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

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 x SnI 3 systems. The hydrazinium-loaded films have shown much superior stability with respect to light exposure under an inert atmosphere as compared to the reference MASnI 3 films, which undergo rapid conversion to MA 2 SnI 6 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 0.2 MA 0.8 SnI 3 composition.