title: Single Molecule Rectification Induced by the Asymmetry of a Single Frontier Orbital.
abstract: A mechanism for electronic rectification under low bias potentials is elucidated for the prototype molecule HS-phenyl-amide-phenyl-SH. We apply density functional theory (DFT) combined with the nonequilibrium Green's function formalism (NEGF), as implemented in the TranSIESTA computational code to calculate transport properties. We find that a single frontier orbital, the closest to the Fermi level, provides the dominant contribution to the overall transmission and determines the current. The asymmetric distribution of electron density in that orbital leads to rectification in charge transport due to its asymmetric response, shifting toward (or away from) the Fermi level under forward (or reverse) applied bias voltage. These findings provide a simple design principle to suppress recombination in molecular assemblies of dye-sensitized solar cells (DSSCs) where interfacial electron transfer is mediated by frontier orbitals with asymmetric character.
authors.affiliation: Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520-8107, United States.|Energy Sciences Institute, Yale University , P.O. Box 27394, West Haven, Connecticut 06516-7394, United States.
authors.forename: Wendu
authors.initials: W
authors.lastname: Ding
authors.affiliation: Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520-8107, United States.|Energy Sciences Institute, Yale University , P.O. Box 27394, West Haven, Connecticut 06516-7394, United States.
authors.forename: Christian F A
authors.initials: CF
authors.lastname: Negre
authors.affiliation: Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520-8107, United States.|Energy Sciences Institute, Yale University , P.O. Box 27394, West Haven, Connecticut 06516-7394, United States.
authors.forename: Leslie
authors.initials: L
authors.lastname: Vogt
authors.affiliation: Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520-8107, United States.|Energy Sciences Institute, Yale University , P.O. Box 27394, West Haven, Connecticut 06516-7394, United States.
authors.forename: Victor S
authors.initials: VS
authors.lastname: Batista