The effect of packing density on luminescence of amorphous SiO2 nanoparticles

Abstract

Photoluminescence of amorphous SiO₂ nanoparticles compressed in the form of tablets is studied under exposure to UV radiation. The observed luminescence spectrum is a broad band extending from the excitation wavelength to 700 nm and with a maximum at ~470 nm. The spectrum can be decomposed into two Gaussian components with maxima at ~460 and ~530 nm. As the pressure applied for sample preparation increases, the integrated intensities of these bands change in opposite directions—the intensity of the short-wavelength band increases, while that of the long-wavelength band decreases. It is concluded that these bands are due to different luminescence centers of silicon dioxide located on the surface and in the bulk of SiO₂ nanoparticles.