Thermoelectric oxides and oxynitrides with perovskite-type structure

Transition metal oxides with perovskite-type structures are potential high temperature stable thermoelectric materials. The itinerant charge carrier concentration can be tuned for a targeted thermoelectric performance by controlled variation the composition and crystal structure. With innovative soft chemistry synthesis procedures the crystallite size in complex oxide ceramics with perovskite-type structure can be decreased compared to classical synthesis routes and allows to lower the heat conductivity dramatically while a large power factor can be maintained at the same time. Submicron crystallites with an enhanced number of twinned domains are beneficial to lower the lattice thermal conductivity without influencing the electron mobility. In this work, perovskite-type cobaltates, titanates, molybdates and manganates are studied for application as n- and p-type legs of thermoelectric oxide modules. The influence of heterostructures and nanocrystalline domains in perovskite oxides/oxynitrides and the correlation with transport properties and Seebeck coefficient will be discussed.