Enhanced Organo-Metal Halide Perovskite Photoluminescence from Nanosized Defect-Free Crystallites and Emitting Sites

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• 作者：Yuxi Tian ; Aboma Merdasa ; Eva Unger ; Mohamed Abdellah ; Kaibo Zheng ; Sarah McKibbin ; Anders Mikkelsen ; T玫nu Pullerits ; Arkady Yartsev ; Villy Sundstr枚m ; Ivan G. Scheblykin
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：October 15, 2015
• 年：2015
• 卷：6
• 期：20
• 页码：4171-4177
• 全文大小：392K
• ISSN：1948-7185

文摘

Photoluminescence (PL) of organo-metal halide perovskite semiconductors can be enhanced by several orders of magnitude by exposure to visible light. We applied PL microscopy and super-resolution optical imaging to investigate this phenomenon with spatial resolution better than 10 nm using films of CH₃NH₃PbI₃ prepared by the equimolar solution-deposition method, resulting in crystals of different sizes. We found that PL of 鈭?00 nm crystals enhances much faster than that of larger, micrometer-sized ones. This crystal-size dependence of the photochemical light passivation of charge traps responsible for PL quenching allowed us to conclude that traps are present in the entire crystal volume rather than at the surface only. Because of this effect, 鈥渄ark鈥?micrometer-sized perovskite crystals can be converted into highly luminescent smaller ones just by mechanical grinding. Super-resolution optical imaging shows spatial inhomogeneity of the PL intensity within perovskite crystals and the existence of <100 nm-sized localized emitting sites. The possible origin of these sites is discussed.