Precision control of single-molecule electrical junctions

Haiss, Wolfgang; Wang, Changsheng; Grace, Iain; Batsanov, Andrei S.; Schiffrin, David J.; Higgins, Simon J.; Bryce, Martin R.; Lambert, Colin J.; Nichols, Richard J.

doi:10.1038/nmat1781

Cited by 303 publications

(367 citation statements)

References 21 publications

Supporting

Mentioning

333

Contrasting

Order By: Relevance

“…However, when OPV3 is tilted a similar I-V curve to that of the elongated junctions is predicted, again because of the better band line-up arising through the reduced bonding at the interface. The latter findings, while in agreement with recent experimental observations of Haiss et al, 12,13 offer a different interpretation of their results for related wires.…”

Section: Introductionsupporting

confidence: 85%

“…This effect has recently been observed experimentally by Haiss et al for a series of "rigid" molecular wires, 12,13 including an oligo-phenylene- ethynylene derivative with three rings ͑OPE3͒, similar to the OPV3. An explanation of this behavior is provided by the zero bias transmission spectra in Fig.…”

Section: Discussionsupporting

confidence: 60%

“…8,[37][38][39][40][41] Unfortunately there is no experimental evidence of this behavior, e.g., recent measurements on related molecular wires have detected an opposite and expected trend, with the conductance increasing as the contact gap is reduced. 12,13 However, it will be demonstrated below that the predicted characteristics of "rigid" molecular wires in stretched junctions might have already been manifested, although indirectly.…”

Section: Discussionmentioning

confidence: 96%

“…In fact, in a typical experimental setup involving a rigid molecular wire, the reduced distance between the contacts usually results in tilting the molecular orientations away from the surface normal. 12,13 Two tilted conformations have been considered, at 15°and 30°away from the normal, with contact gaps reduced by 0.5 and 2.0 Å from the equilibrium, respectively, and the molecular plane perpendicular to the contact surfaces. Both situations are illustrated in Fig.…”

Section: B Wire Compressionmentioning

confidence: 99%

See 3 more Smart Citations

Conductance of a phenylene-vinylene molecular wire: Contact gap and tilt angle dependence

et al. 2010

View full text Add to dashboard Cite

Charge transport through a molecular junction comprising an oligomer of p-phenylene-vinylene between gold contacts has been investigated using density-functional theory and the nonequilibrium Green's function method. The influence of the contact gap geometry on the transport has been studied for elongated and contracted gaps, as well as various molecular conformations. The calculated current-voltage characteristics show an unusual increase in the low bias conductance with the contact separation. In contrast, for compressed junctions the conductance displays only a very weak dependence on both the separation and related molecular conformation. However, if the contraction of the gap between the electrodes is accommodated by tilting the molecule, the conductance will increase with the tilting angle, in line with experimental observations. It is demonstrated that the effect of tilting on transport can be interpreted in a similar way to the case of the stretching the junction with a molecule in an upright position. The lowest conductance was observed for the equilibrium gap geometry. With the dominant transport contribution arising from the system of the frontier junction orbitals, all the predicted increases in the conductance arise simply from the better band alignment between relevant frontier orbitals at the nonequilibrium geometries at the expense of weaker coupling with the contacts.

show abstract

Section: Introductionsupporting

confidence: 85%

Section: Discussionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 96%

Section: B Wire Compressionmentioning

confidence: 99%

See 2 more Smart Citations

Conductance of a phenylene-vinylene molecular wire: Contact gap and tilt angle dependence

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The sample potential was varied between −0.6 V and +0.5 V, with respect to the Pt quasi-reference electrode. The initial tip-to-sample distance s 0 was approximated using the method described previously by Haiss et al 61 ■ RESULTS Cyclic Voltammetry in Ionic Liquid. The redox active molecular bridge 6pTTF6 (Figure 3) exhibits two reversible redox reactions, one of which is in the potential range available also in aqueous electrolytes.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

Single-Molecule Electrochemical Gating in Ionic Liquids

et al. 2012

Self Cite

View full text Add to dashboard Cite

The single-molecular conductance of a redox active molecular bridge has been studied in an electrochemical single-molecule transistor configuration in a room-temperature ionic liquid (RTIL). The redox active pyrrolo-tetrathiafulvalene (pTTF) moiety was attached to gold contacts at both ends through −(CH2)6S– groups, and gating of the redox state was achieved with the electrochemical potential. The water-free, room-temperature, ionic liquid environment enabled both the monocationic and the previously inaccessible dicationic redox states of the pTTF moiety to be studied in the in situ scanning tunneling microscopy (STM) molecular break junction configuration. As the electrode potential is swept to positive potentials through both redox transitions, an ideal switching behavior is observed in which the conductance increases and then decreases as the first redox wave is passed, and then increases and decreases again as the second redox process is passed. This is described as an “off–on–off–on–off” conductance switching behavior. This molecular conductance vs electrochemical potential relation could be modeled well as a sequential two-step charge transfer process with full or partial vibrational relaxation. Using this view, reorganization energies of ∼1.2 eV have been estimated for both the first and second redox transitions for the pTTF bridge in the 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIOTf) ionic liquid environment. By contrast, in aqueous environments, a much smaller reorganization energy of ∼0.4 eV has been obtained for the same molecular bridge. These differences are attributed to the large, outer-sphere reorganization energy for charge transfer across the molecular junction in the RTIL.

show abstract

Metal Complexes and Clusters in Single‐Molecule Electronics

Vezzoli

2021

Encyclopedia of Inorganic and Bioinorganic Chemistry

View full text Add to dashboard Cite

Single‐molecule electronics has evolved significantly in the past two decades. The first studies that focussed on simple, wire‐like organic compounds have been useful to establish the mechanism of charge transport, but the chemical complexity of the molecular component has been rapidly increased to allow the fabrication of functional devices such as switches and transistors. Organometallic compounds feature prominently in molecular electronics because as they offer, for instance, a straightforward way to impart redox activity and to control on the HOMO–LUMO gap, but they can also be used to study and exploit phenomena unique to the nanoscale world, such as quantum interference and Coulomb blockade effects. This article will present progress in the use of mono‐ and polynuclear (cluster) organometallic molecular wires in single‐molecule junctions, highlighting the breakthrough studies that advanced our understanding of nanoscale charge transport phenomena.

show abstract

Precision control of single-molecule electrical junctions

Cited by 303 publications

References 21 publications

Conductance of a phenylene-vinylene molecular wire: Contact gap and tilt angle dependence

Conductance of a phenylene-vinylene molecular wire: Contact gap and tilt angle dependence

Single-Molecule Electrochemical Gating in Ionic Liquids

Metal Complexes and Clusters in Single‐Molecule Electronics

Contact Info

Product

Resources

About