Abstract
We show in this work that conjugated π-electron molecular chains can, in quite specific and understood circumstances, become more conductive the longer they get, in contradiction to what would be expected intuitively. The analysis, done in the framework of the source and sink potential method, and supported by detailed transmission calculations, begins by defining "relative transmission," an inherent measure of molecular conduction. This, in turn, for conjugated hydrocarbons, is related to a simple molecular orbital expression - the ratio of secular determinants of a molecule and one where the electrode contacts are deleted - and a valence bond idea, since these secular determinants can alternatively be expressed in terms of Kekulé structures. A plausible argument is given for relating the relative transmission to the weight of the diradical resonance structures in the resonance hybrid for a molecule. Chemical intuition can then be used to tune the conductivity of molecules by "pushing" them towards more or less diradical character. The relationship between relative transmission (which can rise indefinitely) and molecular transmission is carefully analyzed - there is a sweet spot here for engineering molecular devices. These new insights enable the rationalization of a wide variety of experimental and theoretical results for π-conjugated alternant hydrocarbons, especially the striking difference between extended oligophenylenes and related quinoid chains. In this context, oligo-p-phenylene macrocycles emerge as a potential molecular switch.
| Original language | English |
|---|---|
| Article number | 092310 |
| Journal | Journal of Chemical Physics |
| Volume | 146 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Mar 7 2017 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry
Cite this
Enhancing the conductivity of molecular electronic devices. / Stuyver, Thijs; Fias, Stijn; De Proft, Frank; Geerlings, Paul; Tsuji, Yuta; Hoffmann, Roald.
In: Journal of Chemical Physics, Vol. 146, No. 9, 092310, 07.03.2017.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Enhancing the conductivity of molecular electronic devices
AU - Stuyver, Thijs
AU - Fias, Stijn
AU - De Proft, Frank
AU - Geerlings, Paul
AU - Tsuji, Yuta
AU - Hoffmann, Roald
PY - 2017/3/7
Y1 - 2017/3/7
N2 - We show in this work that conjugated π-electron molecular chains can, in quite specific and understood circumstances, become more conductive the longer they get, in contradiction to what would be expected intuitively. The analysis, done in the framework of the source and sink potential method, and supported by detailed transmission calculations, begins by defining "relative transmission," an inherent measure of molecular conduction. This, in turn, for conjugated hydrocarbons, is related to a simple molecular orbital expression - the ratio of secular determinants of a molecule and one where the electrode contacts are deleted - and a valence bond idea, since these secular determinants can alternatively be expressed in terms of Kekulé structures. A plausible argument is given for relating the relative transmission to the weight of the diradical resonance structures in the resonance hybrid for a molecule. Chemical intuition can then be used to tune the conductivity of molecules by "pushing" them towards more or less diradical character. The relationship between relative transmission (which can rise indefinitely) and molecular transmission is carefully analyzed - there is a sweet spot here for engineering molecular devices. These new insights enable the rationalization of a wide variety of experimental and theoretical results for π-conjugated alternant hydrocarbons, especially the striking difference between extended oligophenylenes and related quinoid chains. In this context, oligo-p-phenylene macrocycles emerge as a potential molecular switch.
AB - We show in this work that conjugated π-electron molecular chains can, in quite specific and understood circumstances, become more conductive the longer they get, in contradiction to what would be expected intuitively. The analysis, done in the framework of the source and sink potential method, and supported by detailed transmission calculations, begins by defining "relative transmission," an inherent measure of molecular conduction. This, in turn, for conjugated hydrocarbons, is related to a simple molecular orbital expression - the ratio of secular determinants of a molecule and one where the electrode contacts are deleted - and a valence bond idea, since these secular determinants can alternatively be expressed in terms of Kekulé structures. A plausible argument is given for relating the relative transmission to the weight of the diradical resonance structures in the resonance hybrid for a molecule. Chemical intuition can then be used to tune the conductivity of molecules by "pushing" them towards more or less diradical character. The relationship between relative transmission (which can rise indefinitely) and molecular transmission is carefully analyzed - there is a sweet spot here for engineering molecular devices. These new insights enable the rationalization of a wide variety of experimental and theoretical results for π-conjugated alternant hydrocarbons, especially the striking difference between extended oligophenylenes and related quinoid chains. In this context, oligo-p-phenylene macrocycles emerge as a potential molecular switch.
UR - http://www.scopus.com/inward/record.url?scp=85008895513&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85008895513&partnerID=8YFLogxK
U2 - 10.1063/1.4972992
DO - 10.1063/1.4972992
M3 - Article
VL - 146
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 9
M1 - 092310
ER -