Significant Improvement in Electrical Conductivity and Figure-of-merit of Nanoarchitectured Porous SrTiO3 by La Doping Optimization.

: SrTiO3 is a well-studied n-type metal-oxide based thermoelectric material. In this work, the First principle calculation of La doped SrTiO3 has been performed using the density functional theory (DFT). And high thermoelectric properties of bulk SrTiO3 material have been achieved by introducing nano-scale porosity and optimizing carrier concentration by La doping. The X-ray diffraction (XRD), atomic resolution scanning transmission electron microscopy (STEM) imaging and energy dispersive X-ray spectrometry (EDS) results show that La has been doped successfully into the lattice. The SEM images confirm that all the samples have nearly similar nano-scale porosities. The significant enhancement of electrical conductivity over the broad temperature range has been observed through optimization of La doping. Additionally, the samples have very low thermal conductivity, which is speculated due to the nano-scale porosity of the samples. Due to this dual mechanism of doping optimization and nano-scale porosity, there is a remarkable improvement in power factor, 1mW/m2K from 650 K to 800 K and figure of merit, zT of 0.26 at 850 K of the sample, 22 at% La doped SrTiO3.