Very low degree of energetic disorder as the origin of high mobility in an n-channel polymer semiconductor

Mario Caironi*, Matt Bird, Daniele Fazzi, Zhihua Chen, Riccardo Di Pietro, Christopher Newman, Antonio Facchetti, Henning Sirringhaus

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

167 Scopus citations

Abstract

Charge transport is investigated in high-mobility n-channel organic field-effect transistors (OFETs) based on poly{[N,N′-bis(2-octyldodecyl)- naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2, 2′-bithiophene)} (P(NDI2OD-T2), Polyera ActivInk™ N2200) with variable-temperature electrical measurements and charge-modulation spectroscopy. Results indicate an unusually uniform energetic landscape of sites for charge-carrier transport along the channel of the transistor as the main reason for the observed high-electron mobility. Consistent with a lateral field-independent transport at temperatures down to 10 K, the reorganization energy is proposed to play an important role in determining the activation energy for the mobility. Quantum chemical calculations, which show an efficient electronic coupling between adjacent units and a reorganization energy of a few hundred meV, are consistent with these findings. The origin of high electron mobility in an n-channel polymer is investigated by means of charge-modulation spectroscopy and variable-temperature electrical measurements on field-effect transistors. A uniform energetic landscape for the carriers emerges as the main reason for the efficient charge transport. Consistently, relatively low reorganization energies and high couplings are calculated.

Original languageEnglish (US)
Pages (from-to)3371-3381
Number of pages11
JournalAdvanced Functional Materials
Volume21
Issue number17
DOIs
StatePublished - Sep 9 2011

Keywords

  • charge transport
  • conjugated polymers
  • organic electronics
  • organic field-effect transistors
  • organic semiconductors

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics

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