Optical and photochemical properties of sodium dodecylbenzenesulfonate (DBS)-capped TiO₂ nanoparticles dispersed in nonaqueous solvents

Abstract

TiO₂ nanoparticles capped with sodium dodecylbenzenesulfonate (DBS) have been synthesized so that they can be dispersed in many organic and nonaqueous solvents. It has been found that DBS-capped TiO₂ nanoparticles have a significant red shift of the optical absorption band edge and clear photoluminescence at room temperature in contrast to that of bare TiO₂ nanoparticles. The results obtained indicate that the surface structure, that is, the capping group and the defect states, plays an important role in the electronic states of TiO₂ nanoparticles. The recombination dynamics of the photoexcited charge carriers (electron and hole pairs) of DBS-capped TiO₂ as studied by picosecond transient absorption spectroscopy is found to be much slower as compared to that of bare TiO₂ nanoparticles as reported earlier.