Defect engineering of rutile TiO2 ceramics: Route to high voltage stability of colossal permittivity

Donor-acceptor co-doped rutile TiO2 ceramics with colossal permittivity (CP) have been extensively investigated in recent years due to their potential applications in modern microelectronics. In addition to CP and low dielectric loss, voltage stability is an essential property for CP materials utilized in high-power and high-energy density storage devices. Unfortunately, the voltage stability of CP materials based on codoped TiO2 does not catch enough attention. Here, we propose a strategy to enhance the voltage stability of co-doped TiO2, where different ionic defect clusters are formed by two acceptor ions with different radii to localize free carriers and result in high performance CP materials. The (Ta +Al + La) co-doped TiO2 ceramic with suitable La/A1 ratio exhibits colossal permittivity with excellent temperature stability as well as outstanding dc bias stability. The density functional theory analysis suggests that La3+Al (3+VOTi3+)-Ti-center dot center dot defect clusters and Ta5+-Al (3+) pairs are responsible for the excellent dielectric properties in (Ta +Al + La) co-doped TiO2. The results and mechanisms presented in this work open up a feasible route to design high performance CP materials via defect engineering. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

A strategy to enhance the voltage stability of co-doped TiO2 ceramics has been proposed, resulting in the successful design and synthesis of high-performance CP materials (Ta +Al + La) co-doped TiO2, which exhibit colossal permittivity, excellent temperature stability, and outstanding dc bias stability. The results and mechanisms provide a feasible route to design high-performance CP materials via defect engineering.