College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Department of Physics, University of Cagliari, S.p. no. 8 Km0700, 09042 Monserrato (Ca), Italy.
Nano Lett. 2021 Apr 14;21(7):2919-2925. doi: 10.1021/acs.nanolett.0c05105. Epub 2021 Mar 25.
Symmetry-breaking synthetic controls allow for nanostructure geometries that are counter to the underlying crystal symmetry of a material. If suitably applied, such controls provide the means to drive an isotropic metal along a growth pathway yielding a three-dimensional chiral geometry. Herein, we present a light-driven solution-based synthesis yielding helical gold spirals from substrate-bound seeds. The devised growth mode relies on three separate symmetry-breaking events ushered in by seeds lined with planar defects, a capping agent that severely frustrates early stage growth, and the Coulombic repulsion that occurs when identically charged growth fronts collide. Together they combine to advance a growth pathway in which planar growth emanates from one side of the seed, advances to encircle the seed from both clockwise and counterclockwise directions, and then, upon collision of the two growth fronts, sees one front rise above the other to realize a self-perpetuating three-dimensional spiral structure.
对称破缺的合成控制允许出现与材料基础晶体对称性相反的纳米结构几何形状。如果应用得当，这些控制手段可以沿着生长路径驱动各向同性金属，从而产生三维手性几何形状。在此，我们提出了一种基于光驱动的溶液法，从基底结合的种子中得到螺旋状的金螺旋。所设计的生长模式依赖于三个独立的对称破缺事件，它们由带有平面缺陷的种子、严重阻碍早期生长的封端剂以及当相同电荷的生长前沿碰撞时发生的库仑斥力引入。它们共同结合，推进了一种生长途径，其中平面生长从种子的一侧开始，顺时针和逆时针方向同时环绕种子生长，然后，当两个生长前沿碰撞时，一个前沿上升到另一个前沿之上，实现了一个自我维持的三维螺旋结构。
