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Oxalic Acid Enabled Emission Enhancement and Continuous Extraction of Chloride from Cesium Lead Chloride/Bromide Perovskite Nanocrystals
Author(s) -
Wang Shixun,
Shen Xinyu,
Zhang Yu,
Zhuang Xingwei,
Xue Dingke,
Zhang Xiangtong,
Wu Jinlei,
Zhu Jinyang,
Shi Zhifeng,
Kershaw Stephen V.,
Yu William W.,
Rogach Andrey L.
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201901828
Subject(s) - halide , oxalic acid , perovskite (structure) , photoluminescence , inorganic chemistry , bromide , nanocrystal , caesium , chloride , materials science , chemistry , nanotechnology , crystallography , organic chemistry , optoelectronics
All‐inorganic cesium lead halide perovskite nanocrystals (NCs) have demonstrated excellent optical properties and an encouraging potential for optoelectronic applications; however, mixed‐halide perovskites, especially CsPb(Cl/Br) 3 NCs, still show lower photoluminescence quantum yields (PL QY) than the corresponding single‐halide materials. Herein, anhydrous oxalic acid is used to post‐treat CsPb(Cl/Br) 3 NCs in order to initially remove surface defects and halide vacancies, and thus, to improve their PL QY from 11% to 89% for the emission of 451 nm. Furthermore, due to the continuous chelating reaction with the oxalate ion, chloride anions from the mixed‐halide CsPb(Cl/Br) 3 perovskite NCs could be extracted, and green emitting CsPbBr 3 NCs with PL QY of 85% at 511 nm emission are obtained. Besides being useful to improve the emission of CsPb(Cl/Br) 3 NCs, the oxalic acid treatment strategy introduced here provides a further tool to adjust the distribution of halide anions in mixed‐halide perovskites without using any halide additives.