Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.
ACS Nano. 2013 Jun 25;7(6):5084-90. doi: 10.1021/nn4017845. Epub 2013 May 21.
An all-inorganic compound colloidal quantum dot incorporating a highly emissive CdSe core, which is linked by a CdS tunneling barrier to an engineered charge carrier trap composed of PbS, is designed, and its optical properties are studied in detail at the single-particle level. Study of this structure enables a deeper understanding of the link between photoinduced charging and surface trapping of charge carriers and the phenomenon of quantum dot blinking. In the presence of the hole trap, a "gray" emissive state appears, associated with charging of the core. Rapid switching is observed between the "on" and the "gray" state, although the switching dynamics in and out of the dark "off" state remain unaffected. This result completes the links in the causality chain connecting charge carrier trapping, charging of QDs, and the appearance of a "gray" emission state.
设计了一种全无机复合胶体量子点，其中包含一个高辐射的 CdSe 核，通过 CdS 隧道势垒与由 PbS 组成的工程化电荷载流子陷阱相连，并在单粒子水平上对其光学性质进行了详细研究。对这种结构的研究使我们能够更深入地了解光致充电和表面俘获电荷载流子之间的联系，以及量子点闪烁现象。在空穴陷阱存在的情况下，出现了一个“灰色”发射状态，与核心的充电有关。尽管在黑暗的“关闭”状态下的开关动力学仍然不受影响，但可以观察到在“开”和“灰色”状态之间的快速切换。这个结果完成了连接电荷载流子俘获、QD 充电和“灰色”发射状态出现的因果链中的环节。
