화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.116, No.11, 3490-3503, 2012
Photoinduced Energy Transfer in Bichromophoric Pyrene-PPV Oligomer Systems: The Role of Flexible Donor-Acceptor Bridges
In this contribution, we report on the electronic energy transfer dynamics of bichromophoric systems incorporating two pyrene chromophores tethered by variable-length flexible alkyloxy chains to p-phenylenevinylene oligomers. These were studied using UV-vis absorption and both steady state and time-resolved fluorescence spectroscopy. Time-resolved emission measurements showed an efficient photoinduced energy transfer process in all the multichromophoric systems, which occurs on the time scale of tens of picoseconds after excitation at 265 nm. The energy transfer process is especially efficient in systems where the linker is formed by eight atoms (up to k(ET) approximate to 2.7 X 10(10) s(-1)), which, despite not being the shortest bridge studied, allows the approach of the donor and acceptor chromophores due to an appropriate number of flexible single bonds. Using Forster theory, we calculated the donor-acceptor distance in each triad from the experimental energy transfer rate, finding them to be in the range 8.8-10 angstrom.