Synthesis and characterization of donor-bridge-acceptor molecule containing tetraphenylbenzidine and perylene bisimide

A novel donor acceptor dyad consisting of tetraphenylbenzidine (TPD) and perylene bisimide was synthesized by linking these moieties using a dodecyl spacer. HOMO and LUMO values of the dyad were aquired by cyclic voltammetry. Photophysical properties were studied by steady-state UV-vis and fluorescence spectroscopy. After selective excitation of the TPD moiety, a quenching of donor fluorescence and the appearance of acceptor fluorescence was observed. This proves nonradiative energy transfer from the donor to the acceptor group. The energy transfer was 4 times more efficient in DBA than in a mixture of D and A. The energy transfer efficiency in the dyad is also independent of the concentration, indicating intramolecular transfer mechanism. However, the direct excitation of the acceptor in the dyad exhibited reduced fluorescence emission of the acceptor, indicating electron transfer between the moieties. Thus, this DBA is an excellent model system for the study of energy- and electron-transfer processes in organic semiconductors.