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

Dong Shi, Xiang Qin, Yuan Li, Yao He, Cheng Zhong, Jun Pan, Huanli Dong, Wei Xu, Tao Li, Wenping Hu, Jean Luc Brédas, Osman M. Bakr

Research output: Contribution to journalArticlepeer-review

94 Scopus citations

Abstract

We report the crystal structure and hole-transport mechanism in spiro-OMeTAD [2,2' ,7,7' -tetrakis(N,N-di-pmethoxyphenyl- amine)9,9' -spirobifluorene], the dominant hole-transporting material in perovskite and solidstate 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 illdefined 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)
Article numbere1501491
JournalScience Advances
Volume2
Issue number4
DOIs
StatePublished - Apr 2016
Externally publishedYes

ASJC Scopus subject areas

  • General

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