Abstract

Nanostructured mesoporous silica thin film has been deposited on silicon substrate by the spin-coating technique using CTAB as a template under acidic conditions. TGA, SEM, HRTEM, N2 adsorption-desorption isotherm, FTIR and synchrotron high flux beamline were used to characterize the microstructure and photoluminescence properties of the resulting film. After being calcined at 400 °C for 12 h, the thin film exhibited a very smooth surface and interconnected pores, with a pore size of about 1-2 nm. The synchrotron photoluminescence spectra show that the samples after calcination have three obvious luminescence peaks around 322, 387 and 410 nm arising from nonbridging oxygen hole centers (NBOHCs) and Si-OH surface complexes. The UV emission (322 nm) due to NBOHCs is inhibited by H2 plasma treatment, indicating that the nonbridging oxygen was saturated by the hydrogen atoms.

Keywords: Mesoporous silica, UV light, photoluminescence, spin-coating technique, hydrogen atoms, nonbridging oxygen, H2 plasma treatment, synchrotron radiation