Keenejosefsen8723

Thermal manipulation in nanowires (NWs) is of great significance for NW-based applications in the area of heat management and energy harvesting. Here, we experimentally demonstrate thermal conductivity manipulation and thermal rectification in π-stacked metallophthalocyanine (MPcs) NWs. By electron beam (E-beam) irradiation with a controllable dose, the thermal conductance of MPcs NWs can be continuously tuned to the desired values. Three thermal rectifiers were further tested on crystal-amorphous heterostructures and the thermal rectification was found to be 3.3% with a temperature bias of 10 K when T = 40 K, which is consistent with COMSOL simulations.The existence of a morphotropic phase boundary (MPB) inside HfO2-ZrO2 solid solution thin films has been predicted; if it exists, it provides a new path toward an ideal silicon-compatible dielectric. Herein, we investigate the structural evolution along with the dielectric and ferroelectric behaviors of differently designed HfO2-ZrO2 thin films to engineer the density of the MPB inside the film structure and consequently, enhance the dielectric properties. Polarization vs. electric field (P-E) measurements of Hf0.25Zr0.75O2 thin films reveal ferroelectric (FE)-antiferroelectric (AFE) characteristics. For this composition, the dielectric constant εr is higher than those of FE Hf0.5Zr0.5O2 and AFE ZrO2 thin films; the difference is attributed to the formation of the MPB. To increase the density of the MPB and subsequently the dielectric properties, 10 nm Hf0.5Zr0.5O2 (FE)/ZrO2 (AFE) nanolaminates were prepared with different lamina thicknesses tL. The coexistence of FE and AFE properties was confirmed by structural characterization studies and P-E measurements. 3BDO solubility dmso The thinnest layered nanolaminate (tL = 6 Å) showed the strongest dielectric constant εr∼ 60 under a small signal ac electric field of ∼50 kV cm-1; this is the highest εr so far observed in HfO2-ZrO2 thin films. This behavior was attributed to the formation of an MPB near FE/AFE interfaces. The new design provides a promising approach to achieve an ideal high-κ CMOS-compatible device for the current electronic industry.Twistronics has emerged as one of the most attractive playgrounds for manipulating the interfacial structures and electronic properties of two-dimensional materials. However, the layer-dependent lattice reconstruction and resulted strain distribution in marginally twisted transition metal dichalcogenides still remain elusive. Here we report a systematic study by both electron diffraction quantification and atomic-resolution imaging on the interface reconstruction of twisted WSe2, which shows a strong dependence on the constituent layer numbers and twist angles. link2 The competition between the interlayer interaction, which varies with local atomic configurations, and the intralayer elastic deformation, related to the layer thickness, leads to rich superlattice motifs and strain modulation patterns, i.e. triangular for odd and kagome-like textures for even layer numbers, against the rigid stacking moiré model. The strain effects of small twist angles are further demonstrated by electrical transport measurements, manifesting intriguing conducting states at low temperatures beyond the flat band features of large twist angles. Our work not only provides a comprehensive understanding of layer-dependent twist structures, but also may shed light on the future design of twistronic devices.Controlling the identity of the tip-terminating atom or molecule in low-temperature atomic force microscopy has led to ground breaking progress in surface chemistry and nanotechnology. Lacking a comparative tip-performance assessment, a profound standardization in such experiments is highly desirable. Here we directly compare the imaging and force-spectroscopy capabilities of four atomically defined tips, namely Cu-, Xe-, CO-, and O-terminated Cu-tips (CuOx-tips). Using a nanostructured copper-oxide surface as benchmark system, we found that Cu-tips react with surface oxygen, while chemically inert Xe- and CO-tips allow entering the repulsive force regime enabling increased resolution. However, their high flexibility leads to imaging artifacts and their strong passivation suppresses the chemical contrast. The higher rigidity and selectively increased chemical reactivity of CuOx-tips prevent tip-bending artifacts and generate a distinct chemical contrast. This result is particularly promising in view of future studies on other metal-oxide surfaces.Biofilm-related infections, such as dental plaque, chronic sinusitis, native valve endocarditis, and chronic airway infections in cystic fibrosis have brought serious suffering to patients and financial burden to society. Materials that can eliminate mature biofilms without developing drug resistance are promising tools to treat biofilm-related infections, and thus they are in urgent demand. Herein, we designed and readily prepared organic nanoparticles (NPs) with highly efficient photothermal conversion by harvesting energy via excited-state intramolecular motions and enlarging molar absorptivity. The photothermal NPs can sufficiently eliminate mature bacterial biofilms upon low-power near-infrared laser irradiation. NPs hold great promise for the rapid eradication of bacterial biofilms by photothermal therapy.The alkaline electrocatalytic hydrogen evolution reaction (HER) is a potential way to realize industrial hydrogen production. However, the sluggish process of H2O dissociation, as well as the accumulation of OH- around the active sites, seriously limit the alkaline HER performance. In this work, we developed a unique CoS2 needle array grown on a carbon cloth (NAs@C) electrode as an alkaline HER catalyst. Finite-element simulations revealed that CoS2 needle arrays (NAs) induce stronger local electric field (LEF) than CoS2 disordered needles (DNs). This LEF can greatly repel the local OH- around the active sites, and then promote the forward H2O dissociation process. The local pH changes of the electrode surface confirmed the lower OH- concentration and stronger local pseudo-acidic environment of NAs@C compared to those of DNs@C. As a result, the NAs@C catalyst exhibited a low HER overpotential of 121 mV at a current density of 10 mA cm-2 in 1 M KOH, with the Tafel slope of 59.87 mV dec-1. This work provides a new insight into nanoneedle arrays for the alkaline HER by electric field-promoted H2O dissociation.The conversion of solar energy into usable chemical fuels, such as hydrogen gas, via photo(electro)chemical water splitting is a promising approach for creating a carbon neutral energy ecosystem. The deployment of this technology industrially and at scale requires photoelectrodes that are highly active, cost-effective, and stable. To create these new photoelectrodes, transition metal-based electrocatalysts have been proposed as potential cocatalysts for improving the performance of water splitting catalysts. Layered double hydroxides (LDHs) are a class of clays with brucite like layers and intercalated anions. Transition metal-based LDHs are increasingly popular in the field of photo(electro)chemical water splitting due to their unique physicochemical properties. This article aims to review recent advances in transition metal-based LDHs for photo(electro)chemical water splitting. This article provides a brief overview of the research in a format approachable for the general scientific audience. Specifically, this review examines the following areas (i) routes for synthesis of transition metal-based LDHs, (ii) recent developments in transition metal-based LDHs for photo(electro)chemical water splitting, and (iii) an overview of the structure-property relationships therein.Half a century ago, F. Albert Cotton emphasized the relevance of metal-metal bonding in the constitution of cluster materials. Based on his description, nanoscale polyoxometalates (POMs) normally would not be regarded as cluster materials. One reason is that metal-metal bonding is typically associated with inorganic systems featuring metal centres in low oxidation states, a feature that is not common for POMs. However, over the past decades, there have been increasing reports on POMs integrating different types of metal-metal bonding. This article conceptualises and reviews the area of metal-metal bonded POMs, and their preparation and physicochemical properties. Attention is given to the changes in the electronic structure of POMs, the emergence of covalent dynamics and its impact on the development of applications in catalysis, nanoswitches, donor-acceptor systems, electron storage materials and nanoelectronics (i.e., "POMtronics").The engineering of core@multi-shell nanoparticles containing heterogeneous crystalline phases in different layers constitutes an important strategy for obtaining optical probes. link3 The possibility of obtaining an opto-magnetic core@multi-shell nanoparticle capable of emitting in the visible and near-infrared ranges by upconversion and downshifting processes is highly desirable, especially when its optical responses are dependent on temperature and magnetic field variations. This work proposes the synthesis of hierarchically structured core@multi-shell nanoparticles of heterogeneous crystalline phases a cubic core containing DyIII ions responsible for magnetic properties and optically active hexagonal shells, where ErIII, YbIII, and NdIII ions were distributed. This system shows at least three excitation energies located at different biological windows, and its emission intensities are sensitive to temperature and external magnetic field variations. The selected crystalline phases of the core@multi-shell nanoparticles obtained in this work is fundamental to the development of multifunctional materials with potential applications as temperature and magnetic field optical probes.In this study, we aimed to achieve an efficient repair of damaged skeletal muscles using polyvinyl alcohol (PVA) soluble microneedle patches (MNP) loaded with carbonized wormwood and prostaglandin E2 (inflammatory factors). The introduction of carbonized wormwood imparted the MNP with near-infrared light heating characteristics that improved the efficiency of prostaglandin E2 delivery while also promoting circulation in the damaged muscle area. Our experimental results showed that, compared with the classical moxibustion treatment, the system could more quickly restore muscle strength and the cross-sectional area of muscle bundle fibers in a mouse model of muscular injury. In addition, it could also successfully induce the proliferation and differentiation of muscle stem cells to effectively repair injured muscle tissues. Above all, this light-controlled photothermal MN (microneedle) drug-delivery system avoided the common problems of traditional moxibustion such as large levels of smoke, slow efficacy and risk of scalding. Collectively, we put forward a safe, accurate and efficient approach for skeletal muscle damage treatment using carbonized wormwood.A straightforward one-pot method for the synthesis of unreported pyrido-[2,1-a]isoindolones in excellent yield is described. Two novel isoindolones were synthesized and fully characterized. The alkyl substituents on the pyridine play an important role in the outcome of the reaction. The mechanism, investigated through DFT calculations, features an unprecendented intramolecular cyclization reaction involving a carboxylic acid activated by tosyl chloride and an electron-poor pyridinic nitrogen. This protocol completes the known strategies to obtain functionalized isoindolones.