Exploring the potential of Cu₂FeSnS₄: a comprehensive review on structural properties, optoelectronic features, and future prospects in earth-abundant thin film solar cells

Cu-based earth-abundant ternary and quaternary chalcogenides are gaining intense interest in environmentally benign thin film solar cells. Recently, Cu₂FeSnS₄ (CFTS), has pulled prime attention in research and development due to their exceptional optoelectronic properties in addition to the nontoxic nature and composition consisting of earth abundant constituent elements. CFTS has a high optical absorption coefficient (>10⁴ cm⁻¹) and a suitable bandgap range (1.2-1.5 eV) to be used as an absorber layer in thin film solar cells. Despite several preliminary works in the recent past, the potential of CFTS in solar cell applications has not yet been systematically explored. This mini review article begins with a brief insight into the importance and background of this potential material. Various synthesis methods employed for the deposition, characteristics of such deposition along with a few important results obtained are presented. Moreover, recent advancements in the CFTS thin film based photovoltaic device performance studies, challenges, strategies to realize for such device applications and outlook for further developments are discussed. Additionally, this review gives a comprehensive insight into the various possible defects and their impact on the performance and feasible solutions to mitigate these issues to enhance the optoelectronic properties of CFTS thin films.