Metal-Assisted Chemical Etching for Solar Cell Texturing

A method for creating a photovoltaic wafer surface with a controlled porosity layer that significantly reduces light reflection. The method involves applying a solution of a linear or branched-chain alcohol with 10 carbon atoms or less to the wafer surface, followed by treatment with metal ion-containing hydrofluoric acid. The alcohol treatment creates a uniform, controlled porosity structure on the wafer surface, while the hydrofluoric acid treatment selectively removes metal ions to create micropores. The resulting wafer surface exhibits significantly reduced light reflection compared to standard silicon surfaces, achieving an optimized photovoltaic performance.

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A method for texturing silicon wafers using room-temperature copper-assisted etching that enables high-efficiency solar cells. The method employs copper nanoparticles to create pyramid-like structures on the silicon surface during etching, where the copper nanoparticles nucleate and grow in response to the etching environment. This spontaneous growth process enables the formation of pyramid structures with controlled dimensions and orientations, significantly reducing surface reflectance compared to traditional etching methods. The method achieves an average reflectance of less than 11% across the solar spectrum, enabling efficient solar cell performance.

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Etching method for TOPCon solar cells that reduces cost, chemical consumption, and over-etching risk compared to conventional methods. The method involves sequential acid and alkali etching steps to remove layers from the TOPCon cell. First, an acid etch removes the PSG layer on the front side. Then, an alkali etch removes the exposed polysilicon. Finally, an acid etch removes the BSG on the front side and the remaining PSG on the back side. This step-by-step approach avoids using nitric acid and sodium hydroxide together, which can lead to over-etching and waste.

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Solar cell unit with enhanced power generation efficiency through controlled patterning of metal and insulating layers. The solar cell comprises a semiconductor substrate with a metal layer, an insulating layer, and a second semiconductor layer. A resist layer containing resin and inorganic particles is applied to the metal layer and insulating layer, with the resist layer forming conical-shaped openings that penetrate these layers. The resist layer's conical shape is optimized to ensure precise patterning while maintaining structural integrity. This controlled patterning enables precise control over the metal and insulating layer interfaces, resulting in improved electrical isolation and reduced defects in the solar cell.

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A metal ion-assisted non-nitric acid polishing method for high-efficiency solar cells. The method improves the reflective surface of PERC solar cells by enhancing the uniformity of the back passivation coating. The polishing process involves cleaning the polished silicon wafer, followed by a metal ion-assisted etching step that selectively removes defects and impurities while maintaining the metal ion concentration. This approach enables improved reflectivity and stability compared to conventional acid-based polishing methods, while minimizing the environmental impact of acid waste disposal.

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Manufacturing method for silicon substrates for solar cells that enables high-efficiency heterojunction solar cells through improved substrate surface preparation. The method involves a three-step etching sequence: first, a standard etching process removes surface damage and contaminants from the silicon substrate; second, a specialized etching step with an alkali and additive for anisotropic etching creates a textured surface; and third, a standard cleaning step removes any remaining etching residues. This approach enables precise control over substrate surface preparation, including texture formation and defect reduction, which are critical for achieving high-efficiency solar cell performance.

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A method for enhancing the surface texturing of silicon wafers for solar cells through controlled etching. The process employs a gas mixture containing fluorine (F2) and hydrogen fluoride (HF) with varying concentrations, specifically 0.1-20 vol%, 2.5-1.000 ppmv HF, and balance of inert gases. The controlled etching conditions, including temperature and pressure, enable precise control over etch rate, depth, and pattern formation, while maintaining surface quality.

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Surface pretreatment for crystalline silicon RIE textured solar cells to enhance light confinement through controlled nano- to micron-scale texture formation. The pretreatment process involves a controlled etching step that suppresses the formation of pyramidal structures while maintaining a flat surface. This step enables the formation of nano-scale texture structures without the limitations of traditional wet chemical etching methods, which can create pyramidal structures that significantly reduce light absorption. The surface pretreatment enables further optimization of solar cell performance through improved light trapping and reduced reflectivity.

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A method for selective back etching of highly doped silicon layers in solar cell emitters, enabling uniform reverse etching through controlled oxidation and selective metal deposition. The process employs a low-temperature hypochlorite solution to selectively etch the emitter surface while preventing anisotropic etching, thereby maintaining uniform thickness. The selective etching is achieved through precise control of the hypochlorite concentration and temperature, allowing for precise control of the oxide layer thickness. The selective metal deposition step enables the deposition of selective metal layers on the back-etched surface, providing a uniform and selective surface finish for solar cell fabrication.

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Manufacturing a solar cell with enhanced texture structure formation on the silicon substrate surface. The process involves sequential etching steps with different etching solutions, where the initial etching solution has a lower etching rate and the subsequent solution has a higher etching concentration. This sequential etching approach creates a textured surface on the silicon substrate, enabling improved solar cell performance characteristics.

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Method for manufacturing high-efficiency silicon solar cells through controlled nanowire formation. The method involves electrochemically etching a metal catalyst layer on a silicon substrate to create nanowire structures, followed by controlled etching of the catalyst layer using a specific etching solution. This approach enables precise control over the nanowire morphology while maintaining high efficiency.

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Silicon solar cells with enhanced electrical properties for thin emitter layers. The cells feature a silicon layer with an intentionally porous emitter region where metal silicide is deposited, followed by a metal contact layer. This design enables superior electrical contact resistance and conductivity between the metal contacts and the silicon base, while maintaining high bonding strength. The porous emitter region in the emitter layer is specifically created through chemical or electrochemical etching, with the metal contacts applied directly to the silicide surface. This configuration enables reliable operation at very thin emitter layer thicknesses without electrical shorts.

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Locally contacting semiconductor elements in photovoltaic solar cells by forming metal structures through selective removal of the semiconductor material. The method involves creating metal contacts through selective removal of the semiconductor material, allowing precise control over the contact geometry and avoiding thermal damage. The metal structure is then formed by selectively removing the semiconductor material in the contact area, enabling the creation of precise contact patterns while maintaining electrical integrity.

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A method for creating high-quality solar cells with improved surface properties through a single-step process. The method involves etching a silicon wafer surface with an acidic etchant, followed by a passivation layer deposition. The acidic etchant selectively removes contaminants while preserving the underlying wafer surface, enabling a single-step process that eliminates the need for additional cleaning steps. The passivation layer is then applied to the wafer surface, followed by laser patterning for local contact structures. This approach preserves the wafer's native surface characteristics while achieving the desired surface texture and passivation properties.

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