Star-shaped self-assembly of an organic thin film transistor sensor in the presence of Cu2+ and CN- ions

Mohan Ramesh, Yuan Ruei You, Muthaiah Shellaiah, Meng Chyi Wu, Hong-Cheu Lin*, Chih Wei Chu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


In this study we developed organic thin film transistors (OTFTs) for the sensing of metal ions and anions through the self-assembly of a pentacene/Schiff base pyrene derivative. Our bilayer OTFTs displayed attractive device parameters: an electron mobility (μ) of 0.12 cm2 V -1 s-1, a threshold voltage (V th) of 22.20 V, and a five-orders-of-magnitude on/off ratio. This device was sensitive toward Cu2+ among 13 metal cations and toward CN- among nine anions, as measured through changes in the values of Vth and Ioff in the presence of Cu2+ cations and a change in the value of Isat in the presence of CN- anions. We observed selectivity toward both of these ions in mixed ion solutions, with sensitivity over different concentrations (from 20 to 350 μM for Cu2+; from 100 to 350 μM for CN-) as well as in sea water. The pyrene derivative self-assembled through pyrene-pyrene * coordination in the presence of Cu2+ ions; the rods of the pyrene derivative broke into smaller pieces upon formation of benzoxazole rings in the presence of CN- ions, as confirmed using atomic force microscopy and fourier transform attenuated total reflection spectroscopy.

Original languageEnglish
Pages (from-to)582-589
Number of pages8
JournalOrganic Electronics
Issue number2
StatePublished - 1 Jan 2014


  • Cyanide anion
  • Metal ion
  • Pyrene
  • Self-assembly
  • Sensor
  • Thin film transistor


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