A new photoluminescence emission peak of ZnO–SiO2 nanocomposites and its energy transfer to Eu3+ ions

This work reports a new photoluminescence (PL) emission peak at about 402 nm from amorphous ZnO nanoparticles in a silica matrix, and the energy transfer from it to Eu3+ ions. The amorphous ZnO–SiO2 nanocomposites were prepared by the sol–gel method, which is verified by X-ray diffraction (XRD) profiles and FT–IR spectra. The luminescence emission spectra are fitted by four Gauss profiles, two of which at longer wavelength are due to the defects of the material and the others to amorphous ZnO nanoparticles and the Zn–O–Si interface state. With the reduction of Zn/Si ratio and diethanolamine, the relative intensities of visible emission decrease. The weak visible emission is due to the reduction of defects after calcined at high temperature. The new energy state at the Zn–O–Si interface results in strong emission at about 402 nm. When Eu3+ ions are co-doped, weak energy transfer from ZnO–SiO2 nanocomposites to Eu3+ emission are observed in the excitation spectra.