Hall Effect in Polycrystalline Organic Semiconductors: The Effect of Grain Boundaries

Hyun Ho Choi, Alexandra F. Paterson, Michael A. Fusella, Julianna Panidi, Olga Solomeshch, Nir Tessler, Martin Heeney, Kilwon Cho, Thomas D. Anthopoulos, Barry P. Rand, Vitaly Podzorov

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Highly crystalline thin films in organic semiconductors are important for applications in high-performance organic optoelectronics. Here, the effect of grain boundaries on the Hall effect and charge transport properties of organic transistors based on two exemplary benchmark systems is elucidated: (1) solution-processed blends of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) small molecule and indacenodithiophene-benzothiadiazole (C16IDT-BT) conjugated polymer, and (2) large-area vacuum evaporated polycrystalline thin films of rubrene (C42H28). It is discovered that, despite the high field-effect mobilities of up to 6 cm2 V−1 s−1 and the evidence of a delocalized band-like charge transport, the Hall effect in polycrystalline organic transistors is systematically and significantly underdeveloped, with the carrier coherence factor α < 1 (i.e., yields an underestimated Hall mobility and an overestimated carrier density). A model based on capacitively charged grain boundaries explaining this unusual behavior is described. This work significantly advances the understanding of magneto-transport properties of organic semiconductor thin films.

Original languageEnglish (US)
Article number1903617
JournalAdvanced Functional Materials
Volume30
Issue number20
DOIs
StatePublished - May 1 2020

All Science Journal Classification (ASJC) codes

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

Keywords

  • charge transport
  • hall effect
  • mobility
  • organic field-effect transistors (OFETs)
  • organic semiconductors
  • organic thin-film transistors (OTFTs)
  • polycrystalline films

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