Sensitivity, Selectivity, and Analyte Interaction Effects of Noncovalent Dopants on Graphene Sensors

Experimental work on graphene-based gas sensors has shown that their chemiresistive response is strongly affected by noncovalent doping. Recent computational research has investigated the noncovalent doping of spin-polarized chemiresistive 6-zGNR (zigzag graphene nanoribbon) gas sensors in the detection of explosive molecules. The zGNRs were treated with both p-type (iodine) and n-type (potassium) adatoms. Bond-current analysis showed sharp differences in the sensor response for active (iodine) and passive (potassium) dopants. Active dopants take a direct role in the current transmission process, producing a three-body interaction among the dopant, GNR, and analyte. Passive dopants instead regulate the charge density in the GNR, via electron donation or withdrawal, producing an effective two-body sensing interaction between the GNR and the analyte. Expanded application of doped sensing arrays, to include multiple dopants, may offer opportunities to construct high-dimensional, low-power nanoscale sensors tailored to detect specific analytes.