Self-assembling two-dimensional nanophotonic arrays for reflectivity-based sensing
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Published version
Author(s)
Type
Journal Article
Abstract
We propose a nanoplasmonic platform that can be used for sensing trace levels of heavy metals in solutions via simple optical reflectivity measurements. The considered example is a lead sensor, which relies on the lead-mediated assembly of glutathione-functionalized gold nanoparticles (NPs) at a self-healing water/DCE liquid | liquid interface (LLI). Capillary forces tend to trap each NP at the LLI while the negatively charged ligands prevent the NPs settling too close to each other. In the presence of lead, due to chelation between the lead ion and glutathione ligand, the NPs assemble into a dense quasi-2D interfacial array. Such a dense assembly of plasmonic NPs can generate a remarkable broad-band reflectance signal, which is absent when NPs are adsorbed at the interface far apart from each other. The condensing effect of the LLI and the plasmonic coupling effect among the NP array gives rise to a dramatic enhancement of the reflectivity signals. Importantly, we show that our theory of the optical reflectivity from such an array of NPs works in perfect harmony with the physics and chemistry of the system with the key parameter being the interparticle distance at the interface. As a lead sensor, the system is fast, stable, and can achieve detection limits down to 14 ppb. Future alternative recognizing ligands can be used to build sister platforms for detecting other heavy metals.
Date Issued
2020-09-21
Online Publication Date
2020-10-23T08:06:35Z
Date Acceptance
2020-08-10
ISSN
2041-6520
Publisher
Royal Society of Chemistry (RSC)
Start Page
9563
End Page
9570
Journal / Book Title
Chemical Science
Volume
11
Copyright Statement
© The Royal Society of Chemistry 2020. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence (https://creativecommons.org/licenses/by-nc/3.0/)
Subjects
Science & Technology
Physical Sciences
Chemistry, Multidisciplinary
Chemistry
PLASMONIC NANOPARTICLES
GOLD NANOPARTICLES
COLORIMETRIC DETECTION
PARTICLE-SIZE
MIRRORS
IONS
LEAD
NANOPLASMONICS
CADMIUM
SENSORS
03 Chemical Sciences
Publication Status
Published
Date Publish Online
2020-08-10