Particle Size Evolution during the Synthesis of Gold Nanoparticles Using In Situ Time-Resolved UV-Vis Spectroscopy: An Experimental and Theoretical Study Unravelling the Effect of Adsorbed Gold Precursor Species
Particle Size Evolution during the Synthesis of Gold Nanoparticles Using In Situ Time-Resolved UV-Vis Spectroscopy: An Experimental and Theoretical Study Unravelling the Effect of Adsorbed Gold Precursor Species
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DOI：
10.1021/acs.jpcc.0c07405
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发表时间：
2020-12-17
影响因子：
3.7
通讯作者：
Gavriilidis, Asterios
中科院分区：
文献类型：
--
作者：
Panariello, Luca;Radhakrishnan, Anand N. P.;Gavriilidis, Asterios
纳米材料合成动力学的定量分析对于理解合成和制造工艺的开发都是有价值的，并且它通常需要使用基于同步加速器的仪器，使得在开发定量动力学模型所需的大参数空间中进行实验具有挑战性。紫外-可见光谱是一种方便的技术，以规避这些困难，因为它是在大多数化学实验室，并允许快速数据采集。该技术在理论上可用于表征等离子体纳米材料的合成动力学。然而，将紫外可见光谱与所产生的纳米材料的特征（如尺寸和形状）联系起来是一项具有挑战性的任务。这项工作提出了一个详细的光谱分析的金纳米粒子的合成，通过在原位时间分辨紫外-可见光谱，重点是在纳米粒子生长过程中的颗粒表面上的金前体吸附的作用。我们发现，经典的Turkevich合成和两种不同的方法的预成型的金纳米粒子的生长表现出显着的共性在光谱的演变，解释在金前体物种和纳米粒子表面之间的相互作用。这种相互作用在基于米氏理论的模型中被解释，该模型将生长的纳米颗粒描述为具有几个埃的外壳的核-壳球体，其特征在于降低的电导率和增加的电子阻尼率。所提出的模型导致确定的纳米粒子的尺寸和浓度的演变在整个合成与文献SAXS数据具有良好的定量一致性。此外，核-壳模型能够再现在合成过程中观察到的SPR峰位置的渐进蓝移。因此，这项工作调和了Turkevich合成的“种子介导的生长”机制与Mie理论框架内光谱的时间演变，表明合成过程中观察到的独特的紫灰色色调可能与金的相互作用有关前体与生长的金纳米颗粒。
The quantitative analysis of nanomaterials synthesis kinetics is valuable both for understanding the synthesis and for development of manufacturing processes, and it usually requires the use of synchrotron-based instrumentation, making it challenging to perform experiments in the large parametric space needed to develop quantitative kinetic models. UV-vis spectroscopy represents a convenient technique to circumvent such difficulties, as it is available in most chemistry laboratories and allows fast data acquisition. This technique can in theory be used for the characterization of plasmonic nanomaterials synthesis kinetics. However, linking UV-vis spectra with characteristic features of the produced nanomaterials, such as size and shape, is a challenging task. This work presents a detailed spectroscopic analysis of gold nanoparticles syntheses via in situ time-resolved UV-vis spectroscopy, with emphasis on the role of gold precursor adsorption on the particle surface during nanoparticle growth. We show that the classic Turkevich synthesis and the growth of preformed gold nanoparticles with two different methods exhibit significant commonalities in the spectra evolution, explained in terms of the interaction between gold precursor species and the nanoparticle surface. Such interaction was accounted for in a model based on the Mie theory, describing the growing nanoparticles as core-shell spheres with an outer shell of few Angstroms characterized by reduced conductivity and increased electron damping rate. The proposed model led to the determination of the nanoparticle size and concentration evolution throughout the synthesis with good quantitative agreement against literature SAXS data. Furthermore, the core-shell model enabled the reproduction of the progressive blue-shift in the SPR peak position observed during the synthesis. Thus, this work reconciles the "seed-mediated growth" mechanism for the Turkevich synthesis with the temporal evolution of the spectra within the framework of the Mie theory, showing that the distinctive purple-greyish hue observed during the synthesis can be related to the interaction of gold precursor with the growing gold nanoparticles.