing their power generation efficiency. This is the main problem that causes the efficiency of photovoltaic cells to decrease after long-term exposure to UV radiation. Its mechanisms include:

[0004] 1. Si passivation damage: UV photons (280-400nm) inject electrons into the SiO2 interface, which will increase the recombination centers of the Si / SiO2 interface, change the fixed charge density and increase the interface defect density 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 destroys the Si-H bond at the interface, and the secondary distribution of hydrogen leads to excess H atomic groups, which promotes the recombination of carriers.

[0007] To address the UV attenuation issue for batteries, existing technologies typically employ single measures, such as increasing the thickness of aluminum oxide, improving the refractive index of silicon nitride films, or reducing the refractive index of silicon nitride. However, these measures significantly reduce the passivation performance of the cell (reduced Uoc and Isc), as well as the efficiency of the cell and result in poor UV resistance. Furthermore, existing technologies also suffer from the following defects: The film layer has a single function and cannot balance UV absorption and hydrogen management; UV attenuation and cell efficiency cannot be reconciled, making mass production impossible.

[0008] Therefore, there is an urgent need for a technical solution that can effectively improve the ability of solar cells to resist UV attenuation effects without reducing cell efficiency. Summary of the Invention

[0009] This application is aimed at the above problems and provides a solar cell front film layer with anti-UV attenuation effect and a preparation method to solve the problem in the existing technology that UV attenuation and cell efficiency cannot be taken into account at the same time, and to improve the anti-UV attenuation ability of the cell while minimizing the reduction in cell efficiency.

[0010] This application is implemented through the following technical solutions:

[0011] The present application provides a solar cell front film layer with an anti-UV attenuation effect, comprising an anti-reflection layer and a laminated aluminum oxide layer, wherein the anti-reflection layer is located outside the laminated aluminum oxide layer; the anti-reflection 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 to 3.6eV, the refractive index is 2.1 to 2.8, and the thickness accounts for 5% to 30% of the thickness of the anti-reflection layer; the laminated aluminum oxide layer (2) comprises an aluminum oxide layer with a low hydrogen content, wherein the laminated aluminum oxide layer is deposited by an ALD process, wherein the aluminum oxide layer with a low hydrogen content is obtained by reducing the water flux and / or the 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 pairs a low-bandgap, high-refractive-index silicon nitride layer with a low-hydrogen-content aluminum oxide layer, reducing the interfacial hydrogen concentration to suppress hot-carrier damage and reducing light reflection losses through pre-photon absorption and refractive index matching. This ensures photoelectric conversion efficiency while also improving UV attenuation resistance. Specifically, a low-bandgap, high-refractive-index silicon nitride layer with a bandgap of 3eV to 3.6eV and a refractive index of 2.1 to 2.8 (common silicon nitride has a refractive index of 1.8 to 2.0) can improve absorption of UV light in the 280nm to 400nm band, reducing UV damage to the silicon substrate passivation. However, this also means that the silicon nitride layer contains a high hydrogen content. The low-hydrogen-content aluminum oxide layer can capture the high hydrogen content in the silicon nitride layer, preventing it from binding to the silicon substrate and reducing Si-H bond breakage. This reduces UV attenuation while maintaining the initial cell efficiency.

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

[0014] Furthermore, the film layer for reducing water flux in the stacked aluminum oxide layer (2) is the aluminum oxide layer with low hydrogen content; during the deposition process of the aluminum oxide layer with low hydrogen content, the aluminum source flux is 16 sccm to 26 sccm, and the water flux is 6 sccm to 25 sccm, and the reduction in water flux relative to the aluminum source flux is 1 sccm to 10 sccm. 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 water pulse time is reduced in a manner including: reducing the water pulse time of a deposition process of any one layer of the laminated aluminum oxide layer (2), and / or reducing the water pulse time of a deposition process of at least one layer of the laminated aluminum oxide layer (2).

[0016] Furthermore, the film layer that reduces the water pulse time in the laminated aluminum oxide layer (2) is the aluminum oxide layer with a low hydrogen content; during the deposition process of the aluminum oxide layer with a low hydrogen content, the aluminum source pulse time is 4s to 8s, and the water pulse time is 0.5s to 7.5s. Compared with the aluminum source pulse time, the reduction in the water pulse time is 0.5s to 4s. 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, a barrier layer with low hydrogen content is included, the barrier layer being located between the laminated aluminum oxide layer and the low-bandgap, high-refractive-index silicon nitride layer, and 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] The present application sets a barrier layer to block the penetration of high-energy ultraviolet rays, and at the same time acts as a hydrogen diffusion barrier to further maintain the passivation stability and reduce the diffusion of hydrogen 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 The thickness of the cathode layer can be 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, 10 nm, etc.

[0021] Furthermore, the laminated aluminum oxide layer has a thickness of 2 nm to 10 nm and includes at least one low-hydrogen content aluminum oxide layer. The thickness of the laminated aluminum oxide layer can be 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, etc.; the number of low-hydrogen content aluminum oxide layers can be one, two, three, four, five, etc.

[0022] Furthermore, the material of the anti-reflection layer is 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 band gap high refractive index silicon nitride layer is Si x N y The thickness of the low-bandgap, high-refractive-index silicon nitride layer may be 5 nm, 9 nm, 10 nm, 15 nm, 18 nm, 20 nm, 25 nm, 27 nm, 30 nm, etc.

[0023] Furthermore, the anti-reflection layer includes 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 arranged from the side close to the laminated aluminum oxide layer to the side away from the laminated aluminum oxide layer.

[0024] Furthermore, the first silicon nitride layer is a low-bandgap high-refractive-index silicon nitride layer, or the second silicon nitride layer is a low-bandgap high-refractive-index silicon nitride layer, or the third silicon nitride layer is a low-bandgap high-refractive-index silicon nitride layer.

[0025] The present application also provides a method for preparing the front film layer of the solar cell, comprising the following steps:

[0026] S1: Aluminum oxide layer is deposited on the front of the cell by ALD process, with the deposition temperature of 200℃~350℃;

[0027] S2: depositing an anti-reflection layer on the outer surface of the laminated aluminum oxide layer by a PECVD process. During the deposition process, the ratio of SiH4 to NH3 inlet volume is 24% to 60%, and the deposition temperature is 200°C to 600°C.

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

[0029] The present application also provides a solar cell, comprising the above-mentioned solar cell front film layer, 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 damage to the passivation layer caused by ultraviolet radiation while maintaining the initial efficiency of the solar cell. Through the synergistic effect of the film layers, the interface hydrogen concentration is reduced to suppress hot carrier damage, and the light reflection loss is reduced through pre-photon absorption and refractive index matching. While ensuring the photoelectric conversion efficiency, the anti-ultraviolet attenuation performance is improved.

[0032] (2) The process of this application is simple and does not require additional steps such as annealing. The process parameters are compatible with existing ALD / PECVD production lines, and no new equipment is required, making it suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0034] Figure 1 Schematic diagram of the front film structure of a solar cell with anti-UV attenuation effect provided in Examples 1-3 of the present application;

[0035] Figure 2 Schematic diagram of the front film structure of a solar cell with anti-UV attenuation effect provided in Examples 4 and 5 of the present invention.

[0036] Description of main reference numerals:

[0037] 1. Silicon substrate; 2. Laminated 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 DESCRIPTION

[0038] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details are not necessarily required to practice the present invention. In other embodiments, well-known materials or methods are not specifically described to avoid obscuring the present invention.

[0039] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and / or subcombinations in one or more embodiments or examples. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] Explanation of terms:

[0041] TOPCon: Tunnel Oxide Passivated Contact (tunneling silicon oxide passivated contact technology);

[0042] BC: Back Contact battery (back contact battery);

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

[0044] ALD: atomic layer deposition;

[0045] RCA: Cleaning process:

[0046] UVID: Ultraviolet Degradation (UV attenuation);

[0047] TMA: trimethylaluminum;

[0048] In 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 band is the UVID test condition, and the photon energy is 3.1eV~4.43eV (λ=1240 / Eg). 3.4eV ultraviolet A (UVA) light around 360nm can destroy Si-H bonds.

[0049] In conventional ALD processes for depositing stacked aluminum oxide layers, the aluminum source flux is equal to the water flux, and the aluminum source pulse time is slightly lower than the water pulse time. The film layer contains high levels of hydroxyl groups (-OH) and adsorbed water (H2O). Under UV irradiation, hydrogen atoms easily diffuse to the silicon interface, destroying the Si-H passivation bond. For example, to deposit a two-layer stacked aluminum oxide layer, a conventional ALD process involves passing only water through the first layer at a flow rate of 24 sccm, a pulse time of 6.5 seconds, and five cycles. Trimethylaluminum (TMA) is used as the aluminum source, and a combination of TMA and water is passed through the second layer at a TMA flow rate of 24 sccm, a pulse time of 6 seconds, and a H2O flow rate of 24 sccm, a pulse time of 6.5 seconds, and 33 cycles.

[0050] In the first aspect, the present application provides a front film layer of a solar cell with an anti-UV attenuation effect, comprising an anti-reflection layer and a laminated aluminum oxide layer 2, and the anti-reflection layer is located on the outside of the laminated aluminum oxide layer 2; the anti-reflection layer comprises a low-bandgap, high-refractive-index silicon nitride layer, 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 anti-reflection layer; the laminated aluminum oxide layer 2 comprises an aluminum oxide layer with a low hydrogen content, and the laminated aluminum oxide layer 2 is deposited using an ALD process, wherein the aluminum oxide layer with a low hydrogen content is obtained by reducing the water flux and / or water pulse time during the deposition process.

[0051] In this application, the "hydrogen" of aluminum oxide mainly exists in the form of hydroxyl groups (-OH), and some remain in the form of physically adsorbed H2O molecules. During ALD deposition, the hydrolysis reaction of the aluminum source precursor (such as TMA) will introduce a large number of -OH bonds; -OH bonds are carriers of hydrogen diffusion and will decompose to generate active hydrogen atoms (H) during high-temperature sintering. 0 ), too high a content will lead to explosive release of hydrogen, which will diffuse to the silicon interface and destroy the Si-H passivation bond; and the H2O molecules that are not fully removed during the deposition process are wrapped in the pores of the film layer and released as H in subsequent processes (such as sintering). + / OH - ions, participate in interfacial reactions.

[0052] The present application provides 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 (the refractive index of conventional silicon nitride is 1.8~2.0) to improve the absorption of UV light in the 280nm~400nm band and reduce the damage of UV light to the passivation of the silicon substrate, but it also means that the silicon nitride layer has a higher hydrogen content; therefore, the low-hydrogen-content aluminum oxide layer 2 is provided. On the one hand, the hydrogen content at the interface between the silicon substrate and the low-hydrogen-content aluminum oxide layer 2 can be reduced; on the other hand, after sintering, the hydrogen in the silicon nitride layer can be captured, preventing it from combining with the silicon substrate and reducing the breakage of the Si-H bond; thereby, the UV attenuation rate is reduced while maintaining the efficiency of the initial cell.

[0053] In a specific embodiment, the method of reducing the water flux includes: canceling the deposition process of the first layer of water in the deposition process of the laminated aluminum oxide layer 2, and / or reducing the water flux of the deposition process of any layer in the laminated aluminum oxide layer 2, and / or reducing the water flux of at least one deposition process in the laminated aluminum oxide layer 2.

[0054] In a specific embodiment, the membrane layer that reduces the water flux in the laminated aluminum oxide layer 2 is an aluminum oxide layer with a low hydrogen content; during the deposition process of the aluminum oxide layer with a low hydrogen content, 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.

[0055] In a specific embodiment, the water pulse time is reduced by reducing the water pulse time of any deposition process of the laminated aluminum oxide layer 2 and / or reducing the water pulse time of at least one deposition process of the laminated aluminum oxide layer 2 .

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

[0057] In a specific embodiment, a barrier layer 9 with low hydrogen content is further included. The barrier layer 9 is located between the laminated aluminum oxide layer 2 and the low-bandgap, high-refractive-index silicon nitride layer. The refractive index of the barrier layer 9 is 1.65-2.1.

[0058] The present application sets a barrier layer 9 with a refractive index between 1.65 and 2.1 to block the penetration of high-energy ultraviolet rays, and at the same time acts as a hydrogen diffusion barrier to maintain the passivation stability of the cell, further reducing the diffusion of hydrogen to the silicon substrate interface.

[0059] In a 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 one of the above, with a thickness of 1nm~10nm.

[0060] In a specific embodiment, the laminated aluminum oxide layer 2 has a thickness of 2 nm to 10 nm and includes at least one aluminum oxide layer with a low hydrogen content.

[0061] In a specific embodiment, the material of the anti-reflection layer is Si x O y 、Six N y and Si x O y N z One or more of; the material of the low band gap high refractive index silicon nitride layer is Si x N y , thickness is 5nm~30nm.

[0062] In a specific embodiment, the anti-reflection layer includes 6 film layers, and 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 arranged in sequence from the side close to the laminated aluminum oxide layer 2 to the side away from the laminated aluminum oxide layer 2.

[0063] In a specific embodiment, the first silicon nitride layer 3 is a low-bandgap high-refractive-index silicon nitride layer, or the second silicon nitride layer 4 is a low-bandgap high-refractive-index silicon nitride layer, or the third silicon nitride layer 5 is a low-bandgap high-refractive-index silicon nitride layer.

[0064] In a second aspect, the present application further provides a method for preparing the front film layer of the solar cell, comprising the following steps:

[0065] S1: Depositing a laminated aluminum oxide layer 2 on the front of the cell by ALD process at a deposition temperature of 200°C to 350°C;

[0066] S2: depositing an anti-reflection layer on the outer surface of the laminated aluminum oxide layer 2 by a PECVD process. During the deposition process, the ratio of SiH4 to NH3 inlet volume is 24% to 60%, and the deposition temperature is 200°C to 600°C.

[0067] The present application reduces the hydroxyl group (-OH) and adsorbed water (H2O) in the deposition process of the laminated aluminum oxide layer 2 through process control, thereby reducing the diffusible hydrogen content. First, in step S1, the laminated aluminum oxide layer 2 including an aluminum oxide layer with a low hydrogen content is realized by optimizing the ALD process parameters: the aluminum oxide layer 2 with a low hydrogen content is obtained by reducing the water flux and / or water pulse time during the deposition process; specifically, the method of reducing the water flux includes canceling the deposition process of the first layer of water in the deposition process of the laminated aluminum oxide layer 2 to avoid initial interface hydrogen enrichment, and / or reducing the water flux of any deposition process of the laminated aluminum oxide layer 2, and / or reducing the water flux of at least one deposition process of the laminated aluminum oxide layer 2; during the deposition process, the film layer in the laminated aluminum oxide layer 2 that reduces the water flux is the aluminum oxide layer with a low hydrogen content, and the aluminum source flux of the aluminum oxide layer with a low hydrogen content is The water flux is 16 sccm to 26 sccm, and the water flux is 6 sccm to 25 sccm. Relative to the aluminum source flux, the water flux is reduced by 1 sccm to 10 sccm. The water pulse time is reduced by reducing the water pulse time during the deposition process of any layer in the laminated aluminum oxide layer 2, and / or reducing the water pulse time during the deposition process of at least one layer in the laminated aluminum oxide layer 2. During the deposition process, the layer in the laminated aluminum oxide layer 2 where the water pulse time is reduced is a low-hydrogen aluminum oxide layer. The aluminum source pulse time for the low-hydrogen aluminum oxide layer is 4s to 8s, and the water pulse time is 0.5s to 7.5s. Relative to the aluminum source pulse time, the water pulse time is reduced by 0.5s to 4s. This allows precise control of the hydroxyl content during the aluminum oxide growth process, reducing the hydrogen atom concentration within the film layer, and thus reducing passivation failure caused by hydrogen secondary distribution under UV irradiation. Secondly, in step S2, by controlling the ratio of the intake volume of SiH4 and NH3 to 24%~60% during the silicon oxide deposition process, 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. The 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, thereby reducing surface reflection while achieving pre-absorption of ultraviolet photons and avoiding damage to the underlying passivation structure; thereby, the performance of maintaining the initial efficiency of the cell while reducing the UV attenuation rate is achieved.

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

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

[0070] In a third aspect, the present application further provides a solar cell comprising the above-mentioned solar cell front film layer, wherein the solar cell is a TOPCon cell or a BC cell.

[0071] The following will clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0072] Example 1

[0073] like Figure 1 As shown, a front film layer of a solar cell with an anti-UV attenuation effect comprises an anti-reflection layer and a laminated aluminum oxide layer 2, wherein the laminated aluminum oxide layer (2) contains an aluminum oxide layer with a low hydrogen content, and the anti-reflection layer is located outside the laminated aluminum oxide layer 2; the anti-reflection 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, which are arranged in sequence from the side close to the laminated aluminum oxide layer 2 to the side away from the laminated aluminum oxide layer 2; wherein the first silicon nitride layer 3 is a low-bandgap and high-refractive-index silicon nitride layer, whose bandgap is 3.3 eV and the refractive index is 2.7.

[0074] This embodiment provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. To provide a crystalline silicon cell with normal production line flow and complete pn junction, it is necessary to prepare a front film layer structure. The steps are as follows:

[0075] The cell after RCA is subjected to an ALD process to deposit a laminated aluminum oxide film layer 2: the deposition temperature is 200°C, the first layer is passed through only H2O with a flow rate of 20 sccm, a pulse time of 4 s, a purge time of 10 s, and a cycle of 5 times; the second layer is passed through a cycle of trimethylaluminum TMA and H2O, wherein the flow rate of trimethylaluminum TMA is 20 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 15 sccm, the pulse time is 6 s, the purge time is 10 s, the cycle of trimethylaluminum TMA and H2O is passed 33 times, and the thickness of the low-hydrogen-content aluminum oxide layer 2 is 6 nm.

[0076] Deposit the anti-reflection layer (7 layers) by PECVD process: Deposit the first low-bandgap, high-refractive-index silicon nitride layer 3: SiH4 gas flow rate is 3000sccm, NH3 gas flow rate is 7000sccm, Eg=3.3eV, n=2.7, thickness is 11nm; the second silicon nitride layer 4: SiH4 gas flow rate is 1700sccm, NH3 gas flow rate is 10000sccm, thickness is 12nm; the third silicon nitride layer 5: SiH4 gas flow rate is 1200sccm, NH3 gas flow rate is 12000sccm cm, with a thickness of 20nm; the first silicon oxynitride layer 6: SiH4 intake volume is 1000sccm, NH3 intake volume is 5000sccm, N2O intake volume is 7000sccm, and the thickness is 10nm; the second silicon oxynitride layer 7: SiH4 intake volume is 1000sccm, NH3 intake volume is 4000sccm, N2O intake volume is 9000sccm, and the thickness is 11nm; the silicon oxide layer 8: SiH4 intake volume is 800sccm, N2O intake volume is 11000sccm, and the thickness is 7nm. After the anti-reflection layer deposition process is completed, the following is obtained Figure 1 The film structure on the front of the battery is shown.

[0077] Example 2

[0078] like Figure 1 As shown, a front film layer of a solar cell with an anti-UV attenuation effect comprises an anti-reflection layer and an aluminum oxide layer 2 with a low hydrogen content, wherein the laminated aluminum oxide layer (2) contains an aluminum oxide layer with a low hydrogen content, and the anti-reflection layer is located outside the laminated aluminum oxide layer 2; the anti-reflection 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, which are sequentially arranged from a side close to the laminated aluminum oxide layer 2 to a side away from the laminated aluminum oxide layer 2; wherein the second silicon nitride layer 4 is a low-bandgap, high-refractive-index silicon nitride layer, whose bandgap is 3.3 eV and whose refractive index is 2.7.

[0079] This embodiment provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. To provide a crystalline silicon cell with normal production line flow and complete pn junction, it is necessary to prepare a front film layer structure. The steps are as follows:

[0080] The cell after RCA is deposited with a stacked aluminum oxide layer 2 by an ALD process: the deposition temperature is 250°C, the first layer is subjected to a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 25 sccm, the pulse time is 6 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 20 times; the second layer is subjected to a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 20 sccm, the pulse time is 6 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 13 times, with a thickness of 6 nm.

[0081] The anti-reflection layer was deposited by PECVD process (7 layers): the first silicon nitride layer: SiH4 gas flow rate was 2300 sccm, NH3 gas flow rate was 9800 sccm, the thickness was 15 nm, Eg = 3.6 eV, n = 2.0; the second silicon nitride layer (low band gap and high refractive index): SiH4 gas flow rate was 3000 sccm, NH3 gas flow rate was 7000 sccm, Eg = 3.3 eV, n = 2.7, the thickness was 11 nm; the third silicon nitride layer 5: SiH4 gas flow rate was 1200 sccm, NH3 gas flow rate was 12000 sccm, the thickness was 20 nm; the first Si x O y N z Layer 6: SiH4 gas flow rate is 1000sccm, NH3 gas flow rate is 5000sccm, N2O gas flow rate is 7000sccm, thickness is 10nm; the second Si x O y N z Layer 7: SiH4 gas flow rate is 1000sccm, NH3 gas flow rate is 4000sccm, N2O gas flow rate is 9000sccm, thickness is 11nm; Si x O y Layer 8: SiH4 gas flow rate is 800sccm, N2O gas flow rate is 11000sccm, thickness is 7nm. After the anti-reflection layer deposition process is completed, the following is obtained: Figure 1 The film structure on the front of the battery is shown.

[0082] Example 3

[0083] like Figure 1As shown, a front film layer of a solar cell with an anti-UV attenuation effect comprises an anti-reflection layer and a laminated aluminum oxide layer 2 with a low hydrogen content, wherein the laminated aluminum oxide layer (2) contains an aluminum oxide layer with a low hydrogen content, and the anti-reflection layer is located outside the laminated aluminum oxide layer 2; the anti-reflection 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, which are sequentially arranged from a side close to the laminated aluminum oxide layer 2 to a side away from the laminated aluminum oxide layer 2; wherein the third silicon nitride layer 5 is a low-bandgap, high-refractive-index silicon nitride layer, with a bandgap of 3.3 eV and a refractive index of 2.7.

[0084] This embodiment provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. To provide a crystalline silicon cell with normal production line flow and complete pn junction, it is necessary to prepare a front film layer structure. The steps are as follows:

[0085] The cell after RCA is deposited with a stacked aluminum oxide layer 2 by an ALD process: the deposition temperature is 350°C, the first layer is passed through only H2O with a flow rate of 23 sccm, a pulse time of 6 s, a purge time of 10 s, and a cycle of 5 times; the second layer is passed through a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 20 sccm, the pulse time is 4 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 25 times; the third layer is passed through a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 16 sccm, the pulse time is 3 s, the purge time is 8 s, and the cycle of TMA and H2O is passed 15 times.

[0086] Anti-reflection layers (7 layers) were deposited by PECVD process: first silicon nitride layer: SiH4 gas flow rate was 2300 sccm, NH3 gas flow rate was 9800 sccm, thickness was 15nm, Eg=3.6eV, n=2.0; second silicon nitride layer (low band gap and high refractive index): SiH4 gas flow rate was 3000 sccm, NH3 gas flow rate was 7000 sccm, Eg=3.3eV, n=2.7, thickness was 11nm; third silicon nitride layer 5: SiH4 gas flow rate was 1200 sccm, NH3 gas flow rate was 12000 sccm, thickness was 20nm; first silicon oxynitride layer 6: SiH4 The gas flow rate is 1000sccm, the NH3 gas flow rate is 5000sccm, the N2O gas flow rate is 7000sccm, and the thickness is 10nm; the second silicon oxynitride layer 7: the SiH4 gas flow rate is 1000sccm, the NH3 gas flow rate is 4000sccm, the N2O gas flow rate is 9000sccm, and the thickness is 11nm; the silicon oxide layer 8: the SiH4 gas flow rate is 800sccm, the N2O gas flow rate is 11000sccm, and the thickness is 7nm. After the anti-reflection layer deposition process is completed, the following is obtained: Figure 1 The film structure on the front of the battery is shown.

[0087] Example 4

[0088] like Figure 2 As shown, a solar cell front film layer with anti-UV attenuation effect includes a laminated aluminum oxide layer 2, an anti-reflection layer and a low-hydrogen content barrier layer 9, wherein the laminated aluminum oxide layer (2) contains a low-hydrogen content aluminum oxide layer, the low-hydrogen content barrier layer 9 is located outside the laminated aluminum oxide layer 2, and the anti-reflection layer is located outside the low-hydrogen content barrier layer 9; 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 arranged in sequence from the side close to the laminated aluminum oxide layer 2 to the side away from the laminated aluminum oxide layer 2; wherein the first silicon nitride layer 3 is a low-bandgap and high-refractive-index silicon nitride layer, whose bandgap is 3.35 eV and the refractive index is 2.62.

[0089] This embodiment provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. To provide a crystalline silicon cell with normal production line flow and complete pn junction, it is necessary to prepare a front film layer structure. The steps are as follows:

[0090] The cell after RCA is deposited with a stacked aluminum oxide layer 2 by an ALD process: the deposition temperature is 250°C, the first layer is subjected to a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 25 sccm, the pulse time is 3 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 20 times; the second layer is subjected to a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 20 sccm, the pulse time is 6 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 13 times, with a thickness of 6 nm.

[0091] A barrier layer 9 is first deposited on the surface of the low-hydrogen-content laminated aluminum oxide layer 2 by a PECVD process, with a deposition temperature of 250°C, a SiH4 gas flow rate of 1400 sccm, an NH3 gas flow rate of 28000 sccm, Eg=3.8eV, n=2.08, and a thickness of 3.5nm.

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

[0093] Example 5

[0094] like Figure 2As shown, a solar cell front film layer with anti-UV attenuation effect includes a laminated aluminum oxide layer 2, an anti-reflection layer and a low-hydrogen content barrier layer 9, wherein the laminated aluminum oxide layer (2) contains a low-hydrogen content aluminum oxide layer, the low-hydrogen content barrier layer 9 is located outside the laminated aluminum oxide layer 2, and the anti-reflection layer is located outside the low-hydrogen content barrier layer 9; 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 arranged in sequence from the side close to the laminated aluminum oxide layer 2 to the side away from the laminated aluminum oxide layer 2; wherein the first silicon nitride layer 3 is a low-bandgap and high-refractive-index silicon nitride layer, whose bandgap is 3.35 eV and the refractive index is 2.62.

[0095] This embodiment provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. To provide a crystalline silicon cell with normal production line flow and complete pn junction, it is necessary to prepare a front film layer structure. The steps are as follows:

[0096] The cell after RCA is deposited with a stacked aluminum oxide layer 2 by an ALD process: the deposition temperature is 400°C, the first layer is passed through only H2O, with a flow rate of 18 sccm, a pulse time of 4 s, a purge time of 10 s, and a cycle of 5 times; the second layer is passed through a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 23 sccm, the pulse time is 6 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 25 times; the third layer is passed through a cycle of TMA and H2O, wherein the flow rate of TMA is 25 sccm, the pulse time is 6 s, the purge time is 10 s, the flow rate of H2O is 20 sccm, the pulse time is 6 s, the purge time is 10 s, and the cycle of TMA and H2O is passed 15 times.

[0097] A barrier layer 9 is first deposited on the surface of the low-hydrogen-content laminated aluminum oxide film 2 by an ALD process. The deposition temperature is 400°C, the SiH4 gas flow rate is 2000sccm, the NH3 gas flow rate is 13500sccm, Eg=3.78eV, n=2.09, and the thickness is 6nm.

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

[0099] Comparative Example 1

[0100] This comparative example provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. The difference between this method and Example 1 is that a conventional ALD process is used to deposit an aluminum oxide film layer, specifically:

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

[0102] The remaining process steps and parameters remained the same as in Example 1.

[0103] Comparative Example 2

[0104] This comparative example provides a method for preparing a front film layer of a solar cell with an anti-UV attenuation effect. The difference between the method and Example 1 is that a conventional PECVD process is used to deposit an anti-reflection layer, and the anti-reflection layer does not include 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 gas intake rate of 2100 sccm, an NH3 gas intake 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 in Example 1.

[0105] Comparative Example 3

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

[0107] Deposition of aluminum oxide layer (conventional process): The aluminum oxide layer deposition is divided into two layers: the deposition temperature is 200°C, and the first layer is passed through only H2O with a flow rate of 24 sccm, a pulse time of 6.5 s, and 5 cycles; the second layer is passed through TMA and H2O, where the TMA flow rate is 24 sccm, the pulse time is 6 s, and the H2O flow rate is 24 sccm, the pulse time is 6.5 s, and deposition is performed 33 times.

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

[0109] The remaining process steps and parameters remain the same as those in Example 4.

[0110] The front film structure of the battery prepared in Examples 1-5 and Comparative Examples 1-3 was circulated normally, and the back film structure was prepared according to the production line process and screen-printed with UV60kWh. The electrical performance data was tested, and the data are shown in Table 1:

[0111] Table 1 Test results of batteries of Examples and Comparative Examples

[0112] Eta (%) Uoc (mV) Isc (A) FF (%) Rs (Ω) UV60kWh 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 conclusion analysis:

[0114] As can be seen from the table above, the efficiency of the cells containing the front film structures prepared in Examples 1-5 of the present application is ≥26.14%, and the UV attenuation rate is ≤0.23%. Compared with Comparative Examples 1-3, their electrical performance parameters are basically the same, and the UV attenuation rate is significantly reduced. The 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 maintaining levels above 26.14%, and showing no significant difference from the efficiencies of Comparative Examples 1-3 (26.00%, 26.05%, and 26.13%). By optimizing the film structure (e.g., the synergy between the low-bandgap, high-refractive-index silicon nitride layer and the low-hydrogen-content aluminum oxide layer) and process parameters (e.g., the water flux and water pulse duration control for ALD-deposited aluminum oxide), this application achieves improved UV resistance without sacrificing the initial efficiency of the cell (maintaining high parameters such as open-circuit voltage Uoc, short-circuit current Isc, and fill factor FF), thus resolving the conflict between UV resistance and efficiency found in the prior art.

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

[0118] The UV60kWh attenuation rates of Examples 1-5 were 0.19%, 0.23%, 0.23%, 0.15%, and 0.11%, respectively, all ≤0.23%. Comparative Examples 1-3 (using conventional alumina processes or conventional anti-reflection layers) achieved attenuation rates 2.4 to 6.9 times higher than those of the Examples (e.g., the 0.76% rate in Comparative Example 1 is four times that of Example 1). The collaborative design of the low-bandgap, high-refractive-index silicon nitride layer (which preferentially absorbs UV photons and reduces damage to the silicon substrate) and the low-hydrogen-content aluminum oxide layer (which inhibits hydrogen diffusion and damage to the passivation bonds) in this application effectively inhibits UV irradiation-induced damage to the passivation layer, reducing the UV attenuation rate to 1 / 4 to 1 / 7 of that of conventional processes, significantly improving attenuation resistance.

[0119] 3. Necessity of a Low-Hydrogen Aluminum Oxide Layer: The electrical performance parameters of Comparative Example 1 (conventional alumina process) are essentially the same as those of Example 1 (Uoc: 731.18 mV vs. 730.47 mV, Isc: 14.080 A vs. 14.089 A), but the UV attenuation rate of Comparative Example 1 (0.76%) is four times that of Example 1 (0.19%). The electrical performance parameters of Comparative Example 3 (conventional alumina process) are similar to those of Example 4 (Eta: 26.13% vs. 26.16%, Uoc: 731.18 mV vs. 730.57 mV), but the attenuation rate of Comparative Example 3 (0.65%) is 4.3 times that of Example 4 (0.15%).

[0120] Conventional aluminum oxide deposition processes do not control the water flux and pulse time. The aluminum source flux is the same as the water flux, and the aluminum source pulse time is slightly lower than the water pulse time. The film layer has a high content of hydroxyl (-OH) and adsorbed water (H2O). Under UV irradiation, hydrogen atoms easily diffuse to the silicon interface and destroy the Si-H passivation bond. However, the present application system controls the water flux and pulse time during the deposition process to make them lower than the aluminum source flux and pulse time. The water flux is reduced by 1 sccm~10 sccm, and the water pulse time is reduced by 0.5s-4s. This reduces the hydrogen content in the aluminum oxide film layer, reduces UV-induced hydrogen secondary distribution, and thus maintains the stability of the passivation layer.

[0121] Therefore, the aluminum oxide layer with low hydrogen content is the core factor in reducing the UV attenuation rate, which maintains the stability of the passivation layer by regulating the hydrogen content.

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

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

[0124] Therefore, the introduction of the barrier layer further improves the anti-UV attenuation performance through the synergistic effect of "UV photon blocking + hydrogen diffusion inhibition", which can reduce the attenuation rate by an additional approximately 38%.

[0125] This application precisely captures the energy of absorbed UV photons by providing an anti-reflection layer containing a low-bandgap, high-refractive-index silicon nitride layer, thereby reducing UV damage to the silicon substrate interface. At the same time, a laminated aluminum oxide layer containing a low-hydrogen content aluminum oxide layer is provided to block the diffusion of active hydrogen to the silicon substrate interface. A barrier layer can also be inserted between the laminated aluminum oxide layer and the silicon nitride layer to serve as a hydrogen diffusion barrier, further maintaining the passivation stability of the cell. Furthermore, this application does not require additional annealing processes, but only adjusts the film layer. Through the synergistic effect of the film layers, the interface hydrogen concentration is reduced to suppress hot carrier damage, while light reflection loss is reduced through pre-photon absorption and refractive index matching. This ensures photoelectric conversion efficiency while improving anti-UV attenuation performance.

[0126] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A solar cell front film layer with anti-UV attenuation effect, characterized in that: The invention comprises an anti-reflection layer and a laminated aluminum oxide layer (2), wherein the anti-reflection layer is located outside the laminated aluminum oxide layer (2); the anti-reflection layer comprises a low-bandgap, high-refractive-index silicon nitride layer, 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 anti-reflection layer; the laminated aluminum oxide layer (2) comprises an aluminum oxide layer with a low hydrogen content, and the laminated aluminum oxide layer (2) is deposited by an ALD process, wherein the aluminum oxide layer with a low hydrogen content is obtained by reducing the water flux and / or the water pulse time during the deposition process.

2. The solar cell front film layer with anti-UV attenuation effect according to claim 1, characterized in that: The water flux reduction method includes: canceling the deposition process of the first layer of water in the deposition process of the laminated aluminum oxide layer (2), and / or reducing the water flux of the deposition process of any layer in the laminated aluminum oxide layer (2), and / or reducing the water flux of the deposition process of at least one layer in the laminated aluminum oxide layer (2).

3. The solar cell front film layer with anti-UV attenuation effect according to claim 2, characterized in that: The membrane layer for reducing water flux in the stacked aluminum oxide layer (2) is the aluminum oxide layer with a low hydrogen content. During the deposition process of the aluminum oxide layer with a low hydrogen content, the aluminum source flux 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.

4. The solar cell front film layer with anti-UV attenuation effect according to claim 1, characterized in that: The method of reducing the water pulse time includes: reducing the water pulse time of a deposition process of any layer in the laminated aluminum oxide layer (2), and / or reducing the water pulse time of a deposition process of at least one layer in the laminated aluminum oxide layer (2).

5. The solar cell front film layer with anti-UV attenuation effect according to claim 4, characterized in that: The film layer for reducing the water pulse time in the laminated aluminum oxide layer (2) is the aluminum oxide layer with a low hydrogen content. During the deposition process of the aluminum oxide layer with a low hydrogen content, the aluminum source pulse time is 4s to 8s and the water pulse time is 0.5s to 7.5s. Compared with the aluminum source pulse time, the reduction in the water pulse time is 0.5s to 4s.

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

1.

7. The solar cell front film layer with anti-UV attenuation effect according to claim 6, 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 one of the above, with a thickness of 1nm~10nm.

8. The solar cell front film layer with anti-UV attenuation effect according to claim 1, characterized in that: The laminated aluminum oxide layer (2) has a thickness of 2 nm to 10 nm and includes at least one aluminum oxide layer with a low hydrogen content.

9. The solar cell front film layer with anti-UV attenuation effect according to claim 1, characterized in that: The material of the anti-reflection layer is 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 band gap high refractive index silicon nitride layer is Si x N y , thickness is 5nm~30nm.

10. The solar cell front film layer with anti-UV attenuation effect according to claim 1, characterized in that: The anti-reflection 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), which are sequentially arranged from a side close to the laminated aluminum oxide layer (2) to a side away from the laminated aluminum oxide layer (2).

11. The solar cell front film layer with anti-UV attenuation effect according to claim 10, characterized in that: The first silicon nitride layer (3) is a low-bandgap, high-refractive-index silicon nitride layer, or the second silicon nitride layer (4) is a low-bandgap, high-refractive-index silicon nitride layer, or the third silicon nitride layer (5) is a low-bandgap, high-refractive-index silicon nitride layer.

12. A method for preparing a solar cell front film layer with anti-UV attenuation effect according to any one of claims 1 to 11, characterized in that: The steps include: S1: depositing a laminated aluminum oxide layer (2) on the front of the cell by an ALD process at a deposition temperature of 200°C to 350°C; S2: depositing an anti-reflection layer on the outer surface of the laminated aluminum oxide layer (2) by a PECVD process, wherein the ratio of SiH4 to NH3 inlet gas is 24% to 60% and the deposition temperature is 200°C to 600°C.

13. The preparation method according to claim 12, characterized in that The method further includes a step of depositing a barrier layer (9) between S1 and S2. The barrier layer (9) is deposited using a PECVD process. During the deposition process, the ratio of SiH4 to NH3 inlet gas is 5% to 23%, and the deposition temperature is 200° C. to 600° C.

14. A solar cell, characterized in that: A solar cell front film layer comprising the front film layer of any one of claims 1 to 11, wherein the solar cell is a TOPCon cell or a BC cell.

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