Luminescence and EPR studies of Y2O3:Gd3+ phosphors prepared via solution combustion method

Gadolinium-activated Y2O3 phosphor has been prepared by combustion process in a short time of 5 min. The phosphors are well characterized by X-ray diffraction, scanning electron microscopy, and energy-dispersive analysis of X-ray. The as-prepared Y2O3:Gd powder shows that all the peaks are due to the Y2O3 cubic phase. Upon UV light excitation (276 nm), the phosphor exhibits a strong and sharp UV emission at 314 nm and is ascribed to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ ^{ 6} {\text{P}}_{ 7/ 2} \, {\to}\, ^{ 8} {\text{S}}_{ 7/ 2} $$\end{document} transition of Gd3+ ions. The EPR spectrum of Y2O3:Gd phosphor exhibits resonance signals with effective g values at g = 1.96, g = 2.88, and g = 6.08 and are attributed to Gd3+ ions located at sites with weak, intermediate, and strong cubic symmetry fields, respectively. It is observed that the population of spin levels (N) and linewidth depends on temperature. The paramagnetic susceptibility (χ) is also evaluated as a function of temperature and discussed.