Luminescent Properties of Doped Zinc Aluminate and Zinc Gallate White Light Emitting Nanophosphors Prepared via Sonochemical Method

摘要

Novel single, double and triple doped ZnAl2O4:M and ZnGa2O4:M (where M = Dy~(3+), Tb~(3+), Eu~(3+) and Mn~(2+)) nanophosphors were synthesized through a simple sonochemical process and characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectrophotometry. The results.of XRD and TEM show that resultant nanoparticles are single phase and have spherical shape. The doped samples showed multicolor emission on single wavelength excitation. Energy transfer was observed from host to the dopant ions. Characteristic blue and yellow emission from Dy~(3+) ions, green from Tb~(3+) ions and red from Eu~(3+) ions were observed. However, the Mn~(2+) ions in zinc gallate host yielded red emission which has been assigned to charge-transfer deexcitation associated with Mn~(2+) ion. The CIE coordinates of ZnGa2O4:Dy~(3+)(2%):Tb~(3+)(0.5%):Mn~(2+)(2.5%)and ZnAl2O4:Dy~(3+)(1.5%):Tb~(3+)(0.25%):Eu~(3+)(0.25%)nanophos-phors are (0.304,0.310) and (0.312,0.307), respectively, which lie in the white light region of the chromaticity diagram.