Effects of Zr4+-doping on the properties of (Lu, Gd)2O3: Eu transparent ceramics: Insight from the photoluminescent spectra in as-sintered and annealed state.

We show the effects of the Zr4+-doping on the microstructural, optical, and luminescent properties of (Lu, Gd) 2 O 3 : Eu transparent ceramics in its as-sintered state and annealed state. Zr4+-dopant greatly enhanced the transparency of (Lu, Gd) 2 O 3 : Eu ceramic, giving Lu 0.42 Gd 0.5 Zr 0.03 Eu 0.05 O 1.5+δ ceramic with a transmittance of up to 80% at 600 nm. It is found that Zr4+-dopant dominates the luminescent properties of Eu ions in both as-sintered and annealed ceramics. Energy transfer from Eu2+ to Eu3+ was found by photoluminescence spectra, and the ratio of Eu2+/(Eu2++Eu3+) was affected by Zr4+ content in as-sintered ceramics. Moreover, the oxygen vacancy concentration increased with increasing Zr4+ content in as-sintered ceramics. The annealing process enhanced the intensity of all the excitation bands of 4f→4f transitions and the intensity of charge transfer band (CTB) decreased as the Zr4+ content increased in the annealed ceramics. This work highlights that Zr4+ doping is a potential way to improve the transmittance and red emission intensity of 4f→4f transition of Eu3+ in the (Lu, Gd) 2 O 3 : Eu ceramic for extended applications. [ABSTRACT FROM AUTHOR]