The Er And Yb Co-Doped Upconversion Nanomaterials Based On Rare Earth Oxides: Synthesis And Investigation Their Porperties

Upconversion nano materials have been investigated extensively due to the potential applications in biological imaging, metal ions detection, medical treatment and various of other fields. The Yb3+, Er3+ co-doped CeO2 and Yb3+, Er3+ co-doped La2O3 are important upconversion nano materials based on oxides because of their stable physical and chemical properties and lower phonon energy. So in this thesis, three kinds of Yb3+, Er3+ co-doped upconversion nanomaterials based on rare earth oxides have been synthesized and their upconversion fluorescence properties have been studied. Then, the possibility of CeO2:Er/Yb@SiO2:RBH applied to the detection of Cu2+ has been discussed. The main contents are summarized as follows:Synthesis and upconversion fluorescence properties of CeO2:Er/Yb nano octahedron. CeO2 nano-octahedra co-doped with Er3+ and Yb3+ were successfully synthesized by a simple hydrothermal synthesis method. Meanwhile, the relationship of upconversion fluorescence properties with the doped concentration of Yb3+, the calcining temperature, and the species of oxygen was been discussed. The luminescence process of CeO2:Er/Yb nano crystal with 980 nm near infrared light was investigated. The researches show that a suitable doped concentration of Yb3+, higher calcination temperature and surface adsorption oxygen are conductive to upconversion fluorescence.CeO2:Er/Yb nano particles were synthesized by the solvothermal method, and the CeO2:Er/Yb@SiO2:RBH has been designed for the detection of Cu2+ in environment. The result exhibits that the upconversion luminescence intensities ratio of I546 nm and I658 nm have a linear function relationship with the concentration of Cu2+ in the range of 0-50 uM.3DOM La2O3: Er/Yb were synthesized by the citric acid combustion method with PMMA as a template, and the 3DOM La2O3: Er/Yb were characterized by the SEM, TEM, XRD, and upconversion luminescence spectrum. The studies show that under 980 nm near infrared light excitation, the 3DOM La2O3: Er/Yb emited green emission and red emission at the wavelength of 520-560 nm and 650-675 nm, respectively. In addition, the intensities of red emission is higher than the green one. Along with the excited power enhanced, both red and green emission were increased.