Field-Effect Transistor Based On Percolation Network Of Reduced Graphene Oxide For Real-Time Ppb-Level Detection Of Lead Ions In Water

Real-time lead ion monitoring for drinking water is in an urgent demand, due to the high biotoxicity of lead. We fabricated a reduced graphene oxide (rGO) percolation network based field-effect transistor (FET) by using an easy and scalable micromolding-in-capillary method for lead ion detection in water. The percolation theory analysis elucidates that the required GO mass concentration for a 2D continuum connection converges at a predictable value. Guided by the theoretical analysis, the prepared rGO network was constructed with 1-4 layers of rGO flakes and exhibits comparable electrical properties with single-layer rGO devices. A thin Al(2)O(3)layer was deposited on the device to isolate the analyte from the FET device. With the specific L-Glutathione reduced (GSH) probe, the sensor can reach a limit of detection (LOD) in ppb-level to lead ions. In addition, good selectivity and the high sensing response to Pb(2+)concentrations around 15 ppb (maximum contaminant level of lead for drinking water, US Environmental Protection Agency) suggest our sensor holds great potential for lead ion monitoring in drinking water.