Yb-doped SnO electron transfer layer assisting the fabrication of high-efficiency and stable perovskite solar cells in air.

To date, most preparation processes of polycrystalline perovskite films still have to be performed in a glovebox filled with inert gas, limiting the application due to their high cost and complexity. In this work, we exploit a facile processing technique for the preparation of perovskite solar cells (PSCs) under ambient conditions by the Yb doping effect for SnO electron transfer layer. This remarkable and facile interface doping strategy promotes all-air processed planar PSCs, giving enhanced power conversion efficiency (PCE) from 15.69% to 17.31% with a decreasing hysteresis effect. Moreover, the heating and illumination stability of modified devices by virtue of defect suppression located at electron transfer layer (ETL)/perovskite interface has been effectively improved, retaining over 85% of its initial PCE after 7 h heating at 100 °C in ambient condition and 85% of its initial PCE under 7 h continuous light illumination without any encapsulation. Therefore, it is believed that this Yb-doping strategy for SnO ETL can provide a novel way of promoting the efficiency and stability of devices prepared in the air.