Spontaneous transformation of polyelectrolyte-stabilized silver nanoprisms by interaction with thiocyanate.
Spontaneous transformation of polyelectrolyte-stabilized silver nanoprisms by interaction with thiocyanate.
复制标题
聚电解质稳定的银纳米棱柱与硫氰酸盐相互作用的自发转变
DOI：
10.1016/j.jcis.2012.11.026
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发表时间：
2013
影响因子：
9.9
通讯作者：
J.M. Köhler
中科院分区：
文献类型：
--
作者：
A. Knauer;N. Visaveliya;J.M. Köhler
硫氰酸钾与三角形银纳米颗粒的胶体溶液反应，导致了形状的转变。这种反应不能用简单的三角形角部蚀刻来解释，因为在早期关于纳米银与卤化物阴离子相互作用导致纳米盘形成的报道中描述了这一反应[1]。加入KSCN后的反应产物为尺寸分布均匀的球形银纳米粒子，在约410 nm处表现出典型的短波等离激元吸收。反应的光谱在线监测反映了一个相当均匀的转化过程。在某些情况下，已经观察到等色点，这表明初始粒子类型直接与最终粒子类型发生反应。转化过程的动力学更好地用分子转化来描述，而不是用物质的逐步输送导致颗粒形状的连续变化的过程来描述。实验结果提出了两步转化的机制：在第一步(缓慢)，粒子被阴离子聚电解质配体解吸而不稳定。然后，不稳定的粒子在(快速)第二步中迅速松弛成球形。这种解释似乎严重影响了对非球形纳米粒子的理解：水溶液中较大的三角形棱柱粒子由于与一个或几个配体分子的相互作用而被其特定的电子性质稳定，必须被理解为一个分子模拟动力学系统，而不是一个小的固态体。
The reaction of KSCN with colloidal solutions of triangular silver nanoprisms results in a shape transformation. The reaction cannot be explained by a simple etching of the corners of the triangles, as it is described in earlier reports on the interaction of silver nanoprisms with halide anions leading to the formation of nanodisks [1]. The reaction products after KSCN addition are spherical silver nanoparticles with a homogeneous size distribution, which display the typical short-wavelength plasmon absorption at about 410nm. The spectral online monitoring of the reaction reflects a rather homogeneous conversion process. In some cases, isosbestic points have been observed, indicating a reaction of the initial particle type directly to the final particle type. The kinetics of the conversion process are better described by a molecular conversion, than by a process with a step-wise transport of material leading to a continuous change in the particle shape. The experimental findings suggest a two-step mechanism for the conversion: In a first (slow) step the particle is destabilized by desorption of the anionic polyelectrolyte ligand. Then the destabilized particles relax quickly in a (fast) second step to a spherical shape. This interpretation seems to have a serious impact on the understanding of non-spherical nanoparticles in general: The comparatively large triangular shaped prismatic particles in aqueous solution are stabilized by their specific electronic properties due to the interaction with one or several ligand molecules and must be understood as a molecular-analog dynamic system than as a small solid-state body.
影响因子：
1.8
作者：
Hilger, A;Cüppers, N;Kreibig, U
通讯作者：
Kreibig, U
影响因子：
3
作者：
Frank, Andrew J.;Cathcart, Nicole;Kitaev, Vladimir
通讯作者：
Kitaev, Vladimir
影响因子：
3.7
作者：
Knauer, Andrea;Csaki, Andrea;Koehler, J. Michael
通讯作者：
Koehler, J. Michael