Solution-synthesized SnO2 nanorod arrays for highly stable and efficient perovskite solar cells

We report a simple and low-cost approach to enhance the longstanding stability of the perovskite solar cell (PSC) through the application of low-temperature grown SnO 2 nanorod (NR) arrays. SnO 2 NR arrays were fabricated by an aqueous synthesis method in the presence of hydrochloric acid and using thin compact SnO 2 as seeds. The influence of HCl concentration on the photovoltaic (PV) performance of the SnO 2 NR array based PSC device was investigated. The formed crystalline SnO 2 nanorods with square transversal-sections were oriented on the FTO facets in a well-defined and perpendicular fashion at an optimal HCl concentration. The optimized width and length for SnO 2 nanorods were 30 nm and 150 nm, respectively. Consequently, efficient and stable SnO 2 nanorod based perovskite devices were obtained with an average power conversion efficiency (PCE) of 16.57%. The SnO 2 nanorod array based PSCs demonstrated considerably better ultraviolet (UV) and ambient air stability than the planar SnO 2 and notably mesoporous TiO 2 solar cells. This paper provides a prospective scheme to grow high-quality three-dimensional SnO 2 nanorod arrays for highly stable and efficient PSCs.