Abstract:
Tin (Sn) is a potential replacement for lead in organic–inorganic perovskite solar cell (PVSC) technology due to the attractive optoelectronic properties of Sn-perovskites. However, the poor stability of Sn2+ ions is still the main hindrance for achieving highly stable and efficient Sn-based PVSCs. In this work, anilinium hypophosphite (AHP) is introduced as a co-additive into a Sn-absorber perovskite precursor containing the tin fluoride (SnF2) additive. The incorporation of the AHP additive not only prohibits the phase separation of SnF2 but also passivates the perovskite films and finally results in absorbers with superior structural and optoelectronic properties. The underlying reason is related to the formation of a double-salt complex (Sn(H2PO2)2·SnF2) through the interaction between AHP and SnF2. The high quality of the absorber film induced by AHP delivers an improved device power conversion efficiency (PCE) with a higher open-circuit voltage than those without the AHP additive. More importantly, the device with the AHP additive can retain up to 97% of its PCE after 30 days of storage in a glovebox.