Enhanced emissions of Eu3+ by energy transfer from ZnO quantum dots embedded in SiO2 glass

SiO(2):Eu(3+) based bulk composites containing ZnO quantum dots were synthesized by an in situ sol-gel process. The quantum dots homogeneously distributed among the SiO(2) glass matrix exhibited a broad ultraviolet emission band centered at 385 nm. The ZnO ultraviolet luminescence intensity decreased monotonically with increasing Eu(3+) doping concentration, while the Eu(3+) visible emission was intensified significantly by the precipitation of ZnO quantum dots, ascribed to the energy transfer from ZnO to Eu(3+). The Eu(3+) luminescence at 612 nm for the sample with 20 mol% ZnO was about ten times stronger than that for the sample without ZnO. The influence of ZnO or Eu(3+) concentration on the energy transfer process is discussed.