微纳米晶CuInSe_2溶剂热合成与表征

以硝酸铟、硝酸铜及硒粉为原料,以乙醇胺和无水乙醇作为溶剂,采用溶剂热法合成了铜铟硒(CuInSe2,简称为CIS)微纳米晶,通过单因素实验方法考察了原料的物质的量比、反应时间、反应温度等因素对产物的影响,得出了制备CuInSe2纳米晶粉末的适宜条件。通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、紫外可见吸收(Uv-Vis)等方法对产物进行表征和测试。     

不同形貌低维纳米/微米CdSe/ZnSe的溶剂热法合成

利用溶剂热法,通过添加不同种类的溶剂及改变反应温度、反应时间,成功合成了具有片状、棒状、球状、圆锥花序状等不同形貌的纳米/微米级硒化镉、硒化锌半导体材料.简单讨论了表面活性剂、反应温度及反应时间对产物形貌及尺寸的影响.所得产物进行了扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱(EDS)、X射线衍射(XRD)等表征.     

不同形貌低维纳米／微米CdSe／ZnSe的溶剂热法合成

利用溶剂热法．通过添加不同种类的溶剂及改变反应温度、反应时间．成功合成了具有片状、棒状、球技，圆锥花序状等不同形貌的纳米/微米级硒化镉、硒化锌半导体材料.简单讨论了表面活性剂、反应温度及反应时间对产物形貌及尺寸的影响。所得产物进行了扫描电子显微镜（SEM）、透射电子显微镜（TEM）、能谱（EDS）、X射线折射（XRD）等表征.     

硒化银纳米颗粒和晶体的制备及其表征

以氯化纳和硒粉为原料,乙二胺为反应溶剂,通过室温合成法制备了硒化银（Ag2Se）纳米颗粒,并首次利用固相反应法,在300℃～600℃烧结范围合成了晶体。结合X射线粉末衍射（XRD）、扫描电镜SEM及透射电镜（TEM）分别对反应产物的相结构和形貌进行了表征。结果表明,室温合成法所得产物为高纯度的正交仪相Ag2Se纳米颗粒,其表面光滑,呈球形;固相反应法合成的样品保持了正交相结构,且Ag与Se的化学计量比基本满足2：1。     

超声方法合成硒纳米线（英文）

用超声的方法合成了硒纳米线.场发射扫描电镜（FESEM）结果表明产物的形貌比较均一.产物的结构通过透射电镜（TEM）和X-射线衍射仪（XRD）进行了进一步表征.TEM和XRD光谱的结果证明了所得硒纳米线为单晶结构且沿着[001]方向生长.所得硒纳米线在671nm处有一紫外光谱吸收峰,通过对光谱的计算,硒纳米线的能带为1.66eV.基于一系列的生长过程,提出了硒纳米线的生长机理：硒粉溶解溶液中产生自由硒原子;当硒原子浓度过高时,硒原子结晶形成t型硒种子;由于各向异性晶体结构,连续提供的硒原子进入结晶种子形成线性纳米结构.此外,溶解和再结晶使α型硒转化为更稳定的t型硒.超声波可以提供适当的能量来调整这动态的平衡溶解和再结晶,进一步加快这一转变.     

反向溶液法制备硒纳米纤维正极的电化学性能研究

采用简单的反向溶剂法制备出了直径为100 nm左右的高纯、高结晶度的纳米纤维状硒, 采用X射线粉末衍射仪、扫描电子显微镜对纤维硒进行结构和形貌的表征。硒纤维电极由于减小了单质硒的尺寸, 因而减缓不导电放电产物Li₂Se在活性物质Se表面附着所引起的“钝化”作用, 从而大大提高了活性物质利用率, 减缓了普通硒电极的容量衰减。与普通硒正极相比, 硒纤维正极具有更高的比容量和循环稳定性, 0.1C(1C=675 mAh/g)倍率下首周放电比容量达到465 mAh/g, 40周后容量保持在213 mAh/g。同时由于缩短了锂离子的扩散路径, 硒纤维电极比普通硒电极具有更高的电化学活性, 其倍率性能得到了大幅提高。     

纳米金属氧化物制备多晶Cu(In,Ga)Se2薄膜反应过程及其性能研究

以铜铟镓纳米金属氧化物为起始原料, 采用化学还原+固体硒源后硒化的方法在不锈钢表面制备出多晶Cu(In,Ga)Se₂ (CIGS)薄膜。采用场发射扫描电镜、高分辨透射电镜、能谱分析和X射线衍射等方法对制备过程中材料组成和结构的演变进行了研究, 采用霍尔效应测试仪和吸收光谱分析等对多晶CIGS薄膜的性能进行了表征。研究结果表明, 纳米金属氧化物主要含CuO、In₂O₃、Ga₂O₃和铜-铟、铜-镓二元合金氧化物等成分, 在还原反应中逐渐转变成Cu₁₁In₉、Cu₉In₄等产物, 同时薄膜中形成大量孔隙; 硒化过程中, 硒蒸气沿孔隙通道进入还原产物的晶格, 反应生成CIS和CGS, 从而形成具有黄铜矿结构的多晶CIGS薄膜; 多晶CIGS薄膜表面晶粒排列紧密, 属于p型半导体, 其载流子浓度为2.3×10¹⁵ cm^-3, 迁移率为217 cm²/(V·s), 电阻率为36 Ω·cm, 带隙宽度约为1.15 eV。     

热蒸发法制备ZnSe纳米球及其球形度北大核心CSCD

使用硒化锌粉末,在一定条件下,采用热蒸发法制备出纳米结构的ZnSe纳米球,分析了添加少量硒粉对纳米球球径及球形度的影响,利用透射电镜及能谱仪观察了ZnSe纳米球的球径大小与分布,同时进行了元素分析,利用X射线衍射分析对ZnSe纳米球进行了物相鉴定。实验结果表明:控制蒸发电流在30 A,蒸发时间为3 s时,可以得到较好的ZnSe纳米球,而添加0.005 g硒粉时,得到的纳米球更小,球形度更好,表明在真空状态下,采用热蒸发法是一种制备ZnSe纳米球结构的有效新方法。     

纳米红色硒粉在乙二醇介质中的分散工艺研究北大核心CSCD

针对含纳米红色硒粉抗菌保健不锈钢餐具的开发问题,为制备高分散性和悬浮稳定性的纳米硒粉,本文在测定纳米硒粉在乙二醇介质中pH-zeta电位图的基础上,选用CTAB、PVP、PEG-2000和Span80四种表面活性剂,采用吸光度测试、沉降实验研究了纳米硒粉在乙二醇介质中的分散工艺及其悬浮稳定性,并探讨了不同表面活性剂的分散机理。结果表明,在最佳配比下的CTAB与具有空间位阻稳定机理PVP和PEG-2000的复合分散体系的分散效果明显好于单分散剂,其中,PVP与CTAB的复合分散比最佳单分散剂CTAB的分散效果提升了105%;推荐纳米硒粉在乙二醇中的分散工艺为:在pH=6、3%(质量比)CTAB+3%PVP复配分散,分散时间为10 min,该工艺下分散的纳米硒粒子静置60天的沉降率仅为0.7%。红外测试表明,CTAB在纳米硒粉表面为物理吸附,PVP、PEG-2000和Span80则为化学吸附。     

热蒸发法制备ZnSe纳米球及其球形度

使用硒化锌粉末,在一定条件下,采用热蒸发法制备出纳米结构的ZnSe纳米球,分析了添加少量硒粉对纳米球球径及球形度的影响,利用透射电镜及能谱仪观察了ZnSe纳米球的球径大小与分布,同时进行了元素分析,利用X射线衍射分析对ZnSe纳米球进行了物相鉴定。实验结果表明:控制蒸发电流在30 A,蒸发时间为3 s时,可以得到较好的ZnSe纳米球,而添加0.005 g硒粉时,得到的纳米球更小,球形度更好,表明在真空状态下,采用热蒸发法是一种制备ZnSe纳米球结构的有效新方法。     

Riley oxidation: A forgotten name reaction for synthesis of selenium nanoparticles

A simple wet chemical method, involving reaction of acetone with selenium dioxide, has been developed, to synthesize polyvinyl alcohol-stabilized selenium nanoparticles. The method is capable of producing nanoparticles in the size range of about 100-300 nm, under ambient conditions. The synthesized nanoparticles can be separated easily from the aqueous sols by a high-speed centrifuge, and can be re-dispersed in aqueous medium by a sonicator. The effect of concentrations of selenium dioxide, acetone and PVA on the size of the selenium nanoparticles has been studied. The size of the selenium nanoparticles has been found to increase with increase in the reaction time as well as the concentration of selenium dioxide, while it decreases with increase in the concentration of the stabilizer, PVA. The synthesized selenium nanoparticles have been characterized by UV-visible optical absorption spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, differential scanning calorimetry, atomic force microscopy, scanning electron microscopy and transmission electron microscopy techniques.     

Microstructural,optical and electrical investigations of large scale selenium nanowires prepared by template electrodeposition

Large scale selenium nanowires have been prepared into the pores of polycarbonate track-etched membrane by template electrodeposition. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–Visible spectroscopy have been used to characterize as-prepared crop of selenium nanowires. XRD and FESEM studies confirmed the formation of dense crop of selenium nanowires with trigonal phase. The spectra exhibited a highly crystalline peak corresponding to (100) plane suggesting a preferential growth along [001] direction. Williamson–Hall analysis has been used to determine the crystallite size and micro strain induced due to lattice deformation. The band gap of as-prepared selenium nanowires has been found to be 1.76 eV and of the direct type of transition. The blue shift observed in the optical band gap of selenium nanowires has been attributed to quantum size effect in semiconductor nanowires. Electrical properties of selenium nanowires have been examined using two probe method and showed double diode like current–voltage characteristics. The possible reaction mechanism of the formation of selenium nanowires has also been discussed.     

Mechanism of selenium pink colouration in glass

The mechanism of pink colouration with selenium in glass has been studied. When selenium-containing glasses are melted under reducing conditions, loss of selenium from the melt is decreased but a dark brown colour results due to the iron-selenide-oxide complex formation. Even a small amount of CeO₂ in the batch oxidizes selenium and bleaches the pink colour; large concentrations of arsenic oxide in the batch also have the same effect. Oxidizing conditions in the melt do not produce any larger selenium loss from the melt than that with “neutral” melting conditions. On electron microscope examination, pink glasses coloured with selenium revealed spherical particles. Mie's scattering curves due to spherical selenium particles of different average sizes and size distributions have been calculated and the experimental absorption bands of pink selenium glasses have been shown to be consistent with elemental selenium particles of average diameter 50 to 250 nm with large size distributions.     

A novel route to controlled synthesis of selenium nanowires

Trigonal selenium nanorods have been synthesized by sonicating the mixture of ethylenediamine, selenium powder, and water. The diameter of selenium nanowires can be controlled by the concentration of selenium; the length of selenium nanowires can be controlled by the reaction time.     

原子荧光光谱法测定新疆雪菊中微量硒

原子荧光光谱法测定雪菊中微量硒,对原子荧光光谱法的参考测试条件进行了优化,具有操作简单、快速、灵敏度高等优点,方法检出限为0.3μg/L,相关系数为：0.999971,测定雪菊花中硒的回收率为94-103%,RSD=0.20%,用国家标准物质对结果的准确性进行了验证,测定结果是满意。     

Tuning the internal structures of CdSeS nanoparticles by using different selenium and sulphur precursors

Alloyed CdSeS nanoparticles (NPs) with composition gradient and homogeneous internal structures have been successfully prepared in aqueous solution by using different selenium and sulphur precursors. The as-prepared NPs form a homogeneous internal structure when sodium selenide and sodium sulphide were used as selenium and sulphur precursors, respectively. Gradient internal structures were obtained for alloyed CdSeS NPs prepared by using sodium selenosulphate and sodium thiosulphate as selenium and sulphur precursors, respectively. The method takes advantage of the fact that different selenium/sulphur sources release selenium/sulphur ions at different rates or have different reaction rates of selenium/sulphur toward cadmium.     

Ionic liquid-induced synthesis of selenium nanoparticles

A simple wet chemical method has been used to synthesize selenium nanoparticles by the reaction of ionic liquid with sodium selenosulphate, a selenium precursor, in the presence of polyvinyl alcohol stabilizer, in aqueous medium. The method is capable of producing spherical selenium nanoparticles in the size range of 76-150 nm under ambient conditions. This is a first report on the production of nano-selenium assisted by an ionic liquid. The synthesized nanoparticles can be separated easily from the aqueous sol by a high-speed centrifuge machine, and can be re-dispersed in an aqueous medium. The synthesized selenium nanoparticles have been characterized by X-ray diffraction, energy dispersive X-ray analysis, differential scanning calorimetry and transmission electron microscopy techniques.     

富硒葡萄中硒限量标准的研究

生产富硒农产品,为缺硒地区居民提供天然补硒食品,近年来已成为我国保健食品的热点,但是过多地摄入硒对人体健康有害。目前我国缺少相关的硒含量标准,根据人体日常硒摄入量需求和水果中硒含量结合富硒葡萄种植的实验数据就福建省富硒葡萄硒含量标准提出建议。     

Accurate and precise measurement of selenium by instrumental neutron activation analysis

An accurate and precise measurement of selenium in Standard Reference Material (SRM) 3149, a primary calibration standard for the quantitative determination of selenium, has been accomplished by instrumental neutron activation analysis (INAA) in order to resolve a question arising during the certification process of the standard. Each limiting factor of the uncertainty in the activation analysis, including the sample preparation, irradiation, and γ-ray spectrometry steps, has been carefully monitored to minimize the uncertainty in the determined mass fraction. Neutron and γ-ray self-shielding within the elemental selenium INAA standards contributed most significantly to the uncertainty of the measurement. An empirical model compensating for neutron self-shielding and reducing the self-shielding uncertainty was successfully applied to these selenium standards. The mass fraction of selenium in the new lot of SRM 3149 was determined with a relative standard uncertainty of 0.6%.     

石墨烯-硒化物量子点复合物的制备与性能研究

利用表面包覆1层吡啶分子的量子点和化学还原性石墨烯通过π-π堆积的方式,制备了石墨烯-量子点(PbSe、ZnSe、CdSe)复合物。包覆在量子点外层的吡啶分子芳香环结构起到桥梁的作用,将石墨烯和量子点π-π堆积起来,同时延伸了石墨烯的共轭结构。通过XRD、UV-Vis、TEM、Raman等表征手段,考察了相应复合物的结构、形成机理与性质。所制石墨烯-量子点复合物能稳定分散于水或极性溶液中,使得此类石墨烯复合物在生物体内具有良好的应用前景。通过循环伏安法对制备的产物进行了电化学性能测试。根据循环伏安曲线,复合物CCG-ZnSe的电容较单纯的CCG、ZnSe有大幅提高。