Investigation of thermoelectric properties of Cu₂SnSe₃ composites incorporated with SnSe

Cu₂SnSe₃ has been considered as a potential thermoelectric material owing to its cost-effective and nontoxic constituent elements along with its high electrical conductivity. However, its low Seebeck coefficient has been a concern towards realizing a high figure-of-merit. In the present study, Cu₂SnSe₃/xSnSe (x = 0, 5, 10, and 20 wt %) composite samples whose thermoelectric performance has been studied in the temperature range 10–375 K, shows that the Seebeck coefficient of sample containing 10% SnSe is ~3.6 times that of the pure. The incorporation of SnSe has resulted in a significant increase in electrical resistivity and Seebeck coefficient which is attributable to the decrease in carrier concentration with increase in SnSe content. Concurrently, a power factor (PF) of 35.60 μW/mK² has been attained for x = 10% sample at 375 K. However, due to the increase in thermal conductivity with the addition of SnSe, the composites have lower ZT values than that of the pristine Cu₂SnSe₃ sample. Furthermore, the Vicker's microhardness, which is a key measure for the mechanical strength of a material, has distinctly improved by the addition of SnSe.