Premium
Optical Response of Metallic Nanoparticle Heteroaggregates with Subnanometric Gaps
Author(s) -
Tserkezis Christos,
Taylor Richard W.,
Beitner Jan,
Esteban Rubén,
Baumberg Jeremy J.,
Aizpurua Javier
Publication year - 2014
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201300287
Subject(s) - nanoparticle , chemical physics , nanotechnology , plasmon , excitation , dielectric , metal , chemistry , cluster (spacecraft) , materials science , optoelectronics , physics , organic chemistry , quantum mechanics , computer science , programming language
The optical response of metallic nanoparticle heteroaggregates with well‐defined, subnanometric interparticle gaps is studied both theoretically and experimentally for clusters formed by nanoparticles of different size and/or different material (Au and Ag). The optical spectra of the aggregates can be understood in terms of excitation of chain‐like plasmon modes, which are associated with short and long linear chains that constitute the cluster internally. The dependence of the optical properties of the aggregates on the size of the metallic nanoparticles, the interparticle gaps, and the dielectric environment is revealed in model electromagnetic calculations. A rigid molecular linker, cucurbit[5]uril, is used to experimentally form Au heteroaggregates of different sized particles, as well as heteroaggregates of silver and gold. It is shown that in both types of heteroaggregates, the ratio of the two different nanoparticles provides a versatile and easily controllable way to tailor the dominant long‐wavelength chain mode. Experimental tracing of the optical response of such heteroaggregates in time during aggregation supports the formation of long‐wavelength modes, which can be attributed to excitation of long chains inside the clusters.