The thermoelectric power factor of La0.7Sr0.3MnO3 (LSMO) is closely related to its oxygen-deficient nature. In this study, the oxygen content of mesoporous LSMO films was controlled using various annealing atmospheres (oxygen, nitrogen, air, and argon) to investigate the relationship between oxygen deficiency and the power factor. The effect of the mesoporous structure on the power factor of the prepared LSMO films was also studied through analyses of structural and electrical properties. The oxygen-deficient state induces an increase in the lattice parameter of LSMO, which results in an increase in the electrical resistivity and an enhanced Seebeck coefficient. This phenomenon was emphasized upon the introduction of a pore structure in LSMO because of an increase of the unstable surface area. The oxygen-deficient state results in an increase in the amount of manganese in the Mn3+ valence state and in an increase of the lattice parameter; these effects were confirmed through photoemission spectroscopic analysis. As a result, LSMO can be applied as a thermoelectric material because of the successful preparation of LSMO films with a mesoporous structure and because of the enhancement of the power factor as a consequence of increased oxygen deficiency.
Bibliographical noteFunding Information:
This work was supported by the Center for Advanced Meta-Materials (CAMM) funded by the Ministry of Science, ICT and Future Planning as Global Frontier Project (CAMM-No. NRF-2014M3A6B3063716). This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2015R1A2A1A15054541). Experiments at PLS were supported in part by MEST and POSTECH.
© 2016 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)