The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect.

ABSTRACT: (Co, Nb) co-doped rutile TiO2 (CoNTO) nanoparticles with low dopant concentrations were prepared using a wet chemistry method. A pure rutile TiO2 phase with a dense microstructure and homogeneous dispersion of the dopants was obtained. By co-doping rutile TiO2 with 0.5 at.% (Co, Nb), a very high dielectric permittivity of ε' ≈ 36,105 and a low loss tangent of tanδ ≈ 0.04 were achieved. The sample-electrode contact and resistive outer-surface layer (surface barrier layer capacitor) have a significant impact on the dielectric response in the CoNTO ceramics. The density functional theory calculation shows that the 2Co atoms are located near the oxygen vacancy, creating a triangle-shaped 2CoVoTi complex defect. On the other hand, the substitution of TiO2 with Nb atoms can form a diamond-shaped

SUBMITTER: Nachaithong T 

PROVIDER: S-EPMC8198226 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature