Name: plasmonic trapping and release of nanoparticles in a monitoring environment
Uploaded: 2017-04-04T11:00:00.000+00:00
Duration: 9 min 13 s
Description: Watch this Scientific Journal Video about Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment at JoVE.com

这个工作是由ICT R＆MSIP / IITP（R0190-15-2040，内容配置管理系统的开发和使用智能材料三维打印模拟器）的D程序的支持。

注意:使用前请所有有关材料安全法规。几个在微芯片制造中使用的化学品是剧毒和致癌性。进行光刻和蚀刻工艺的情况下，包括使用工程控制（通风柜，热板，和对准器）和个人防护设备（安全眼镜，手套，实验室外套，全长裤和关闭的请使用所有适当的安全实践-toe鞋）。 1. PDMS微通道的制作<ol><li>通过光刻工艺微通道模具的制造<ol><li>完全4英寸Si晶片表面用piranha清洁（ 图1a）上除去异物。在以3:1的比例混合的硫酸（H 2 SO 4）和过氧化氢（H 2 O 2）:1，使在盘的食人鱼溶液。通过逐渐加入少量的强酸（H 2 O混合<suB&gt; 2）的弱酸（H 2 SO 4）;反转该顺序可能会导致由于高反应性强酸的爆炸。 </li><li>浸入晶片在10分钟食人鱼溶液。接着，浸入去离子（DI）水的晶片3分钟以除去残留的食人鱼溶液。冲洗晶片用流动的去离子水10秒。重复漂洗过程3次，并干燥以N 2气体以除去剩余的DI。 </li><li>放置在晶片上的热板上20分钟在180℃下进一步脱水的晶片。 </li><li>以1500rpm（ 图1b）倾5毫升在晶片和旋涂45秒的顶部上的负性光刻胶的;旋涂后，光致抗蚀剂珠粒在晶片边缘处创建，因为光致抗蚀剂的相对高的粘度。 </li><li>平衡在流平支架5小时通过平坦化光致抗蚀剂涂覆的晶片。 </li><li>放置光致抗蚀剂涂覆的晶片在热板上在65 12分钟℃，35分钟，在95℃，并在65℃（软烤）12分钟。 </li><li>固定在掩模保持器和矫正器的基片台上的软烘焙晶片薄膜掩模。暴露于紫外（UV）光下43号在650毫焦/厘米2以固化光致抗蚀剂。 </li><li>放置在热板上进行5分钟的晶片在65℃下，在95℃下15分钟，并在65°C（曝光后烘焙）5分钟。 </li><li>浸泡在光刻胶显影剂晶片30分钟，以除去未固化的光致抗蚀剂。 </li><li>冲洗用异丙醇（IPA）中，用N 2气体的干式晶片以除去剩余的IPA。 </li></ol></li><li>在PDMS微通道的制造<ol><li>处理晶片，并以200瓦使用大气等离子体机25的功率光致抗蚀剂模，持续1分钟的表面上; CH 4的气体流量和他应该是6和30 SCCM，分别。执行此疏水处理，容易拆卸聚D-从晶片和光致抗蚀剂模（ 图1c）的表面imethylsiloxane（PDMS）微通道。 </li><li>制备通过混合PDMS基并以10比固化剂的PDMS溶液:1。搅拌2分钟该混合物。 </li><li>放置一个陪替氏培养皿内的晶片（150毫米×15毫米），加入PDMS溶液的100毫升。除去从使用干燥器搅拌创建的气泡。 </li><li>放置在烘箱2个小时培养皿在80℃下以固化PDMS溶液（ 图1d和h）。 </li><li>沿微通道PDMS用刀片的轮廓切割并从晶片分离它;所制造的微通道PDMS应具有以下尺寸:13姆·隆恩，300微米宽和150微米高（ 图1E，F和I）。 注:两种类型的孔是由一个微穿刺产生的插入单模光纤（SMF）电缆和管（入口a第二对PDMS微通道（ 图1克出口））。的SMF电缆用于发射激光束到研磨上的金板中的纳米孔。该管被用来插入/提取从PDMS微通道中的粒子溶液至/。 </li><li>穿刺1.5毫米的入口和出口孔在所述PDMS微通道的每一端。穿刺在PDMS微通道的中心的0.3mm的SMF电缆孔。 </li></ol></li></ol> 2.镀金的蚀刻处理<ol><li>准备市售的金板上，以25×6.25毫米2（ 图2a）的尺寸。 </li><li>在黄金板块具有以下清洁程序删除任何异物。清洁在由丙酮，甲醇和去离子水浸渍，每次5分钟以下顺序。 </li><li>冲洗金板用DI水洗涤3次10秒，并用N 2气干燥该板以除去剩余的去离子水。 </li><li>将在金盘上用热板在180℃下20分钟后，完全除去任何剩余的水分。 </li><li>在3,000rpm下倾0.5mL的在金板和旋涂40秒六甲基二硅烷（HMDS）的。 </li><li>在3,000rpm下倾0.5mL的正性光刻胶的上旋涂HMDS的顶部和旋涂40秒（ 图2b）。 </li><li>放置光致抗蚀剂涂覆的金板上，在110℃（软烤）热板90秒。 </li><li>固定玻璃晶片上的薄膜掩模和放置软烤金板基片台上。暴露于UV光4.5 s的64毫焦耳/厘米2，以溶解光致抗蚀剂。 </li><li>沉浸金板在光致抗蚀剂显影剂1分钟以除去溶解的光致抗蚀剂（ 图2c）。冲洗金板用DI水，并用N 2气干燥。 </li><li>在28埃/秒的刻蚀速率以去除暴露的Au（ 图2d）沉浸在金蚀刻剂45秒金板。冲洗金板DI水:r和用N 2气干燥。 </li><li>以25埃/秒的刻蚀速率，以除去暴露的Ti（ 图2e）浸泡在钛蚀刻剂为5秒的金板。冲洗金板用DI水，并用N 2气干燥。 </li><li>通过在丙酮，甲醇，和去离子水浸渍3分钟每个（ 图2f）拆下上的金板中的剩余的光刻胶;沉浸在书面顺序板。 </li><li>冲洗金板用DI水3次，持续10秒。干用N 2气以除去去离子水。 </li><li>放置在热板上的金板3分钟，在120℃以完全除去水分;所产生的金块应该是400×150微米2（ 图2H）。 </li><li>轧机在使用这是后蚀刻（ 图2G和ⅰ）制造的金块的中心的聚焦离子束（FIB）为400nm的纳米孔。创建370纳米圈图案集中于金BL玉珠用离子在28 Pa下3秒加速30千伏的电压。 </li></ol> 3.微芯片的大会<ol><li>治疗PDMS微通道和金板的两个表面1分钟用O 2等离子体将它们连同等离子体体系在80 W的功率和825毫托25的压力连接。 注:这是特别难以将其与精密附着由于黄金块和PDMS微通道都在微米级。因此，使用对准器具有照相机和手动载物台。 </li><li>修复被用于附接膜掩模对准器（ 图3a）的阴罩保持架的玻璃晶片。 </li><li>附上O 2 -等离子体处理的PDMS微通道到玻璃晶片;因为PDMS是亲水性的，它会容易地附连到玻璃晶片没有任何粘附溶液。固定对准器（ 图3a）的基片台上的金板。 </li><li>找到个的中心ÈSMF电缆孔和金块，它们在同一轴线上对准，使用相机上的对准器。解除手动台将两个部分（ 图3b和c）结合起来。 </li></ol> 4.改进由PDMS涂层Microchip的侧的表面粗糙度的注:金板的400×150微米2固定尺寸是比较困难比PDMS材料切出。因此，为了分离从晶片的PDMS微通道，一个刀片用于切割出比金更大的板片。两个部分合并后，将PDMS相对于金板的过量的部分必须被切割，使得该通道的内部可从侧用显微镜（ 图4a）被观察到。然而，切断面，其被用作窗户，具有高的表面粗糙度，并因此产生在信道流动的颗粒混浊图像（ 图图4b）。再次进行涂层与PDMS解决方案来解决这个问题。 <ol><li>通过在10混合PDMS基料和固化剂制备PDMS溶液:1的比例，并搅拌2分钟。 </li><li>倾将2mL PDMS溶液在培养皿中，并在1000rpm下（ 图4c）进行旋涂30秒。 </li><li>地方将要被定位在培养皿上（ 图4d）的显微镜微芯片表面。放置在烘箱中1个小时培养皿在80℃下以固化PDMS溶液。 </li><li>切微芯片和使用刀片PDMS的边界，并随后从培养皿分离它（ 图4e中，f）。 </li></ol> 5.激光耦合到插入SMF电缆到Microchip 注:对于等离子体激元镊子系统中，使用的光纤入射的激光具有1064纳米波长。的SMF电缆使用，因为INCI的直径凹痕激光（5毫米）的过巨大在研磨在微芯片内的金块（400×150微米2）纳米孔以发射激光束。的SMF电缆的包层直径为125μm。因此，入射的激光和SMF电缆必须连接。 <ol><li>连接安装在SMF耦合器40X物镜的显微镜物镜。固定在SMF耦合器的光纤夹具的SMF电缆。对准入射激光束，以填补在物镜的后孔。 </li><li>通过调节装配在SMF耦合器三轴手动载物台聚焦激光束到SMF电缆的芯。 </li><li>插入SMF电缆的另一端插入微芯片的SMF电缆孔。测量之前，在纤维光缆的边缘插入的激光功率，因为​​在微芯片固定光缆不能被拆卸。 </li><li>使用环氧树脂胶以阻挡流动的颗粒溶液从SMF驾驶室之间的间隙的泄漏密封SMF电缆孔勒孔（300μm）和SMF电缆（125微米）的包层;所插入的光纤电缆的端部不能进入所述微通道，以避免流体流动。手动使用视觉反馈，使得其垂直于金块承载纳米孔对齐纤维电缆。 </li></ol> 6.单的电浆俘获的荧光聚苯乙烯粒子在微芯片<ol><li>连接注射器，其填充有颗粒溶液，于注射器微型泵。放置玻璃盖片上的荧光显微镜的样品台上。连接管，以微芯片的入口/出口孔。放置涂覆的PDMS微芯片表面上的盖玻璃的顶部。 </li><li>通过观察与安装在荧光显微镜相机通道的内部微芯片正交于60X水浸物镜透镜位置。用透明胶带固定微到位。微芯片的入口管连接与注射器NEedle。 </li><li>通过控制为20μm/ s的微型泵插入颗粒溶液到微芯片。此时，确认该荧光体粒子可很好的沟道当荧光灯接通时观察到。 </li><li>等待，直到颗粒溶液从微芯片的出口离开。将速度设置为3.4微米/秒。 </li><li>转动激光光源装置，使得其发射激光到所述纳米孔;所述荧光颗粒将在纳米孔的边缘被捕获。 </li><li>通过控制微型泵，直到截留颗粒逃逸斜坡在0.4微米/秒的增量流体速度。测量流体的速度时被俘获颗粒逃逸。获得使用该测流体速度各激光强度最大的捕获力。 </li></ol>

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Nanotechnol. 9 (4), 295-299 (2014).</li><li>Chen, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+optical+trapping+and+arrangement+of+nano-objects+in+a+plasmonic+nanocavity.">Enhanced optical trapping and arrangement of nano-objects in a plasmonic nanocavity.</a> Nano Lett. 12 (1), 125-132 (2011).</li><li>Wang, K., Schonbrun, E., Steinvurzel, P., Crozier, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trapping+and+rotating+nanoparticles+using+a+plasmonic+nano-tweezer+with+an+integrated+heat+sink.">Trapping and rotating nanoparticles using a plasmonic nano-tweezer with an integrated heat sink.</a> Nat. Commun. 2, 469 (2011).</li><li>Byun, D., Cho, S. J., Kim, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+a+flexible+penetrating+microelectrode+array+for+use+on+curved+surfaces+of+neural+tissues.">Fabrication of a flexible penetrating microelectrode array for use on curved surfaces of neural tissues.</a> J. Micromech. Microeng. 23, 125010 (2013).</li></ol>

作者什么都没有透露。

的SMF电缆被插入在微芯片上的SMF电缆孔， 如图6a的矩形点阵。因为SMF电缆孔比电缆外径大，环氧树脂胶用于密封所述间隙以阻挡流动的颗粒溶液的泄漏。环氧树脂胶的应用程序之前，金块和电缆边缘应该同轴地用手使用显微镜对准。虽然它是理想的插入的电缆边缘和纳米孔被同轴地对准，有轻微的不对准是可以容忍的，因为一旦它从0.14 NA SMF电缆边缘的端部发射的激光束发散，光束影...

操纵微尺度对象的能力是许多微/纳米实验中不可缺少的功能。直接接触操作会损坏操纵对象。释放之前保持的对象也正是因为静摩擦问题具有挑战性。为了克服这些问题，采用的流体1，电动2，磁3，或光子力4，5，6，7几个间接方法，8已经被提出。使用光子力电浆镊子是基于非凡场增强几个数量级比入射光强度大9的物理性质。这种极其强烈的场增强使极小的纳米粒子的捕集。例如，已显示，以固定和操纵纳米级的对象，如聚苯乙烯颗粒7，10，11，12，13，14，聚合物链15，蛋白质16，量子点17，和DNA分子8,18。如果没有电浆镊子，它是很难被诱捕的纳米粒子，因为它们很快消失在有效地检查之前，他们或者是因为它们是由于激光的高强度受损。 许多电浆研究中使用的各种纳米级金结构。我们可以分类的金结构作为突出纳米盘类型12，13，14，15，19 <s向上&gt;，20，21或抑制纳米孔类型7，8，10，11，22，23。在成像的方便的观点出发，纳米盘类型是比纳米孔类型的更多合适的，因为对于后者，金基材可以妨碍观察视野。此外，等离激元俘获发生等离子结构附近，使得观测甚至更具挑战性。据我们所知，在纳米孔类型的电浆诱捕用间接散射信号，只有通过验证。但是，没有成功的直接观察，如显微图像，已报告。很少有研究描述俘获粒子的位置。这样的一个结果被王等人提出。他们创建的金基板上的金支柱和观察到的所述p使用荧光显微镜24条运动。然而，这仅仅是为了在平行于光束轴的方向监测侧向运动无效。 在本文中，我们引入新的流体微芯片的设计和制造过程。使用这种芯片，我们证明plasmonically捕获粒子的监测，无论是在方向平行和垂直的电浆纳米结构。此外，我们通过增加流体速度找到在微芯片的引爆速度测量固定化的粒子的最大力量。这项研究是独一无二的，因为在电浆镊子大多数研究不能定量地显示在他们的实验设置中使用的最大阱力。

<table><tbody><tr><td>Negative photoresist&amp;nbsp;</td><td>MicroChem</td><td>SU-8 2075</td><td></td></tr><tr><td>Developer</td><td>MicroChem</td><td>SU-8 Developer</td><td></td></tr><tr><td>Positive photoresist&amp;nbsp;</td><td>Merck Ltd.</td><td>AZ GXR-601</td><td></td></tr><tr><td>AZ Photoresist Developers</td><td>Merck Ltd.</td><td>AZ 300 MIF</td><td></td></tr><tr><td>HMDS</td><td>Merck Ltd.</td><td>AZ Adhesion Promoter</td><td></td></tr><tr><td>Aligner</td><td>Midas System</td><td>MDA 400M</td><td></td></tr><tr><td>Atmospheric plasma machine&amp;nbsp;</td><td>Atmospheric Process&lt;br/&gt; Plasma Co.</td><td>IDP-1000</td><td></td></tr><tr><td>Polydimethylsiloxane (PDMS)</td><td>Dow Corning</td><td>Sylgard 184 A/B</td><td></td></tr><tr><td>Gold coated test slides</td><td>EMF Co.</td><td>TA124(Ti/Au)</td><td></td></tr><tr><td>Au etchant&amp;nbsp;</td><td>Transene Inc.</td><td>TFA</td><td></td></tr><tr><td>Ti etchant&amp;nbsp;</td><td>Transene Inc.</td><td>TFT</td><td></td></tr><tr><td>40X objective lens&amp;nbsp;</td><td>Edmund Optics</td><td>40X DIN</td><td></td></tr><tr><td>60X water immersion&lt;br/&gt; objective lens&amp;nbsp;</td><td>Olympus</td><td>LUMPLFLN 60XW</td><td></td></tr><tr><td>Optical fiber incident laser&amp;nbsp;</td><td>IPG Photonic</td><td>YLR 10</td><td></td></tr><tr><td>SMF coupler</td><td>Thorlabs</td><td>MBT612D/M</td><td></td></tr><tr><td>Syringe micropump</td><td>Harvard</td><td>PC2 70-4501</td><td></td></tr><tr><td>Fluorescent microscope&amp;nbsp;</td><td>Olympus</td><td>IX-51</td><td></td></tr><tr><td>Plasma system</td><td>Femto Science Inc</td><td>CUTE-MPR</td><td></td></tr></tbody></table>

plasmonic trapping and release of nanoparticles in a monitoring environment

电浆镊子使用表面等离子体激元来限制极化纳米级物体。在电浆镊子的各种设计，只有少数可以观察到固定的颗粒。此外，研究有限数量的实验测得的颗粒上的可施加的力。这些设计可以被分类为突出纳米盘类型或抑制纳米孔类型。对于后者，显微镜观察是极具挑战性。在本文中，一个新的等离激元镊子系统中引入来监测颗粒，无论是在平行方向和垂直于等离子体激元纳米孔结构的对称轴。通过此功能，我们观察到纳米孔的边缘附近的每个粒子的运动。此外，我们可以定量评估采用了全新的流体通道的最大阱力。

将PDMS微通道和纳米孔金板的制造方法示于图1和2。的方法，所述两个部件结合和实际微芯片在图3中所示。所述PDMS切成从微芯片的侧面露出的通道的内部。然而，这是难以观察到，因为在切割平面的表面粗糙度在通道中流动的粒子。因此，我们介绍了PDMS涂覆方法来解决这个问题，如图4中所示 。 <p class="jove...

Watch this Scientific Journal Video about Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment at JoVE.com

Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

并入电浆镊子的微芯片制造工艺在这里呈现。微芯片使捕集粒子的成像来测量最大俘获力。

电浆捕获和纳米粒子的释放在监控环境

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few ...

plasmonic-trapping-release-nanoparticles-monitoring

Universidad San Sebastian

Research

JoVE Journal

Engineering

7.6K 次观看.  Korea Basic Science Institute (KBSI). 并入电浆镊子的微芯片制造工艺在这里呈现。微芯片使捕集粒子的成像来测量最大俘获力。 

视频: Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

多晶硅薄膜太阳能电池电浆增强光捕获

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

科研

工程学

Optical Trapping of Nanoparticles

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3.
A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure.
The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres.

The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.

纳米粒子的光学捕获

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping ...

Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular organelles 2,3, as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope 4,5 at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale.

The system described herein employs a traditional optical trap as well as an independent holographic optical trapping line, capable of creating and manipulating multiple traps. This allows for the creation of complex geometric arrangements of refractive particles while also permitting simultaneous high-speed, high-resolution measurements of the activity of biological enzymes.

高分辨率显微镜与常规和全息光学捕获能力建设

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular ...

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation

A method to manipulate the position and orientation of submicron particles nondestructively would be an incredibly useful tool for basic biological research. Perhaps the most widely used physical force to achieve noninvasive manipulation of small particles has been dielectrophoresis(DEP).1 However, DEP on its own lacks the versatility and precision that are desired when manipulating cells since it is traditionally done with stationary electrodes. Optical tweezers, which utilize a three dimensional electromagnetic field gradient to exert forces on small particles, achieve this desired versatility and precision.2 However, a major drawback of this approach is the high radiation intensity required to achieve the necessary force to trap a particle which can damage biological samples.3 A solution that allows trapping and sorting with lower optical intensities are optoelectronic tweezers (OET) but OET's have limitations with fine manipulation of small particles; being DEP-based technology also puts constraint on the property of the solution.4,5
This video article will describe two methods that decrease the intensity of the radiation needed for optical manipulation of living cells and also describe a method for orientation control. The first method is plasmonic tweezers which use a random gold nanoparticle (AuNP) array as a substrate for the sample as shown in Figure 1. The AuNP array converts the incident photons into localized surface plasmons (LSP) which consist of resonant dipole moments that radiate and generate a patterned radiation field with a large gradient in the cell solution. Initial work on surface plasmon enhanced trapping by Righini et al and our own modeling have shown the fields generated by the plasmonic substrate reduce the initial intensity required by enhancing the gradient field that traps the particle.6,7,8 The plasmonic approach allows for fine orientation control of ellipsoidal particles and cells with low optical intensities because of more efficient optical energy conversion into mechanical energy and a dipole-dependent radiation field. These fields are shown in figure 2 and the low trapping intensities are detailed in figures 4 and 5. The main problems with plasmonic tweezers are that the LSP's generate a considerable amount of heat and the trapping is only two dimensional. This heat generates convective flows and thermophoresis which can be powerful enough to expel submicron particles from the trap.9,10 The second approach that we will describe is utilizing periodic dielectric nanostructures to scatter incident light very efficiently into diffraction modes, as shown in figure 6.11 Ideally, one would make this structure out of a dielectric material to avoid the same heating problems experienced with the plasmonic tweezers but in our approach an aluminum-coated diffraction grating is used as a one-dimensional periodic dielectric nanostructure. Although it is not a semiconductor, it did not experience significant heating and effectively trapped small particles with low trapping intensities, as shown in figure 7. Alignment of particles with the grating substrate conceptually validates the proposition that a 2-D photonic crystal could allow precise rotation of non-spherical micron sized particles.10 The efficiencies of these optical traps are increased due to the enhanced fields produced by the nanostructures described in this paper.

Plasmonic tweezers and photonic crystal nanostructures are shown to produce useful enhancements in the efficiency and orientation control of optically trapping micro- and nano-particles.

为增强微型和纳米操纵利用电浆和光子晶体纳米结构

A method to manipulate the position and orientation of submicron particles nondestructively would be an incredibly useful tool for basic biological ...

生物工程

Analyzing the Movement of the Nauplius 'Artemia salina' by Optical Tracking of Plasmonic Nanoparticles

We demonstrate how optical tweezers may provide a sensitive tool to analyze the fluidic vibrations generated by the movement of small aquatic organisms. A single gold nanoparticle held by an optical tweezer is used as a sensor to quantify the rhythmic motion of a Nauplius larva (Artemia salina) in a water sample. This is achieved by monitoring the time dependent displacement of the trapped nanoparticle as a consequence of the Nauplius activity. A Fourier analysis of the nanoparticle&#39;s position then yields a frequency spectrum that is characteristic to the motion of the observed species. This experiment demonstrates the capability of this method to measure and characterize the activity of small aquatic larvae without the requirement to observe them directly and to gain information about the position of the larvae with respect to the trapped particle. Overall, this approach could give an insight on the vitality of certain species found in an aquatic ecosystem and could expand the range of conventional methods for analyzing water samples.

Analyzing the Movement of the Nauplius 'Artemia salina' by Optical Tracking of Plasmonic Nanoparticles

We use optical tracking of plasmonic nanoparticles to probe and characterize the frequency movements of aquatic organisms.

分析无节幼体的运动“<em&gt;卤虫</em&gt;&#39;由电浆纳米粒子的光学跟踪

We demonstrate how optical tweezers may provide a sensitive tool to analyze the fluidic vibrations generated by the movement of small aquatic organisms. A ...

Fabrication and Operation of a Nano-Optical Conveyor Belt

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and&#160;limits the&#160;resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.

The scalability and resolution of conventional optical manipulation techniques are limited by diffraction. We circumvent the diffraction limit and describe a method of optically transporting nanoparticles across a chip using a gold surface patterned with a path of closely spaced C-shaped plasmonic resonators.

一个纳米光输送带的制作和操作

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological ...

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and artificial nanomotors and may provide new routes towards single cell analysis, studies of non-equilibrium thermodynamics, and mechanical actuation of nanoscale systems. A facile way to drive rotation is to use focused circularly polarized laser light in optical tweezers. Using this approach, metallic nanoparticles can be operated as highly efficient scattering-driven rotary motors spinning at unprecedented rotation frequencies in water.
In this protocol, we outline the construction and operation of circularly-polarized optical tweezers for nanoparticle rotation and describe the instrumentation needed for recording the Brownian dynamics and Rayleigh scattering of the trapped particle. The rotational motion and the scattering spectra provides independent information on the properties of the nanoparticle and its immediate environment. The experimental platform has proven useful as a nanoscopic gauge of viscosity and local temperature, for tracking morphological changes of nanorods and molecular coatings, and as a transducer and probe of photothermal and thermodynamic processes.

Plasmonic gold nanorods can be trapped in liquids and rotated at kHz frequencies using circularly-polarized optical tweezers. Introducing tools for Brownian dynamics analysis and light scatteringspectroscopy leads to a powerful system for research and application in numerous fields of science.

轻型金纳米旋转电机系统的施工与运行

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and ...

Trapping of Micro Particles in Nanoplasmonic Optical Lattice

The plasmonic optical tweezer has been developed to overcome the diffraction limits of the conventional far field optical tweezer. Plasmonic optical lattice consists of an array of nanostructures, which exhibit a variety of trapping and transport behaviors. We report the experimental procedures to trap micro-particles in a simple square nanoplasmonic optical lattice. We also describe the optical setup and the nanofabrication of a nanoplasmonic array. The optical potential is created by illuminating an array of gold nanodiscs with a Gaussian beam of 980 nm wavelength, and exciting plasmon resonance. The motion of particles is monitored by fluorescence imaging. A scheme to suppress photothermal convection is also described to increase usable optical power for optimal trapping. Suppression of convection is achieved by cooling the sample to a low temperature, and utilizing the near-zero thermal expansion coefficient of a water medium. Both single particle transport and multiple particle trapping are reported here.

We describe a procedure to optically trap micro-particles in nanoplasmonic optical lattice.

Nanoplasmonic 光学晶格中微粒子的俘获

The plasmonic optical tweezer has been developed to overcome the diffraction limits of the conventional far field optical tweezer. Plasmonic optical ...

Monitoring Conformational Dynamics of Single Unmodified Proteins using Plasmonic Nanotweezers

Current single-molecule techniques to characterize proteins typically require labels, tethers, or the use of non-native solution conditions. Such changes can alter protein biophysics and reduce the usefulness of the data acquired. Plasmonic nanotweezers is a technique that uses localized surface plasmon resonance (LSPR) on gold nanostructures to enhance the electric field within a confined hotspot region. This field enhancement allows for the use of low laser powers to trap single nanoparticles far smaller than conventional optical tweezers, down to only a few nanometers in diameter, such as single proteins. Trapping of single protein molecules within the hotspot region induces a shift in the local refractive index (nprotein &#62; nwater), altering light scattering as a product of the molecule&#39;s polarisability, which is affected by its volume, shape anisotropy, and refractive index. An avalanche photodiode (APD) collects the subsequent changes in light scattering. These alterations can then be analyzed to determine changes in the trapped molecule, including its size, global conformation, and dynamics of conformational change over time. The incorporation of microfluidics within the system allows for controlled environmental changes and real-time monitoring of their subsequent effects on the molecule. In this protocol, we demonstrate the steps to trap single protein molecules, alter their environmental solution conditions, and monitor their corresponding conformational changes using a plasmonic nanotweezers system.

Plasmonic nanotweezers use localized surface plasmon resonance in gold nanostructures to trap single nanoparticles, including proteins, within a nanometer-scale optical field. Changes in the scattered signal reveal protein presence and conformational dynamics, enabling monitoring without fluorophore modifications or surface tethering.

使用等离子体纳米镊子监测单个未修饰蛋白质的构象动力学

Current single-molecule techniques to characterize proteins typically require labels, tethers, or the use of non-native solution conditions. Such changes ...

Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations

Surface-enhanced Raman spectroscopy (SERS) enables the ultrasensitive detection of analyte molecules in various applications due to the enhanced electric field of metallic nanostructures. Salt-induced silver nanoparticle aggregation is the most popular method for generating SERS-active substrates; however, it is limited by poor reproducibility, stability, and biocompatibility. The present protocol integrates optical manipulation and SERS detection to develop an efficient analytical platform to address this. A 1064 nm trapping laser and a 532 nm Raman probe laser are combined in a microscope to assemble silver nanoparticles, which generate plasmonic hotspots for in situ SERS measurements in aqueous environments. Without aggregating agents, this dynamic plasmonic silver nanoparticle assembly enables an approximately 50-fold enhancement of the analyte molecule signal. Moreover, it provides spatial and temporal control to form the SERS-active assembly in as low as 0.05 nM analyte-coated silver nanoparticle solution, which minimizes the potential perturbation for in vivo analysis. Hence, this optical trapping-integrated SERS platform holds great potential for efficient, reproducible, and stable molecular analyses in liquids, especially in aqueous physiological environments.

Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations

The present protocol describes a convenient approach to integrating optical trapping and surface-enhanced Raman spectroscopy (SERS) to manipulate plasmonic nanoparticles for sensitive molecular detection. Without aggregating agents, the trapping laser assembles plasmonic nanoparticles to enhance the SERS signals of target analytes for in situ spectroscopic measurements.

等离子体纳米颗粒的光学捕获用于 原位 表面增强拉曼光谱表征

Surface-enhanced Raman spectroscopy (SERS) enables the ultrasensitive detection of analyte molecules in various applications due to the enhanced electric ...

电浆捕获和纳米粒子的释放在监控环境

摘要

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此视频中的章节

多晶硅薄膜太阳能电池电浆增强光捕获

纳米粒子的光学捕获

高分辨率显微镜与常规和全息光学捕获能力建设

为增强微型和纳米操纵利用电浆和光子晶体纳米结构

分析无节幼体的运动“

一个纳米光输送带的制作和操作

轻型金纳米旋转电机系统的施工与运行

Nanoplasmonic 光学晶格中微粒子的俘获

使用等离子体纳米镊子监测单个未修饰蛋白质的构象动力学

等离子体纳米颗粒的光学捕获用于原位表面增强拉曼光谱表征

电浆捕获和纳米粒子的释放在监控环境

摘要

探索更多视频

此视频中的章节

多晶硅薄膜太阳能电池电浆增强光捕获

纳米粒子的光学捕获

高分辨率显微镜与常规和全息光学捕获能力建设

为增强微型和纳米操纵利用电浆和光子晶体纳米结构

分析无节幼体的运动“

一个纳米光输送带的制作和操作

轻型金纳米旋转电机系统的施工与运行

Nanoplasmonic 光学晶格中微粒子的俘获

使用等离子体纳米镊子监测单个未修饰蛋白质的构象动力学

等离子体纳米颗粒的光学捕获用于 原位 表面增强拉曼光谱表征

等离子体纳米颗粒的光学捕获用于原位表面增强拉曼光谱表征