LAUSR

In this work, the static and dynamic fluorescence analyses of direct yellow 27 [C 25 H 20 Na 2 O 9 S 3 ] had been carried out through fluorescence spectroscopic techniques in various polar protic and polar aprotic solvents at room temperature. The prominent emission peak of the molecule observed at 355.84 nm in water, and the Stokes shift of the order of 68.84 nm (Δν = 6741 cm −1 ) came out. We found the recorded emission peak to be slightly redshifted with increase in polarity of the solvents. The excited-state lifetime measurement of the molecule in different solvents studied and determined that mono-azo direct yellow 27 possessed a lifetime of 12.18 ns in DMSO and 6.8 ns in the water at a concentration of 100 µM. The fluorescence quantum yield (Φ f ) calculated as 0.41 in water and the impact of different solvents on its value also analyzed.