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A tin-based perovskite solar cell is a special type of perovskite solar cell, where the lead is substituted by tin. It has a tin-based perovskite structure , where 'A' is a 1+ cation and 'X' is a monovalent halogen anion. The methylammonium tin triiodide has a band gap of 1.2–1.3 eV, while formamidinium tin triiodide has a band gap of 1.4 eV.
Tin-based perovskite solar cells are still in the research phase and there are relatively few publications about them, compared to their counterpart, lead-based perovskite solar cells. This is mainly due to the instability of the 2+ oxidation state of tin in methylammonium tin iodide , which can be easily oxidized to the more stable Sn, leading to a process called self doping, where the Sn acts as a p-dopant leading to the reduction in the solar cell efficiency.
The maximum solar cell efficiency reported is 6.4% for methylammonium tin iodide , 5.73% for CH3NH3SnIBr2, 2.02% for CsSnI3. and above 9% for formamidinium tin triiodide 2SnI3].
The main advantages of tin-based perovskite solar cells are that they are lead-free and that can help to further tune the band-gap of the active layer. There are environmental concerns with using lead-based perovskite solar cells in large-scale applications; one such concern is that since the material is soluble in water, and lead is highly toxic, any contamination from damaged solar cells could cause major health and environmental problems.