UV-OZONE Treatment for Suppressing Surface Damages on Silicon Solar Cells

In the preparation process of c-Si solar cells, qualified Si wafers must be processed through mechanical processing during manufacturing. Most of these processes involve mechanical processing, which inevitably results in severe mechanical damage layers and a wafer surface with large roughness. The current industry practice involves etching of the damage layer using an acid/alkali solution, and it is usually followed by deposition of additional passivation layers in the subsequent processes. However, even with these treatments, there still remain non-negligible microscopic saw damage and scratches on the wafer surface, which hinder the urgent development of a higher conversion efficiency of solar cells. Here, we provide a simple method to effectively suppress the impact of this surface damage. UV-OZONE treatment, which involves generation of an oxide layer and subsequent cleaning with hydrofluoric acid, leads to the effective regain of solar cell performance due to the passivation of dangling bonds and removal of sharp microstructures based on the creation of mechanical scratches. In addition, PEDOT:PSS/n-Si solar cells were prepared to exploit their strong surface dependence to investigate the effect of scratches on the overall performance. These results further validate the impact of scratches on solar cells, and a simple and effective method for surface damage suppression is provided.