Size- and Shape-Controlled Synthesis and Properties of Magnetic–Plasmonic Core–Shell Nanoparticles

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• 作者：Elyahb Allie Kwizera ; Elise Chaffin ; Xiao Shen ; Jingyi Chen ; Qiang Zou ; Zhiming Wu ; Zheng Gai ; Saheel Bhana ; Ryan O’Connor ; Lijia Wang ; Hitesh Adhikari ; Sanjay R. Mishra ; Yongmei Wang ; Xiaohua Huang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 19, 2016
• 年：2016
• 卷：120
• 期：19
• 页码：10530-10546
• 全文大小：1124K
• 年卷期：0
• ISSN：1932-7455

文摘

Magnetic–plasmonic core–shell nanomaterials offer a wide range of applications across science, engineering, and biomedical disciplines. However, the ability to synthesize and understand magnetic–plasmonic core–shell nanoparticles with tunable sizes and shapes remains very limited. This work reports experimental and computational studies on the synthesis and properties of iron oxide–gold core–shell nanoparticles of three different shapes (sphere, popcorn, and star) with controllable sizes (70 to 250 nm). The nanoparticles were synthesized via a seed-mediated growth method in which newly formed gold atoms were added onto gold-seeded iron oxide octahedrons to form a gold shell. The evolution of the shell into different shapes was found to occur after the coalescence of gold seeds, which was achieved by controlling the amount of additive (silver nitrate) and reducing agent (ascorbic acid) in the growth solution. First-principles calculation, together with experimental results, elucidated the intimate roles of thermodynamic and kinetic parameters in the shape-controlled synthesis. Both discrete dipole approximation calculation and experimental results showed that the nanopopcorns and nanostars exhibited red-shifted plasmon resonance compared with the nanospheres, with the nanostars giving multispectral feature. This research has made a great step further in manipulating and understanding magnetic–plasmonic hybrid nanostructures and will make an important impact in many different fields.