RGB emission of Mn2Â + doped zinc phosphate glass

We report the photoluminescence (PL) of Mn2 + doped zinc phosphate glass as melted. Raman, X-Ray diffraction (XRD), Energy-Dispersive X-ray Spectroscopy (EDS) were used to get a better characterization. During the synthesis process, the Mn2 + ions, tetrahedrally coordinated (IVMn2 +) in the glass, partially precipitate on octahedral sites (VIMn2 +) that gives place to the simultaneous occurrence of green and red luminescence, due to the spin-forbidden 4T1(G) → 6A1(S) and 4T1g(G) → 6A1g(S) transitions in IVMn2 + and VIMn2 + respectively. The ratio IVMn2 +/VIMn2 + can be controlled by the increase of %Mn in the glass and, hence, the ratio between green and red emissions can be controlled. The change of Mn2 + ions coordination form 4 to 6 is seen by Electron Paramagnetic Resonance (EPR) and lifetime measurements. PL results indicate the precipitation of crystalline ZnO phases with relatively small particle size that produces its characteristic blue emission due to conduction band to valence band exciton transitions. The transition 6A1(S) → 4E(D) of Mn2 + centered at 350 nm can produce a blue and red dual luminescence by the overlap with the valence band to conduction band transition of ZnO, while the transition 6A1(S) → 4A1(G) of Mn2 + centered at 409 nm produces the green and red dual luminescence that is dependent on %Mn in the glass.