2-14IonicLiquidDendriticGoldNanostructures.pdfVIP

Chem. Mater. 2008, 20, 3965–3972 3965 Ionic Liquid-Assisted Growth of Single-Crystalline Dendritic Gold Nanostructures with a Three-Fold Symmetry Yao Qin, Yin Song, Nijuan Sun, Nana Zhao, Meixian Li, and Limin Qi* Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry, Peking UniVersity, Beijing 100871, People’s Republic of China Recei Ved January 24, 2008. ReVised Manuscript ReceiVed April 23, 2008 Hierarchical, three-fold symmetrical, single-crystalline gold dendrites were synthesized by the reaction between a zinc plate and a solution of HAuCl in the ionic liquid [BMIM][PF ]. The unique dendritic 4 6 gold nanostructures show a three-order hierarchy (i.e., a three-fold symmetrical 111-oriented trunk, three groups of trident-like 111-oriented branches grown on the trunk, and many 111-oriented nanorod leaves grown on the branches symmetrically), indicating an interesting fractal growth. According to the investigation on the growth process of the gold dendrites, it was proposed that gold nuclei nanocrystals first formed on the zinc substrate through a direct surface reaction and that the subsequent crystal growth preferentially took place on the preformed gold crystals through a primary cell reaction, leading to the formation of the final hyperbranched den