Xiaoyuan Zhou
College of Physics, Chongqing University, Chongqing, 401331, China

EXTENDED ABSTRACT: Thermoelectric materials enable the direct conversion of heat and electrical power, showing broad application prospects in the fields such as waste heat recovery, solid-state refrigeration, and precise temperature control. One of the key issues for thermoelectrics is how to achieve high carrier mobility in heavily doped semiconductors to ensure high electrical performance. The thermoelectric research team from Chongqing University has proposed several strategies to address this issue such as developing efficient doping method, growing high-quality single crystal, designing intrinsic weak electron-phonon coupling lattice, and constructing ordered twin boundary, which can achieve the regulation of charge transport from the microstructure to electronic level. The report will revolve from the following four strategies: (1) with the introduction of a small number of stabilizing atoms to stabilize high valence cations in thermoelectric materials, the hole concentration can be largely improved without affecting the mobility, achieving significant improvements in power factors in several thermoelectric materials; (2) via preparing high-quality single crystals for compounds with two-dimensional crystal structure and intrinsic low thermal conductivity, the carrier mobility can be dramatically improved, achieving a record thermoelectric figure of merit; (3) we have developed a series of low dimensional materials with planar honeycomb lattice, in which the unique horizontal mirror symmetry can weaken the electron-phonon coupling to achieve high mobility and excellent thermoelectric performance; (4) we have constructed thermoelectric materials with ordered twin boundaries, which enable selective scattering of electrons and phonons to maintain mobility and suppress thermal conductivity.
Keywords:Thermoelectric materials; mobility; single crystal; twin grain engineering