Organic field-effect transistor gas sensor based on GO/PMMA hybrid dielectric for the enhancement of sensitivity and selectivity to ammonia

Organic field-effect transistor (OFET) based ammonia gas sensors were fabricated by incorporating a simple solution processed hybrid dielectric, which consisting of poly(methyl methacrylate) (PMMA) and Graphene Oxide (GO) sheets. By carefully optimizing the proportion of GO sheets in the dielectric, a remarkable improvement of sensing performance was obtained when exposed to various NH3 concentrations. Compared with those with pure PMMA dielectric, the sensitivity of OFET sensors with hybrid dielectric had two orders of magnitude enhancement from 1.4% to 30%. The GO/PMMA hybrid dielectric based OFET also shows good selectivity for NH3 against H2S, SO2, and NO2. By analyzing the hybrid dielectric and the 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) film through utilizing fourier transform infrared spectroscopy, X-ray diffraction and atomic force microscope, the enhanced sensing performance was attributed to the preferable interaction between functional groups on GO sheets and NH(3 )gas molecules. The improved sensing performance by the combination of GO and PMMA also suggests the possibility of proper dielectric functionality engineering for the further fabrication of OFET based gas sensors with high performance.