On the Interaction of Carbon Nanowires with Noble Metals through a Study of Their Surface-Enhanced Raman Spectra

This paper deals with the interaction of linear carbon chains (polyynes) with silver and gold surfaces in the form of manometer-sized clusters. Surface-enhanced Raman signals have been detected revealing remarkable differences in the spectroscopic response between the two metals used for the enhancement. These differences are envisaged in the frame of two different interactions leading to different chemical bonds between the probe molecule and the nanoparticles' surface. Surface plasmon resonance measurements support these considerations, whilst the use of self-assembled monolayers (SAMs) allows to evidence the electromagnetic field contribution in the observed SER effect. We studied also the effect of thermal treatments, reaching the conclusion that annealings at moderate temperatures (up to 150 degrees C) affect much more long polyyne chains, increasing also the sp(2) character.