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Cesium Lead Chloride/bromide Perovskite Quantum Dots with Strong Blue Emission Realized via a Nitrate-Induced Selective Surface Defect Elimination Process.

Research paper by Shixun S Wang, Yu Y Wang, Yu Y Zhang, Xiangtong X Zhang, Xinyu X Shen, Xingwei X Zhuang, Po P Lu, William W WW Yu, Stephen V SV Kershaw, Andrey L AL Rogach

Indexed on: 20 Dec '18Published on: 20 Dec '18Published in: Journal of Physical Chemistry Letters



Abstract

Cesium lead halide perovskites emitting blue light in the range of wavelengths 460 to 470 nm have so far been plagued with rather poor luminescent performance, placing inevitable limitations on the development of perovskite nanocrystal-based blue light-emitting devices. Herein, a selective surface defect elimination process with the help of hydrated nitrates was introduced into the perovskite/toluene solution to strip the undesired surface defects and vacancies, and to boost the photoluminescence quantum yield of true-blue-light emitting (at 466 nm) CsPb(Cl/Br)3 perovskite nanocrystals to the impressive value of 85%. Unlike the conventional passivation strategy, the anionic nitrate ions are able to desorb the undesired surface metallic lead and combine with excess surface metal ions leaving perovskite quantum dots with better crystallinity and fewer surface defects.

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