Highly Sensitive Chemical-Vapor Sensor Based on Thin-Film Organic Field-Effect Transistors with Benzothiadiazole-Fused-Tetrathiafulvalene

摘要

The synthesis of a new tetrathiafulvalene derivative with an electron-withdrawing benzothiadiazole moiety and its use in thin-film organic field-effect transistors (OFETs) are reported. Compared to reported OFETs with other TTF derivatives, a high hole mobility up to 0.73 cm~2 V~(-1) s~(-1) low off-current and high on/off ratio up to 10s are demonstrated. In addition, the developed OFETs show fast responsiveness toward chemical vapors of DECP (diethyl chlorophosphate) or POCI_3 which are simulants of phosphate-based nerve agents. In contrast to previously reported OFET-based sensors, off-current is used as the output signal, which increases quickly upon exposure to either DECP or POCI_3 vapors. High sensitivity is demonstrated toward DECP and POCI_3 vapors, with concentrations as low as 10 ppb being detected. These OFETs are also responsive to TNT vapor. The sensing mechanisms for the new type of OFET are discussed.