Ethanol gas sensors based on copper phthalocyanine thin-film transistors

A bottom contact copper phthalocyanine (CuPc) based organic thin film transistor (OTFT) was fabricated in this paper. CuPc thin film acting both as gas sensing layer and the active layer was formed by vacuum evaporation and was characterized by scanning electron microscope(SEM). The results show that the film is highly ordered and has a polycrystalline morphology. The current-voltage characteristics of the OTFT were also investigated. The drain-source current in the saturation region would changed when the OTFT was exposed to ethanol vapor compared to that under an exposure to nitrogen gas at room temperature. It is observed that the CuPc based OTFT sensor has high sensitivity and quick response time to ethanol. It indicates that the drain-source current can be considered as a key parameter to monitor chemical species. Such OTFT devices are promising to act as a novel class of chemical sensors.