Effects of dopant concentration and annealing temperature on the phosphorescence from Zn2SiO4: Mn2+ nanocrystals

The sol-emulsion-gel method is used for the preparation of Mn2+-doped Zn2SiO4 nanoparticles. The luminescence spectra at 520 nm (4T1g→6A1g) and lifetime of the excited state of Mn2+ ions-doped Zn2SiO4 nanocrystals are also found to be sensitive to the annealing temperature (750-1000 deg. C) and concentration (0.25-5 mol%) of ions. We found that at the lowest dopant levels (0.25 mol%, 750 deg. C) the intensity decay kinetic is perfectly described by a single rate. However, with increasing concentration and annealing temperature, the decay was found to be biexponential. The fast component decay is due to the pair or cluster formation and the slow component decay is due to isolated ions at higher concentration