Original Article

Electronic and geometric controlling the magnetization orientation of a material in nanoscale is key in developing spintronics, which correlates with tuning its magnetocrystalline anisotropy energy (MCAE). Although the MCAE of a Fe thin film is measured to oscillate with the film thickness and to vary with the amount of injected charges, switching the magnetization orientation electrically is desired. In this work, we provide a microscopic picture based on Fe quantum-well states and spin orbital coupling to explain experimental results (a), and thus predict that the magnetization orientation of a 5-ML Fe film can be switched electrically (b).

We propose and experimentally demonstrate spoof plasmonic metasurfaces with a hyperbolic dispersion, where the spoof SPPs propagate on complementary H-shaped perfectly conducting surfaces at low frequencies. In this way, non-divergent diffractions, negative refraction, and dispersion-dependent spin-momentum locking are observed as the spoof SPPs travel over the hyperbolic spoof plasmonic metasurfaces. They show great capabilities to design advanced surface wave devices such as spatial multiplexers, focusing and imaging devices, planar hyperlenses, and dispersion-dependent directional couplers, at both microwave and terahertz frequencies.

Optically and spatially templated polymer architectures were formed by photopolymerizing reactive mesogens (RMs) in periodically deformed liquid crystals (LCs). Without using lithographic or holographic implements, various polymer patterns could be produced by employing nematic LCs as reaction solvents and spatially nonuniform electric fields with patterned electrodes. The mechanism underlying the observed elastic energy-driven templated phase separation was determined by performing numerical computations of the director field and associated elastic energy. The spatial patterns coincided precisely with the profiles of highly deformed regions, and optical patterns were templated by the local director of the reaction medium. The proposed method provides versatility in forming organized polymer architectures for functional materials requiring both positional and orientational order for their application.

The optical and plasmonic properties of (Bi,Sb)₂(Te,Se)₃ trichalcogenide topological insulator crystals are studied systematically by first-principles density functional theory. These materials exhibit bulk plasmonic properties, dominated by interband transitions, which are better than gold and silver at blue and UV wavelengths. Moreover, topologically protected surface states are also capable of supporting propagating plasmon polariton modes over an extremely broad spectral range, due to a combination of interband and intraband transitions.

A universal dual-electrochromic platform that could operate various advanced logic devices whose outputs visualized by the naked eye was constructed for the first time by introducing the electrochemical oxidation of 2, 2′ -azinobis (3-ethylbenzthiazoline-6-sulfonic acid) and electrodeposition of Prussian blue into one closed bipolar electrode system.

New intrinsic self-healing polymers with outstanding mechanical performance are presented. For this purpose, sterically hindered amines were utilized to crosslink isocyanate containing poly(methacrylates) resulting in urea crosslinked networks. The reversibility of the urea bond during thermal treatment could be utilized to induce self-healing ability and could be proven using various techniques.

The nano-bio interactions of 1D and 2D carbon nanomaterials (COOH-functionalized carbon nanotube (CNT-COOH), graphene nanoplatelet (GNP) and porous graphene oxide (PGO)) with blood plasma proteins (albumin, globulin and fibrinogen) are evaluated in this work. It is demonstrated that these associations may be significantly influenced by the density of the oxygenated functionalities of the nanomaterials and to a certain extent, their dimensionality and surface area. This work offers a broad insight into the carbon nanomaterial–plasma protein interactions and provides a strong basis for the design and use of low-dimensional carbon nanomaterials for a wide variety of biological and biomedical applications.

SEM image of FeCo₂O₄ nanowire arrays on a stainless steel mesh with the schematic of MnO₂//FeCo₂O₄ asymmetric cell and its CV curves.

Here, we present a pressure-modulated heterojunction photodiode composed of n-type multilayer MoS₂ and p-type GaN film by piezo-phototronic effect. Under the illumination of 365 nm incident light, strong photo-response is observed with a response time and recovery time of ~66 and 74 ms, respectively. Upon the pressure of 258 MPa, the photoresponsivity of this photodiode can be enhanced for about 3.5 times by piezo-phototronic effect arising from the GaN film. Due to the lowered junction barrier upon applying an external pressure (strain), more photo-generated carriers can successfully pass through the junction area without recombination, resulting in the enhancement effect.

A new hygromorphic actuator made by hydrophilic metal oxide film was developed, which is moved by the fluid spread on film and the imbibition within a nano-capillary forest. This system possesses a great stability and repeatability for long time and has a very high energy density of ~1250 kJ m^–3. The research results suggest that the actuating nano-capillary forest film could be applicable to humidity-responsive actuators, high-efficiency energy converters and others.

The contact time of droplets impacting on macroscopic anisotropic superhydrophobic surfaces (macro-aniso-SHSs) decreases with an increase in the spacing and the underlying mechanism includes the mass distribution and the momentum anisotropy induced by the parralel macrostripes and macrogrooves. As the figure shows, although the impacting drop on the macro-aniso-SHS with a narrow spacing (400 μm) cannot be divided by the stripes, the anisotropy of the surface concentrates the momentum in the direction parallel to the stripes, leading to breakup and thus reducing the contact time by 15–30% compared with the contact time on the SHS and micro-aniso-SHS. For macro-aniso-SHSs with wide spacing of 1200 μm, the contact time is reduced by 40–50%. The contact time for an impact centered on the stripe is not significantly different from that in the groove, whereas the impact centered in the groove produces new hydrodynamics characterized by extended spreading, easy break-up, and flying-eagle behavior. We envision that understanding the droplet behavior on macro-aniso-SHSs not only extends our fundamental understanding of classical impacting phenomena but also has potential for a broad range of applications, such as anti-icing, self-cleaning and heating transfer.

A single-pass self-assembly approach was developed to demonstrate enhanced antitumor activities from drug-loaded fully lateral nanodimensional graphene oxide flakes under near-infrared irradiation.

Here, we utilize large-size scalable single-crystal 2D films to grow single crystalline inorganic semiconductors. Centimeter-scale hexagonal boron nitride (h-BN) films were synthesized on a single-crystal Ni(111) using chemical vapor deposition (CVD). Single-crystal GaN layers were directly grown on h-BN using metal–organic vapor phase epitaxy. The CVD-grown h-BN exhibited many atomic cliffs that enabled us to grow high-density GaN islands to be merged as homogeneous and flat GaN films. We also investigated the crystallinity and growth mechanism of the GaN films grown on CVD-grown h-BN using transmission electron microscopy and X-ray diffraction.

Organic electronic synapses based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/graphene quantum-dot (GQD) nanocomposites were fabricated by using a solution method. Current–voltage (I–V) curves for the devices under dual positive bias voltage sweeps and under dual negative bias voltage sweeps showed that the conductance with a pinched hysteresis gradually increased and gradually decreased, respectively, with increasing applied voltage which is a fingerprint of e-synapses. The current in the devices was found to decrease with increasing concentration of GQDs in the active layer, and the devices fabricated utilizing the ratio of PEDOT:PSS to GQDs of 1:0.4 showed the best performance among the e-synapses. The carrier transport and operating mechanisms of the e-synapses are described in this paper on the basis of both the I–V results and the trapping and escape of electrons from the GQDs. We believe that our letter contains significant results of interest to a broad spectrum of NPG Asia Materials readers.

We demonstrate the fabrication of three-dimensional, highly ordered protein-based hydrogel platforms for tissue engineering applications. The combination of colloidal templating microfabrication strategies and highly substituted, photocrosslinkable gelatin methacryloyl (GelMA) protein allowed us to fabricate inverted colloidal crystal (ICC) scaffolds with uniform pore interconnectivity, high structural stability and tailorable degradation properties. The resulting scaffolds provided cell attachment sites and promoted intercellular interaction among hepatocytes, which resulted in improved cell function compared to a flat, two-dimensional system. The results demonstrate the potential of GelMA ICC scaffolds to become an effective tissue engineering platform for drug screening and regenerative medicine applications.

We developed a simple but effective protocol to construct uniform FePO₄ coating layer on various substrates. By controlling the precipitation kinetics, we were able to form uniform FePO₄ nanoshells with its thickness precisely defined in nanometer accuracy. Specifically, a core-shell structured electrode material of MWCNTs@FePO₄ was constructed, which showed promising potential as a cathode material for sodium ion battery as revealed by its high discharge capacity as well as the much improved rate capability.

A Homogeneously unidirectional dewetting on large-area microdroplet arrays was developed, which was induced via the gravity-induced deformation in droplets combined with alternating lyophilic/lyophobic patterns. This process allows the scaling-up deposition of thin films including organic semiconductors and transition metal oxides as the autogenous shrinkage of droplets, which further enables the fabrication of large-area organic thin-film transistor (OTFT) arrays. The resulting field-effect mobility and on/off ratio of fully-printed OTFTs exceed 13 cm² V⁻¹ s⁻¹ and 10⁸, respectively.

We report a new anode material that has multifunction of both an anode and a hole injection layer (HIL) as a single layer. Our anode has easy work function tunability up to 5.8 eV and thus makes ohmic contact without any HIL. We applied our anodes to simplified organic light-emitting diodes, resulting in high efficiency (62% ph el⁻¹ for single and 88% ph el⁻¹ for tandem). Our anode showed a similar tendency in simplified perovskite light-emitting diodes. We also demonstrated large-area flexible lightings using our anodes. Our results provide a significant step toward the next generation of high-performance simplified light-emitting diodes.

The bimetallic Au@Rh core–shell nanodendrites with ultrathin Rh nanoplate shells show the light-enhanced catalytic activity for the hydrogen generation reaction from aqueous hydrazine solution.

Micron-thick highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) films are fabricated using a novel self-inhibited polymerization (SIP) approach. The newly adopted inhibitor-free heavy oxidative solutions containing weakly basic anions (WBAs) such as dodecylbenzenesulfonate (DBSA) enables the spin-coating of thick and homogeneous oxidant layer, and meanwhile effectively inhibits both the crystallization of the oxidant and the H⁺ formation throughout the polymerization process.