Ga-Doping-Induced Carrier Tuning and Multiphase Engineering in n-type PbTe with Enhanced Thermoelectric Performance

摘要

P-type lead telluride (PbTe) emerged as a promising thermoelectric material for intermediate-temperature waste-heat-energy harvesting. However, n-type PbTe still confronted with a considerable challenge owing to its relatively low figure of merit ZT and conversion efficiency eta, limiting widespread thermoelectric applications. Here, we report that Ga-doping in n-type PbTe can optimize carrier concentration and thus improve the power factor. Moreover, further experimental and theoretical evidence reveals that Gadoping-induced multiphase structures with nano- to micro- meter size can simultaneously modulate phonon transport, leading to dramatic reduction of lattice thermal conductivity. As a consequence, a tremendous enhancement of ZT value at 823 K reaches similar to 1.3 for n-type Pb0.97Ga0.03Te. In particular, in a wide temperature range from 323 to 823 K, the average ZT(ave) value of similar to 0.9 and the calculated conversion efficiency eta of similar to 13% are achieved by Ga doping. The present findings demonstrate the great potential in Ga-doped PbTe thermoelectric materials through a synergetic carrier tuning and multiphase engineering strategy.