Effect of the geometric shape of Lu2O3: Eu spherical nanocrystals on their spontaneous luminescence

Abstract

Monodisperse red phosphor particles 100 nm in diameter with the Lu1.90Eu0.10O3 composition have been prepared using the developed technique for synthesizing spherical colloidal lutetium oxide particles with a size dispersion in the range 10–15%. The structure of spherical nanoparticles has been investigated, their excitation and photoluminescence spectra have been analyzed, and the lifetime of the 5 D 0 excited state of Eu3+ ions has been considered. It has been found that the luminescence decay time for spherical particles increases by a factor of 1.39 compared to that for a powdered phosphor Lu2O3: Eu (5 at %) prepared and treated under the same temperature conditions as the Lu2O3: Eu (5 at %) spherical particles. This effect has been associated with the change in the photonic local density of states in spherical optical cavities consisting of particles of the phosphor.