Chemical Sciences, Geosciences, and Biosciences Division National Science Foundation (NSF) OSTI Identifier: 1399126 Grant/Contract Number: FG02-99ER14999 DGE-1324585 Resource Type: Journal Article: Accepted Manuscript Journal Name: ACS Applied Materials and Interfaces Additional Journal Information: Journal Volume: 9 Journal Issue: 39 Journal ID: ISSN 1944-8244 Publisher: American Chemical Society (ACS) Country of Publication: United States Language: ENGLISH Subject: 36 MATERIALS SCIENCE organic photovoltaics femtosecond transient absorption spectroscopy EPR GIWAXS self-assembly thin films charge = , Advanced Photon Source (APS) Sponsoring Org.: USDOE Office of Science (SC), Basic Energy Sciences (BES). Publication Date: Fri Apr 21 00:00: Research Org.: Argonne National Lab. Argonne-Northwestern Solar Energy Research Center (ANSER) Northwestern Univ., Evanston, IL (United States) Energy Frontier Research Centers (EFRC) (United States).Instead, it is likely that π-stacking of the segregated donors and acceptors within the ribbons results in delocalization of the charges following photoexcitation, allowing them to overcome Coulombic attraction and generate free charge carriers. These results suggest that the free charge carrier yield in this system is not limited by a bound charge transfer (CT) state or promoted by a vibronically hot CT state. In addition, this yield is independent of temperature, free energy of reaction, and the ZnP-PDI distance in the covalent dyad. Elongating the side chains on ZnP and PDI in 1b enhances the order of the films, but does not result in an increase in free charge carrier yield. radical ion pairs form in Following photoexcitation of the ordered ribbons, ZnP + Orthogonal attachment of polar and nonpolar side-chains to a zinc porphyrin-perylenediimide dyad (ZnP-PDI, 1a) is shown herein to result in self-assembly of ordered supramolecular ribbons in which the ZnP and PDI molecules form segregated $$π$$-stacked columns.
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