Operationally stable perovskite solar modules enabled by vapor-phase fluoride treatment.

The ever-increasing power conversion efficiency of perovskite solar cells has illuminated the future of the photovoltaic industry, but the development of commercial devices is hampered by their poor stability. In this study, we report a scalable stabilization method using vapor-phase fluoride treatment, which achieves 18.1%-efficient solar modules (228 square centimeters) with accelerated aging-projected lifetimes (time to 80% of efficiency remaining) of 43,000 ± 9000 hours under 1-sun illumination at 30°C.

Nontrivial effects of geometric and charge defects on one-dimensional confined water.

Water confined within nanochannels with specific functionalities serves as the foundation for a variety of emerging nanofluidic applications. However, the structure and dynamics of the confined liquid are susceptibly influenced by practically hard-to-avoid defects, yet knowledge of this fact remains largely unexplored. Here, using extensive molecular dynamics simulations, we elucidate the significant influence of geometric and charge defects on one-dimensional confined water.

Exceptionally Fast Separation of Xylene Isomers with Zeolitic Nanotube Array Membranes.

The separation of xylene isomers is of vital importance in chemical industry but remains challenging due to their similar structure and overlapping physiochemical properties. Membrane-based separations using the zeolite MFI, graphene oxide, and metal-organic frameworks have been intensively studied for this application, but the performance is limited by the well-known rule that the filtrate permeance scales inversely with the membrane thickness. We propose a novel membrane design that is capable of breaking this rule, based on an array of recently discovered zeolite nanotubes.

Strain Engineering of Twisted Bilayer Graphene: The Rise of Strain-Twistronics.

The layer-by-layer stacked van der Waals structures (termed vdW hetero/homostructures) offer a new paradigm for materials design-their physical properties can be tuned by the vertical stacking sequence as well as by adding a mechanical twist, stretch, and hydrostatic pressure to the atomic structure. In particular, simple twisting and stacking of two layers of graphene can form a uniform and ordered Moiré superlattice, which can effectively modulate the electrons of graphene layers and lead to the discovery of unconventional superconductivity and strong correlations. However, the twist angle of twisted bilayer graphene (tBLG) is almost unchangeable once the interlayer stacking is determined, while applying mechanical elastic strain provides an alternative way to deeply regulate the electronic structure by controlling the lattice spacing and symmetry.

Cascaded plastic optical fiber based SPR sensor for simultaneous measurement of refractive index and temperature.

A cascaded side-polish plastic optical fiber (POF) and FONTEX optical fiber based surface plasmon resonance (SPR) sensor is proposed for simultaneous measurement of refractive index (RI) and temperature. The side-polish POF and FONTEX optical fiber are connected by using the UV glue in a Teflon plastic tube. The SPR phenomenon can be excited at both of the side-polish region and the FONTEX fiber cladding.

Graphene binding on black phosphorus enables high on/off ratios and mobility.

Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion.

Non-epitaxial growth of highly oriented transition metal dichalcogenides with density-controlled twin boundaries.

Twin boundaries (TBs) in transition metal dichalcogenides (TMDs) constitute distinctive one-dimensional electronic systems, exhibiting intriguing physical and chemical properties that have garnered significant attention in the fields of quantum physics and electrocatalysis. However, the controlled manipulation of TBs in terms of density and specific atomic configurations remains a formidable challenge. In this study, we present a non-epitaxial growth approach that enables the controlled and large-scale fabrication of homogeneous catalytically active TBs in monolayer TMDs on arbitrary substrates.

Growth Instability of 2D Materials on Non-Euclidean Surfaces.

Chemical growth of two-dimensional (2D) materials with controlled morphology is critical to bring their tantalizing properties to fruition. However, the growth must be on a substrate, which involves either intrinsic or intentionally introduced undulation, at a scale significantly larger than the materials thickness. Recent theory and experiments showed that 2D materials grown on a curved feature on substrates can incur a variety of topological defects and grain boundaries.

Mechanism Regulating Self-Intercalation in Layered Materials.

Recent experimental breakthrough demonstrated a powerful synthesis approach for intercalating the van der Waals gap of layered materials to achieve property modulation, thereby opening an avenue for exploring new physics and devising novel applications, but the mechanism governing intercalant assembly patterns and properties remains unclear. Based on extensive structural search and energetics analysis by calculations, we reveal a Sabatier-like principle that dictates spatial arrangement of self-intercalated atoms in transition metal dichalcogenides. We further construct a robust descriptor quantifying that strong intercalant-host interactions favor a monodispersing phase of intercalated atoms that may exhibit ferromagnetism, while weak interactions lead to a trimer phase with attenuated or quenched magnetism, which further evolves into tetramer and hexagonal phases at increasing intercalant density.

Deep-Learning-Enhanced Diffusion Imaging Assay for Resolving Local-Density Effects on Membrane Receptors.

G-protein-coupled receptor (GPCR) density at the cell surface is thought to regulate receptor function. Spatially resolved measurements of local-density effects on GPCRs are needed but technically limited by density heterogeneity and mobility of membrane receptors. We now develop a deep-learning (DL)-enhanced diffusion imaging assay that can measure local-density effects on ligand-receptor interactions in the plasma membrane of live cells.

Harvesting Energy from Atmospheric Water: Grand Challenges in Continuous Electricity Generation.

Atmospheric water is ubiquitous on earth and extensively participates in the natural water cycle through evaporation and condensation. This process involves tremendous energy exchange with the environment, but very little of the energy has so far been harnessed. The recently emerged hydrovoltaic technology, especially moisture-induced electricity, shows great potential in harvesting energy from atmospheric water and gives birth to moisture energy harvesting devices.

Near-Infrared Blinking Carbon Dots Designed for Quantitative Nanoscopy.

Blinking carbon dots (CDs) have attracted attention as a probe for single molecule localization microscopy (SMLM), yet quantitative analysis is limited because of inept blinking and low signal-to-noise ratio (SNR). Here we report the design and synthesis of near-infrared (NIR) blinking CDs with a maximum emission of around 750 nm by weaving a nitrogen-doped aromatic backbone with surplus carboxyl groups on the surface. The NIR-CDs allow conjugation to monovalent antibody fragments for labeling and imaging of cellular receptors as well as afford increases of 52% in SNR and 33% in localization precision over visible CDs.

Simultaneous Measurement of Refractive Index and Temperature Based on SMF-HCF-FCF-HCF-SMF Fiber Structure.

In this research, we proposed and experimentally verified a compact all-fiber sensor that can measure refractive index (RI) and temperature simultaneously. Two segments of hollow-core fiber (HCF) are connected to the two ends of the four-core fiber (FCF) as a beam splitter and a coupler, and then spliced with two sections of single-mode fibers (lead-in and lead-out SMF), respectively. The two hollow-core fibers can excite the higher-order modes of the four-core fiber and recouple the core modes and higher-order modes into the outgoing single-mode fiber, thereby forming inter-mode interference.

Simultaneous Measurement of Magnetic Field and Temperature Utilizing Magnetofluid-Coated SMF-UHCF-SMF Fiber Structure.

We have proposed and experimentally demonstrated a dual-parameter optical fiber sensor for simultaneous measurement of magnetic field and temperature. The sensor is a magnetofluid-coated single-mode fiber (SMF)-U-shaped hollow-core fiber (UHCF)-single-mode fiber (SMF) (SMF-UHCF-SMF) fiber structure. Combined with the intermodal interference and the macro-bending loss of the U-shaped fiber structure, the U-shaped fiber sensor with different bend diameters was investigated.

An analog of Friedel oscillations in nanoconfined water.

Water confined in nanometer-scale crevices and cavities underpins a wide range of fundamental processes, such as capillary flow, ion transport and protein folding. However, how water responds within these confined spaces, with prevalent inhomogeneity built in or caused by impurities, is not well understood. Here, we show theoretically that water confined in one-dimensional nanochannels with localized perturbation exhibits pronounced density oscillations.

Computational Advances of Protein/Neurotransmitter-membrane Interactions Involved in Vesicle Fusion and Neurotransmitter Release.

Vesicle fusion is of crucial importance to neuronal communication at neuron terminals. The exquisite but complex fusion machinery for neurotransmitter release is tightly controlled and regulated by protein/neurotransmitter-membrane interactions. Computational 'microscopies', in particular molecular dynamics simulations and related techniques, have provided notable insight into the physiological process over the past decades, and have made enormous contributions to fields such as neurology, pharmacology and pathophysiology.

Side-Polish Plastic Optical Fiber Based SPR Sensor for Refractive Index and Liquid-Level Sensing.

In this work, a simple side-polish plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed and demonstrated for simultaneous measurement of refractive index (RI) and liquid level. The effects of side-polish depths on the sensing performance were studied. The experimental results show that the SPR peak wavelength will be changed as the RI changes, and the SPR peak intensity will be changed with the liquid level variation.

Symmetry Breaking and Anomalous Conductivity in a Double-Moiré Superlattice.

In a two-dimensional moiré superlattice, the atomic reconstruction of constituent layers could introduce significant modifications to the lattice symmetry and electronic structure at small twist angles. Here, we employ conductive atomic force microscopy to investigate a twisted trilayer graphene double-moiré superlattice. Two sets of moiré superlattices are observed.

Ion Hydration under Nanoscale Confinement: Dimensionality and Scale Effects.

How ions are hydrated in nanoconfined spaces is crucial for understanding many natural phenomena and practical applications, such as biological functionalities and energy conversion devices. In real systems, nanoconfinement shows structural diversity, but the influence of dimensionality and scale on ion hydration remains considerably unrevealed. Here, we study ion hydration under various confinements by systematic molecular dynamics simulations.

Borophane Polymorphs.

Hydrogenated borophenes─borophanes─have recently been synthesized as a new platform for studying low-dimensional borides, but most of their lattice structures remain unknown. Here, we determine the structures of borophane polymorphs on Ag(111) by performing extensive structural search using the cluster expansion method augmented with first-principles calculations. Our results reveal rich borophane polymorphs whose stability depends on hydrogen pressure.

Diagnostic Evaluation of 18F-FDG PET/CT Imaging in Recurrent or Residual Urinary Bladder Cancer: A Meta-Analysis.

Purpose: To assess the diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography combined with the computed tomography (18F-FDG PET/CT) in the detection of recurrent or residual urinary bladder cancer with meta-analysis.

Methods: We searched PubMed/MEDLINE, Embase, Web of Science, CBM, CNKI, VIP, and Wanfang databases through October 2019. Two reviewers independently screened the full articles.

[Analysis of genomic DNA methylation level in foxtail millet by Methylation Sensitive Amplified Polymorphism].

DNA methylation is an important type of epigenetic modification in eukaryotes. In order to research genome-wide methylation levels and patterns in foxtail millet (Setaria italica), the Methylation Sensitive Amplified Polymorphism (MSAP) analysis (employing double digestion with EcoR I and Hpa II/Msp I) was established and applied in two foxtail millet cultivars (Chaogu 58 and Yugu 1). The results showed that 32 pairs of MSAP primers were selected from 100 MSAP primers, and 1 615 and 1 482 clearly distinguishable and reproducible bands were amplified from Chaogu 58 and Yugu 1 respectively, including 3 types of methylation patterns.

Graphynes for Water Desalination and Gas Separation.

Selective transport of mass through membranes, so-called separation, is fundamental to many industrial applications, e.g., water desalination and gas separation.

Heterogeneous graphene oxide membrane for rectified ion transport.

Ion transport in nanoconfinement has drawn significant attention due to its crucial role in the functioning of biological nanochannels and in the stimulation of applications including iontronics, biosensing and energy conversion. Graphene oxide (GO) membranes that contain abundant two-dimensional nanochannels formed in-between stacked GO nanosheets are particularly attractive because they offer high tunability in terms of channel dimensions and surface properties. However, because of the inherent homogeneity of the GO membrane, ion transport through such nanochannels typically exhibit ohmic behaviour, inhibiting its potential widespread applications.