A single molecule rectifier with strong push-pull coupling.
We theoretically investigate the electronic charge transport in a molecular system composed of a donor group (dinitrobenzene) coupled to an acceptor group (dihydrophenazine) via a polyenic chain (unsaturated carbon bridge). Ab initio calculations based on the Hartree-Fock approximations are performed to investigate the distribution of electron states over the molecule in the presence of an external electric field. For small bridge lengths (n=0-3) we find a homogeneous distribution of the frontier molecular orbitals, while for n>3 a strong localization of the lowest unoccupied molecular orbital is found. The localized orbitals in between the donor and acceptor groups act as conduction channels when an external electric field is applied. We also calculate the rectification behavior of this system by evaluating the charge accumulated in the donor and acceptor groups as a function of the external electric field. Finally, we propose a phenomenological model based on nonequilibrium Green's function to rationalize the ab initio findings.
Saraiva-Souza
Aldilene
A
Departamento de Física, Universidade Federal do Ceará, Ceará, Brazil.
Macedo de Souza
Fabricio
F
Aleixo
Vicente F P
VF
Girão
Eduardo Costa
EC
Filho
Josué Mendes
JM
Meunier
Vincent
V
Sumpter
Bobby G
BG
Souza Filho
Antonio Gomes
AG
Del Nero
Jordan
J