An aerosol synthesized CeO2:Eu3+/Na+ red nanophosphor with enhanced photoluminescence

Abstract

In this work, CeO₂:Eu³⁺/Na⁺ nanoparticles with high photoluminescence were prepared via a conventional spray pyrolysis process using ethylene glycol (EG) as an organic additive. CeO₂:Eu had intensive emission due to the ⁵D₀ → ⁷F₁ (orange) or ⁵D₀ → ⁷F₂ (red) transition of Eu³⁺. The R/O emission ratio showed a linear increment with the Eu concentration, which was attributed to the reduction in the local symmetry of Eu³⁺-substituted sites. The optimal Eu concentration to achieve the highest emission intensity was 4 at%, and the luminescence quenching was revealed to occur through a dipole–dipole interaction. The use of EG as a chemical additive could prepare CeO₂:Eu nanoparticles of smaller than 80 nm. Also, the emission intensity of nanoparticles was enhanced about 16.5 times higher via codoping Na⁺ with Eu³⁺ in the CeO₂ matrix, which was attributed to the charge compensation as well as the increase of crystallite size. The use of EG and co-dopant Na⁺ was proved to be a simple and excellent way to synthesize highly luminescent nanoparticles via spray pyrolysis.