Preparation And Characterization Of The Rare Earth Doped NaY_xGd_1-xF₄Nanorods

In recent years, rare earth doped up-conversion optical materials have beenextensively studied owing to their potential applications in infrared detection,3Ddisplay, undersea communication,biology labe and so on. Fluorides become excellenthost materials for lurninescence materials owing to their diversity structural features,special physical and chemical characteristic. Rare earth optical materials because thecharacteristics of the4f electrons, the lurninescent intensity is decided by themicro-environment of the matrix to the rare earth ions. Therefore change the nature ofthe matrix can modulate rare earth each light-emitting intensity of the band, and gainthe demand for lurninescence. For the rapid development of today’s nanomaterials,alot of new phenomena in the materials by the nanometer size is found. For thelurninescence materials, changing size of materials can chang the micro-environmentof rare earth ions in the material, thereby affecting their luminescence. Therefore, theresearch of the relationship between the dimensional changes and luminescence of thematerial has a huge significance for understanding of the microscopic structuralchanges of the nanomaterials and the use of the regulation of the size effect of changeof rare earth luminescence. The main content is as follows:In the first part, the sample of the NaY_xGd_1-xF₄single-crystalline nanorods wereprepared via a rational hydrothermal method using oleic acid as a stabilizing agent.The microstructure analysis revealed that the as-prepared samples presented a purehexagonal phase NaY_xGd_1-xF₄structure with high quality rod-like morphology bymeans of X-ray diffraction （XRD） and transmission electron microscopy （TEM）. theNaY_xGd_1-xF₄Nanocrystallites size Able to be regulationed by changing the ratio of Yand Gd when the size of the respective ratios of100:0to0:100nanocrystalline nm.In the second part, the influence of the crystal field （J-O the parameters λ）, thematrix phonon energy and the impact of these changes for luminescence is studied,when the material the smaller size, for Eu ions doped NaY_xGd_1-xF₄photoluminescenceexcitation spectra and emission and Er ions doped upconversion spectrum. Thefollowing conclusions:1.the NaY_xGd_1-xF₄sample size decreases will increase the phonon energy ofmatrix.2. The Eu-doped NaY_xGd_1-xF₄samples have a strong fluorescence and can begain white by adjusted the proportion of the red, green, and blue light with adjustingthe materials size.3.277nm emission red light Eu-doped NaY0.85Gd0.15F4sample is the quantumcutting process, can greatly improve the utilization of UV light.4.The Er-doped NaY_xGd_1-xF₄samples in all nano-dimensions able to give thestrong green up-conversion.