Manipulating I V Characteristics of a Molecular Switch with Chemical Modifications

We present a study of the effects of chemical modifications on the electron transport properties of the azobenzene molecule, which has been proposed as a component of a light-driven molecular switch. This molecule has two stable conformations (cis and trans) in the electronic ground state, with considerable differences in conductance. The electron transport properties were calculated using first-principles methods combining nonequilibrium Green s function techniques with density functional theory. Chemical modifications of the azobenzene consist of incorporation of electron-donating and electron-withdrawing groups in meta and ortho positions with respect to the azo group. The results show that the transport properties in electronic devices at the molecular level can be manipulated, enhanced, or suppressed by a careful consideration of the effects of chemical modification, and such modifications become crucial in optimizing the electron transport properties of chemical structures.