Hydrazinium-assisted stabilisation of methylammonium tin iodide for lead-free perovskite solar cells

Abstract

Here we explore the effect of the partial substitution of univalent methylammonium (MA) cations with hydrazinium (HA) ions on the stability, morphology and photovoltaic performance of hybrid MA_(1−x)HA_xSnI₃ systems. The hydrazinium-loaded films have shown much superior stability with respect to light exposure under an inert atmosphere as compared to the reference MASnI₃ films, which undergo rapid conversion to MA₂SnI₆ under these conditions. Furthermore, the incorporation of hydrazinium ions dramatically improved the photovoltaic performance of the materials yielding a maximum efficiency of 2.6% in inverted planar junction perovskite solar cells using the optimal HA_0.2MA_0.8SnI₃ composition.