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

Novel single, double and triple doped ZnAl2O4:M and ZnGa2O4:M (where M = Dy3+, Tb3+, Eu3+ and Mn2+) 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 oil single wavelength excitation. Energy transfer was observed from host to the dopant ions. Characteristic blue and yellow emission from Dy3+ ions, green from Tb3+ ions and red from Eu3+ ions were observed. However, the Mn2+ ions in zinc gallate host yielded red emission which has been assigned to charge-transfer deexcitation associated with Mn2+ ion. The CIE coordinates of ZnGa2O4:Dy3+(2%):Tb3+(0.5%):Mn2+(2.5%) and ZnAl2O4:Dy3+(1.5%):Tb3+(0.25%):Eu3+(0.25%) nanophosphors are (0.304,0.310) and (0.312, 0.307), respectively, which lie in the white light region of the chromaticity diagram.