纳米银导电油墨的制备研究与包装应用概论

纳米导电油墨具有独特的物理及化学性质,而导电填料则决定导电油墨的性能。概述了纳米导电油墨的组成、分类及特点,主要论述了纳米银的特性,相较于其他填料,纳米银具备良好的导电性、导热性、纳米光学性、高比表面积等特性,因而纳米银作为导电填料成为了制备导电油墨的首选;进一步阐述了纳米银的制备方法及纳米银导电油墨的配方设计及制备工艺,通过不同的研究分析了纳米银导电油墨性能的影响因素,以及纳米银导电油墨在不同包装应用的发展趋势,并对其应用研究提出了建议。     

软模板技术制备银的各向异性纳米粒子

纳米银的光学、电学和催化活性与粒子的粒径、形貌和结构之间存在着强烈的依赖关系,研究各向异性银纳米材料的形成具有重要意义.结合软模板技术在各向异性银纳米材料制备方面的研究成果,着重讨论了银纳米棒和纳米线的制备方法和形成机理,概述了树枝状纳米银、纳米银片(盘)、纳米银立方体和三棱柱的研究进展,指出利用软模板技术可合成各种形貌的纳米银粒子,并指出了此类材料在研究中存在的不足,展望了其发展趋势.     

AOT反胶束法制备纳米银的机理及应用

AOT反胶束体系既为制备纳米粒子提供了反应器,又控制了粒子尺寸分布,是制备贵金属银纳米粒子的最佳方法.阐述了AOT反胶束体系制备纳米银粒子的机理,综述了制备过程中浓度、连续相类型等对纳米银粒子粒径和形貌的影响,并介绍了当前该方法的应用进展,展望了今后的发展趋势.     

纳米Ag/PMMA复合薄膜的原位法制备及性能研究

采用原位法,以二甲基甲酰胺(DMF)为还原剂和溶剂,制备纳米Ag/PMMA复合薄膜.采用XRD、TEM、FT-IR、UV-Vis表征了纳米Ag/PMMA复合薄膜物相,纳米银的颗粒形貌,分析了纳米银与基体PMMA之间的相互作用机理,并对溶胶和薄膜的光学特性进行表征.结果表明,反应生成的为面心立方银单质,并且随着反应时间的...     

纳米银粉在水溶液中的分散及粒径表征

利用直流电弧等离子体蒸发冷凝法制备纳米银粉,采用X射线衍射分析对纳米银粉的结构进行表征,采用纳米激光粒度仪研究不同超声分散工艺与不同离子类型的分散剂聚乙烯吡咯烷酮、十六烷基三甲基溴化氨、十二烷基硫酸钠对纳米银粉在水溶液中分散性能的影响,获得纳米银粉的最佳分散工艺与激光粒径分布,对比研究纳米银粉的激光粒径与透射电镜统计的粒径的差异。结果表明:纳米银颗粒为立方晶系多晶体,颗粒的结晶性良好;以十六烷基三甲基溴化氨为分散剂的效果最理想,最佳超声波功率为600 W;当十六烷基三甲基溴化氨的质量浓度为0.5 g/L时,纳米银颗粒的分散稳定性较好;激光粒径反映的纳米颗粒的动态二次粒径略大于从透射电镜图像统计得到的粒径。     

纳米氧化高银的制备及抗菌性能

采用液相氧化沉淀法制备纳米氧化高银颗粒.以硝酸银为原料,氢氧化钠为沉淀剂,过硫酸钾为氧化剂,控制pH值为11,反应温度为80℃,在磁力搅拌器上反应30min,静置3h后,离心洗涤数次,70℃真空干燥3h,得到黑色纳米氧化高银颗粒.通过X射线衍射(XRD)、透射电子显微镜(TEM)对纳米氧化高银颗粒的形貌和结构进行表征;采用异养菌测试瓶法,用制备的氧化高银和粒径为30nm的纳米银对金黄色葡萄球菌进行抗菌性能测试.结果表明:制得的球形纳米颗粒粒径为10～30ntn;纳米氧化高银颗粒比纳米银具有更强的杀菌性能.     

多形貌纳米银粒子的制备工艺研究

随着电子元器件向微型化、精密化和柔性化等方向发展,金属导电填料纳米化成为电子封装用导电银浆发展的必然趋势。其中,多形貌纳米银粒子的制备成为该领域的研究热点。采用液相还原法,通过多种表面活性剂的添加调控纳米银晶粒的生长过程,制备出球状、片状、立方状等多种形貌的银纳米粒子,并揭示了它们的生长机理。结果表明,随着聚乙烯吡咯烷酮(PVP)浓度的增加,纳米银颗粒的分散性得到逐步优化,当PVP浓度为2mmol/L时,制备出平均粒径为20nm左右且分散性良好的球状银纳米粒子;柠檬酸钠和双氧水的添加能够诱导纳米银颗粒向片状结构转变,当柠檬酸钠浓度为20mmol/L,双氧水浓度为25mmol/L左右时,有大量片状银纳米粒子的形成;氯化钠(NaCl)能够诱导纳米银颗粒向立方体结构转变,当NaCl浓度为20mmol/L时能够得到形状规则的立方银纳米粒子。     

纳米材料

我国建成年产可达10吨以上的纳米银微粉生产线 我国科研人员日前研制出新一代抗菌产品,并建成一条年产可达10吨以上的纳米银微粉生产线,可年产700万平方米抗菌布,从而标志着我国纳米材料在医药抗感染领域的应用达到世界先进水平。 从“纳米技术产业化与投资高峰论坛”上获悉,清华大学企业集团控股的深圳清华源兴纳米公司成劝研制出了“防聚集纳米银抗菌微粉”,这种纳米银微粉经美国斯坦福大学、清华大学、北京大学扫描电子显微镜检测纳米银粒径在1到100纳米之间,其中大多数纳米银为25纳米左右,棕色,呈粉末状。     

纳米银制备研究进展

综述了纳米银的广泛应用及主要制备方法,论述了化学法制备各向异性银纳米材料的研究进展,探讨了银纳米粒子形貌与性能的关系,指出了银系纳米材料研究中存在的不足.详细综述了球形、线(棒)型、立方体形、三角形等其它各种形状银纳米粒子的制备工艺条件和形成机理,阐述了工艺条件对纳米银尺寸、形貌及存放稳定性的影响,比较了不同制备方法的优劣,并指出了银系纳米材料的发展趋势.     

纳米银液相可控制备的研究进展

纳米银(银纳米颗粒)是一类新兴的银基功能材料。近15年来,随着液相纳米制备技术的快速发展,纳米银的光学、电学性能以及广谱抗菌等生物活性得以深入地研究,并在光电以及生物医学领域获得了重要应用。大量的研究表明,纳米银的上述优异特性强烈依赖于其尺寸、形貌和结构。因此,纳米银的可控制备将是对其特性的合理调控及后续应用的前提。评述了基于液相的纳米银可控制备的研究进展:首先讨论了液相体系中纳米银的生长机制,之后介绍了主要的制备方法,包括直接化学还原法、种子介导生长法、模板法、光诱导法、微波辅助还原法等。在此基础上,根据颗粒的维度,将纳米银分为零维、一维和二维结构,对上述纳米银的代表性结构的可控制备方法及研究现状分别进行了评述。最后简述了纳米银液相可控制备的未来发展方向。     

Superhydrophobicity and surface enhanced Raman scattering activity of dendritic silver layers

Dendritic silver nanostructured surface has been prepared on copper substrate by a simple replacement reaction. It was observed that morphology of the silver surface became much rough with reaction time, from initial nanosized clusters to nanostructured dendrites. The silver surface modified with dodecanethiol showed great superhydrophobicity. It was also found that the dendritic silver nanostructured surface demonstrated highly sensitive surface enhanced Raman scattering (SERS) character. It is expected that the dendritic silver surface may be applied as molecular probe and biological sensing.     

Gas phase electrodeposition: a programmable multimaterial deposition method for combinatorial nanostructured device discovery

This article reports and applies a recently discovered programmable multimaterial deposition process to the formation and combinatorial improvement of 3D nanostructured devices. The gas-phase deposition process produces charged <5 nm particles of silver, tungsten, and platinum and uses externally biased electrodes to control the material flux and to turn deposition ON/OFF in selected domains. Domains host nanostructured dielectrics to define arrays of electrodynamic 10 × nanolenses to further control the flux to form <100 nm resolution deposits. The unique feature of the process is that material type, amount, and sequence can be altered from one domain to the next leading to different types of nanostructures including multimaterial bridges, interconnects, or nanowire arrays with 20 nm positional accuracy. These features enable combinatorial nanostructured materials and device discovery. As a first demonstration, we produce and identify in a combinatorial way 3D nanostructured electrode designs that improve light scattering, absorption, and minority carrier extraction of bulk heterojunction photovoltaic cells. Photovoltaic cells from domains with long and dense nanowire arrays improve the relative power conversion efficiency by 47% when compared to flat domains on the same substrate.     

Step-wise Ag thin film patterns fabricated by holographic lithography

A laser-induced thermo-elastic removal was used to pattern nanostructured silver thin films solution-deposited on the glass substrate. We show that sharp-edged patterns can be fabricated under an interference-generated gradual intensity profile. The etching behavior and the resulting pattern morphology were very sensitive to the cohesion of the film and its adhesion to the substrate, being both modified by the post-deposition annealing process. The fabrication of step-wise one-dimensional (1D) and 2D patterns at the micrometer scales is demonstrated by holographic lithography using an Nd:YAG pulsed laser, along with a discussion on the effect of film cohesion and adhesion.     

PET基纳米Ag薄膜形貌与导电及电磁屏蔽性能的分形表征

采用磁控溅射法在PET非织造布上制备了不同厚度的纳米结构Ag薄膜,用高度相关函数法对薄膜的原子力显微镜(AFM)图像进行分形维计算,用AFM分析不同厚度纳米结构Ag薄膜形貌及粒径的变化;用网络测试仪测试了不同厚度样品的电磁屏蔽效能。结果表明,随着薄膜厚度的增加,薄膜表面质量提高,分形维增大;电磁屏蔽效能也随分形维的增大而增加。可以认为,分形维能有效地表征薄膜的表面形貌,分形维与导电及屏蔽效能存在明显的对应关系,并可以用分形维优化磁控溅射的工艺条件。     

Aluminum nanostructured films as substrates for enhanced fluorescence in the ultraviolet-blue spectral region

Particulate aluminum films of varied thicknesses were deposited on quartz substrates by thermal evaporation. These nanostructured substrates were characterized by scanning electron microscopy (SEM). With the increase of aluminum thickness, the films progress from articulate toward smooth surfaces as observed by SEM images. To date, metal-enhanced fluorescence (MEF) has primarily been observed in the visible - NIR wavelength region using silver or gold island films or roughened surfaces. We now show that fluorescence could also be enhanced in the ultraviolet-blue region of the spectrum using nanostructured aluminum films. Two probes, one in the ultraviolet and another one in the blue spectral region, have been chosen for the present study. We observed increased emission, decrease in fluorescence lifetime, and increase in photostability of a DNA base analogue 2-aminopurine and a coumarin derivative (7-HC) in 10-nm spin-casted poly(vinyl alcohol) film on Al nanostructured surfaces. The fluorescence enhancement factor depends on the thickness of the Al films as the size of the nanostructures formed varies with Al thickness. Both probes showed increased photostability near aluminum nanostructured substrates, which is consistent with the shorter lifetime. Our preliminary studies indicate that Al nanostructured substrates can potentially find widespread use in MEF applications particularly in the UV-blue spectral regime. Furthermore, these Al nanostructured substrates are very stable in buffers that contain chloride salts compared to usual silver colloid-based substrates for MEF, thus furthering the usefulness of these Al-based substrates in many biological assays where high concentration of salts are required. Finite-Difference Time-Domain calculations were also employed to study the enhanced near-fields induced around aluminum nanoparticles by a radiating fluorophore, and the effect of such enhanced fields on the fluorescence enhancement observed was discussed.     

Surface-enhanced fluorescence from silver fractallike nanostructures decorated with silver nanoparticles

Fluorescence emission of fluorophore molecules in the close vicinity of a nanostructured metal surface can be enhanced through a local electromagnetic field with the help of surface plasmon resonance. The fluorescence enhancement effect is very sensitive to the topography and dielectric property of the metal substrate. In the current work, metal substrates with complex structures, which are made of silver fractallike structures and nanoparticles (NPs), are prepared through electrochemical reduction followed by physical deposition. The surface-enhanced fluorescence of Rhodamine 6G monolayer molecules deposited on the prepared complex substrates are investigated with the laser spectroscopic technique. The experimental results show that the fractallike structure decorated with silver NPs presents stronger fluorescence enhancement, compared with silver NPs or pure silver fractallike structures.     

Deterministic Assembly of Single Sub-20 nm Functional Nanoparticles Using a Thermally Modified Template with a Scanning Nanoprobe

A deterministic assembly technique for single sub-20 nm functional nanoparticles is developed based on nanostructured templates fabricated by hot scanning nanoprobes. With this technique, single nanoparticles including quantum dots, polystyrene fluorescent nanobeads, and gold nanoparticles are successfully assembled into 2D arrays with high yields. Experimental and theoretical analyses show that the key for the high yields is the hot-probe-based template fabrication technique, which creates geometrical nanotraps and modifies their surface energy simultaneously. In addition to single nanoparticle patterning, further experiments demonstrate that this technique is also capable of building complex nanostructures, such as nanoparticle clusters with well-defined shapes and heterogeneously integrated nanostructures consisting of quantum dots and silver nanowires. It opens the door to many important applications.     

Nanostructured electronic and magnetic materials

Research and development in nanostructured materials is one of the most intensely studied areas in science. As a result of concerted R & D efforts, nanostructured electronic and magnetic materials have achieved commercial success. Specific examples of novel industrially important nanostructured electronic and magnetic materials are provided. Advantages of nanocrystalline magnetic materials in the context of both materials and devices are discussed. Several high technology examples of the use of nanostructured magnetic materials are presented. Methods of processing nanostructured materials are described and the examples of sol gel, rapid solidification and powder injection moulding as potential processing methods for making nanostructured materials are outlined. Some opportunities and challenges are discussed.     

Silver‐Quantum‐Dot‐Modified MoO3 and MnO2 Paper‐Like Freestanding Films for Flexible Solid‐State Asymmetric Supercapacitors

Free‐standing paper‐like thin‐film electrodes have great potential to boost next‐generation power sources with highly flexible, ultrathin, and lightweight requirements. In this work, silver‐quantum‐dot‐ (2–5 nm) modified transition metal oxide (including MoO₃ and MnO₂) paper‐like electrodes are developed for energy storage applications. Benefitting from the ohmic contact at the interfaces between silver quantum dots and MoO₃ nanobelts (or MnO₂ nanowires) and the binder‐free nature and 0D/1D/2D nanostructured 3D network of the fabricated electrodes, substantial improvements on the electrical conductivity, efficient ionic diffusion, and areal capacitances of the hybrid nanostructure electrodes are observed. With this proposed strategy, the constructed asymmetric supercapacitors, with Ag quantum dots/MoO₃ “paper” as anode, Ag quantum dots/MnO₂ “paper” as cathode, and neutral Na₂SO₄/polyvinyl alcohol hydrogel as electrolyte, exhibit significantly enhanced energy and power densities in comparison with those of the supercapacitors without modification of Ag quantum dots on electrodes; present excellent cycling stability at different current densities and good flexibility under various bending states; offer possibilities as high‐performance power sources with low cost, high safety, and environmental friendly properties.     

Plasma reduction of silver compounds for fabrication of surface-enhanced Raman scattering substrates

Several silver compounds were reduced by low-pressure air plasma to produce porous nanostructured surfaces as surface-enhanced Raman scattering (SERS) substrates. This method is advantageous because substrates are easy to prepare and the silver metal surface is inherently clean without spectroscopic background. Silver compounds were melted into 1-2 mm slugs on quartz slides and plasma treated for different lengths of time. Silver chloride was found to be the best compound to make reproducible and stable SERS substrates. SERS activity of the substrates was tested using L-tryptophan, 4-mercaptobenzoic acid, and adenine.