Systemically tuning the surface plasmon resonance of high-density silver nanoparticle films.

A systemical modulation on the frequency of the surface plasmon resonance (SPR) band of high density silver nanoparticle arrays is demonstrated by depositing gas phase silver clusters on substrate surface with a controlled particle coverage under in-situ SPR spectra monitoring. With increasing the density of the Ag nanoparticles, the SPR wavelength shows a redshift from less than 400 nm to more than 570 nm. The tuning of the SPR wavelength is found to correlate to the increase of the fraction of closely spaced nanoparticle pairs that are near-field coupled with the deposition mass. The coverage dependent SPR properties are also compared with the results from discrete dipole approximation (DDA) calculations. [ABSTRACT FROM AUTHOR]