Photophysical parameters and laser activity of 3(4-dimethylamino-phenyl)-1-(2, 5-dimethyl-thiophen-3-yl)-propenone (DDTP): A new potential laser dye

Abstract

The photophysical parameters such as singlet absorption, molar absorptivity, oscillator strength, dipole moment, fluorescence spectra and fluorescence quantum yield of DDTP were measured in different solvents. DDTP dye exhibits red shift in both absorption and emission spectra as solvent polarity increases, indicating that the dipole moment of DDTP dye is higher in excited state than that in the ground state. The density functional calculation were used to obtain the ground state and excited state dipole moments for it has proven to be suitable for calculating electronic excitation energy. A crystalline solid of DDTP gives excimer like emission at 575nm. The absorption and emission spectra of DDTP have been investigated in organized media of aqueous micellar solution. The critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), cetyltrimethyl ammonium bromide (CTAB) and triton X-100 (TX-100) are determined using DDTP dye. Dye solution ca 1×10−3moldm−3 in dimethyl sulfoxide (DMSO) gives laser emission in the range 490–560nm with emission maximum at 520nm upon pumping by nitrogen laser (337.1). The gain coefficient (α) and emission cross section σe at maximum laser emission are also determined.