Thermoelectric Properties of Cu 2 Te Nanoparticle Incorporated N-Type Bi 2 Te 2.7 Se 0.3 .

To develop highly efficient thermoelectric materials, the generation of homogeneous heterostructures in a matrix is considered to mitigate the interdependency of the thermoelectric compartments. In this study, Cu 2 Te nanoparticles were introduced onto Bi 2 Te 2.7 Se 0.3 n-type materials and their thermoelectric properties were investigated in terms of the amount of Cu 2 Te nanoparticles. A homogeneous dispersion of Cu 2 Te nanoparticles was obtained up to 0.4 wt.% Cu 2 Te, whereas the Cu 2 Te nanoparticles tended to agglomerate with each other at greater than 0.6 wt.% Cu 2 Te. The highest power factor was obtained under the optimal dispersion conditions (0.4 wt.% Cu 2 Te incorporation), which was considered to originate from the potential barrier on the interface between Cu 2 Te and Bi 2 Te 2.7 Se 0.3 . The Cu 2 Te incorporation also reduced the lattice thermal conductivity, and the dimensionless figure of merit ZT was increased to 0.75 at 374 K for 0.4 wt.% Cu 2 Te incorporation compared with that of 0.65 at 425 K for pristine Bi 2 Te 2.7 Se 0.3 . This approach could also be an effective means of controlling the temperature dependence of ZT , which could be modulated against target applications.