The sol-emulsion-gel method is used for the preparation of Eu 3+ doped Zn 2SiO 4 nanoparticles. The luminescence spectra at 613 nm ( 5D 0 → 7F 2) and lifetime of the excited state of Eu 3+ ions doped Zn 2SiO 4 nanocrystals are also found to be sensitive to the concentration (0.25-2.5 mol%) of ions. In case of 1000 °C annealed sample (0.25 mol% Eu 3+) showed the single component decay of 2.02 ms. However, with increasing the concentration the decay is biexponential. We attribute this to an inter-ion exchange interaction wherein the more rapid decay is due to pair or cluster formation and the longer-lived emission originates from isolated ions within the insulating host.