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Delayed Photoluminescence and Modified Blinking Statistics in Alumina-Encapsulated Zero-Dimensional Inorganic Perovskite Nanocrystals
journal contribution
posted on 2019-10-18, 19:03 authored by Tianle Guo, Riya Bose, Xiaohe Zhou, Yuri N. Gartstein, Haoze Yang, Sunah Kwon, Moon J. Kim, Marat Lutfullin, Lutfan Sinatra, Issam Gereige, Ahmed Al-Saggaf, Osman M. Bakr, Omar F. Mohammed, Anton V. MalkoWe
demonstrate enhancement of the photoluminescence (PL) properties
of individual zero-dimensional (0D) Cs4PbBr6 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.