Vertically aligned nanostructured TiO2 photoelectrodes for high efficiency perovskite solar cells via a block copolymer template approach

Abstract

We fabricated perovskite solar cells with enhanced device efficiency based on vertically oriented TiO₂ nanostructures using a nanoporous template of block copolymers (BCPs). The dimension and shape controllability of the nanopores of the BCP template allowed for the construction of one-dimensional (1-D) TiO₂ nanorods and two-dimensional (2-D) TiO₂ nanowalls. The TiO₂ nanorod-based perovskite solar cells showed a more efficient charge separation and a lower charge recombination, leading to better performance compared to TiO₂ nanowall-based solar cells. The best solar cells employing 1-D TiO₂ nanorods showed an efficiency of 15.5% with V_OC = 1.02 V, J_SC = 20.0 mA cm⁻² and fill factor = 76.1%. Thus, TiO₂ nanostructures fabricated from BCP nanotemplates could be applied to the preparation of electron transport layers for improving the efficiency of perovskite solar cells.