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Tip‐enhanced Raman spectroscopy (TERS) of malachite green isothiocyanate at Au(111): bleaching behavior under the influence of high electromagnetic fields
Author(s) -
Pettinger Bruno,
Ren Bin,
Picardi Gennaro,
Schuster Rolf,
Ertl Gerhard
Publication year - 2005
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.1332
Subject(s) - malachite green , raman spectroscopy , chemistry , adsorption , substrate (aquarium) , spectroscopy , analytical chemistry (journal) , electromagnetic field , plasmon , excitation , surface enhanced raman spectroscopy , raman scattering , molecule , surface plasmon , photochemistry , materials science , optics , optoelectronics , physics , oceanography , electrical engineering , quantum mechanics , chromatography , engineering , geology , organic chemistry
Tip‐enhanced Raman spectroscopy (TERS) was investigated with malachite green isothiocyanate adsorbed at an Au(111) surface. TERS is based on the excitation of localized surface plasmons in the tip apex, producing strongly enhanced electromagnetic fields. The key conditions for giant TERS are side‐illumination of the tip, well‐prepared single‐crystalline surfaces and sharp, smooth gold tips. A TERS enhancement of about 6 × 10 6 has been observed for dye molecules adsorbed at the Au(111) substrate in a region of about 50 nm diameter beneath the tip. This corresponds to a 2500‐fold increase in the light intensity at the Au(111)/air interface, which in addition causes fast but local bleaching of the dye. This bleaching behavior was analyzed in detail, giving direct insight into the strength and size of the enhanced field. In addition, the bleaching constant was higher for MGITC in an unperturbed environment than for MGITC in an environment that had been substantially bleached. The MGITC spectra were also different for these two cases. Copyright © 2005 John Wiley & Sons, Ltd.