Abstract: Vacancy defects are common defects formed in the syntheses of silicon carbide nanotubes (SiCNTs) and seriously impact the electronic structures of the nanotubes. With first-principle calculations based on density functional theory (DFT), vacancy defective (6,2) SiCNTs are studied. Vacancies form a pair of fivefold and ninefold rings. Carbon vacancy introduces an occupied defect level near the top of the valence band and an unoccupied level in the conduction band. Three defect levels are found in the band gap of the SiCNT with a silicon vacancy. These results are helpful for investigations on SiCNT devices and sensors.
Abstract: The novel solid NaXe nanoclusters were prepared. Measurements and calculations indicated that solid NaXe nanocluster has easily vibration- dissociated ground state and stable excited state to emit UV radiation. In the meanwhile the solid nanocluster NaXe retains fcc position within the host NaCl matrix. Therefore，the integrated ultraviolet(UV)-micro-excimer-laser-matrix can be prepared by using solid NaXe nanoclusters.
Abstract: SO42-/TiO2, SO42-/Fe2O3 nanoparticles were prepared by the impregnation precipitation method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS) results showed that the uniform size of SO42-/TiO2, SO42-/Fe2O3 nanoparticles with high purity, good dispersivity and particle size range from 50nm to 200nm. A comparative study between SO42-/TiO2 and SO42-/Fe2O3 nanoparticles applied in the photocatalytic experiment on unsymmetrical dimethylhydrazine (UDMH) wastewater was carried out.
Abstract: The incorporation of metal nanoparticles is not a new method, but remains a method not enough investigated in perovskite solar cells. Many others studies about organometal halide perovskite have been done to improve thin film photovoltaic devices efficiencies. This enhancement has been due to materials purity, surface passivation or surface area adsorbent but the main enhancement has been either by fast electron extraction or light harvester which allowed increasing the Photocurrent Density (Jsc). In many literatures, we find that Plasmon effect can improve the absorption of solar cells. In this study we used a sol-gel method to incorporate metal nanoparticles into TiO2 in perovskite solar cells and we investigated the absorption, interface matters and efficiency with gold nanoparticles (Au NPs) doped TiO2 perovskite solar cells. We consider they are many parameters that may have an effect on light absorption in perovskite solar cells using Au NPs doped TiO2, but the most enhancements are done either by reducing exciton binding energy or by a better crystalline surface.
Abstract: This paper reports a simple and versatile method with innovative application of photoresist film for fabricating ordered nanodot arrays with tunable structural parameters as large-area surface enhanced Raman scattering (SERS) substrate with high performance. The substrate is fabricated by evaporating Au on the regularly patterned aluminum template of pits arrays formed from the anodization of Al. A key point in our method is coating a photoresist layer on the fragile Au film to support the film before separating it from the Al template, which insures the integrity of the film on large area. Taking Rhodamine 6G as probing molecules, SERS spectra are investigated. The convenience of preparation as well as the high performance for the SERS signals makes the prepared substrates a promising candidate for SERS sensing or detecting.
Abstract: GO-PMMA solid was used to test its ability on absorbing the lead ion obtained from standard solution. Samples of the test solution were collected at 0 min, 10 min, 30 min, 50 min and 70 min. The results analyzed from ICP reveal that GO-PMMA solid could absorb lead (II) ion sup to 68.6%, which is 65.8% higher than the control setup, i.e. PMMA solid, at room temperature and pressure. The dry mass of GO-PMMA solid is around 119.82g and the mass after testing is around 124.21g. The ability of absorption could be easily refreshed by washing with ethanol and distillated water (80/20 v/v) several times. Structure of GO-PMMA solid was characterized by FRIR and optical microscope. The oxygen-containing functional groups and the rough surface of the GO-PMMA solid are determined to be the contributing factors of the adsorption of lead (II) ion onto GO-PMMA solid. The high removal efficiency of GO-PMMA suggests its adsorption capability on lead (II) ion and can be applied to remove lead (II) ions from water.
Abstract: Because of the different melting point, it is difficult to doped Ag element in ZnO film. Ag dopant can adjust the properties of ZnO materials. In this paper, we deposited Ag doped ZnO film using two step vapour evaporation method on c-plane sapphire substrate. The SEM image shows that the doped film was composed of small grain which compact in order and the Ag microwires was dispersed on the surface. The EDX graph proves that the Ag was indeed in the film. The XRD pattern reveals that the doped film has prefer orientation along the c-axis with wurtzite structure and the dopants have not effect the crystal quality.
Abstract: Synthesis of poly (1, 4-phenylene sulfide) (PPS) through oxidative polymerization seems promising to us. Comparing with current commercial method to poly (1, 4-phenylene sulfide) from 1, 4-phenylene sulfide and sodium sulfide (Phillips’ Method), there are many advantages of the oxidative polymerization method. For example, it can synthesize PPS at normal temperature and pressure; the yield of reaction is very high; it provides pure PPS without salt contamination. However, several years have passed away; synthesis of poly (1, 4-phenylene sulfide) through oxidative polymerization has not so far been adopted as the industrial process. Many of us are puzzled, why? Through studying all kinds of reported preparation route to poly (1, 4-phenylene sulfide) through oxidative polymerization compared to Phillips’ Method, a generic polymerization mechanism is achieved for most of them excepting two with obvious shortcomings. We suddenly realize that synthesis of poly (1, 4-phenylene sulfide) through oxidative polymerization seems unsuitable to be used in industrial production recently because of its own limits.
Abstract: The narrow particle size distribution of poly (vinyl silicone) microspheres were prepared by the hydrolysis-polycondensation method with vinyl silane (VTMS) as raw materials. And the influences of pH value, oil/water ratio on the morphology, particle size and distribution of the microspheres were studied. The results shows that the particle size of microspheres decrease with the increasing of the PH value of polymerization, and the particle size has no specific linear relationship with the PH value of hydrolysis reaction, while the oil-water ratio is smaller, single particle size distribution is more narrow, more uniform distribution.