Investigation of waveguide and process parameter of nonlinear optical waveguide in CdS_xSe_(1-x)doped glass

For the first time,it is experiementally verified that the index profile of K~ —Na~ ion-exchanged waveguide in CdS_xSe_(1-x)doped glass follows a second-order polynomial dis-tribution.Mode-dispersion curves have been obtained by computing simplified mode equationin WKB approximation and verified by experiment.Diffusion constant has been measured ac-curately.Technical basis is provided for the design and fabrication of all-optical switching de-vices in this kind of nonlinear waveguide.     

碳点修饰多孔ZnO纳米棒增强光催化性能

Porous ZnO nanorods that displayed excellent photocatalytic degradation of organic pollutants (RhB and phenol) were prepared via a solvent thermal method followed by surface modification with carbon dots (C-dots) using a deposition method. The photocatalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible (UV-Vis) spectroscopy. The degradation of the organic pollutants using the nanorods was tested under Xe-light illumination and was enhanced following C-dot modification. Nanorods that were modified by the C-dots at a mass fraction of 1.2% (CZn1.2) exhibited the highest photocatalytic activity for the degradation of RhB, which was 2.5 times of the pure porous ZnO nanorods. Additionally, the modified nanorods with strangely oxidation ability could catalyze the degradation of phenol by open-rings reaction under Xe-light illumination. The improved photocatalytic activity was attributed to the effective separation of the photogenerated electrons and holes, in which the C-dots served as the receptor of the photogenerated electrons.     

铒掺杂硼酸盐玻璃中的激发态阱

铒掺杂硼酸盐玻璃广泛应用于发光材料中,研究其发光动力学性质对于优化和提高其发光效率具有重要意义. 本文采用传统的熔融淬火法合成了摩尔比为2%的掺铒硼酸盐玻璃,并在低于硼酸盐玻璃转变温度(260 °C)下退火,退火处理后的掺铒硼酸盐玻璃光学性质得到了一定程度的提高. 硼酸盐玻璃未掺杂和掺杂Er³⁺的热性能采用差示扫描量热法以10 °C/min的速度进行测量. 同时还测量了掺铒硼酸盐玻璃发光机理的吸收光谱、激发光谱、稳态发射光谱、瞬态发射光谱和衰减动力学曲线. 实验结果表明Er³⁺在不同激发波长下556 nm处发射时具有不同的寿命,在掺铒硼酸盐玻璃中可能存在激发态阱,利用实验数据得到了激发态阱的深度为0.14 eV.     

Three-dimensional vertical ZnO transistors with suspended top electrodes fabricated by focused ion beam technology

Three-dimensional(3D)vertical architecture transistors represent an important technological pursuit,which have distinct advantages in device integration density,operation speed,and power consumption.However,the fabrication processes of such 3D devices are complex,especially in the interconnection of electrodes.In this paper,we present a novel method which combines suspended electrodes and focused ion beam(FIB)technology to greatly simplify the electrodes interconnection in 3D devices.Based on this method,we fabricate 3D vertical core-double shell structure transistors with ZnO channel and Al₂O₃ gate-oxide both grown by atomic layer deposition.Suspended top electrodes of vertical architecture could be directly connected to planar electrodes by FIB deposited Pt nanowires,which avoid cumbersome steps in the traditional 3D structure fabrication technology.Both single pillar and arrays devices show well behaved transfer characteristics with an Ion/Ioff current ratio greater than 106 and a low threshold voltage around 0 V.The ON-current of the 2×2 pillars vertical channel transistor was 1.2μA at the gate voltage of 3 V and drain voltage of 2 V,which can be also improved by increasing the number of pillars.Our method for fabricating vertical architecture transistors can be promising for device applications with high integration density and low power consumption.     

High-quality CdS quantum dots sensitized ZnO nanotube array films for superior photoelectrochemical performance

The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod (NR) array films as the template. Benefiting from the etching and regrowth process and the different structural stabilities of the various faces of ZnO NRs, the uniquely etched and W-doped ZnO (EWZ) nanotube (NT) array films with larger surface area, more active sites and better energy band structure were used to improve the photoelectrochemical (PEC) performance and the loading quality of CdS quantum dots (QDs). On the basis of their better surface characteristics, the CdS QDs were uniformly loaded on EWZ NT array film with a good coverage ratio and interface connection; this effectively improved the light-harvesting ability, charge transportation and separation as well as charge injection efficiency during the PEC reaction. Therefore, all the CdS QD-sensitized EWZ NT array films exhibited significantly enhanced PEC performance. The CdS/EWZ-7 composite films exhibited the optimal photocurrent density with a value of 12 mA· cm^-2, 2.5 times higher than that of conventional CdS/ZnO-7 composite films under the same sensitization times with CdS QDs. The corresponding etching and optimizing mechanisms were also discussed.     

Preparation and evaluation of thermally stable nano-structured self-doped polythiophene coating for analysis of phthalate ester trace levels

Nano‐structured self‐doped polythiophene (SPT) electrodeposited in the presence of fluorinated organic acid was applied as a thermally stable conductive polymer‐based solid‐phase microextraction (SPME) fiber candidate. Quantitative determination of trace levels of phthalate esters including dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and diethylhexyl phthalate (DEHP) was carried out using this novel fiber, coupling with gas chromatography‐flame ionization detector (GC‐FID). The SPT coating was proved to be stable at high temperatures (～350°C) with a high extraction capacity and long lifetime (more than 60 times). Improved temperature resistance was obtained by the presence of sulfonated groups in the backbone of polymer. Thermal stability of novel SPT was superior to common polythiophene (synthesized in LiClO₄). The extraction procedure was optimized by means of the Taguchi orthogonal array experimental design with an OA₁₆ (4⁵) matrix including extraction temperature, extraction time, salt concentration, stirring rate, and headspace volume. The good linearity was obtained for most compounds with correlation coefficients (R²) of between 0.993 and 0.995. The detection limits were lower than 0.12 ng/mL for dimethyl phthalate, DEP, dibutyl phthalate, and diethylhexyl phthalate. The method was successfully applied to the analysis of water samples with the recoveries from 90±1 to 107±1%.     

掺铒联吡啶钌为探针分子压敏漆的制备及氧猝灭特性

以2,2′-联吡啶,三氯化钌(RuCl3),氯化铒(ErCl3)为原料合成了铒掺杂的探针分子。将探针分子加入到铕掺杂的硅溶胶基质中获得了铕、铒共掺杂的压敏漆样品。采用IR,SEM,EDS及荧光发射光谱对探针分子和压敏漆进行了表征。红外光谱结果表明,探针分子中联吡啶的结构没有被破坏。扫描电镜观察发现探针分子呈片状,EDS测试发现探针分子表面含有Er,Ru等元素。紫外吸收光谱表明压敏漆的最佳吸收波段位于200~500 nm处,选择410 nm作为激发光源,压敏漆在590 nm处有很强的荧光发射,并且随着空气压力的增大(即氧分子浓度的增加),压敏漆的荧光发射强度降低,说明压敏漆具有较好的氧猝灭特性。     

花状ZnO/ZnS异质结构的简易合成、结构表征及光催化活性

采用简便的两步溶液相化学方法,在较低温度下(80℃),制备出了花状的ZnO/ZnS异质结构。分别利用X射线衍射、X射线光电子能谱仪、扫描电子显微镜、透射电子显微镜、紫外-可见光谱仪等测试手段对所制备的样品进行表征,结果表明ZnO/ZnS异质结构是由花状ZnO纳米结构和ZnS纳米粒子组成。在光降解罗丹明B(RhB)的测试中,ZnO/ZnS异质结构样品体现出了比ZnO前驱物和商业P25光催化剂更高的光催化效率,这主要可归因于异质结构更有利于电子-空穴的有效分离。ZnO/ZnS光催化剂体现出良好的循环稳定性。     

Synthesis,Characterization, Antibacterial and Antifungal Activity of Yttrium(III) Complexes Including 1,10‐Phenanthroline

Two rare metal coordination complexes of yttrium(III) including 1,10‐phenanthroline, Y(phen)₂(NO₃)₃ and (phenH)₂[Y₂(pydc)₃(NO₃)₂·6H₂O] (phen=1,10‐phenanthroline, pydc=2,6‐pyridinedicarboxylate), and a proton transfer compound (phenH⁺)₂(pydc^2?) were synthesized and characterized by elemental analysis, molar conductance, infrared spectra (IR), nuclear magnetic resonance (NMR) and thermal analysis. The proposed structures of yttrium complexes were exhibited. The in vitro biological activities of the newly synthesized complexes have also been investigated against Bacillus coli, Staphylococcus aureus and Candida albicans. The results showed that yttrium(III) complexes including 1,10‐phenanthroline exhibited better antibacterial/antifungal activity than their ligands and corresponding compounds.     

Zinc oxide nanoparticles:A highly efficient and readily recyclable catalyst for the synthesis of xanthenes

A novel and efficient route for the synthesis of 1,8-dioxooctahydroxanthenes and 14-aryl-14H-dibenzo[a,j]xanthenes is described through one-pot multi-component reaction of dimedone and 2-naphthol with various aryl aldehydes using ZnO nanoparticles under solvent-free conditions.This method provides a novel and improved pathway for the synthesis of xanthenes in the terms of excellent yields,short reaction times,reusability and low catalyst loading.