Single-Molecule Spectroscopic Investigation of Energy Migration Processes in Cyclic Porphyrin Arrays
journal contributionposted on 28.03.2007, 00:00 by Mira Park, Min-Chul Yoon, Zin Seok Yoon, Takaaki Hori, Xiaobin Peng, Naoki Aratani, Jun-ichi Hotta, Hiroshi Uji-i, Michel Sliwa, Johan Hofkens, Atsuhiro Osuka, Dongho Kim
Covalently linked cyclic porphyrin arrays have been synthesized to mimic natural light-harvesting apparatuses and to investigate the highly efficient energy migration processes occurring in these systems for future applications in molecular photonics. To avoid an ensemble-averaged picture, we performed a single-molecule spectroscopic study on the energy migration processes of cyclic porphyrin arrays and a linear model compound embedded in a rigid polymer matrix by recording fluorescence intensity trajectories, by performing coincidence measurements, and by doing wide-field defocused imaging. Our study demonstrates efficient energy migration within the cyclic porphyrin arrays at the single-molecule level. By comparison with the data of the linear model compound, we could pinpoint the role of the dipole−dipole coupling between diporphyrin subunits and the rigidity of the cyclic structures on the energy transfer processes.