Qi Xin, Chen Zihao, Yan Tianyu, Fichthorn Kristen A
ACS Nano. 2019 Apr 23;13(4):4647-4656. doi: 10.1021/acsnano.9b00820. Epub 2019 Mar 19.
Five-fold twinned metal nanowires can be synthesized with high aspect ratios via solution-phase methods. The origins of their anisotropic growth, however, are poorly understood. We combine atomic-scale, mesoscale, and continuum theoretical methods to predict growth morphologies of Ag nanowires from seeds and to demonstrate that high aspect ratio nanowires can originate from anisotropic surface diffusion induced by the strained nanowire structure. Nanowire seeds are similar to Marks decahedra, with {111} "notches" that accelerate diffusion along the nanowire axis to facilitate one-dimensional growth. The strain distribution on the {111} facets induces heterogeneous atom aggregation and leads to atom trapping at the nanowire ends. We predict that decahedral Ag seeds can grow to become nanowires with aspect ratios in the experimental range. Our studies show that there is a complex interplay between atom deposition, diffusion, seed architecture, and nanowire aspect ratio that could be manipulated experimentally to achieve controlled nanowire syntheses.
通过溶液相法可以合成具有高纵横比的五次孪晶金属纳米线。然而，它们各向异性生长的起源却鲜为人知。我们结合原子尺度、介观尺度和连续介质理论方法来预测银纳米线从种子开始的生长形态，并证明高纵横比的纳米线可能起源于由应变纳米线结构引起的各向异性表面扩散。纳米线种子类似于马克斯十面体，具有{111}“缺口”，这些缺口加速了沿纳米线轴的扩散，以促进一维生长。{111}面上的应变分布会诱导异质原子聚集，并导致原子在纳米线末端被捕获。我们预测十面体银种子可以生长成为纵横比在实验范围内的纳米线。我们的研究表明，原子沉积、扩散、种子结构和纳米线纵横比之间存在复杂的相互作用，可通过实验操作来实现可控的纳米线合成。
