Selective Control of Novel TiO Nanorods: Excellent Building Blocks for the Electron Transport Layer of Mesoscopic Perovskite Solar Cells.

Novel TiO nanorods (NRs) with various lengths of 70-200 nm and uniform widths of 46-48 nm are selectively synthesized by a solvothermal reaction under a basic environment. The length of TiO NRs is reproducibly tuned by varying the concentration of tetramethylammonium hydroxide (TMAH), while the NRs in the pure anatase phase are grown in the [001] direction, caused by the preferential binding affinity of TMAH to the TiO (101) facet. TiO NRs of various lengths are then applied to form the electron transporting layer (ETL) of mesoscopic perovskite solar cells (PSCs).