Cu2SnS3

Cu2SnS3 is a copper tin sulfide compound studied as a thin-film semiconductor. Comprised of copper, tin, and sulfur in a simple ternary composition, it belongs to the broader family of copper chalcogenides that have attracted attention for photovoltaic and optoelectronic applications due to the earth-abundant elements involved and relatively low toxicity compared with some alternative solar absorbers.

The material can crystallize in multiple structural forms, and the exact phase is sensitive to synthesis conditions such as temperature and composition. This polymorphism, along with potential off-stoichiometry, leads to a variety of defect chemistries. Common defects include copper vacancies and tin-related defects, which tend to promote p-type conductivity. The electronic properties, including the bandgap, are reported to be tunable by phase and composition, with values often described as lying in the visible to near-infrared range. A high optical absorption coefficient is typical, supporting potential use as a light absorber in thin-film devices.

Synthesis routes for Cu2SnS3 are diverse and include solid-state reactions, high-temperature crystallization, and various thin-film deposition techniques such as sputtering, evaporation, and solution-based routes. Processing challenges include phase stability and controlling secondary phases, as well as defect-related recombination centers that can limit device performance.

Applications and research status: Cu2SnS3 is primarily explored as a potential absorber layer for photovoltaic cells and related optoelectronic devices. While it offers the advantage of earth-abundant, non-toxic constituents, practical devices face hurdles related to phase control, defect management, and achieving high efficiency. Ongoing studies aim to optimize synthesis, defect chemistry, and alloying strategies to improve performance.