Surface-enhanced Raman scattering of 'push-pull' molecules: Disperse orange 3 adsorbed on Au and Ag nanoparticles

Disperse orange 3 is a typical push–pull chromophore, formed by a p-disubstituted azobenzene with an electron donor aminogroup and an electron-withdrawing nitrogroup at the ends of the molecule. This promotes a large electron mobility over all the π-conjugated system of the molecule and allows a different adsorption on metal depending on the surface properties of the substrate. The SERS spectra indicates that the molecule is adsorbed on gold nanoparticles (NPs) via nitrogroup, whereas the azogroup is involved in the interaction with the silver NPs.