Recent progress, fabrication challenges and stability issues of lead-free tin-based perovskite thin films in the field of photovoltaics

Lead-halide perovskite materials have fascinated incredible attention among the research communities due to their favorable electrical and optical properties for optoelectronics and photovoltaic application such as significant light absorption coefficient, higher values of diffusion length, carrier mobility, carrier lifetime, etc. However, lead toxicity as well as its low material stability makes it still far from commercialization. Finding of lead ion replacement is therefore needed to form environmental friendly perovskite materials that are called lead-free perovskites. Among different substitutions, tin is the most potential candidate that is also non-toxic. In this review, the recent development of tin-based lead-free perovskite thin films in photovoltaics research area during the period 2014 till now is summarized. Moreover, the technical challenges and the stability issues faced by them are also discussed. Further, it is suggested that more efforts are needed for the advancement of tin-based lead-free perovskite thin films based solar cells to bring up this field as a cost competent technology for long term sustainability.