Guo Tianle, Bose Riya, Zhou Xiaohe, Gartstein Yuri N, Yang Haoze, Kwon Sunah, Kim Moon J, Lutfullin Marat, Sinatra Lutfan, Gereige Issam, Al-Saggaf Ahmed, Bakr Osman M, Mohammed Omar F, Malko Anton V
Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology , Thuwal 23955-6900 , Kingdom of Saudi Arabia.
Quantum Solutions LLC , Thuwal 23955-6900 , Kingdom of Saudi Arabia.
J Phys Chem Lett. 2019 Nov 7;10(21):6780-6787. doi: 10.1021/acs.jpclett.9b02594. Epub 2019 Oct 21.
We demonstrate enhancement of the photoluminescence (PL) properties of individual zero-dimensional (0D) CsPbBr perovskite nanocrystals (PNCs) upon encapsulation by alumina using an appropriately modified atomic layer deposition method. In addition to the increased PL intensity and improved long-term stability of encapsulated PNCs, our single-particle studies reveal substantial changes in the PL blinking statistics and the persistent appearance of the long-lived, "delayed" PL components. The blinking patterns exhibit a modification from the fast switching between fluorescent ON and OFF states found in bare PNCs to a behavior with longer ON states and more isolated OFF states in alumina-encapsulated PNCs. Controlled exposure of 0D nanocrystals to moisture suggests that the observed PL lifetime changes may be related to water-induced "reservoir" states that allow for longer-lived charge storage with subsequent back-feeding into the emissive states. Viable encapsulation of PNCs with metal oxides that can preserve and even enhance their PL properties can be utilized in the fabrication of extended structures on their basis for optoelectronic and photonic applications.
我们展示了通过使用适当改进的原子层沉积方法，用氧化铝封装单个零维（0D）CsPbBr钙钛矿纳米晶体（PNCs）后，其光致发光（PL）特性得到增强。除了封装后的PNCs的PL强度增加和长期稳定性提高外，我们的单粒子研究还揭示了PL闪烁统计的显著变化以及长寿命“延迟”PL成分的持续出现。闪烁模式从裸PNCs中发现的荧光开和关状态之间的快速切换转变为氧化铝封装的PNCs中开状态更长且关状态更孤立的行为。对0D纳米晶体进行可控的湿气暴露表明，观察到的PL寿命变化可能与水诱导的“储库”状态有关，这种状态允许更长寿命的电荷存储，随后再反馈到发射状态。用能够保留甚至增强其PL特性的金属氧化物对PNCs进行可行的封装，可用于基于它们制造用于光电和光子应用的扩展结构。
