Graphenic substrates as modifiers of the emission and vibrational responses of interacting molecules: The case of BODIPY dyes.

Graphenic substrates (GS), such as reduced graphene oxide (rGO) and graphene oxide (GO), are 2D materials known for their unique physicochemical properties such as their ability to enhance vibrational spectroscopic signals and quench the fluorescence of adsorbed molecules. These properties provide an opportunity to develop nanostructured GS-based systems for detecting and identifying different analytes with high sensitivity and reliability through molecular spectroscopic techniques. This work evaluated the capacities of different GS to interact with a highly fluorescent compound, thereby changing its optical emission response (fluorescence quenching) and amplifying its vibrational signal, which is the base of graphene-enhanced Raman scattering (GERS). To test these properties, we used a derivative of highly fluorescent BODIPY (BP) compounds, which cover a wide range of applications from solar energy conversion to photodynamic cancer therapy. GS prepared by using the Langmuir-Blodgett (LB) technique allowed us to quench the fluorescence emission of BP and improve its Raman spectroscopy detection limit due to the GERS effect. These results were interpreted in light of the π-π interactions taking place between the Csp domains of GS and the aromatic core of the BP fluorophore.