Preparation method of crystalline silicon solar cell textured structure

Abstract

The invention discloses a method for preparing a textured surface structure of a crystalline silicon solar cell, which comprises the following steps: (1) forming a porous layer structure on the surface of a silicon chip; (2) etching the surface with a first chemical etching solution to form the textured surface surface structure; the first chemical etching solution is a mixed solution of hydrofluoric acid, an oxidizing agent and an additive; the additive is acetic acid or citric acid. The present invention designs a new chemical etching solution, and uses the chemical etching solution to etch the surface of the porous layer structure to form a suede structure. The experiment proves that the reaction speed of the chemical etching solution of the present invention is controllable, so that the suede surface can be guaranteed. The stability and uniformity of the structure, and the stability of the electrical performance of the solar cell.

Description

technical field [0001] The invention relates to a method for preparing a textured surface structure of a crystalline silicon solar cell, belonging to the technical field of solar cells. Background technique [0002] With the wide application of solar cell components, photovoltaic power generation occupies an increasingly important proportion in new energy and has achieved rapid development. Among the currently commercialized solar cell products, crystalline silicon (monocrystalline and polycrystalline) solar cells have the largest market share, maintaining a market share of more than 85%. [0003] At present, in the production process of solar cells, the textured structure on the surface of silicon wafers can effectively reduce the surface reflectance of solar cells, which is one of the important factors affecting the photoelectric conversion efficiency of solar cells. In order to obtain a good textured structure on the surface of crystalline silicon solar cells to achieve ...

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Problems solved by technology

Invention patent application WO2014120830 (A1) discloses a method for preparing crystalline silicon nano-texture, which controls the shape of nano-texture by annealing, but the method is complicated and not conducive to the needs of industrial production

[0006] However, it has been found in practical applications that the above-mentioned method has the following problems: (1) the first chemical etching solution in the step (2) of the above-mentioned method mainly has two functions, one is to etch the porous silicon layer formed by metal catalysis; The second is to clean the residual metal particles on the surface of the silicon wafer; yet, as the number of silicon wafers increases, the first chemical etching solution (i.e. HF / HNO) in step (2) 3 The Ag ions in the mixed solution) are more and more, and become HF / HNO rich in Ag ions 3 Mixed solution, and the silicon chip will again undergo metal ion catalyzed chemical etching reaction in this solution, which will affect the stability and uniformity of the textured structure, thereby affecting the electrical performance of the solar cell; (2) with the increase in the number of processed silicon chips increase, the Ag ions in the first chemical etching solution in the step (2) of the above-mentioned method are more and more, and the Ag ions will be attached to the silicon wafer again in reverse, and it is difficult to remove the Ag ion attached to the silicon wafer in the first process. Particles are washed clean, resulting in HF / HNO 3 The life-span of mixed solution is very short, thereby further increased cost; (3) because the existing first chemical etching liquid such as HF / HNO 3 The reaction speed of the system is fast and the heat release is large, which will cause the problems of chromatic aberration and uneven microstructure of different crystal planes; especially for polycrystalline silicon wafers, since polycrystalline silicon wafers are composed of crystal flowers with different crystal orientations, and the crystal flowers of each crystal flower Randomly distributed, and crystal flowers are obvious, so it is more likely to have problems such as large suede size and poor uniformity, obvious crystal flowers, slightly high reflectivity, and poor texture stability.

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