Prospective and challenges for lead-free pure inorganic perovskite semiconductor materials in photovoltaic application: A comprehensive review

The next-generation solar cells are metal halide-based hybrid perovskite solar cells (PSCs), and we have already passed the point where three generations of solar cells were developed. PSCs is one of the younger class of photovoltaic devices among others and have provided a steep change in photovoltaic research ever the date which has experienced an extraordinary increase in efficiency along with its stability and have appeared as an extremely efficient photovoltaic technology. The biggest problems with this material are keeping it from degrading in wet environments and keeping it from overheating. Besides this, the second concerned issue is the toxicity of lead (Pb), which could be an encumbrance for large-scale production due to environmental concerns. Consequently, significant effort has been devoted to finding alternative halide perovskites with excellent optoelectronics applications, consisting of completely inorganic components of low-cost, less toxic elements. The use of environmentally friendly materials in all-inorganic lead-free perovskites aims to alleviate these problems. Aside from that, there is a diverse spectrum of inorganic materials that can form perovskite structures, providing material flexibility for specific applications. This review paper provides a comprehensive overview of the literature on Pb-free perovskite materials, discussing their design methods, morphologies, and environmental stability problems. First, a comparison is made between the elements of Tin (Sn) and Pb, and some Pb is replaced with Sn. The fact that Germanium (Ge), transition metals, and elements from other columns of the periodic table can replace this element is emphasized. We conclude our study with a critical assessment of the current issues and potential future directions for this rapidly developing discipline.