Spiro-OMeTAD single crystals: Remarkably enhanced charge-carrier transport via mesoscale ordering

Dong Shi, X. Qin, Yuan Li, Yao He, Cheng Zhong, Jun Pan, H. Dong, Wei Xu, T. Li, W. Hu, Jean-Luc Bredas, Osman Bakr

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117 Scopus citations


We report the crystal structure and hole-transport mechanism in spiro-OMeTAD [2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene], the dominant hole-transporting material in perovskite and solid-state dye-sensitized solar cells. Despite spiro-OMeTAD’s paramount role in such devices, its crystal structure was unknown because of highly disordered solution-processed films; the hole-transport pathways remained ill-defined and the charge carrier mobilities were low, posing a major bottleneck for advancing cell efficiencies. We devised an antisolvent crystallization strategy to grow single crystals of spiro-OMeTAD, which allowed us to experimentally elucidate its molecular packing and transport properties. Electronic structure calculations enabled us to map spiro-OMeTAD’s intermolecular charge-hopping pathways. Promisingly, single-crystal mobilities were found to exceed their thin-film counterparts by three orders of magnitude. Our findings underscore mesoscale ordering as a key strategy to achieving breakthroughs in hole-transport material engineering of solar cells.
Original languageEnglish (US)
Pages (from-to)e1501491
JournalScience advances
Issue number4
StatePublished - Apr 15 2016

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: O.M.B. and J.-L.B acknowledges the financial support of King Abdullah University of
Science and Technology Grant URF/1/2268-01-01. J.-L.B. also acknowledges support from ONR
Global through Grant N62909-15-1-2003. H.D. thanks the National Natural Science Foundation
of China (91433115). Author contributions: D.S. conceived the idea. O.M.B. crafted the overall
experimental plan and directed the research. D.S. optimized the crystallization. D.S. and W.X.
performed the confocal optical microscope imaging. D.S. and Y.H. performed single-crystal
XRD and data analysis. D.S., X.Q., H.D., T.L., and W.H. planned and performed the mobility
measurements and analyzed the data. Y.L., C.Z., and J.-L.B. planned and performed the theoretical
calculations. Y.L., C.Z., and J.-L.B. analyzed the data of the theoretical part. J.P. assisted D.S. in the
experiments. D.S., Y.L., J.-L.B., and O.M.B. wrote the manuscript. All authors discussed and commented
on the manuscript. Competing interests: The authors declare that they have no
competing interests. Data and materials availability: All data needed to evaluate the conclusions
in the paper are present in the paper and/or the Supplementary Materials. Additional data related
to this paper may be requested from the authors.


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