title: Magnetic and upconverted luminescent properties of multifunctional lanthanide doped cubic KGdF4 nanocrystals.
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.
authors.affiliation: Institute for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105, China. ylwxtu@xtu.edu.cn
authors.forename: L W
authors.initials: LW
authors.lastname: Yang
authors.forename: Y Y
authors.initials: YY
authors.lastname: Zhang
authors.forename: J J
authors.initials: JJ
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: J X
authors.initials: JX
authors.lastname: Zhong
authors.forename: Paul K
authors.initials: PK
authors.lastname: Chu
mesh_terms: D005682:Gadolinium / Q000737:chemistry; D006695:Holmium / Q000737:chemistry; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D013932:Thulium / Q000737:chemistry; D014961:X-Ray Diffraction; D015018:Ytterbium / Q000737:chemistry
chemical_list: D028581:Lanthanoid Series Elements; D013932:Thulium; D005682:Gadolinium; D015018:Ytterbium; D006695:Holmium