Properties of sol-gel derived YAG:Eu3+ hierarchical nanostructures with their time evolution studies

Abstract

Eu 3 + doped yttrium aluminum garnet (YAG) nanoparticles were synthesized by sol-gel method. The samples were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy including vacuum ultraviolet (VUV) PL spectroscopy. XRD confirmed that each and every phases of YAG were present, indicating very good quality of sample. The crystallite size, estimated by XRD, increased from 10 to 30 nm with annealing temperatures and significant changes in morphology with annealing temperature was also found in TEM study. The particles were in spherical shape initially but agglomeration of particles started at higher temperatures resulting in hierarchical nanostructures having dimension more than 50 nm. The annealed YAG:Eu3+ hierarchical nanostructures showed strong red luminescence under VUV excitation, corresponding to D50→F72 transition. PL spectra also showed significant increase in luminescence intensity with the increase in annealing temperature. Time evolution studies were also performed continuously for 150 days to check the stability of prepared hierarchical nanostructures and were found to be extremely stable, making them one of the most feasible candidate for red phosphor and seize great potential in flat panel display application that underlies the importance of the current work.