Ultrafast Emission Decay and Enhancement of Blinking of Single Quantum Dots in the Presence of Silicon and Metal/Metal Oxide Structures

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• 作者：Waylin J. Wing ; Seyed M. Sadeghi
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 12, 2017
• 年：2017
• 卷：121
• 期：1
• 页码：931-939
• 全文大小：604K
• ISSN：1932-7455

文摘

We experimentally investigate the impact of concentration of colloidal quantum dots on their lifetime and blinking dynamics when they are situated near material layers consisting of gold, aluminum oxide, and amorphous silicon combinations. Our results show that in the presence of the silicon layer the gold not only does not suppress the blinking behavior but rather promotes it at much higher concentrations of the quantum dots. This process happens as the emission decay rate of the quantum dots is increased significantly. For an amorphous silicon thickness of ∼5 nm, single quantum dots near the specific combination of gold/amorphous silicon/aluminum oxide layers exhibit mostly bright state behavior. However, when the thickness of the amorphous silicon is increased, we find that the single quantum dots remain mostly in the dark state. The work presented here highlights the profound impact of defect sites in amorphous silicon on the interplay between plasmon field enhancement and Auger recombination. The results can be used to modify and exploit desirable characteristics in the photoluminescent dynamics of colloidal quantum dots.