Controlling visible light driven photoconductivity in self-assembled perylene bisimide structures

Walsh, J. R., Lee, J. R., Draper, E. R., , King, S. M., Jäckel, F., Zwijnenburg, M. A., Adams, D. J. and Cowan, A. J. (2016) Controlling visible light driven photoconductivity in self-assembled perylene bisimide structures. Journal of Physical Chemistry C, 120(33), pp. 18479-18486. (doi: 10.1021/acs.jpcc.6b06222)

Abstract

Alanine-functionalized perylene bisimides (PBI-A) are promising photoconductive materials. PBI-A self-assembles at high concentrations (mM) into highly ordered wormlike structures that are suitable for charge transport. However, we previously reported that the photoconductive properties of dried films of PBI-A did not correlate with the electronic absorption spectra as activity was only observed under UV light. Using transient absorption spectroscopy, we now demonstrate that charge separation can occur within these PBI-A structures in water under visible light. The lack of charge separation in the films is shown by DFT calculations to be due to a large ion-pair energy in the dried samples which is due to both the low dielectric environment and the change in the site of hole-localization upon drying. However, visible light photoconductivity can be induced in dried PBI-A films through the addition of methanol vapor, a suitable electron donor. The extension of PBI-A film activity into the visible region demonstrates that this class of self-assembled PBI-A structures may be of use in a heterojunction system when coupled to a suitable electron donor.

• Item Type: Articles
• Additional Information: J.J.W. and E.R.D. acknowledge the EPSRC for financial support. J.R.L. acknowledges the School of Physics (University of Liverpool) for a GTA studentship. A.J.C., D.J.A., and M.A.Z. thank the EPSRC for fellowships (EP/K006851/1, EP/ L021978/1, and EP/I004424/1 respectively). The Laser Loan Pool of the Central Laser Facility (CLF), part of the UK Science and Technology Facilities Council (STFC), is thanked for the loan of equipment through EP/G03088X/1. Experiments at the ISIS Pulsed Neutron and Muon Source were supported by a beam-time allocation from the STFC (Computational time on ARCHER, the U.K.’s national highperformance computing service (via our membership of the U..K’s HPC Materials Chemistry Consortium, which is funded by EPSRC grant EP/L000202/1), and the EPSRC National Service for Computational Chemistry Software is gratefully acknowledged. This work benefitted from the SasView software, originally developed by the DANSE project under NSF award DMR-0520547.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Draper, Emily and Adams, Dave
• Authors: Walsh, J. R., Lee, J. R., Draper, E. R.,, King, S. M., Jäckel, F., Zwijnenburg, M. A., Adams, D. J., and Cowan, A. J.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Physical Chemistry C
• Publisher: American Chemical Society
• ISSN: 1932-7447
• ISSN (Online): 1932-7455
• Published Online: 01 August 2016
• Copyright Holders: Copyright © 2016 American Chemical Society
• First Published: First published in Journal of Physical Chemistry C 120(33):18479–18486
• Publisher Policy: Reproduced under a creative commons license