An Investigation Of The Fluorescence Quenching Properties And Raman Spectra Of Graphene

The development of a reliable Tip Enhanced Raman Spectroscopy (TERS) system will revolutionize the imaging and manipulation of materials at the nanoscale. However, Raman signals are inherently weak and greatly overshadowed by fluorescence. This summer we focused on two main goals. The first goal was to grow monatomic layers of graphene on Cu foils via a chemical vapor deposition process and to transfer the samples to a silicon substrate. We have successfully produced few layer graphene (<10 layers) and confirmed these results using AFM and Raman spectroscopy.  Raman spectroscopy has also been used to analyze the quality of the graphene samples through direct comparison with graphite.  This data was used to develop a reliable and reproducible procedure for growing high quality single layer graphene.  The second research goal is to qualitatively analyze the fluorescence quenching properties of graphene. We hope to achieve this by examining the Raman spectra of several aromatic compounds when adsorbed to graphene. Compounds such as anthracene, pentacene, and pyrene were chosen for initial studies since these compounds not only fluoresce in the UV-Vis range, but are also Raman active. Gaining understanding of graphene’s fluorescence quenching behavior will better allow for its future use as a substrate for chemically patterned surfaces to be analyzed via TERS.