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.