Controlled synthesis and optimum luminescence of Sm~(3+)-activated nano/submicroscale ceria particles by a facile approach

摘要

Rare-earth Sm~(3+)-activated nano/submicroscale ceria particles were prepared by a rapid combustion reaction. Characterized with X-ray diffraction patterns and Raman spectra, the formation of solid solution was confirmed after Sm~(3+) doping into ceria, and the concentration of oxygen vacancies in the host was gradually increased with the increase of Sm~(3+) doping content. Assisted by polyvinyl alcohol (PVA) in the combustion reaction process, the morphology of the particles was well distributed and the particle size was controlled from nano (10 nm) to submicro (~250 nm), depending on the post-sintering temperature. More interesting was that the samples could be effectively excited with 370 nm and emitted strong orange-red light after optimization, which was suitable for the demands of high-efficiency UV LEDs. Without the addition of PVA, the samples showed very weak luminescence even after lengthy sintering. However, the samples prepared by PVA-assisted combustion synthesis exhibited remarkably enhanced emission after an appropriate heat treatment. The quenching concentration of activator Sm~(3+) was 1.5 mol%, and the optimal luminescence intensity reached nearly 10-fold in comparison with that of samples prepared by conventional solid state reaction. The Sm~(3+)-activated nano/submicroscale ceria materials have potential for use in solid state lighting.