Relation between Fluorescence Spectroscopy and Dynamic Light Scattering Revealed by Interaction of Transition Metal Sulfide Nanoparticles and Graphene Oxide

The binding efficiency of graphene oxide and selected transition metal sulfide nanoparticles (Co₃S₄, NiS, CuS, and ZnS) observed by fluorescence spectroscopy, and corresponding changes observed in the hydrodynamic size by DLS are related to each other. We observed that changes in the size of nanoparticles before and after binding have a similar pattern to the estimated binding constants, which shows a relationship between fluorescence spectroscopy and dynamic light scattering. This relation is yet unknown in the literature to the best of our understanding. Further, the binding mechanism is dependent on the nature of nanoparticles, where ZnS nanoparticles have highest binding towards graphene oxide, followed by CuS, Co₃S₄, and NiS nanoparticles respectively. The electronic interaction of the aromatic double bonds of GO with the nanoparticles is revealed along with both static and dynamic binding mechanisms. The stability of nanocomposites is also investigated for these titration experiments of nanoparticles and graphene oxide.