Self-doped Ce3+ enhanced CeO2 host matrix for energy transfer from Ce3+ to Tb3+

Abstract

Ceria has been widely investigated due to its astonishing properties caused by oxygen vacancies and the facile conversion between Ce³⁺ and Ce⁴⁺. We synthesized luminescence tuneable ceria-based CeO₂:Tb³⁺,Ce³⁺ nanoparticles, in which Ce³⁺ was self-doped. Excess Ce³⁺ ions give rise to energy transfer from Ce³⁺ to Tb³⁺ in CeO₂:Tb³⁺,Ce³⁺ nanoparticles. These nanoparticles show intensity tuneable green luminescence, a long lifetime and low photobleaching in water. Reactive oxygen species (ROS) can be scavenged by these nanoparticles due to the high ratio of Ce³⁺/Ce⁴⁺ in ceria. The luminescence intensity of CeO₂:Tb³⁺,Ce³⁺ nanoparticles is sensitive to H₂O₂ (a ROS) concentrations. With increased H₂O₂ concentration, the luminescence intensity of CeO₂:Tb³⁺,Ce³⁺ nanoparticles is decreased gradually. The emission intensity can be recovered by treating with ascorbic acid, and this cycling can be repeated, which reveals good anti-fatigue properties of CeO₂:Tb³⁺,Ce³⁺ nanoparticles. These attractive properties make CeO₂:Tb³⁺,Ce³⁺ nanoparticles potential materials for ROS detection.