Benchmarking break-junction techniques: electric and thermoelectric characterization of naphthalenophanes

Break-junction techniques provide the possibility to study electric and thermoelectric properties of single-molecule junctions in great detail. These techniques rely on the same principle of controllably breaking metallic contacts in order to create single-molecule junctions, whilst keeping track of the junction's conductance. Here, we compare...

Platinum contacts for 9-atom-wide armchair graphene nanoribbons

Creating a good contact between electrodes and graphene nanoribbons (GNRs) has been a long-standing challenge in searching for the next GNR-based nanoelectronics. This quest requires the controlled fabrication of sub-20 nm metallic gaps, a clean GNR transfer minimizing damage and organic contamination during the device fabrication, as well as...

Implementation of SNS thermometers into molecular devices for cryogenic thermoelectric experiments

Thermocurrent flowing through a single-molecule device contains valuable information about the quantum properties of the molecular structure and, in particular, on its electronic and phononic excitation spectra and entropy. Furthermore, accessing the thermoelectric heat-to-charge conversion efficiency experimentally can help to select...

Mechanical compression in cofacial porphyrin cyclophane pincers

Intra- and intermolecular interactions are dominating chemical processes, and their concerted interplay enables complex nonequilibrium states like life. While the responsible basic forces are typically investigated spectroscopically, a conductance measurement to probe and control these interactions in a single molecule far out of equilibrium is...

Thermoelectricity in single-molecule devices

As the miniaturization of electronics continuously progresses, harvesting and generating thermoelectric energy with high efficiency become a key concept to integrate. Theoretical studies suggest that single-molecule devices are ideal candidates for thermoelectric devices with unprecedentedly high efficiencies. Such advantage is achieved by...

Magnetic-Field Universality of the Kondo Effect Revealed by Thermocurrent Spectroscopy

Probing the universal low-temperature magnetic-field scaling of Kondo-correlated quantum dots via electrical conductance has proved to be experimentally challenging. Here, we show how to probe this in nonlinear thermocurrent spectroscopy applied to a molecular quantum dot in the Kondo regime. Our results demonstrate that the bias-dependent...

Mechanical conductance tunability of a porphyrin-cyclophane single-molecule junction

The possibility to study quantum interference phenomena at ambient conditions is an appealing feature of molecular electronics. By connecting two porphyrins in a cofacial cyclophane, we create an attractive platform for mechanically controlling electric transport through the intramolecular extent of π-orbital overlap of the porphyrins facing...

Substitution Pattern Controlled Quantum Interference in [2.2]Paracyclophane-Based Single-Molecule Junctions

Quantum interference (QI) within a single-molecule junction has become an essential yet powerful concept to integrate for designing molecular electronic devices.1 Recently we have investigated the correlation between substitution pattern, conductance and mechanosensitivity in [2.2]paracyclophane(PCP)-based single-molecule junction via the...

Complete mapping of the thermoelectric properties of a single molecule

Theoretical studies suggest that mastering the thermocurrent through single molecules can lead to thermoelectric energy harvesters with unprecedentedly high efficiencies.^1–6 This can be achieved by engineering molecule length,⁷ optimizing the tunnel coupling strength of molecules via chemical anchor groups⁸ or...

Substitution Pattern Controlled Quantum Interference in [2.2]Paracyclophane-Based Single-Molecule Junctions

Quantum interference (QI) of electron waves passing through a single-molecule junction provides a powerful means to influence its electrical properties. Here, we investigate the correlation between substitution pattern, conductance, and mechanosensitivity in [2.2]paracyclophane (PCP)-based molecular wires in a mechanically controlled break...

Controlling the Entropy of a Single-Molecule Junction

Single molecules are nanoscale thermodynamic systems with few degrees of freedom. Thus, the knowledge of their entropy can reveal the presence of microscopic electron transfer dynamics that are difficult to observe otherwise. Here, we apply thermocurrent spectroscopy to directly measure the entropy of a single free radical molecule in a...

Synthesis and Transport Studies of a Cofacial Porphyrin Cyclophane

Porphyrin cyclophane 1, consisting of two rigidly fixed but still movable cofacial porphyrins and exposing acetate-masked thiols in opposed directions of the macrocycle, is designed, synthesized, and characterized. The functional cyclophane 1, as pioneer of mechanosensitive 3D materials, forms stable single-molecule junctions in a...

Quantum interference-induced conductance variation in mechanosensitive single-molecule junction

A great interest of molecular electronics comes from its change in electronic structure through external stimuli, which provides functionality at the single-molecule level. Mechanically-controlled break junction (MCBJ) is a great tool for characterizing molecular properties and their response to different stimuli including light, solvent and...

Thickness-Dependent Refractive Index of 1L, 2L, and 3L MoS ₂ , MoSe ₂ , WS ₂ , and WSe ₂

An interesting aspect of 2D materials is the change of their electronic structure with the reduction of thickness. Molybdenum and tungsten-based transition metal dichalcogenides form an important family of 2D materials, whose members show a thickness-dependent bandgap and strong light–matter interaction. In this work, the experimental...

Mass measurement of graphene using quartz crystal microbalances

Current wafer-scale fabrication methods for graphene-based electronics and sensors involve the transfer of single-layer graphene by a support polymer. This often leaves some polymer residue on the graphene, which can strongly impact its electronic, thermal, and mechanical resonance properties. To assess the cleanliness of graphene fabrication...

Large Conductance Variations in a Mechanosensitive Single-Molecule Junction

An appealing feature of molecular electronics is the possibility of inducing changes in the orbital structure through external stimuli. This can provide functionality on the single-molecule level that can be employed for sensing or switching purposes if the associated conductance changes are sizable upon application of the stimuli. Here, we...