Comparative triplet studies of 7-amino 4-methyl coumarin laser dye in nafion membranes and in homogeneous solutions

Abstract

The triplets of 7-amino 4-methyl coumarin (Cl²⁰), a laser dye, were studied in benzene as well as in a polymeric membrane, (Nafion-117). The triplet lifetimes and T---T absorption spectra were determined. The T---T energy transfer studies between biphenyl-C120 and C120-thionine were carried out in the membrane and the results compared with those obtained in benzene. Due to very slow diffusion of the dye, the energy transfer rates are very low and they are not very efficient compared with other deactivation processes. Effect of counter-ion on the fluorescence lifetimes and triplet yields were studied to see heavy atom effect inside the nafion membrane.