INVESTIGATION OF ELECTRON-TRANSFER BETWEEN HEXAARYLBIIMIDAZOLE AND VISIBLE SENSITIZER

Photoinduced electron transfer between the hexaarylbiimidazole (HABI) and visible sensitizer, 2,5-bis [(2,3,6,7-tetrahydro-1H, 5H-benzo[i,j]quinolizin-1-yl)methylene]cyclopentanone (JAW), in liquid solution was investigated experimentally. The relative fluorescence quantum yield of the sensitizer molecule was measured as a function of HABI concentration. An exponential dependence on HABI concentration was observed for the sensitizer fluorescence yield, from which the critical distance for the electron transfer interaction was determined to be approximately 12 angstrom. The time-dependent fluorescence quenching was studied with the time-correlated single-photon counting technique. The dynamics of the electron transfer process was determined by comparing the experimental data to existing models of electron transfer in liquids. The inclusion of the relative diffusion between the electron donor and acceptor molecules is necessary to fit all the observations and to obtain accurate transfer parameters.