UV-OZONE Treatment\nfor Suppressing Surface Damages\non Silicon Solar Cells

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