Y ₂ O ₂ S : Eu ³⁺ nanocrystals—synthesis and luminescent properties

Luminescent Y2O2S : Eu3+ nanoceramics having an average particle size of 20 nm has been prepared through a gel–polymer thermolysis process employing a urea–formaldehyde resin. In this nanocrystalline system, large blue shifts (in relation to the bulk system) of ∼5000 cm−1 and ∼2000 cm−1 in the photoluminescence excitation bands corresponding to the excitonic region and the Eu3+–ligand charge transfer region respectively have been observed. These may be explained by considering possible size dependent changes in optical electronegativity and quantum confinement effects occurring in this large bandgap semiconductor system.