High thermoelectric performance realized through manipulating layered phonon-electron decoupling
Lizhong Su, Dongyang Wang, Sining Wang, Bingchao Qin, Yuping Wang, Yongxin Qin, Yang Jin, Cheng Chang, Li‐Dong Zhao
Abstract
Thermoelectric materials allow for direct conversion between heat and electricity, offering the potential for power generation. The average dimensionless figure of merit ZT ave determines device efficiency. N-type tin selenide crystals exhibit outstanding three-dimensional charge and two-dimensional phonon transport along the out-of-plane direction, contributing to a high maximum figure of merit Z max of ~3.6 × 10 −3 per kelvin but a moderate ZT ave of ~1.1. We found an attractive high Z max of ~4.1 × 10 −3 per kelvin at 748 kelvin and a ZT ave of ~1.7 at 300 to 773 kelvin in chlorine-doped and lead-alloyed tin selenide crystals by phonon-electron decoupling. The chlorine-induced low deformation potential improved the carrier mobility. The lead-induced mass and strain fluctuations reduced the lattice thermal conductivity. Phonon-electron decoupling plays a critical role to achieve high-performance thermoelectrics.