dark plasmon of adjacent silver hexagonal nanoplates dimer

Silver hexagonal nanoplates (hnps) were fabricated by solution phase method. it is observed that most of hexagonal nanoplates prefer that they be placed adjacent to each other, when they are deposited on glass substrate. hence, the near-field enhancement in silver hexagonal nanoplate dimer is studied in detail using the discreet dipole approximation method. the effect of interparticle separation (dimer gap) and surrounding medium on the distribution pattern and magnitude of the near-field enhancement is analyzed. our results show that there are three plasmonic bands for dimer separation 2 and 4 nm. the obtained results show that the highest value of the figure of merit (fom) is about 15 which is related to third band of dimer with gaps 4 nm. moreover, this mode shows extreme sensitivity to the interparticle gap distance and surrounding refractive index, which shows great promise for high sensitivity localized surface plasmon resonance (lspr) sensing.