Photoluminescence properties of nanocrystalline Tb³⁺ doped Y₂O₃ phosphor prepared through a novel synthetic route

Abstract

Green emitting cubic Y₂O₃:Tb³⁺ nanocrystalline phosphor having particle size of 22 nm was synthesized by TEA (triethanolamine) based precursor solution method. We have characterized our nanocrystalline sample by XRD, HRTEM and Raman spectroscopic measurement. We compared the photoluminescence properties of our nanocrystalline sample with the bulk one. Due to the presence of defect states and lower phonon density of nanomaterials, cross relaxation process seems to be less effective in nanosized sample reflecting higher blue/green ratio in nanosized sample. Relative intensity of ⁵D₄–⁷F₅ transition with respect to ⁵D₄–⁷F₆ transition is reduced in nanosized sample due to greater transition probability of the latter transition in the distorted nanostructured material. Our analysis suggests that change of local environments takes place with decreasing the particle size and it is reflected in the photoluminescence spectra.