Growth Behavior of Gold Nanorods Synthesized by the Seed-Mediated Method: Tracking of Reaction Progress by Time-Resolved X-ray Absorption Near-Edge Structure, Small-Angle X-ray Scattering, and Ultraviolet-Visible Spectroscopy
Growth Behavior of Gold Nanorods Synthesized by the Seed-Mediated Method: Tracking of Reaction Progress by Time-Resolved X-ray Absorption Near-Edge Structure, Small-Angle X-ray Scattering, and Ultraviolet-Visible Spectroscopy
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DOI：
10.1021/acs.jpcc.8b00016
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发表时间：
2018-04-12
影响因子：
3.7
通讯作者：
Hino, Kazuyuki
中科院分区：
文献类型：
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作者：
Hatakeyama, Yoshikiyo;Sasaki, Koh;Hino, Kazuyuki
金纳米棒是一种极具吸引力的重要纳米材料，具有广泛的应用前景。为了研究种子介导法生成gnr的形成过程，我们利用时间分辨x射线吸收近边结构（XANES）对长径比为2 （GNR2s）、4 （GNR4s）和6 （GNR6s）的gnr进行了生长跟踪。此外，对于GNR6s，通过小角度x射线散射和紫外可见光谱进行了额外的测量，反应时间长达20 000 s。GNR2s和GNR4s采用十六烷基三甲基溴化铵（CTAB）作为表面活性剂，GNR6s采用苄基二甲基十六烷基氯化铵（BDAC）和CTAB作为表面活性剂。使用的三种分析方法提供了一致和补偿的结果。结果发现，GNR2s和GNR4s在2000 s结束生长，消耗了溶液中的全部Au， GNR6s以不同的形成过程持续生长超过20000 s。从这些综合结果可以看出，在所有解中，gnr之间存在着激烈的生存竞争。添加到GNR2s和GNR4s溶液中的种子颗粒开始生长，但整个种子颗粒不能成熟为gnr。相反，在gnr6的溶液中，一些已经生长的gnr释放出Au原子，从而允许进一步的gnr生长，使形成过程缓慢，独特且复杂。在适当比例的CTAB和BDAC协调下，gnr6的生长持续超过20,000 s。特别是，通过使用时间分辨XANES跟踪生长溶液，首先观察到GNR6s的来回生长。
Gold nanorods (GNRs) are attractive and important nanomaterials that show enormous promise for a wide range of applications. To investigate the formation process of GNRs generated by the seed-mediated method, we tracked the growth of GNRs with aspect ratios of 2 (GNR2s), 4 (GNR4s), and 6 (GNR6s) using time resolved X-ray absorption near-edge structure (XANES). Moreover, for GNR6s, additional measurements by small-angle X-ray scattering and ultraviolet visible spectroscopy were carried out for longer reaction times of up to 20 000 s. Cetyltrimethylammonium bromide (CTAB) was used as the surfactant in the generation of GNR2s and GNR4s, whereas benzyldimethylhexadecylammonium chloride (BDAC) and CTAB were used for GNR6s. The three analysis methods used provided consistent and compensatory results. It was found that GNR2s and GNR4s finish growing by 2000 s, consuming all the Au in the solutions, and that GNR6s keeps growing for more than 20 000 s by a different formation process. From these comprehensive results, it was revealed that severe competition for existence among the GNRs occurs in all solutions. The seed particles added to the solutions of GNR2s and GNR4s start growing but the whole seed particles cannot mature into GNRs. Conversely, in the solution for GNR6s, some of the already-grown GNRs release Au atoms, allowing the growth of further GNRs, making the formation process slow, unique, and complex. The growth of GNR6s coordinated by CTAB and BDAC in appropriate proportions continues more than 20 000 s. In particular, back-and-forth growth of GNR6s is first observed by tracking the growth solution using time-resolved XANES.