In dopant enabled resonant level for thermoelectric enhancements in PbSnGeTe3

Abstract

Resonant level engineering is an effective strategy to increase the Seebeck coefficient of thermoelectric semiconductors for high performance. Herein, we report a significant enhancement of the thermoelectric performance of PbSnGeTe3 over a wide temperature region through the In doping induced resonant level. Due to the simultaneously strengthened effective mass by inducing resonant levels nearby the Fermi level and decreased carrier concentration, a considerably improved Seebeck coefficient is obtained in In-doped PbSnGeTe3 and thereby the greatly increased power factor. The decreased carrier concentrations resulting from In substitution can also suppress the electronic thermal conductivity for a decreased thermal conductivity. The enhanced power factor and reduced thermal conductivity finally contribute to an extraordinarily high average ZT of 0.93 between 300 and 773 K in PbSnGeTe3. These observations demonstrate the viability of resonant levels in advancing thermoelectric materials with intrinsically high carrier concentrations.