Photophysical properties of TICT molecule adsorbed on semiconductor titania–silica colloids

The effect of semiconductor titania–silica colloids on the fluorescent properties of adsorbed 4-(4′-N,N-diethylaminophenyl-3,5-dimethyl-1,7-diphenyl-bis-pyrazolo-[3,4-b, 3′-e]-pyridine (DEA-DMPP) has been studied by steady-state and time-resolved fluorescence spectroscopy. 3,5-dimethyl-1,7-diphenyl-bis-pyrazolo-[3,4-b,3′-e]-pyridine (DMPP) in presence of N,N-dimethylaniline has been employed as the system simulating the separate electron acceptor and electron donor subunits of DEA-DMPP molecule. Silica and titania–silica colloid surfaces inhibited the formation of the intramolecular charge transfer state (ICT) of adsorbed DEA-DMPP due to formation of H-bonds between the amino group of DEA-DMPP and OH-groups localized on the surface.