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.