Synergistic Material‐Interface Engineering: Unlocking Superior Performance in PbSe Thermoelectric Modules

The scarcity of tellurium (Te) critically restricts the large-scale deployment of advanced thermoelectric technologies. Here, Te-free PbSe is demonstrated as a cost-effective alternative for both power generation and solid-state cooling through crystal growth, a two-step compositional optimization, and multilayer interface engineering. Light Te alloying (<1%) effectively suppresses lattice thermal conductivity while preserving high carrier mobility, and subsequent trace Bi substitution (<0.2‰) optimizes carrier concentration without degrading carrier mobility, yielding a high power factor of ≈37.5 µW cm^-1 K^-2 and excellent thermoelectric performance (ZT≈0.6 at 300 K and a peak ZT≈1.3 at 773 K). Furthermore, replacing conventional Ni contacts with MgNi+Cu multilayers reduces interfacial resistivity by more than twofold. Benefiting from these advances, a segmented leg with an average ZT above 1.0 over 300-773 K achieves a conversion efficiency of ≈9.5%, while a 7-pair module delivers a maximum cooling temperature difference of ≈63.2 K. These results establish PbSe as a cost-effective and competitive candidate for high-performance thermoelectric power generation and solid-state cooling across wide operating temperatures.