Seifert Julia S, Nees Nico, Khan Hamzah, Traoré Nabi E, Drobek Dominik, Peukert Wolfgang, Apeleo Zubiri Benjamin, Spiecker Erdmann, Stingl Michael, Pflug Lukas, Klupp Taylor Robin N
Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 4, 91058 Erlangen, Germany.
Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstr. 9a, 91058 Erlangen, Germany.
Nanoscale. 2024 Oct 24;16(41):19284-19297. doi: 10.1039/d4nr02516d.
Plasmonic nanoparticles have intriguing optical properties which make them suitable candidates for sensing or theranostic applications. Anisotropic patchy particles, where metal is locally deposited on the surface of a core particle, exhibit plasmon resonances that can be specifically adjusted for these applications. However, many existing synthesis routes are complex, yield too little material, or provide particles with limited optical tunability. In this work, we present a simple and scalable continuous flow synthesis of gold-on-polystyrene patchy particles with widely adjustable optical properties. By increasing the chloride concentration in the electroless deposition of gold, we slow down the redox reduction kinetics and obtain a dense patch morphology as well as a reduced nucleation rate. The latter is counteracted by introducing a low-level seeding approach where a small number of gold nanocrystals heterocoagulate with the core particles prior to patch growth. Seeding and patch growth are performed in a continuous flow set-up with two T-shaped milli-mixers. The resulting patchy particle samples exhibit a tunable dipolar plasmon peak between 600 nm and 1100 nm. We also investigate the structure-property relationship for our gold patchy particles using finite element method simulations. After identifying a suitable patch shape model, we elucidate the influence of individual geometric parameters on the optical properties and show that the relationship holds true for a large range of patch coverages. Finally, we apply the relationship to explain the time-dependent change in the optical properties of as-synthesized patches by correlating it with the patch shape transformation revealed by electron microscopy.
等离子体纳米粒子具有引人入胜的光学特性，这使其成为传感或诊疗应用的合适候选材料。各向异性的补丁状粒子，即金属局部沉积在核心粒子表面，表现出可针对这些应用进行特定调节的等离子体共振。然而，许多现有的合成路线复杂、产量过低，或提供的粒子光学可调性有限。在这项工作中，我们展示了一种简单且可扩展的连续流动合成方法，用于制备具有广泛可调光学特性的聚苯乙烯上的金补丁状粒子。通过在金的化学沉积中增加氯化物浓度，我们减缓了氧化还原还原动力学，获得了致密的补丁形态以及降低的成核速率。后者可通过引入低水平的晶种方法来抵消，即在补丁生长之前，少量金纳米晶体与核心粒子异质凝聚。晶种和补丁生长在带有两个T形微型混合器的连续流动装置中进行。所得的补丁状粒子样品在600纳米至1100纳米之间呈现出可调的偶极等离子体峰。我们还使用有限元方法模拟研究了我们的金补丁状粒子的结构-性能关系。在确定了合适的补丁形状模型后，我们阐明了各个几何参数对光学性能的影响，并表明这种关系在很大范围的补丁覆盖率内都成立。最后，我们通过将其与电子显微镜揭示的补丁形状转变相关联，应用这种关系来解释合成后补丁光学性能随时间的变化。
