Defect engineering of rutile TiO2 ceramics: Route to high voltage stability of colossal permittivity. (10th September 2021)

• Record Type: Journal Article
• Authors: Yu, Yang; Zhao, Yu; Qiao, Yu-Long; Feng, Yu; Li, Wei-Li; Fei, Wei-Dong
• Is Part Of: Journal of materials science & technology. Volume 84(2021)
• Page Start: 10
• Page End: 15
• Publication Date: 2021-09-10
• Subjects: Colossal permittivity -- Co-doped TiO2 -- Defect cluster -- Voltage stability; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2020.12.046
• Languages: English
• ISSNs: 1005-0302

Abstract

Graphical abstract: Highlights: The (Ta + Al + La) co-doped TiO2 ceramic with suitable La/Al ratio exhibits colossal permittivity with excellent temperature/frequency stability as well as outstanding dc bias stability. The current density of (Ta + Al + La) co-doped TiO2 ceramic with suitable La/Al ratio is reduced almost four order of magnitude at the same electric field compared with (Ta + La) co-doped ceramic. The results and mechanisms presented in this work open up a feasible route to design high-performance CP materials via defect engineering. Abstract: 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 co-doped 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/Al ratio exhibits colossal permittivity with excellent temperature stability as well as outstanding d c bias stability. The density functional theory analysis suggests that L a 3 + A l 3 + V O T i 3 + defect clusters and Ta 5+ -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.