Detecting organic molecules using Au nanoparticle dimers with supramolecular interactions

In this work, we have developed a controlled method of functionalization of colloidal nanoparticles in solution based in using rigid molecules as linkers (Cucurbituril molecules) which allow us to obtain reproducible hot spots in gold nanoparticle dimers, due to the control of the gap size between the plasmonic structures with subnanometer precision, and at the same time enables placing analyte molecules precisely within these junctions of ultrahigh field enhancement. This novel protocol allows to obtain dimers of Au NPs using cucurbit[6]uril as linker in a reproducible manner that are stable over several days. The sensing performance of these dimeric structures, is by far superior to previous work using supramolecular interactions, as demonstrated by measuring the SERS response of this system using cucurbituril linker as the host and methyl viologen as the guest molecule.