Building Electronic Devices by Doping Molecular Wires

Organic molecular wires have the potential to become high performance and low cost devices for the semiconductor industry, if we are able to strategically functionalize them. Electron transfer among frontier molecular orbitals and other neighbor orbitals might facilitate molecular wires to become useful semiconductors. For instance, if the Fermi level of the material is moved closer to the valence or conduction bands by doping (adding of charging substituents), transport under an external electric field is enhanced and controllable; these are very important features for electronic devices. We study a few typical hydrocarbon systems from alkanes to oligophenyleneethynylene (OPE) to carbon nanotubes (CNT) and some of their substituted species using precise and first principles techniques of quantum chemistry to get conformational and electronic structures. The structural characterization is followed by our combined Green's function and density functional theory approach to determine the electron transport characteristics of the molecules.