The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States.
ACS Nano. 2013 May 28;7(5):4586-94. doi: 10.1021/nn401363e. Epub 2013 Apr 30.
Silver octahedra with edge lengths controlled in the range of 20-72 nm were synthesized via seed-mediated growth. The key to the success of this synthesis is the use of single-crystal Ag seeds with uniform and precisely controlled sizes to direct the growth and the use of citrate as a selective capping agent for the {111} facets. Our mechanistic studies demonstrated that Ag seeds with both cubic and quasi-spherical shapes could evolve into octahedra. For the first time, we were able to precisely control the edge lengths of Ag octahedra below 100 nm, and the lower limit of size could even be pushed down to 20 nm. Using the as-obtained Ag octahedra as sacrificial templates, Au nanocages with an octahedral shape and precisely tunable optical properties were synthesized through a galvanic replacement reaction. Such hollow nanostructures are promising candidates for a broad range of applications related to optics, catalysis, and biomedicine.
通过种子介导生长合成了边长在 20-72nm 范围内可控的银八面体。该合成的成功关键在于使用具有均匀且精确控制尺寸的单晶 Ag 种子来指导生长，并使用柠檬酸作为 {111} 面的选择性封端剂。我们的机理研究表明，具有立方和类球形的 Ag 种子都可以演变成八面体。我们首次能够精确控制小于 100nm 的 Ag 八面体的边长，尺寸的下限甚至可以推至 20nm。利用所获得的 Ag 八面体作为牺牲模板，通过电置换反应合成了具有八面体形貌和精确可调光学性质的 Au 纳米笼。这种中空纳米结构有望在与光学、催化和生物医学相关的广泛应用中得到应用。
