Enhanced optical properties of Ag-TiO2 (rutile) hybrid nanopowder

A strong surface-enhanced Raman scattering (SERS) from TiO2 nanoparticles i s firstly obtained in a nanostructural Ag-TiO2 calabash-like hybrid particl e powder synthesized by gamma-radiation combined with a hydrothermal treatm ent. Visible luminescence, due to the interband transitions of TiO2 nanopar ticles, is broadened by excitation transfer from Ag nanoparticles. All Rama n scattering bands of TiO2 are enhanced with incorporation of Ag particles, including the low frequency broad band at about 110 cm(-1). which might be disorder induced. The strong electric field from the surface plasmon excit ation of Ag particles causes the novel optical response of TiO2 ultrafine p articles. The plasmon resonance shifts toward the red and the enhancement f actor obtained is as large as 10(3).