Wide-range modulation and micro-identification of the plasmonic behaviour in gas phase-deposited silver nanoparticle arrays

Abstract

The surface plasmon resonance properties of silver cluster-deposited multi-structured nanoparticle arrays are investigated for various substrate surfaces. A remarkable redshift from 396 to 572 nm is observed on Formvar film-decorated substrate with controlled particle coverage under in situ surface plasmon resonance wavelength monitoring. The redshift induced by the electromagnetic near-field couplings between the silver nanoparticles and the tuning of the local surface plasmon resonance wavelength in the nanoparticle arrays is found to be correlated to the fraction of closely spaced particle-pairs. Plasmonic ruler behaviour of the closely spaced particle-pair fraction is established and used as an indicator on a gradient silver nanoparticle micro-assembly for identifying the local surface plasmon resonance property in nanostructures. With a 473 nm laser probe, the featured surface plasmon resonance of the optimal nanoparticle assembly for surface-enhanced Raman scattering is found to be around 515 nm.

Keywords:

• Surface plasmon resonance
• Nanoparticle array
• Silver cluster
• Near-field coupling