Rare Earth Doped NaYF₄ Nanocrystalline Preparation And Up-Conversion Emission Property

Up-conversion luminescence materials mainly is mixed of rare-earth element solid compounds, ree characteristics of metastable level, it can absorb multiple low-energy longwave radiation, through the photon to add and issued after the high-energy shortwave radiation, which can make the person see not the infrared into visible light. Fluoride has high luminous efficiency as upxonverted luminescence materials because its great forbidden band width, short wavelength of short-wave side absorb edge, lack phonons energy, and long infrared absorption boundary wavelength. Therefore fluoride matrix materials are concerned by researchers, especially the six-party phase NaYF₄ which is the most effective upxonverted nanometer materials that is currently found. This article investigates the influence of nanocrystalline structure with the drying temperature, drying time, and the amount of Y₂O₃. In this study, with NaYF₄ as the upxonverted matrix materials,the luminescence properties of the rare earth doped NaYF₄ that is stimulated by the 980nm laser are discussed, and the influence of upxonverted luminescence with the variation of doping rare earth elements and Ho³⁺ ions concentration is researched, and the influence of NaYF₄: Ho³⁺/Yb³⁺ and NaYF₄:Ho³⁺/Yb³⁺/Er³⁺ with 8-hydroxyquinoline doped is also researched.We prepared the up-conversion luminescence nanocrystalline to NaYF₄ for matrix.Up-conversion luminescence nanocrystalline pure NaYF₄, NaYF₄:Ho³⁺/Yb³⁺, NaYF₄:Yb³⁺/Ho³⁺/Er³⁺ nanocrystalline was prepared by hydrothermal method, and prepared NaYF₄:Ho³⁺/Yb³⁺, NaYF₄:Yb³⁺/Ho³⁺/Er³⁺ of complexing template reagent 8-hydroxyquinoline.The pure NaYF₄, NaYF₄:Ho³⁺/Yb³⁺, NaYF₄:Yb³⁺/Ho³⁺/Er³⁺ nanocrystalline were characterized by using of X-ray diffraction (XRD), Energy spectrum analysis, Scanning electron microscopy, transmission electron microscope (TEM). The results is that pure NaYF₄ nanocrystalline grain are mostly particle size larger diameter approximately spherical, 80nm, reunion phenomenon, as the time extending, drying of prismatic product to increase gradually. In NaYF₄:Ho³⁺/Yb³⁺ samples can significantly observed many in diameter, and pure 50nm particles NaYF₄ compare, very small particles, particle size is evener, sample particles morphology is spherical shape or ellipsoid. The up-conversion spectrum was measured by spectrohphotometer, under 980nm diode laser excitation, maximum output power 500mW, the results showed that: in NaYF₄:Ho³⁺/Yb³⁺ samples upxonverted fluorescence spectrum was obsered in 648nm 543nm green, red and green light and the intensity is about three times the strength of red. In NaYF₄:Ho³⁺/Yb³⁺/Er³⁺ samples upxonverted fluorescence spectrum was obsered in 662nm 543nm green, red and green light and the intensity is about 1.5 times. In NaYF₄: add 8-hydroxyquinoline NaYF₄:Ho³⁺/Yb³⁺ and NaYF₄:Ho³⁺/Yb³⁺/Er³⁺ samples upxonverted fluorescence spectrum in observing, template reagent to green without the influence, can make the red wavelengths movement.