Effect of montmorillonite clay on the fluorescence resonance energy transfer between two cationic dyes Acridine Orange and Rhodamine B in solution

Abstract

In this article the Fluorescence resonance energy transfer (FRET) between two important cationic dyes namely Acridine Orange (AO) and Rhodamine B (RhB) in aqueous solution in presence and absence of montmorillonite (MMT) is demonstrated. The energy transfer is also studied in ethanolic solution. Excited state energy migration is occurred from AO to RhB molecules and the extent of energy transfer efficiency linearly increases with increase in RhB concentration in the solution. Interestingly the incorporation of MMT clay significantly increases the energy transfer efficiencies between the dye pair in the solution but the nature of interaction depends on the clay concentrations studied in the present work. The nature of quenching of steady state fluorescence emission of AO in presence of RhB as well as MMT clay in the mixed ensemble is systematically investigated and further confirmed by Time-resolved fluorescence and temperature-dependent steady state fluorescence emission experiments. AO and RhB dye molecules formed ground state complex with MMT clay followed by static quenching. As the clay platelets successfully control the FRET efficiency and it is also well known that MMT clay can host wide diversity of molecular species therefore, the present studies may provide a new insight for the design and the development of FRET-based molecular sensors.