ChemInform Abstract: First‐Principles Molecular Dynamics Investigation on Na3AlF6 Molten Salt.

The partial radial distribution function, coordination numbers, bond angles, F atoms type, self‐diffusion coefficient, viscosity, and ionic conduction of molten Na₃AlF₆ are investigated by first‐principles molecular dynamics simulation.     

Two‐Dimensional Layered Heterostructures Synthesized from Core–Shell Nanowires

Controlled stacking of different two‐dimensional (2D) atomic layers will greatly expand the family of 2D materials and broaden their applications. A novel approach for synthesizing MoS₂/WS₂ heterostructures by chemical vapor deposition has been developed. The successful synthesis of pristine MoS₂/WS₂ heterostructures is attributed to using core–shell WO_3?x/MoO_3?x nanowires as a precursor, which naturally ensures the sequential growth of MoS₂ and WS₂. The obtained heterostructures exhibited high crystallinity, strong interlayer interaction, and high mobility, suggesting their promising applications in nanoelectronics. The stacking orientations of the two layers were also explored from both experimental and theoretical aspects. It is elucidated that the rational design of precursors can accurately control the growth of high‐quality 2D heterostructures. Moreover, this simple approach opens up a new way for creating various novel 2D heterostructures by using a large variety of heteronanomaterials as precursors.     

Multistimuli‐Responsive,Moldable Supramolecular Hydrogels Cross‐Linked by Ultrafast Complexation of Metal Ions and Biopolymers

A new type of multistimuli‐responsive hydrogels cross‐linked by metal ions and biopolymers is reported. By mixing the biopolymer chitosan (CS) with a variety of metal ions at the appropriate pH values, we obtained a series of transparent and stable hydrogels within a few seconds through supramolecular complexation. In particular, the CS–Ag hydrogel was chosen as the model and the gelation mechanism was revealed by various measurements. It was found that the facile association of Ag⁺ ions with amino and hydroxy groups in CS chains promoted rapid gel‐network formation. Interestingly, the CS–Ag hydrogel exhibits sharp phase transitions in response to multiple external stimuli, including pH value, chemical redox reactions, cations, anions, and neutral species. Furthermore, this soft matter showed a remarkable moldability to form shape‐persistent, free‐standing objects by a fast in situ gelation procedure.     

Luminescence Properties of Ca2Ga2SiO7:RE Phosphors for UV White‐Light‐Emitting Diodes

A series of Eu²⁺‐, Ce³⁺‐, and Tb³⁺‐doped Ca₂Ga₂SiO₇ phosphors is synthesized by using a high‐temperature solid‐state reaction. The powder X‐ray diffraction and structure refinement data indicate that our prepared phosphors are single phased and the phosphor crystalizes in a tetrahedral system with the ${P\bar 42m}$ (113) space group. The Eu²⁺‐ and Ce³⁺‐doped phosphors both have broad excitation bands, which match well with the UV light‐emitting diodes chips. Under irradiation of λ=350 nm, Ca₂Ga₂SiO₇:Eu²⁺ and Ca₂Ga₂SiO₇:Ce³⁺, Li⁺ have green and blue emissions, respectively. Luminescence of Ca₂Ga₂SiO₇:Tb³⁺, Li⁺ phosphor varies with the different Tb³⁺ contents. The thermal stability and energy‐migration mechanism of Ca₂Ga₂SiO₇:Eu²⁺ are also studied. The investigation results indicate that the prepared Ca₂Ga₂SiO₇:Eu²⁺ and Ca₂Ga₂SiO₇:Ce³⁺, Li⁺ samples show potential as green and blue phosphors, respectively, for UV‐excited white‐light‐emitting diodes.     

An ultra high performance liquid chromatography with tandem mass spectrometry method for plasma and cerebrospinal fluid pharmacokinetics of rhein in patients with traumatic brain injury after administration of rhubarb decoction

Damage of blood–brain barrier is a common result of traumatic brain injury. This damage can open the blood–brain barrier and allow drug passage. An ultraperformance liquid chromatography with tandem mass spectrometry method was established to determine the concentration of rhein in the biofluids (plasma and cerebrospinal fluid) of patients with a compromised blood–brain barrier following traumatic brain injury after rhubarb administration. Furthermore, the pharmacokinetic profiles were analyzed. A triple‐quadruple tandem mass spectrometer with electrospray ionization was used for rhein detection. The mass transition followed was m/z 283.06→239.0. The calibration curve was linear in the concentration range of 10–8000 ng/mL for the biofluids. The intra‐ and interday precisions were less than 10%. The relative standard deviation of recovery was less than 15% in biological matrices. The pharmacokinetic data showed that rhein was rapidly transported into biofluids, and exhibited a peak concentration 1 h after rhubarb administration. The elimination rate of rhein was slow. The AUC_{cerebrospinal fluid}/AUC_plasma (AUC is area under curve) of rhein was approximately 17%, indicating that portions of rhein could pass the impaired blood–brain barrier. The method was successfully applied to quantify rhein in the biofluids of all patients. The data presented can help to guide clinical applications of rhubarb for treating traumatic brain injury.     

A new approach to detect a set of SNP-SNP markers: Combining ARMS-PCR with SNaPshot technology

Microhaplotypes are a new promising type of forensic genetic marker. Without the interference of stutter and high mutation rates as for STRs, and with short amplification lengths and a higher degree of polymorphism than single SNP, microhaplotypes composed of two SNPs, SNP–SNP, have a strong application potential. Currently, the most common method to detect microhaplotypes is massive parallel sequencing. However, the cost and extensive use of instruments limit its wide application in forensic laboratories. In this study, we screened 23 new SNP–SNP loci and established a new detection method by combining a multiplex amplification refractory mutation system-based PCR (ARMS-PCR) and SNaPshot technology based on CE. First, we introduced an additional deliberate mismatch at the antepenultimate base from the 3′ end of primers when designing ARMS-PCR for SNP 1 (the first SNP of the SNP–SNP). Then, single base extension primers for SNaPshot assay were designed next to the position of SNP 2 (the second SNP). Finally, 15 loci were successfully built into four panels and these loci showed a relatively high level of polymorphism in the Southwest Chinese Han population. All the loci had an average probability of informative genotypes (I value) of 0.319 and a combined discrimination power of 0.999999999. Therefore, this new detection system will provide a valuable supplement to current methods.     

High-Efficiency Perovskite Solar Cells Enabled by Anatase TiO2 Nanopyramid Arrays with an Oriented Electric Field

One-dimensional (1D) nanostructured oxides are proposed as excellent electron transport materials (ETMs) for perovskite solar cells (PSCs); however, experimental evidence is lacking. A facile hydrothermal approach was employed to grow highly oriented anatase TiO₂ nanopyramid arrays and demonstrate their application in PSCs. The oriented TiO₂ nanopyramid arrays afford sufficient contact area for electron extraction and increase light transmission. Moreover, the nanopyramid array/perovskite system exhibits an oriented electric field that can increase charge separation and accelerate charge transport, thereby suppressing charge recombination. The anatase TiO₂ nanopyramid array-based PSCs deliver a champion power conversion efficiency of approximately 22.5 %, which is the highest power conversion efficiency reported to date for PSCs consisting of 1D ETMs. This work demonstrates that the rational design of 1D ETMs can achieve PSCs that perform as well as typical mesoscopic and planar PSCs.     

A Nano-shield Design for Separators to Resist Dendrite Formation in Lithium-Metal Batteries

Lithium dendrite growth during repeated charge and discharge cycles of lithium-metal anodes often leads to short-circuiting by puncturing the porous separator. Here, a morphological design, the nano-shield, for separators to resist dendrites is presented. Through both mechanical analysis and experiment, it is revealed that the separator protected by the nano-shield can effectively inhibit the penetration of lithium dendrites owing to the reduced stress intensity generated and therefore mitigate the short circuit of Li metal batteries. More than 110 h of lithium plating life is achieved in cell tests, which is among the longest cycle life of lithium metal anode and five times longer than that of blank separators. This new aspect of morphological and mechanical design not only provides an alternative pathway for extending lifetime of lithium metal anodes, but also sheds light on the role of separator engineering for various electrochemical energy storage devices.