Transition to cubic phase and enhancement of green upconversion emission by adding La3+ ions in hexagonal NaLuF4:Yb3+/Er3+ nanocrystals

	Transition to cubic phase and enhancement of green upconversion emission by adding La3+ ions in hexagonal NaLuF4:Yb3+/Er3+ nanocrystals
	Xiang G. T.; Zhang J. H.; Hao Z. D.; Zhang X.; Luo Y. S.; Lu S. Z.; Zhao H. F.
	2014
发表期刊	Crystengcomm
ISSN	ISBN/1466-8033
卷号	16 期号:12 页码:2499-2507
摘要	Phase transition from hexagonal to cubic was successfully achieved through La3+ ions tridoping in NaLuF4:Yb3+/Er3+ nanocrystals (NCs) by a solvothermal process at 300 degrees C. X-Ray diffraction (XRD) patterns, scanning electron microscopy (SEM) images, transmission electron microscopy (TEM) images, Fourier-transform infrared (FTIR) absorption spectra, upconversion (UC) luminescence spectra and decay curves were used to characterize the resulting samples. Compared to cubic phase alpha-NaLu0.78Yb0.2Er0.02F4 NCs which are similar in size and prepared at normal temperature (280 degrees C), the number of the surface organic groups such as hydroxyl group (-OH) attached on NaLu0.48La0.3Yb0.2Er0.02F4 NCs is reduced. Furthermore, the green UC emission increases and simultaneously the red UC emission decreases. The UC mechanisms were studied by power-intensity log dependence. It indicates that in both of the two samples, the red UC emission is a two-photon process when the excitation power density is low, but a three-photon process occurs when the excitation power density is high. However, the green UC emission is a two-photon process all the time both at low or high excitation power density. Through analyzing the luminescence decay curves of the S-4(3/2) -> I-4(15/2) transition and F-4(9/2) -> I-4(15/2) transition under the 980 nm excitation wavelength, it is concluded that the population of the F-4(9/2) level originates from the I-4(13/2) level, not from the H-2(11/2)/S-4(3/2) level in the two samples.
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/44481
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	Xiang G. T.,Zhang J. H.,Hao Z. D.,et al. Transition to cubic phase and enhancement of green upconversion emission by adding La3+ ions in hexagonal NaLuF4:Yb3+/Er3+ nanocrystals[J]. Crystengcomm,2014,16(12):2499-2507.
APA	Xiang G. T..,Zhang J. H..,Hao Z. D..,Zhang X..,Luo Y. S..,...&Zhao H. F..(2014).Transition to cubic phase and enhancement of green upconversion emission by adding La3+ ions in hexagonal NaLuF4:Yb3+/Er3+ nanocrystals.Crystengcomm,16(12),2499-2507.
MLA	Xiang G. T.,et al."Transition to cubic phase and enhancement of green upconversion emission by adding La3+ ions in hexagonal NaLuF4:Yb3+/Er3+ nanocrystals".Crystengcomm 16.12(2014):2499-2507.

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