Investigations about oligothiophene donor-acceptors systems

Full text: Recently, in our group a new synthetic pathway has been developed for getting a donor-acceptor π-conjugated fullerene-oligothiophene-fullerene triad compound in which the three constituents are linked covalently by two ethynyl bridges. Starting from this potentially interesting compound we performed photophysical steady-state and transient pump-probe measurements in solution in order to study the electron dynamics processes involved after the photoexcitation. In parallel, electronic structure calculations have been performed on some related donor-acceptor systems with different electron acceptor groups (e.g., -Br; –CHO and -ethynyl). The results of exploratory quantum chemical methods were used to evaluate the energetics of excited electronic states and the absorption spectra as well as the nature of the excitations. In this work the agreement between experimental and TD-DFT data will be reported and discussion about the role of solvents during the charge transfer process will be presented. (author)