Polarity-Free Epitaxial Growth of Heterostructured ZnO/ZnS Core/Shell Nanobelts

Surface-polarity-induced formation of ZnO/ZnS heterojunctions has a common characteristic that ZnS (or ZnO) is exclusively decorated on a Zn-terminated (0001) surface of ZnO (or ZnS) due to its comparatively chemically active nature to an O (or S)-terminated (000–1) surface. Here, we report a polarity-free and symmetrical growth of ZnS on both ZnO±(0001) surfaces to form a new heterostructured ZnO/ZnS core/shell nanobelt via a thermal evaporation method. Remarkably, the ZnS shell is single-crystalline and preserves the structure and orientation of the inner ZnO nanobelt with an epitaxial relationship of (0001)_ZnO//(0001)_ZnS; [2–1–10]_ZnO//[2–1–10]_ZnS. Through this case, we demonstrate that an anion-terminated polar surface could also drive the nucleation and growth of nanostructures as the cation-terminated surface by controlling the growth kinetics. Considering high-performance devices based on ZnO/ZnS heterojunctions, the current ZnO/ZnS nanobelt is advantageous for optoelectronic applications due to its single-crystalline nature and relatively more efficient charge separation along 3D heterointerfaces

Assembly of Three-Dimensional Hetero-Epitaxial ZnO/ZnS Core/Shell Nanorod and Single Crystalline Hollow ZnS Nanotube Arrays

Hetero-epitaxial growth along three-dimensional (3D) interfaces from materials with an intrinsic large lattice mismatch is a key challenge today. In this work we report, for the first time, the controlled synthesis of vertically aligned ZnO/ZnS core/shell nanorod arrays composed of single crystalline wurtzite (WZ) ZnS conformally grown on ZnO rods along 3D interfaces through a simple two-step thermal evaporation method. Structural characterization reveals a “(01–10)_ZnO//(01–10)_ZnS and [0001]_ZnO//[0001]_ZnS” epitaxial relationship between the ZnO core and the ZnS shell. It is exciting that arrays of single crystalline hollow ZnS nanotubes are also innovatively obtained by simply etching away the inner ZnO cores. On the basis of systematic structural analysis, a rational growth mechanism for the formation of hetero-epitaxial core/shell nanorods is proposed. Optical properties are also investigated <i>via</i> cathodoluminescence and photoluminescence measurements. Remarkably, the synthesized ZnO/ZnS core/shell heterostructures exhibit a greatly reduced ultraviolet emission and dramatically enhanced green emission compared to the pure ZnO nanorods. The present single-crystalline heterostructure and hollow nanotube arrays are envisaged to be highly promising for applications in novel nanoscale optoelectronic devices, such as UV-A photodetectors, lasers, solar cells, and nanogenerators

Synthesis, crystal structures and photoluminescent properties of two Cd(II)/Zn(II) coordination polymers with rarely 8-/2-fold interpenetrated based on 4,4′-stilbenedicarboxylic acid and imidazole ligands

<p>Two coordination polymers, [Cd(sbdc)(bmib)]_n (<b>1</b>) and {[Zn(sbdc)(tib)]·0.5H₂O}_n (<b>2</b>) (H₂sbdc = 4,4′-stilbenedicarboxylic, bmib = 1,4-bis(2-methylimidazol-1-yl)butane, tib = 1,3,5-tris(1-imidazolyl)benzene), have been synthesized under solvothermal conditions, characterized by elemental analysis, infrared spectra, thermogravimetric analysis, and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that <b>1</b> and <b>2</b> show 8-fold and 2-fold interpenetrating 3-D frameworks, respectively. Complexes <b>1</b> and <b>2</b> display a 4-connected (6⁶) <b>sqc6</b> and a 4-connected (4⁴·6²) <b>sql</b> topology, respectively. Photoluminescent and thermal properties of <b>1</b> and <b>2</b> have also been investigated.</p

Silicon/Hematite Core/Shell Nanowire Array Decorated with Gold Nanoparticles for Unbiased Solar Water Oxidation

We report the facile fabrication of three-dimensional (3D) silicon/hematite core/shell nanowire arrays decorated with gold nanoparticles (AuNPs) and their potential application for sunlight-driven solar water splitting. The hematite and AuNPs respectively play crucial catalytic and plasmonic photosensitization roles, while silicon absorbs visible light and generates high photocurrent. Under simulated solar light illumination, solar water splitting with remarkable efficiency is achieved with no external bias applied. Such a nanocomposite photoanode design offers great promise for unassisted sunlight-driven water oxidation, and further stability and efficiency improvements to the device will lead to exciting prospects for practical solar water splitting and artificial photosynthesis

Metal-Catalyzed Electroless Etching of Silicon in Aerated HF/H₂O Vapor for Facile Fabrication of Silicon Nanostructures

Inspired by metal corrosion in air, we demonstrate that metal-catalyzed electroless etching (MCEE) of silicon can be performed simply in aerated HF/H₂O vapor for facile fabrication of three-dimensional silicon nanostructures such as silicon nanowires (SiNW) arrays. Compared to MCEE commonly performed in aqueous HF solution, the present pseudo gas phase etching offers exceptional simplicity, flexibility, environmental friendliness, and scalability for the fabrication of three-dimensional silicon nanostructures with considerable depths because of replacement of harsh oxidants such as H₂O₂ and AgNO₃ by environmental-green and ubiquitous oxygen in air, minimum water consumption, and full utilization of HF

Phosphorylation levels of K_V4.3 and K_V2.2 in normal, sham, and obstruction groups.

<p>Phosphorylation of Kv4.3 and Kv2.2 were examined by immunoprecipitation (IP) with ant-Kv4.3 antibody followed by IB with antibody against p-threonine, p-serine and Kv4.3 or IP with anti- Kv2.2 antibody followed by IB with antibody against p-threonine, p-serine and Kv2.2 (A). Corresponding bands were scanned and the phosphorylation band optical density was normalized by the total protein density. Data were the means ± SD and were expressed as folds versus normal. *<i>P</i><0.05 versus normal and sham, n = 5 (B).</p

Kv4.3 and Kv2.2 expressions of intestinal smooth muscle tissues in normal, sham, and obstruction groups.

<p>A shows the westernblot bands performed with anti-Kv4.3 or anti- Kv2.2 antibodies to detect the Kv4.3 and Kv2.2 expression levels. GAPDH was used as internal control to normalize for difference in loading. Corresponding bands were scanned and the Kv4.3 or Kv2.2 band optical density was normalized by the GAPDH protein density. Data showed the means ± SD, n = 6, *<i>P</i><0.05 versus sham groups (B).</p

Changes of slow wave and resting membrane potential (RMP) in hypertrophic smooth muscles.

<p>Electrical slow waves were recorded from small intestinal muscle stripes of normal group (Aa), sham group (Ab), and obstruction group (Ac). The RMP (Ba), amplitudes (Bb) and frequencies (Bc) of slow wave were significantly changed in normal, sham and obstruction groups. Data showed the means ± SE *<i>P</i><0.01 versus sham and normal groups.</p

Comparison of IK_V in normal sham and obstruction groups.

<p>A shows representative current traces elicited from a holding potential of −60 mV using voltage steps of 400 ms from −40 mV to +100 mV in 20 mV increments. Interval between each pulse is 10 s. Averaged current density-voltage relation of IK_Vpeak (B) and IK_Vsustained (C) plotted for the smooth muscle cells from normal, sham, and obstruction groups. Data showed the means ± SE *<i>P</i><0.01 versus sham and normal groups.</p

The hypertrophy of smooth muscle cells induced by partial intestinal obstruction.

<p>A shows normal (a) and hypertrophic smooth muscle cells (b), the cell size was significantly enlarged in obstruction group. B shows the mean values of cell capacitances among normal, sham and obstruction groups. Data showed the means ± SE *P<0.01 versus sham and normal groups, *<i>P</i><0.05 versus normal and sham group, Bar = 100 µm.</p