Wb. Caldwell et al., SELF-ASSEMBLED MONOLAYERS OF FERROCENYLAZOBENZENES ON AU(111) MICA FILMS - SURFACE-ENHANCED RAMAN-SCATTERING RESPONSE VS SURFACE-MORPHOLOGY/, Langmuir, 10(11), 1994, pp. 4109-4115
Surface-enhanced Raman scattering (SERS) and surface-enhanced resonanc
e Raman scattering(SERRS) results are reported for self-assembled mono
layers (SAMs) of 4-(4-mercaptobutyl)-4'-ferrocenylazobenzene compound
1, on Au/mica and Pt/mica thin films. Two different Au/mica surfaces,
designated Au(rough)/mica and Au(111)/mica, have been characterized by
atomic force microscopy (AFM) to define their respective surface morp
hologies. Cyclic voltammetry of SAMs of 1 on Au(rough)/mica, Au(111)/m
ica; and Pt/mica was used to directly measure the surface coverage of
1. A quantitative determination of the contributions to the measured s
urface Raman intensity from adsorbate-localized resonance Raman and su
bstrate-derived electromagnetic enhancement effects is made. The surpr
ising conclusion is that Au(111)/mica surfaces of the type traditional
ly used for preparing and studying SAMs are ''SERS-active'' without th
e need for additional roughening or treatment with a ''SERS-active'' o
verlayer.