Study On The Controllable Synthesis Of Rare Earth Doped Vanadate And Their Photoluminescence Performance

With the rapid development of light emitting diode including plasma light emitting display technology,which has put forward a more strict requirements to the phosphor for particle size,the stability of the performance,sustainability of luminous and luminous intensity.In a large number of luminescent materials,luminescent materials of rare-earth vanadate shows the better fluorescence properties for its unique crystal structure and significant nano effect.More than this,also has a good chemical properties and thermal properties.Therefore,study the appearance design and controlled synthesis of rare earth vanadate nanomaterials,explore the effect of micro size,structure and morphology for its performance and expand its application in new areas,has the actual social value and economic value,also is the hot spots in this field.In this paper,a series of rare earth vanadate were prepared by hydrothermal method.Using the characterization methods of XRD,SEM,PL,TEM and HRTEM to study the structure and morphology of the prepared samples.The main results were as follows:1?pure m-LaVO₄:Eu³⁺ and t-LaVO₄:Eu³⁺ nanocrystals were prepared by an EG-assisted hydrothermal method with regular shapes.A series of controlled experiments showed that the pH value of a mixed solution,the volume ratio of EG/H₂O and the dosage of the doped Eu³⁺ all had an important effect on the sizes and shapes of the final products.Furthermore,the constitutional unit of the products changed from 0D to 2D with an increase in the EG dosage.The PL results showed that t-LaVO₄ doped with Eu³⁺ ions had a better luminescence properties than m-LaVO₄ due to its special structure.2?The phase-dependent YVO₄ nanocrystals were synthesized by the hydrothermal process assisted with the addition of different amines?TETA,ETA,EDA?.The XRD patterns of samples indicated that its belong to the tetragonal structure with a space group of 141/a.The SEM results showed that the addition has played an important role in the generated process of morphology.Meanwhile,the fluorescence properties were also studied systematically.The results indicated that under the excitation at 280 nm,YVO₄:Eu³⁺nanocrystals emit red emission arise from the transitions ⁵D₁-⁷F₁ and ⁵D₀-⁷F_J?J=1,2,3,4?of the Eu³⁺ ions.The intensity of red emission was not only related to the doped concentrations of Eu³⁺,but also related to the types of amines.Y0.95Eu0.05VO₄ were found to show the maximum luminescence performance as represented by a long lifetime of 1.14 ms when EDA was acted as an addictive.3?The YVO₄:Eu³⁺ and YVO₄:Eu³⁺/Ba²⁺ nanocrystals were prepared viaa NaNO₃-assisted hydrothermal methods.XRD pattern,SEM,TEM,HRTEM and PL measurements were carried out to characterize their structure and morphology,also luminescence properties.Under the excitation of photon energy absorped by YVO₄ host material,YVO₄:Eu³⁺/Ba²⁺phosphors has displayed a strong red emission,which were several times higher than YVO₄:Eu³⁺ samples which prepared the same conditions.What was more,moderate concentration of Ba²⁺ doping were good for the improving of lifetime,the fluorescence lifetime of up to 1.14 ms after doping Ba²⁺.