Band alignment of TiO2 by controling Cl content for high-efficiency perovskite solar cells

Abstract

Titanium oxide (TiO₂) layers are widely used in perovskite electron transport. Owing to its excellent electron transport capability, solar cell devices containing a TiO₂ layer achieve high conversion efficiency. However, the realization of highly-efficient devices on unmodified flat TiO₂ is still a tricky problem. Therefore, this work changed the method of preparing TiO₂ in an aqueous solution and prepared a type of TiO₂ film with high Cl content on the surface and a low interface defect in contact with perovskite. It was found that this novel method achieved the highest conversion efficiency of 24.31%. This work provides a new idea for the preparation of a low-defect TiO₂ electron transport layer.