Sol–gel synthesis and luminescent properties of SiO2/Zn2SiO4 and SiO2/Zn2SiO4:V composite materials

Abstract

Undoped and vanadium-doped Zn2SiO4 particles embedded in silica host matrix were prepared by a simple solid-phase reaction after the incorporation of ZnO and ZnO:V nanoparticles, respectively, in silica monolith using the sol–gel method with supercritical drying of ethyl alcohol in two steps. After supercritical drying and annealing in the temperature range between 1423 and 1473K in an air atmosphere, the photoluminescence (PL) measurements show a band centered at about 760nm in the case of non-doped Zn2SiO4 which is attributed to energy transfer from Zn2SiO4 particles to NBOHs interface defects. In the case of vanadium doped Zn2SiO4, the PL reveals a band centered at about 540nm attributed to the vanadium in the interfaces between Zn2SiO4 particles and SiO2 host matrix. Photoluminescence excitation (PLE) measurements show different origins of the emission bands. The PLE band (∼240–350nm) may be understood as an energy transfer process from O2− to V5+ which occurs intrinsically in the vanadyl group.