Modulating the exciton dissociation rate by up to more than two orders of magnitude by controlling the alignment of LUMO + 1 in organic photovoltaics

Article English OPEN
Ma, Haibo ; Troisi, Alessandro (2014)
  • Publisher: American Chemical Society
  • Related identifiers: doi: 10.1021/jp5098102
  • Subject: QC | TK
    arxiv: Condensed Matter::Materials Science | Physics::Chemical Physics

Efficient organic solar cells require a high yield of exciton dissociation. Herein we investigate the possibility of having more than one charge-transfer (CT) state below the first optically bright Frenkel exciton state (FE) for common molecular donor (D)/acceptor (A) pairs and the role of the second-lowest CT state (CT2) in the exciton dissociation process. This situation, previously explored only for fullerene acceptors, is shown to be rather common for other D/A pairs. By considering a phenomenological model of a large aggregate, we reveal that the position of CT2 can remarkably modulate the exciton dissociation rate by up to more than two orders of magnitude. Thus, controlling the alignment of CT2 is suggested as a promising rule for designing new D/A heterojunctions.
  • References (41)
    41 references, page 1 of 5

    [1] Bernardo, B.; Cheyns, D.; Verreet, B.; Schaller, R. D.; Rand, B. P.; Giebink, N. C. Delocalization and dielectric screening of charge transfer states in organic photovoltaic cells. Nat. Comm. 2014, 5, 3245.

    [2] Barker, A. J.; Chen, K.; Hodgkiss, J. M. Ultrafast Charge Generation in an Organic Bilayer Film. J. Am. Chem. Soc. 2014, 136, 12018−12026.

    [3] Kaake, L. G.; Zhong, C.; Love, J. A.; Nagao, I.; Bazan, G. C.; Nguyen, T.-Q.; Huang, F.; Cao, Y.; Moses, D.; Heeger, A. J. Ultrafast Charge Generation in an Organic Bilayer Film. J. Phys. Chem. Lett. 2014, 5, 2000-2006.

    [4] Tautz, R.; Da Como, E.; Wiebeler, C.; Soavi, G.; Dumsch, I.; Fröhlich, N.; Grancini, G.; Allard, S.; Scherf, U.; Cerullo, G.; Schumacher, S.; Feldmann, J. Charge Photogeneration in Donor-Acceptor Conjugated Materials: Influence of Excess Excitation Energy and Chain Length. J. Am. Chem. Soc. 2013, 135, 4282-4290.

    [5] Tamura, H.; Burghardt, I. Ultrafast Charge Separation in Organic Photovoltaics Enhanced by Charge Delocalization and Vibronically Hot Exciton Dissociation. J. Am. Chem. Soc. 2013, 135, 16364-16367.

    [6] Borges, Jr. I.; Aquino, A. J. A.; Köhn, A.; Nieman, R.; Hase, W. L.; Chen, L. X.; Lischka, H. Ab Initio Modeling of Excitonic and Charge-Transfer States in Organic Semiconductors: The PTB1/PCBM Low Band Gap System. J. Am. Chem. Soc. 2013, 135, 18252-18255.

    [8] D'Avino, G.; Mothy, S.; Muccioli, L.; Zannoni, C.; Wang, L.; Cornil, J.; Beljonne, D.; Castet, F. Energetics of Electron-Hole Separation at P3HT/PCBM Heterojunctions. J. Phys. Chem. C 2013, 117, 12981-12990.

    [9] Sun, Z.; Stafström, S. Dynamics of exciton dissociation in donor-acceptor polymer heterojunctions. J. Chem. Phys. 2013, 138, 164905.

    [10] Han, L.; Zhong, X.; Liang, W.; Zhao, Y. Energy relaxation and separation of a hot electronhole pair in organic aggregates from a time-dependent wavepacket diffusion method. J. Chem. Phys. 2014, 140, 214107.

    [11] Raos, G.; Casalegno, M.; Idé, J. An Effective Two-Orbital Quantum Chemical Model for Organic Photovoltaic Materials. J. Chem. Theory Comput. 2014, 10, 364-372.

  • Metrics
    views in OpenAIRE
    views in local repository
    downloads in local repository

    The information is available from the following content providers:

    From Number Of Views Number Of Downloads
    Warwick Research Archives Portal Repository - IRUS-UK 0 47
Share - Bookmark