用于跟踪纳米粒子自组装的液体细胞透射电子显微镜
Summary
在这里, 我们介绍了实验协议的 real-time 观察的自组装过程中使用液体细胞透射电镜。
Abstract
干燥纳米粒子的分散是建立纳米微粒自组装结构的一种通用方法, 但这一过程的机制还没有完全被理解。我们用液-细胞透射电镜 (TEM) 追踪了单个纳米粒子的运动轨迹, 以研究其组装过程的机理。在此, 我们提出的协议用于液体细胞 TEM 研究的自组装机制。首先, 我们介绍了详细的合成协议, 用于生产均匀大小的铂和硒化铅纳米颗粒。接下来, 我们介绍了用氮化硅或硅窗生产液态细胞的微细加工过程, 然后描述了液-细胞 TEM 技术的加载和成像过程。包括一些说明, 为整个过程提供有用的提示, 包括如何管理脆弱的细胞窗口。通过液-胞 TEM 跟踪的纳米粒子的单个运动表明, 蒸发引起的溶剂边界的变化影响了纳米粒子的自组装过程。溶剂的边界驱使纳米颗粒主要形成无定形的聚合体, 其次是聚集体的扁平化以产生2维 (2D) 自组装结构。这些行为也观察到不同的纳米颗粒类型和不同的液体细胞组成。
Introduction
胶体纳米粒子的自组装是有兴趣的, 因为它提供了一个机会来获得单个纳米粒子的集体物理性质11。在实际的设备规模应用中, 自组装最有效的方法之一是在基板上通过挥发性溶剂的蒸发来自我组织,6,7,8,9,10,11. 这种溶剂蒸发法是一种非平衡过程, 主要受蒸发速率和纳米粒子-基体相互作用的变化等动力学因素的影响。然而, 由于难以估计和控制的动力学因素, 机械理解纳米粒子自组装的溶剂蒸发不完全成熟。虽然原位X 射线散射研究提供了非平衡纳米粒子自组装过程的集合平均信息,12,13,14, 此技术不能确定单个纳米粒子的运动, 它们与整体轨迹的联系不能轻易地被访问。
液体细胞 TEM 是一种新的工具, 跟踪单个纳米粒子的轨迹, 使我们能够理解纳米粒子运动的不均匀性及其对合奏行为的贡献15,16, 17,18,19,202122,2324,25 26。我们以前用液体细胞 TEM 跟踪单个纳米粒子在溶剂蒸发过程中的运动, 表明溶剂边界的运动是诱导纳米粒子自组装的主要推动力18,19. 本文介绍了利用液-细胞 TEM 观察纳米粒子自组装过程的实验。首先, 我们提供了合成铂和硒化铅纳米粒子的协议, 然后介绍了 TEM 中的液细胞的制备方法, 以及如何将纳米微粒加载到液细胞中。作为代表性的结果, 我们展示了由溶剂干燥驱动的纳米粒子自组装的 TEM 电影的快照图像。通过跟踪这些电影中的单个粒子, 我们可以了解在单个纳米粒子水平上的溶剂-干燥-介导的自组装的详细机制。在自组装过程中, 氮化硅窗口上的铂纳米粒子主要跟随蒸发溶剂前缘的运动, 因为在薄溶剂层上的强毛细管力作用。其他的纳米粒子 (硒化铅) 和基体 (硅) 也有类似现象, 这表明溶剂锋的毛细管力是粒子在基底附近迁移的一个重要因素。
Protocol
1. 纳米颗粒的合成 合成铂纳米粒子 组合17.75 毫克铵铂 (iv) (NH 4 ) 2 Pt (iv) Cl 6 ), 3.72 毫克酸铵 (ii) (NH 4 ) 2 Pt (ii) Cl 4 ), 115.5 毫克四甲基溴化铵, 109 毫克聚 (基) (兆瓦: 2.9万), 10 毫升的乙二醇, 在100毫升 3-颈圆底烧瓶中搅拌棒配有橡胶隔膜. 将烧瓶与回流冷凝器一起装备, 并在真空下清洗。搅拌的反应混合物与磁?…
Representative Results
该液芯由一个顶部芯片和一个底部芯片组成, 它装有氮化硅窗口, 对电子束具有25纳米厚度的透明。顶部芯片有一个储存样品溶液和蒸发溶剂的储罐。这些芯片是通过传统的微细加工处理25。用于顶部和底部芯片的掩码分别显示在图 1a和 1b中。图 2a和 2b分别显?…
Discussion
以铂铵 (IV) 和酸铵 (II) 为原料, 用聚 (基) (PVP) 作为配体和乙二醇作为溶剂和还原剂, 合成了 7 nm 的铂纳米颗粒.27.用油进行配体交换反应, 在疏水溶剂中分散颗粒。以硒为原料, 将铅油酸酯配合物的热分解, 合成了铅化硫纳米颗粒,28 (参见参考29 , 用于详细合成的纳米晶)。由于合成的铅硒化物纳米颗粒已经被长链配体所覆盖, 这些微粒不需要配基交…
Disclosures
The authors have nothing to disclose.
Acknowledgements
我们感谢 Prof. Alivisatos 在加州大学伯克利分校和 Prof. Taeghwan 在首尔国立大学进行了有益的讨论。这项工作得到了 IBS-R006-D1 的支持。W.C.L. 感谢汉阳大学研究基金 (HY-2015-N) 的支持。
Materials
| ammonium hexachloroplatinate (IV) | Sigma-Aldrich | 204021 | |
| ammonium tetrachloroplatinate (II) | Sigma-Aldrich | 206105 | |
| tetramethylammonium bromide, 98% | Sigma-Aldrich | 195758 | |
| poly(vinylpyrrolidone) powder | Sigma-Aldrich | 234257 | Mw ~29,000 |
| ethylene glycol, anhydrous, 99.8% | Sigma-Aldrich | 324558 | |
| n-hexane, anhydrous, 95% | Samchun Chem. | H0114 | |
| ethanol, anhydrous, 99.5% | Sigma-Aldrich | 459836 | |
| oleylamine, 70% | Sigma-Aldrich | O7805 | Technical grade |
| lead(II) acetate trihydrate, 99.99% | Sigma-Aldrich | 467863 | |
| oleic acid, 90% | Sigma-Aldrich | 364525 | Technical grade |
| diphenyl ether, 99% | Sigma-Aldrich | P24101 | ReagentPlus |
| selenium powder, 99.99% | Sigma-Aldrich | 229865 | |
| tri-n-octylphosphine, 97% | Strem | 15-6655 | Air sensistive |
| Toluene, anhydrous, 99.9% | Samchun Chem. | T2419 | |
| acetone 99.8% | Daejung Chem. | 1009-2304 | |
| potassium hydroxide, 95% | Samchun Chem. | P0925 | |
| p-type silicon-on-insulator wafers | Soitec | Power-SOI | for liquid cells with silicon windows |
| tetramethylammonium hydroxide, 25% in H2O | J.T.Baker | 02-002-109 | |
| AZ 5214 E | AZ Electronic Materials | AZ 5214 E | Positive photorest |
| AZ-327 | AZ Electronic Materials | AZ-327 | AZ 5214 develper |
| indium pellets 99.98-99.99% | Kurt J. Lesker Company | EVMIN40EXEB | thermal evaporator target |
| 1,2-dichlorobenzene, >99% | TCI | D1116 | |
| pentadecane, >99% | Sigma-Aldrich | P3406 | |
| buffered oxide etch 7:1 | microchemicals | BOE 7-1 VLSI | |
| phosphoric acid, 85% | Samchun Chem. | P0449 |
References
- Shevchenko, E. V., Talapin, D. V., Kotov, N. A., O’Brien, S., Murray, C. B. Structural Diversity in Binary Nanoparticle Superlattices. Nature. 439, 55-59 (2006).
- Talapin, D. V., et al. Quasicrystalline Order in Self-Assembled Binary Nanoparticle Superlattices. Nature. 461, 964-967 (2009).
- Evers, W. H., Friedrich, H., Filion, L., Dijkstra, M., Vanmaekelbergh, D. Observation of a Ternary Nanocrystal Superlattice and Its Structural Characterization by Electron Tomography. Angew. Chem., Int. Ed. 48, 9655-9657 (2009).
- Maillard, M., Motte, L., Pileni, M. P. Rings and Hexagons Made of Nanocrystals. Adv. Mater. 13, 200-204 (2001).
- Sztrum, C. G., Rabani, E. Out-of-Equilibrium Self-Assembly of Binary Mixtures of Nanoparticles. Adv. Mater. 18, 565-571 (2006).
- Han, W., Lin, Z. Learning From "coffee Rings": Ordered Structures Enabled by Controlled Evaporative Self-Assembly. Angew. Chem., Int. Ed. 51, 1534-1546 (2012).
- Bigioni, T. P., et al. Kinetically Driven Self Assembly of Highly Ordered Nanoparticle Monolayers. Nat. Mater. 5, 265-270 (2006).
- Govor, L. V., Reiter, G., Parisi, J., Bauer, G. H. Self-Assembled Nanoparticle Deposits Formed at the Contact Line of Evaporating Micrometer-Size Droplets. Phys. Rev. E. 69, 61609 (2004).
- Kletenik-Edelman, O., et al. Drying-Mediated Hierarchical Self-Assembly of Nanoparticles: A Dynamical Coarse-Grained Approach. J. Phys. Chem. C. 112, 4498-4506 (2008).
- Kletenik-Edelman, O., Sztrum-Vartash, C. G., Rabani, E. Coarse-Grained Lattice Models for Drying-Mediated Self-Assembly of Nanoparticles. J. Mater. Chem. 19, 2872-2876 (2009).
- Rabani, E., Reichman, D. R., Geissler, P. L., Brus, L. E. Drying-mediated self-assembly of nanoparticles. Nature. 426, 271-274 (2003).
- Loubat, A., et al. Growth and Self-Assembly of Ultrathin Au Nanowires into Expanded Hexagonal Superlattice Studied by in Situ SAXS. Langmuir. 30, 4005-4012 (2014).
- Connolly, S., Fullam, S., Korgel, B., Fitzmaurice, D. Time-Resolved Small-Angle X-Ray Scattering Studies of Nanocrystal Superlattice Self-Assembly. J. Am. Chem. Soc. 120, 2969-2970 (1998).
- Lu, C., Akey, A. J., Dahlman, C. J., Zhang, D., Herman, I. P. Resolving the Growth of 3D Colloidal Nanoparticle Superlattices by Real-Time Small-Angle X-Ray Scattering. J. Am. Chem. Soc. 134, 18732-18738 (2012).
- Zheng, H., Claridge, S. A., Minor, A. M., Alivisatos, A. P., Dahmen, U. Nanocrystal Diffusion in a Liquid Thin Film Observed by in Situ Transmission Electron Microscopy. Nano Lett. 9, 2460-2465 (2009).
- Jungjohann, K. L., Bliznakov, S., Sutter, P. W., Stach, E. A., Sutter, E. A. In Situ Liquid Cell Electron Microscopy of the Solution Growth of Au-Pd Core-Shell Nanostructures. Nano Lett. 13, 2964-2970 (2013).
- Yuk, J. M., et al. High-Resolution EM of Colloidal Nanocrystal Growth Using Graphene Liquid Cells. Science. 336, 61-64 (2012).
- Park, J., et al. Direct Observation of Nanoparticle Superlattice Formation by Using Liquid Cell Transmission Electron Microscopy. ACS Nano. 6, 2078-2085 (2012).
- Lee, W. C., Kim, B. H., Choi, S., Takeuchi, S., Park, J. Liquid Cell Electron Microscopy of Nanoparticle Self-Assembly Driven by Solvent Drying. J. Phys. Chem. Lett. 8, 647-654 (2017).
- Park, J., et al. 3D Structure of Individual Nanocrystals in Solution by Electron Microscopy. Science. 349, 290-295 (2015).
- Chee, S. W., Baraissov, Z., Loh, N. D., Matsudaira, P. T., Mirsaidov, U. Desorption-Mediated Motion of Nanoparticles at the Liquid-Solid Interface. J. Phys. Chem. C. 120, 20462-20470 (2016).
- Liu, Y., Lin, X. -. M., Sun, Y., Rajh, T. In Situ Visualization of Self-Assembly of Charged Gold Nanoparticles. J. Am. Chem. Soc. 135, 3764-3767 (2013).
- Verch, A., Pfaff, M., de Jonge, N. Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy. Langmuir. 31, 6956-6964 (2015).
- Sutter, E., et al. In Situ Microscopy of the Self-Assembly of Branched Nanocrystals in Solution. Nat. Commun. 7, 11213 (2016).
- Niu, K. -. Y., Liao, H. -. G., Zheng, H. Revealing Dynamic Processes of Materials in Liquid Using Transmission Electron Microscopy. J. Vis. Exp. (70), e50122 (2012).
- Hermannsdörfer, J., de Jonge, N. Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy. J. Vis. Exp. (120), e54943 (2017).
- Tsung, C. K., et al. Sub-10 nm Platinum Nanocrystals with Size and Shape Control: Catalytic Study for Ethylene and Pyrrole Hydrogenation. J. Am. Chem. Soc. 131, 5816-5822 (2009).
- Cho, K. S., Talapin, D. V., Gaschler, W., Murray, C. B. Designing PbSe Nanowires and Nanorings through Oriented Attachment of Nanoparticles. J. Am. Chem. Soc. 127, 7140-7147 (2005).
- Manthiram, K., Beberwyck, B. J., Talapin, D. V., Alivisatos, A. P. Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals. J. Vis. Exp. (82), e50731 (2013).
- Woehl, T. J., et al. Experimental Procedures to Mitigate Electron Beam Induced Artifacts During in situ Fluid Imaging of Nanomaterials. Ultramicroscopy. 127, 53-63 (2013).
- Shin, D., et al. Growth Dynamics and Gas Transport Mechanism of Nanobubbles in Graphene Liquid Cells. Nat. Commun. 6, 6068 (2015).
Cite This Article
Kim, B. H., Heo, J., Lee, W. C., Park, J. Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles. J. Vis. Exp. (128), e56335, doi:10.3791/56335 (2017).