Original Article in 2014

Au/Ni₁₂P₅ core/shell nanocrystals with single crystalline shells are synthesized via an in situ phosphorization of dumbbell-like Au–Ni nanoparticles (NPs) as precursors. The obtained core/shell Au/Ni₁₂P₅ NPs are served as supercapacitor electrode materials with distinct enhanced super-capacitance characteristics compared with pure Ni₁₂P₅ and oligomer-like Au–Ni₁₂P₅ NPs. This synthesis method provides a new strategy to fabricate metal–semiconductor nanomaterials for enhanced properties.

Antimicrobial-containing nanocomposite coatings can respond to bacterial challenge through multiple mechanisms and show unprecedented antibacterial efficacy. Coatings composed of similarly charged montmorillonite (MMT) clay nanoplatelets and polyacrylic acid (PAA) can take up and sequester large amounts of antibiotics under normal physiologic conditions, preventing the development of antibiotic resistance. When challenged with media-acidifying bacteria (Staphylococcus aureus, Staphylococcus epidermidis or Escherichia coli), they release PAA-bound gentamicin and increase their water uptake, while retaining MMT-bound antibiotics. These multiple bacteria-triggered responses, together with biocompatibility to tissue cells, make these coatings promising candidates for protecting biomaterial implants and devices against bacterial colonization.

Spinel Li₄Ti₅O₁₂ nanoparticle has been demonstrated as an Mg-ion insertion anode material with ‘zero-strain’ characteristics (only ∼0.8% volume change) during Mg-ion insertion/extraction cycles, and a remarkable capacity retention capability of >95% after 500 cycles.

Large-area and high-crystalline photoreduced graphene oxide films are fabricated by the combination of solution-processable strategy and subsequently room temperature photoreduction directly on flexible conductive substrates.

A novel two-step approach is presented for the fabrication of self-assembled monolayers of platinum nanocrystals (SAM-Pt) uniformly deposited on a transparent conducting oxide (TCO) surface to serve as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). A true self-assembled Pt nanocrystalline monolayer with a mean particle size of ∼3 nm at facet {111} was unambiguously observed in the high-resolution TEM images. We emphasize that the SAM-Pt films feature a clean surface, uniform morphology, narrow size distribution, small Pt loading and great catalytic activity; the present approach is hence not only suitable for DSSCs but is also promising for many other energy-related applications that require platinum as an efficient catalyst to expedite the oxygen reduction reaction (ORR).

Unconventional nanoporous antenna-like heterostructure arrays, inspired by insect tentacles, are developed for efficient interfacial sensing of biomolecules and cellular activities. The obtained nanoporous cubes (head segments) serve as a robust substrate for site-selective cell adhesion and culture, allowing for sensitive detection of biomolecules. Meanwhile, the single-crystalline nanowires (arm segment) provide efficient charge transport toward the electrode substrate. The inspired hetero-biointerfaces exhibit substantial enhanced electrocatalytic activity and sensitivity for biomolecules.

3D-networked boron-doped diamond/carbon nanotube (BDD–CNT) core-shell nanowires were fabricated using the electrostatic self-assembly of nanodiamond. Although CNTs are easily etched out at their defect sites in hydrogen-rich environments, densely attached nanodiamond particles suppressed the etching of the CNTs and promoted BDD growth. After BDD deposition, 3D-networked BDD–CNT nanowires were successfully developed. In comparison to other electrodes, the BDD–CNT electrode exhibited better electrochemical performances, that is, low electron transfer resistance, large effective surface area and high sensitivity with significantly low detection range (8.7 mA mM⁻¹ in the range 0.65–83.75 nM). The improvement in the performances of the BDD–CNT electrode could be attributed to the geometry and electron pathways offered by CNTs as well as to the synergistic material properties of BDD and CNT. The BDD–CNT electrode shows promise for application in the noninvasive measurement of glucose in living beings as well as for environmental monitoring in sea water.

ATP can act an ideal boosting agent for markedly improving the peroxidase-like catalytic activity over a broad temperature range.

By fabricating a pH-responsive smart device with tunable surface-wetting properties, we have realized continuous in situ separations of oil/water/oil ternary mixtures without ex situ treatments of cleaning or drying. In air, the superhydrophobic/superoleophilic surface of the smart device allowed heavy oil to permeate through while preventing water from passing. When exposed to alkaline water, the superhydrophilicity/underwater superoleophobicity of the smart device surface prevented the passage of hexane while allowing water to penetrate. In this way, efficient separation and collection of the individual components of a complex oil/water/oil mixture was realized in a continuous process with no ex situ treatments. This method could provide a strategy for continuous separations of oil/water/oil ternary mixtures, which are common in practical oil spill cases.

Four oligonucleotide strands are hybridized to form the 3D DNA nano-pyramid. Three thiol groups-terminated vertex can immobilize the pyramid firmly onto the surface of gold electrode, while the remaining non-thiolated vertex at the top with carboxyl group allows the covalent binding of anti-IgG antibody. Through traditional sandwich immunoreaction, the electroactive tag, ferrocene (FeC) generates electrochemical signals used to detect the analyte IgG. The pyramidal structure with higher rigidity encourages more uniform surface assembly and less steric effect, resulting in lower background interference. The pyramid's hollow structure further contributes to efficient electron transfer and makes this immunoassay system achieve an ultrasensitive detection limit.

We report here on the effects of grains of PbS with different length scales on thermal conductivity reduction and bipolar effect ‘suppression’ through macro-properties/microstructure analysis. We found that nanograins can achieve the above goals simultaneously. Combining experimental results and theoretical calculations, we found that the effect of nanograins on the reduction in lattice thermal conductivity can surpass that of nanoprecipitates. Improved properties corresponding to the lowest lattice thermal conductivity in a PbQ (Q=Te, Se, S) system (0.5 W m K⁻¹ at 923 K) and the highest ZT value in PbQ nanocrystalline materials were achieved by the nanograin method.

A highly thermal and oxidation-resistive AZO/Cu nanowire/AZO composite electrode for thin-film solar cells was fabricated at room temperature without any atmospheric control. Our novel transparent composite electrode showed good thermal oxidation stability as well as high conductivity (∼35.9 Ω/sq), transparency (83.9% at 550 nm) and flexibility.

We report a novel design of graphene as electrical sensor for single-molecule detection, by employing natural self-assembly properties of graphene/multilayered h-BN/graphene for single-molecule detection. The novelty of our design is that we use the top and bottom graphene layers as two separate electrodes while the sandwiched h-BN layers as the insulating dielectric. Our theoretical study indicates that the ordered stacking of h-BN dielectric in the nanopore will result in intriguing quantum interference effects, which can be utilized for enhancing the sensitivity of the proposed device.

For n–p-junctioned QD-P3000 hybrid NPs, the PL intensity from the green QD drastically decreased and that of the π-conjugated P3000 was weakly changed due to energy and charge transfer effects. The photocurrent of the QD-P3000 was much higher and more symmetric than that of the QD-CB NP, which had an insulating molecular block, suggesting more active charge transfer between the p-type P3000 and the n-type QD. The nanoscale PL and molecular optoelectronic properties of the hybrids of QDs and π-conjugated molecules could be tuned by their relative distance and the degree of spectral overlapping.

Nanoscale functionalized graphenes are fabricated by atomic force microscopy lithography with the desired coverage of a selective functional group using the simple method of the electrical control, and their recovery through moderate thermal treatments. Surprisingly, our controlled coverage of functional groups can reach 94.9% for oxygen and 49.0% for hydrogen, well beyond the coverage achieved by conventional methods.

We report the world’s first superconducting joint for second-generation GdBa₂Cu₃O_7-δ-coated conductors (2G GdBCO CCs) based on atomic diffusion in GdBCO with partial melting and oxygen diffusion into the oxygen-deficient GdBCO lattices. Producing the superconducting joint requires multiple processes, including fabrication of microholes, peeling off stabilizers, heat treatment and oxygenation annealing. The I_c value of the joined and parent CCs at 77 K are identical, and the initially induced magnetic field of a model coil containing the joint is maintained without decreasing. This method is a unique solution for achieving persistent current mode operation in 2G high-temperature superconducting magnet applications.

Powerful micro-/nano-motors with high speeds and large driving forces in fluids are of great importance in propelling micro-/nanomachines for various tasks. Here, we achieved highly efficient catalytic locomotion in microtubular engines with hierarchical nanoporous walls. The sophisticated structures provide an enlarged surface area and better reactant accessibility, which remarkably enhances their catalytic activity toward H₂O₂ decomposition, accelerating the microengine’s speed. The fast catalytic locomotion of such hierarchical nanoporous microtubes makes them excellent candidates as efficient micro-machines for biomedical applications.

Highly transparent and strongly adhesive conductive networks embedded in the surface of cellulose nanofiber paper are prepared by a simple filtration coating process. As-prepared transparent conductive paper shows sheet resistance of 12 Ω sq.⁻¹ with specular transmittance of 88%, which is up to 75 times lower than the sheet resistance on a polyethylene terephthalate film prepared by conventional coating processes. In addition, the transparent conductive paper is folded with negligible changes in electrical conductivity, opening new doors for future paper electronics.

We have analyzed the effect of the morphology of the pentacene films confined in the micro- and nano-scale relief patterns on the charge transport. As the patterned space region for confining the growth of organic semiconductors decreased to below the average grain size (∼ 1.7 μm), the field-effect mobility increased. Because the molecular ordering is influenced by the pattern’s confining effect on pentacene film growth. Our results will provide an approach that can be used to further increase the charge transport mobility of polycrystalline organic semiconductors by increasing the molecular ordering in the direction of charge transport.

Solid-state films made from deoxyribonucleic acid where the mechanical properties are controllable, from glassy to rubbery, via semicrystalline by simply regulating the water content in the film.