Heterogeneous catalysts play an important role in surface catalytic reactions, but selective bond breaking and control of reaction products in catalytic processes remain significant challenges. High-vacuum tip-enhanced Raman spectroscopy (HV-TERS) is one of the best candidates to realize surface catalytic reactions. Herein, HV-TERS was employed in a new method to control dissociation by using hot electrons, generated from plasmon decay, as plasmonic scissors. In this method, the N=N bond in 4,4'-dimercaptoazobenzene was selectively dissociated by plasmonic scissors, and the reaction products formed from the radical fragment (SC6H5N) were controlled by varying the pH value. Under acidic conditions, p-aminothiophenol was produced from the radical fragment by attachment of hydrogen ions, whereas under alkaline conditions, 4-nitrobenzenethiol was obtained by attachment of oxygen ions to the substrate.
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http://dx.doi.org/10.1002/chem.201302610 | DOI Listing |
ACS Nano
October 2023
Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, U.K.
Due to the absence of labels and fast analyses, optical biosensors promise major advances in biomedical diagnostics, security, environmental, and food safety applications. However, the sensitivity of the most advanced plasmonic biosensor implementations has a fundamental limitation caused by losses in the system and/or geometry of biochips. Here, we report a "scissor effect" in topologically dark metamaterials which is capable of providing ultrahigh-amplitude sensitivity to biosensing events, thus solving the bottleneck sensitivity limitation problem.
View Article and Find Full Text PDFNatl Sci Rev
August 2022
Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics; International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education; Shenzhen Institute of Translational Medicine; Department of Otolaryngology, Shenzhen Second People's Hospital; the First Affiliated Hospital; Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
The outbreak of the COVID-19 pandemic was partially due to the challenge of identifying asymptomatic and presymptomatic carriers of the virus, and thus highlights a strong motivation for diagnostics with high sensitivity that can be rapidly deployed. On the other hand, several concerning SARS-CoV-2 variants, including Omicron, are required to be identified as soon as the samples are identified as 'positive'. Unfortunately, a traditional PCR test does not allow their specific identification.
View Article and Find Full Text PDFAcc Chem Res
May 2021
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States.
ConspectusHot carriers are highly energetic species that can perform a large spectrum of chemical reactions. They are generated on the surfaces of nanostructures via direct interband, phonon-assisted intraband, and geometry-assisted decay of localized surface plasmon resonances (LSPRs), which are coherent oscillations of conductive electrons. LSPRs can be induced on the surface of noble metal (Ag or Au) nanostructures by illuminating the surfaces with electromagnetic irradiation.
View Article and Find Full Text PDFSci Rep
June 2015
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
We successfully realised plasmon-driven selective reduction reactions of 2-amino-5-nitrobenzenethiol (2A-5-NBT) to 3,3'-dimercapto-4,4'-diaminoazobenzene , an azobenzene derivative, using surface-enhanced Raman scattering (SERS) spectroscopy, and supported by the theoretical calculations. The SERS spectra demonstrated that two 5-nitro groups of 2A-5-NBTs were selectively reduced to the -N=N- chemical bond of 3,3'-dimercapto-4,4'-diaminoazobenzene, whereas the 2-amine group of 2A-5-NBT remained unchanged. Our experimental results revealed that aqueous environments were preferable to ambient atmospheric environments for this selective reduction reaction.
View Article and Find Full Text PDFNano Lett
December 2014
Department of Chemical Engineering, §Applied Physics Program, ∥Biointerfaces Institute, #Department of Materials Science and Engineering, and ○Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
Chiral nanostructures exhibit strong coupling to the spin angular momentum of incident photons. The integration of metal nanostructures with semiconductor nanoparticles (NPs) to form hybrid plasmon-exciton nanoscale assemblies can potentially lead to plasmon-induced optical activity and unusual chiroptical properties of plasmon-exciton states. Here we investigate such effects in supraparticles (SPs) spontaneously formed from gold nanorods (NRs) and chiral CdTe NPs.
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