AbstractFlexible, lightweight, and wearable devices are currently attracting tremendous interest in the field of advanced electronics. In this work, novel 1D, flexible, coaxial-structured, bright and colorful alternating current electroluminescent (ACEL) fibers consisting of AgNW-based electrodes, a ZnS phosphor layer, and silicone dielectric and encapsulation layers are designed and fabricated through a simple protocol. This facile all-solution-based fabrication protocol enables scalable production of long ACEL fibers (>12 cm). Stemming from the rational design and facile fabrication process, the as-prepared ACEL fibers exhibit uniform, bright, and angularly independent luminance (up to 202 cd m−2 @ 195 V and 2 kHz). Benefiting mainly from the robust AgNW-based electrodes and versatile silicone, the ACEL fibers exhibit additionally excellent flexibility and mechanical stability, being capable to maintain ≈91% of luminance after 500 bending-recovery cycles, as well as mitigated luminance degradation after continuous work in ambient. The proper length combined with superb mechanical properties makes the ACEL fibers readily weavable. Most notably, the isolating, hydrophobic, and biocompatible silicone encapsulation layer endows the ACEL fibers unprecedented wearability. Eventually, a proof-of-concept ACEL fabric is demonstrated by weaving the as-prepared long ACEL fibers, to show the future perspective of directly weaving ACEL fibers into densely arrayed wearable functional cloths.

A theoretical study on the thermodynamics of wurtzite (WZ) and zincblende (ZB) ZnO1-xSx was carried out using the first-principles method and the cluster expansion method. The effective cluster interaction of the cluster expansion was calculated, which constructs the formation energy of the disordered alloys. Excluding the contribution of lattice vibrations, the critical temperature of phase separation for the WZ structure is 3946 K and for the ZB structure is 3894 K. Including lattice vibrations, a reduction of the critical temperature by 17.1% was found for the WZ structure, thus increasing the solid solubility of WZ-ZnO1-xSx. In contrast, an increase of the critical temperature by 4.4% was found for the ZB structure when considering lattice vibrations. With analyses of the formation energy and phase diagram, the ZB structure was found thermodynamically more stable than the WZ structure at high temperatures.

•Pt nanoparticles modified dendritic Au nanostructures were obtained via a facile method.•Pt NPs amount on Au can regulate electrocatalytic properties towards methanol oxidation.•PtNPs/DGN showed superior electrocatalytic activity due to synergistic effect of Au and Pt.•PtNPs/DGN exhibited good long-time stability and high poison tolerance for methanol oxidation.A facile and simple method is presented for the synthesis of bimetallic composites, Pt nanoparticles modified dendritic Au nanostructures (PtNPs/DGNs), in which dendritic Au was deposited on a glassy carbon electrode via a potentiostatic method and sphere-like Pt nanoparticles were decorated on Au substrates through a chemical reduction reaction. The compositions, morphologies, and structures of the PtNPs/DGNs were characterized by X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. Results indicated that bimetallic composites were successfully synthesized and spherical Pt nanoparticles were dispersed evenly on dendritic Au substrates. The number of Pt nanoparticles on Au surface was regulated by controlling the chemical reduction deposition time, allowing the electrocatalytic properties of the composite towards methanol oxidation to be tuned. Electrochemical measurements, including cyclic voltammetry and chronoamperometry, were performed to investigate the electrochemical properties and electrocatalytic behaviors of the PtNPs/DGNs towards methanol oxidation. Pt nanoparticles partially covered dendritic Au exhibited dramatically enhanced electrocatalytic activity (3.947 mA cm−2), which was 2.65 times that of commercial carbon-supported Pt nanoparticles (1.487 mA cm−2), along with much improved poisoning tolerance (current decline: 70.85% vs 99.36%). These enhanced performances were likely caused by the large active electrochemical area of the bimetallic nanocomposites and the change in the electronic structure of Pt when the Au surface was modified with fewer Pt nanoparticles.

•[KNbO3]0.9[BaNi1/2Nb1/2O3]0.1 film with high crystalline quality was grown by PLD.•KBNNO thin film has a narrow direct band gap (Eg) of 1.39 eV.•Meanwhile, the thin film exhibits a large room-temperature Pr (1.4 μC/cm2).•Small Eg and large Pr indicate its great potential for developing FPV devices.[KNbO3]0.9[BaNi1/2Nb1/2O3]0.1 (KBNNO) perovskite ferroelectric thin films with narrow band gap (up to 1.39 eV) and good ferroelectric properties are prepared successfully by pulsed laser deposition. The emergence of Ni 3d gap states is confirmed to be responsible for the narrowing down of band gap of KBNNO, which correlates almost linearly with the increase of Ni content. Via a linear fit, a quantitative relationship between the Ni content and the band gap is established, laying a foundation for future design of new KBNNO-based materials with narrow band gap. The room-temperature remnant polarization (up to 1.4 μC/cm2) of the KBNNO thin film is by an order of magnitude higher than that (0.1 μC/cm2) of previously reported thick film with 20 μm thickness. Both narrow band gap and large room-temperature remnant polarization make KBNNO thin films very attractive for developing ferroelectric photovoltaic devices with high conversion efficiencies.(a) Absorption spectra and (b) absorption coefficient times photo energy square (ahv)2 vs. photon energy (hv) plots of KBNNO films deposited at different O2 pressures. (c) The band gap of the films as a function of the Ni content.Download high-res image (155KB)Download full-size image

•Bismuth ferrite/(N-doped) graphene composites were prepared by a hydrothermal method.•Bi25FeO40 and BiFeO3 were obtained with presence of graphene and N-graphene, respectively.•Bi25FeO40/graphene shows superior photocatalytic activity over BiFeO3 and BiFeO3/N-graphene.•A downward band bending (∼0.5 eV) of bismuth ferrite exists at the composites interface.•The downward band bending supposes to be the mechanism for the enhanced photocatalytic activity.Bismuth ferrite/graphene (N-doped graphene) photocatalysts are successfully prepared by a facile and effective two-step hydrothermal method. Bismuth ferrite/graphene shows superior photocatalytic activity compared with bismuth ferrite/N-doped graphene and pure BiFeO3. X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy analyses indicate that Bi25FeO40 crystalline phase is obtained with the addition of graphene, while BiFeO3 is formed under the same hydrothermal conditions in the presence of N-doped graphene. Core-level and valence-band X-ray photoelectron spectroscopy analyses reveal a downward band bending of bismuth ferrite (∼0.5 eV) at the interface of the bismuth ferrite/(N-doped) graphene composites, which facilitates the electron transfer from bismuth ferrite to (N-doped) graphene and suppresses the recombination of photo-generated electron–hole pairs. This downward bending band alignment at the interface supposes to be the main mechanism underlying the enhanced photocatalytic activity of the bismuth ferrite/graphene composites that are currently of great interest in the photocatalysis field.

•PtNCs/graphene (PVP) composites were obtained by a clean and facile method.•The addition of graphene effectively promotes the catalytic performance of composites.•The highly dispersed PtNCs show superior electrocatalytic activity to glucose oxidation.•PtNCs/graphene (PVP) composites exhibit excellent stability and selectivity for nonenzymatic glucose detection.A facile and clean method by using ascorbic acid as mild reductant was developed to synthesize nanocomposites of graphene and platinum nanoclusters (PtNCs/graphene), in which Polyvinyl-Pyrrolidone (PVP) was added during the one-step reductive process so as to improve the dispersity of PtNCs on the graphene and decrease the size of PtNCs. By several characterization methods such as X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), we demonstrated that Pt nanoclusters have successfully anchored on the surface of graphene sheets with average diameter of 22 nm. It was found that with the assistant of PVP, Pt nanoclusters appeared with smaller particle size and narrower particle size distribution. Cyclic voltammetry and amperometric methods were used to evaluate the electro-catalytic activity of the synthesized nanocomposites toward the oxidation of glucose in neutral media (0.1 M PBS, pH 7.4). The PtNCs/graphene exhibited a rapid response time (about 3 s), a broad linear range (1 mM to 25 mM), good stability, and sensitivity estimated to be 1.21 μA cm−2 mM−1 (R = 0.995, 71.9 μA cm−2 mM−1 vs. geometric area). Additionally, the impact from the oxidation of interferences can be effectively limited by choosing the appropriate detection potential. These results indicated a great potential of PtNCs/graphene in fabricating novel non-enzymatic glucose sensors with high performance.

Divalent IIA metals such as Be, Mg, Ca, Sr, Ba and transition IIB metals such as Zn, Cd were investigated as possible n-type dopants into the Cu2O theoretically by using the first-principles calculations based on density functional theory. By systematical analyses of the lattice parameters, the bond length, the electronic structure, the local density of states and the defect formation energy for various doping systems, it is revealed that Ca, Sr, Ba and Be are more suited for n-type doping into Cu2O as shallow donors, compared to Mg which introduces a relatively deep donor level in Cu2O. Meanwhile, Zn and Cd can hardly be doped into Cu2O due to the positive formation energy of relevant defects.

•Pt–Pd nanoparticles/graphene (Pt–PdNPs/G) was synthesized within one-step process.•Environment friendly ascorbic acid was chosen as the reductant.•The synthesized Pt–PdNPs/G exhibits superior electrocatalytic activity and stability towards electro-oxidation of methanol.•The best Pt–Pd ratio of Pt–PdNPs/G for methanol oxidations in alkaline condition belongs to 1/3.A simple, one-step reduction route was employed to synthesize bimetallic Pt–Pd nanoparticles (Pt–PdNPs) supported on graphene (G) sheets, in which the reduction of graphite oxide and metal precursor was carried out simultaneously using ascorbic acid as a soft reductant. The morphology and structure of Pt–PdNPs/G composites were characterized using X-ray diffraction, Transmission Electron Microscopy, Field Emission Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy analysis. The results show that Pt–Pd bimetallic nanoparticles were successfully synthesized and evenly anchored on the graphene sheets. Electrochemical experiments, including cyclic voltammetry and chronoamperometric measurements, were performed to investigate the electrochemical and electrocatalytic properties of the Pt–PdNPs/G composites. It was found that Pt–PdNPs/G composites show better electrocatalytic activity and stability towards the electro-oxidation of methanol than its counterparts such as composites composed of graphene-supported monometallic nanoparticles (PtNPs/G, PdNPs/G) and free-standing (Pt–PdNPs) and Vulcan-supported bimetallic Pt–Pd nanoparticles (Pt–PdNPs/V). The results could be attributed to the synergetic effects of the Pt–Pd nanoparticles and the enhanced electron transfer of graphene. The electrocatalytic activity of Pt–PdNPs/G changed with the Pd content in the Pt–Pd alloy, and the best performance was achieved with a Pt–Pd ratio of 1/3 in an alkaline environment. Our study indicates the potential use of Pt–PdNPs/G as new anode catalyst materials for direct methanol fuel cells.

•Dendrite-like gold nanostructures (DGNs) were obtained by a simple potentiostatic method.•The morphology and structure of DGNs could be easily tuned through the deposition conditions.•The DGNs with high ESA show superior electrocatalytic activity to glucose oxidation.•DGNs exhibit excellent stability and selectivity for nonenzymatic glucose detection.Dendrite-like gold nanostructures (DGNs) were directly electrodeposited onto the surface of a glassy carbon electrode (GCE) via the potentiostatic method without any templates, surfactants, or stabilizers. The effects of the deposition time, potential and the concentration of precursor solution on the evolution of the nanostructure and on the electrocatalytic activity of the DGNs were systematically investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical methods including cyclic voltammetry, linear voltammetry and chronoamperometry. The results confirmed that DGNs have good electrocatalytic activity towards the electro-oxidation of glucose in a neutral phosphate buffer solution (PBS, pH 7.4). A non-enzymatic glucose sensor fabricated with the DGNs as an electrocatalyst showed a quick response (less than 2 s), a low detection limit (0.05 mM), a wide and valuable linear range (0.1 - 25 mM), a high sensitivity (190.7 μA cm−2 mM−1) and good repeatability and stability. In addition, the commonly interfering species, such as ascorbic acid (AA), uric acid (UA), and 4-acetaminophen (AP), did not cause obvious interference because of the use of a low detection potential (0.15 V vs. Ag/AgCl). This work demonstrates a simple and an effective sensing platform for the non-enzymatic detection of glucose.

•Single-phase ZnOS films were grown by PLD in the temperature range of 300–800 °C.•The S concentration in the single-phase ZnOS films can be adjusted from 0.556 to 0.202.•The maximum S content (0.556) is significantly higher than reported solid solubility limits.•The band gap of ZnOS films can be narrowed to 2.63 eV at a low substrate temperature of 300 °C.•The composition and band gap of ZnOS films can be tuned by controlling the substrate temperature.High-quality ZnO1−xSx thin films were grown on (0 0 1) sapphire substrates in the temperature range of 300–800 °C by pulsed laser deposition (PLD) with a ZnS ceramic target and O2 as reactive gas. By increasing the substrate temperature, the crystalline quality of the films is enhanced. The S content in the single-phase ZnO1−xSx films can be systematically adjusted from 0.556 to 0.202 via changing the substrate temperature. The maximum S content in the film grown at 300 °C reaches 0.556 without phase separation, which is significantly higher than the solid solubility limits reported previously for the ZnOS alloys. The narrowed band gap of the ZnO1−xSx film (2.63 eV) grown at the low substrate temperature will extend the application of ZnO-based optoelectronic devices to the blue light region. As the composition, structure, and band gap energy of the ZnOS films were found to depend critically on the growth temperature, this work suggests a simple and flexible means of tuning the composition and optical band gap of ZnOS alloy films by controlling the substrate temperature during the PLD process.

•We grew epitaxial ZnO1-xSx (x ≤ 0.18) films by PLD with a ZnS ceramic target and O2.•Lattice parameters (c, a) and Eg of single-phase ZnO1−xSx  alloys were determined.•C and a expand from 5.204 to 5.366 Å and 3.255 to 3.329 Å with increasing S content.•The optical bandgap shrinks from 3.27 to 2.92 eV with a bowing parameter of 2.91 eV.•In-plane perfectly matched ZnOS/MgZnO heterostructures with max. barrier are proposed.We report on a detailed investigation of the structural and optical properties of single crystalline ZnO1−xSx thin films, placing emphasis on the elucidation of the correlation of the band gap and lattice parameters, particularly the lattice constant a, with the S content in the alloy films. High-quality ZnO1−xSx thin films with different S concentrations Xs (0 ⩽ Xs ⩽ 0.18) were grown epitaxially on c-plane sapphire substrates by pulsed laser deposition using a ZnS ceramic target with varying O2 partial pressures. X-ray diffraction studies revealed that all grown ZnO1−xSx thin films have a single-phase wurtzite structure. With increasing Xs value from 0 to 0.18, both lattice constants c and a expand monotonically from 5.204 to 5.366 Å and from 3.255 to 3.329 Å, respectively, while the optical band gap shrinks from 3.27 to 2.92 eV with a bowing parameter of 2.91 eV. Based on these information, ZnOS/MgZnO heterostructures that have a perfect in-plane lattice match and a maximum barrier height can be proposed, which might eventually lead to new optoelectronic devices with superior performance.

•Hexagonal nanoplates of Wurtzite CuInS2 were synthesized by a hot-injection method.•A novel cost-effective solvent of monoethanolamine was employed in the reaction.•The reaction took place under mild conditions that are beneficial for scalability.Wurtzite copper indium disulfide (CuInS2) nanoplates were synthesized via a low-cost, facile solution-based method. The reaction was carried out at 140 °C for an hour under nitrogen atmosphere by using the solvent of monoethanolamine (MEA). The experimental results revealed that the products had good crystallinity, monomorphology and stoichiometric composition. The solvent material, reaction time and temperature played important roles in the formation of the wurtzite CuInS2 nanoplates. The possible growth mechanism was also proposed and discussed. And the wide stoichiometry of the wurtzite-CuInS2 implies that this work may offer a new strategic approach for the synthesis of I–III–VI2 ternary semiconductor nanocrystals as new solar energy materials.

[(Na0.5+yK0.5−y)0.94Li0.06][(Nb0.94Sb0.06)1−xTax]O3 + 0.08 mol% MnO2 lead-free piezoelectric ceramics were fabricated successfully by a conventional solid-state reaction method. The effects of Ta5+ substitution and K/Na ratio variation on the microstructure and properties of the ceramics have been systematically investigated. With the increasing of Ta5+ substitution content, the orthorhombic–tetragonal transition temperature To–t presents obvious “V” type variation while the Curie temperature Tc decreases monotonically. The ceramics properties were further enhanced by adjusting the Na/K ratio of the A-site. Under systematical optimization of the A-site and B-site elements, good overall electrical properties of d33 = 276 pC/N, kp = 44.5%, ε33T/ε0 = 1,175, tanδ = 0.027, Tc = 309 °C, Pr = 21.0 μC/cm2, and Ec = 1.14 kV/mm were obtained for ceramics with Ta5+ content x of 0.05 and Na/K ratio of 57/43 (y = 0.07).

•Pd nanoparticles/graphene (PdNPs/graphene) was synthesized within one-step process.•Environment friendly ascorbic acid was chosen as the reductant.•The synthesized PdNPs/graphene shows superior electrocatalytic activity to both methanol and ethanol.•PdNPs/graphene shows superior electrocatalytic stability in methanol and ethanol electro-oxidation.Well-dispersed Pd nanoparticles (PdNPs) supported on graphene sheets were successfully prepared by a simple one-pot process, in which the reduction of Poly Vingl Pyrrolidone-functionalized graphite oxide and Pd precursor was carried out simultaneously using ascorbic acid as a soft reductant. The Pd nanoparticles decorated graphene composite (PdNPs/PVP-graphene) was characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Morphology and structure characterizations directly showed that Pd nanoparticles with crystallite size of about 8.5 nm were evenly formed on graphene. Catalysis activity as in fuel cells was investigated by further electrochemical experiments including cyclic voltammograms and chronoamperometric measurements. Compared to the commercial Vulcan XC-72 supported Pd nanoparticles, PdNPs/PVP-graphene exhibits superior electrocatalytic activity and stability toward electro-oxidation of alcohols, showing its potential use as new electrode material for direct alcohol fuel cells (DAFCs).

The graphene supported platinum nanoclusters was synthesized by an efficient and clean method, in which graphene oxide and Pt ion precursor were reduced by ascorbic acid within one-step process. The obtained Pt nanoclusters attached graphene composite (PtNCs/graphene) was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS), which can directly show that Pt nanoclusters successfully formed on graphene and well distributed on the edges and wrinkles of graphene sheets. The further electrochemical characterizations including cyclic voltammograms (CV), current–time methods indicated that PtNCs/graphene has significantly higher electrocatalytic activity and stability for methanol electrooxidation compared to the normal Vulcan XC-72 and graphite supported Pt nanoclusters, which will lead a further application as a new electrode material in direct methanol fuel cell (DMFC).Highlights► Pt nanoclusters/graphene (PtNCs/graphene) was synthesized within one-step process. ► Environment friendly ascorbic acid was chosen as the reductant. ► The synthesized PtNCs/graphene show superior electrocatalytic activity to methanol. ► PtNCs/graphene show superior electrocatalytic stability in methanol electrooxidation.

High-quality ZnO1−xSx thin films were grown epitaxially on c-plane sapphire substrates by pulsed laser deposition using a ZnS ceramic target with varying O2 partial pressures. Single-phase ZnO1−xSx alloys with a wurtzite structure were achieved in composition ranges of 0 ⩽ x ⩽ 0.23 and 0.94 ⩽ x ⩽ 1. Phase separation, i.e., coexistence of ZnO and ZnS in ZnOS ternary alloys was observed for compositions of 0.23 < x < 0.94. The extended S solubility (up to 0.23) implies that ablating the ZnS target under oxygen atmosphere is an efficient way to incorporate S into ZnO towards ZnOS alloys formation. The work provides additional information on the O solubility (0.06) in the S-rich ZnOS films grown by pulsed laser deposition. These results are of importance when considering ZnO1−xSx for making ZnO based quantum structures for advanced optoelectronic devices.Highlights► High-quality epitaxial ZnOS films were grown by PLD using a ZnS ceramic target and O2 as reactive gas. ► Single-phase ZnO1−xSx (0 ⩽ x ⩽ 0.23 and 0.94 ⩽ x ⩽ 1) alloys with a wurtzite structure were achieved. ► Phase separation was observed in ZnO1−xSx films of 0.23 < x < 0.94. ► The S solubility is extended to 0.23 while the O solubility of 0.06 is additionally given. ► Ablating the ZnS while oxidizing is an efficient way towards ZnOS alloys formation.