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Visible laser–induced photoreduction of silver 4‐nitrobenzenethiolate revealed by Raman scattering spectroscopy
Author(s) -
Kim Kwan,
Lee Yoon Mi,
Lee Hyang Bong,
Park Yeonju,
Bae Tae Yeol,
Jung Young Mee,
Choi Cheol Ho,
Shin Kuan Soo
Publication year - 2010
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2432
Subject(s) - raman spectroscopy , photochemistry , raman scattering , chemistry , surface enhanced raman spectroscopy , silver nanoparticle , molecule , argon , spectroscopy , analytical chemistry (journal) , nanoparticle , materials science , nanotechnology , organic chemistry , physics , quantum mechanics , optics
We have investigated the photochemical characteristics of silver 4‐nitrobenzenethiolate (Ag‐4NBT) by means of Raman spectroscopy. When Ag‐4NBT is irradiated with an argon ion laser at 514.5 nm, its Raman spectrum changes over time, resulting in the production of 4NBT‐capped silver nanoparticles. The surface‐enhanced Raman scattering (SERS) spectrum of 4NBT adsorbed on those Ag nanoparticles is subsequently converted to that of 4‐aminobenzenethiol (4ABT). These surface‐induced photoreduction characteristics were investigated by monitoring the growth of Raman peaks of 4ABT as a function of the laser exposure time. Water vapor or ambient conditions were more effective than vacuum conditions for the photoreduction of 4NBT to 4ABT. Nonetheless, the occurrence of photolysis even under vacuum conditions suggests that the benzene ring hydrogen atoms might be the H‐atom source of the nitro‐to‐amine group conversion although in ambient conditions water or solvent molecules trapped inside the Ag‐4NBT should be the primary H‐atom source and facilitate the transfer of electrons, as well as the diffusion of Ag atoms to form highly SERS‐active nanoaggregates. Copyright © 2009 John Wiley & Sons, Ltd.