Graphene oxide-controlled neutral cationic form of a red emitting dye: enhancement of fluorescence by graphene oxide.

Fluorescence enhancement of fluorophores in neat solvent media in the presence of graphene oxide (GO) is less known. It is necessary to re-examine the role of GO from the fundamental scientific viewpoint. Herein, we have reported GO controlled conversion from the neutral to cationic form of a red emitting molecule.

Graphene Oxide as an Enhancer of Fluorescence.

Solvent-dependent switching of graphene oxide (GO) as fluorescence quencher or enhancer was observed. In some solvents, GO increases the fluorescence yield of a hydrophilic molecule 7-(diethylamino)-coumarin-3-carboxylic acid (7-DCA), and in some solvents GO act as a quencher of fluorescence.

Host-guest interaction of 3-hydroxyflavone and 7-hydroxyflavone with cucurbit [7]uril: A spectroscopic and calorimetric approach.

The modulation of photophysical behaviour of small organic molecules in the presence of macrocycles is one of the most interesting areas of research. In this work we reported the interaction of two biologically active molecules 3-hydroxyflavone and 7-hydroxyflavone with macrocyclic host cucurbit [7]uril in aqueous medium. To investigate the change of photophysical properties of these two flavones, we have used steady state absorption, fluorescence, time resolved fluorescence emission spectroscopy and isothermal titration calorimetric technique.