Article abstract
Nature Physics 2, 631 - 635 (2006)
doi:10.1038/nphys389
Subject Categories: Condensed-matter physics | Chemical physics | Electronics, photonics and device physics | Polymer physics
Exciton scattering and localization in branched dendrimeric structures
Chao Wu1, Sergey V. Malinin1, Sergei Tretiak2 and Vladimir Y. Chernyak1
Abstract
-conjugated dendrimers are molecular examples of tree-like structures known in physics as Bethe lattices. Electronic excitations in these systems can be spatially delocalized or localized depending on the branching topology. Without a priori knowledge of the localization pattern, understanding photoexcitation dynamics reflected in experimental optical spectra is difficult. 'Supramolecular'-like quantum-chemical calculations quickly become intractable as the molecular size increases. Here we develop a reduced exciton-scattering (ES) model, which attributes excited states to standing waves in quasi-one-dimensional structures, assuming a quasiparticle picture of optical excitations. Direct quantum-chemical calculations of branched phenylacetylene chromophores are used to verify our model and to derive relevant parameters. Complex and non-trivial delocalization patterns of photoexcitations throughout the entire molecular tree can then be universally characterized and understood using the proposed ES method, completely bypassing 'supramolecular' calculations. This allows accurate modelling of excited-state dynamics in arbitrary branched structures.
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, Michigan 48202, USA
- Theoretical Division, Center for Nonlinear Studies, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
Correspondence to: Sergei Tretiak2 e-mail: serg@lanl.gov
Correspondence to: Vladimir Y. Chernyak1 e-mail: chernyak@chem.wayne.edu
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