Blocking effect of TiO2 colloids on the excited state isomerization of a cyanine dye

Abstract Fluorescence dynamics of a cyanine dye 3,3′-di(3-sulfopropyl)-thiacyanine triethylaminium salt in water with and without doping TiO 2 colloids has been investigated using the femtosecond time-resolved fluorescence up-conversion technique. A new component with a decay time larger than 30 ps for the dye molecules associated with TiO 2 was observed and a blocking effect of TiO 2 on the conformational isomerization process of the cyanine dye is suggested.