Plasmon Coupling in Two-Dimensional Arrays of Silver Nanoparticles: II. Effect of the Particle Size and Interparticle Distance

The effect of the particle size and interparticle distance on the coherent plasmon coupling was studied in 2D arrays of silver nanoparticles. The plasmon coupling leads to the formation of a cooperative plasmon mode characterized by an intense and narrow peak in the blue spectral range. The arrays were fabricated via the self-assembly of the nanoparticles on poly(4-vinylpyridine)-modified glass substrates. Changing the ionic strength of the aqueous nanoparticle suspension prior to the self-assembly provided a possibility for controlling the interparticle distance in the arrays. The study revealed an optimum particle size around 86 nm and the corresponding optimum interparticle distance of about 107 nm for the strongest plasmon coupling, as determined from the most intense and sharpest resonance that was observed in water. Changing the dielectric medium will conceivably result in different values for the optimal particle size and interparticle distance.