Bias-Driven Conductance Increase with Length in Porphyrin Tapes.
J Am Chem Soc
; 140(40): 12877-12883, 2018 Oct 10.
Article
em En
| MEDLINE
| ID: mdl-30207150
ABSTRACT
A key goal in molecular electronics has been to find molecules that facilitate efficient charge transport over long distances. Normally, molecular wires become less conductive with increasing length. Here, we report a series of fused porphyrin oligomers for which the conductance increases substantially with length by >10-fold at a bias of 0.7 V. This exceptional behavior can be attributed to the rapid decrease of the HOMO-LUMO gap with the length of fused porphyrins. In contrast, for butadiyne-linked porphyrin oligomers with moderate inter-ring coupling, a normal conductance decrease with length is found for all bias voltages explored (±1 V), although the attenuation factor (ß) decreases from ca. 2 nm-1 at low bias to <1 nm-1 at 0.9 V, highlighting that ß is not an intrinsic molecular property. Further theoretical analysis using density functional theory underlines the role of intersite coupling and indicates that this large increase in conductance with length at increasing voltages can be generalized to other molecular oligomers.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Reino Unido