Tin-based perovskite solar cell
A tin-based perovskite solar cell (TPSCs) is a special type of perovskite solar cell, based on a tin perovskite structure (ASnX3, where 'A' is a monovalent organic or inorganic cation (e.g., formamidinium (FA+), methylammonium (MA+), or cesium (Cs+)), tin is in its Sn (II) oxidation state and 'X' is a monovalent halogen anion (I−, Br−, Cl−). As a technology, tin-based perovskite solar cells are still in the research phase, and are even less-studied than their counterpart, lead-based perovskite solar cells. The corresponding perovskite solar cells (PSCs) with lead have reached a certified power conversion efficiency (PCE) of 25.2%. However, the toxic lead in perovskites has caused extensive concerns regarding to the real-life applications of PSCs. 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. Therefore, the development of eco-friendly lead-free PSCs is highly desired and has emerged as a promising alternative to conventional lead-based perovskite photovoiltaicm, due to the reduced environmental impact and comparable performance potential. Several tin-based perovskites such as CsSnI3, MASnI3, and FASnI3 have been reported for fabricating lead-free PSCs. Recent studies highlight formamidinium tin iodide (FASnI3) as a leading candidate due to its superior optoelectronic properties and bandgap (~1.3 eV).
The maximum solar cell efficiency reported and certified is 16.65% for a triple-cation, double-anion (Cs,FA,PEA)Sn(I,Br)3, 14.6% for a modified formamidinium tin triiodide-based (CH(NH2)2SnI3 or FASnI3) composition with additional NH4SCN and PEABr content, 5.73% for CH3NH3SnIBr2, 3% for CsSnI3 (5.03% in quantum dots), and above 10% for various compositions based on formamidinium tin triiodide.
FASnI3 in particular may hold promise because, applied as a thin film, it appears to have the potential to exceed the Shockley–Queisser limit by allowing hot-electron capture, which could considerably raise the efficiency.