Fabrication of core/shell structured SiO2/Zn2SiO4:Mn2+ composite and its photoluminescence properties

Core/shell structured SiO2/Zn2SiO4:Mn2+ composite was prepared by thermal-diffusion reaction between SiO2 and Zn1−xMnxO particles, which is a low cost solid-state method. The X-ray diffraction and scanning electron microscope results showed that a 5-μm-thick dense Zn2SiO4:Mn2+ layer was successfully formed on the surface of the SiO2 particles. The PL spectrum of the SiO2/Zn2SiO4:Mn2+ composite revealed a green emission peak at 526 nm with PL intensity 20% higher than that of the conventional Zn2SiO4:Mn2+ particles. In addition, the decay time of the SiO2/Zn2SiO4:Mn2+ composite was shorter (τ10% = 7 ms) than that of the conventional Zn2SiO4:Mn2+ particles (τ10% =12 ms), which is owing to the relaxation of forbidden transition of Mn2+ ions due to the localized stress of Mn2+ ions arising from the surface tension in the SiO2/Zn2SiO4:Mn2+ composite.