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Controlled Growth and Up‐Conversion Improvement of Sodium Yttrium Fluoride Crystals
Author(s) -
Fu Junxiang,
Fu Xionghui,
Wang Chaomin,
Yang Xianfeng,
Zhuang Jianle,
Zhang Gongguo,
Lai Boyuan,
Wu Mingmei,
Wang Jing
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201201278
Subject(s) - chemistry , yttrium , sodium , ion , sodium fluoride , photoluminescence , fluoride , aqueous solution , inorganic chemistry , hexagonal crystal system , crystal structure , crystal (programming language) , crystallography , materials science , optoelectronics , organic chemistry , computer science , programming language , oxide
A variety of hexagonal sodium yttrium fluoride (NYF) crystals with tunable shapes have been grown, and their up‐conversion (UC) emission has been greatly improved after post‐treatment in an aqueous solution of NH 4 HF 2 and NaF. The enhancement has been attributed to topotactic ion insertion of sodium cations into the channels of Na 3 x Y 2– x F 6 . As sodium‐ion insertion continues to occur and the sodium content rises, the up‐conversion emission intensity and green‐to‐red ratio increase up to the saturation level. However, the X‐ray diffraction patterns and SEM images suggest that both the crystallographic structure and geometric morphology remain unchanged during this topotactic sodium ion insertion. This strategy is very different to previous reports on the use of ion exchange in the preparation of sodium yttrium fluoride crystals and improvement of UC emission. The results of this work demonstrate that sodium vacancy in the hexagonal Na 3 x Y 2– x F 6 crystal is the key to the clear reduction in the up‐conversion photoluminescence properties of the crystals, but the topotactic sodium ion insertion can revive the up‐conversion efficiency greatly.