Photovoltaics based on tin halide perovskites have not yet benefited from the same intensive research effort that has propelled lead perovskite photovoltaics to >20% power conversion efficiency, due to the susceptibility of tin perovskites to oxidation, the low energy of defect formation and the difficultly in forming pinhole-free films. Here we report CsSnI₃ perovskite photovoltaic devices without a hole-selective interfacial layer that exhibit a stability …10 times greater than devices with the same architecture using methylammonium lead iodide perovskite, and the highest efficiency to date for a CsSnI₃ photovoltaic: 3.56%. The latter largely results from a high device fill factor, achieved using a strategy that removes the need for an electron-blocking layer or an additional processing step to minimize the pinhole density in the perovskite film, based on co-depositing the perovskite precursors with SnCl₂. These two findings raise the prospect that this class of lead-free perovskite photovoltaic may yet prove viable for applications.

Nature Energy 1, Article number: 16178 (2016)
doi:10.1038/nenergy.2016.178

http://www.nature.com/articles/nenergy2016178