The near infrared-emitting Zn2SiO4 powders were produced by high-energy planetary ball milling of ZnO and SiO2 powders followed by annealing in air environment and at different temperatures. The surface morphology, crystal structure, chemical composition and optical properties of the obtained samples were investigated by means of field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy and photoluminescence measurements (PL) at room temperature. The analysis indicates the formation of Zn2SiO4 phase with annealing temperature of 1250 oC.°C. The size of Zn2SiO4 nanoparticles depends strongly on annealing temperature. Photoluminescence investigation reveals that the optimal annealing temperature for almost only near-infrared emission (~740 nm) is 1250 oC. The origin of this peak can be attributed to the energy transfer from non-bridging oxygen hole centers (NBOHs) to zinc interstialinterstitial (Zni) and oxygen vacancy (Vo) states in the Zn2SiO4 host lattice. These results demonstrate that we might be able to produce the Zn2SiO4 powders for applications in high CRI white light emitting diodes by a simple and low-cost method.
Preparation of graphene oxide by dry planetary ball milling technique under oxygen atmosphere
