The recharge ability of zinc metal‐based aqueous batteries is greatly limited by the zinc anode. The poor cycling durability of Zn anodes is attributed to the dendrite growth, shape change and passivation, but this issue has been ignored by using an excessive amount of Zn in the past. Herein, a 3D nanoporous (3D NP) Zn–Cu alloy is fabricated by a sample electrochemical‐assisted annealing thermal method combined, which can be used directly as self‐supported electrodes applied for renewable zinc‐ion devices. The 3D NP architectures electrode offers high electron and ion transport paths and increased material loading per unit substrate area, which can uniformly deposit/strip Zn and improve charge storage ability. Benefiting from the intrinsic materials and architectures features, the 3D NP Zn–Cu alloy anode exhibits high areal capacity and excellent cycling stability. Further, the fabricated high‐voltage double electrolyte aqueous Zn–Br2 battery can deliver maximum areal specific capacity of ≈1.56 mAh cm−2, which is close to the level of typical commercial Li‐ion batteries. The excellent performance makes it an ideal candidate for next‐generation aqueous zinc‐ion batteries.

We adapt the Halperin–Mazenko formalism to analyze two-dimensional active nematics coupled to a generic fluid flow. The governing hydrodynamic equations lead to evolution laws for nematic topological defects and their corresponding density fields. We find that ±1/2 defects are propelled by the local fluid flow and by the nematic orientation coupled with the flow shear rate. In the overdamped and compressible limit, we recover the previously obtained active self-propulsion of the +1/2 defects. Non-local hydrodynamic effects are primarily significant for incompressible flows, for which it is not possible to eliminate the fluid velocity in favor of the local defect polarization alone. For the case of two defects with opposite charge, the non-local hydrodynamic interaction is mediated by non-reciprocal pressure-gradient forces. Finally, we derive continuum equations for a defect gas coupled to an arbitrary (compressible or incompressible) fluid flow.

In this paper, thermal treatment of Zn(NH 3 ) 4 2+ precursor in ethanol solvent leading to the formation of the ZnO hollow spheres is reported. It was demonstrated that the pH value of the initial mixture and the volume ratio of the ethanol with the solution plays the key function in the formation of hollow spheres. Transmission electron microscopy and scanning electron microscopy images showed that hollow spheres of ∼600 nm in diameter were built by ZnO nanorods. On the basis of experimental results, a possible formation mechanism in the growth processes is discussed.

Herein, we report for the first time a colorful chromogenic substrate, which displays vivid color responses in the presence of different concentration of analytes. Our investigation reveals that the selective shortening of gold nanorods (AuNRs) could generate a series of distinct colors that covers nearly the whole visible range from 400 to 760 nm. These vivid colors can be easily distinguished by the naked eye; as a result, the accuracy of visual inspection could be greatly improved. Next, we demonstrate the utility of AuNRs as multicolor chromogenic substrate to develop a number of colorimetric immunoassay methods, e.g., multicolor enzyme-linked immunosorbent assay (ELISA), multicolor competitive ELISA, and multicolor magnetic immunoassay (MIA). These methods allow us to visually quantify the concentration of a broad range of target molecules with the naked eye, and the obtained results are highly consistent with those state-of-the-art techniques that are tested by the sophisticated apparatus. These multicolor portable and cost-effective immunoassay approaches could be potentially useful for a number of applications, for example, in-home personal healthcare, on-site environmental monitoring, and food inspection in the field.

Interfacial engineering and heterostructures designing are two efficient routes to improve photoelectric characteristics of a photodetector. Herein, a Ti3C2 MXene/Si heterojunction photodetector with ultrahigh specific detectivity (2.03 × 1013 Jones) and remarkable responsivity (402 mA W−1) at zero external bias without decline as with increasing the light power is reported. This is achieved by chemically regrown interfacial SiOx layer and the control of Ti3C2 MXene thickness to suppress the dark noise current and improve the photoresponse. The photodetector demonstrates a high light on/off ratio of over 106, an outstanding peak external quantum efficiency (EQE) of 60.3%, while it maintains an ultralow dark current at 0 V bias. Moreover, the device holds high performance with EQE of over 55% even after encapsulated with silicone, trying to resolve the air stability issue of Ti3C2 MXene. Such a photodetector with high detectivity, high responsivity, and self‐powered capability is particularly applicable to detect weak light signal, which presents high potential for imaging, communication and sensing applications.

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It is widely believed that the lack of high-quality GaN wafers severely hinders the progress in GaN-based devices, especially for defect-sensitive devices. Here, low-cost AlN buffer layers were sputtered on cone-shaped patterned sapphire substrates (PSSs) to obtain high-quality GaN epilayers. Without any mask or regrowth, facet-controlled epitaxial lateral overgrowth was realized by metal-organic chemical vapor deposition. The uniform coating of the sputtered AlN buffer layer and the optimized multiple modulation guaranteed high growth selectivity and uniformity of the GaN epilayer. As a result, an extremely smooth surface was achieved with an average roughness of 0.17 nm over 3 × 3 μm. It was found that the sputtered AlN buffer layer could significantly suppress dislocations on the cones. Moreover, the optimized three-dimensional growth process could effectively promote dislocation bending. Therefore, the threading dislocation density (TDD) of the GaN epilayer was reduced to 4.6 × 10 cm, which is about an order of magnitude lower than the case of two-step GaN on the PSS. In addition, contamination and crack in the light-emitting diode fabricated on the obtained GaN were also effectively suppressed by using the sputtered AlN buffer layer. All of these advantages led to a high output power of 116 mW at 500 mA with an emission wavelength of 375 nm. This simple, yet effective growth technique is believed to have great application prospects in high-performance TDD-sensitive optoelectronic and electronic devices.

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