Enhancing Performance of Perovskite Solar Cells by TiCl₄ Treatment on the Surface Roughness of the Titanium Dioxide Layer.

Perovskite solar cells have been attracting extensive attention because of their superior photovoltaic performances and lower costs as compared to those of prevailing photovoltaic technologies. There are four main interfaces in perovskite solar cells: flourine-doped tin oxide/electron transport layer, electron transport layer/perovskite layer, perovskite layer/hole transport layer, and hole transport layer/metal electrode. Among them, the interface between the perovskite layer (general formula RPbX₃) and electron transport layer significantly affects the power conversion efficiency. In this study, a layer of TiO₂, which is the most popular metal oxides used for perovskite solar cells applications, was deposited as the electron transport layer. To enhance the perovskite solar cells performance, surface treatment was performed with TiCl₄ (80 mM). To investigate the effect of TiCl₄ treatment, ultraviolet-visible spectroscopy was performed on the perovskite film. Atomic force microscopy, X-ray diffraction, scanning electron microscopy and performance of perovskite solar cells have been also evaluated in this paper. The results indicated that the TiCl₄ treatment significantly improved the perovskite solar cells performance.