Tin as an Emerging Surrogate for Lead-free Perovskite Solar Cells

Perovskite-based photovoltaic technology has gained significant attention owing to its tunable electrical and optical properties. Among them, lead-based perovskites are considered as the most efficient one that delivers maximum power conversion efficiency with ample stability. In the current scenario, the perovskite-based solar cells (PSCs) can be classified into two main categories, i.e. highly efficient lead-containing and underperforming lead-free based. Even though lead-based PSCs delivers high efficiency, it loses the charm in the context of lead toxicity. The toxicity issue related to lead stands as a barrier to the commercialization of lead-based PSCs. To date, various materials have been prepared and implemented as an alternative to lead in the absorber layer. Tin (Sn) based perovskites are explored as an alternative absorber material owing to their photovoltaic properties that are comparable to lead. Tin-based perovskites exhibit some drawbacks, such as rapid crystallization, lack of oxidation stability, etc. Many research groups have addressed the problems regarding tin-based perovskites and modified its structural and morphological aspects through compositional engineering and functional additives and managed to obtain an efficiency of around 10%. In this review, we portray the state of the art developments of tin-based PSCs and their future perspectives.