Electronic transport properties of indolyl spirooxazine/merooxazine-based light-driven molecular switch: The effect of amino/nitro substituents

By applying non-equilibrium Green's function formulation combined with first-principles density functional theory, we explore the electronic transport properties of indolinospironaphthoxazine (SO)/indolinomeronaphthoxazine (MO). The results indicate that the MO allows a far larger current than the SO. The substituent group can cause shifts of the energy levels. Higher ON/OFF current ratio can be obtained if either amino or nitro substituent is placed at the position of naphthalene moiety. Our results suggest that such molecular wires can generally display switching function and the efficiency can be increased by adding certain substituent groups to the molecules.