Analysis of bright red-orange emitting Mn2+:ZnAl2O4 spinel nanophosphor

In the present article, undoped and Mn-doped spinel ZnAl2O4 nanophosphors were synthesized by co-precipitation and hydro-thermal methods. The prepared nanophosphors were characterized using powder X-ray diffraction (XRD), Scanning electron microscopy, UV-Visible-Infrared absorption, photoluminescence etc. XRD pattern reveals the formation of cubical ZnAl2O4 nanocrystals of average crystalline size ∼12 nm. The Mn-doped ZnAl2O4 nanophosphors show bright orange − red emission due to the radiative 4T1 → 6A1 transition (593 nm) on excitation with 342 nm radiation. The emission intensity of the prepared nanophosphors was found to be a function of synthesis method and Mn ion concentrations. Emission intensity is found to reduced appreciably in hydrothermal samples. Photophysics involved for emission and other spectroscopic properties were explained.