Enhanced thermoelectric efficiency of Cu2−xSe-Cu2S composite by incorporating Cu2S nanoparticles

The study of thermoelectric transport properties in Cu2−xSe and Cu2S has gained an importance in the thermoelectric research during last few years due to their superionic behavior and low cost. Here, we reported a facile method to enhance the thermoelectric efficiency of Cu2−xSe by introducing Cu2S nanoparticles (NPs) in the matrix of Cu2−xSe. The observed efficiency is a direct result of simultaneous improvement of Seebeck coefficient (S) because of the external strain induced by Cu2S nanoinclusions in Cu2−xSe and decline in the total thermal conductivity by suppressing both electronic and lattice thermal contributions. Such higher S and lower thermal conductivity is realized for a composite structure with 10 wt% nanoinclusions of Cu2S which effectively contributed to higher ZT value of 0.90 at moderate temperature of 773 K. Thus, it is believed that the proposed hybrid structure is a promising p-type thermoelectric material for mid-temperature range energy harvesting applications.