title: Shell-programmed Au nanoparticle heterodimers with customized chiroptical activity.
abstract: Chiral plasmonic assemblies with strong and tunable chiroptical activity are emerging materials yet challenging to fabricate. Moreover, shell-programmed chiroptical regulation is really rare. Here, the chiroptical activity of core-shell (CS) nanoparticles (NPs) heterodimers (HDs) with different types and thicknesses of the shell but featuring the same gap was exploited. It was found that the type of shell guided the position of the chiral peaks, and the shell thickness tuned the intensity but also moderately affected the wavelength shift at invariable interparticle distance. Shell deposition intensified the hot-spot chirality, and evidently guided the enantiomorphous chiral configuration, resulting in a startlingly intense, asymmetric, dipolar coupling strength. The magnitude of the chiroptical activity showed an 8-10 fold enhancement with a maximum anisotropy factor (g-factor) of 1.5 × 10(-2) . Shell-driven chiroptical regulation opens new avenues to feasibly fabricate chiroptically active materials with desired chiroptical response for the development of switchable recognition units for sensitive and various target detections.
authors.affiliation: State Key Lab of Food Science & Technology and School of Food Science & Technology, Jiangnan University, Wuxi, 214122, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Liguang
authors.initials: L
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
authors.forename: Liqiang
authors.initials: L
authors.lastname: Liu
authors.forename: Libing
authors.initials: L
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Kuang
authors.forename: Chuanlai
authors.initials: C
authors.lastname: Xu
keywords: Au; chiroptical response; core-shell particles; gap; heterodimers; nanoparticles; regulation; shell thickness