SERS and Molecular Orientation in Langmuir-Blodgett Films Deposited onto Smooth Copper Surfaces

Surface-enhanced Raman spectroscopy was applied to the investigation of a hemicyanine dye and a 2-amino-5-nitropyridine derivative as Langmuir-Blodgett layers deposited onto smooth copper surfaces. Ramanspectra of neat materials, thin layers, and LB films on Cu surfaces are reported. SERS enhancement was achieved by using colloidal silver. Orientation of the molecules in the LB films and interactions with the metal substrate are discussed.