The Upconversion Nanomatrials Based On Rare Earth Oxides:Synthesis And Investigation Their Porperties

3, CeO2as an important rare earth oxide, which applied in the area of catalysisi, sensor and so on owing to their unique properties. What’s more, the radius of La3+and Ce4+are closely to the Er3+and Yb3+, so the Er3+, Yb3+easily doped into the lattice of CeO2and La2O3. Hence, in this decades, Er3+, Yb3+co-doped CeO2and Er3+, Yb3+co-doped La2O3are widely used in the upconversion nanomaterials. In this paper, we investigated the relationship of upconversion luminescence intensities and calcination temperature, band gap and concentration of Er. Next, we synthesized nanorod and hollow nanosphere of CeO2upconversion nanomaterials. Finally, we designed a pH sensor based on hollow CeO2:Er/Yb nanosphere. The major work has been done as follows in this paper.(1) The precursor of La2O3:Er3+was synthesized by the microwave-assisted hydrothermal method, and then La2O3:Er3+upconversion nanoparticles were obtained by calcination precursor at600℃,700℃,800℃. In this paper, we investigated the fact of upconversion luminescence intensities of different concentration of Er3+and different calcination temperature by the XRD, Solid UV and XPS. The result exhibits that the smaller band gap and the more lattice oxygen are available to enhancing the upconversion luminescence intensities.(2) The CeO2:Er/Yb nanorods were synthesized by the solvethermal method, and the nanorods were charactersized by the XRD, SEM, HRTEM and upconversion luminescence. The result shows that under980nm excition, the CeO2:Er/Yb emited green emission and red one at the wavelength of520-550nm and620-660nm, respectively. And the green upconversion intensities and red one are increased, when the excited power enhanced.(3) The hollow CeO2:Er/Yb nanospheres were synthesized by the template method, and the size of hollow spheres are approximately100nm. Finally, we also designed a pH sensos based on hollow CeO2:Er/Yb nanospheres. The results as follows:The green emission intensities and red one of hollow CeO2:Er/Yb are reach maximum values when the concentration of Yb3+are4%and20%, respectively. The upconversion luminescence intensities have a linear relationship with the pH of BTB at the range of6-10.