We investigated the effect of mesoporous structure on the thermoelectric properties of La-doped SrTiO3 films through the analyses of their structural, electrical, and thermoelectric properties. The mesoporous structure induces a decrease in thermal conductivity and an increase in the Seebeck coefficient because of increased phonon and carrier scattering. The increase of electrical resistivity was smaller than the changes in the Seebeck coefficient and thermal conductivity. As a result, the incorporation of Brij-S10 surfactant into La-doped SrTiO3 films induced an increase of the figure of merit. The maximum value of the figure of merit—approximately 0.025 at 200°C—was obtained with a Brij-S10 molar ratio of 0.1; this figure of merit was approximately 35% higher than that of a La-doped SrTiO3 film without the Brij-S10 surfactant. The results of our study suggest that the mesoporous structure could play a role in enhancing the thermoelectric properties.

Low thermal conductivity, high electrical conductivity, and high Seebeck coefficient are required for thermoelectric materials. To independently control electrical and thermal conductivity, Au nanoparticles were incorporated into mesoporous TiO2 nanocomposite thin films. With increase of Au nanoparticle concentration and annealing time, ordered pore structure gradually collapsed. As porosity and pore structure changed, the electrical resistivity decreased from 142.9 to 41.6 Ω cm. In this work, Au nanoparticle concentration and annealing conditions were investigated to optimize the thermoelectric properties.

The power factor of mesoporous LSMO films was enhanced with an increase in the surface area.