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In recent years all-solid-state sodium-ion batteries (SS-SIBs) have drawn significant attention due to their potential to be safer and lower cost than lithium-ion batteries. However, the lack of sodium solid-state electrolytes with high ionic conductivity has become one of the major challenges. Here, with first-principles computation we took NaCuZrS 3 , consisting of earth-abundant and environmentally benign elements only, as an example to study Na-ion transport in the post-perovskite-like structure and used computation-guided design to improve its potential as a solid-state electrolyte. With ab initio molecular dynamics simulation and nudged elastic band calculation, we studied possible diffusion mechanisms in this material and found that Na ion interstitials have a favorable migration barrier of 0.22 eV, which is among the smallest in the literature reported values. Considering the large formation energy of Frenkel defects, we proposed doping strategy to introduce extra Na interstitials in the material. Our study suggests that the post-perovskite-like sulfides are worth of exploration for applications in SS-SIBs., (© 2022 Wiley-VCH GmbH.)

Low-dimensional organic-metal halides are regarded as an emerging class of X-ray scintillation materials, but most of the discovered compounds are confronted with challenges of toxicity and instability. To address these challenges, we herein report two lead-free zero-dimensional (0D) hybrid halides, (Bmpip) 2 Cu 2 Br 4 and PPh 4 CuBr 2 single crystals, grown by the low-cost solution-processing method. By single-crystal X-ray diffraction refinement, the crystal structures of (Bmpip) 2 Cu 2 Br 4 and PPh 4 CuBr 2 were determined to be orthorhombic and monoclinic crystal systems, respectively. (Bmpip) 2 Cu 2 Br 4 and PPh 4 CuBr 2 show broadband orange and yellow emissions peaking at 620 and 538 nm, respectively. Different from the emission nature of the recent reported Cu-based halide hybrids, both (Bmpip) 2 Cu 2 Br 4 and PPh 4 CuBr 2 emit from excitons bound to defects featuring spin-allowed transition, enabling them to possess fast scintillation decay time of tens of nanoseconds, respectively. In particular, the (Bmpip) 2 Cu 2 Br 4 single crystal has a high photoluminescence quantum yield of 48.2%, a high scintillation yield of 16,000 photons/MeV, and a low detection limit of 710 nGy air /s. Due to the combination of nontoxicity, long-term stability, and decent detection performance, (Bmpip) 2 Cu 2 Br 4 could be regarded as a promising X-ray scintillator.

We aimed to establish a 1-Deoxynojirimycin (DNJ) sustained-release delivery system to improve the hypoglycemic effect of DNJ. We used a transdermal diffusion meter in an in vitro orthogonal experiment to determine the optimal composition of the DNJ sustained-release transdermal system. Based on the in vitro analysis results, a sustained-release patch was prepared, and its pharmacokinetics and other properties were determined in vivo. The results showed that 30% hydroxypropyl methylcellulose (K 100M ), 14% carboxymethyl cellulose sodium and 26% oleic acid-azone compound as the matrix material, drug excipient, and penetration enhancer, respectively, produced an optimal DNJ sustained-release delivery system. In vitro release tests showed that the system slowly released DNJ within 12 hr, conforming to the Higuchi equation. In vivo experiments showed that the prepared patch had good hypoglycemic activity and continuously released DNJ within 10 hr. In vivo pharmacokinetic study results showed that compared to conventional patches, the prepared patch exhibited significantly different maximum concentration (C max ), time to achieve C max (T max ), and area under the curve from 0 to time t (AUC [0-t] ) as well as improved pharmacokinetics. In conclusion, the prepared DNJ patch has high stability, a sustained-release effect, and relatively good pharmacokinetics and is a safe dosage form that does not cause skin irritation., (© 2021 Wiley Periodicals LLC.)

The development of functional materials calls for ever-enriching the inorganic material database. Doping is an effective way of achieving this purpose. Herein, we propose the concept of dilute element compounds (DECs), which contain a small amount of a dopant element distributed in a host crystal structure in an ordered manner. Different from dilute alloys or solid solutions, the DECs could be more resistant to segregation and are ideal for dispersing functional elements for applications such as single-atom catalysts. It is also expected that the DECs will serve as a route to discovering new inorganic functional materials by controlling phase transitions and tuning intrinsic properties of the host materials with applications including, but not limited to, thermoelectrics and solid-state electrolytes for secondary batteries. As an initial work, we quantify the diluteness of DECs and find the limits of diluteness in existing DECs. We further provide a classification scheme for the DECs to guide future discoveries.

Hard carbons (HCs) as an anode material in sodium ion batteries present enhanced electrochemical performances in ether-based electrolytes, giving them potential for use in practical applications. However, the underlying mechanism behind the excellent performances is still in question. Here, ex situ nuclear magnetic resonance, gas chromatography-mass spectrometry, and high-resolution transmission electron microscopy were used to clarify the insightful chemistry of ether- and ester-based electrolytes in terms of the solid-electrolyte interphase (SEI) on hard carbons. The results confirm the marked electrolyte decomposition and the formation of a SEI film in EC/DEC but no SEI film in the case of diglyme. In situ electrochemical quartz crystal microbalance and molecular dynamics support that ether molecules have likely been co-intercalated into hard carbons. To our knowledge, these results are reported for the first time. It might be very useful for the rational design of advanced electrode materials based on HCs in the future., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Organic-inorganic hybrids may offer material properties not available from their inorganic components. However, they are typically less stable and disordered. Long-term stability study of the hybrid materials, over the anticipated lifespan of a real-world electronic device, is practically nonexistent. Disordering, prevalent in most nanostructure assemblies, is a prominent adversary to quantum coherence. A family of perfectly ordered II-VI-based hybrid nanostructures has been shown to possess many unusual properties and potential applications. Here, using a prototype structure β-ZnTe(en) 0.5 -a hybrid superlattice-and applying an array of optical, structural, surface, thermal, and electrical characterization techniques, in conjunction with density-functional theory calculations, we have performed a comprehensive and correlative study of the crystalline quality, structural degradation, electronic, optical, and transport properties on samples from over 15 years old to the recently synthesized. The findings show that not only do they exhibit an exceptionally high level of crystallinity in both macroscopic and microscopic scale, comparable to high-quality binary semiconductors; and greatly enhanced material properties, compared to those of the inorganic constituents; but also, some of them over 15 years old remain as good in structure and property as freshly made ones. This study reveals (1) what level of structural perfectness is achievable in a complex organic-inorganic hybrid structure or a man-made superlattice, suggesting a nontraditional strategy to make periodically stacked heterostructures with abrupt interfaces; and (2) how the stability of a hybrid material is affected differently by its intrinsic attributes, primarily formation energy, and extrinsic factors, such as surface and defects. By correlating the rarely found long-term stability with the calculated relatively large formation energy of β-ZnTe(en) 0.5 and contrasting with the case of hybrid perovskite, this work illustrates that formation energy can serve as an effective screening parameter for the long-term stability potential of hybrid materials. The results of the prototype II-VI hybrid structures will, on one hand, inspire directions for future exploration of the hybrid materials, and, on the other hand, provide metrics for assessing the structural perfectness and long-term stability of the hybrid materials.

Tuning metal-support interaction has been considered as an effective approach to modulate the electronic structure and catalytic activity of supported metal catalysts. At the atomic level, the understanding of the structure-activity relationship still remains obscure in heterogeneous catalysis, such as the conversion of water (alkaline) or hydronium ions (acid) to hydrogen (hydrogen evolution reaction, HER). Here, we reveal that the fine control over the oxidation states of single-atom Pt catalysts through electronic metal-support interaction significantly modulates the catalytic activities in either acidic or alkaline HER. Combined with detailed spectroscopic and electrochemical characterizations, the structure-activity relationship is established by correlating the acidic/alkaline HER activity with the average oxidation state of single-atom Pt and the Pt-H/Pt-OH interaction. This study sheds light on the atomic-level mechanistic understanding of acidic and alkaline HER, and further provides guidelines for the rational design of high-performance single-atom catalysts.

Cs 2 SnI 6 perovskite displays excellent air stability and a high absorption coefficient, promising for photovoltaic and optoelectronic applications. However, Cs 2 SnI 6 -based device performance is still low as a result of lacking optimized synthesis approaches to obtain high quality Cs 2 SnI 6 crystals. Here, a new simple method to synthesize single crystalline Cs 2 SnI 6 perovskite at a liquid-liquid interface is reported. By controlling solvent conditions and Cs 2 SnI 6 supersaturation at the liquid-liquid interface, Cs 2 SnI 6 crystals can be obtained from 3D to 2D growth with controlled geometries such as octahedron, pyramid, hexagon, and triangular nanosheets. The formation mechanisms and kinetics of complex shapes/geometries of high quality Cs 2 SnI 6 crystals are investigated. Freestanding single crystalline 2D nanosheets can be fabricated as thin as 25 nm, and the lateral size can be controlled up to sub-millimeter regime. Electronic property of the high quality Cs 2 SnI 6 2D nanosheets is also characterized, featuring a n-type conduction with a high carrier mobility of 35 cm 2 V -1 s -1 . The interfacial reaction-controlled synthesis of high-quality crystals and mechanistic understanding of the crystal growth allow to realize rational design of materials, and the manipulation of crystal growth can be beneficial to achieve desired properties for potential functional applications., (© 2020 Wiley-VCH GmbH.)

BaZrS 3 , a prototypical chalcogenide perovskite, has been shown to possess a direct band gap, an exceptionally strong near band edge light absorption, and good carrier transport. Coupled with its great stability, nontoxicity with earth-abundant elements, it is thus a promising candidate for thin film solar cells. However, its reported band gap in the range of 1.7-1.8 eV is larger than the optimal value required to reach the Shockley-Queisser limit of a single-junction solar cell. Here, we report the synthesis of Ba(Zr 1- x Ti x )S 3 perovskite compounds with a reduced band gap. It is found that Ti-alloying is extremely effective in band gap reduction of BaZrS 3 : a mere 4 atom % alloying decreases the band gap from 1.78 to 1.51 eV, resulting in a theoretical maximum power conversion efficiency of 32%. Higher Ti-alloying concentration is found to destabilize the distorted chalcogenide perovskite phase., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

β-FeSi 2 has long been investigated as a promising thermoelectric (TE) material working at high temperatures due to its combining features of environmental friendliness, good thermal stability, and strong oxidation resistance. However, the real application of β-FeSi 2 is still limited by its low TE figure of merit ( zT ). In this study, nearly doubled zT in p-type β-FeSi 2 has been achieved via synergistically optimizing electrical and thermal transports. Based on the first-principles calculations, Al with shallow acceptor transition level and high carrier donation efficiency is chosen to dope β-FeSi 2 . Significantly improved electrical transport, particularly in the low temperature range, has been obtained in the Al-doped β-FeSi 2 system. The power factor for FeSi 1.96 Al 0.04 at 300 K is even higher than that of p-type β-FeSi 2 -based compounds reported previously at high temperatures. By alloying β-FeSi 2 with Os at the Fe sites, we further lower the lattice thermal conductivity. Fe 0.80 Os 0.20 Si 1.96 Al 0.04 possesses the lowest lattice thermal conductivity among the β-FeSi 2 compounds prepared by the equilibrium method. Finally, a record-high zT value of 0.35 is obtained for p-type Fe 0.80 Os 0.20 Si 1.96 Al 0.04 . This study is expected to accelerate the application of β-FeSi 2 .

An exceptionally strong solvation effect of dimethyl sulfoxide (DMSO) on I 2 is identified by the largest shift observed so far of the I 2 Raman peak with respect to I 2 vapor and by elongated I-I bond lengths in first-principles molecular-dynamics simulations. This effect together with strong binding by an RuO 2 surface to I 2 is found to invert the direction of the reaction I - +I 2 ⇌I 3 - to the left-hand side. Inspired by this finding, we prepared a Li-O 2 battery with the Li/DMSO+LiI/RuO 2 structure. The synergic action of DMSO and RuO 2 on I 2 is found to suppress the shuttle effect of the redox mediator (RM) by anchoring I 2 molecules, the oxidation product of the RM. Significantly enhanced stability is demonstrated over 100 cycles at charging voltage below 3.65 V., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

As soluble catalysts, redox mediators can reduce the high charging overpotential of lithium-oxygen batteries by providing sufficient liquid-solid interface for lithium peroxide decomposition. However, the redox mediators usually introduce undesirable reactions. In particular, the so-called "shuttle effect" leads to the loss of both the redox mediators and electrical energy efficiency. In this study, an organic compound, triethylsulfonium iodide, is found to act bifunctionally as both a redox mediator and a solid electrolyte interphase-forming agent for lithium-oxygen batteries. During charging, the organic iodide exhibits comparable lithium peroxide-oxidizing capability with inorganic iodides. Meanwhile, it in situ generates an interfacial layer on lithium anode via reductive ethyl detaching and the subsequent oxidation. This layer prevents the lithium anode from reacting with the redox mediators and allows efficient lithium-ion transfer leading to dendrite-free lithium anode. Significantly improved cycling performance has been achieved by the bifunctional organic iodide redox mediator.

Understanding and controlling of excited carrier dynamics is of fundamental and practical importance, particularly in photochemistry and solar energy applications. However, theory of energy relaxation of excited carriers is still in its early stage. Here, using ab initio molecular dynamics (MD) coupled with time-dependent density functional theory, we show a coverage-dependent energy transfer of photoexcited carriers in hydrogenated graphene, giving rise to distinctively different ion dynamics. Graphene with sparsely populated H is difficult to dissociate due to inefficient transfer of the excitation energy into kinetic energy of the H. In contrast, H can easily desorb from fully hydrogenated graphane. The key is to bring down the H antibonding state to the conduction band minimum as the band gap increases. These results can be contrasted to those of standard ground-state MD that predict H in the sparse case should be much less stable than that in fully hydrogenated graphane. Our findings thus signify the importance of carrying out explicit electronic dynamics in excited-state simulations.

There is growing interest in the ability of phytochemicals to prevent chronic diseases, such as cancer and heart disease. However, some of these agents have poor bioavailability and many of the in-depth studies into their mechanisms of action have been carried out in vitro using doses which are unachievable in humans. In order to optimize the design of chemopreventive treatment, it is important to determine which of the many reported mechanisms of action are clinically relevant. In this review we consider the physiologically achievable doses for a few of the best studied agents (indole-3-carbinol, diindolylmethane, curcumin, epigallocatechin-3-gallate and resveratrol) and summarize the data derived from studies using these low concentrations in cell culture. We then cite examples of in vitro effects which have been observed in vivo. Finally, the ability of agent combinations to act synergistically or antagonistically is considered. We conclude that each of the compounds shows an encouraging range of activities in vitro at concentrations which are likely to be physiologically relevant. There are also many examples of in vivo studies which validate in vitro observations. An important consideration is that combinations of agents can result in significant activity at concentrations where any single agent is inactive. Thus, for each of the compounds reviewed here, in vitro studies have provided useful insights into their mechanisms of action in humans. However, data are lacking on the full range of activities at low doses in vitro and the benefits or otherwise of combinations in vivo.