Growing ordered arrays of vertically aligned copolymer nanowires for supercapacitors with high stability

Journal of Solid State Electrochemistry - In this report, we present a novel platform to study the formation of delicate ordered vertically aligned copolymer nanowires array with EDOT and Py as the...     

Structural,magnetic and optical properties of vanadium doped zinc oxide: Systematic first-principles investigations

The electronic structural, magnetic and optical properties of pure and V-doped ZnO are investigated by first-principles calculations based on the density functional theory. With the introduction of V atoms, the spin-splitting near the Fermi level leads to a net magnetic moment of the system. A significant possibility of room temperature ferromagnetism (RTFM) originated from the Ruderman–Kittel–Kassuya–Yosida (RKKY) exchange is predicted. Oxygen vacancy is positive to enhance the ferromagnetism while zinc vacancy is negative. With respect to the optical properties, the presence of V atoms was found to have an obvious influence on the transmittivity, especially in the low energy region. A slight V-doping can keep a high optical transmission and smoothly modulate the optical bandgap.     

Photocatalytic and optical properties of titanium dioxide thin films prepared by metalorganic chemical vapor deposition

Titanium dioxide thin films have been deposited by metalorganic chemical vapor deposition (MOCVD) over sodalime glass substrates at substrate temperatures ranging from 250 °C to 450 °C. The effect of deposition temperature on the structure and microstructure of the obtained films has been studied by x-rays diffraction (XRD) and scanning electron microscopy (SEM), respectively. Diffraction patterns show the existence of a pure anatase phase beside a texture change with the increase of deposition temperature. Micrographs show grain fragmentation with the increase in deposition temperature. UV–Vis. spectra have been recorded by spectrophotometery. The optical energy gap has been calculated for the deposited films from the spectrophotometrical data. Photocatalytic experiments have been carried out. The photocatalytic activity has been found to decrease with the increase in deposition temperature.     

On the Role of Alkali-Metal-Like Superatom Al12P in Reduction and Conversion of Carbon Dioxide

Developing efficient catalysts for the conversion of CO₂ into fuels and value-added chemicals is of great significance to relieve the growing energy crisis and global warming. With the assistance of DFT calculations, it was found that, different from Al₁₂X (X=Be, Al, and C), the alkali-metal-like superatom Al₁₂P prefers to combine with CO₂ via a bidentate double oxygen coordination, yielding a stable Al₁₂P(η²-O₂C) complex containing an activated radical anion of CO₂ (i.e., CO₂^.−). Thereby, this compound could not only participate in the subsequent cycloaddition reaction with propylene oxide but also initiate the radical reaction with hydrogen gas to form high-value chemicals, revealing that Al₁₂P can play an important role in catalyzing these conversion reactions. Considering that Al₁₂P has been produced in laboratory and is capable of absorbing visible light to drive the activation and transformation of CO₂, it is anticipated that this work could guide the discovery of additional superatom catalysts for CO₂ transformation and open up a new research field of superatom catalysis.     

White-light-emitting diodes using GaN-excited CdSe/CdS/ZnS quantum dots

Fluorescence-based white-light-emitting diodes (WLEDs) were fabricated using blue GaN chips and green- and red-emitting CdSe/CdS/ZnS quantum dots (QDs). The coordinate and color temperature of the WLEDs could be varied because of the size-tunable emission of CdSe QDs from 510 to 620 nm. Warm and cold white emissions were confirmed with the color temperature ranging from 4000 to 9000 K. Color coordinates were analyzed at different bias. The fast enhancement of blue emission resulted in the shift of color coordinates to the cold side. The stability of white emission during operation was analyzed; stable spectra were achieved within 90 min.     

Fabrication,Characterization and Optical Properties of TiO2 Nanotube Arrays on Boron-doped Diamond Film Through Liquid Phase Deposition

TiO2 nanotube（TiNT） arrays were deposited on boron-doped diamond films by a liquid-phase deposition method with ZnO nanorod arrays as the template.The different morphologies of TiNTs have been obtained by controlling the morphology of ZnO template.The X-ray diffraction and energy-dispersive X-ray analysis show that the ZnO nanorod array template has been removed in the TiNTs formation process.The crystalline quality of the TiNTs is improved by increasing the annealing temperature.The band gap of the TiNTs is about 3.25 eV estimated by the UV-Vis absorption spectroscopy,which is close to the value of bulk TiO2.In the photoluminescence spectrum,a broad visible emission in a range of ca.550-750 nm appears due to the surface oxygen vacancies and defects.     

Application of monodisperse TiO2 nanoparticles with the size of 8–10 nm in dye-sensitized solar cells

In this paper, the commercial monodisperse TiO₂ nanoparticles with the size of 8–10 nm were successfully applied to the photoelectrode for dye-sensitized solar cells (DSCs) and the influence of the thickness of the TiO₂ thin films on the photovoltaic performance of the DSCs was investigated. The result revealed that the DSCs with the TiO₂ thin film thickness of 3.6, 8.0, 11.6 and 20.0 μm gave the photoelectric conversion efficiency of 3.67%, 5.92%, 6.71% and 7.03%, respectively, under the illumination of simulated AM 1.5 sunlight (100 mW cm⁻²).     

A simple and efficient method for the allylation of heteroarenes catalyzed by PdCl2

The PdCl₂-catalyzed allylation of heteroarenes is presented. Various heteroarenes including O-, N-, and S-based ones were allylated efficiently with a rich range of allylic acetates in the presence of only 2 mol % of PdCl₂, without the need of bases/acids, additives, and external supporting ligands. In addition, the reactions were carried out under mild and simple conditions just by stirring the two reactants and catalyst in CH₂Cl₂ at 60 °C. Moreover, the by-product produced was non-toxic acetic acid. Thus, the method presented in this work provides a general, clean, and operationally simple approach for the functionalization of heteroarenes. Finally, a preliminary mechanistic study suggested that the Pd(II) may be reduced in situ by the heteroarenes to Pd(0), which serves as the active metal center to catalyze the following allylations of heteroarenes via a Tsuji–Trost pathway.