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The 2D/1D mixed‐dimensional van der Waals heterostructures have great potential for electronics and optoelectronics with high performance and multifunctionality. The epitaxy of 1D micro/nanowires on 2D layered materials may efficiently realize the large‐scale preparation of 2D/1D heterostructures, which is critically important for their practical applications. So far, however, only the wires of Bi2S3, Te, and Sb2Se3 have been epitaxially grown on MoS2 or WS2. Here, it is reported that the epitaxial growth of 1D CsPbBr3 nanowires on 2D Bi2O2Se nanoplates through a facile vertical vapor deposition method. The CsPbBr3 wires are well aligned on the Bi2O2Se plates in fourfold symmetry with the epitaxial relationships of [001]CsPbBr3||[200]Bi2O2Se and [1‐10]CsPbBr3||[020]Bi2O2Se. The photoluminescence results reveal that the emission from CsPbBr3 is significantly quenched in the heterostructure, which implies the charge carriers transfer from CsPbBr3 to Bi2O2Se. The waveguide characterization shows that the epitaxial CsPbBr3 wires may efficiently confine and guide their emission, which favors the light absorption of Bi2O2Se. Importantly, the photocurrent mapping and spectra of the devices based on these 2D/1D heterostructures prove that the epitaxial CsPbBr3 wires remarkably enhances the photoresponse of Bi2O2Se, which indicates these heterostructures can be applied in high‐performance optoelectronic devices or on‐chip integrated photonic circuits.

Microbial infections continue to pose a serious threat to human health, thus calling attention to the development of new materials with better antibacterial applications. Here we report a microfluidic approach to fabricate core–shell GO-AgNPs/BC (graphene oxide–silver nanoparticles/bacterial cellulose) hydrogel microfibers with controlled-releasing and long-lasting antibacterial performance. Meters of the composite microfibers can be produced in 1 min by using a homemade microfluidic wet-spinning device. The as-prepared microfibers exhibit well-controlled morphological features at the nanoscale and excellent mechanical properties. We have demonstrated that the composite microfibers can effectively sterilize both Gram positive and negative bacterial strains, while remaining friendly to normal mammalian cells. This flexible approach of synthesizing core–shell composite microfibers promises important biomedical applications including materials science, tissue engineering, and regenerative medicine.

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A simple and environmentally-friendly bio-oxidation approach to produce graphite oxide nanosheets is described.

1D all-inorganic perovskites microwires horizontally aligned on mica show great potential in high performance optical and optoelectronic devices. In spite of the tremendous progress in their growth and properties studies, the growth mechanism for epitaxy of perovskites microwires on mica has not been well understood. Herein, we present a home-built in situ growth monitoring system to study the growth mechanism of the CsPbBr3 microwires on mica with the physical vapor deposition (PVD). Through in situ monitoring the growth of the CsPbBr3 microwires, the detailed growth behavior can be directly investigated. It is found that the length growth rate of the microwires may be enhanced with the large undercooling (the temperature difference between the precursor and the deposition substrate), which provides the possibility to achieve the rapid growth of the wires. Additionally, CsPbBr3 microwires with smaller diameter show the higher growth rate than that with larger diameter, which is consistent with the theoretical analysis based on the adatom diffusion. By increasing the undercooling, CsPbBr3 microwires with the length up to 200 μm can be grown in 15 s, which is more efficient than the traditional vapor growth routes. Furthermore, the photoluminescence and high performance of the photodetector device based on these CsPbBr3 wire arrays indicate that the as-grown CsPbBr3 wires have the potential in the optical and optoelectronic device applications.

Semiconductor nanowires (NWs) are considered the ideal building blocks for future nanodevices. [1] In particular, because of their 1D geometry, NWs have attracted tremendous attention due to their potential applications in waveguides, [2] nanolasers, [3] photodetectors (PDs), [4] and field-effect transistors. [5] Although great progress has been made in the synthesis of semiconductor NWs, most of the reported wires were grown with random orientations, which restrained their application in high-density integrated circuits. [6] Generally, practical utilization at the circuit level requires the large-area horizontal alignment of semiconductor NWs with a controlled orientation on a substrate. Several techniques, such as optical tweezers, [7] micromanipulation, [8] and Langmuir-Blodgett assembly [9] may align NWs in well-organized arrays. However, these postgrowth assembly strategies are still subject to poor controllability, low throughput, and high cost, which prevents their application in scale production. [3a,10] The direct epitaxy of semiconductor NWs on an appropriate substrate has great potential to efficiently produce macroscopic-scale wire arrays with horizontal alignment through combining the growth and assembly of NWs into one step. The guided growth of laterally aligned NWs has been successfully achieved for InP NWs on germanium, [11] GaAs NWs on GaAs (100) substrates, [12] GaN and ZnSe NWs on sapphire, [10a,13] etc. These covalent hetero-or homoepitaxies strictly require the substrates and the corresponding epitaxial NWs to have similar crystalline symmetries, lattice parameters, and thermal expansion coefficients to avoid large interface strain. Moreover, the chemical covalent bonds formed between epitaxial NWs and substrates make wire arrays difficult to be peeled off from the grown substrates. This prevents the wires from further being transferred onto other substrates for various functional device applications. Mica, a typical layer-structured mineral, can act as an ideal deposition substrate interacting with the epitaxial wires by the van der Waals (vdW) force, due to its danglingbond-free and atomically smooth surface. [14] The weak vdW force dominated incommensurate epitaxy of wires horizontally on vdW substrates may tolerate a large lattice mismatch, while the wires may still maintain a definite in-plane direction relative to the substrate to minimize the system energy. [15] In addition, the weak interacting force between the epitaxial wire and mica facilitates the transfer of the grown wire arrays without any corrosive reagents etching the substrate, but with the assistance of water. [16] Although mica has been extensively used as a vdW epitaxial substrate for the growth of vertically aligned semiconductor wires and 2D materials, [16,17] the growth of horizontally aligned semiconductor wires on mica is only limited to the material systems of WO 3 , Pb 1Àx Sn x Se, and all inorganic perovskites. [18]