Metal nanoparticles in gel-derived oxide coating films: control and application of surface plasma resonance

Surface plasma resonance (SPR) of metal nanoparticles embedded in dielectric media was briefly reviewed on the basis of electromagnetic theory, where how SPR can enhance the oscillating field of light was illustrated. It was stressed that any photoexcitation processes can be enhanced by SPR as long as they occur at SPR wavelength, and this serves a basis for innovative SPR-assisted optical functions. In order to utilize SPR for enhancing a photoexcitation process of interest, SPR characteristics such as wavelengths should be controlled. Sol-gel method was shown to have great advantages in controlling SPR characteristics through controlling the metal particle size, shape and orientation and selecting the surrounding media A recent attempt to develop materials of SPR-assisted photoelectrochemical functions was also described.