title: Solvothermal synthesis and upconversion properties of about 10 nm orthorhombic LuF₃: Yb³⁺, Er³⁺ rectangular nanocrystals.
abstract: The Yb(3+) and Er(3+) codoped orthorhombic LuF3 rectangular nanocrystals (NCs) with the size of about 10nm were synthesized by a facile and effective solvothermal process. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), upconversion (UC) luminescence spectra and decay curves were used to characterize the resulting samples. Compared with YF3 and α-NaYF4 NCs, owning the similar size and the same doping levels of Yb(3+) ions and Er(3+) ions as LuF3 NCs, the green UC emission of LuF3 NCs is 18.7 times and 5.1 times stronger than that of YF3 and α-NaYF4 NCs respectively; the red UC emission of LuF3 NCs is 13.2 times and 0.6 times stronger than that of YF3 and α-NaYF4 NCs respectively. Under 980 nm wavelength excitation, the decay curves of both (4)S3/2→(4)I15/2 transition and (4)F9/2→(4)I15/2 transition exhibit a single exponential function, resulting from the fast energy migrations among Yb(3+) ions caused by the high concentration of Yb(3+) ions (20 mol%). Meanwhile, at relatively low power density, the slopes of the linear plots between log(I) and log(P) for green UC and red UC are 1.7 and 1.9 respectively, which are less than 2 due to the quenching of the thermal effect, indicating a two-photon process for them. At high power density, the slopes are decreased caused by the saturation effect. In addition, we proved the existence of the thermal effect by the pump power dependence of the intensity ratio of (2)H11/2→(4)I15/2 transition to (4)S3/2→(4)I15/2 transition.
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China; Graduate School of Chinese Academy of Sciences, Beijing 100039, China.
authors: Guotao
authors: G
authors: Xiang
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China. Electronic address: zhangjh@ciomp.ac.cn.
authors: Jiahua
authors: J
authors: Zhang
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors: Zhendong
authors: Z
authors: Hao
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors: Xia
authors: X
authors: Zhang
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors: Guo-Hui
authors: GH
authors: Pan
authors: School of Basic Sciences, ChangChun University of Technology, A1018 Huguang Road, Changchun 130012, China.
authors: Li
authors: L
authors: Chen
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors: Yongshi
authors: Y
authors: Luo
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors: Shaozhe
authors: S
authors: Lü
authors: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors: Haifeng
authors: H
authors: Zhao
mesh_terms: D004871:Erbium / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D008187:Lutetium / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D008187:Lutetium; D004871:Erbium; D015018:Ytterbium; D005459:Fluorides
keywords: LuF(3); Solvothermal process; Thermal effect; Upconversion