1 research outputs found
Macroscopic Strain-Induced Transition from Quasi-infinite Gold Nanoparticle Chains to Defined Plasmonic Oligomers
We
investigate the formation of chains of few plasmonic nanoparticlesî—¸so-called
plasmonic oligomersî—¸by strain-induced fragmentation of linear
particle assemblies. Detailed investigations of the fragmentation
process are conducted by <i>in situ</i> atomic force microscopy
and UV–vis–NIR spectroscopy. Based on these experimental
results and mechanical simulations computed by the lattice spring
model, we propose a formation mechanism that explains the observed
decrease of chain polydispersity upon increasing strain and provides
experimental guidelines for tailoring chain length distribution. By
evaluation of the strain-dependent optical properties, we find a reversible,
nonlinear shift of the dominant plasmonic resonance. We could quantitatively
explain this feature based on simulations using generalized multiparticle
Mie theory (GMMT). Both optical and morphological characterization
show that the unstrained sample is dominated by chains with a length
above the so-called infinite chain limitî—¸above which optical
properties show no dependency on chain lengthî—¸while during
deformation, the average chain length decrease below this limit and
chain length distribution becomes more narrow. Since the formation
mechanism results in a well-defined, parallel orientation of the oligomers
on macroscopic areas, the effect of finite chain length can be studied
even using conventional UV–vis–NIR spectroscopy. The
scalable fabrication of oriented, linear plasmonic oligomers opens
up additional opportunities for strain-dependent optical devices and
mechanoplasmonic sensing