(530e) Exploiting the Optical Properties of Well-Defined Nano-Structures for Photo-Catalytic Applications

Recent progress in solution-based synthetic techniques has allowed the synthesis of Ag nano-structures with well-controlled, highly uniform sizes and particle geometries. These Ag particles exhibit a strong localized surface plasmon resonance (LSPR) due to the nanometer scale spatial confinement and the metal's inherent electronic structure. For nanometer-sized Ag structures, the resonance frequency falls in the ultraviolet to visible light range, and can be tuned by changing the geometry and size of the Ag particles.

Resonant electromagnetic radiation is enhanced in intensity by several orders of magnitude near the surface of plasmonic nano-particles. The concentration of EM fields near plasmonic nano-particles provides a method for increasing photon absorption in nearby semiconducting materials, thereby increasing rates of photo-catalytic reactions. In this work we have utilized a combined theoretical/experimental approach to design composite plasmonic-enhanced semiconducting materials. The composite materials consist of plasmonic Ag nano-particles (wires, cubes and spheres) with resonances that overlap the band gap of photo-catalytically active TiO2 nano-particles. We demonstrate the significant potential of these composite structures in a number of photo-chemical reactions.