The spirobichroman-based polyimides with different side groups: from structure-property relationships to chain packing and gas transport performance.

Spirobichroman-based polymers with high gas permeability and selectivity are promising for their applications as membranes in gas separation. In this study, three spirobichroman-based polyimides (PIs; 6FDA-FH, 6FDA-DH, and 6FDA-MH) were synthesised by the polyreaction between diamines containing different substituents (benzene ring, pyridine ring, and methyl group) and 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The physical properties, gas transport behaviour, -spacing, dihedral angle of molecules, and fractional free volume of the PIs were investigated through experiments and molecular simulations.

Endowing magnesium with the corrosion-resistance property through cross-linking polymerized inorganic sol-gel coating.

The design of a highly adhesive, defect-free and low-temperature sol-gel coating for the protection of magnesium alloys is desirable yet challenging. In this study, a novel SiO-based sol-gel coating is developed by a ring-opening addition reaction. Notably, the integration of individual sol clusters endows the sol-gel coating with a smooth and compact surface morphology, and eliminates the potential corrosion site of the low-temperature-prepared sol-gel coating.

Rational Design of Multi-Color-Emissive Carbon Dots in a Single Reaction System by Hydrothermal.

As an emerging building unit, carbon dots (CDs) have been igniting the revolutionaries in the fields of optoelectronics, biomedicine, and bioimaging. However, the difficulty of synthesizing CDs in aqueous solution with full-spectrum emission severely hinders further investigation of their emission mechanism and their extensive applications in white light emitting diodes (LEDs). Here, the full-color-emission CDs with a unique structure consisting of -hybridized carbon cores with small domains of partially -hybridized carbon atoms are reported.

Mixed lead source precursors for producing light absorption layers of perovskite solar cells.

Beside the conventional perovskite precursors with lead halides as lead sources, non-halide lead sources provide additional tools for tuning the properties of perovskite layers, and lead acetate is a promising candidate for non-halide lead sources. In this work, we develop the perovskite precursor with a mixed non-halide lead source by partially replacing lead acetate with lead thiocyanate. Scanning electron microscopy and X-ray diffraction measurements indicate that lead thiocyanate additive can remarkably increase the size of perovskite grains and the crystallization of perovskite layers.

2D Materials and Heterostructures at Extreme Pressure.

2D materials possess wide-tuning properties ranging from semiconducting and metallization to superconducting, etc., which are determined by their structure, empowering them to be appealing in optoelectronic and photovoltaic applications. Pressure is an effective and clean tool that allows modifications of the electronic structure, crystal structure, morphologies, and compositions of 2D materials through van der Waals (vdW) interaction engineering.

O NMR spectroscopy-assisted bioactivity studies of the intermediates formed NaS and RSNO cross-linking reactions.

The cross-linking reaction between sulfide and -nitrosothiol moieties has been intensively investigated and thionitrite/thionitrous acid (SNO/HSNO) as well as nitrosopersulfide (SSNO) were reported to be the intermediates that could serve as reservoirs for nitric oxide (NO). However, debate still exists regarding the stability and biological activity of SNO/HSNO and SSNO. In order to investigate the chemical properties and biological activity of SNO and SSNO, we set out to re-characterize the reaction intermediates using UV-Vis and N NMR spectroscopy techniques, as well as a new O NMR approach.

Near-infrared-IIb probe affords ultrahigh contrast inflammation imaging.

Deep tissue imaging in the near-infrared II (NIR-II) window with significantly reduced tissue autofluorescence and scattering provides an important modality to visualize various biological events. Current commercially used contrast agents in the near-infrared spectrum suffer from severe photobleaching, high tissue scattering, and background signals, hampering high-quality bioimaging, particularly in small animals. Here, we applied a NIR-IIb quantum dot (QD) probe with greatly suppressed photon scattering and zero autofluorescence to map inflammatory processes.

Cd-Rich Alloyed CsPb Cd Br Perovskite Nanorods with Tunable Blue Emission and Fermi Levels Fabricated through Crystal Phase Engineering.

One-dimensional semiconductor nanostructures have already been used for a variety of optoelectronic applications. Metal halide perovskites have emerged in recent years as promising high-performance optoelectronic materials, but reports on 1D nanorods (NRs) of all-inorganic halide perovskites are still scarce. This work demonstrates a synthetic strategy toward cesium-based inorganic perovskite NRs by exploiting composition-controlled crystal phase engineering.

New Polymorphs of 2D Indium Selenide with Enhanced Electronic Properties.

The 2D semiconductor indium selenide (InSe) has attracted significant interest due its unique electronic band structure, high electron mobility, and wide tunability of its band gap energy achieved by varying the layer thickness. All these features make 2D InSe a potential candidate for advanced electronic and optoelectronic applications. Here, the discovery of new polymorphs of InSe with enhanced electronic properties is reported.

Synthesis of narrow-band curled carbon nitride nanosheets with high specific surface area for hydrogen evolution from water splitting by low-temperature aqueous copolymerization to form copolymers.

Carbon nitride has become a focus of photocatalytic materials research in recent years, but the low specific surface area, the bad separation efficiency of photocarriers, poor quantum efficiency, terrible photocatalytic activity hinder the development of carbon nitride in the field of photocatalysis. The preparation of carbon nitride nanosheets is one of the effective methods to improve the photocatalytic efficiency of carbon nitride, but the traditional top-down stripping process is time-consuming, complicated and expensive. Here we report a simple, cheap, non-toxic and environmentally friendly bottom-up method to prepare a curled g-CN nanosheet (NS-CN), which is performed at low temperature and normal pressure.

Thermoelectric Enhancements in PbTe Alloys Due to Dislocation-Induced Strains and Converged Bands.

In-grain dislocation-induced lattice strain fluctuations are recently revealed as an effective avenue for minimizing the lattice thermal conductivity. This effect could be integratable with electronic enhancements such as by band convergence, for a great advancement in thermoelectric performance. This motivates the current work to focus on the thermoelectric enhancements of p-type PbTe alloys, where monotelluride-alloying and Na-doping are used for a simultaneous manipulation on both dislocation and band structures.

Highly efficient, reversible iodine capture and exceptional uptake of amines in viologen-based porous organic polymers.

A viologen-based porous organic polymer, POP-V-VI, was designed and synthesized by a facile nucleophilic substitution between cyanuric chloride and 1,2-bis(4-pyridinium) ethylene. Together with the reported POP-V-BPY with a similar structure, these viologen-based porous organic polymers bear high charge density, phenyl ring and nitrogenous affinity sites, which endow them with excellent iodine vapor uptake capacity (4860 mg g for POP-V-VI and 4200 mg g for POP-V-BPY) and remarkably high adsorption capacity for pyridine (4470 mg g for POP-V-VI and 8880 mg g for POP-V-BPY) and other aliphatic amines. POP-V-VI and POP-V-BPY could be efficiently recycled and reused three times without significant loss of iodine vapor uptake.

Sol-gel-assisted micro-arc oxidation synthesis and characterization of a hierarchically rough structured Ta-Sr coating for biomaterials.

Tantalum (Ta) is an element with high chemical stability and ductility that is used in orthopedic biomaterials. When utilized, it can produce a bioactive surface and enhance cell-material interactions, but currently, there exist scarce effective methods to introduce the Ta element onto the surface of implants. This work reported a sol-gel-assisted approach combined with micro-arc oxidation (MAO) to introduce Ta onto the surface of the titanium (TC4) substrate.

Novel All-Nitrogen Molecular Crystals of Aromatic N.

Nitrogen has unique bonding ability to form single, double, and triple bonds, similar to that of carbon. However, a molecular crystal formed by an aromatic polynitrogen similar to a carbon system has not been found yet. Herein, a new form of stable all-nitrogen molecular crystals consisting of only bispentazole N molecules with exceedingly high energy density is predicted.

Enhancing the light emission of GaAs nanowires by pressure-modulated charge transfer.

Strong non-radiative surface recombination in GaAs nanowires heavily blocks their applications as nanoscale optoelectronic devices. Pressure can effectively affect the surface recombination behaviors through tuning interactions between the surface of nanomaterials and the medium environment. Here, we report the pressure-induced light emission enhancement in GaAs nanowires high pressure photoluminescence measurements with nitrogen as the pressure transmitting medium.

Bonding properties of a superatom system with high- elements: insights from energy decomposition analysis.

Superatoms with high- elements have novel physicochemical properties, and a comprehensive and thorough view of their bonding properties plays a crucial role in the design of superatoms. Now, energy decomposition analysis shows increasingly prominent performance for understanding inter- and intra-molecular interactions, so the bonding properties of typical superatoms with high- elements, Th@Au, have been investigated here. It is found that under different electron occupation types of the fragments, the electrostatic interaction energy, polarization, and exchange repulsion energy change significantly in their intramolecular interaction energy components, resulting in quantitative or even qualitative differences in their main interaction energy.

Photo-Disassembly of Membrane Microdomains Revives Conventional Antibiotics against MRSA.

Confronted with the rapid evolution and dissemination of antibiotic resistance, there is an urgent need to develop alternative treatment strategies for drug-resistant pathogens. Here, an unconventional approach is presented to restore the susceptibility of methicillin-resistant (MRSA) to a broad spectrum of conventional antibiotics via photo-disassembly of functional membrane microdomains. The photo-disassembly of microdomains is based on effective photolysis of staphyloxanthin, the golden carotenoid pigment that gives its name.

Pressure-Induced Structural Evolution and Bandgap Optimization of Lead-Free Halide Double Perovskite (NH)SeBr.

Lead-free halide double perovskites (HDPs) are promising candidates for high-performance solar cells because of their environmentally-friendly property and chemical stability in air. The power conversion efficiency of HDPs-based solar cells needs to be further improved before their commercialization in the market. It requires a thoughtful understanding of the correlation between their specific structure and property.

Gain characteristics of the hybrid slot waveguide amplifiers integrated with NaYF:Er NPs-PMMA covalently linked nanocomposites.

Waveguide amplifiers based on slot waveguide have enormous capacity due to their ability to confine light strongly to a narrow slot waveguide. NaYF:Er nanoparticles-polymeric methyl methacrylate covalently linked nanocomposites were synthesized and filled into the slot. The stability and the Er concentration doped in this novel material were improved.

A comparative study of high-pressure behaviors of the two polymorphs of HoGeO.

Two polymorphs of polycrystalline HoGeO, one with tetragonal structure and the other with cubic structure, were synthesized by using different methods. The structural stabilities of these two polymorphs under high pressure were investigated by angle-dispersive X-ray diffraction (ADXRD). Pressure-induced amorphization was found in the tetragonal HoGeO, which is suggested to be associated with the breaking-up of long chains of the edge-shared polyhedron group HoO.

Fast-response humidity sensor based on laser printing for respiration monitoring.

Respiration monitoring equipment has wide applications in daily health monitoring and modern medical diagnosis. Despite significant progress being made in humidity sensors for respiration monitoring, the fabrication of the humidity sensors with low-cost, simple manufacturing process and easy integration remains a challenge. This work reports a facile and inexpensive laser printing fabrication of PEDOT:PSS micron line as a humidity sensor for respiration monitoring.

High-pressure formation of antimony nitrides: a first-principles study.

The structural phase transition, electronic properties, and bonding properties of antimony nitrides have been studied by using the first principles projector augmented wave method. The relationship between the formation enthalpy and the composition of the Sb-N system has been explored. The novel SbN with the space group is stable in a narrow pressure range from 100 GPa to 120 GPa.

Biaxial strain modulated the electronic structure of hydrogenated 2D tetragonal silicene.

Silicene-based materials have attracted great attention due to their easier incorporation into silicon-based devices and components. In addition to the reported hydrogenated 2D tetragonal silicene (γ-SiH), we propose two stable atomic configurations of hydrogenated 2D tetragonal silicene (α-SiH and β-SiH) based on first-principles calculation. The calculated results indicate hydrogenation can effectively open the band gap of 2D tetragonal silicene, α-SiH is a semiconductor with a direct band gap of 2.

The photogenerated charge characteristics in Ni@NiO/CdS hybrids for increased photocatalytic H generation.

Solar-driven H generation from water splitting with semiconductor materials is considered an effective solution to solve the problems of energy shortage and environmental pollution at a low cost. In this study, a highly efficient photocatalyst Ni@NiO/CdS for H evolution was synthesised using a simple solvothermal method and calcination. The HRTEM results and elemental mapping tests confirmed that Ni@NiO was successfully loaded on the surface of CdS.