Optical and Photoluminescence Properties of the MgAl₂O₄:M (M = Ti, Mn, Co, Ni) Phosphors: Calcination Behavior and Photoluminescence Mechanism

Abstract

MgAl₂O₄:M (M = Ti, Mn, Co, Ni) phosphors were successfully prepared by a modified polyacrylamide gel method. Calcination temperature and metal particle has significant effects on the phase transition, optical and color properties of Mg Al₂O₄: M phosphors. Ti, M n, Co and Ni metal particles introduced into the MgAl₂O₄ system can produce a variety of colours from white, grayish black, blue to turquoise blue. Mn, Co and Ni metal particles added into MgAl2O4 system can extend their light absorption to visible light range, while the Ti metal particles clad into the system did not improve significantly. Co metal particles appended into the MgAl2O4 system can cause fluorescence quenching of emission peak at 395 nm and enhancement of emission peak at 405 nm, while the Ti and Mn metal particles infused into the system can bring the enhancement of visible emission peak at 425 nm. The fluorescence quenching of the peak at 395 nm can be ascribed to the wavelength of Co metal particles matching the surface plasmon absorbance band of MgAl₂O₄:M phosphor. A reduction in emission intensity at 425 nm can be assigned to electron transfer from the conduction band (CB) of MgAl₂O₄ to the CB of metal particles causing non-radiative decay.

GRAPHICAL ABSTRACT

Keywords:

• Phosphor
• Optical properties
• Calcination temperature
• Fluorescence quenching
• Non-radiative decay