Abstract
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.