Seed-Mediated Synthesis of Gold Octahedra in High Purity and with Well-Controlled Sizes and Optical Properties

摘要

We report a facile method for the synthesis of uniform Au octahedra with well-controlled sizes and optical properties by seed-mediated growth. Starting from single-crystal seeds of Au spheres with a uniform size, we could reproducibly obtain Au octahedra with a narrow size distribution (<7 % in standard deviation) and in high purity (>90 %). Moreover, the edge lengths of these Au octahedra could be readily tuned in a controllable fashion from 16 to 77 nm by varying the amount of seeds, the concentration of HAuCl₄, or both. We have also investigated the effects of water and poly(vinyl pyrrolidone) (PVP) in the system, as well as the reaction temperature, on the evolution of octahedral shape.