Geometry of Molecular Motions in Dye Monolayers at Various Coverages
Author(s)
Vaissier, Valerie; Van Voorhis, Troy
DownloadVaissier17JPCC.pdf (1.716Mb)
PUBLISHER_POLICY
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
Molecular motion in monolayers is thought to influence the kinetics of charge transport and recombination in systems such as dye-sensitized solar cells (DSSCs). In this work, we use ab initio molecular dynamics to evaluate the geometry and time scale of such molecular motion in a D102 monolayer. D102, a dye that is routinely used in DSSCs, contains two chemical groups, namely, indoline and triphenylethylene, that are also present in many other dyes. We find that, at low surface coverage, the dye molecule exhibits two main tilting axes around which it heavily distorts within 10 ps. Further, the two benzene rings in the triphenylethylene group rotate with a 3–4-ps period. We observe that these large-amplitude movements are suppressed at full coverage, meaning that dye molecules in a monolayer are locked into place and undergo only minor conformational changes. Our observations indicate that, counterintuitively, charge diffusion across dye monolayers might be faster in the parts of the system that are characterized by a lower surface coverage. Because charge transport in dye monolayers has been shown to accelerate recombination kinetics in DSSCs, these results provide the basis for a new understanding of the electronic properties of sensitized systems and device efficiency.
Date issued
2017-05Department
Massachusetts Institute of Technology. Department of ChemistryJournal
Journal of Physical Chemistry C
Publisher
American Chemical Society (ACS)
Citation
Vaissier, Valérie, and Troy Van Voorhis. “Geometry of Molecular Motions in Dye Monolayers at Various Coverages.” The Journal of Physical Chemistry C 121, 23 (June 2017): 12562–12568 © 2017 American Chemical Society
Version: Author's final manuscript
ISSN
1932-7447
1932-7455