Passivation of CdSe Quantum Dots by Graphene and MoS2 Monolayer Encapsulation

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• 作者：Datong Zhang ; Dennis Zi-Ren Wang ; Richard Creswell ; Chenguang Lu ; Jonathan Liou ; Irving P. Herman
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：July 28, 2015
• 年：2015
• 卷：27
• 期：14
• 页码：5032-5039
• 全文大小：408K
• ISSN：1520-5002

文摘

The encapsulation of a monolayer of CdSe quantum dots (QDs) by one-to-three layer graphene and MoS₂ sheets protects the QDs from oxidation. Photoluminescence (PL) from the QD cores shows a much slower decrease in core diameter over time due to slower oxidation in regions where the QDs are covered by van der Waals (vdW) layers than in those where they are not, for chips stored both in the dark and in the presence of light. PL mapping shows that the CdSe QDs under the central part of the vdW sheet age slower than those near its edges, because oxidation of the covered QDs is limited by transport of oxygen from the edges of the vdW sheets and not transport across the vdW layers. The transport of oxygen to the covered QDs is analyzed by coupling the PL results and a model of QD core oxidation.