Researchers Discover Novel Route for Synthesis of Ultrasmooth Gold Nanospheres (Material Science)

Recently, a research team led by Prof. LI Yue from the Institute of solid State Physics of the Hefei Institutes of Physical Science (HFIPS), together with Prof. LI Cuncheng from the University of Jinan, developed a one-pot synthesis of ultrasmooth, precisely shaped gold nanospheres via surface self-polishing etching and regrowth.

Gold nanocrystals (Au NCs) has unique size- and shape-dependent optical properties. Scientists usually explore their properties via a controlled synthesis of Au NCs to achieve practical applications, but one-pot synthesis of Au nanospheres with perfect morphology remains a challenge as NCs tends to adopt a polyhedral morphology to minimize their surface free energy.

In this study, the team successfully demonstrated a synthesis for precisely shaped and monodispersed single-crystalline Au nanospheres. “The ultrasmooth surface and tunable sizes range from 30 nm to 100 nm.” said Prof. LI Yue.

Schematic of the Formation Mechanism of Au NSsa (Image by ZHANG Tao)

Through selectively surface self-polishing etching by the O2/Cl- pairs and Ag ions dynamically directed regrowth, Au NCs underwent a unique morphology change from octahedral to spherical shape.

They found the localized surface plasmon resonance property of Au nanospheres with different sizes was in line with the theoretical prediction because of their perfect spherical shapes and uniform sizes.

Moreover, as a result of the isotropic surface tension, this protocol can achieve a large-scale synthesis with more than 500 ml for one time of Au nanospheres solution with extreme stability.

The findings opened up unique insights into the formation mechanism of Au nanospheres with precisely controlled size and shape, and offered a promising way to the synthesis of other nanospheres.

This work was financially supported by the National Science Fund for Distinguished Young Scholars and the Natural Science Foundation of China.

Featured image: Synthesis scheme, morphology, and structure characterizations of Au NSs. (Image by ZHANG Tao)

Reference: Tao Zhang, Xuejiao Li, Cuncheng Li, Weiping Cai, and Yue Li, “One-Pot Synthesis of Ultrasmooth, Precisely Shaped Gold Nanospheres via Surface Self-Polishing Etching and Regrowth”, Chem. Mater. 2021.

Provided by Chinese Academy of Sciences

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