Gold Nanoparticle Dimers for Plasmon Sensing

Abstract

In this study, gold nanoparticles (GNP) were stabilized for the first time as dimers by a conducting polymer (CP). The morphology of kissing particles was examined by high-resolution transmission electronic microscopy (HRTEM). The broad-band localized surface plasmon resonance (LSPR) tunable by solvent variation and molecular binding was demonstrated by UV-vis measurement. The sensitivity of the longitudinal LSPR to the surrounding media or the binding of a biomolecule was 6 times higher than that of the transversal LSPR. A homogeneous bioassay was directly developed from the highly stable GNP-CP dimers with LSPR as prober, and protein sensing with detection limit well below 100 ng/mL was achieved.

Enhanced performance of polymer solar cells with a monolayer of assembled gold nanoparticle films fabricated by Langmuir–Blodgett technique

“…Fig. 2a shows the UV-vis spectra of these Au NPs dissolved in chloroform, and the SPR absorption spectra red-shifts as the particle size increases, similar to the previous reports [26][27][28]. The maximum SPR absorption peak for 3 nm particles locates at 512 nm and has been red-shifted to 546 nm for 16 nm Au particles.…”

“…The SPR property of the noble metallic nanoparticles is originated from the collective resonant oscillation of conduction electrons under optical excitation, which is highly related to the nanoparticle size and shape, local dielectric environment, and nanoparticle arrangement [26][27][28]. Thermal evaporation [20] and electrodeposition [29] are two common methods for depositing metal nanoparticles upon ITO substrates for solar cell application, while these methods lead to poor control over the nanoparticle size and shape.…”

Plasmonic Gas Sensing Using Nanocube Patch Antennas

“…While individual particle resonances can be effectively tuned through size, shape and material choice, [ 2,12 ] coupled modes between two or more nanoparticles have been shown to exhibit far greater electric fi eld enhancements and produce more sensitive detectors. [13][14][15][16][17][18] However, these are extremely diffi cult to fabricate, with many top-down lithographic and FIBbased examples being unrealistic for scaling up, and bottom-up techniques that generally produce randomly oriented particle pairs with no control over the alignment, which is key as the resonances of such dimers are highly sensitive to the polarization of incident illumination. Henzie et al made some important progress in this fi eld by using a gravity-driven technique to assemble nanoparticles in shallow pits in a substrate, which allows excellent control over orientation and positioning of any number of particle sets.…”

Optofluidics incorporating actively controlled micro- and nano-particles

“…The applications of such optofluidic devices are mostly found in areas of particle manipulation [177][178][179][180] and sensing. 88,181 Commonly in many plasmonic measurements and manipulations, metal (such as gold or silver) nanostructures or nanoparticles are used to provide the enhancement for surface plasmons. The systems are either based on prefabricated nanostructured surfaces (such as surfaces with arrays of nano-posts and nano-roughened surfaces) or agglomerated nanoparticles.…”