In-situ formed and low-temperature deposited Nb: TiO2 compact-mesoporous layer for hysteresis-less perovskite solar cells with high performance
Abstract Recently, reported perovskite solar cells (PSCs) with high power conversion efficiency (PCE) are mostly based on mesoporous structures containing mesoporous titanium oxide (TiO 2 ) which is the main factor to reduce the overall hysteresis. However, existing fabrication approaches for mesoporous TiO 2 generally require a high temperature (>450 °C) annealing process. Moreover, there is still plenty of scope for improvement in terms of increasing the electron conductivity and reducing the carrier recombination. Herein, a facile one-step, in situ and low-temperature method was developed to prepare an Nb:TiO 2 compact-mesoporous layer to serve as both a scaffold and an electron transport layer (ETL) in PSCs. The Nb:TiO 2 compact-mesoporous layer based PSCs exhibit suppressed hysteresis, which is attributed to the synergistic effect of the large interface surface area caused by nano-pin morphology on the surface and the improved carrier transportation caused by the presence of Nb. Such a high-quality compact-mesoporous layer allows the PSC achieve a remarkable PCE of 19.74%. This work promises an effective approach for creating hysteresis-less and high-efficiency PSCs based on compact-mesoporous structures with lower energy consumption and cost.