Gas-sensor property of single-molecule device:F_2 adsorbing effect

The single thiolated arylethynylene molecule with 9,10-dihydroanthracene core(denoted as TADHA) possesses pronounced negative differential conductance(NDC) behavior at lower bias regime. The adsorption effects of F_2 molecule on the current and NDC behavior of TADHA molecular junctions are studied by applying non-equilibrium Green's formalism combined with density functional theory. The numerical results show that the F_2 molecule adsorbed on the benzene ring of TADHA molecule near the electrode can dramatically suppresses the current of TADHA molecular junction. When the F_2 molecule adsorbed on the conjugated segment of 9,10-dihydroanthracene core of TADHA molecule, an obviously asymmetric effect on the current curves induces the molecular system showing apparent rectifier behavior. However, the current especially the NDC behavior have been significantly enlarged when F_2 addition reacted with triple bond of TADHA molecule.