The Studies On ZnO:Eu³⁺ Nanaomaterials Eu³⁺ Occupy The Sites In The Crystal Lattice And Optical Property

In modern optoelectronic materials, rare earth ions, as the light emitting material material, play an important role in solid light emitting material. This is because the rare earth element ion electron shell has a unique structure. After rare earth ions doped the crystal, the crystalline material exhibits excellent optical and electrical properties. In recent years, the preparation and photoelectric physical properties of rare earth ions doped semiconductor nanocrystals have attention much attention. Rare earth doped ZnO can be used as a matrix of fluorescent material, which can be widely used in light-emitting diodes, liquid crystal displays, fluorescent probes and other products.Through three different methods ?urea precipitation method, a chemical solution, solvent?, we obtained different morphology of ZnO:Eu³⁺ nanomaterials. By X-ray diffraction?XRD?, scanning electron microscopy electron microscopy?SEM?, fluorescence spectroscopy?PL?, Raman spectroscopy?Raman? and other test methods, samples were characterized in structure, morphology and optical properties. We studied the influence of Eu³⁺ ion doping and annealing temperature on nanomaterials morphology, particle size, and Eu³⁺ occupy the position in ZnO:Eu³⁺ crystal lattice and Optical property. The results of the present study are as follows:1.We used three different methods preparing ZnO:Eu³⁺ nanomaterials. Relative strong XRD diffraction peak intensity by three preparation methods, indicats that the crystalline properties of the samples are good. By comparing standard diffraction pattern of ZnO, it shows Eu³⁺ doped ZnO crystals are hexagonal structure. Eu2O3 diffraction peaks was not found in the sample prepared by urea precipitation method, solution chemistry method, which shows Eu³⁺ have enter into the ZnO lattice. In samples prepared by solvent method, the diffraction peak Eu2O3 was found in approximately 28° of the XRD pattern, which indicates a small amount of surface precipitation Eu2O3. However, due to the less doping, the diffraction peak intensity is comparatively weak.2. By SEM analysis, we obtained samples of different morphologies. Among them, the size of particles of Eu³⁺ doped ZnO nanoparticles prepared by urea precipitation is 100-120nm; the size of particles prepared by solution chemistry method is 60?80nm; the size of particles prepared by solvent is 40-60nm. With the increase of the doping, the size of nanocrystals reduced. As the annealing temperature the size of the nanocrystals increased.3.Eu³⁺ doped ZnO sample is analyzed by using fluorescence. After Eu³⁺ doped ZnO, luminescence properties of the sample changes. In the light emission spectrum under excitation of 250nm, red light emission was found weak peak at 612nm expect the original blue-green light. This is the Eu³⁺ ions 5D0?7F2 transition. We found that band gaps and defects in ZnO luminescent weakened with doping of increasing which confirmed ZnO energy transfer Eu³⁺ ions.4.location selection and Raman spectroscopy of Eu³⁺ doped ZnO were analyzed. In the emission spectrum of the light under 532nm excitation, we found from Eu³⁺ions 5D0?7F1 ?590nm? magnetic dipole transition and 5D0?7F2?612nm? electric dipole transition. Also found that the 5D0?7F2 electric dipole transitions split into three peaks ?612nm,615nm,623nm?, which indicats that most Eu³⁺ ions occupy the C3 position of ZnO, substitute Zn²⁺position. The 5D0?7F2 electric dipole transitions will be split into four peaks ?612nm,614nm,621nm,628nm? was found in samples prepared by solvent method illustrate the Eu³⁺ ions occupy S6 positions of Eu2O3, and samples have some Eu2O3 precipitation. In Raman spectroscopy, we found E2 scattering peaks ?including E2high and E2low? significantly reduced after a small amount of Eu³⁺ ions doped, further confirmed of Eu³⁺ ions replaced Zn²⁺ ions after Eu³⁺ doped ZnO.