High-Performance and Hysteresis-Free Perovskite Solar Cells Based on Rare-Earth-Doped SnO 2 Mesoporous Scaffold

Tin oxide (SnO 2 ), as electron transport material to substitute titanium oxide (TiO 2 ) in perovskite solar cells (PSCs), has aroused wide interests. However, the performance of the PSCs based on SnO 2 is still hard to compete with the TiO 2 -based devices. Herein, a novel strategy is designed to enhance the photovoltaic performance and long-term stability of PSCs by integrating rare-earth ions Ln 3+ (Sc 3+ , Y 3+ , La 3+ ) with SnO 2 nanospheres as mesoporous scaffold. The doping of Ln promotes the formation of dense and large-sized perovskite crystals, which facilitate interfacial contact of electron transport layer/perovskite layer and improve charge transport dynamics. Ln dopant optimizes the energy level of perovskite layer, reduces the charge transport resistance, and mitigates the trap state density. As a result, the optimized mesoporous PSC achieves a champion power conversion efficiency (PCE) of 20.63% without hysteresis, while the undoped PSC obtains an efficiency of 19.01%. The investigation demonstrates that the rare-earth doping is low-cost and effective method to improve the photovoltaic performance of SnO 2 -based PSCs.