Enhanced performance of TiO2-based perovskite solar cells with Ru-doped TiO2 electron transport layer

Perovskite solar cells (PSCs) as the most promising alternative to the Si solar cells have been developed rapidly in recent time. Superior electron mobility and conductivity of the compact layer material are necessary for high efficiency in perovskite solar cells by reducing excessive charge accumulation and guaranteeing effective electron injection at the compact layer/perovskite interface. In this study, Ru ions were introduced into traditional compact TiO 2 to improve the electron transporting layer (ETL) properties and conductivity performance. Ru 4+ was discovered in the Ru:TiO 2 according to the result of XPS. The reduced trap-filled limit voltage (V TFL ) of the Ru:TiO 2 compact layers showed that trap density in the Ru:TiO 2 film was lower than that of the pristine TiO 2 film. The PSCs based on 1 mol% Ru:TiO 2 exhibited the suitable band gap, low resistivity and high carrier density, comparing with the undoped compact TiO 2 , the charge transportation at the compact layer/mesoporous layer interface was enhanced with the incorporation of Ru, resulting in the reduction in hysteresis of the device. The power conversion efficiency (PCE) of the Ru-doped compact TiO 2 film based PSCs was improved from 14.83% to 18.35%.