Formaldehyde gas sensor based on pentacene organic thin-film transistor

Formaldehyde (HCHO) gas sensors based on pentacene active layer and low cost poly (merthyl methacrylate) (PMMA) insulator were fabricated with a structure of bottom contact organic thin-film transistor (OTFT). The OTFT sensor not only presented a remarkable response characteristic in the absence and the presence of HCHO gas with different concentrations, but also exhibited a good repeatability for sensing the HCHO gas. Meanwhile, compared to the device operated in nitrogen circumstance, obvious changes in saturation drain-source current (I-DS) and off-state current were observed when the device exposed to HCHO gas. Also the device performance and sensing mechanisms were discussed.