Multicomponent Synergistic Doping Enables High-efficiency n-Type PbTe Thermoelectric Devices

The development of high-performance n-type PbTe thermoelectric (TE) modules is urgently needed to match those p-type IV-VI tellurides (i.e., PbTe, GeTe, SnTe) with high figure of merit (ZT) to obtain multi-pair TE devices for practical applications. In this work, Ga, Se, and In dopants are progressively introduced into PbTe to optimize the carrier density and band structures and to reduce the lattice thermal conductivity, thereby enhancing the ZT. Consequently, a peak ZT of 1.6 at 773 K and a high average ZT of 1.1 within 300-773 K can be obtained in the optimized sample of Pb_0.979Ga_0.02In_0.001Te_0.96Se_0.04. A mixture of Fe and Sn is further developed as a diffusion barrier material of the n-type PbTe, realizing the preparation of corresponding TE legs by a one-step sintering method, showing low total interfacial contact resistivity (<3 µΩcm²). Finally, a remarkable conversion efficiency of 10.9% at a temperature difference of 449 K can be achieved in the n-type PbTe single-leg TE device. The multicomponent synergetic doping strategy and the interface-connection technique of adding low-temperature metals provide new pathways to improve the performance of n-type PbTe TE devices as well as other TE systems.