Combustion synthesis and luminescent properties of the Eu3+-doped yttrium oxysulfide nanocrystalline

Nanocrystalline Y2O2S:Eu3+ was successfully prepared with a combustion synthesis method, the corresponding bulk Y2O2S:Eu3+ was synthesized by conventional sulfur flux method. The results of XRD indicated that both bulk and nanocrystalline Y2O2S:Eu3+ have pure hexagonal phases. The crystallite size was calculated to be about 20 nm according to Scherrer formula, which was consistent with the size as indicated by transmission electron microscopy (TEM). The charge-transfer transition bands in nanocrystalline Y2O2S:Eu3+ shift to higher energy in contrast to the bulk material. By combining centroid shift and crystal-field splitting, the blue-shift of the charge-transfer (CT) band is interpreted.