Realizing high thermoelectric performance in PbSe crystal via zinc doping and indium interstitial doping

The scarcity of tellurium poses a challenge to the widespread application of Bi₂Te₃-based thermoelectric devices. In this study, the temperature gradient method for crystal growth and two-step trace, interstitial doping were employed to enhance the power factor of Te-free PbSe, thereby exploring its potential in thermoelectric applications. Firstly, a trace amount of Zn was introduced into the interstitial sites of PbSe to obtain N-type PbSe crystals and optimize the carrier concentration. Subsequently, trace doping of In was performed: the In atoms act not only as cationic dopants to substitute Pb but also occupy interstitial sites, simultaneously increasing the carrier concentration and reducing the lattice thermal conductivity. Ultimately, the resulting material PbZn_0.0025In_0.006Se achieves a maximum ZT value of ∼1.3 at 773 K, and the power generation efficiency of its single-leg device reaches 3.4%, demonstrating significant commercialization potential.