Name: synthesis, characterization, and functionalization of hybrid au/cds and au/zns core/shell nanoparticles
Uploaded: 2016-03-02T13:00:00.000+00:00
Duration: 8 min 19 s
Description: Watch this Scientific Journal Video about Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles at JoVE.com

这种材料是基于CHE下由美国国家科学基金会资助的工作 - 1352507。

1.金纳米粒子的合成<ol><li>权衡金盐在手套箱并在容量瓶用水稀释之前添加到预先用王水清洗的小瓶。在100毫升水中制备1毫三氯化金三水合物（393.83克/摩尔）为金储备溶液。 </li><li>称出3.2克固体CTAC（320克/摩尔）和热，在25毫升的水，至约60℃溶解。冷却至室温，并稀释用至50ml与水的混合物在容量瓶中以制备0.2M的十六烷基三甲基氯化铵（CTAC）。 </li><li>混合加入20ml 1mM的金溶液和20毫升的0.2的圆底的油浴设定为60℃，沸点烧瓶和地点内中号CTAC溶液。允许混合10分钟。 </li><li> 1.7毫克添加（1:1摩尔比）的固体硼烷叔丁基胺（86.97克/摩尔）的金/ CTAC溶液，并让搅拌30分钟。 注:解决方案应该变成深红色。所得溶液具有金颗粒concentrati上约5微米的，并且可以在一个时间被存储数月或立即用于反应的下一个阶段中使用。 </li></ol> 2.镀层银<ol><li>使用精确试剂量涂布纳米颗粒采用了银色外壳。外壳将提供对半导体壳的尺寸和形状的模板。精确试剂的量也将有助于防止银颗粒的成核作用。 </li><li>首先计算芯的体积，以cm 3，并使用金的密度转换为质量每粒子。例如，为了计算芯体积，假定直径为15纳米的球形纳米粒子，得到纳米1767.15 3的体积，然后将转换为cm 3（1.77×10 -18厘米3）。由金（19.3 毫升 ）的密度乘以体积来计算每个粒子的质量（3.41×10 17）。 <ol><li>用10毫升5.3μM的金纳米颗粒溶液，对5.30×10 -8摩尔文章存在。由摩尔质量乘以给计算在溶液（1.04×10 -5 G）本金的质量。分割的金质量在由每个粒子质量的解决方案，以找到本（3.06×10 11）的金颗粒的数量。 </li><li>计算用5纳米壳厚纳米粒子的体积，以cm 3（8.18×10 18厘米3），并从核心纳米颗粒（1.77×10 -18厘米3），以确定壳体积的体积减去该（6.41 ×10 -18）。由金颗粒的数量和银的密度（2.33×10 -4）乘以转换此体积与银的质量。在1-10纳米范围内壳的厚度将在本研究中使用。 </li><li>转换银的质量，以所需要的5纳米壳半径（2.33×10 -4）的银摩尔。从这个值，计算为4.0毫摩尔的硝酸银540微升）溶液所需F中的体积或金的量在起始溶液（10毫升）中利用。 </li></ol></li><li>制备4.0毫米的AgNO 3（169.87克/摩尔）在5毫升水中的溶液。在70℃的油浴中，将10 ml储备金纳米颗粒与抗坏血酸做出的20mM溶液。 </li><li>添加银溶液逐滴于黄金和抗坏血酸溶液，并允许反应搅拌2小时。 注:反应会变成浅橙色（稀释剂壳），以深橙色（厚壳）在反应过程。 </li><li>离心纳米粒子在21130 XG 10分钟，再分散到干净的水。倒出从丸状纳米粒子的上清液中去除裸金纳米粒子或可能已形成的银纳米颗粒的帮助。 </li></ol> 3.壳牌硫化银转换<ol><li> 1摩尔比在实验的前一阶段所用的银:在200权衡元素硫。对于10毫升Au / Ag核壳颗粒和5纳米壳，溶解3毫升油胺和1.5ml油酸成10毫升甲苯。 <ol><li>浓缩银胶体，通过离心21130×g离心10分钟，并在1毫升水中分散。 注意:此步骤有助于在形成银壳的提高提取效率从水层到有机层中。 </li></ol></li><li>添加胶体，搅拌1小时下逐滴向硫溶液。 注:该解决方案将变成深蓝色（薄弹），紫色（厚壳）作为硫化去完成。 </li><li>离心在4000 xg离心胶体溶液10分钟，在反应搅拌2小时，从溶液中除去水和未反应的硫后。如有必要，再分散的纳米颗粒转化为清洁的甲苯与超声。 <ol><li>超声处理在槽式声波处理器进行30秒至1分钟的纳米粒子以分散到甲苯中。 注意:过量的油胺或油酸酸可以从溶液中析出，并且可以此步骤通过倾析从该白色固体的溶液后除去。 </li></ol></li></ol> 4.阳离子交换<ol><li>由金属硝酸盐溶于1ml甲醇使金属前驱体，使镉的0.2M的溶液（NO 3）或Zn（NO 3）。 注意:一0.8M的溶液可被用于厚壳以降低在溶液的甲醇的量。 <ol><li>混合在一个1银硫化物纳米壳的金属溶液:用银摩尔比为1:1。热至50℃镉壳和65℃下在氮气氛下的锌的炮弹。 </li></ol></li><li>摩尔比为1:1到金属前体:在一个500添加三叔丁基膦。反应时间是镉2小时和20小时为锌。 </li><li>通过离心以除去可能已形成的任何分离的CdS或ZnS纳米粒子净化在21130×g离心10分钟。分散沉淀的nanoparticles到一个干净的非极性溶剂如己烷，甲苯或氯仿。 </li></ol> 5.配体交换从油胺<ol><li>混合用1.5倍体积比的乙醇的甲苯在离心管中的纳米颗粒溶液到胶体溶液。离心机在4000×g离心10分钟以沉淀所述纳米颗粒。 </li><li>用乙醇和离心再次收集固体颗粒洗纳米颗粒。 注:颗粒可以存储在该阶段，但除去乙醇，需要防止聚集。 </li><li>结合配体与通过上壳未结合的阳离子位点的亲核结合基团在表面上。 11-巯基十一酸和3,4-二氨基苯甲酸是其离开纳米颗粒水溶性适当的分子。 <ol><li>分散纳米颗粒引入该配位体溶液中大量过量，比天然油分子高约10倍的浓度。在室温下搅拌澳颗粒vernight以允许任何残余的油分子的位移。 </li><li>离心在4000 xg离心该溶液10分钟。洗用甲醇和离心沉淀的颗粒在4000 xg离心10分钟一次，以收集固体纳米颗粒。 </li></ol></li></ol>

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Authors have nothing to disclose

金纳米粒子为了保证高质量的芯壳纳米颗粒，金纳米颗粒的单分散样品必须首先被合成为模板。28,29,30我们修改了金纳米粒子的合成，以产生长链叔胺封端的纳米颗粒代替油胺封端的纳米粒子。油胺封端的纳米颗粒显示出相当窄的等离子体共振，表示单分散尺寸范围，但​​使用叔丁基胺通过还原合成的颗粒，并在生产长链叔胺封端的纳米粒子的存在下显示出显著更?...

金和银纳米粒子具有在可见激励用于在各种应用，包括光电子，1光伏，2催化，3化学/生物传感，4生物成像，5和光动力学治疗的未来的技术进步的潜力。 图6中 ，表面的电子可摆动到形成已知为局域型表面等离子体共振（SPR），其可以被用于集中入射辐射在可见光谱的共振。最近，贵金属纳米颗粒已合并半导体或磁性纳米颗粒，以产生混合的纳米颗粒具有增强和可调功能。-7,8-最近的文献，如由欧阳等人 9或Chen等 10所进行的研究，已经显示出了可能性为这些颗粒的合成，但在混合物种的均匀性仅有限的控制是可能的，因为金纳米颗粒尺寸分布，并通过在生长的每个阶段加上物理​​特征缺乏光学表征的配混。 Zamkov 等显示相似的均匀性在外壳形成，但只有一个壳厚度利用具有不同的核心的尺寸，一些炮弹不被所述纳米颗粒周围完全形成。为了有效地利用这些纳米颗粒中，精确的光学响应必须是已知的，并表征为多种壳的厚度。在壳厚度更高的精度可以通过使用单分散性，水性金颗粒作为模板来完成，从而导致在最终的混合物种更高的控制。芯和壳之间的相互作用可能会显示的吸收或发射率增强有限由于半导体材料的少量的接近金芯。而不是在外壳和金颗粒中发现的半导体之间的相互作用，所述壳可以是使用-d作为间隔物，以限制距离的外部发色团之间11这将允许在等离子体而之间的空间间隔更高的控制，否定与金属表面直接接触的后果。 表面等离子体共振和在发色团产生的激子之间的电子相互作用的程度，直接相关于金属和半导体物种之间的表面环境强度的相互作用的距离，和12中。当种类通过的距离隔开大于25纳米，两个电子状态保持未被干扰和光学响应保持不变。13强耦合机制是占优时颗粒具有更紧密接触，并可能导致在通过非辐射率增强或福雷斯特共振能量转移任何激发能量的猝灭（ FRET）14,15操作的耦合强度，通过调整日发色和金属纳米粒子两地电子间距，可导致积极的效果为好。该纳米颗粒的消光系数可以是数量级比大多数发色团时，使纳米粒子更有效地集中入射光。利用纳米颗粒的提高激励效率可导致生色较高激发速率。激励偶极子12耦合还可以增加其中可导致量子产量增加，如果非辐射率不受影响的发色团的发射速率。12，这些效应可能导致太阳能电池或具有增加的吸收膜，和光伏效率，由黄金和容易从半导体层的电荷的提取的增加的吸收截面由于局部表面状态的存在促进。12,16这研究也将提供关于等离子体作为AF耦合强度的有用信息距离恩膏。 局部表面等离子体振子已广泛在传感17和检测18应用中，由于等离子体共振的局部环境的敏感性。 Cronin 等人，显示出的TiO 2膜的催化效率可以与另外的金纳米颗粒得到改善。模拟表明，该增加的活性是由于在等离子体电场的耦合与在TiO 2，其随后增加激子生成速率生成激子。19 Schmuttenmaer对等人，表明染料敏（DSSC）的效率的太阳能电池可以与在Au / SiO 2的/ TiO 2的聚集体的结合得以改善。聚集体通过创造宽局部表面等离子体模式，这增加在更宽的频率范围内的光吸收的增强吸收。20在其它文献中，Li等人观察通过一个单一的CdSe /硫化锌量子点的直接耦合和单金纳米颗粒中观察到的荧光寿命ð显著减少以及距离依赖性增强在稳定状态下的荧光强度。21为了借此电浆增强充分利用，有一个需要用于与两个物种之间的一组距离物理耦合。 混合纳米颗粒的合成 Jiatiao。 等 ，以便产生均匀的和可调谐壳厚度通过阳离子交换所描述的方法来涂覆半导体材料上的金纳米颗粒。炮弹是在均匀厚度，但黄金模板不是很单分散的。这将改变半导体金比例由颗粒与颗粒，因此耦合强度。9对这些核壳纳米粒子的光学特性的深入研究已进行，为了发展一个生殖ucible合成方法。以前的方法依赖于基于有机的纳米粒子的合成，其可以产生具有广泛的等离子共振的样品由于在金纳米颗粒尺寸的不均匀性。金纳米颗粒的改性水性合成可用于长时间提供具有稳定重现性的单分散金纳米颗粒的模板。含水表面活性剂十六烷基三甲基氯化铵形成的纳米颗粒表面上的双层，由于附近的十六烷基三甲基氯化铵的分子的长碳链之间的相互作用。22这种厚的表面层需要仔细洗涤，以除去过量的表面活性剂，并允许访问所述纳米颗粒表面的，但可提供对纳米颗粒尺寸和形状更高的控制。23将水加入银壳可以高精度导致壳的厚度和光学特性之间的更亲密关系来控制。23经由抗坏血酸交流较慢还原标识被用来在金表面上沉积银，需要添加银盐是为了防止在溶液中形成纳米银的非常精确的。第三步骤需要被添加到有机相中的大量过量的硫和必须发生含水纳米颗粒的相转移。通过加入油胺作为有机封端剂和油酸，其可以同时作为封端剂，并在纳米颗粒，均匀的相转移助剂起作用，无定形硫化银壳可以在纳米粒子周围形成。9,24的浓度这些分子必须足够高以防止纳米粒子的聚集在该步骤中，但是过多的过量可以使纯化困难。在三正丁基膦和金属硝酸盐（镉，锌或铅）的存在下，无定形硫化物壳的内部的阳离子交换可以进行。反应温度必须修改为金属9的不同重新激活和任何过量硫必须被消除，以降低个体的量子点的形成。合成的每一步对应于纳米颗粒的表面环境的变化，因此，在等离子体的变化应观察由于等离子体频率的周围电介质场的依赖程度。光吸收如透射电子显微镜（TEM）表征的功能的平行研究用于表征纳米颗粒。该合成方法为我们提供了良好的控制，均匀的样品，提供从显微镜和能谱数据较好的相关性。 与荧光团耦合施加等离子体激元金属表面和荧光团之间的电介质间隔层可以帮助减少由于创建的激子的非辐射能量转移到金属损失。这个间隔层也有助于在荧光团和之间的距离的依赖性的研究在金属表面上等离子体共振。我们建议使用混合纳米粒子作为我们的介质隔离层的半导体外壳。壳的厚度可以被调谐以纳米精度厚度范围为2nm至20nm允许进行精确的距离的相关性的实验。外壳也可以用镉，铅或锌阳离子和S，Se和Te的阴离子调谐，允许对不仅距离，而且介电常数，电子带结构和甚至晶格参数的控制。

<table><tbody><tr><td>MilliQ Water</td><td>Millipore</td><td>Millipore water purification system</td><td>water with 18 M&amp;#937; resistivity was utilized in all experiments</td></tr><tr><td>Gold(II) chloride trihydrate</td><td>Sigma Aldrich</td><td>520918</td><td>used as gold precursor for nanoparticle synthesis</td></tr><tr><td>Cetyl trimethyl ammonium chloride (CTAC)</td><td>TCI America</td><td>H0082</td><td>used as surfactant for gold nanoparticles</td></tr><tr><td>Borane tert butyl amine</td><td>Sigma Aldrich</td><td>180211</td><td>used as reducing agent for gold nanoparticles</td></tr><tr><td>Silver nitrate</td><td>Sigma Aldrich</td><td>204390</td><td>used as silver source for shell application</td></tr><tr><td>Ascorbic acid</td><td>Sigma Aldrich</td><td>A0278</td><td>used as reducing agent for silver shell application</td></tr><tr><td>Sulfur powder</td><td>Acros</td><td>199930500</td><td>used as sulfur source for silver sulfide shell conversion</td></tr><tr><td>Oleylamine</td><td>Sigma Aldrich</td><td>O7805</td><td>used as surfactant for silver sulfide shell conversion</td></tr><tr><td>Oleylamine</td><td>Sigma Aldrich</td><td>364525</td><td>used as surfactant for silver sulfide shell conversion</td></tr><tr><td>cadmium nitrate tetrahydrate</td><td>Sigma Aldrich</td><td>642405</td><td>used as cadmium source for cation exchange</td></tr><tr><td>zinc nitrate hexahydrate</td><td>Fisher Scientific</td><td>Z45</td><td>used as zinc source for cation exchange</td></tr><tr><td>11-Mercaptoundecanoic acid</td><td>Sigma Aldrich</td><td>450561</td><td>used as water soluable ligand during ligand exchange</td></tr><tr><td>3,4-diaminobenzoic acid</td><td>Sigma Aldrich</td><td>D12600</td><td>used as water soluable ligand during ligand exchange</td></tr><tr><td>UV-Vis absorption spectrophotometer</td><td>Cary</td><td>50 Bio</td><td>used to monitor absorption spectrum of colloidal solutions</td></tr><tr><td>JEOL TEM 2100</td><td>JEOL</td><td>2100</td><td>used to analyze size of synthesized nanoparticles. TEM grids were purchased from tedpella</td></tr><tr><td>FTIR spectrophotometer</td><td>Perkin Elmer</td><td>Spec 100</td><td>used to monitor chemical compostion of nanoparticle surface after ligand exchange.&amp;nbsp;</td></tr></tbody></table>

synthesis, characterization, and functionalization of hybrid au/cds and au/zns core/shell nanoparticles

电浆纳米颗粒用于光收集应用一个有吸引力的材料，由于其容易改性的表面，高表面积和大消光系数，可在整个可见光谱进行调谐。研究光学跃迁的电浆增强已成为流行，由于改变的可能性，并在某些情况下改善附近发色团的光吸收或发射特性，如分子染料或量子点。该等离子体可以耦具有发色团的激发偶极子的电场，扰动涉及的过渡，并导致增加的吸收和发射率的电子态。这些增强也可以在通过能量转移机制近距离否定，使得这两个物种临界的空间布置。最终，增强在电浆太阳能电池的光收集效率可能导致较薄的，因此，成本较低的设备。该developm混合核/壳颗粒耳鼻喉科可以提供一个解决这个问题。增加了一个金纳米粒子和发色团之间的电介质间隔件的是所提出的方法，以控制激子等离子体耦合强度，并由此平衡与电浆收益损失。对于黄金涂层的详细过程与提出硫化镉和硫化锌半导体​​纳米粒子弹。纳米粒子显示具有核心金颗粒和贝壳类，允许更准确的调查外发色团的等离子增强这两个尺寸控制高均匀性。

金纳米颗粒有三个不同的表面活性剂的归一化的吸收光谱示于图1中 。所用的表面活性剂是油胺，十四烷基三甲基氯化铵（TTAC），和十六trimetyl氯化铵。 CTAC和TTAC的表面活性剂显示出更窄​​的等离子共振吸收带。 还原剂的量不仅影响FWHM但所得纳米颗粒溶液的峰值位置。 图2的调查显示了峰与还原剂?...

Watch this Scientific Journal Video about Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles at JoVE.com

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

合成，表征和混合金/硫化镉和Au / ZnS核/壳纳米颗粒功能化

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

synthesis-characterization-functionalization-hybrid-aucds-auzns

Research

JoVE Journal

Chemistry

18.2K 次观看.  University of North Carolina at Charlotte. The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

视频: Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded synthesis strategy is used in which spherical seeds of CdSe are prepared first using a hot-injection technique. By controlling the crystal structure of the seed to be either wurtzite or zinc-blende, the subsequent hot-injection growth of CdS off of the seed results in either a rod-shaped or tetrapod-shaped nanocrystal, respectively. The phase and morphology of the synthesized nanocrystals are confirmed using X-ray diffraction and transmission electron microscopy, demonstrating that the nanocrystals are phase-pure and have a consistent morphology. The extinction coefficient and quantum yield of the synthesized nanocrystals are calculated using UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The rods and tetrapods exhibit extinction coefficients and quantum yields that are higher than that of the bare seeds. This synthesis demonstrates the precise arrangement of materials that can be achieved at the nanoscale by using a seeded synthetic approach.

A protocol for the seeded synthesis of rod-shaped and tetrapod-shaped multicomponent nanostructures consisting of CdS and CdSe is presented.

硒化镉/硫化镉棒和纳米四脚合成种子

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded ...

科研

化学

Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, quantum dots should be highly fluorescent and small/monodisperse in size. While commonly used cadmium-based quantum dots possess these qualities, they are potentially toxic due to the possible release of Cd2+ ions through nanoparticle degradation. Indium-based quantum dots, specifically InP/ZnS, have recently been explored as a viable alternative to cadmium-based quantum dots due to their relatively similar fluorescence characteristics and size. The synthesis presented here uses standard hot-injection techniques for effective nanoparticle growth; however, nanoparticle properties such as size, emission wavelength, and emission intensity can drastically change due to small changes in the reaction conditions. Therefore, reaction conditions such temperature, reaction duration, and precursor concentration should be maintained precisely to yield reproducible products. Because quantum dots are not inherently soluble in aqueous solutions, they must also undergo surface modification to impart solubility in water. In this protocol, an amphiphilic polymer is used to interact with both hydrophobic ligands on the quantum dot surface and bulk solvent water molecules. Here, a detailed protocol is provided for the synthesis of highly fluorescent InP/ZnS quantum dots that are suitable for use in biomedical applications.

In this protocol, the synthesis of Cd-free InP/ZnS quantum dots (QDs) is detailed. InP-based QDs are gaining popularity due to the toxicity of Cd2+ ions that may be released through nanoparticle degradation. After synthesis, QDs are solubilized in water using an amphiphilic polymer for use in biomedical applications.

镉免费的InP /硫化锌量子点的合成适合生物医学应用

Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

超分子胶体的合成与表征

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl4) to neutral gold Au(0) by reducing agents, such as sodium citrate or sodium borohydride. The extension of this method to decorate iron oxide or similar nanoparticles with gold nanoparticles to create multifunctional hybrid Fe2O3-Au nanoparticles is straightforward. This approach yields fairly good control over Au nanoparticle dimensions and loading onto Fe2O3. Additionally, the Au metal size, shape, and loading can easily be tuned by changing experimental parameters (e.g., reactant concentrations, reducing agents, surfactants, etc.). An advantage of this procedure is that the reaction can be done in air or water, and, in principle, is amenable to scaling up. The use of such optically tunable Fe2O3-Au nanoparticles for hyperthermia studies is an attractive option as it capitalizes on plasmonic heating of gold nanoparticles tuned to absorb light strongly in the VIS-NIR region. In addition to its plasmonic effects, nanoscale Au provides a unique surface for interesting chemistries and catalysis. The Fe2O3 material provides additional functionality due to its magnetic property. For example, an external magnetic field could be used to collect and recycle the hybrid Fe2O3-Au nanoparticles after a catalytic experiment, or alternatively, the magnetic Fe2O3 can be used for hyperthermia studies through magnetic heat induction. The photothermal experiment described in this report measures bulk temperature change and nanoparticle solution mass loss as functions of time using infrared thermocouples and a balance, respectively. The ease of sample preparation and the use of readily available equipment are distinct advantages of this technique. A caveat is that these photothermal measurements assess the bulk solution temperature and not the surface of the nanoparticle where the heat is transduced and the temperature is likely to be higher.

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

We describe the synthesis and properties of multifunctional Fe2O3-Au nanoparticles produced by a wet chemical approach and investigate their photothermal properties using laser irradiation. The composite Fe2O3-Au nanoparticles retain the properties of both materials, creating a multifunctional structure with excellent magnetic and plasmonic properties.

多功能混合铁<sub&gt; 2</sub&gt; 0<sub&gt; 3</sub&gt; -Au纳米粒子高效的电浆暖气

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl4) to ...

工程学

Synthesis of Ligand-free CdS Nanoparticles within a Sulfur Copolymer Matrix

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature solvents. These coordinating ligands help solubilize and stabilize the nanoparticles while in solution, and can influence the resulting size and reactivity of the nanoparticles during their formation. Despite the ubiquity of using ligands during synthesis, the presence of aliphatic ligands on the nanoparticle surface can result in a number of problems during the end use of the nanoparticles, necessitating further ligand stripping or ligand exchange procedures. We have developed a way to synthesize cadmium sulfide (CdS) nanoparticles using a unique sulfur copolymer. This sulfur copolymer is primarily composed of elemental sulfur, which is a cheap and abundant material. The sulfur copolymer has the advantages of operating both as a high temperature solvent and as a sulfur source, which can react with a cadmium precursor during nanoparticle synthesis, resulting in the generation of ligand free CdS. During the reaction, only some of the copolymer is consumed to produce CdS, while the rest remains in the polymeric state, thereby producing a nanocomposite material. Once the reaction is finished, the copolymer stabilizes the nanoparticles within a solid polymeric matrix. The copolymer can then be removed before the nanoparticles are used, which produces nanoparticles that do not have organic coordinating ligands. This nascent synthesis technique presents a method to produce metal-sulfide nanoparticles for a wide variety of applications where the presence of organic ligands is not desired.

Herein we present a method to synthesize ligand-free cadmium sulfide (CdS) nanoparticles based on a unique sulfur copolymer. The sulfur copolymer operates as a high temperature solvent and a sulfur source during the nanoparticle synthesis and stabilizes the nanoparticles after the reaction.

a硫磺共聚物基质内的免费配体硫化镉纳米粒子的合成

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

纳米粒子 - 聚合物复合材料使用直接荧光成像的先进成分分析

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

通过活性表面生长机制合成基片束缚金纳米线

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of their interactions with cell membranes, lipid bilayers, and viruses. The hydrophilic ligands make these particles colloidally stable in aqueous solutions and the combination with hydrophobic ligands creates an amphiphilic particle that can be loaded with hydrophobic drugs, fuse with the lipid membranes, and resist nonspecific protein adsorption. Many of these properties depend on nanoparticle size and the composition of the ligand shell. It is, therefore, crucial to have a reproducible synthetic method and reliable characterization techniques that allow the determination of nanoparticle properties and the ligand shell composition. Here, a one-phase chemical reduction, followed by a thorough purification to synthesize these nanoparticles with diameters below 5 nm, is presented. The ratio between the two ligands on the surface of the nanoparticle can be tuned through their stoichiometric ratio used during synthesis. We demonstrate how various routine techniques, such as transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectrometry, are combined to comprehensively characterize the physicochemical parameters of the nanoparticles.

Amphiphilic gold nanoparticles can be used in many biological applications. A protocol to synthesize gold nanoparticles coated by a binary mixture of ligands and a detailed characterization of these particles is presented.

两栖金纳米粒子的合成与表征

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of ...

Preparation of Silver-Palladium Alloyed Nanoparticles for Plasmonic Catalysis under Visible-Light Illumination

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular transformations. This opens possibilities for the use of visible or near-IR light as a sustainable input to drive and control reactions when plasmonic nanoparticles supporting LSPR excitation in these ranges are employed as catalysts. Unfortunately, this is not the case for several catalytic metals such as palladium (Pd). One strategy to overcome this limitation is to employ bimetallic NPs containing plasmonic and catalytic metals. In this case, the LSPR excitation in the plasmonic metal can contribute to accelerate and control transformations driven by the catalytic component. The method reported herein focuses on the synthesis of bimetallic silver-palladium (Ag-Pd) NPs supported on ZrO2 (Ag-Pd/ZrO2) that acts as a plasmonic-catalytic system. The NPs were prepared by co-impregnation of corresponding metal precursors on the ZrO2 support followed by simultaneous reduction leading to the formation of bimetallic NPs directly on the ZrO2 support. The Ag-Pd/ZrO2 NPs were then used as plasmonic catalysts for the reduction of nitrobenzene under 425 nm illumination by LED lamps. Using gas chromatography (GC), the conversion and selectivity of the reduction reaction under the dark and light irradiation conditions can be monitored, demonstrating the enhanced catalytic performance and control over selectivity under LSPR excitation after alloying non-plasmonic Pd with plasmonic metal Ag. This technique can be adapted to a wide range of molecular transformations and NPs compositions, making it useful for the characterization of the plasmonic catalytic activity of different types of catalysis in terms of conversion and selectivity.

Presented here is a protocol for the synthesis of silver-palladium (Ag-Pd) alloy nanoparticles (NPs) supported on ZrO2 (Ag-Pd/ZrO2). This system allows for harvesting energy from visible light irradiation to accelerate and control molecular transformations. This is illustrated by nitrobenzene reduction under light irradiation catalyzed by Ag-Pd/ZrO2 NPs.

在可见光照射下为质子催化准备银-铂合金纳米粒子

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular ...

Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production

A method for facile synthesis of nanostructured catalysts supported on carbon nanotubes with atomically dispersed cobalt and nitrogen dopant is presented herein. The novel strategy is based on a facile one-pot pyrolysis treatment of cobalt (II) acetylacetonate and nitrogen-rich organic precursors under Ar atmosphere at 800 &#176;C, resulting in the formation of Co- and N- co-doped carbon nanotube with earthworm-like morphology. The obtained catalyst was found to have a high density of defect sites, as confirmed by Raman spectroscopy. Here, cobalt (II) nanoparticles were stabilized on the atomically dispersed cobalt- and nitrogen-doped carbon nanotubes. The catalyst was confirmed to be effective in the catalytic hydrolysis of ammonia borane, in which the turnover frequency was 5.87 mol H2&#183;molCo-1&#183;min-1, and the specific hydrogen generation rate was determined to be 2447 mL H2&#183;gCo-1&#183;min-1. A synergistic function between the Co nanoparticle and the doped carbon nanotubes was proposed for the first time in the catalytic hydrolysis of ammonia borane reaction under a mild condition. The resulting hydrogen production with its high energy density and minimal refueling time could be suitable for future development as energy sources for mobile and stationary applications such as road trucks and forklifts in transport and logistics.

Here, we present a protocol to synthesize Co nanoparticles supported on carbon nanotubes with Co- and N- dopants for hydrogen productions.

碳纳米管负载掺杂Co和N原子金属纳米粒子的合成及其在制氢中的催化应用

A method for facile synthesis of nanostructured catalysts supported on carbon nanotubes with atomically dispersed cobalt and nitrogen dopant is presented ...