Outstanding Performance of Transition-Metal-Decorated Single-Layer Graphene-like BCN Nanosheets for Disease Biomarker Detection in Human Breath

In the present work, we report highly sensitive and selective nanosensors constructed with metal-decorated graphene-like BCN employing nonequilibrium Green's function (NEGF) formalism combined by density functional theory (DFT) toward multiple inorganic and sulfur-containing gas molecules (NO, NO, NH, CO, CO, HS, and SO) as disease biomarkers from human breath. Monolayer sheets of pristine BCN and Pd-decorated BCN were evaluated for their gas adsorption properties, electronic property changes, sensitivity, and selectivity toward disease biomarkers. The pristine BCN nanosheets exhibited sharp drops in the bandgap when interacted with gases such as NO while barely affected by other gases. However, the nanosecond recovery time and low adsorption energies limit the gas sensing applications of the pristine BCN sheet. On the other hand, the Pd-decorated BCN-based sensor underwent a semiconductor to metal transition upon the adsorption of NO gas molecules. The conductance change of the sensor's material in terms of - characteristics revealed that the Pd-decorated BCN sensor is highly sensitive (98.6-134%) and selective (12.3-74.4 times) toward NO gas molecules with a recovery time of 270 s under UV radiation at 498 K while weakly interacting with interfering gases in exhaled breath such as CO and HO. The gas adsorption behavior suggests that metal-decorated BCN sensors are excellent candidates for analyzing pulmonary disease and cardiovascular biomarkers, among other ailments of the stomach, kidney, and intestine.