A facile solution-based aluminum oxide interface layer for enhancing the efficiency and stability of perovskite solar cells

Abstract

Hybrid organic–inorganic perovskites have emerged as very attractive light absorbers for the fabrication of low-cost and high-efficiency solar cells. However, their practical applications could be hindered due to their poor environmental stability and chemical incompatibility with charge transport layers and relevant electrodes in the devices. Herein, an ultrathin aluminum oxide (Al₂O₃) interface layer is constructed on the surfaces of perovskite films through in situ hydrolysis and condensation of aluminum triisopropoxide (ATIP) processed by a solution-processing method under ambient conditions. The Al₂O₃ layer is uniform and robust and can stabilize the perovskite film without affecting the charge transfer in the devices. Consequently, the constructed PSC exhibits a power conversion efficiency (PCE) of 23.52%, which presents the highest record reported so far for the Al₂O₃-based PSCs with the same configuration. More importantly, the Al₂O₃ incorporation leads to a significant improvement in the device stability: the PSC without encapsulation presents high operational stability with 90% of the initial efficiency after continuous maximum power point tracking over 1000 hours, and good thermal stability with 94% of the initial efficiency after aging at 60 °C in a N₂ atmosphere for 300 hours.