title: Spectroscopy and rectification of three donor-sigma-acceptor compounds, consisting of a one-electron donor (pyrene or ferrocene), a one-electron acceptor (perylenebisimide), and a C19 swallowtail.
abstract: We report spectroscopic characterization and unimolecular rectification (asymmetric electrical conduction) measurements of three donor-sigma-acceptor (D-sigma-A) compounds N-(10-nonadecyl)-N-(1-pyrenylmethyl)perylene-3,4,9,10-bis(dicarboximide) (1), N-(10-nonadecyl)-N-(4-[1-pyrenyl]butyl)perylene-3,4,9,10-bis(dicarboximide) (2), and N-(10-nonadecyl)-N-(2-ferrocenylethyl)perylene-3,4,9,10-bis(dicarboximide) (3). These molecules were arranged as one-molecule thick Langmuir-Blodgett monolayers between Au electrodes. In such an "Au | D-sigma-A | Au" sandwich, molecule 1 is a unimolecular rectifier, with rather small rectification ratios (between 2 and 3 at +/-1 V) that decrease upon cycling. Molecule 2 does not rectify. Molecule 3 rectifies, with a rectification ratio of between 14 and 28 at +/-1 V; the through-film rectification and currents persist, even with scans of +/-2 V, for up to 40 cycles of measurement. Qualitative arguments, based on a two-level rectification mechanism, are consistent with the current asymmetries observed in the monolayers of 1 and 3.
authors.affiliation: Laboratory for Molecular Electronics, Chemistry Department, University of Alabama, Tuscaloosa, Alabama 35487-0336, USA.
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Shumate
authors.forename: Daniell L
authors.initials: DL
authors.lastname: Mattern
authors.forename: Archana
authors.initials: A
authors.lastname: Jaiswal
authors.forename: David A
authors.initials: DA
authors.lastname: Dixon
authors.forename: Tina Renea
authors.initials: TR
authors.lastname: White
authors.forename: James
authors.initials: J
authors.lastname: Burgess
authors.forename: Andrei
authors.initials: A
authors.lastname: Honciuc
authors.forename: Robert M
authors.initials: RM
authors.lastname: Metzger