Optoelectronic property refinement of FASnI3 films for photovoltaic application.

[Display omitted] • Anilinium hypophosphite was used as a co-additive in FASnI 3 perovskite. • Anilinium hypophosphite improved the perovskite optoelectronic properties. • Enhanced photovoltaic performance was obtained using new additive. Tin (Sn) is a promising substitute for lead (Pb) in organic–inorganic hybrid halide perovskite-photovoltaic devices, but it is prone to delivering low power conversion efficiencies (PCEs) due to the poor quality of Sn-perovskite films. In this work, anilinium hypophosphite (AHP) co-additive is used to fabricate high-quality FASnI 3 (FA+: formamidinium) perovskite films with suppressed phase-segregation and prolonged charge carrier lifetime. Perovskite films containing 0.05 M AHP are used to fabricate solar cells and deliver improved power conversion efficiency (PCE) of up to 5.48% (control devices: 4.04%). AHP eliminates the phase separation caused by SnF 2 in the absorber, leading to films with enhanced optoelectronic properties, hence the high performance of AHP-based devices. [ABSTRACT FROM AUTHOR]