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Title: Charge Separation Mechanisms in Ordered Films of Self-Assembled Donor–Acceptor Dyad Ribbons

Abstract

Orthogonal attachment of polar and nonpolar side-chains to a zinc porphyrin-perylenediimide dyad (ZnP-PDI, 1a) is shown to result in self-assembly of ordered supramolecular ribbons in which the ZnP and PDI molecules form segregated π-stacked columns. Following photoexcitation of the ordered ribbons, ZnP+•-PDI–• radical ion pairs form in <200 fs and subsequently produce a 30 ± 3% yield of free charge carriers that live for about 100 μs. 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. In addition, this yield is independent of temperature, free energy of reaction, and the ZnP-PDI distance in the covalent dyad. 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. 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.

Authors:
 [1];  [1];  [1];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1399126
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Applied Materials and Interfaces; Journal Volume: 9; Journal Issue: 39
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Logsdon, Jenna L., Hartnett, Patrick E., Nelson, Jordan N., Harris, Michelle A., Marks, Tobin J., and Wasielewski, Michael R. Charge Separation Mechanisms in Ordered Films of Self-Assembled Donor–Acceptor Dyad Ribbons. United States: N. p., 2017. Web. doi:10.1021/acsami.7b02585.
Logsdon, Jenna L., Hartnett, Patrick E., Nelson, Jordan N., Harris, Michelle A., Marks, Tobin J., & Wasielewski, Michael R. Charge Separation Mechanisms in Ordered Films of Self-Assembled Donor–Acceptor Dyad Ribbons. United States. doi:10.1021/acsami.7b02585.
Logsdon, Jenna L., Hartnett, Patrick E., Nelson, Jordan N., Harris, Michelle A., Marks, Tobin J., and Wasielewski, Michael R. 2017. "Charge Separation Mechanisms in Ordered Films of Self-Assembled Donor–Acceptor Dyad Ribbons". United States. doi:10.1021/acsami.7b02585.
@article{osti_1399126,
title = {Charge Separation Mechanisms in Ordered Films of Self-Assembled Donor–Acceptor Dyad Ribbons},
author = {Logsdon, Jenna L. and Hartnett, Patrick E. and Nelson, Jordan N. and Harris, Michelle A. and Marks, Tobin J. and Wasielewski, Michael R.},
abstractNote = {Orthogonal attachment of polar and nonpolar side-chains to a zinc porphyrin-perylenediimide dyad (ZnP-PDI, 1a) is shown to result in self-assembly of ordered supramolecular ribbons in which the ZnP and PDI molecules form segregated π-stacked columns. Following photoexcitation of the ordered ribbons, ZnP+•-PDI–• radical ion pairs form in <200 fs and subsequently produce a 30 ± 3% yield of free charge carriers that live for about 100 μs. 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. In addition, this yield is independent of temperature, free energy of reaction, and the ZnP-PDI distance in the covalent dyad. 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. 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.},
doi = {10.1021/acsami.7b02585},
journal = {ACS Applied Materials and Interfaces},
number = 39,
volume = 9,
place = {United States},
year = 2017,
month = 4
}