Fabrication method of black silicon solar cell

Abstract

The invention discloses a fabrication method of a black silicon solar cell. The fabrication method comprises the following steps of (1) polishing the surface of a silicon wafer to be processed; (2) forming a doping junction on a polished surface of the silicon wafer; (3) back-etching by an HF solution, and forming a black silicon structure as well as removing a dead layer on the surface of the silicon wafer; and (4) carrying out cleaning, etching, edge removal, anti-reflection film plating, screen printing and sintering to form ohmic contact, thereby obtaining the black silicon solar cell. According to the fabrication method, the black silicon structure is formed as well as the dead layer on the surface of the silicon wafer is removed, the surface recombination is reduced, and moreover, the conversion efficiency of the solar cell is effectively improved.

Description

technical field [0001] The invention relates to a method for preparing a black silicon solar cell, belonging to the technical field of solar cells. Background technique [0002] Conventional fossil fuels are increasingly depleted. Among all sustainable energy sources, solar energy is undoubtedly the cleanest, most common and most potential alternative energy source. At present, among all solar cells, crystalline silicon solar cells are one of the solar cells that have been widely commercialized. This is due to the extremely abundant reserves of silicon materials in the earth's crust. Cells have excellent electrical and mechanical properties, therefore, crystalline silicon solar cells occupy an important position in the field of photovoltaics. [0003] On the other hand, black silicon (black silicon) is a new type of electronic material discovered by the latest research that can greatly improve the photoelectric conversion efficiency. Black silicon material is a layer of na...

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Problems solved by technology

There are a large number of interstitial atoms, dislocations and defects in the diffusion dead layer, and the minority carrier lifetime is low. The photogenerated carriers emitted by sunlight in the dead layer are all recombined, resulting in a decrease in the conversion efficiency of the cell.

[0005] At present, there are basically three methods for removing the diffusion dead layer: (1) Shallow junction: generally make the emitter junction shallower, 0.1 micron can avoid this phenomenon; the existing black silicon solar cell manufacturing process is to use this However, this greatly increases the difficulty of the preparation process, and this will increase the series resistance, because the existence of the dead layer cannot be avoided, and the generation of the dead layer can only be reduced by a certain process; (2) through oxidation Layer P diffusion: first form an oxide layer, and then carry out P diffusion; but the effect of this method to remove the dead layer is not ideal; (3) back engraving after diffusion: use a corrosive chemical solution to perform back engraving to remove the dead layer; in the prior art , in order to increase the corrosion rate, HF and HNO are generally used 3 However, it has been found in practical applications that the corrosion process is difficult to control, the corrosion uniformity is poor, and the cost is high, so it has not been able to be used in large quantities.

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