paper

Colossal Seebeck coefficient in Aurivillius Phase-Perovskite Oxide Composite

arXiv:2007.00632 · doi:10.1016/j.jallcom.2020.157001

Abstract

We propose an inexpensive scalable approach for achieving extremely high values of Seebeck coefficient ( $I^\pm$ ) by exploiting the natural superlattice structure in Aurivillius phase oxides. In particular, we report an $I^\pm \approx$ 319\,mV/K at 300\,K in a composite of Aurivillius phase compound SrBi $_{4}$ Ti $_{4}$ O $_{15}$ (as a matrix) and a perovskite phase material (e.g., La $_{0.7}$ Sr $_{0.3}$ MnO $_{3}$ or, La $_{0.7}$ Sr $_{0.3}$ CoO $_{3}$ as filler). Such a colossal value of $I^\pm$ can be attributed to contributions from the enhanced density of states due to the effective low dimensional character of Bi $_{2}$ O $_{2}$ layer. The corresponding thermal conductivity ( $I^º$ ) and the electrical conductivity ( $I ¨ $ ) lies in the range 0.7 - 1.25 W/m-K and 10 - 100 $I^¼$ S/m, respectively at 300\,K. Attributed to the high $I^\pm$ values, such oxide composites can be used as thermopile sensors and highly sensitive bolometric applications. We anticipate that the demonstration of colossal $I^\pm$ in oxide composites using a simple synthesis strategy also sets the stage for future material innovations for high temperature thermoelectric applications.

5 figures, 1 table