We perform transport measurements on proximitized, ballistic,bilayergraphene Josephson junctions (BGJJs) in the intermediate-to-long junctionregime (L > ξ). We measure the device’sdifferential resistance as a function of bias current and gate voltagefor a range of different temperatures. The extracted critical current IC follows an exponential trend with temperature:exp(−kBT/δE). Here δE = ℏνF/2πL: an expectedtrend for intermediate-to-long junctions. From δE, we determine the Fermi velocity of the bilayer graphene, whichis found to increase with gate voltage. Simultaneously, we show thecarrier density dependence of δE, which isattributed to the quadratic dispersion of bilayer graphene. This isin contrast to single layer graphene Josephson junctions, where δE and the Fermi velocity are independent of the carrierdensity. The carrier density dependence in BGJJs allows for additionaltuning parameters in graphene-based Josephson junction devices.

The unique properties of graphene make it an ideal material for electrochemical studies, particularly of the electrochemical double-layer. However, experimental studies generally require depositing graphene on substrates like gold, that may affect the electronic structure of the electrode and thus the ions adsorption properties. This study explores the impact of gold substrates on graphene electrochemical behavior using molecular dynamics. Two systems were compared: graphene on gold (Gr@Au) and standalone graphene (Gr), with ionic liquid ([EMIM][TFSI]) as the electrolyte. The model accounts for the different metallic behavior of graphene and gold under the various applied potentials. Despite a similar electrolyte structure, the interfacial capacitance is affected, which can be attributed to different charge distributions within the electrode. The variations of the van der Waals and Coulomb energies also show some differences in the presence of gold, in particular for low potentials.

Two-dimensional (2D)metal-halide perovskites have promising characteristicsfor optoelectronic applications. By incorporating Mn2+ ionsinto the perovskite structure, improved photoluminescence quantumyield can be achieved. This has been attributed to the formation ofdefect states that act as efficient recombination centers. Here, wemake use of transient photoluminescence microscopy to characterizeimportant material parameters of Mn2+-doped 2D perovskiteswith different doping levels. From these measurements, we visualizethe importance of exciton transport as an intermediate step in theexcitation of Mn2+. We model the spatiotemporal dynamicsof the excited states to extract the diffusion constant and the transferrate of the excitations to the Mn dopant sites. Interestingly, fromthese models, we find that the average distance an exciton needs totravel before transferring to a Mn site is significantly larger thanexpected from the Mn concentration obtained from elemental analysis.These insights are critical from a device design perspective.

Acidic oxygen evolution reaction (OER) has long been the bottleneck of proton exchange membrane water electrolysis. Ru- and Ir-based oxides are currently state-of-the-art electrocatalysts for acidic OER, but their high cost limits their widespread application. Co3O4 is a promising alternative, yet the performance requires further improvement. Crystal facet engineering can effectively regulate the kinetics of surface electrochemistry and thus enhance the OER performance. However, the facet-dependent OER activity and corrosion behavior of Co3O4 have not been thoroughly studied. In this study, we systematically investigated the OER performance and crystal facet dependency of Co3O4. The results demonstrate that Co3O4 with mixed {111} and {110} facets exhibits better OER activity and stability than Co3O4 with {111} or {100} facets. The surface Co3+ species are responsible for the high OER activity, but its transformation to CoO2 is also the root cause of the dissolution, leading to an activity-stability trade-off effect. The possible approach to addressing this issue would be to increase the Co3+ contents by nanostructure engineering. To further improve the performance, Ru is introduced to the best-performing Co3O4. The resulting Co3O4/RuO2 heterostructure exhibits an overpotential of 257 mV at 10 mA cm-2 and can stably catalyze the OER for 100 h.

Herein, we present a strategy for the controlled assembly of single-walled carbon nanotube (SWCNT) linear junctions mediated by DNA as a functional linker. We demonstrate this by employing SWCNTs of two different chiralities via the specific design of DNA sequences and chiral selection. Streptavidin and AuNP labeling of the SWCNT sidewalls demonstrate the presence of two different chirality within each individual CNT-DNA-CNT junction. These one-dimensional nanohybrids were further organized from solution to devices. The approach we developed is of general applicability for the assembly of functional nanohybrids based on carbon nanotubes toward functional applications.

Given that daily exposure to nanoparticles is now unavoidable, there are concerns that nanoparticles have unexpected biological effects due to their small size. Here, we examined the biodistribution of silver nanoparticles, which are the most frequently used nanoparticles owing to their antibacterial activity, with a diameter of 10 nm (nAg10) to the male genital tract, and the effects of paternal treatment with nAg10 on fetal development. Male Slc:ICR male mice were orally treated with nAg10 for 14 consecutive days. Inductively coupled plasma mass spectrometry analysis detected silver in the blood and testis of male mice, but no general toxicological effects were induced. Moreover, there were no significant changes in fetal development when these treated male mice were mated with nontreated female mice. This implies that although orally ingested nAg10 is distributed to the male genital tract, it does not affect fetal development under the present treatment conditions.

While the continuous development of advanced bioprinting technologies is under fervent study, enhancing the regenerative potential of hydrogel-based constructs using external stimuli for wound dressing has yet to be tackled. Fibroblasts play a significant role in wound healing and tissue implants at different stages, including extracellular matrix production, collagen synthesis, and wound and tissue remodeling. This study explores the synergistic interplay between photothermal activity and nanomaterial-mediated cell proliferation. The use of different graphene-based materials (GBM) in the development of photoactive bioinks is investigated. In particular, we report the creation of a skin-inspired dressing for wound healing and regenerative medicine. Three distinct GBM, namely, graphene oxide (GO), reduced graphene oxide (rGO), and graphene platelets (GP), were rigorously characterized, and their photothermal capabilities were elucidated. Our investigations revealed that rGO exhibited the highest photothermal efficiency and antibacterial properties when irradiated, even at a concentration as low as 0.05 mg/mL, without compromising human fibroblast viability. Alginate-based bioinks alongside human fibroblasts were employed for the bioprinting with rGO. The scaffold did not affect the survival of fibroblasts for 3 days after bioprinting, as cell viability was not affected. Remarkably, the inclusion of rGO did not compromise the printability of the hydrogel, ensuring the successful fabrication of complex constructs. Furthermore, the presence of rGO in the final scaffold continued to provide the benefits of photothermal antimicrobial therapy without detrimentally affecting fibroblast growth. This outcome underscores the potential of rGO-enhanced hydrogels in tissue engineering and regenerative medicine applications. Our findings hold promise for developing game-changer strategies in 4D bioprinting to create smart and functional tissue constructs with high fibroblast proliferation and promising therapeutic capabilities in drug delivery and bactericidal skin-inspired dressings.

Single-molecule experiments offer a unique means to probe molecular properties of individual molecules-yet they rest upon the successful control of background noise and irrelevant signals. In single-molecule transport studies, large amounts of data that probe a wide range of physical and chemical behaviors are often generated. However, due to the stochasticity of these experiments, a substantial fraction of the data may consist of blank traces where no molecular signal is evident. One-class (OC) classification is a machine learning technique to identify a specific class in a data set that potentially consists of a wide variety of classes. Here, we examine the utility of two different types of OC classification models on four diverse data sets from three different laboratories. Two of these data sets were measured at cryogenic temperatures and two at room temperature. By training the models solely on traces from a blank experiment, we demonstrate the efficacy of OC classification as a powerful and reliable method for filtering out blank traces from a molecular experiment in all four data sets. On a labeled 4,4'-bipyridine data set measured at 4.2 K, we achieve an accuracy of 96.9 ± 0.3 and an area under the receiver operating characteristic curve of 99.5 ± 0.3 as validated over a fivefold cross-validation. Given the wide range of physical and chemical properties that can be probed in single-molecule experiments, the successful application of OC classification to filter out blank traces is a major step forward in our ability to understand and manipulate molecular properties.

Nanotechnology is vital to many current industries, including electronics, energy, textiles, agriculture, and theranostics. Understanding the chemical mechanisms of nanomaterial synthesis has contributed to the tunability of their unique properties, although studies frequently overlook the potential impact of impurities. Impurities can show adverse effects, clouding the interpretation of results or limiting the practical utility of the nanomaterial. On the other hand, as successful doping has demonstrated, the intentional introduction of impurities can be a powerful tool for enhancing the properties of a nanomaterial. This Review examines the complex role of impurities, unintentionally or intentionally added, during nanoscale synthesis and their effects on the performance and usefulness of the most common classes of nanomaterials: nanocarbons, noble metal and metal oxide nanoparticles, semiconductor quantum dots, thermoelectrics, and perovskites.

Niobium pentoxide (Nb2O5) is apromisingnegative electrode for sodium ion batteries (SIBs). By engineeringthe morphology and crystallinity of nanochanneled niobium oxides (NCNOs),the kinetic behavior and charge storage mechanism of Nb2O5 electrodes were investigated. Amorphous and crystallineNCNO samples were made by modulating anodization conditions (20–40V and 140–180 °C) to synthesize nanostructures of varyingpore sizes and wall thicknesses with identical chemical composition.The electrochemical energy storage properties of the NCNOs were studied,with the amorphous samples showing better overall rate performancethan the crystalline samples. The enhanced rate performance of theamorphous samples is attributed to the higher capacitive contributionsand Na-ion diffusivity analyzed from cyclic voltammetry (CV) and thegalvanostatic intermittent titration technique (GITT). It was foundthat the amorphous samples with smaller wall thicknesses facilitatedimproved kinetics. Among samples with similar pore size and wall thickness,the difference in their power performance stems from the crystallinityeffect, which plays a more significant role in the resulting kineticsof the materials for Na-ion batteries.