Pentacene-based organic thin film transistors for ammonia sensing

Hsiao-Wen Zan*, Wu Wei Tsai, Yen Ren Lo, Yu Mei Wu, Yuh-Shyong Yang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


Non-invasive ammonia sensors are attractive alternatives for the diagnoses of a variety of chronic diseases such as liver cirrhosis and renal failure. A low cost pentacene-based organic thin film transistor (OTFT) fabricated by a novel and simple process was demonstrated to be highly sensitive and specific for ammonia gas. Various measurement parameters that reflected OTFT device characteristics for ammonia detection were investigated. Significant variations of the turn-on current, intrinsic mobility, and threshold voltage (V th were observed while subthreshold swing (S.S.) was almost unchanged to the alteration of ammonia concentration. The OTFT device detected 0.5 ∼ 5 ppm concentration ammonia gas at room temperature, which is in the critical range that can distinguish between healthy person and paticents with liver cirrhosis and renal failure. The sensitivity of the device was further enhanced following a simple UV irradiation treatment to modify the functional groups on poly(methyl methacrylate) (PMMA) dielectric layer. Possible interference for ammonia detection such as humidity effect and selectivity among nitrogen, alcohol, carbon dioxide, acetone, methane and ammonia were also examined. We concluded that the proposed pentacene-based OTFT is a promising device for the future application in non-invasive medical diagnoses.

Original languageEnglish
Article number5722012
Pages (from-to)594-601
Number of pages8
JournalIEEE Sensors Journal
Issue number3
StatePublished - 20 Feb 2012


  • Ammonia sensor
  • non-invasive
  • OTFT
  • pentacene


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