Unusual Selectivity of Metal Deposition on Tapered Semiconductor Nanostructures

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• 作者：Nimai Mishra ; Jie Lian ; Sabyasachi Chakrabortty ; Ming Lin ; Yinthai Chan
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：June 12, 2012
• 年：2012
• 卷：24
• 期：11
• 页码：2040-2046
• 全文大小：456K
• 年卷期：v.24,no.11(June 12, 2012)
• ISSN：1520-5002

文摘

We describe a surfactant-driven method to synthesize highly monodisperse CdSe-seeded CdS nanoheterostructures with conelike, tapered geometries in order to examine the effects of shape on the location-specific deposition of Au under ambient conditions. Although preferential metal deposition at surface defect sites are generally expected, we found suprisingly that Au growth at the side facets of tapered linear and branched structures was significantly suppressed. Further investigation revealed this to be due to a highly efficient electrochemical Ostwald ripening process which was previously thought not to occur in branched nanostructures such as tetrapods. We exploited this phenomenon to fabricate uniform asymmetrically tipped CdSe-seeded CdS tetrapods with conelike arms, where a solitary large Au tip is found on one of the arms while the other three arms bear Ag₂S tips. Importantly, this work presents a synthetic route toward the selective deposition of metals onto branched semiconductor nanostructures whose arms have nearly symmetric reactivity.

Keywords:

nanorods; tetrapods; metal-semiconductor; Ostwald ripening ; gold