Detection of arsenic impurities using tetracene-based molecular junctions

Major advances in molecular diagnostics have fueled the search for nanosensors that can detect anomalies in their early stages of development. In this research work, we have investigated a tetracene molecule bridged between gold electrodes in a device configured for sensor application in medical diagnostics. Density functional theory (DFT) and non-equilibrium Green’s (NEGF) functions have been utilized to study the feasibility of tetracene molecular junctions for detecting the presence of arsenic and tracing its concentration. In this context, transmission spectra, molecular-projected self-consistent Hamiltonian (MPSH), current–voltage curve, conductance trends, and HOMO–LUMO gap (HLG) at different operating voltages are determined. Notably, during exposure of the molecular junction to varying concentrations of arsenic, substantial changes are detected in the electron transport properties. Both the conductance and current of the molecular junction escalates with the increase in impurity of the arsenic atoms, thus proving that tetracene is a suitable candidate to be explored as a nanosensor.