Surface-enhanced Raman scattering from a single molecularly bridged silver nanoparticle aggregate

Temporally fluctuating SERS signals originating from a single specific small aggregate of 4,4′′-diaminoterphenyl (DATP)-bridged Ag nanoparticles are reported. Unequivocal correspondence between the aggregate and the SERS signal obtained from it was achieved by determination of the aggregate position with respect to markers on chemically functionalized, SiOx coated finder grids and its TEM imaging. Since the temporally fluctuating (blinking) SERS signal originates from several hot spots within the aggregate, it cannot be interpreted in terms of a single molecular dynamic event. However, the time-evolution of SERS spectra indicates that the linker decomposes into the graphitic carbon in at least one of these hot spots.