The Y <sub> 2 </ Sub> O <sub> 3 </ Sub>: Eu (3 +) And Y <sub> 2 </ Sub> The O <sub> 2 </ Sub> S Nanophosphors Solvent Thermal Preparation And Luminescent Properties Of,

Rare-earth oxides and oxysulfides possess excellent physical and chemical properties such as high luminescence efficiency, high-temperature stability and high corrosion resistance, and have been widely used in transparent ceramics and luminescent devices such as FED and CRT, etc. Due to the unique physical and chemical properties resulting from nano-crystallites, rare-earth phosphors may have better luminescence properties, and therefore preparation of nanocrystalline rare-earth oxides and oxysulfides is a challenging and valuable research topic, which is also the main aim of this thesis.In this paper, Y₂O₃ nano-materials were prepared via solvothermal process and the luminescent properties of Y₂O₃:Eu³⁺ nano-phosphors were investigated. And based on such experiments, the synthesis of nano-Y₂O₂S was tried. The products were characterized by XRD, TEM, SEM, EDS, DTA-TG, FT-IR and PL spectra. The main contents are summarized as following.(1) An effective approach to prepare nano-Y₂O₃ and Y₂O₃:Eu³⁺ was demonstrated. The experiment parameters, such as solvothermal treatment temperature, time, solvent kinds and heat treatment condition, were investigated to clarify their effect on the properties of the products. The results show that ethylenediamine solvent plays a key role in the solvothermal system and the optimal preparation condition is as following: solvothermally treated at 300 ℃ for 3h and then calcined at 460 ℃ for 2h.(2) The obtained products were rice-like about 30nm in diameter, and had high purity and better sintering ability. Via solvothermal process, the Eu³⁺ can be uniformly doped into Y₂O₃ structure, and nano-Y₂O₃:Eu³⁺ phosphors show particle-size dependence for optical properties. Compared to the commercial micro-products, the peak of UV band excitation spectra of the resultant products was red-shifted;their peaks of emission spectra broaden and the relative intensities of the strongest ones, corresponding to the typical 4f transition ⁵D₀â†'⁷F₂, declined too. Nevertheless, the quenching concentration of Eu³⁺in nano- Y₂O₃:Eu³⁺ phosphors increased greatly.(3) The synthesis of nano-Y₂O₂S via solvothermal process was tried with differentsulf- and yttric reactants. The results showed that solvothermal preparation of nano-Y2C>2S was failed at present stage, such result may correspond to the tough conditions to obtain nano-Y2O2S because of the strong Y-0 bonds. Further researches should be taken in order to get the desired products effectively.