Systematic tuning of the luminescent properties of self-activated ZnGa2O4 phosphors by Cd ion substitution

Abstract

The effect of host compositions on the luminescent properties of spinel-type ZnGa2O4 phosphors was investigated by systematic substitution of Cd2+ for Zn2+ in the host lattice. A continuous solid solution with the composition (Zn1-xCdx)Ga2O4 (0 less than or equal to x less than or equal to 1.0) was synthesized at 950 degrees C as self-activated phosphors, as indicated by X-ray diffraction (XRD) analysis. With increasing substitution of Cd2+ the emission and excitation wavelengths (lambda(cm) and lambda(exc)) of self-activated (Zn1-xCdx)Ga2O4 were observed to exhibit a red shift, as indicated by photoluminescence spectral analysis. Similar results were also confirmed by cathodoluminescence data. Our observations are attributed to the systematic narrowing of the energy gap of the host attributed to expanding lattice dimensions induced by Cd2+ substitution. A CIE: chromaticity diagram manifests the effect of Cd2+ doping on variation of hue for the (Zn1-xCdx)Ga2O4 gallate phosphors. (C) 2000 Academic Press.