One of the main goals of organic and molecular electronics is to relate the performance and electronic function of devices to the chemical structure and intermolecular interactions of the organic component inside them, which can take the form of an organic thin film, a self-assembled monolayer or a single molecule. This goal is difficult to achieve because organic and molecular electronic devices are complex physical-organic systems that consist of at least two electrodes, an organic component and two (different) organic/inorganic interfaces. Singling out the contribution of each of these components remains challenging. So far, strong π-π interactions have mainly been considered for the rational design and optimization of the performances of organic electronic devices, and weaker intermolecular interactions have largely been ignored. Here, we show experimentally that subtle changes in the intermolecular van der Waals interactions in the active component of a molecular diode dramatically impact the performance of the device. In particular, we observe an odd-even effect as the number of alkyl units is varied in a ferrocene-alkanethiolate self-assembled monolayer. As a result of a more favourable van der Waals interaction, junctions made from an odd number of alkyl units have a lower packing energy (by ∼0.4-0.6 kcal mol(-1)), rectify currents 10 times more efficiently, give a 10% higher yield in working devices, and can be made two to three times more reproducibly than junctions made from an even number of alkyl units.

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High-entropy alloys (HEAs) can have either high strength or high ductility, and a simultaneous achievement of both still constitutes a tough challenge. The inferior castability and compositional segregation of HEAs are also obstacles for their technological applications. To tackle these problems, here we proposed a novel strategy to design HEAs using the eutectic alloy concept, i.e. to achieve a microstructure composed of alternating soft fcc and hard bcc phases. As a manifestation of this concept, an AlCoCrFeNi2.1 (atomic portion) eutectic high-entropy alloy (EHEA) was designed. The as-cast EHEA possessed a fine lamellar fcc/B2 microstructure, and showed an unprecedented combination of high tensile ductility and high fracture strength at room temperature. The excellent mechanical properties could be kept up to 700°C. This new alloy design strategy can be readily adapted to large-scale industrial production of HEAs with simultaneous high fracture strength and high ductility.

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The reproducibility of the electrical characteristics of molecular junctions has been notoriously low. This paper describes a method to construct tunnel junctions based on self‐assembled monolayers (SAMs) by forming reversible electrical contacts to SAMs using top‐electrodes of a non‐Newtonian liquid‐metal (GaOx/EGaIn) stabilized in a microfluidic‐based device. A single top‐electrode can be used to form up to 15–25 junctions. This method generates SAM‐based junctions with highly reproducible electrical characteristics in terms of precision (widths of distributions) and replicability (closeness to a reference value). The reason is that this method, unlike other approaches that rely on cross‐bar or nano/micropore configurations, does not require patterning of the bottom‐electrodes and is compatible with ultra‐flat template‐stripped (TS) surfaces. This compatibly with non‐patterned electrodes is important for three reasons. i) No edges of the electrodes are present at which SAMs cannot pack well. ii) Patterning requires photoresist that may contaminate the electrode and complicate SAM formation. iii) TS‐surfaces contain large grains, have low rms values, and can be obtained and used (in ordinary laboratory conditions) within a few seconds to minimize contamination. The junctions have very good electrical stability (2500 current‐voltage cycles and retained currents for 27 h), and can be fabricated with good yields (≈78%).