Synthesis and Application of Acrylonitrile Bridged Thieno[3,2-b]Thiophene Derivative for High Performance Organic Field Effect Transistors and H2S Sensor.

To explore the influence of intermolecular interaction force on the performance of OFET-based sensor and to achieve high detection sensitivity and selectivity, a acrylonitrile bridged thieno[3,2-b]thiophene derivative (2Z,2'Z)-3,3'-(2,2'-thieno[3,2-b]thiophene)bis(2-(naphthalen-2-yl)acrylonitrile) (TTBNA) was synthesized as the active organic semiconductor material. The single crystal x-ray diffraction analysis reveals that TTBNA forms ordered lamellar stacking by the π-π stacking interactions, and each molecule presents four hydrogen bonds through C─H…N with adjacent two molecules within the molecular layer. The OFET devices exhibit high mobility of 0.444 cm2V-1s-1 and on/off ratio larger than 107. The OFET-based sensors show high sensitivity and selectivity for H2S detection and the ratio of current change can still maintain over 2.5 % when the gas concentration lower to 10 ppb level, with the relative sensitivity (RS) up to 250 % ppm-1. The excellent sensing characteristics could be caused by the formation of new hydrogen bonding between H2S molecules and N atoms of TTBNA molecules which was confirmed by the theory simulation calculations. This general approach demonstrates that it would be an effective way to improve sensing response capability by introducing variable intermolecular interaction forces in the active simiconductor materials.