Synthesis And Upconversion Luminescence Properties Of Rare-earth Doped TiO₂ Nanocrystal

Nano-sized upconversion luminescence material has enormous potential application in many new areas, large values of explotation and application not only because it has unique physical and chemical properties that are different from those of bulk materials unique luminescence properties of upconversion. Therefore, the research of experiment and theory of nano-sized upconversion luminescence materials has become one of the hotspots in the research fields of advanced materials nowadays. This paper mainly researched on the synthesis and luminescence property of TiO₂:Yb³⁺, Er³⁺ and Li⁺ doped TiO₂:Yb³⁺, Ho³⁺ nano-crystal. The main contents are as following:1. TiO₂:Yb³⁺, Er³⁺ nano-sized up-conversion phosphors were prepared by hydrolysis- precipitation method. The green (526nm, 547nm) and red (659nm) emission have been observed under the excitation of 980nm LD. The influences of Er³⁺ concentration and heat-treat temperature on upconversion luminescence are discussed. The upconversion luminescence intensities dependence on pump power confirmed that both green and red emission are two-photon absorption processes. The red and green emission gradually increase with the increase of pump power. However, relative intensity ratio of red emission and green emission gradually decreases with the increase of pump power.2. The Li⁺ doped TiO₂: Yb³⁺, Ho³⁺ nano-sized upconversion phosphors were prepared by hydrolysis-precipitation method. The influences of Yb³⁺, Ho³⁺, Li⁺ doping concentration and heat-treat temperature on luminescence are discussed. Furthermore, the influences of Li⁺ doping on structure, morphology and up-conversion luminescence property of nano-particles are investigated by using X-ray diffraction (XRD), transmission electronic microscope (TEM) and photoluminescence spectra (PL). The analyzed results indicate that Li⁺ doping increases the particle size, makes the morphology better with ellipsoidal shape and enhances the crystallization remarkably. Particularly, the up-conversion luminescence intensity is enhanced remarkably after Li⁺...