Magnetic and upconverted luminescent properties of multifunctional lanthanide doped cubic KGdF4 nanocrystals

L. W. Yang; Y. Y. Zhang; J. J. Li; Y. Li; J. X. Zhong; Paul K. Chu

doi:10.1039/C0NR00326C

Magnetic and upconverted luminescent properties of multifunctional lanthanide doped cubic KGdF₄nanocrystals

L. W. Yang,*^ab Y. Y. Zhang,^a J. J. Li,^a Y. Li,^a J. X. Zhong^a and Paul K. Chu*^b

* Corresponding authors

^a Institute for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, China
E-mail: ylwxtu@xtu.edu.cn, paul.chu@cityu.edu.hk

^b Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China

Abstract

Lanthanide (Ln³⁺) doped KGdF₄ (Ln = Yb³⁺, Er³⁺, Ho³⁺, Tm³⁺) nanocrystals with a mean diameter of approximately 12 nm were synthesized by a hydrothermal method using oleic acid as a stabilizing agent at 180 °C. The nanocrystals crystallize in the cubic phase as α-NaGdF₄. When excited by a 980 nm laser, these Ln³⁺ doped nanocrystals exhibit multicolor up-conversion (UC) emissions in red, yellow, blue and white. The calculated color coordinates demonstrate that white UC emission (CIE-X = 0.352, CIE-Y = 0.347) can be obtained by varying the dopant concentrations in the Yb³⁺/Ho³⁺/Tm³⁺ triply-doped nanocrystals to yield different RGB emission intensities. The measured field dependence of magnetization (M-H curves) of the KGdF₄ nanocrystals shows their paramagnetic characteristics that can be ascribed to the non-interacting localized nature of the magnetic moment of Gd³⁺ ions. Moreover, low temperature thermal treatment can enhance UC properties, magnetization and magnetic mass susceptibility of Ln³⁺ doped KGdF₄ nanocrystals. The multifunctional Ln³⁺ doped KGdF₄ nanocrystals have potential applications in color displays, bioseparation, and optical–magnetic dual modal nanoprobes in biomedical imaging.

Article information

https://doi.org/10.1039/C0NR00326C

Article type

Paper

Submitted

14 May 2010

Accepted

17 Jul 2010

First published

28 Sep 2010

Download Citation

Nanoscale, 2010,2, 2805-2810

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Magnetic and upconverted luminescent properties of multifunctional lanthanide doped cubic KGdF₄ nanocrystals

L. W. Yang, Y. Y. Zhang, J. J. Li, Y. Li, J. X. Zhong and P. K. Chu, Nanoscale, 2010, 2, 2805 DOI: 10.1039/C0NR00326C

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