A flexible transparent graphene/metal-organic framework complex hybrid chemical sensor for highly sensitive ethanol detection

High-performance flexible and transparent chemical sensors are key to achieving wearable electronics. Graphene with high transmittance and electrical properties is a suitable material for flexible and transparent chemical sensors. However, graphene has low detectivity to chemical substances. Here, we report hybrid chemical sensors fabricated by introducing a highly flat and smooth metal-organic framework (MOF) on graphene. The graphene chemical sensors functionalized with MOF on SiO2/Si wafer exhibit 22 times higher sensitivity of 6.07 mu A ppm-1 in detecting ethanol than that of pristine graphene transistors of 0.28 mu A ppm-1 and a low detection limit of 1 ppm. Furthermore, a flexible transparent 7 x 7 chemical sensor array exhibits great driving stability after the bending cycles of 105 at a bending radius of 1.0 mm and shows sensitivity of 0.11 mu A ppm-1. Our findings demonstrate an efficient way to improve the chemical sensing ability of graphene for application in wearable chemical sensors.image Chemical sensors based on metal-organic framework (MOF) synthesized by layer-by-layer method and graphene for detecting ethanol are reported. The sensitivity of MOF-functionalized graphene transistors is enhanced by 22 times than that of pristine graphene transistors owing to charge transfer from MOF to graphene. These sensors show highly flexible and transparent characteristics, making them promising candidates for use in soft electronics.image