Energy transfer and relaxation in europium-activated Y_(2)O_(3) after excitation by ultraviolet photons

摘要

We present persistence data from the ~(5)D manifolds of europium (3+)-activated Y_(2)O_(3), after excitation by ultraviolet photons. For europium concentrations below 1 at. , the persistence is largely consistent with multiphonon relaxation. For europium concentrations at and above 1 at. , the persistence shows evidence for energy transfer interactions between curopium activators. Interactions involving one activator in an upper (~(5)D_(3), ~(5)D_(2) or ~(5)D_(1)) manifold and another in a ground state (~(7)F) manifold affect the kinetics of the relaxation of the upper ~(5)D manifolds but do not degrade phosphor efficiency. Interactions involving two activators in excited manifolds ultimately dissipate, by phonon emission, excitation that might be emitted as photons. The interactions involving two activators in excited manifolds appear to be related to both concentration quenching and the reduction of phosphor efficiency at high excitation density.