The effect of self-assembled nanometric spacers on surface enhanced Raman spectra of terthiophene ultrathin films

Self-assembled monolayers (SAMs) of different length have been built onto s ilver surfaces suitable for surface enhanced Raman (SER) effect. The analys is of the surface enhanced Raman spectra as a function of the monolayer thi ckness allowed to study SER effect by changing the distance in a nanometric way. In this work, we present a case of distance dependence in which SER s pectra of terthiophene are studied for molecules deposited onto SAMs previo usly adsorbed on roughened silver. Each spacer is able to inhibit the oligo merization of terthiophene already observed by us, when the molecules are a dsorbed onto bare silver. It will also be shown how the spectral features o f the deposited terthiophene gradually vary by changing the spacer thicknes s from 0.8 to 2.5 nm. (C) 2001 Elsevier Science B.V. All rights reserved.