Self-templated synthesis and thermal conductivity investigation for ultrathin perovskite oxide nanowires

Abstract

The large thermal conductivity of bulk complex metal oxides such as SrTiO₃, NaCo₂O₄, and Ca₃Co₄O₉ has set a barrier for the improvement of thermoelectric figure of merit and the applications of these materials in high temperature (≥1000 K) thermoelectric energy harvesting and solid-state cooling. Here, we present a self-templated synthesis approach to grow ultrathin SrTiO₃ nanowires with an average diameter of 6 nm in large quantity. The thermal conductivity of the bulk pellet made by compressing nanowire powder using spark plasma sintering shows a 64% reduction in thermal conductivity at 1000 K, which agrees well with theoretical modeling.