title: Asymmetric silver "nanocarrot" structures: solution synthesis and their asymmetric plasmonic resonances.
abstract: Here we report the wet-chemical synthesis of asymmetric one-dimensional (1D) silver "nanocarrot" structures that exhibit mixed twins and stacking fault domains along the <111> direction. Oriented attachment is the dominant mechanism for anisotropic growth. Multipolar plasmon resonances up to fourth order were measured by optical extinction spectroscopy and electron energy-loss spectroscopy (EELS) and are in agreement with theoretical calculations. Compared with those of symmetric 1D nanostructures of similar length, the dipole modes of the nanocarrots show a clear red shift, and the EELS maps show an asymmetric distribution of the resonant plasmonic fields and a compression of the resonance node spacing toward the tail. In addition, increasing the length of the nanocarrots causes an increase in the intensity and a steady red shift of the longitudinal surface plasmon resonance peaks. The silver nanocarrots also show very high sensitivity to the refractive index of their environment (890 ± 87 nm per refractive index unit).
authors.affiliation: INRS-EMT, Université du Québec, 1650 Boul. Lionel-Boulet, Varennes, QC, Canada J3X 1S2.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Liang
authors.forename: David
authors.initials: D
authors.lastname: Rossouw
authors.forename: Haiguang
authors.initials: H
authors.lastname: Zhao
authors.forename: Scott K
authors.initials: SK
authors.lastname: Cushing
authors.forename: Honglong
authors.initials: H
authors.lastname: Shi
authors.forename: Andreas
authors.initials: A
authors.lastname: Korinek
authors.forename: Hongxing
authors.initials: H
authors.lastname: Xu
authors.forename: Federico
authors.initials: F
authors.lastname: Rosei
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Wang
authors.forename: Nianqiang
authors.initials: N
authors.lastname: Wu
authors.forename: Gianluigi A
authors.initials: GA
authors.lastname: Botton
authors.forename: Dongling
authors.initials: D
authors.lastname: Ma
mesh_terms: D053768:Metal Nanoparticles / Q000737:chemistry*; D015394:Molecular Structure; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D012996:Solutions; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D012996:Solutions; D012834:Silver