First-principles simulations of exciton diffusion in organic semiconductors

Zhang, Xu; Li, Zi; Lü, Gang

doi:10.1103/physrevb.84.235208

Cited by 60 publications

(94 citation statements)

References 43 publications

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“…Nonadiabatic quantum molecular dynamics (NAQMD) simulation [7][8][9][10][11][12] shows that this increases the charge-transfer rate at the Rub/C 60 interface by an order-ofmagnitude compared to that at Tc/C 60 .…”

Section: Introductionmentioning

confidence: 99%

Enhanced charge transfer by phenyl groups at a rubrene/C60 interface

Mou

Ohmura

Hattori

et al. 2012

The Journal of Chemical Physics

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A crossover in anisotropic nanomechanochemistry of van der Waals crystals Applied Physics Letters 107, 231903 (2015) Exciton dynamics at an interface between an electron donor, rubrene, and a C 60 acceptor is studied by nonadiabatic quantum molecular dynamics simulation. Simulation results reveal an essential role of the phenyl groups in rubrene in increasing the charge-transfer rate by an order-of-magnitude. The atomistic mechanism of the enhanced charge transfer is found to be the amplification of aromatic breathing modes by the phenyl groups, which causes large fluctuations of electronic excitation energies. These findings provide insight into molecular structure design for efficient solar cells, while explaining recent experimental observations.

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Section: Introductionmentioning

confidence: 99%

Enhanced charge transfer by phenyl groups at a rubrene/C60 interface

Mou

Ohmura

Hattori

et al. 2012

The Journal of Chemical Physics

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“…those deriving from a molecular dynamics simulation [5][6][7][8][9][10][11][12][13] or representing the interaction between chromophores in an amorphous system. [14][15][16][17][18][19][20] To perform these large scale simulations efficiently, to rationalize the observed properties and to design new materials it is important to identify the main components of the excitonic coupling and assess their relative importance.…”

Section: Introductionmentioning

confidence: 99%

Importance and Nature of Short-Range Excitonic Interactions in Light Harvesting Complexes and Organic Semiconductors

Fornari

Rowe

Padula

et al. 2017

J. Chem. Theory Comput.

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Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:"This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Chemical Theory and Computation. copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work http://pubs.acs.org/page/policy/articlesonrequest/index.html ." A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL above for details on accessing the published version and note that access may require a subscription. AbstractThe singlet excitonic coupling between many pairs of chromophores is evaluated in three different Light Harvesting Complexes (LHCs) and two organic semiconductors (amorphous and crystalline). This large database of structures is used to assess the relative importance of short-range (exchange, overlap, orbital) and long-range (Coulombic) excitonic coupling. We find that Mulliken atomic transition charges can introduce systematic errors in the Coulombic coupling and that the dipole-dipole interaction fails to capture the true Coulombic coupling even at intermolecular distances of up to 50 Å. The non-Coulombic short range contribution to the excitonic coupling is found to represent up to ~70% of the total value for molecules in close contact, while, as expected, it is found to be negligible for dimers not in close contact. For the face-to-face dimers considered here, the sign of the short range interaction is found to correlate with the sign of the Coulombic coupling, i.e. reinforcing it when it is already strong. We conclude that for molecules in van der Waals contact the inclusion of short range effects is essential for a quantitative description of the exciton dynamics.

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“…15 In addition, lower excitation energies usually lead to stronger couplings between the ground state and excited states, and thus shorter lifetimes as found in simulations. 29,30 The computed lowest excitation energies are listed in Table II and the trend in the excitation energies is consistent with the exciton lifetimes shown in Table I.…”

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confidence: 86%

“…Exciton diffusion in the disordered molecular domain is modeled by our recently developed first-principles method, 15 which includes a range-separated hybrid exchange-correlation functional [16][17][18] for determining exciton energies and manybody wave-functions, along with a non-adiabatic molecular dynamics [19][20][21] for evaluating exciton transition rates. Exciton diffusion in a crystalline structure is determined by a welldeveloped approach combining F€ orster model [22][23][24][25] with firstprinciples calculations of exciton coupling and reorganization energies.…”

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confidence: 99%

Understanding molecular structure dependence of exciton diffusion in conjugated small molecules

Zhang

Woellner

et al. 2014

Applied Physics Letters

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First-principles simulations are carried out to understand molecular structure dependence of exciton diffusion in a series of small conjugated molecules arranged in a disordered, crystalline, and blend structure. Exciton diffusion length (LD), lifetime, and diffusivity in four diketopyrrolopyrrole derivatives are calculated and the results compare very well with experimental values. The correlation between exciton diffusion and molecular structure is examined in detail. In the disordered molecule structure, a longer backbone length leads to a shorter exciton lifetime and a higher exciton diffusivity, but it does not change LD substantially. Removal of the end alkyl chains or the extra branch on the side alkyl chains reduces LD. In the crystalline structure, exciton diffusion exhibits a strong anisotropy whose origin can be elucidated from the intermolecular transition density interaction point of view. In the blend structure, LD increases with the crystalline ratios, which are estimated and consistent with the experimental results.

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First-principles simulations of exciton diffusion in organic semiconductors

Cited by 60 publications

References 43 publications

Enhanced charge transfer by phenyl groups at a rubrene/C60 interface

Enhanced charge transfer by phenyl groups at a rubrene/C60 interface

Importance and Nature of Short-Range Excitonic Interactions in Light Harvesting Complexes and Organic Semiconductors

Understanding molecular structure dependence of exciton diffusion in conjugated small molecules

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