Long-range exciton diffusion in molecular non-fullerene acceptors

Yuliar Firdaus, Vincent M. Le Corre, Safakath Karuthedath, Wenlan Liu, Anastasia Markina, Wentao Huang, Shirsopratim Chattopadhyay, Masrur Morshed Nahid, Mohamad I. Nugraha, Yuanbao Lin, Akmaral Seitkhan, Aniruddha Basu, Weimin Zhang, Iain McCulloch, Harald Ade, John G. Labram, Frédéric Laquai, Denis Andrienko, L. Jan Anton Koster, Thomas D. Anthopoulos

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Abstract The short exciton diffusion length associated with most classical organic semiconductors used in organic photovoltaics (5-20 nm) imposes severe limits on the maximum size of the donor and acceptor domains within the photoactive layer of the cell. Identifying materials that are able to transport excitons over longer distances can help advancing our understanding and lead to solar cells with higher efficiency. Here, we measure the exciton diffusion length in a wide range of nonfullerene acceptor molecules using two different experimental techniques based on photocurrent and ultrafast spectroscopy measurements. The acceptors exhibit balanced ambipolar charge transport and surprisingly long exciton diffusion lengths in the range of 20 to 47 nm. With the aid of quantum-chemical calculations, we are able to rationalize the exciton dynamics and draw basic chemical design rules, particularly on the importance of the end-group substituent on the crystal packing of nonfullerene acceptors.
Original languageEnglish (US)
JournalNature Communications
Volume11
Issue number1
DOIs
StatePublished - Oct 15 2020

Bibliographical note

KAUST Repository Item: Exported on 2020-11-03
Acknowledged KAUST grant number(s): Award No. OSR-2018-CARF/CCF-3079.
Acknowledgements: This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2018-CARF/CCF-3079. The work by V.M.L.C. is supported by a grant from STW/NWO (VIDI 13476). This is a publication by the FOM Focus Group “Next Generation Organic Photovoltaics”, participating in the Dutch Institute for Fundamental Energy Research (DIFFER). D.A. acknowledges funding from the BMBF grants InterPhase and MESOMERIE (FKZ 13N13661, FKZ 13N13656) and the European Union Horizon 2020 research and innovation program “Widening materials models” under Grant Agreement
No. 646259 (MOSTOPHOS). D.A. also acknowledges the KAUST PSE Division for hosting his sabbatical in the framework of the Division’s Visiting Faculty program. A.M. acknowledges postdoctoral support of the Alexander von Humboldt Foundation. H.A.and M.M.N. acknowledge the support from the University of North Carolina General Administration Research Opportunity Initiative (ROI) and U.S. Department of Energy (DE-AC02-05CH11231) for X-ray data acquisition at beamline 7.3.3 at the Advanced Light Source (ALS) in Berkeley National Laboratory, California.

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