Thin-film transistor as a probe to study carrier transport in amorphous organic semiconductors

Shu Kong SO*, Wing H. Choi, Chi H. Cheung

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

5 Citations (Scopus)


We describe how to use the thin-film transistor (TFT) technique to quantify carrier transport of amorphous organic semiconductors relevant to organic electronic devices. We have chosen several amorphous materials, including arylamine compounds, 4,4'-N,N'-dicarbazole-biphenyl (CBP), and a phosphorescent dye molecule [Ir(ppy)3] for investigations. Generally, the field effect (FE) mobility was found to be about one order of magnitude smaller than that obtained from an independent time-of-flight (TOF) technique. For N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) and N,N'-Bis(3-methylphenyl)-N,N'-bis(phenyl)-9,9-spirobifluorene (spiro-TPD), the FE mobilities were found to be 1.7×10-5 and 1.3 ×10 -5cm2/Vs, respectively. Temperature-dependent measurements were carried out to study the FE mobility. It was found that the energetic disorder increased in the neighborhood of a gate dielectric layer. This factor is one of the origins causing the discrepancy between TFT and TOF mobilities. We also examined how the hole transport of CBP is affected by Ir(ppy)3 when it is doped into CBP.

Original languageEnglish
Article number011011
JournalJournal of Photonics for Energy
Issue number1
Publication statusPublished - 2011

Scopus Subject Areas

  • Atomic and Molecular Physics, and Optics
  • Renewable Energy, Sustainability and the Environment

User-Defined Keywords

  • Hole transports, 4,4'-N,N'-dicarbazole-biphenyl (CBP)
  • Organic light-emitting diodes (OLEDs)
  • Thin-film transistors
  • Tris(2-phenylpyridine) iridum [Ir(ppy)]


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