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.