Light induced behavior of xanthene dyes with benzyl viologen

The light induced processes of xanthene dyes with benzyl viologen have been studied by steady state and time resolved fluorescence spectroscopic measurements in aqueous medium. Steady state quenching is due to ground state complex formation and it is further verified by unaltered fluorescence lifetime. The strength of interaction between xanthene dyes and BV has been evaluated by Benesi–Hildebrand and Stern–Volmer methods. The role of halogen substitution on photophysics of xanthene dyes and with benzyl viologen has been studied. Non-halogenated dye molecule (fluorescein) is not interacting with benzyl viologen, on the other hand halogen loaded xanthene derivatives were interacting well with benzyl viologen through ground state complex formation. This fundamental work may be useful for energy harvesting devices towards the applications of solar cells.