Based On The Er < Sup > 3 + < / Sup > / Yb < Sup > 3 + < / Sup > / Tm < Sup > 3 + < / Sup > Codoping Gd < Sub > 2 < / Sub > O < Sub > 3 < / Sub > Empty Core Ball Luminescence Properties Research

The up-conversion luminescence of rare earth ion doped materials in phosphors, solarcells, bio-fluorescent labeling, color display as well as areas such as green lighting hasbroad application prospects. The nanometer hollow microsphere doped with rare earth ionsis one of the focuses in recent years on the upconversion of materials.In this thesis, we study the preparation and the conversion luminescence phenomenonand the mechanism of Gd₂O₃nano-hollow microsphere doping Er³⁺, Er³⁺/Yb³⁺, Tm³⁺/Yb³⁺and Er³⁺/Yb³⁺/Tm³⁺ions at room temperature. We with the Li⁺doped in the Er³⁺/Yb³⁺co-doped nano-materials the fluorescence intensity dramatically enhanced. We study theLi⁺ion affect the luminescence mechanism of Er³⁺and Yb³⁺ions.First of all, The samples of Er³⁺/Yb³⁺co-doped and Tm³⁺/Yb³⁺co-doped Gd₂O₃nanocrystalline materials with different concentration were prepared by HydrothermalSynthesis, respectively. Under980nm infrared laser excitation, we were measured theupconversion luminescence of Er³⁺ions, the light emission of green light peak is520nm（2H11/2â†'4I15/2） and550nm （4S3/2â†'4I15/2）, red light peak is668nm （4I9/2â†'4I15/2）.Upconversion luminescence of Tm³⁺ions, blue light peak is475nm （1G4â†'3H6）.According to the change of doping concentration ratio, found that the red, green, and bluelight shine light intensity can be adjusted. According to the analysis of the power curve andthe energy level matching conditions are given Er³⁺/Yb³⁺, Tm³⁺/Yb³⁺energy level diagramand explain the luminescence mechanism. The emissions of520nm,550nm and668nmwere mainly two-photon process. The emission of475nm was mainly three-photonprocess.Second, The samples of Er³⁺/Yb³⁺/Tm³⁺co-doped Gd₂O₃nano-hollow microspherematerials were prepared by Hydrothermal Synthesis. The crystal morphology of Gd₂O₃nanocrystals was confirmed by XRD and TEM in the samples. Under980nm laserexcitation, we were measured the upconversion luminescence of the samples, the lightemission of green light peak is520nmand550nm, red light peak is668nm, and blue light peak is475nm. Through the control doping concentration ratio, got the white light output.Finally, we study the Li⁺ion concentration affect the upconversion luminescence ofthe samples doping Er³⁺and Yb³⁺ions. The upconversion luminescence of red and greenlight were enhanced with the increase of the concentration of Li⁺ion. When the Li⁺ionconcentration of2mol%, the upconversion luminescence reaching the strongest. Weanalyzes the upconversion luminescence mechanism of Li⁺/Er³⁺/Yb³⁺co-doped Gd₂O₃system and found that the Er³⁺ions have the four-photon avalanche phenomenon wiht theexcitation of low-power.