Eu3+ dopped yttrium oxysulfide nanocrystals – crystallite size and luminescence transition(s)

Nanocrystals of yttrium oxysulfide doped with trivalent europium has been synthesized using a two step sol–gel polymer thermolysis method employing urea formaldehyde resin in the presence of ethylene diamine tetra acetic acid as chelating agent. In this synthesis, marginal tunability in crystallite size (/ ¼ 7–15 nm) was achieved by varying the concentration of reactants and organic precursors. In this nanocrystalline system, various luminescence transitions, in particular 5D0!7F2 transition of Eu3þ shows moderate (~ 60%) lifetime shortening which can be explained by considering possible increase in non-radiative rate (snr) and also possible modification in optical electronegativity induced by surface states of the crystallites