Colossal seebeck coefficient in aurivillius phase-perovskite oxide composite

Abstract We propose an inexpensive, scalable approach for achieving extremely high values of the Seebeck coefficient (α) by exploiting the natural superlattice structure in Aurivillius phase oxides. In particular, we report an α ≈ 319 mV/K at 300 K in a composite of Aurivillius phase compound SrBi4Ti4O15 (as a matrix) and a perovskite phase material (e.g., La0.7Sr0.3MnO3 or, La0.7Sr0.3CoO3 as filler). Such a colossal value of α may be attributed to contributions from the enhanced density of states due to the effective low dimensional character of the Bi2O2 layer. The corresponding thermal conductivity (κ) and the electrical conductivity (σ) lies in the range 0.7–1.25 W/m-K and 10–100 μS/m, respectively at 300 K. Attributed to the high α values, such oxide composites can be used as suitable materials for thermopile sensors and highly sensitive bolometric applications. We anticipate that the demonstration of colossal α in oxide composites using a simple synthesis strategy also sets the stage for future material innovations for high temperature thermoelectric applications.