During the last decade, a variety of multidimensional chromophore arrays have been prepared to mimic the photosynthetic processes in natural light-harvesting complexes. At the same time, ultrafast spectroscopy has proven to be a good tool for elucidating their photophysical properties, including excitation energy transfer processes. Recently, ultrafast exciton dynamics in multiporphyrin arrays have been extensively investigated by time-resolved spectroscopic techniques such as time-correlated single photon counting and femtosecond transient absorption. The depolarization and exciton-exciton annihilation times could be obtained by time-resolved spectroscopic measurements using Förster-type incoherent energy transfer theory based on dipole-dipole coupling. In this article, the coupling energies of H- and J-type porphyrin aggregates were calculated by matrix diagonalization whose elements are the transition dipole coupling energies, including information on the relative orientation of transition dipoles, distances, and solvents. Analyzing the eigenvalues and eigenvectors obtained by matrix diagonalization, we were able to determine electronically allowed or forbidden transitions. The relationship between molecular structures and transition dipolar interactions exhibited in the steady-state absorption spectra was reexamined and compared with the experimentally observed incoherent energy hopping times in view of exciton coupling.
|Number of pages||15|
|Journal||Journal of Photochemistry and Photobiology C: Photochemistry Reviews|
|Publication status||Published - 2005 Dec|
Bibliographical noteFunding Information:
This work has been financially supported by the National Creative Research Initiatives Program of the Ministry of Science and Technology of Korea. We thank Prof. A. Osuka and his laboratory members at Kyoto University for providing us a variety of porphyrin assemblies to investigate excitation energy migration processes by time-resolved spectroscopy. The authors also greatly thank Prof. Eric Vauthey (University of Geneva, Genève, Switzerland) for his kind discussions.
Dongho Kim was born in Seoul, Korea in 1957. He received a BS in chemistry from Seoul National University (1980) and a PhD from Washington University (1984). After postdoctoral research at Princeton University, he joined the Korea Research Institute of Standards and Science (1986). He moved to Yonsei University (2000), where he is a Professor of Chemistry. Since 1997, he has been leading the Center for Ultrafast Optical Characteristics Control through the National Creative Research Initiatives Program supported by the Korea Science Engineering Foundation.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry