Abstract
AbstractDeveloping high‐efficiency and environmentally‐friendly thermoelectric materials has been a significant challenge. Conventional thermometric materials consist of heavy (toxic) elements to reduce thermal conductivity (κ), while we demonstrated light‐element hydride anion (H−) substitution in SrTiO3 can largely reduce κ and enhance thermometric efficiency (ZT) without heavy elements. In this paper, we succeeded in maximizing the ZT of SrTiO3−xHx by applying topochemical reaction directly to SrTiO3 epitaxial films with CaH2, which realized wide‐range control of carrier concentration (ne) from 1.5 × 1020 cm−3 to 4.1 × 1021 cm−3. The power factor (PF) showed a dome‐shaped behavior with respect to ne, and the maximum PF = 22.5 μW/(cmK2) was obtained at the optimal ne = 3.4 × 1020 cm−3. Carrier transport analyses clarified that the carrier mobility was limited by impurity scattering of H‐related impurities in the SrTiO3−xHx films, while the hydrogen substitution induced a much lower κ of 4.6 W/(mK) than other heavy‐element substituted Sr1−xLaxTiO3 and SrTi1−xNbxO3 films in the wide ne range, resulting in the higher ZT value of 0.14 in maximum at room temperature. In addition, the ZT increased to 0.17 at 373 K due to the large decrease in κ for a SrTiO3−xHx film with the hydrogen concentration of 1.2 × 1021 cm−3. Further study on H− substitution approach and modulation of the H state in transition metal oxides would lead to development of high ZT environmentally‐friendly thermoelectric materials.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call