Improving thermoelectric performance of p-type PbSe via synergistically enhancing Seebeck coefficient and reducing electronic thermal conductivity
In this work, the thermoelectric performance of p-type PbSe was improved dramatically by enhancing Seebeck coefficient and reducing electronic thermal conductivity through alloying CdTe. CdTe alloying effectively increased the effective mass of p-type Pb0.98Na0.02Se due to band flattening and promoting the valence band convergence, which contributed to a high Seebeck coefficient of ~ 238 μV K-1 at 860 K and large power factor of ~ 18.2 μW cm-1 K-2 at 860 K for Pb0.98Na0.02Se+4%CdTe. Furthermore, CdTe alloying reduced the carrier mobility of Pb0.98Na0.02Se due to the enhanced scattering of impurity atoms, which results in a remarkable reduction of electronic thermal conductivity. As a result, due to higher power factor and lower thermal conductivity, a high thermoelectric figure of merit ZT ~ 1.5 at 860 K was achieved in Pb0.98Na0.02Se+4%CdTe. This paper provides one novel approach to enhance thermoelectric performance of p-type PbSe through synergistically manipulating electrical and thermal transport properties.