Au329鈥?i>xAgx(SR)84 Nanomolecules: Plasmonic Alloy Faradaurate-329

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• 作者：Chanaka Kumara ; Xiaobing Zuo ; David A. Cullen ; Amala Dass
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：August 20, 2015
• 年：2015
• 卷：6
• 期：16
• 页码：3320-3326
• 全文大小：456K
• ISSN：1948-7185

文摘

Though significant progress has been made to improve the monodispersity of larger (>10 nm) alloy metal nanoparticles, there still exists a significant variation in nanoparticle composition, ranging from 卤1000s of atoms. Here, for the first time, we report the synthesis of atomically precise (卤0 metal atom variation) Au_329鈥?i>xAg_x(SCH₂CH₂Ph)₈₄ alloy nanomolecules. The composition was determined using high resolution electrospray ionization mass spectrometry. In contrast to larger (>10 nm) Au鈥揂g nanoparticles, the surface plasmon resonance (SPR) peak does not show a major shift, but a minor 鈭?0 nm red-shift, upon increasing silver content. The intensity of the SPR peak also varies in an intriguing manner, where a dampening is observed with medium silver incorporation, and a significant sharpening is observed upon higher Ag content. The report outlines (a) an unprecedented advance in nanoparticle mass spectrometry of high mass at atomic precision; and (b) the unexpected optical behavior of Au鈥揂g alloys in the region where nascent SPR emerges; specifically, in this work, the SPR-like peak does not show a major 鈭?00 nm blue-shift with Ag alloying of Au₃₂₉ nanomolecules, as shown to be common in larger nanoparticles.