Balancing Electron Transfer and Surface Passivation in Gradient CdSe/ZnS Core鈥揝hell Quantum Dots Attached to ZnO

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• 作者：Mohamed Abdellah ; Karel 沤铆dek ; Kaibo Zheng ; Pavel Ch谩bera ; Maria E. Messing ; T玫nu Pullerits
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2013
• 出版时间：June 6, 2013
• 年：2013
• 卷：4
• 期：11
• 页码：1760-1765
• 全文大小：341K
• 年卷期：v.4,no.11(June 6, 2013)
• ISSN：1948-7185

文摘

Core鈥搒hell (CS) quantum dots (QDs) are promising light absorbers for solar cell applications mainly because of their enhanced photostability compared with bare QDs. Moreover, the superb photostability can be combined with a low number of defects by using CSQDs with a gradient composition change from the core to the shell. Here, we study electron injection from the gradient CSQDs to ZnO nanoparticles. We observe the typical exponential injection rate dependence on the shell thickness (尾 = 0.51 脜^鈥?) and discuss it in light of previously published results on step-like CSQDs. Despite the rapid drop in injection rates with shell thickness, we find that there exists an optimum thickness of the shell layer at 1 nm, which combines high injection efficiency (>90%) with a superior passivation of QDs.

Keywords:

core鈭抯hell quantum dots; electron injection efficiency; ultrafast transient absorption; quantum yield; ZnO nanoparticles