Shape Adjustment between Multiply Twinned and Single-Crystalline Polyhedral Gold Nanocrystals: Decahedra, Icosahedra, and Truncated Tetrahedra

详细信息    查看全文

• 作者：Daeha Seo ; Choong Il Yoo ; Im Sik Chung ; Seung Min Park ; Seol Ryu ; Hyunjoon Song
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：February 21, 2008
• 年：2008
• 卷：112
• 期：7
• 页码：2469 - 2475
• 全文大小：560K
• 年卷期：v.112,no.7(February 21, 2008)
• ISSN：1932-7455

文摘

Polyhedral gold nanocrystals with decahedral, icosahedral, and truncated tetrahedral shapes are synthesizedby a simple one-pot polyol process in the prescence of poly(vinyl pyrrolidone) (PVP). High PVP concentrationup to 360 equiv of the gold precursor, HAuCl₄, effectively stabilizes decahedral seeds to yield uniform decahedrawith various edge sizes. Decreased PVP concentration subsequently leads to selective formation of icosahedraand truncated tetrahedra. This results from a combination between the relative energy difference of thepolyhedral structures and the oxidative etching rate of the seeds by Cl^-/O₂ during the reaction. The distinctmorphologies of gold nanocrystals exhibit characteristic extinction patterns in the UV-vis-NIR ranges, andthese properties are successfully analyzed by the discrete dipole approximation (DDA) calculation. Mostextinctions stem from the polar and azimuthal dipolar excitations, and azimuthal quardrupole resonance appearsbetween two dipolar bands in the 88-nm decahedra. Given these shape- and size-dependent optical properties,gold nanocrystals hold considerable promise for biomedical and photonic applications.