Interface tuning charge transport and enhanced thermoelectric properties in flower-like SnSe₂ hierarchical nanostructures

Thermoelectric properties could be well improved in hierarchical nanostructures due to the selective scattering on electrons and phonons by interfaces. In this paper, flower-like SnSe₂ nanostructure is synthesized by solution-based method and, the nanostructure is sintered into pellets by spark plasma sintering (SPS) to evaluate thermoelectric properties. It is demonstrated that the flower-like SnSe₂ nanostructure exhibits the ultralow thermal conductivity of 0.44 Wm⁻¹ K⁻¹ due to the strong phonon scattering by high-density of interface and grain boundaries, which have been confirmed by both experiments and simulation. Besides, the electrical transport of the flower-like SnSe₂ is optimized synergistically owing to the moderate interfacial potential barrier. The highest power factor of 43 μWm⁻¹ K⁻² and competitive ZT value are measured at 550 K. The thermoelectric performance of flower-like SnSe₂ is better that that of nanoplate and bulk counterparts. It provides an efficient method to improve the thermoelectric properties of SnSe₂ based materials.