Response enhancement mechanism of NO2 gas sensing in ultrathin pentacene field-effect transistors

• Monolayer pentacene FETs being built for achievement of high sensitivity gas sensors.
• Monolayer FETs applying to NO2 is precedently enhanced for three orders of magnitude.
• Good results attributed to 2D electrical transport characters and strong NO2 affinity.

By optimization of structural and physical–chemical properties at a precision level of molecules, organic sensing devices seek to realize the state of the art in monolayer based device applications. In our work, pentacene ultrathin film transistor has been integrated into the implement of a gas sensor based on an increase in its mobility and a shift of its threshold voltage. A limit of detection of pentacene monolayer field-effect transistor was found to be at sub ppm level when it is applied for detection of NO2. Compared with a thick layer sensor device, the pentacene monolayer NO2 sensor has boosted up sensing response with three orders of magnitude. An enhancement of high selectivity and response mechanism can be understood with a reasonable description emphasizing on the 2D transport characters and a series of gauzy interplay for monolayer pentacene film with NO2 analyte.

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