Solvation dynamics of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) in a microemulsion

The photophysical process of the laser dye 4-(dicyanomethylene)-2-methyl-6-(p-dimethylanlinostyryl)-4H-pyran (DCM) is studied in aerosol-OT (AOT) microemulsions in n-heptane using picosecond spectroscopy. When AOT and water are added to a solution of DCM in n-heptane, some of the DCM molecules migrate from bulk n-heptane to the water pool. The absorption and emission peaks of the DCM molecules in the polar water pool are markedly red shifted from those in the bulk n-heptane and the emission intensity in the water pool is nearly 40 times higher. Dual emission is not observed in the microemulsions. DCM exhibits slow solvation dynamics in the water pool with an average solvation time of 1.23 ns. (C) 1999 Elsevier Science B.V. All rights reserved.