Off-Center Distortions and Resonant Levels: A Pathway to Enhance Power Generation and Thermoelectric Cooling in PbSe Crystals
Siqi Wang, Shulin Bai, Pengpeng Chen, Shaoping Zhan, Yu Tian, Lei Wang, Dongrui Liu, Jiayi Peng, Yichen Li, Dezheng Gao, Tian Gao, Zhiyao Zhang, Zhan Si, Yuxiang Wei, Hongyao Xie, Xiang Gao, Yingcai Zhu, Yi Wen, Li‐Dong Zhao
Abstract
The scarcity of tellurium (Te) poses significant challenges to the widespread application of Bi 2 Te 3 -based thermoelectric systems. In this work, we investigated the potential of Te-free PbSe for thermoelectric applications by optimizing carrier mobility through crystal growth and a two-step strategy of light alloying and doping. First, Cd alloying was employed to reduce the lattice thermal conductivity ( κ lat ) of n-type PbSe through the off-center effect while preserving carrier mobility. Subsequent In doping enhanced the effective mass via the resonant level formation, achieving a high weighted mobility-to- κ lat ratio ( μ W / κ lat ∼338.4) and a large power factor of 36.7 μW cm –1 K –2 at 300 K in the Pb 0.9972 Se-0.008Cd-0.0008In crystal. Due to the reduced lattice thermal conductivity and largely promoted μ W / κ lat value, the optimized Pb 0.9972 Se-0.008Cd-0.0008In crystal exhibited a large ZT value of ∼0.5 at 300 K, a maximum ZT value of ∼1.3 at 673 K, and an average ZT value of ∼1.1 (300–773 K). Additionally, a thermoelectric generator based on the Pb 0.9972 Se-0.008Cd-0.0008In crystal achieves a power generation efficiency of 6.3%, while a 7-pair module (n-type Pb 0.9972 Se-0.008Cd-0.0008In crystal and p-type commercial Bi 0.4 Sb 1.6 Te 3 material) demonstrated a maximum cooling temperature difference (Δ T ) of 51.2 K ( T h = 353 K). This work establishes PbSe as a cost-effective, high-performance thermoelectric material for thermoelectric cooling and power generation.