Moiré Exciton Polaron Engineering via twisted hBN.

Twisted hexagonal boron nitride (thBN) exhibits ferroelectricity due to moiré superlattices with AB/BA domains. These domains possess electric dipoles, leading to a periodic electrostatic potential that can be imprinted onto other materials placed in its proximity. Here we demonstrate the remote imprinting of moiré patterns from thBN onto monolayer MoSe and investigate the changes in the exciton properties.

Overestimation of Operational Stability in Polymer-Based Organic Field-Effect Transistors Caused by Contact Resistance.

The bias-stress effects of bottom-gate top-contact polymer-based organic field-effect transistors (OFETs) with different channel lengths (50-500 μm) were evaluated by repeating cycles of prolonged on-state gate-bias application and transfer characteristics measurements in the linear regime. The thicknesses of poly(didodecylquaterthiophene--didodecylbithiazole) active layers were 26 and 37 nm. All OFETs exhibited nonlinear (nonideal) transfer characteristics with a maximum transconductance within the gate-source voltage sweep range.

Moiré magnetism in CrBr multilayers emerging from differential strain.

Interfaces between twisted 2D materials host a wealth of physical phenomena originating from the long-scale periodicity associated with the resulting moiré structure. Besides twisting, an alternative route to create structures with comparably long-or even longer-periodicities is inducing a differential strain between adjacent layers in a van der Waals (vdW) material. Despite recent theoretical efforts analyzing its benefits, this route has not yet been implemented experimentally.

Anti-hepatocellular carcinoma activities of novel hydrazone derivatives downregulation of interleukin-6.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related morbidity worldwide. Sorafenib is a first-line drug for the treatment of HCC, however, it is reported to cause serious adverse effects and may lead to resistance in many patients. In this study, 20 hydrazone derivatives incorporating triazoles, pyrazolone, pyrrole, pyrrolidine, imidazoline, quinazoline, and oxadiazine moieties were designed, synthesized, and characterized.

Synthesis of Bis(diimino)palladium Nanosheets as Highly Active Electrocatalysts for Hydrogen Evolution.

Development of efficient electrocatalysts for hydrogen evolution reactions (HERs) is necessary to achieve environmentally friendly and sustainable hydrogen production. To reduce cost and to circumvent the scarcity of platinum, the most efficient catalyst for HER, it is essential to develop catalysts using ubiquitous base metals or minimal amounts of precious metals. Bis(diimino)metal (MDI) coordination nanosheets are potential HER catalysts because their electric conductivities, two-dimensionality, and porous structures provide large surface areas and efficient mass and electron transfer.

Magnetic-Electrical Synergetic Control of Non-Volatile States in Bilayer Graphene-CrOCl Heterostructures.

Anti-ferromagnetic insulator chromium oxychloride (CrOCl) has shown peculiar charge transfer and correlation-enhanced emerging properties when interfaced with other van der Waals conductive channels. However, the influence of its spin states to the channel material remains largely unknown. Here, this issue is addressed by directly measuring the density of states in bilayer graphene (BLG) interfaced with CrOCl via a high-precision capacitance measurement technique and a surprising hysteretic behavior in the charging states of the heterostructure is observed.

Engineering Superconducting Contacts Transparent to a Bipolar Graphene.

Graphene's exceptional electronic mobility, gate-tunability, and contact transparency with superconducting materials make it ideal for exploring the superconducting proximity effect. However, the work function difference between graphene and superconductors causes unavoidable doping of graphene near contacts, forming a p-n junction in the hole-doped regime and reducing the contact transparency. This challenges the device implementation that exploits graphene's bipolarity.

Tunable heteroassembly of 2D CoNi LDH and TiC nanosheets with enhanced electrocatalytic activity for oxygen evolution.

The sluggish kinetics of the oxygen evolution reaction (OER) is the bottleneck to developing hydrogen energy based on water electrolysis, which can be significantly improved using high performance catalysts. In this context, CoNi layered double hydroxide (LDH)/TiC heterostructures are obtained using electrostatic attraction of the positively charged LDH and negatively charged TiC nanosheets as the catalyst to optimize the OER performance. Such alternate stacking exhibits good catalytic activity with a lower overpotential and a small Tafel slope, outperforming their individual components.

Geometrically engineered organoid units and their assembly for pre-construction of organ structures.

Regenerative medicine is moving from the nascent to the transitional stage as researchers are actively engaged in creating mini-organs from pluripotent stem cells to construct artificial models of physiological and pathological conditions. Currently, mini-organs can express higher-order functions, but their size is limited to the order of a few millimeters. Therefore, one of the ultimate goals of regenerative medicine, "organ replication and transplantation with organoid," remains a major obstacle.

Detecting and Controlling DNA Translocation through a Nanopore using a van der Waals Heterojunction Diode.

A long-unrealized goal in solid-state nanopore sensing is to achieve out-of-plane electrical sensing and control of DNA during translocation, which is a prerequisite for base-by-base ratcheting that enables DNA sequencing in biological nanopores. Two-dimensional (2D) heterostructures, with their capability to construct out-of-plane electronics with atomic layer precision, are ideal yet unexplored candidates for use as electrical sensing membranes. Here we demonstrate a nanopore architecture using a vertical 2D heterojunction diode consisting of p-type WSe on n-type MoS.

Direct visualization of relativistic quantum scars in graphene quantum dots.

Quantum scars refer to eigenstates with enhanced probability density along unstable classical periodic orbits. First predicted 40 years ago, scars are special eigenstates that counterintuitively defy ergodicity in quantum systems whose classical counterpart is chaotic. Despite the importance and long history of scars, their direct visualization in quantum systems remains an open field.

Stress-strain curve predictions by crystal plasticity simulations and machine learning.

The stress-strain curve (SSC) prediction for additively manufactured as-build metal materials with laser powder bed fusion (LPBF) is a lengthy and tedious process. It involves the sophisticated representative volume element (RVE) reconstruction of complex experimental microstructures for subsequent state-of-the-art crystal plasticity simulations with hyperparameter tunings in the appropriate physical model. However, even with a well-fitted model, simulations with different RVEs or temperatures, for example, are too time-consuming and computationally intensive.

Spin transport of a doped Mott insulator in moiré heterostructures.

Moiré superlattices of semiconducting transition metal dichalcogenide heterobilayers are model systems for investigating strongly correlated electronic phenomena. Specifically, WSe/WS moiré superlattices have emerged as a quantum simulator for the two-dimensional extended Hubbard model. Experimental studies of charge transport have revealed correlated Mott insulator and generalized Wigner crystal states, but spin transport of the moiré heterostructure has not yet been sufficiently explored.

Non-Adiabatic Excited-State Time-Dependent (TD) Molecular Dynamics Simulation of Nickel-Atom Aided Photolysis of Methane to Produce a Hydrogen Molecule.

Methane photolysis is a very important initiation reaction from the perspective of hydrogen production for alternative energy applications. In our recent work, we demonstrated using our recently developed novel method, non-adiabatic excited-state time-dependent GW (TDGW) molecular dynamics (MD), how the decomposition reaction of methane into a methyl radical and a hydrogen atom was captured accurately via the time-tracing of all quasiparticle levels. However, this process requires a large amount of photoabsorption energy (PAE ∼10.

Superior P-Type Switching in InSe Nanosheets for Complementary Multifunctional Systems.

van der Waals (vdW) indium selenide (InSe) is receiving attention for its exceptional electron mobility and moderate band gap, enabling various applications. However, the intrinsic -type behavior of InSe has restricted its use predominantly to -type devices, constraining its application in complementary integrated microsystems. Here, we show superior ambipolar InSe transistors with vdW bottom contacts, achieving impressive -type on/off current ratios greater than 10 and Schottky barrier heights approaching the ideal Schottky-Mott limit.

Double-Layered Electrospun Nanofiber Filter for the Simultaneous Removal of Urea and Ammonium from Blood.

A major challenge in the development of wearable artificial kidneys (WAKs) lies in the efficient removal of urea, which is found at an extremely high concentration in the blood of patients with chronic kidney disease (CKD). Urease is an enzyme that hydrolyzes urea. While it can efficiently remove urea, toxic ammonium is produced as a byproduct.

Effective disruption of cancer cell membranes by photodynamic therapy with cell membrane-adhesive photosensitizer.

Photodynamic therapy (PDT) is a noninvasive cancer treatment modality that involves the administration of photosensitizers and light irradiation. Previously, we established a polycation-containing hematoporphyrin (aHP) formulation that demonstrated superior antitumor efficacy , than the original hematoporphyrin (HP). In this study, we investigated underlining mechanisms of the high antitumor effect of aHP using cell experiments.

Element-specific ultrafast lattice dynamics in FePt nanoparticles.

Light-matter interaction at the nanoscale in magnetic alloys and heterostructures is a topic of intense research in view of potential applications in high-density magnetic recording. While the element-specific dynamics of electron spins is directly accessible to resonant x-ray pulses with femtosecond time structure, the possible element-specific atomic motion remains largely unexplored. We use ultrafast electron diffraction (UED) to probe the temporal evolution of lattice Bragg peaks of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse.

Quantitative theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy.

Theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy (KPFM) measurements has been challenging due to the complexity introduced by tip-induced band bending (TIBB). In this study, we present a method for numerically computing the electrostatic forces in a fully three-dimensional (3D) configuration. Our calculations on a system composed of a metallic tip and GaAs(110) surface revealed deviations from parabolic behavior in the bias dependence of the electrostatic force, which is consistent with previously reported experimental results.

Quasiperiodic Moiré Reconstruction and Modulation of Electronic Properties in Twisted Bilayer Graphene Aligned with Hexagonal Boron Nitride.

Twisted van der Waals systems have emerged as intriguing arenas for exploring exotic strongly correlated and topological physics, with structural reconstruction and strain playing essential roles in determining their electronic properties. In twisted bilayer graphene aligned with hexagonal boron nitride (TBG/h-BN), the interplay between the two sets of moiré patterns from graphene-graphene (G-G) and graphene-h-BN (G-h-BN) interfaces can trigger notable moiré pattern reconstruction (MPR). Here, we present the quasiperiodic MPR in the TBG/h-BN with two similar moiré wavelengths, wherein the MPR results from the incommensurate mismatch between the wavelengths of the G-G and G-h-BN moiré patterns.