Photoluminescence spectroscopy of silica-based mesoporous materials

The experimental study of photoluminescence (PL) at 300 and 90 K from the mesoporous silicas (MSs) [ordered (MCM-41) and disordered (DMSs)] of variously sized pores induced either by ArF laser light (lambda (sub exc) = 193 nm) or by Nd:YAG (yttrium-aluminum-garnet) laser light (lambda (sub exc)=266 nm) is reported. The results reveal that PL spectra measured with 266-and 193-nm excitations are somewhat different because of the different mechanisms of excitation: direct one-proton and indirect through the TP-produced free excitons (FEs), respectively.