TY - INPR A1 - Lambert, Christoph A1 - Völker, Sebastian F. A1 - Koch, Federico A1 - Schmiedel, Alexander A1 - Holzapfel, Marco A1 - Humeniuk, Alexander A1 - Röhr, Merle I. S. A1 - Mitric, Roland A1 - Brixner, Tobias T1 - Energy Transfer Between Squaraine Polymer Sections: From helix to zig-zag and All the Way Back T2 - Journal of the American Chemical Society N2 - Joint experimental and theoretical study of the absorption spectra of squaraine polymers in solution provide evidence that two different conformations are present in solution: a helix and a zig-zag structure. This unique situation allows investigating ultrafast energy transfer processes between different structural segments within a single polymer chain in solution. The understanding of the underlying dynamics is of fundamental importance for the development of novel materials for light-harvesting and optoelectronic applications. We combine here femtosecond transient absorption spectroscopy with time-resolved 2D electronic spectroscopy showing that ultrafast energy transfer within the squaraine polymer chains proceeds from initially excited helix segments to zig-zag segments or vice versa, depending on the solvent as well as on the excitation wavenumber. These observations contrast other conjugated polymers such as MEH-PPV where much slower intrachain energy transfer was reported. The reason for the very fast energy transfer in squaraine polymers is most likely a close matching of the density of states between donor and acceptor polymer segments because of very small reorganization energy in these cyanine-like chromophores. KW - energy transfer dynamics KW - squaraine polymer Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159607 UR - http://dx.doi.org/10.1021/jacs.5b03644 N1 - This document is the unedited Author's version of a Submitted Work that war subsequently accepted for publication in Journal of the American Chemical Society, copyright American Chemical Society after peer review. To access the final edited and published work see doi:10.1021/jacs.5b03644. ER -