Tetramethylammonium hexafluorophosphate interface modification for high-efficiency perovskite solar cells

Abstract Interface modification has been proved to be an effective method to improve the performance of perovskite solar cells (PSCs). In this paper, tetramethylammonium hexafluorophosphate (TMAPF 6 ) is employed to modify the interface of SnO 2 /perovskite. Fluorine (F) in PF 6 − will fill the oxygen vacancy by interacting with Sn in SnO 2 . Meanwhile, TMA + and PF 6 − in TMAPF 6 will effectively fill the MA + and I − vacancy in the interface. TMAPF 6 modification enhances the hydrophobicity of the SnO 2 surface, promotes the growth of high-quality perovskite film with large grain size, and then significantly suppresses the non-radiative recombination of PSCs. Furthermore, the TMAPF 6 modification introduces a better energy level alignment between SnO 2 and perovskite layer, enabling a more efficient electron extraction. As a result, the TMAPF 6 -modified MAPbI 3 PSC achieves a significantly increasing power conversion efficiency (PCE) from 18.62% to 20.92% and an improved stability with only 15% PCE drop after 600 h of storage in air. This work develops an efficient interface modification molecule to increase the efficiency of PSCs, which would be a promising strategy for the large-scale commercialization of the photovoltaic devices.