Introducing a Nonvolatile N-Type Dopant Drastically Improves Electron Transport in Polymer and Small-Molecule Organic Transistors

Julianna Panidi, Jaspreet Kainth, Alexandra F. Paterson, Simeng Wang, Leonidas Tsetseris, Abdul Hamid Emwas, Martyn A. McLachlan, Martin Heeney, Thomas D. Anthopoulos

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Molecular doping is a powerful yet challenging technique for enhancing charge transport in organic semiconductors (OSCs). While there is a wealth of research on p-type dopants, work on their n-type counterparts is comparatively limited. Here, reported is the previously unexplored n-dopant (12a,18a)-5,6,12,12a,13,18,18a,19-octahydro-5,6-dimethyl- 13,18[1′,2′]-benzenobisbenzimidazo [1,2-b:2′,1′-d]benzo[i][2.5]benzodiazo-cine potassium triflate adduct (DMBI-BDZC) and its application in organic thin-film transistors (OTFTs). Two different high electron mobility OSCs, namely, the polymer poly[[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8- bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2′-bithiophene)] and a small-molecule naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene)malononitrile groups (NDI-DTYM2) are used to study the effectiveness of DMBI-BDZC as a n-dopant. N-doping of both semiconductors results in OTFTs with improved electron mobility (up to 1.1 cm2 V−1 s−1), reduced threshold voltage and lower contact resistance. The impact of DMBI-BDZC incorporation is particularly evident in the temperature dependence of the electron transport, where a significant reduction in the activation energy due to trap deactivation is observed. Electron paramagnetic resonance measurements support the n-doping activity of DMBI-BDZC in both semiconductors. This finding is corroborated by density functional theory calculations, which highlights ground-state electron transfer as the main doping mechanism. The work highlights DMBI-BDZC as a promising n-type molecular dopant for OSCs and its application in OTFTs, solar cells, photodetectors, and thermoelectrics.

Original languageEnglish
Article number1902784
JournalAdvanced Functional Materials
Volume29
Issue number34
DOIs
StatePublished - Aug 2019

Bibliographical note

Funding Information:
J.P., A.F.P., M.H., and T.D.A acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC) (grant EP/L016702/1) and from the European Research Council (ERC) AMPRO project no. 280221. L.T. acknowledges support for the computational time granted from the Greek Research & Technology Network (GRNET) in the National HPC facility—ARIS—under project pr006055-STEM-2. M.H. acknowledges support from the Royal Society. T.D.A acknowledges financial support from the King Abdullah University of Science and Technology (KAUST).

Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keywords

  • electron transport
  • molecular doping
  • n-type dopant
  • organic semiconductors
  • organic transistor

ASJC Scopus subject areas

  • Chemistry (all)
  • Materials Science (all)
  • Condensed Matter Physics

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