Improvement of nano-texture uniformity formed on crystalline silicon surface by anisotropic alkaline etching for perovskite/silicon tandem solar cells

Abstract

Perovskite/silicon tandem solar cells have attracted attention as a promising approach to exceed the efficiency limit of single-junction silicon solar cells. To improve efficiency, submicron-sized textures on the silicon surface are effective. In this study, a silver-free alkaline etching process was developed to form submicron textures for superior light management and conformal liquid phase deposition of the perovskite thin films. The effects of additive concentrations and etching durations on texture formation in alkaline etching using additives were investigated. In addition, the roles of additives and surfactants in comparison with isopropyl alcohol-added etching were discussed. As a result, submicron textures with an average height of 572 nm were successfully formed. Optical characterization revealed that the textures suppress reflectance to approximately 15%, which is comparable to that of conventional textures.