Tuning SnSe/SnS hetero-interfaces to enhance thermoelectric performance

With the development of nanotechnology, thermoelectric materials with complex heterogeneous nanostructure offer a promising approach to improve the thermoelectric performance. In this work, SnSe/SnS hetero-nanosheet was tuned by the epitaxial growth of SnSe on the few layers of SnS nanosheets. The heterojunction interface can optimize the carrier/phonon transport behavior by energy filtering effect and scattering the phonon in multiple scales. Compared with pristine SnSe, the power factor of SnSe/SnS hetero-nanosheet increases from 2.2 mu V/cmK( )(2)to 3.21 mu V/cmK(2) at 773 K, whereas the thermal conductivity decreases significantly from 0.65 W . m(-1) . K(-1 )to 0.48 W . m(-1) . K-1 at 773 K. The maximum ZT of 0.5 is obtained at 773 K in the SnSe/SnS hetero-nanosheets, which is 89% higher than pristine SnSe. This approach is proved to be a promising strategy to design high performance thermoelectric materials.