Low temperature combustion synthesis and photoluminescence mechanism of ZnO/ZnAl2O4 composite phosphors

ZnO, ZnAl2O4 and ZnO/ZnAl2O4 composite phosphors were prepared by one - or two-step low temperature combustion synthesis method. The ZnO, ZnAl2O4 and ZnO/ZnAl2O4 composite phosphors were obtained by auto-ignited combustion of a carbamide-nitrate precursor gel which is produced by a simple thermally induced redox reaction. The crystalline phase attributes, functional groups, surface morphology, optical and photoluminescence properties of the ZnO, ZnAl2O4 and ZnO/ZnAl2O4 composite phosphors were characterized by X-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy, UV-vis spectrophotometer and fluorescence spectrophotometer. The results showed that ZnO/ZnAl2O4 composite phosphors with the type II energy band arrangement were synthesized by two-step low temperature combustion synthesis method. The introduction of zinc oxide into zinc aluminate system improved the crystallinity of zinc oxide and enhanced the optical and photoluminescent properties of the single phase of materials. Based on the energy band theory, the photoluminescence mechanism of ZnO/ZnAl2O4 composite phosphors was proposed.