Rare Earth Free Oxide Nano-Composite of SrTi0.85Nb0.15O3 and CNT for Potential N-Type Thermoelectrics

Despite having large electron concentration, the electrical conductivity of Nb doped SrTiO(3 )severely suffers from poor carrier mobility. Even after taking several attempts by different research groups, it is still challenging to improve carrier mobility without affecting the Seebeck coefficient. In this report, 1-dimensional CNT has been introduced in SrTi0.85Nb0.15O3 (STN) matrix to fabricate STN + CNT nano composites as CNT is expected to have boosted the mobility by several orders. We have reported more than 1000 % increase in electrical conductivity after CNT addition. In contrast, Seebeck coefficient remains flat with CNT loading. This remarkable enhancement of electrical conductivity accompanied by essentially no change in thermopower leads to a 380 % increase in the ZT parameter. Although CNT has been previously introduced in chalcogenides, binary oxides, and oxy-chalcogenides, such a remarkable surge in electrical transport with the incorporation of a small amount of CNT has never been reported. Moreover, to the best of our knowledge, this is the first report on thermoelectric properties of oxide perovskite composites with CNT. Our results suggest that forming oxide-CNT nano-composites can be a robust strategy to improve the thermoelectric performance in bulk materials for realistic applications.