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Solid-state electrical conducting materials can be roughly categorized as superconductors, conductors, and semiconductors, depending on their conducting carriers, resistance, and band structures. This research reports the discovery of super-semiconductors, whose resistivity is 3–10 orders of magnitude lower than conventional semiconductors at room temperature. In addition, there is a transition from a metal state to a super-semiconducting state at near room temperatures, which is accompanied by an increase in hole carrier density and the mobility increase in electrons. For the first time, a hole-dominated carrier metal is observed in nanostructured bimetallic arrays near room temperature, and no other special conditions are required. Such a behavior is due to the generation of hot electrons and holes induced by metal plasmon resonance in the infrared range in the nanostructured bimetallic arrays. Our research empowers metals with semiconductor features and paves the way to realize ultra-low-power metal-based semiconductor devices. [ABSTRACT FROM AUTHOR]

Ti(C,N)-TiB2 cermets were fabricated from Ti(C,N), TiB2, Co and WC powder mixtures via a vacuum hot pressing process. The influence of TiB2 content on their microstructures and mechanical properties was investigated. As a result of the elevated TiB2 contents, two types of core-rim microstructures were present in the Ti(C,N)-TiB2 cermets, and remarkably improved mechanical properties were achieved. With the increase of TiB2 content, the flexural strength, fracture toughness and hardness of the Ti(C,N)-TiB2 cermets first increased, and then decreased, while their relative density consistently decreased. Attributed to an integration of the intergranular and intrangranular fracture behaviors, the Ti(C,N)-TiB2 cermets with 20 wt% TiB2 content exhibited the best overall properties with the relative density, hardness, fracture toughness and flexural strength at 99.3%, 1 995 H V, 7.92 MPa·m1/2 and 1 114 MPa, respectively. The underlying mechanism for their enhanced properties was studied in detail. [ABSTRACT FROM AUTHOR]

ZrO2‐whisker‐reinforced Ti(C,N)‐based cermets were designed and prepared via a vacuum hot‐pressing process. The ZrO2 whisker characteristics and the phase, microstructure and mechanical properties of the cermets were investigated, and the relevant toughening mechanisms were examined. The results indicate that the ZrO2 whiskers retain their morphology and significantly improve the mechanical properties of the cermets. The relative density and hardness decreased slightly with increasing ZrO2 whisker content. At a whisker content of 7.5 wt.%, the fracture toughness and flexural strength reached their maximum values of 7.825 MPa·m1/2 and 1094 MPa, respectively. This enhancement in the mechanical properties is due to stronger bonding between the interfaces through dimples, tearing ridges and whisker pull‐out, in addition to the inhibition of crack propagation via crack deflection, crack branching and crack bridging. [ABSTRACT FROM AUTHOR]

A new porous material, alveolate Cu2−xSe microsheets, was synthesized through a simple one-step solvothermal process. The surface morphology and microstructure of the as-prepared Cu2−xSe were characterized by various techniques. It was found that the as-synthesized Cu2−xSe has hierarchical porosity composed of mesopores and macropores, and rich active surfaces of {111} facets. A noteworthy visible-light-responsive photocatalytic discoloration of Rhodamine B was observed for the as-developed alveolate Cu2−xSe microsheets. The superior photocatalytic properties demonstrated by the as-synthesized Cu2−xSe are mainly attributed to the highly accessible active surfaces of the {111} facets and the wider light absorption range resulting from its narrower band gap. [ABSTRACT FROM AUTHOR]

Developing high-capacity anodes is of great importance for the advancement of sodium ion batteries. In this work, we report a powerful combined method of plasma enhanced chemical vapor deposition–electrodeposition (PECVD–ED) to construct high-quality vertical graphene/MoO2 (VG/MoO2) core/shell arrays. The conductive MoO2 (n-type semiconductor) shell is uniformly electrodeposited on the VG core to form a binder-free integrated electrode. Compared with carbon fibre cloth-supported MoO2 film (CFC/MoO2), the obtained VG/MoO2 core/shell arrays display a higher surface area, better mechanical stability and improved electrical conductivity. Due to these positive advantages, the VG/MoO2 arrays show enhanced sodium ion storage performance with a reversible capacity of 678 mA h g−1 (vs. 542 mA h g−1 for CFC/MoO2) at the current density of 100 mA g−1, and a stable cycling life with a capacity retention of 81.7% (vs. 62.1% for CFC/MoO2) after 500 cycles. Our results provide a new route for the synthesis of high-capacity anodes for sodium ion batteries. [ABSTRACT FROM AUTHOR]

Recently, stripe antiferromagnetic spin fluctuations have been observed in SrCo2As2, which are similar to those found in AFe2As2 superconductors. It is interesting to tune the magnetic properties of this compound to induce superconductivity by chemical doping or applied pressure. Here we present careful chemical doping studies on SrCo2As2 by doping the element La on the Sr sites. We found that a dramatic alteration of the magnetic behavior (from paramagnetism to ferromagnetism) was induced by the incorporation of traces of La (2.5%). The results show that ferromagnetic order is preferred over A-type AFM or stripe-type AFM order when SrCo2As2 is electron-doped. On this basis, in order to regulate its magnetic ground state with the aim of inducing superconductivity, hole-doping may be superior to electron-doping. Furthermore, an unusual magnetic phase diagram between SrCo2As2 and LaCo2As2 is also presented in this work. [ABSTRACT FROM AUTHOR]

Lithium ions batteries (LIBs) with high power/energy densities largely rely on the innovation of electrode materials. Herein, for the first time, we rationally construct novel titanium niobium oxide (Ti2Nb10O29, TNO) nanospheres with a three-dimensional porous structure consisting of cross-linked nanoparticles by a simple solvothermal method combined with heat treatment. Compared to bulk TNO microrods, the obtained TNO nanospheres show a larger specific surface area and richer/shorter transfer channels for ions/electrons. Owing to these advantages, the TNO nanosphere electrode exhibits noticeable exceptional electrochemical performance with superior high-rate capability (241 mA h g−1 at 10C, and 208 mA h g−1 at 20C) and ultra-long life with a capacity of 215 mA h g−1 after 500 cycles at 10C, much better than the TNO microrod counterparts. Our findings may pave a new way for the design/fabrication of the state-of-the-art electrodes for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

The soft magnetic properties and giant magnetoimpedance (GMI) effect of the multilayered structure (F/SiO2)3/Ag/(SiO2/F)3 (F≡Fe71.5Cu1Cr2.5V4Si12B9) films, which were prepared by radio frequency sputtering without and with a longitudinal magnetic field of about 72 kA/m, are studied. The results show that the GMI effect almost cannot be detected in the samples deposited without field, whereas, a longitudinal magnetic field applied during deposition process obviously optimizes the soft magnetic properties of the films, and noticeable GMI effect is obtained. The maximum values of the longitudinal and transverse GMI ratios are 45% and 44% at the frequency of 6.81 MHz, respectively. In addition, the dependence of magnetoimpedance ratio, magnetoresistance ratio, magnetoreactance ratio and effective permeability ratio on the frequency has been investigated. We found that the GMI spectrum curves in the longitudinal and transverse cases almost overlap for the field-deposited sample. The GMI effect is mainly a giant magnetoinductive effect at low frequencies. When f >9 MHz, magnetoreactance ratio changes to a negative, i.e., the property of reactance changes from inductive to capacitive. [ABSTRACT FROM AUTHOR]

Simultaneously tuning light absorption wavelength and absorbance is a critical challenge in photoelectric detection, mimic of photosynthesis, and simulation of photoreceptors in some animals' retinas. Here, highly ordered hexagonal nanostructured Si arrays are fabricated using monolayer colloid crystal templates. A quantitative relationship between geometric size and light absorption is unveiled in the Si arrays, namely double‐quarter‐wavelength resonance (DQWR). Based on the DQWR model, the absorption wavelength can be readily tuned from 200 to 2400 nm, and the absorbance can be enhanced from ≈80% to above 99% in the full spectrum. Due to the hemisphere‐shell structural feature of the Si arrays, excellent omnidirectional antireflective performance can also be realized. Most importantly, the outstanding antireflection performance of the nanostructures is independent of the substrate. The results not only have important implications for understanding the antireflective mechanism of the nanostructured arrays, but also endow the approach promising in diverse applications, including biomimicry, antireflective film, infrared imagery, and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

Lamellar MoS 2 has attracted widespread attention as a potential electrocatalytic HER (Hydrogen evolution reaction) catalyst. However, it is difficult to further improve its catalytic activity due to two major drawbacks: the limited number of active sites and its poor conductivity. Here, we adopt a one-step method utilizing an ultrafast pulsed laser treatment to produce multiple decorations on lamellar MoS 2 , where nanocrystallization and amorphization of lamellar MoS 2 are achieved simultaneously, along with an additional characteristic of atomic steps. Due to this special microstructure, laser-treated MoS 2 exhibits excellent electrocatalytic performance with a low overpotential and a small Tafel slope (217 mV @ 10 mA cm−2 and 74.5 mV dec−1, respectively), which is superior to that of untreated lamellar MoS 2 (461 mV @ 10 mA cm−2 and 142.6 mV dec−1, respectively). The MoS 2 prepared in this way has a high catalytic activity and a high stability, which indicates potential for electrocatalysis applications. • We proposed a one-step method using ultrafast pulsed laser treatment to enhance the HER performance of lamellar MoS 2. • We prepared ultra-small MoS 2 nanoparticles, amorphization, and atomic steps in situ on lamellar MoS 2. • The performance of treated MoS 2 is far superior to that of MoS 2 before laser treatment. [ABSTRACT FROM AUTHOR]

Airy transform of Laguerre-Gaussian (LG) beams is investigated. As typical examples, the analytic expressions for the Airy transform of LG 01 , LG 02 , LG 11 , and LG 12 modes are derived, which are special optical beams including the Airy and Airyprime functions. Based on these analytical expressions, the Airy transform of LG 01 , LG 02 , LG 11 , and LG 12 modes are numerically and experimentally investigated, respectively. The effects of the control parameters α and β on the normalized intensity distribution of a Laguerre-Gaussian beam passing through Airy transform optical systems are investigated, respectively. It is found that the signs of the control parameters only affect the location of the beam spot, while the sizes of the control parameters will affect the characteristics of the beam spot. When the absolute values of the control parameters α and β decrease, the number of the side lobes in the beam spot, the beam spot size, and the Airy feature decrease, while the Laguerre-Gaussian characteristic is strengthened. By altering the control parameters α and β, the performance of these special optical beams is diversified. The experimental results are consistent with the theoretical simulations. The Airy transform of other Laguerre-Gaussian beams can be investigated in the same way. The properties of the Airy transform of Laguerre-Gaussian beams are well demonstrated. This research provides another approach to obtain special optical beams and expands the application of Laguerre-Gaussian beams.

Based on the second-order moments, an analytical and concise expression of the beam propagation factor of a hollow vortex Gaussian beam has been derived, which is applicable for an arbitrary topological charge $m$m. The beam propagation factor is determined by the beam order $n$n and the topological charge $m$m. With increasing the topological charge $m$m, the beam propagation factor increases. However, the effect of the beam order $n$n on the beam propagation factor is associated with the topological charge $m$m. By using the transformation formula of higher-order intensity moments, an analytical expression of the kurtosis parameter of a hollow vortex Gaussian beam passing through a paraxial and real $ABCD$ABCD optical system has been presented. The kurtosis parameter is determined by the beam order $n$n, the topological charge $m$m, and the position of observation plane $ \eta $η. The influence of the beam order $n$n on the kurtosis parameter is related with the topological charge $m$m and the position parameter $ \eta $η. When the beam order $n$n is larger than 1, the kurtosis parameter in different observation $\eta$η-planes decreases and tends to a stable value with increasing the topological charge $m$m. When $m = \pm {2}n$m=±2n, the kurtosis parameter is independent of the position parameter $ \eta $η and keeps unvaried during the beam propagation. Regardless of the values of $n$n and $m$m, the kurtosis parameter must tend to a saturated value or a stable value as the position parameter $ \eta $η increases to a sufficiently large value. This research is beneficial to the practical application of a hollow vortex Gaussian beam.

A series of β-FeSe nanorods composited g-C 3 N 4 were prepared. The structure, morphology, chemical state, photocatalytic activity, electrochemical impedance and photoluminescence of β-FeSe/g-C 3 N 4 composites were well characterized. It is found that the decolourization rate of 3 wt% β-FeSe/g-C 3 N 4 composites reaches 4.4 times than that of g-C 3 N 4 . The improved photocatalytic properties could be ascribed to the reduced recombination of photogenerated electrons and holes, which is derived from the excellent ability of β-FeSe to capture and transfer electrons. This work provides an alternative co-catalyst for decolourizing organic matter., Competing Interests: The authors declare no competing interests.

Noble metal-based catalysts are vital electrocatalysts for the oxygen evolution reaction (OER), which is a half reaction among multiple renewable energy-related reactions. To fully exploit their potential as efficient OER catalysts, we developed a fast one-step strategy to engineer a unique nanostructure for the benchmark catalyst IrO2 utilizing an ultra-fast pulse laser, through which a shell of ultra-small Ir spheres with a diameter of ca. 2 nm is in situ engineered around the IrO2 core. The creation of the Ir sphere shell not only increases the electrochemical surface area, but also improves the electrical conductivity of the electrocatalyst. The as-engineered IrO2@Ir architecture exhibits extremely high electrocatalytic activity towards the OER, revealing an overpotential of 255 mV at 10 mA cm-2 and Tafel slope of 45 mV dec-1. These values are much lower than those observed for the unmodified structure. Furthermore, the catalytic performance is the best among all the noble metal-based OER catalysts. This work may open a new avenue to efficiently improve the catalytic activity of noble metal-based catalysts and significantly advance the development in the energy industry.

Light reflection from surfaces is ubiquitous in nature. Diverse optoelectronic devices need durable, omnidirectional, and transparent ultra-antireflective surfaces. Here, we engineered antireflective transparent surfaces composed of silica nanocaps through a simple thermal treatment of a silica-coated monolayer colloidal crystal template. The relationship between the structure and the antireflective performance of the silica nanocaps was systematically studied both experimentally and numerically. On the basis of the understanding of the structure-antireflection relationships, ultra-antireflection coatings with a transmittance of ∼98.75 ± 0.15% in the visible wavelength range were prepared by fabricating two differently sized silica nanocaps. More importantly, the antireflection of the coatings formed by two differently sized nanocaps demonstrated poor dependence on the angle of the incident light (i.e., omnidirectionality). The reflection is <2.5% even at an incident angle of 60°. The prepared ultra-antireflective silica nanocap coatings outperform state-of-the-art transparent antireflective coatings regarding the antireflection performance, the wavelength range, and the omnidirectionality. The silica nanoshells were welded together with the underlying fused silica. Therefore, they can sustain common mechanical friction and scratching, demonstrating extraordinary mechanical durability as verified by sand abrasion tests. Further, the silanized silica nanocaps turned out to be hydrophobic with an outstanding self-cleaning performance without prominently influencing the transmittance. The durable and omnidirectional ultra-antireflective transparent silica nanocaps will have promising applications in solar energy conversion and storage, displays, optical lenses, and a wide range of optoelectronic devices.