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Silver nanocomposite coatings are prepared by the sol-gel method for the prevention of biofilm formation on the surface of medical implanted devices. High-temperature processing of such coatings can lead to diffusion of nanosilver and reduce the amount of available silver particles for long-term effects. Using a low-temperature sol-gel method, we have successfully prepared silane-based matrices, phenyltriethoxysilane (PhTEOS), containing different amounts of Ag nanoparticles. The incorporation of a silver salt into the sol-gel matrix resulted in a desired silver release rate, i.e. high initial release rate followed by a lower sustained release for more than 15 days, as determined by inductively coupled plasma mass spectrometry (ICP-MS). Scanning electron microscopy (SEM) has been employed to investigate the morphology of the film surfaces before and after immersion in a nutrient-rich bacterial suspension of approximately 108 CFU ml [?] 1, which was incubated for up to 30 days at 37 degC. It was found that thin films containing 35 nm particles could prevent the formation of biofilm for over 30 days. The presence of surface silver before and after 3, 9 and 15 days immersion was confirmed by x-ray photoelectron spectroscopy (XPS). [ABSTRACT FROM AUTHOR]

We report on the growth of high-aspect-ratio ({\gtrsim }300 ) zinc sulfide nanotubes with variable, precisely tunable, wall thicknesses and tube diameters into highly ordered pores of anodic alumina templates by atomic layer deposition (ALD) at temperatures as low as 75 degC. Various characterization techniques are employed to gain information on the composition, morphology and crystal structure of the synthesized samples. Besides practical applications, the ALD-grown tubes could be envisaged as model systems for the study of a certain class of size-dependent quantum and classical phenomena. [ABSTRACT FROM AUTHOR]

Previous studies on nanofluids have focused on spherical or long-fibre particles. In this work, a new type of complex nanoparticle-a hybrid sphere/carbon nanotube(CNT) particle, consisting of numerous CNTs attached to an alumina/iron oxide sphere-is proposed for applications in nanofluids. In such hybrid nanoparticles, heat is expected to transport rapidly from one CNT to another through the centre sphere and thus leading to less thermal contact resistance between CNTs when compared to simple CNTs dispersed in fluids. CNTs have an extremely high thermal conductivity, but thermal resistance between the CNTs and the fluid has limited their performance in nanofluids. The proposed hybrid sphere/CNT particles are synthesized by spray pyrolysis followed by catalytic growth of CNTs. The spheres are about 70 nm in diameter on average, and the attached CNTs have a length up to 2 µm. These hybrid nanoparticles are dispersed to poly-alpha-olefin with sonication and a small amount of surfactants to form stable nanofluids. The thermal conductivity of the fluids has been measured by a 3?-wire method over a temperature range 10-90?°C. The results indicate that the effective thermal conductivity of the fluids is increased by about 21% at room temperature for particle volume fractions of 0.2%. [ABSTRACT FROM AUTHOR]

Two-dimensional topological insulators (TIs) show great potential applications in low-power quantum computing and spintronics due to the spin-polarized gapless edge states. However, the small bandgap limits their room-temperature applications. Based on first-principles calculations, a series of C 2 X (X = H, F, Cl, Br and I) functionalized III-V monolayers are investigated. The nontrivial bandgaps of GaBi-(C 2 X) 2 , InBi-(C 2 X) 2 , TlBi-(C 2 X) 2 and TlSb-(C 2 X) 2 are found to between 0.223 and 0.807 eV. For GaBi-(C 2 X) 2 and InBi-(C 2 X) 2 , the topological insulating properties originate from the s-px,y band inversion induced by the spin-orbital coupling (SOC) effect. While for TlBi-(C 2 X) 2 and TlSb-(C 2 X) 2 , the topological insulating properties are attributed to the SOC effect-induced band splitting. The robust topological characteristics are further confirmed by topological invariants Z 2 and the test under biaxial strain. Finally, two ideal substrates are predicted to promote the applications of these TIs. These findings indicate that GaBi-(C 2 X) 2 , InBi-(C 2 X) 2 , TlBi-(C 2 X) 2 and TlSb-(C 2 X) 2 monolayers are good candidates for the fabrication of spintronic devices., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

MXene two-dimensional materials have been widely used in energy storage, catalysis, sensing and other fields, Nb 2 C as a typical two-dimensional MXene material, its exploration in the field of optoelectronics is still in its infancy, especially Nb 2 C-based photodetectors are still to be developed. This paper demonstrates that two-dimensional films based on few-layer Nb 2 C have a photoelectric response in the wavelength range from visible to near-infrared. We have found that the light response performance can be easily adjusted by controlling the thickness of the spin-coated film, and that Nb 2 C photodetectors show great advantages in terms of wide bandwidth, polarization response, high switching ratio, etc. By adjusting the material concentration and sample thickness, the photocurrent can reach up to 330 nA, the switching ratio can reach 410, and the responsivity can reach 8.3 × 10 -4 A W -1 . In the polarization characteristic test, an extinction ratio of 7.6 can be obtained. By adjusting the content of that doped MoS 2 quantum dot, the dark current can reach 7.6 × 10 -13 A, and the switching ratio can reach 3 × 10 5 , which can be increased by 700 times. The above results show that the few-layer Nb 2 C nanosheets can be used as optoelectronic detectors in the visible to near-infrared bands, which further broadens the application prospects of two-dimensional MXene., (© 2024 IOP Publishing Ltd.)

In order to solve the poor structural stability of graphene oxide (GO) membrane, a facile and effective cross-linking technology was employed to create a high-performance GO membrane. Herein, DL-Tyrosine/amidinothiourea and (3-Aminopropyl) triethoxysilane were used to crosslink GO nanosheets and porous alumina substrate, respectively. The group evolution of GO with different cross-linking agents was detected via Fourier transform infrared spectroscopy. Ultrasonic treatment and soaking experiment were conducted to explore the structural stability of the different membranes. The GO membrane cross-linked with amidinothiourea exhibits exceptional structural stability. Meanwhile, the membrane has superior separation performance, with the pure water flux reaching approximately 109.6 l·m -2 ·h -1 ·bar -1 . During the treatment of 0.1 g l -1 NaCl solution, its permeation flux and rejection for NaCl are about 86.8 l·m -2 ·h -1 ·bar -1 and 50.8%, respectively. The long-term filtration experiment also demonstrates that the membrane exhibits great operational stability. All these indicate the cross-linking graphene oxide membrane has promising potential applications in water treatment., (© 2023 IOP Publishing Ltd.)

γ -graphdiyne ( γ -GDY) is a new two-dimensional carbon allotrope that has received increasing attention in scientific and engineering fields. The mechanical properties of γ -GDY should be thoroughly understood for realizing their practical applications. Although γ -GDY is synthesized and employed mainly in their bilayer or multilayer forms, previous theoretical studies mainly focused on the single-layer form. To evaluate the characteristics of the multilayer form, the mechanical properties of the bilayer γ -GDY ( γ -BGDY) were tested under uniaxial tension using the molecular dynamics simulations. The stress-strain relation of γ -BGDY is highly temperature-dependent and exhibits a brittle-to-ductile transition with increasing temperature. When the temperature is below the critical brittle-to-ductile transition temperature, γ -BGDY cracks in a brittle manner and the fracture strain decreases with increasing temperature. Otherwise, it exhibits ductile characteristics and the fracture strain increases with temperature. Such a temperature-dependent brittle-to-ductile transition is attributed to the interlayer cooperative deformation mechanism, in which the co-rearrangement of neighboring layers is dominated by thermal vibrations of carbon atoms in diacetylenic chains. Furthermore, the brittle-to-ductile transition behavior of γ -BGDY is independent of loading direction and loading rate. The ultimate stress and Young's modulus decrease at higher temperatures. These results are beneficial for the design of advanced γ -GDY-based devices., (© 2022 IOP Publishing Ltd.)

Designing in-plane supercapacitors with high electrode materials selectivity is an indispensable approach to improve electrochemical performance. In this work, a facile template method was employed to fabricate in-plane supercapacitors. This template method could select any electrochemical active materials as electrode materials of in-plane supercapacitors. Hence, a high electrochemical performance material Mn-Co LDO-2S with optimized metal-sulfur bonds proportion and abundant sulfur vacancies was employed as electrode material of symmetrical in-plane supercapacitor (SPS). SPS exhibits excellent electrochemical performance finally, and has considerable area energy density 55.0 μ Wh cm -2 with an area power density of 0.7 mW cm -2 . As a result, introducing sulfur atoms and sulfur vacancies are efficient approaches to improve electrode materials' electrochemical performance, and template method that proposed in this work is a promising approach to widen selectivity of in-plane supercapacitors' electrode materials., (© 2022 IOP Publishing Ltd.)

Substitution of commercial Pt/C electrocatalysts with efficient carbon-based ones for oxygen reduction reaction (ORR) still remains a huge challenge. For practical ORR applications it is significant to design robust 3D network nanostructures in that they do not require polymer binders. For conventional powder catalysts, they must be combined with substrate, leading to their shedding and degradation. In this work, vertically-aligned N-doped carbon nanowalls/diamond (N-CNWs/D) films are synthesized by means of a microwave plasma chemical vapor deposition technique, where nitrogen doping is conducted during the growth process and a subsequent facile annealing treatment under Ar atmosphere. The obtained Ar treated N-CNWs/D film exhibits an ORR onset potential of 835 mV (versus reversible hydrogen electrode) in 0.1 mol l -1 KOH solution in a four-electron reaction pathway. It also displays excellent tolerance toward methanol crossover and long-term stability (e.g. a current density loss of only 10% even after 16 h measurement). The boosting ORR performance can be attributed to the activated pyridinic N dopant at abundant edge sites and enlarged electrochemical surface areas of N-CNWs/D films. This work not only develops a controllable strategy to fabricate binder-free carbon-based ORR electrocatalysts, but also paves a way to in-depth understand actual active sites in terms of ORR pathway mechanisms., (© 2021 IOP Publishing Ltd.)

The acquired drug resistance of the platinum-based drug is a main obstacle in cancer therapy. Herein, an aminopyrrolic receptor 1 was synthesized to sensitize satraplatin for overcoming the drug resistance as well as improving tumor targeted ability. Thus, Pluronic F127-based polyaniline nanoparticles were designed to co-deliver satraplatin and aminopyrrolic receptor 1, which could control the drug release with the Near Infrared laser irradiation (808 nm) due to the polyaniline mediated photothermal conversion. Biological evaluation shows prepared nanoparticles (Pt-ARNPs) exhibited more effective cytotoxicity (IC 50  = 2.7 μ M) against the tested cancer cell lines under laser irradiation, compared with free satraplatin or treatment without Near-infrared radiation. Moreover, Pt-ARNPs showed comparable cytotoxicity against A549 and A549/cis cells, implying that the combination of satraplatin and aminopyrrolic receptor 1 with nano carrier might be a promising strategy to reduce platinum resistance and improve therapeutic effect in cancer therapy., (© 2021 IOP Publishing Ltd.)

In this work, the electrical properties of monolayer α -GeTe (ML α -GeTe) based on first-principles were studied, in which armchair α -GeTe shows an ohmic current-voltage relationship and zigzag α -GeTe shows an obvious nonlinear current. The potential distribution and band structure explain the mechanism for the anisotropy and nonlinearity. Then, based on calculation of the binding energy and Mulliken population, eight interface structures between graphene (GR) and ML α -GeTe were constructed, in which GC3 and TC3 were found to be relatively stable. Next, GR/ML α -GeTe/GR was established based on the two interfaces (GC3 and TC3). The current-voltage ( IV ) characteristics were calculated to show that the device has bipolar resistance characteristics, suitable set and reset voltages and a high window value (10 4 ). Further analysis of electron density inferred that the resistance mechanism was based on the drift of Te vacancies forming conductive filaments. And the performance of GR/ML α -GeTe/GR was found to be improved by the creation of Te vacancies. This work indicates that GR/ML α -GeTe/GR has the potential to be used to build resistive random access memory (RRAM) with good performance and may be instructive and valuable for the manufacture and application of RRAM., (© 2021 IOP Publishing Ltd.)

InGaAs/graphene Schottky photodiode has a low Schottky barrier height (SBH) which induces high dark current density. In this paper, an Al 2 O 3 thin film is inserted between the layer of InGaAs and graphene to suppress the dark current density for nearly two orders of magnitude. As a result, it is a distinct enhancement on the performance that the graphene/Al 2 O 3 /InGaAs near-infrared photodetector (NIR PD) under -0.4 V has a better responsivity of 523.77 mA W -1 and a better detectivity of 4.42 × 10 10 cm Hz 1/2 /W to 1064 nm incident light than the graphene/InGaAs NIR PD. Moreover, graphene/Al 2 O 3 /InGaAs NIR PD also has a great response to 1550 nm incident light and the degradation on the device was observed. With the calculation, an increase of 0.122 eV on the Schottky barrier height (SBH) of graphene/Al 2 O 3 /InGaAs was founded. The result is expected to promote the application of the graphene NIR PD to the novel sensors., (© 2021 IOP Publishing Ltd.)

In this work, a graphene (GR)/MoS 2 /GR selector was proposed based on first principle calculations. First, MoS 2 was chosen as the resistive switching layer due to its high carrier mobility and was doped with nine kinds of dopants. Semiconductor characteristics were still maintained with P, Si, and Ti doping, while the others showed semimetallic properties. Then, heterostructures were built between metal GR and MoS·X (X = S, P, Si, Ti), and the conductivities of MoS·Si and MoS·Ti were obviously improved with the GR electrode through analysis of the impurity orbital contribution to the band energy. The plane average electrostatic potential and the charge density difference show that the Schottky barrier height and width of the GR/MoS·Si interface were the smallest and that the intensity of the built-in electric field was better than that of GR/MoS 2 and GR/MoS·Ti. Finally, GR/MoS·X(X = S, Si, Ti)/GR selectors were proposed, and the electronic transmission shows that the ON-state current (I on ) and nonlinear coefficient of the GR/MoS·Si/GR selector were increased by two and three orders of magnitude, respectively, and the threshold voltage (V th ) was reduced by approximately 1 V, which can better suppress the leakage current in a one-selector one-RRAM cross array. This work may be instructive and valuable for the design and optimization of GR/MoS 2 /GR selectors.

Carbonized polymer dots (CPDs), as a novel fluorescent material, have broad application prospects in the fields of bio-imaging, bio-sensors, disease diagnosis and photovoltaic devices due to their low cost, low toxicity, easy modification and little environmental impact. In this paper, folic acid (FA) modified CPDs (FA-CPDs) are synthesized from p-Phenylenediamine (p-PD) and FA molecules using a traditional one pot hydrothermal reaction in order to detect cancer cells containing a folate receptor (FR). The synthesized FA-CPDs were characterized by transmission electron microscopy, Fourier transfrom infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, UV-vis and fluorescence techniques. The red fluorescence emission is realized by doping phosphorus atoms into the carbonized polymer. Upon excitation at 513 nm, the maximum emission wavelength of FA-CPDs aqueous solution was obtained at 613 nm. Moreover, the as-prepared FA-CPDs exhibit excellent excitation-independent behavior and good stability with high quantum yield (QY) at about 30.6%. The binding of FA-CPDs with FRs on cancer cells produces target recognition and enters the cells through endocytosis. Additionally, it is worth noting that FA-CPDs have good biocompatibility and imaging in HeLa cells has been successfully achieved. Therefore, our FA-CPDs have potential applications as biocompatibility probes for cancer diagnosis and treatment.

A ceramic in polymer hybrid solid electrolyte (HSE) based on a poly vinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer comprising Na 3 Zr 2 Si 2 PO 12 (NASICON) ceramic particles was prepared by a simple solution casting method followed by activation in a liquid electrolyte. The prepared HSE exhibits good flexibility, high ionic conductivity of 2.25 × 10 -3 S cm -1 at room temperature (RT), and good interface stability. The carbon coated sodium vanadium phosphate (Na 3 V 2 (PO 4 ) 3 /C) cathode was synthesized by the sol-gel method and assembled into batteries with different electrolytes. The batteries based on HSE exhibit better electrochemical performance than that of NASICON ceramic solid electrolytes, which delivers a reversible capacity of 98 mAh · g -1 at 0.2 C and exhibits good capacity retention of 85% after 175 cycles at 0.5 C. Not only does the HSE inherit great flexibility, but also exhibits good interfacial contact with electrodes. The schematic diagram of Na-ion conductivity in ceramic, polymer and HSE was illustrated to demonstrate the sodium ion transport mechanism. The HSE with high ionic conductivity and good flexibility for interfacial contact with electrodes shall provide a designing strategy for different solid-state batteries.

Cosmetic brush-like Co 3 O 4 nanowires grown on carbon cloth were prepared by regulating the addition of trisodium citrate by hydrothermal synthesis. Then a simple liquid-phase ion exchange was carried out to improve the electrochemical performance of Co 3 O 4 by surface modification with Ni 2+ . After surface modification, at a current density of 4 A g -1 , the specific capacity significantly increased from 276.1 C g -1 (720.5 F g -1 ) to 655.9 C g -1 (1525.4 F g -1 ). Meanwhile, the electrocatalytic oxidation performances of methanol and urea were also improved significantly. The enhanced electrochemical properties were attributed to the modification of the surface of Co 3 O 4 with Ni 2+ .

Recently, two-dimensional (2D) monolayers C 3 B and C 3 N attract growing research interest due to the excellent physical properties. In this work, the thermal conductivities (k) of the monolayer C 3 B x N 1-x alloy and the special C 3 B 0.5 N 0.5 superlattice (C 3 B 0.5 N 0.5 -SL) alloy are systematically evaluated by using molecular dynamic simulation. First, the k of monolayer C 3 B x N 1-x alloy presents a U-shaped profile with the increasing random doping ratio (x), in which the lowest k exists in x = 0.5. Second, we further calculate the thermal conductivity of C 3 B 0.5 N 0.5 -SL. The result shows an initial decreasing and then rising trend, and the coherent length is 5.11 nm which occupies the minimum thermal conductivity. Furthermore, to uncover the phonon thermal transport mechanism, we calculate the spatiotemporal thermal transport, phonon density of states, phonon group velocity, participation ratio and the phonon wave packet simulations in monolayer alloy system. We note that on account of the random doping atoms, the enhancive phonon-impurity scattering and phonon localization reduce the thermal conductivity in monolayer C 3 B x N 1-x alloy. In C 3 B 0.5 N 0.5 -SL, when the period length is smaller than the coherent length, coherent phonon modes emerge because of the phonon interference, in which the superlattice can be regarded as a 'newly generated material'. However, when the period length is larger than the coherent length, the decreasing number of the interface in superlattice lessens phonon-interface scattering and cause the increasing thermal conductivity. This work contributes the fundamental knowledge for thermal management in 2D monolayer C 3 B x N 1-x alloy based nanoelectronics.

As a novel class of two-dimensional materials, MXene has provoked tremendous progress for various applications in functional devices. Here, we pioneer a preliminary understanding on the field emission behavior of MXene for the first time. Ti 3 C 2 paper is fabricated by using facile filtration method, and multiple vertical sheets appear on the surface of MXene paper with high electrical conductivity (2.93 × 10 5 S m -1 ) and low work function (3.77 eV). The field electron emission performance and electric field distribution on MXene emitters are measured and simulated under planar and standing conditions. Both emitter conditions exhibit stable, uniform electron emission pattern, and the standing emitter achieves high emission current density of 59 mA cm -2 under 7.5 V μm -1 . This work demonstrates the feasibility of MXene as cold electron source, establishing a preliminary foundation for its applications in field emission-based devices.

High-efficiency and low-cost electrocatalysts are generally believed to be the critical factor and have been highly researched to catalyze the oxygen reduction reaction (ORR) during the operation of Li-O 2 battery (LOB). The catalysts with better ORR performance are essential for high-performance LOBs. Herein, a binder-free MnO x @carbon cloth cathode composed of Mn 3 O 4 nanoparticles and Mn 2 O 3 nanosheets were directly synthesized on the carbon cloth by electrodeposition and subsequently heat treatment at different temperature (from 200 °C to 400 °C). With the increase of temperature, the Mn 3 O 4 nanospheres gradually transformed into Mn 2 O 3 nanosheets. The MnO x obtained at 350 °C exhibited the best ORR performance. And MnO x -350 °C could operate more than 80 cycles at 340 mA g -1 with a limiting specific capacity of 1000 mAh g -1 , and its first discharge specific capacity could nearly achieve 8000 mAh g -1 at 200 mA g -1 .

In this work, we first report Au nanoclusters/porous silica particles nanocomposites as fluorescence enhanced sensors for selective and sensitive detection of Cu (II). As red-emitting GSH-protected Au nanoclusters (Au NCs) were self-assemble into porous silica particles (PSPs) after ultrasonic treatment. As a result, the Au NCs can be immobilized in the nano-channels of PSPs, which leads to the observation of an immobilized induced emission enhancement phenomenon. The photoluminscence (PL) intensity of the nanocomposites can enhance dozens of times compared with Au NCs. As a result, we obtain a novel PL enhanced sensor of Au NCs/PSPs nanocomposites with excellent PL properties. The as-prepared Au NCs/PSPs nanocomposites show good water-solubility, high stability, low toxicity, and exhibit a high PL quenching for reliable, sensitive and selective detection of Cu 2+ . The limit of detection can reach as low as 1 ppb. What is more, the Au NCs/PSPs nanocomposites also show sensitive detection of Cu 2+ in living cells. These properties provide the Au NCs/PSPs nanocomposites with promising PL sensors for Cu 2+ detection in various environmental and biological systems.

Circulating tumor cells (CTCs) are a type of rare cell that are firstly shed from solid tumors and then exist in the bloodstream. The effective capture and separation of CTCs has significant meaning in cancer diagnosis and prognosis. In this study, novel Fe 3 O 4 -FePt magnetic nanocomposites (Fe 3 O 4 -FePt MNCs) were constructed by integrating face centered cubic (fcc) FePt nanoparticles (NPs) onto the surface of the Fe 3 O 4 @SiO 2 core. After further modification with NH 2 -PEG-COOH and the tumor-targeting molecule tLyP-1, the acquired Fe 3 O 4 -FePt MNCs possesses excellent biocompatibility and stability and could efficiently target and capture tLyP-1 receptor-positive CTCs. Based on the acidic microenvironment within cancer cells, the FePt layer could rapidly release active Fe 2+ ions, which could catalyze H 2 O 2 into reactive oxygen species (ROS) and further induce in situ apoptosis in cancer cells while having no distinct cytotoxicity to normal cells. Moreover, the Fe 3 O 4 @SiO 2 core with its intrinsic magnetism has huge potential for the bioseparation of CTCs. The in vitro ROS fluorescence imaging experiments and cell capture and separation experiments indicated that the Fe 3 O 4 -FePt MNCs could specifically capture and separate cancer cells in the CTCs model and further induce in situ apoptosis. Therefore, the Fe 3 O 4 -FePt MNCs could serve as a promising multifunctional nanoseparator for efficiently capturing CTCs and simultaneously inducing in situ chemotherapy.

This paper presents multi-walled carbon nanotube (MWCNT)/poly(m-phenylene isophthalamide) (PMIA) nanocomposite films as electrothermal elements, which offer advantages in flexibility, low energy consumption and rapid temperature growth. The electrical properties, electrothermal behavior and thermal stability of the films were investigated as a function of MWCNT content. The percolation behavior analysis revealed MWCNTs built a continuously conductive network in PMIA matrix at the corresponding percolation threshold of ∼0.06 wt%. The electrothermal behavior of the MWCNT/PMIA film was investigated by considering temperature response rapidity and electrothermal efficiency under different ambient conditions. For the film with 7.0 wt% MWCNTs under different ambient conditions, the film worked at a high heating rate of 1.0-8.2 °C s -1 and cooling rate of 0.75-7.0 °C s -1 under a low voltage of 3-12 V, due to the low electrical resistivity (4.5 Ω cm) of the film. The prepared MWCNT/PMIA films supported more outstanding heating performance than conventional PI-Kanthal film, including good heating uniformity, higher electrothermal efficiency and heating/cooling rate. Moreover, the improved thermomechanical properties of the nanocomposite were observed by dynamic thermomechanical analysis.

Black phosphorus (BP) has recently drawn great attention in the field of electrocatalysis due to its distinct electrocatalytic activity for the oxygen evolution reaction (OER). However, the slow OER kinetics and the poor environmental stability of BP seriously limits its overall OER performance and prevents its electrocatalysis application. Here, sulfur (S)-doped BP nanosheets, which are prepared using high-pressure synthesis followed by liquid exfoliation, have been demonstrated to have much better OER electrocatalytic activity and environmental stability compared to their undoped counterparts. The S-doped BP nanosheets display a Tafel slope of 75 mV dec -1 , which is a favorable value refered to the kinetics of OER in electrochemical tests. Notably, there is no degradation of S-doped BP nanosheets after six days exposure to ambient, indicating an excellent environmental stability of the S-doped BP. The density functional theory calculations show that the OER activity of BP originate from its crystal defects and heteroatom S doping can effectively enhance its OER activity and stability. These results highlight the doping effect on electrocatalytic activities and stability of BP and provide a simple and effective method to design highly efficient OER catalysts based on the modification of BP.

Foodborne pathogens are perpetual threats to human and animal health. Detection of pathogens requires accurate, sensitive, rapid and point-of-care diagnostic assays. In this study, we described a simple and sensitive electrochemiluminescent (ECL) assay to detect the deadly bacteria Escherichia coli O157:H7 by [Formula: see text]-coated ZnO nanorods arrays (NAs). The [Formula: see text]-coated ZnO NAs were fabricated by immobilizing [Formula: see text] on ZnO NAs with a large specific surface area and good conductivity. An [Formula: see text]-2-(dibutylamino)-ethanol (DBAE) system coated on ZnO NAs exhibits high ECL intensity, rapid response and good stability. This system was further developed as an ECL immunosensor used in the detection of E. coli O157:H7. The proposed ECL immunosensor exhibits a broad detection range within the scope of 200-100 000 CFU ml -1 and quite a low detection limit of 143 CFU ml -1 . The high specificity, remarkable reproducibility and good stability offer a sensitive, selective, and convenient pathway for detecting E. coli O157:H7 in the field of food safety and clinical diagnosis.

The assembly of metal nanoparticles (NPs) can regulate their plasmon resonance properties to pursue the best properties for applications. However, the controllable assembly of large-scale metal NP cluster arrays remains a significant challenge. This paper presents a novel strategy to prepare large-scale Au NP cluster arrays based on colloidal lithography and template-guided self-assembly technique. The NPs arrays are fabricated by introducing Au NPs onto the quaternized poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brush templates via electrostatic interaction. The number of Au NPs in cluster can be arbitrarily tuned by changing the surface area of the polymer templates created by colloidal lithography, which resulted in tunable plasmonic properties. The prepared Au NP cluster arrays were used for surface enhanced Raman scattering (SERS) and the SERS properties of the Au NP cluster arrays were studied.

Cluster-assembled SmCo alloy films were prepared by low energy cluster beam deposition. The structure, magnetic domain, magnetization, and magnetostriction of the films were characterized. It is shown that the as-prepared films are assembled in compact and uniformly distributed spherical cluster nanoparticles, most of which, after vacuum in situ annealing at 700 K, aggregated to form cluster islands. These cluster islands result in transformations from superparamagnetic states to magnetic single domain (MSD) states in the films. Such MSD structures contribute to the enhanced magnetostrictive behaviors with a saturation magnetostrictive coefficient of 160 × 10 -6 in comparison to 105 × 10 -6 for the as-prepared films. This work demonstrates candidate materials that could be applied in nano-electro-mechanical systems, low power information storage, and weak magnetic detecting devices.

Gas sensing for hydrothermal synthesized SnO 2 -based gas sensors can be enhanced in three ways: structural improvement, composition optimization, and processing improvement. There have been zero-dimensional, one-dimensional, and three-dimensional structures reported in the literature. Controllable synthesis of different structures has been deployed to increase specific surface area. Change of composition would intensively tailor the SnO 2 structure, which affected the gas-sensing performance. Furthermore, doping and compounding methods have been adopted to promote gas-sensing performance by adjusting surface conditions of SnO 2 crystals and constructing heterojunctions. As for processing area, it is very important to find the optimal reaction time and temperature. In this paper, a gas-solid reaction rate constant was proposed to evaluate gas-sensing properties and find an excellent hydrothermal synthesized SnO 2 -based gas sensor.

Ag 2 WO 4 is a significant photocatalyst that responds to UV light irradiation only, which greatly hinders it for further practical application for solar light. To address this problem, herein, 1D plasmonic Ag/Ag 2 WO 4 photocatalysts have been fabricated by a successive process including hydrothermal synthesis to obtain Ag 2 WO 4 followed by an additional in situ chemical-reduction process for Ag decoration. Then, the structural features, optical properties, and electronic structures of Ag 2 WO 4 and Ag/Ag 2 WO 4 nanowires were systematically investigated via a combination of theoretical calculations and experimental evidence. The plasmon-enhanced Ag/Ag 2 WO 4 nanowires exhibited higher visible-light-driven photocatalytic activity, which performed a desired photodestruction ratio of 91.2% on methylene blue within 60 min and good stability in five cycles. The Ag decoration greatly facilitates visible-light harvesting and thus promotes photogenerated radical oxidation to dye, which is evidenced by the higher hydroxyl radical level of Ag/Ag 2 WO 4 detected in the ESR test during the photocatalytic process. The theoretical calculation based on density functional theory indicates that Ag nanoparticles formed on the surface of Ag 2 WO 4 could narrow the band gap of Ag 2 WO 4 . In addition, the surface plasmon resonance absorption effect and fast charge transfer effect in the metal-semiconductor system contribute to the photocatalytic performance of Ag/Ag 2 WO 4 .

The emergence of antibiotic resistance has resulted in increasing difficulty in treating clinical infections associated with biofilm formation, one of the key processes in turn contributing to enhanced antibiotic resistance. With the rapid development of nanotechnology, a new way to overcome antibiotic resistance has opened up. Based on the many and diverse properties of MoS 2 nanosheets that have attracted wide attention, in particular their antibacterial potential, herein, a novel antimicrobial agent to combat resistant gram-positive Staphylococcus aureus and gram-negative Salmonella was prepared using chitosan functionalized MoS 2 nanosheets loading tetracycline hydrochloride drugs (abbreviated to CM-TH). The antibacterial and anti-biofilm activities of the CM-TH nanocomposites showed the synergetic effect that the combination of nanomaterials and antibiotics was more efficient than either working alone. In particularly, the minimum inhibitory concentration values generally decreased by a factor of dozens, suggesting that CM-TH may become a possible alternative to traditional antibiotics in disrupting biofilms and overcoming antibiotic resistance in treating medical diseases.

The degree of crumpling affects the optoelectronic properties of graphene, which are very important for the performance of graphene-based devices and materials. In this article, we report an approach to tune the formation of wrinkles on single-layer graphene (SLG) by silicon nanopillar (SNP) arrays. By using gold nanoparticles as an etching mask, SNP arrays with different heights could be prepared by tuning the duration of etching. The formation of wrinkles on these SNP arrays was studied systematically. We found that thermal treatment could lead to a wrapping behavior of graphene around SNP arrays, which was accompanied by the emergence of many more wrinkles. Controllable wettability, conductivity and transmittance were demonstrated. This ability to tune wrinkles using SNP arrays can be employed to engineer the fabrication of graphene-related devices and other optoelectronic applications.

In this paper, a facile synthesis of carbon quantum dots (CQDs) and its field emission performance are reported. The CQDs are prepared from a single N, N-dimethylformamide acting as carbon and nitrogen-doping sources simultaneously. The CQDs are investigated by photoluminescence, transmission electron microscopy and x-ray photoelectron spectroscopy. The CQDs have an average size of 3 nm and are doped with N atoms. CQD dispersion shows strong fluorescence under UV illumination. For the first time, the field emission behavior of CQDs coated on Si substrate is studied. As a candidate of cold cathode, the CQDs display good field emission performance. The CQD emitter reaches the current density of 1.1 mA cm(-2) at 7.0 V μm(-1) and exhibits good long-term emission stability, suggesting promising application in field emission devices.

Gold nanorods (GNRs) attract extensive attention in current diagnostic and therapeutic applications which require the synthesis of GNRs with high yields, adjustable aspect ratio, size monodispersity, and easy surface decoration. In the seed-mediated synthesis of GNRs using cetyl trimethyl ammonium bromide (CTAB) micelles as templates, the additives of aromatic compounds have been found to be important for improving the size monodispersity of the as-synthesized GNRs; this is hopeful in terms of the further optimization of the synthetic methodology of GNRs. In this work, resveratrol, a natural polyphenol in grapes with an anti-oxidization behavior, is employed as the reductant for the seedless synthesis of GNRs with a good size monodispersity and a tunable aspect ratio. Accordingly, the longitudinal localized surface plasmon resonance (LSPR) peak is tunable from 570 to 950 nm. The success of our approach is attributed to the aromatic structure and mild reducibility of resveratrol. The embedment of resveratrol into CTAB micelles strengthens the facet-selective adsorption of CTAB, and therewith facilitates the anisotropic growth of GNRs. In addition, the mild reducibility of resveratrol is capable of supporting GNR growth by avoiding secondary nucleation, thus allowing the seedless synthesis of GNRs with a good size monodispersity. As a chemopreventive agent, the combination of resveratrol in GNR synthesis will consolidate the theranostic applications of GNRs.

This work aims to simplify multi-dimensional femtosecond transient absorption microscopy (TAM) data into decay associated amplitude maps (DAAMs) that describe the spatial distributions of dynamical processes occurring on various characteristic timescales. Application of this method to TAM data obtained from a model methyl-ammonium lead iodide (CH3NH3PbI3) perovskite thin film allows us to simplify the data set comprising 68 time-resolved images into four DAAMs. These maps offer a simple means to visualize the complex electronic excited-state dynamics in this system by separating distinct dynamical processes evolving on characteristic timescales into individual spatial images. This approach provides new insight into subtle aspects of ultrafast relaxation dynamics associated with excitons and charge carriers in the perovskite thin film, which have recently been found to coexist at spatially distinct locations.

We have demonstrated a novel three-dimensional (3D) architecture of a graphene/carbon nanotube (G-CNT) hybrid synthesized at large scale within just 5 s via a simple microwave-heating method without the usage of any other conducting or expanding agent for the first time. The carbon composites obtained consist of evenly grown CNTs with an average diameter of about 15 nm on the surface of graphene nanosheets. The G-CNT hybrid exhibits enhanced electrochemical performance for both aqueous and organic supercapacitor devices. Particularly, the G-CNT electrodes demonstrate an enhanced specific capacitance of 361 F g(-1) at a current density of 1.1 A g(-1) in an aqueous electrolyte and a volumetric capacitance of 254 F cm(-3) in an organic electrolyte. They also display excellent cycle stability with nearly 91.2% of the initial capacitance retained after 10 000 charging-discharging cycles at a current density of 15 A g(-1). This demonstrates that the developed composites have potential applications in supercapacitors and other energy storage devices.

Few-layer black phosphorus (BP) has attracted much attention due to its high mobility and suitable band gap for potential applic5ations in optoelectronics and flexible devices. However, its instability under ambient conditions limits its practical applications. Our investigations indicate that by passivation of the mechanically exfoliated BP flakes with a SiO2 layer, the fabricated BP field-effect transistors (FETs) exhibit greatly enhanced environmental stability. Compared to the unpassivated BP devices, which show a fast drop of on/off current ratio by a factor of 10 after one week of ambient exposure, the SiO2-passivated BP devices display a high retained on/off current ratio of over 600 after one week of exposure, just a little lower than the initial value of 810. Our investigations provide an effective route to passivate the few-layer BPs for enhancement of their environmental stability.

In this paper, we demonstrate a responsive etalon fabricated through combining colloidal lithography and surface-initiated atom-transfer radical polymerization (SI-ATRP). The responsive etalon is simply constructed with one responsive spacer sandwiched by two reflective layers, and the middle responsive spacer is constructed by grafting thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) brushes on a SiO2 nanosphere array. The etalon possesses one single interference peak in the visible region, and the interference peak changes sensitively against the concentration of the external stimulant (water vapor) or the temperature of the system, owing to the responsiveness of the PNIPAM brush. Importantly, the as-prepared etalon shows a rapid response rate and excellent stability, and it is also handy to realize the miniaturization and integration of the responsive etalon based on a conventional micro-fabrication method. These features all make the as-prepared responsive etalon an attractive candidate for future sensing applications. We believe such responsive etalons are promising for the fabrication of smart photonic materials and optical sensors that may be useful in tissue engineering, medical diagnosis, public security, and biochip areas.

Freestanding polyaniline (PANI) nanorods grown in situ on microwave-expanded graphene oxide (MEGO) sheets were prepared through a facile solution method. The morphological characterization indicates that large quantity of free-standing PANI nanorods with average diameter of 50 nm were uniformly deposited onto the double sides of the MEGO nanosheets to form a sandwich structure. The hybrid of PANI/MEGO (GPANI) exhibit high specific surface area and high electrical conductivity, compared with pristine PANI nanorods. When evaluated as electrodes for supercapacitors, the GPANI demonstrate high specific capacitance of 628 F g(-1) at a current density of 1.1 A g(-1), high-rate performance, and excellent cycle stability compared to individual component. Such excellent electrochemical performance should be attributed to the combined double-layer capacitance and pseudo -capacitance mechanisms from the MEGO sheets and PANI nanorods.

In this study, two cholesterol derivatives, (4-cholesterocarbonyl-4'-(N,N,N-triethylamine butyloxyl bromide) azobenzene (CAB) and 4-cholesterocarbonyl-4'-(N,N-diethylamine butyloxyl) azobenzene (ACB), one of which is positively charged while the other is neutral, were synthesized and incorporated with phospholipids and cholesterol to form doxorubicin (DOX)-loaded liposomes. PEGylation was achieved by including 1,2-distearoyl-sn-glycero-3-phosphatiylethanol-amine-N-[methoxy-(polyethylene glycol)-2000 (DSPE-PEG2000). Our results showed that PEGylated liposomes displayed significantly improved stability and the drug leakage was decreased compared to the non-PEGylated ones in vitro. The in vivo study with rats also revealed that the pharmacokinetics and circulation half-life of DOX were significantly improved when liposomes were PEGylated (p < 0.05). In particular, the neutral cholesterol derivative ACB played some role in improving liposomes' stability in systemic circulation compared to the conventional PC liposome and the positively charged CAB liposome, with or without PEGylation. In addition, in the case of local drug delivery, the positively charged PEG-liposome not only delivered much more of the drug into the rats' retinas (p < 0.001), but also maintained much longer drug retention time compared to the neutral PEGylated liposomes.

The study of the preparation and application of ZnS nanoparticles (NPs) has been one of the most prominent hotspots in the domain of semiconductor NPs. The ZnS NPs usually exist in two crystallographic forms: zinc blende (cubic) and wurtzite (hexagonal). However, controlled preparation of ZnS NPs with specified crystallographic forms is still a difficult problem. Herein, zinc blende type ZnS NPs have been prepared by coordination control with diethanolamine (DEA) in ethylene glycol (EG). The prepared ZnS NPs can be well dispersed in EG without precipitation. The effect of DEA on the crystal form of the ZnS NPs was studied. We conclude that in EG, when no strong coordinating agent exists for the zinc ion, hexagonal crystal ZnS nanoparticles may be obtained, while coordinating agents such as acetate and DEA coordinated with the zinc(II) ion can inhibit the formation of the hexagonal ZnS crystal nucleus and the more stable zinc blende can be obtained. Moreover, transparent nanocomposite coatings of ZnS in PU matrix were prepared. This demonstrates that the incorporation of ZnS NPs can improve the refractive index of the optical coatings.

A method for fabricating nanocrescent structures is presented based on a combination of colloidal lithography and parallel imprinting. In this process, non-close-packed colloidal spheres were prepared by a simple lift-up soft lithography technique, and subsequently the individual particles were used as shadow masks to angle deposit a layer of silver on the silicon substrates. Then, the silver-coated samples were etched to get silicon crescent nanohole arrays, which served as templates to mold patterned photocurable resin membranes. The patterned photocurable resin membranes were used to print gold nanocrescent nanostructures onto glass substrates. The size of the opening and the width of the gold nanostructures could be freely adjusted by changing the azimuth angle and tilt angle. Very importantly, the central angle of the nanocrescents could be adjusted in the range of 0°-360°. This method provides a low-cost and highly reproducible way to prepare complex nanostructure arrays for applications related to near field enhancement materials, optical sensors and surface-enhanced Raman spectroscopy, etc.

pH-sensitive photoluminescence (PL) is an important property of aqueous nanocrystals (NCs) towards NCs-based intelligent applications. Previous works mainly focused on the effect of pH during NC growth process on PL of the aqueous NCs. The effect of pH during application process on PL of as-prepared NCs is still not fully understood. In this work, we brought out a general mechanism for the pH-sensitive PL behaviors of as-prepared aqueous CdTe NCs capped by aqueous thiol ligands, such as carboxylic-acid-terminated 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA) ligands, hydroxyl-terminated 1-thioglycerol (TG) ligands and amine-terminated 2-mercaptoethylamine (MA) ligands. A major contribution of this work is finding the key role of ligand terminal groups in the diffuse process of free Cd-ligand complexes toward NCs. This terminal group effect is the main reason for PL alteration of NCs during pH adjustment process. Besides the terminal group effect, PL of aqueous NCs is also affected by the aggregation effect, the thiol group effect and the counter ion effect. These effects make different contributions to PL of NCs at different pH ranges. By using this mechanism, we successfully explained the complex pH-sensitive PL behaviors of MPA, TGA, TG and MA-capped CdTe NCs.

In this paper, thermal-induced behaviors of a gold nanoparticle monolayer on glass slides are investigated. First, through horizontal lifting, gold nanoparticle monolayers are transferred from a water/hexane interface to glass slides. Then thermal treatment is carried out in air, after which an apparent color change of the obtained samples is noticed, depending on the annealing temperature, reflecting a shift of the surface plasmon band (SPB). Depending on the trend of SPB shift, the overall thermal process is divided into three stages. In the first stage, SPB shows a redshift trend with concomitant band broadening. Further increase of the annealing temperature in the second stage results in an increase of interparticle distance. Thus an apparent decrease in absorbance takes place with SPB shift to shorter wavelengths. In the third stage, the SPB redshifts again. Bulk refractive index sensitivity (RIS) measurements are taken by immersing the obtained samples in solutions of various refractive indices and a linear dependence of RIS(λ) and RIS(ext) on refractive index is concluded. In particular, the influences of parameters such as particle sizes, location of SPB, substrate effect and morphology effect on RIS are discussed in detail. The corresponding performance of each sample as a localized surface plasmon resonance-based sensor is evaluated by a figure of merit (FOM) represented as FOM(λ) and FOM(ext). It is found that the optimum annealing temperature is 500 °C. In terms of nanoparticle sizes, samples with a 35 nm gold nanoparticle monolayer perform better than those with 15 nm. The current strategy is simple and facile to achieve fine control of the SPB, in which large-size precision instruments or complex chemosynthesis are unnecessary. Therefore, this method has not only significance for theory but also usefulness in practical applications.

Incorporation of inorganic nanoparticles (NPs) into polymers is the current means for enhancing the performance of polymer materials, the key to which is the increase of compatibility between NPs and polymer media. In this paper, the polymerizable surfactant octadecyl-p-vinylbenzyldimethylammonium chloride (OVDAC) is synthesized and used as a capping agent for direct synthesis of various metal NPs, for instance Au, Ag, Pd, and Pt, and semiconductor NPs, for instance ZnS, CdS, and PbS. The preformed OVDAC-stabilized NPs are lipophilic and act as macromolecular monomers in the copolymerization with lipophilic monomers.

This paper describes a simple method of sculpturing cavities in silica spheres by reactive ion etching using a polymer as the mask, and investigates the changing process in detail. The morphology of the cavity in the silica structure undergoes transformation in three steps: (1) increase of the diameters of the opening of the cavities; (2) increase of the depth of the cavities; and (3) change in geometry of the resulting structure. As a result, silica bowls or silica rings could be obtained by controlling the etching stage, and this approach can be extended to a wide range, from a micrometer to a nanometer, based on the silica spheres.

Superhydrophobic films with excellent flexibility have been fabricated by combining the lift-up soft-lithography technique and chemical reduction of [Ag(NH(3))(2)](+) ions to Ag nanoparticles (NPs) on the surface of silica spheres which are patterned on the polydimethylsiloxane (PDMS) films. Scanning electron microscopy (SEM) images reveal the presence of raspberry-like hierarchical structures on the PDMS films. The influence of the amount of Ag NPs and the size of the silica spheres on the wettability of the soft films is investigated carefully. Because PDMS films are elastomeric materials, our superhydrophobic films offer great flexibility. The resulting films can be easily transferred from one substrate surface to another without destroying their superhydrophobicity. These flexible and superhydrophobic films can be used repeatedly to satisfy a wide range of applications.

We have developed a method to selectively assemble and align carbon nanotubes (CNTs) on soft substrates for use as flexible biosensors. In this strategy, a thin oxide layer was deposited on soft substrates via low temperature plasma enhanced chemical vapor deposition, and a linker-free assembly process was applied on the oxide surface where the assembly of carbon nanotubes was guided by methyl-terminated molecular patterns on the oxide surface. The electrical characterization of the fabricated CNT devices exhibited a typical p-type gating effect and 1/f noise behavior. The bare oxide regions near CNTs were functionalized with glutamate oxidase to fabricate selective biosensors to detect two forms of glutamate substances existing in different situations: L-glutamic acid, a neurotransmitting material, and monosodium glutamate, a food additive.

Novel one-dimensional (1D) nanostructures of rare earth complexes (europium methacrylate (Eu(MA)(3))) have been prepared from the precursor of irregularly shaped Eu(MA)(3) powder in ethanol solvent without the assistance of an added surfactant, catalyst, or template. These hexagonal-shaped complex nanowires have diameters of about 100-300 nm and lengths ranging from tens to hundreds of micrometers. Nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) studies and thermogravimetric analysis (TGA) show that the precursor powder and the resulting nanowires have identical compositions. Under UV light excitation, strong red fluorescence can be clearly seen throughout the whole wires. This good luminescence characteristic of the complex nanowires is further confirmed by the fluorescence spectrum where strong and narrow emission can be seen. These rare earth complex nanowires provide a useful source for 1D rare earth oxide materials, as the europium ions are distributed uniformly in the Eu(MA)(3) nanowires. Through calcination, the Eu(MA)(3) nanowires are successfully converted into Eu(2)O(3) nanotubes. X-ray investigation confirms that the Eu(2)O(3) nanotubes have a cubic body-centered structure. FTIR measurements and TGA analysis are used to follow the calcination process. A plausible mechanism responsible for the formation of Eu(2)O(3) nanotubes is presented.