121st General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code PHYS.P-224
Subject Excited State Dynamics of Dyes Confined in Reverse Micelles
Authors Gisang Lee, Taehyung Jang, YOONSOO PANG*
Department of Chemistry, Gwangju Institute of Science and Technology, Korea
Abstract Photo-induced intramolecular charge transfer (ICT) processes in dye molecules have been of great interest in biology and chemistry fields for the applications to solar energy conversion, photovoltaics, fluorescence sensing, etc. When the electron donor and acceptor groups are connected by π-conjugation bridge inside the chromophore, a torsional relaxation involved with intramolecular charge transfer states is often found. DNBP (4-dimethylamino-4'-nitrobiphenyl) is one of the examples, where two phenyl rings each with donor and acceptor functional groups are connected by a C-C single bond. The torsional angle between two phenyl rings becomes ~40 degrees in the ground state, but the ICT with the changes in the inter-phenyl torsional angle has been found in the excited state upon photo-excitation. The ICT dynamics of DNBP showed strong dependence on the solvent polarity and viscosity. In this research, excited state ICT dynamics of DNBP and related chromophores in various solvents and also in the confined geometry of reverse micelles were investigated by TCSPC (time-correlated single photon counting) and femtosecond transient absorption spectroscopy. Absorption and emission spectra of DNBPs are strongly affected by solvent properties like polarity and viscosity. Moreover, encapsulation of DNBP in reverse micelles provided strong emission enhancements with spectral shifts compared to the case of bulk. Structural changes of DNBPs in the ICT state strongly dependent on the reverse micelle size will also be explored for the confinement effect in the excited state dynamics.
E-mail rltkd0603@gist.ac.kr