The Electrochemical Response of Single Crystalline Copper Nanowires to Atmospheric Air and Aqueous Solution.

In this paper, single crystalline copper nanowires (CuNWs) have been electrochemically grown through anodic aluminum oxide template. The environmental stability of the as-obtained CuNWs in both 40% relative humidity (RH) atmosphere and 0.1 m NaOH aqueous solution has been subsequently studied. In 40% RH atmosphere, a uniform compact Cu2 O layer is formed as a function of exposure time following the logarithmic law and epitaxially covers the CuNW surfaces. It is also found that the oxide layers on CuNWs are sequentially grown when subjected to the cyclic voltammetry measurement in 0.1 m NaOH solution. An epitaxially homogeneous Cu2 O layer is initially formed over the surface of the CuNW substrates by solid-state reaction (SSR). Subsequently, the conversion of Cu2 O into epitaxial CuO based on the SSR takes place with the increase of applied potential. This CuO layer is partially dissolved in the solution forming Cu(OH)2 , which then redeposited on the CuNW surfaces (i.e., dissolution-redeposition (DR) process) giving rise to a mixed polycrystalline CuO/Cu(OH)2 layer. The further increase of applied potential allows the complete oxidation of Cu2 O into CuO to form a dual-layer structure (i.e., CuO inner layer and Cu(OH)2 outer layer) with random orientations through an enhanced DR process.

Ordered arrays of Au-nanobowls loaded with Ag-nanoparticles as effective SERS substrates for rapid detection of PCBs.

Large-scale hexagonally close-packed arrays of Au-nanobowls (Au-NBs) with tens of Ag-nanoparticles (Ag-NPs) dispersed in each bowl (denoted as Ag-NPs@Au-NB arrays) are achieved and utilized as effective surface-enhanced Raman scattering (SERS) substrates. The field enhancement benefiting from the special particle-in-cavity geometrical structure as well as the high density of SERS hot spots located in the sub-10 nm gaps between adjacent Ag-NPs and at the particle-cavity junctions all together contribute to the high SERS activity of the Ag-NPs@Au-NB arrays; meanwhile the ordered morphological features of the Ag-NPs@Au-NB arrays guarantee uniformity and reproducibility of the SERS signals. By modifying the Ag-NPs@Au-NB arrays with mono-6-thio-ß-cyclodextrin, the SERS detection sensitivity to 3,3('),4,4(')-tetrachlorobiphenyl (PCB-77, one congener of polychlorinated biphenyls (PCBs, kinds of persistent organic pollutants which represent a global environmental hazard)) can be further improved and a low concentration down to 5 × 10(-7) M can still be examined, showing promising potential for application in rapid detection of trace-level PCBs in the environment.

Ag-nanoparticles-decorated NiO-nanoflakes grafted Ni-nanorod arrays stuck out of porous AAO as effective SERS substrates.

NiO-nanoflakes (NiO-NFs) grafted Ni-nanorod (Ni-NR) arrays stuck out of the porous anodic aluminum oxide (AAO) template are achieved by a combinatorial process of AAO-confined electrodeposition of Ni-NRs, selectively etching part of the AAO template to expose the Ni-NRs, wet-etching the exposed Ni-NRs in ammonia to obtain Ni(OH)2-NFs grafted onto the cone-shaped Ni-NRs, and annealing to transform Ni(OH)2-NFs in situ into NiO-NFs. By top-view sputtering, Ag-nanoparticles (Ag-NPs) are decorated on each NiO-NFs grafted Ni-NR (denoted as NiO-NFs@Ni-NR). The resultant Ag-NPs-decorated NiO-NFs@Ni-NR (denoted as Ag-NPs@NiO-NFs@Ni-NR) arrays exhibit not only strong surface-enhanced Raman scattering (SERS) activity but also reproducible SERS-signals over the whole array. It is demonstrated that the strong SERS-activity is mainly ascribed to the high density of sub-10 nm gaps (hot spots) between the neighboring Ag-NPs, the semiconducting NiO-NFs induced chemical enhancement effect, and the lightning rod effect of the cone-shaped Ni-NRs. The three-level hierarchical nanostructure arrays stuck out of the AAO template can be utilized to probe polychlorinated biphenyls (PCBs, a kind of global environmental hazard) with a concentration as low as 5 × 10(-6) M, showing promising potential in SERS-based rapid detection of organic environmental pollutants.

Positive Emotions and Entrepreneurial Intention: The Mediating Role of Entrepreneurial Cognition.

Under the background of "mass entrepreneurship and innovation," entrepreneurship and innovation for college students not only alleviates the current social employment pressure but also sets off the upsurge of their entrepreneurship. It is a significant field to research the entrepreneurial intention of undergraduates as potential entrepreneurs, which covers the study of entrepreneurial intention from the perspective of personal traits and entrepreneurial cognition. This article studies entrepreneurial intention from two aspects: irrational positive emotions and rational entrepreneurial cognition, which aims to reveal the mechanism of positive emotions and entrepreneurial cognition on entrepreneurial intention. After investigating 288 college students participating in entrepreneurial competitions, establishing structural equations, and using SmartPLS software for data analysis, the research result showed that positive emotions significantly positively impact the three scripts of entrepreneurial cognition: arrangement scripts, willing scripts, and ability scripts. The arrangement, willing, and ability scripts positively influence entrepreneurial intention, while positive emotions do not affect entrepreneurial intention. Arrangement scripts and ability scripts have a full mediating effect between positive emotions and entrepreneurial intention. Based on these findings, we provide suggestions for the government and society, schools, and individual students on innovation and entrepreneurship.

Surface decoration of ZnO nanorod arrays by electrophoresis in the au colloidal solution prepared by laser ablation in water.

A simple and green strategy is presented to decorate ZnO nanorod array, based on electrophoresis deposition in the Au colloidal solution prepared by laser ablation in water and subsequent further laser irradiation. The surface of nanorods is homogeneously decorated with Au nanoparticles. The Au nanoparticles have good interfacial connection and strong binding with ZnO nanorods. The decoration morphology can be easily controlled by the size of Au colloids. Further experiments have revealed that suitable electrophoretic potential, small Au colloid's size, and enough inter-nanorod's spacing are crucial to formation of a homogeneous and strong surface decoration. Such Au nanoparticle-decorated ZnO nanorod array is functionalized and exhibits excellent surface-enhanced Raman scattering performance and shows the possibility of molecule-level detection. This study provides a new opportunity for the controllable surface modification of 1D semiconductor nanostructures and deepens the understanding of the physical mechanism of electrophoretic deposition.

Galvanic-Cell-Reaction-Driven Deposition of Large-Area Au Nanourchin Arrays for Surface-Enhanced Raman Scattering.

Here we report a low-cost synthetic approach for the direct fabrication of large-area Au nanourchin arrays on indium tin oxide (ITO) via a facile galvanic-cell-reaction-driven deposition in an aqueous solution of chloroauric acid and poly(vinyl pyrrolidone) (PVP). The homogeneous Au nanourchins are composed of abundant sharp nanotips, which can served as nanoantennas and increase the local electromagnetic field enhancement dramatically. Finite element theoretical calculations confirm the strong electromagnetic field can be created around the sharp nanotips and located in the nanogaps between adjacent tips of the Au nanourchins. In addition, the interparticle nanogaps between the neighboring Au nanourchins may create additional hotspots, which can induce the higher electromagnetic field intensity. By using rhodamine 6G as a test molecule, the large-area Au nanourchin arrays on ITO exhibit active, uniform, and reproducible surface-enhanced Raman scattering (SERS) effect. To trial their practical application, the Au nanourchin arrays are utilized as SERS substrates to detect 3,3’,4,4’-tetrachlorobiphenyl (PCB-77) one congener of polychlorinated biphenyls (PCBs) as a notorious class of persistent organic pollutants. The characteristic Raman peaks can be still identified when the concentration of PCB-77 is down to 5 × 10−6 M.

Nano-petri-dish array assisted glancing angle sputtering for Ag-NP assembled bi-nanoring arrays as effective SERS substrates.

Nano-petri-dish array assisted glancing angle Ag-sputtering was reported to synthesize Ag-nanoparticle (Ag-NP) assembled bi-nanoring arrays as surface-enhanced Raman scattering (SERS) substrates. By manipulating the sputtering-Ag duration, the gaps between the Ag-NPs in the bi-nanorings are tunable to acquire optimal electromagnetic field enhancement, and the ordered bi-nanoring arrays ensure excellent reproducibility for Raman measurement. Such as-fabricated Ag-NPs assembled nanoring arrays exhibit excellent SERS performance, not only 1 × 10(-12) M rhodamine 6G has been identified, but also polychlorinated biphenyls with a low concentration down to 1 × 10(-9) M has been recognized, showing great potential in the detection of trace organic pollutants in the environment.

Nanocontainers made of various materials with tunable shape and size.

Nanocontainers have great potentials in targeted drug delivery and nanospace-confined reactions. However, the previous synthetic approaches exhibited limited control over the morphology, size and materials of the nanocontainers, which are crucial in practical applications. Here, we present a synthetic approach to multi-segment linear-shaped nanopores with pre-designed morphologies inside anodic aluminium oxide (AAO), by tailoring the anodizing duration after a rational increase of the applied anodizing voltage and the number of voltage increase during Al foil anodization. Then, we achieve nanocontainers with designed morphologies, such as nanofunnels, nanobottles, nano-separating-funnels and nanodroppers, with tunable sizes and diverse materials of carbon, silicon, germanium, hafnium oxide, silica and nickel/carbon magnetic composite, by depositing a thin layer of materials on the inner walls of the pre-designed AAO nanopores. The strategy has far-reaching implications in the designing and large-scale fabrication of nanocontainers, opening up new opportunities in nanotechnology applications.

Au nanochain-built 3D netlike porous films based on laser ablation in water and electrophoretic deposition.

A green and controllable strategy is presented to fabricate homogeneous and Au nanochain-built three-dimensional netlike porous films based on electrophoretic deposition in the colloidal solution prepared by laser ablation in water.

Crystalline silicon nanotubes and their connections with gold nanowires in both linear and branched topologies.

Silicon, being in the same group in the periodic table as carbon, plays a key role in modern semiconductor industry. However, unlike carbon nanotube (NT), progress remains relatively slow in silicon NT (SiNT) and SiNT-based heteroarchitectures, which would be the fundamental building blocks of various nanoscale circuits, devices, and systems. Here, we report the synthesis of linear and branched crystalline SiNTs via porous anodic aluminum oxide (AAO) self-catalyzed growth and postannealing, and the connection of crystalline SiNTs and gold nanowires (AuNWs) via a combinatorial process of electrodepositing AuNWs with predesired length and location in the channels of the AAO template and subsequent AAO self-catalyzed and postannealing growth of SiNTs in the remaining empty channels adjacent to the AuNWs. Using the approach, a large variety of two-segment AuNW/SiNT and three-segment SiNT/AuNW/SiNT heteronanostructures with both linear and branched topologies have been achieved, paving the way for the rational design and fabrication of SiNT-based nanocircuits, nanodevices, and multifunctional nanosystems in the future.