Towards understanding the doping mechanism of organic semiconductors by Lewis acids

Brett Yurash, David Xi Cao, Viktor V. Brus, Dirk Leifert, Ming Wang, Alana Dixon, Martin Seifrid, Ahmed E. Mansour, Dominique Lungwitz, Tuo Liu, Peter J. Santiago, Kenneth R. Graham, Norbert Koch, Guillermo C. Bazan, Thuc Quyen Nguyen

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Precise doping of organic semiconductors allows control over the conductivity of these materials, an essential parameter in electronic applications. Although Lewis acids have recently shown promise as dopants for solution-processed polymers, their doping mechanism is not yet fully understood. In this study, we found that B(C6F5)3 is a superior dopant to the other Lewis acids investigated (BF3, BBr3 and AlCl3). Experiments indicate that Lewis acid–base adduct formation with polymers inhibits the doping process. Electron–nuclear double-resonance and nuclear magnetic resonance experiments, together with density functional theory, show that p-type doping occurs by generation of a water–Lewis acid complex with substantial Brønsted acidity, followed by protonation of the polymer backbone and electron transfer from a neutral chain segment to a positively charged, protonated one. This study provides insight into a potential path for protonic acid doping and shows how trace levels of water can transform Lewis acids into powerful Brønsted acids.

Original languageEnglish
Pages (from-to)1327-1334
Number of pages8
JournalNature Materials
Volume18
Issue number12
DOIs
Publication statusPublished - Dec 1 2019
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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