Original Article in 2016

A minute presence of silver nanoclusters in a MoS₂ nanosheet–graphene composite was found to significantly increase the reversibility of Li⁺ storage in the composite through Li⁺ association, pillaring of graphene and the immobilization of S species.

A new surface-directed crystallization mechanism enabled by the chemical and structural inhomogeneity of the glass substrate through self-limited nanocrystallization of glassy phase was proposed and demonstrated. Benefiting from the intricate interplays between nanoscale force and heterogeneous surface, the strategy offers new opportunities in the large-scale development of various metastable crystallization products and also serves practical purpose.

To realize practical application, the attenuation of spin waves because of boundary scattering and multimode dispersion in magnonic waveguides must be greatly reduced. Up to now, there have been not good solutions to this problem. Here, we propose and demonstrate by micromagnetic simulations to use the longitudinal chiral domain wall imprinted into a waveguide with the interfacial Dzyaloshinskii–Moriya interaction (DMI) to introduce a deep potential well and guide spin waves forming an ultra narrow internal spin-wave channel (~10 nm). Spin waves along this channel can prevent scattering arising from boundary roughness and multimode coexistence and thus should exhibit reduced attenuation and enhanced coherence, which is highly desired in building real spin-wave devices. Moreover, we show that the spin-wave transmission in this waveguide with the DMI can be switched on and off at the frequencies lower than a threshold frequency f₂ by changing the static domain state. This property is explored to construct logical NAND gate by connecting two logical NOT gates in parallel.

Trimodally porous SnO₂ nanospheres with pore sizes of 3, 20 and 100 nm were prepared with facile one-pot spray pyrolysis and their potential for extremely sensitive ethanol detector was demonstrated. The precise control over, as well as the tuning of, multimodal pores in metal oxide nanostructures provides a new and general strategy for enhancing the performance of nanomaterials for various energy and environmental applications.

Two parallel semiconducting TiO₂ zones, anatase and rutile, are made to have lower and higher electron densities, respectively, and form periodically organized junctions through anatase–rutile-phase transition in selective areas by laser irradiation on the titanium bone implants. The periodic junctions result in the formation of a periodic microscale electric field (MEF), built-in on the implants, which in turn efficiently induces and promotes osteogenesis.

The polarization-electric-field hysteresis curves of the polar c-axis-grown orthorhombic GaFeO₃ (o-GFO) film on a SrRuO₃/STO substrate show the net switching polarization of ~35 μC cm⁻² with an unusually high coercive field (E_c) of ±1400 kV cm⁻¹ at room temperature. The positive-up and negative-down measurement also demonstrates the switching polarization of ~26 μC cm⁻². The activation energy for the polarization switching, as obtained by density-functional theory calculations, is remarkably high, 1.05 eV per formula unit. We have theoretically shown that this high value accounts for the extraordinary high E_c and the stability of the polar Pna2₁ phase over a wide range of temperature up to 1368 K.

Herein, we elaborated a facile and generally applicable synthetic strategy to ensure confinement of uniformly dispersed noble-metal nanoparticles (Au, Pt, Rh, Ru, Ag, Pd and Ir) within various carbon morphologies with controlled loadings from 8 to 44%. The metal nanoparticles were small (~2 nm), but importantly were evenly distributed throughout the carbon support even at the highest loading, allowing for a significantly higher surface area for rapid and even selective catalysis.

When brushes are removed from an ink bath, they sometimes show unwanted droplets, which may accidentally drop on surfaces. Our theory predicts that Chinese calligraphic brushes eliminate the unwanted droplets by closing their ends. The ends of the brushes are closed when the length L of their fibers is longer than a critical length L_clo. This principle may be applicable to the design of liquid-transfer devices.

The graphene aerogel (GA) cathode has unique properties with a hierarchically porous structure that facilitates electrolyte permeation and oxygen diffusion, three-dimensional network structures that can enable easy electron transfer through GA, high specific surface area that offers abundant active sites for electrochemical reaction and an ultra-large pore volume that can accommodate plenty of discharge products. Ru nanoparticles supported on graphene sheets also has superior catalytic activity toward oxygen evolution reaction and can efficiently catalyze the decomposition of the discharge product Li₂O₂.

Amide group-containing polymer functionalized on carbon surfaces selectively interacts with the Co precursor, resulting in Co–N bond formation on PtCo nanoparticle surfaces. The electron transfer from Co to Pt is enhanced due to increased electronegativity difference between Pt and Co. In addition, the dissolution of Co and Pt during the oxygen reduction reaction (ORR) is retarded by the selective passivation of surface Co atoms and the decrease in the O-binding energy of surface Pt atoms. As a result, the catalytic activity and durability of the hybrid PtCo nanoparticles for the ORR are significantly improved by the electronic ensemble effects.

We report microscale magnetically actuated, cell-laden hydrogels (μMACs) for investigating the strain-induced cell response in three-dimensional (3D) microenvironments. These μMACs provide high-throughput arrays of defined 3D cellular microenvironments that undergo reversible, relatively homogeneous deformation following non-contact actuation under external magnetic fields. Such technique not only enables the application of high strains (up to 60%) to cells but also enables simplified microscopic visualization of these specimens under tension. The μMACs offer insights for mechanotransduction and may also provide a view of how cells respond to extracellular matrix in 3D.

Low-voltage (<5 V) organic memory transistors with outstanding retention stability (>10 000 cycles), which were achieved by employing both the P3HT channel layer and the PVA gate-insulating memory layer, were strongly influenced by the PVA molecular weights due to the different orientation of hydroxyl dipoles.

In this study, we coordinated the ionic current and the fluorescence signal to reveal that the gatekeepers (here, oligomers) open and close the nanochannels with an ‘onion-like’ intermediate state, as confirmed by molecular dynamics simulations. The dual-signal-output nanochannels exhibited a high sensitivity and selectivity to glucose and showed a high antijamming property. Ten healthy individuals’ urine samples were distinguished from those of 15 diabetes patients; moreover, the urine samples of the diabetes patients could be discriminated before and after treatment with insulin.

We propose hybrid approach of two classes of PbS QD as NIR light absorber and IGZO as the photogenerated charges acceptor/transport semiconductor to create phototransistor for near infrared (NIR) detection/imaging. Such hybrid phototransistor shows photodetection capability between 700 and 1400 nm. We demonstrate a NIR (1300 nm) imager using photogating inverter pixel based on PbS/IGZO hybrid phototransistor.