Nanobiophotonik

Metal-molecule interfaces bare a high potential for application in various fields of chemistry as the features and functions of metal nanostructures can be modified and – to a certain degree - be extended by surface-bound molecules. In the work presented here the functionalization of complex colloidal particles, Au nanopeanuts and Au/Pt/Au nanoraspberries, with the commercially available Ru-complexes N719, N749 and Z907 is reported, which were already applied as photosensitizers in dye-sensitized solar cells. A detailed investigation of the conjugates by means of Raman spectroscopy shows that the electronic structure of the ruthenium complexes is retained upon binding to the the metal nanoparticles. Furthermore, micro-fluidics as an efficient tool for systematic investigations of the SER(R)S signal-enhancement dispersion in colloidal solutions is applied. The enhancement profiles obtained differ from the extinction spectra of the nanoparticles, indicating that electronically resonant processes are involved in the Raman signal enhancement of the investigated nanoparticle conjugates in addition to the Raman signal enhancement observed due to the SERS effect.