Stable dispersions of surfactant-coated TiO2–Ag based nanoparticles inapolar medium have been prepared by performing sequentially the hydrolysis oftitanium(IV) isopropoxide and the reduction of Ag? in the confined space of sodiumbis(2-ethylhexyl)sulfosuccinate (NaAOT) reverse micelles. Depending on thesequence length, this novel procedure allowed the synthesis of semiconductor–metalnanoparticles, nominally indicated as TiO2/Ag, TiO2/Ag/TiO2, and TiO2/Ag/TiO2/Ag, stabilized by a monolayer of oriented surfactant molecules. The structuralcharacterization of these nanoparticles has been performed by High ResolutionTransmission Electron Microscopy (HR-TEM), while optical properties wereinvestigated by UV–Vis absorption and fluorescence spectroscopies. TEM investigationshowed the presence of globular nanoparticles with an average diameter ofabout 10 nm composed by distinct amorphous TiO2 and crystalline Ag glueddomains whose structure depends on the sequence length. UV–Vis absorptionmeasurements highlighted the mutual metal–semiconductor influence on the TiO2energy band gap and on the Ag plasmon resonance. Steady-state fluorescencespectra analysis allowed to reveal the strong inhibition of the electron–hole radiativerecombination in the TiO2 domains due to the Ag and the appearance of a newemission band centred in the 484–545 nm range. Possible attributions of theinvolved electronic transition of this last emission are discussed.
|Number of pages||3|
|Journal||Journal of Cluster Science|
|Publication status||Published - 2010|
All Science Journal Classification (ASJC) codes
- General Chemistry
- General Materials Science
- Condensed Matter Physics