电化学沉积金属银的二维枝晶生长及其结构

用电化学沉积方法,在液面有机单分子层诱导下生长出二维银膜。当电极电位由高向低快速转换时,银膜边界发生形态转变,生长出大量枝晶,尺度为几十微米,旁枝与主枝夹角约为60°,且具有明显的分形自相似结构。     

超声法制备PbS纳米晶

超声波辐射下,以硝酸铅、硫代乙酰胺为原料制备了PbS纳米晶,用TEM和XRD研究了聚乙二醇用量和反应时间对PbS纳米晶的影响。结果表明,超声波能抑制颗粒团聚;聚乙二醇具有良好的分散性和一维导向性。PbS纳米晶粒径较细、纳米棒长度为2μm。     

微波液相沉淀法制备CeO2纳米晶

以硝酸铈为原料,碳酸氢铵为沉淀剂,用微波加热的方法制备了纳米CeO2超细粉体,用X射线衍射法和透射电子显微镜等检测手段进行表征,结果表明,微波法制备样品的平均晶粒度为8nm,而传统加热法则为16nm,反应时间由60分钟缩短为5分钟,并提高了颗粒的分散性.     

BaTiO3纳米晶的制备和结构

ＢａＴｉＯ_３纳米晶的制备和结构方佑龄，赵文宽，邹化民，王仁卉（武汉大学化学系，武汉大学物理系，武汉，４３００７２）关键词钛酸钡纳米晶，过氧化物，制备，结构ＢａＴｉＯ３具有高介电常数及优异的铁电、压电性能，是一种重要的电子陶瓷材料，因此，对其纳米晶的?..     

特殊形貌CdSe纳米晶的制备

CdSe纳米晶是II-VI族半导体中研究最多的材料之一,由于其发射波长随纳米晶的尺寸而改变,从而可以覆盖从绿到红的宽光谱范围,因此CdSe纳米晶可以应用于生物标记和荧光显示等领域,各种制备CdSe纳米晶的方法也应运而生。因制备方法的不同,所得CdSe纳米晶的粒径、相结构及形貌也不同,进而影响CdSe纳米晶的性质。本文归纳了7种典型的制备一些特殊形貌的CdSe纳米晶的最新方法,并对各种方法的优缺点作了简单评价。最后,对这一领域未来的研究和发展方向作了展望。     

硒化银纳米枝晶的合成与表征(英)

Silver selenide nanodendrites were synthesized by the reaction of AgNO₃ and sodium selenosulfate in the presence of cetyltrimethyl ammonium bromide (CTAB). The as-synthesized sivler selenide samples were characterized by XRD, TEM and SAED. The results showed that Ag₂Se nanodendrites were of single crystalline with diameters ranging from 60～150 nm.     

聚苯乙烯接枝淀粉纳米晶的制备

通过淀粉纳米晶与苯乙烯乳液聚合的方法制备了聚苯乙烯接枝淀粉纳米晶并用FTIR和1HNMR进行了表征;制备了不同接枝聚苯乙烯单体与淀粉纳米晶的物质的量之比(MS)的聚苯乙烯接枝淀粉纳米晶,在苯乙烯单体和淀粉纳米晶摩尔比(M/SN)为2,反应时间为5～12h条件下,所得MS为0.15～0.67.X-射线衍射结果表明,接枝聚苯乙烯几乎不会改变淀粉纳米晶的晶型,但结晶度随着MS的增加而下降.     

溶剂热法制备银纳米晶

以聚乙烯吡咯烷酮(PVP)作为表面活性剂,利用乙二醇溶剂热法成功制备了银纳米颗粒;利用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)分析了样品的形貌和晶体结构,并考察了溶剂组成等因素对银纳米颗粒形貌的影响.研究结果表明所得银纳米晶粒径均一,直径约为90nm;增大PVP的加入量会降低产物的粒径,溶剂中水的引入会影响银纳米晶的形貌.     

双金属Ag-Cu枝晶的制备及应用

通过铜箔基体上电沉积泡沫铜结合伽尔瓦尼置换反应制备出了银-铜(Ag-Cu)纳米枝晶, 利用X射线衍射(XRD)和场发射扫描电子显微镜(FE-SEM)对枝晶的成分及形貌进行研究发现, 随着沉积过电位的增加, 铜的前驱体形貌由棒状到枝晶状, 最后发展为泡沫状, 但泡沫状的前驱体制备的Ag-Cu 枝晶却是最规整和致密的. 另外, 银离子的浓度也会影响枝晶的形貌, 一定范围内浓度的增加有利于枝晶的形成. 通过线性扫描伏安和电流-时间曲线对制备的Ag-Cu 枝晶催化性能进行表征, 在电解质溶液中, -0.25 V(相对于饱和甘汞电极(SCE))时有一个明显的双氧水(H₂O₂)还原峰, 这意味着Ag-Cu枝晶对H₂O₂的电还原具有较好的催化活性, 当该电极被用于双氧水传感器时, 电流响应快, 能在3 s 内达到稳态电流, 线性测量范围为0.1-12 mmol·L^-1, 灵敏度可以达到330.36 μA·(mmol·L^-1)^-1·cm^-2, 这点对于提高传感器的准确性非常重要.     

阴极腐蚀合金丝制备团聚型PtIr纳米粒子以及Ir枝晶

采用方波电势法(SWP)对PtIr合金丝进行阴极腐蚀制备了团聚型的PtIr合金纳米粒子(PtIr-NPs),制备过程中无需金属离子前驱体和还原剂的参与,反应条件温和.采用扫描电镜(SEM)、能谱仪(EDS)、高分辨透射电镜(HR-TEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)对产物进行了表征.与Pt纳米粒子...     

单体摩尔比对PbSe纳米粒子生长的影响

本文研究了不同温度下,Se单体与Pb单体的不同摩尔比对PbSe纳米粒子晶体成核和晶体生长的影响。实验显示,摩尔比较大,Se单体比较多时,PbSe成核比较容易但是PbSe纳米粒子的生长比较慢。主要有两方面原因,一方面是因为Se单体的活度比较大,另一方面是由于PbSe纳米粒子的外壳是Pb壳的粒子结构。     

纳米酞菁氧钛(TiOPc)的制备及光敏性能

纳米酞菁氧钛(TiOPc)的制备及光敏性能;有机光导材料     

Electron Paramagnetic Resonance Study of PbSe,PbTe, and PbTe:In Semiconductors Obtained by the Pulsed Laser Deposition Method

The magnetic properties of lead selenide (PbSe) and indium-doped lead telluride (PbTe:In) composites have been studied by using the electron paramagnetic resonance (EPR) technique. The samples were obtained by using the pulsed laser deposition method (PLD). Temperature dependences of the EPR spectra were obtained. The analysis of the temperature dependencies of the integral intensity of the EPR spectra was performed using the Curie–Weiss law. In these materials, the paramagnetic centers of Pb¹⁺ and Pb³⁺ ions were identified. The results are discussed.     

纳米级PbCO3制备方法的改进

对沉淀法制备的PbCO3 结构和形貌的表征发现PbCO3 晶体生长速度很快 ,沉淀法很难制备纳米级PbCO3 。采用 80 0 0r/min高速条件下的沉淀法 ,制备了纳米级PbCO3 。同时对原料和反应物浓度影响的实验表明 ,Pb(CH3 COO) 2 ·3H2 O取代Pb(NO3 ) 2 时 ,所制备PbCO3 的粒度分布集中 ,粒子尺寸为 10 30nm ,并且粒子粒径随着Pb(CH3 COO) 2 ·3H2 O浓度的增大而减小     

Aspect ratio dependent air stability of PbSe nanorods and photovoltaic applications

Development of unique strategies to overcome Shockley–Queisser (SQ) limit in solar cells has gained a great deal of interest. Multiple exciton generation (MEG) process has been considered as one of the best approaches to the SQ limitation. In this respect, PbSe quantum dots (QDs) and nanorods (NRs) have been regarded as promising solar energy harvesting materials owing to their noticeable MEG yields. Although air stability has been regarded as one of the main disadvantage of PbSe QDs, no study has pointed out to the air sensitivity of PbSe NRs yet. Here, we reveal the effect of aspect ratio on air sensitivity and optical properties of PbSe NRs and discover that NRs with higher aspect ratios are more air stable, attributed to the reduced density of NR ends with air sensitive {100} facets. Furthermore, a band offset was created by utilization of tetrabutylammonium iodide and 1,2-ethanedithiol ligands in cell designs. We found that solar cells based on pristine PbSe NRs are limited by low open circuit voltages due to leakage current pathways. On the other hand, modified cells comprising light absorbing layers prepared by blending NRs and QDs and hole transporting QD layer exhibit a 10-fold improvement in solar cell efficiency.     

纳米钴蓝颜料的微乳法制备及其表征

纳米粒子;微乳液;量子尺寸效应;纳米钴蓝颜料的微乳法制备及其表征     

PbSe纳米棒的模板合成及其性质

在表面活性剂十六烷基三甲基溴化铵(CTAB)存在下,利用N2 H4·H2O还原H2SeO3合成出单质硒纳米管,然后以硒纳米管为模板,与Pb(NO3):和N2 H4·H2O在常压低温下反应,制备了PKSe纳米棒.采用电子透射电镜、X射线衍射等方法对产物进行了表征.探讨了PbSe纳米棒的形成机理和制备反应的影响因素.测定了产物的荧光性质,并利用电位扫描伏安法研究了所得PbSe纳米棒的电化学性质.结果表明,所得产物在碱性介质中电化学活性较高,在循环伏安曲线上出现明显的氧化峰和还原峰.     

Electrodeposition and characterization of PbSe films on indium tin oxide glass substrates

Electrodeposition of lead selenide (PbSe) thin films on indium tin oxide (ITO) covered glass is described. While disodium salt of ethylenediaminetetraaceticacid was used to complex the lead ions, well crystallized, nearly stoichiometric and mirror-like PbSe films were deposited on ITO glass in potentiostatic mode using aqueous acidic electrolyte containing Pb and Se precursors at different bath temperature. The improvement of crystallinity of the PbSe films deposited at different temperature was studied using X-ray diffraction and Raman scattering. The morphology and composition of the films were characterized by scanning electron microscopy and energy disperse analysis by X-ray, respectively. The optical property of the film was studied by optical measurement techniques.     

A Facile Phosphine‐Free Method for Synthesizing PbSe Nanocrystals with Strong Optical Limiting Effects

PbSe semiconductor nanocrystals (NCs) have attracted ever‐growing interest owing to both their fundamental physics and potential applications in a diverse range of fields such as optoelectronic devices and nonlinear optics. The current fabrication strategy for colloidal PbSe NCs, however, frequently involves acutely toxic reagents and tedious reaction procedures, and is plagued by products with poorly controlled size and morphology. Herein, we report a facile, low‐cost, and phosphine‐free method for synthesizing PbSe NCs, which provides highly uniform NCs with tunable mid‐IR absorption, and they are promising for bio‐related applications. These high quality NCs were obtained by the reaction of elemental Se and PbCl₂ in oleylamine as both the ligand and reaction medium. The high flexibility and reproducibility of the method reported in this study allows us to synthesize monodispersed PbSe NCs with well‐controlled size and morphology. In addition, these products show strong optical limiting effects, and thus hold potential for developing nonlinear optical devices.     

液相法制备纳米氧化锡防团聚方法综述

针对液相法制备纳米氧化锡颗粒团聚的问题,以溶胶-凝胶法为例,介绍了防团聚的几种措施:加入表面活性剂,有机溶剂洗涤,共沸蒸馏及冷冻干燥等.这几种方法虽可以制备出粒径较小,均匀,分散性好的粒子,但也各有优缺点:反应时加入表面活性剂,容易引入杂质;有机溶剂洗涤廉价而便利,但是存在洗涤凝胶滤饼时溶剂漏滤的问题;而共沸蒸馏需要特殊的减压装置,比较看来,利用有机溶剂洗涤是一种相对方便的办法.