Department of Energy and Materials Engineering, Dongguk University, Seoul, Republic of Korea.
College of Medicine, Inha University, Chungsuk Bldg., Seohae-Daero, Jung-Gu, Incheon 22332, Republic of Korea.
J Colloid Interface Sci. 2019 Apr 15;542:308-316. doi: 10.1016/j.jcis.2019.01.132. Epub 2019 Feb 7.
We report a one-pot seedless green method for the synthesis of gold-silver (AuAg) spiky branched nanostars, with gold (90%) being the major component. Here, the zwitterionic surfactant lauryl sulfobetaine (LSB) is employed in the synthesis of bimetallic nanostars. The concentration of LSB plays an important role in determining the shape of nano-objects. A minimum LSB concentration of 50 mM is required for the formation of spiky branched nanostars, the size of which is controlled by increasing the LSB concentration. Two distinct intense localized surface plasmon resonances in the near-infrared (NIR) and short-wavelength infrared ranges are observed. The molecular structure of LSB causes LSB molecules to assemble into spherical micelles that act as a soft template for the growth of the nano-objects. An analysis of the mechanisms behind the formation of the nanostars suggests that there is a rapid growth of spikes followed by the formation of a spherical core at the center. AuAg nanostars with evenly spaced spikes and low branching demonstrate great potential as efficient nanocatalysts, surface-enhanced Raman scattering-active substrates and for photothermal therapy, active in both the visible and NIR regions.
我们报告了一种一锅无种子绿色合成金-银（AuAg）刺状分支纳米星的方法，其中金（90%）是主要成分。在这里，两性离子表面活性剂月桂基磺基甜菜碱（LSB）被用于合成双金属纳米星。LSB 的浓度在确定纳米物体的形状方面起着重要作用。形成刺状分支纳米星需要 LSB 的最小浓度为 50 mM，其尺寸通过增加 LSB 浓度来控制。在近红外（NIR）和短波长红外范围内观察到两个明显的强局域表面等离子体共振。LSB 的分子结构导致 LSB 分子组装成球形胶束，充当纳米物体生长的软模板。对纳米星形成背后的机制进行分析表明，存在一个快速生长的刺，然后在中心形成一个球形核心。具有均匀间隔的刺和低分支的 AuAg 纳米星作为高效纳米催化剂、表面增强拉曼散射活性衬底和光热治疗剂具有很大的潜力，在可见和 NIR 区域均具有活性。
