Realize high thermoelectric properties in n-type Bi2Te2.7Se0.3 materials via ZrO2 ceramic nanoparticles mediated heterogeneous interface

Bismuth telluride (Bi2Te3)-based thermoelectric materials have been commercially utilized for refrigeration and energy conversion at room/near room temperature. However, n-type Bi2Te3 compounds always exhibit inferior performance compared with their p-type counterparts, which is pronouncedly impeding Bi2Te3-based energy converters from further optimizations. Herein, a promising ZT value (ZT = 1.33) was obtained in n-type Bi2Te2.7Se0.3 (BTS) materials by using an interface engineering strategy to synergistically optimize the electron and phonon transport properties. In detail, ZrO2 ceramic nanoparticles (NPs) were entered into BTS matrix to construct high-density heterogeneous interfaces. The heterogeneous interfaces strongly scatter phonons and lower energy carriers, leading to decreased thermal conductivity and increased Seebeck coefficient, while the electrical conductivity is not sacrificed due to the compromise of the slightly reduced carrier mobility by interfacial scattering and the increased carrier concentration by ZrO2 NPs doping. A planar module consisting of 127 pairs of p-n single legs were assembled. At the temperature difference of 200 K, the output power and energy conversion efficiency reached 9.6 W and 6.2%, respectively. This strategy provides a feasible way to rationally design advanced n-type Bi2Te2.7Se0.3 materials with excellent thermoelectric and mechanical properties induced by high-density heterogeneous interfaces.