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

Abstract

The sol–emulsion–gel method is used for the preparation of Mn²⁺-doped Zn₂SiO₄ nanoparticles. The luminescence spectra at 520 nm (⁴T_1g→⁶A_1g) and lifetime of the excited state of Mn²⁺ ions-doped Zn₂SiO₄ nanocrystals are also found to be sensitive to the annealing temperature (750–1000 °C) and concentration (0.25–5 mol%) of ions. We found that at the lowest dopant levels (0.25 mol%, 750 °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.