Correlation between the luminescence properties and the surface structures of submicron silica particles

We investigated the correlation between the luminescence properties and the surface structures of submicron silica particles prepared by the Stöber method. After annealing in a non-oxidizing atmosphere, the submicron-sized silica particles show a broad photoluminescence (PL) band at 500-540 nm by excitation at an ultraviolet wavelengths (254 and 365 nm), and the one at the 600 nm by excitation an Ar+ laser (488 nm). The PL appeared to result from the removal of impurities and subsequent formation of several luminescent structures on the internal surface of the primary particles by thermal annealing.