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Plasmon-induced near-infrared fluorescence enhancement of single-walled carbon nanotubes

Amirjani, A ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1016/j.carbon.2022.03.040
  3. Publisher: Elsevier Ltd , 2022
  4. Abstract:
  5. Single-walled carbon nanotubes (SWCNTs) emit near-infrared (NIR) fluorescence that is ideal for optical sensing. However, the low quantum yields diminish the sensor's signal-to-noise ratio and limits the penetration depths for in vivo measurements. In this study, we perform a systematic investigation of the plasmonic effects of Ag and Au nanoparticles of various geometries to tune and even enhance the fluorescence intensity of single-stranded DNA-wrapped SWCNTs (ssDNA-SWCNTs). We observe a chirality-dependent NIR fluorescence enhancement that varies with both nanoparticle shape and material, with Au nanorods increasing (7, 5) and (7, 6) chirality emissions by 80% and 60% and Ag nanotriangles increasing (7, 5) and (6, 5) emissions by 200% and 240%, respectively. The chirality-dependent enhancement was modeled using finite element modeling (FEM), which confirms contributions not only from a plasmon-induced localized increase in electron density but also from the radiative recombination of dark exciton states from the resulting electromagnetic field. Finally, we demonstrate the application of these nanoparticles in enhancing the single-molecule fluorescence of individual SWCNTs imaged in a custom-built confocal setup. The plasmonically coupled sensors show four orders of magnitude greater sensitivity towards ferricyanide, a model analyte, compared to the non-coupled sensors. Plasmonic nanoparticles thus provide a tunable means of modulating SWCNT fluorescence to study fundamental transitions of otherwise forbidden states and to improve the optical sensing performance. © 2022 The Authors
  6. Keywords:
  7. Nanospheres ; Silver ; Single-walled carbon nanotubes (SWCNTs) ; Chirality ; DNA ; Electromagnetic fields ; Fluorescence ; Gold nanoparticles ; Image enhancement ; Infrared devices ; Plasmonic nanoparticles ; Plasmonics ; Signal to noise ratio ; Single-walled carbon nanotubes (SWCN) ; Stereochemistry ; Fluorescence enhancement ; In-vivo measurement ; Nanotriangles ; Near-infrared fluorescence ; Noise limit ; Optical sensing ; Plasmonic hot spots ; Sensor signals ; Single-walled carbon ; Single-walled carbon nanotube ; Nanorods
  8. Source: Carbon ; Volume 194 , 2022 , Pages 162-175 ; 00086223 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0008622322002123