Comprehensive linear photophysical and photochemical characterization, two-photon absorption (2PA) properties, and femtosecond excited-state dynamics of a symmetrical fluorene derivative 2-(2,6-bis((E)-2-(7-(diphenylamino)-9,9- dihexyl-9H-fluoren-7-yl)vinyl)-4H-thiopyran-4-ylidene)malononitrile (1) are reported. The linear one-photon absorption (1PA), steady-state fluorescence, excitation, and excitation anisotropy spectra of 1 were investigated in organic solvents of different polarities at room temperature, exhibiting rather complex absorption and emission behavior. The relatively strong 2PA of thiopyranyl 1 was investigated by the open aperture femtosecond Z-scan technique in the main long wavelength 1PA contour with maxima cross sections up to 600-700 GM. Femtosecond dynamics of the excited-state absorption (ESA) and gain processes in 1 exhibited fast complicated relaxation phenomena with a strong dependence on solvent polarity and a weak dependence on excitation wavelength. The nature of the observed transient absorption kinetics was explained based on the short-lived ESA bands of 1 and solvate relaxation phenomena. Quantum chemical calculations, based on density functional theory, were employed for additional analysis of the 1PA and 2PA properties of 1.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films