Impact of Electrode Density of States on Transport through Pyridine-Linked Single Molecule Junctions

Adak, Olgun; Korytár, Richard; Joe, Andrew Y.; Evers, Ferdinand; Venkataraman, Latha

doi:10.1021/acs.nanolett.5b01195

Cited by 70 publications

(106 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, a transition between different molecular conformations can be probed with greater control than in the traditional STM-BJ, which uses a constant tip withdrawal rate. 11 Application of such procedures can provide more information about the molecular junction than that in a constant bias junction. 6 In a related set of STM-BJ modifications, modulation of the bias voltage within the STM-BJ is accomplished, and it is performed by sweeping the bias voltage while the position of the STM tip is stopped during the withdrawal in STM-BJ.…”

Section: Introductionmentioning

confidence: 99%

A scanning tunneling microscope break junction method with continuous bias modulation

2015

View full text Add to dashboard Cite

Single molecule conductance measurements on 1,8-octanedithiol were performed using the scanning tunneling microscope break junction method with an externally controlled modulation of the bias voltage. Application of an AC voltage is shown to improve the signal to noise ratio of low current (low conductance) measurements as compared to the DC bias method. The experimental results show that the current response of the molecule(s) trapped in the junction and the solvent media to the bias modulation can be qualitatively different. A model RC circuit which accommodates both the molecule and the solvent is proposed to analyze the data and extract a conductance for the molecule.

show abstract

Section: Introductionmentioning

confidence: 99%

A scanning tunneling microscope break junction method with continuous bias modulation

2015

View full text Add to dashboard Cite

show abstract

“…We used a recently developed a.c. technique 25 , described briefly in the Methods and in Supplementary Section II, to determine the location of the conducting orbital (ε) and its coupling (Γ) to the Au electrodes for TDO4 in PC and TCB. The values obtained were then checked against zero-bias self-energy corrected density functional theory (DFT + Σ) calculations 23,26 .…”

mentioning

confidence: 99%

Single-molecule diodes with high rectification ratios through environmental control

et al. 2015

Self Cite

View full text Add to dashboard Cite

Molecular electronics aims to miniaturize electronic devices by using subnanometre-scale active components. A single-molecule diode, a circuit element that directs current flow, was first proposed more than 40 years ago and consisted of an asymmetric molecule comprising a donor-bridge-acceptor architecture to mimic a semiconductor p-n junction. Several single-molecule diodes have since been realized in junctions featuring asymmetric molecular backbones, molecule-electrode linkers or electrode materials. Despite these advances, molecular diodes have had limited potential for applications due to their low conductance, low rectification ratios, extreme sensitivity to the junction structure and high operating voltages. Here, we demonstrate a powerful approach to induce current rectification in symmetric single-molecule junctions using two electrodes of the same metal, but breaking symmetry by exposing considerably different electrode areas to an ionic solution. This allows us to control the junction's electrostatic environment in an asymmetric fashion by simply changing the bias polarity. With this method, we reliably and reproducibly achieve rectification ratios in excess of 200 at voltages as low as 370 mV using a symmetric oligomer of thiophene-1,1-dioxide. By taking advantage of the changes in the junction environment induced by the presence of an ionic solution, this method provides a general route for tuning nonlinear nanoscale device phenomena, which could potentially be applied in systems beyond single-molecule junctions.

show abstract

“…3,4 For many systems investigated thus far, charge transport occurs via coherent tunneling and therefore, can be described by a transmission function detailing the energy-dependent probability that an incident electron or hole tunnels through the barrier presented by the junction. 5 Several techniques have emerged to experimentally assess energy-level alignment at the metal−molecule interface in single-molecule junctions, including thermopower measurements, 6−8 alternating current (AC) techniques, 9 mapping of current−voltage curves, 10 and gating. 11 However, these methods have been unable to provide a detailed map of the transmission landscape and have instead only provided limited insight into the transmission function.…”

mentioning

confidence: 99%

Mapping the Transmission Functions of Single-Molecule Junctions

Capozzi¹,

Low²,

Xia

et al. 2016

Nano Lett.

Self Cite

View full text Add to dashboard Cite

Charge transport phenomena in single-molecule junctions are often dominated by tunneling, with a transmission function dictating the probability that electrons or holes tunnel through the junction. Here, we present a new and simple technique for measuring the transmission functions of molecular junctions in the coherent tunneling limit, over an energy range of 1.5 eV around the Fermi energy. We create molecular junctions in an ionic environment with electrodes having different exposed areas, which results in the formation of electric double layers of dissimilar density on the two electrodes. This allows us to electrostatically shift the molecular resonance relative to the junction Fermi levels in a manner that depends on the sign of the applied bias, enabling us to map out the junction's transmission function and determine the dominant orbital for charge transport in the molecular junction. We demonstrate this technique using two groups of molecules: one group having molecular resonance energies relatively far from EF and one group having molecular resonance energies within the accessible bias window. Our results compare well with previous electrochemical gating data and with transmission functions computed from first principles. Furthermore, with the second group of molecules, we are able to examine the behavior of a molecular junction as a resonance shifts into the bias window. This work provides a new, experimentally simple route for exploring the fundamentals of charge transport at the nanoscale.

show abstract

Impact of Electrode Density of States on Transport through Pyridine-Linked Single Molecule Junctions

Cited by 70 publications

References 57 publications

A scanning tunneling microscope break junction method with continuous bias modulation

A scanning tunneling microscope break junction method with continuous bias modulation

Single-molecule diodes with high rectification ratios through environmental control

Mapping the Transmission Functions of Single-Molecule Junctions

Contact Info

Product

Resources

About