Fluorescence Quenching Study of Nano Graphene Oxide Interaction with Naphthalimide Dye: Thermodynamic and Binding Characteristics

A quenching study was reported for interacting a fluorescence naphthalimide derivative with graphene oxide (GO) as a quencher. 1,8-naphthalimide fluorophore with two amine functional side arms (NN2) was synthesized and characterized. Many different 1,8-naphthalimide fluorescence dye derivatives have been designed for fluorescence probe application. Fluorescence quenching-based platforms in nanoscale have extensively been used in sensing systems. Raman, FTIR, UV-Vis, and fluorescence spectroscopic techniques were used to study GO and NN2 characteristics and their photophysical and quenching mechanisms at different temperatures. The results indicated that graphene plays an effective quencher against the naphthalimide molecule, with quenching efficiently at 91 %. The Stern-Volmer analysis results show a mix of static and dynamic quenching mechanisms. The binding constant of the quencher and fluorophore and the number of binding sites have been reported. Thermodynamic parameters of their interaction were evaluated. The negative values of the ΔG confirm that the complexation process is spontaneous. Meanwhile, the positive entropy value confirms the favourable pathway process. </em>