Microstructure Control Of Yttrium-based Oxides Host Materials And Their Enhanced Effect On Luminescence Properties

Rare earth luminescent materials with long lifetime, large penetration depth, and high fluorescent stability have attracted great attention in diverse research fields, ranging from displays, lasers, biomedical, anti-counterfeiting, optical storage to detection. Yttrium oxides based compounds such as Y₂O₃, YVO₄ are widely studied host materials, due to the high stability. Recent studies demonstrate that there is a significant correlation between the morphology and luminescence property of the Ln³⁺ ions doped Y₂O₃ and YVO₄. More recently, important enlightenment about the development of luminescent materials is provided by the excellent performance of multi-shell hollow structures in various fields. Although many research teams have joined the relevant research, studies on the preparation of Y₂O₃ and YVO₄ multi-shell hollow spheres by the simple approach are not deepgoing. Therefore, with the morphology as starting point, it is important to develop the yttrium oxides based luminescent materials with high luminescent intensity. It also has the vital significance to study the growth mechanism and the relationship between the morphology and the luminescence properties of the luminescent materials.Herein, we report a novel synthetic strategy for Y₂O₃ and YVO₄ multi-shell hollow spheres with high crystallinity and controlled shell numbers. The synthetic criterion and formation mechanism of the multi-shell hollow spheres and the Y₂O₃ nanoplates have been proposed in detail. The effects of morphology control and the luminescent properties on luminescent materials are discussed to. The key research results are show as follows.2D Y₂O₃ nanoplates were successfully synthesized by using the facile hydrothermal method. By mainly adjusting the pH value of the original solution, reaction temperature, hydrothermal reaction time, the Y₂O₃ nanoplates is obtained. The Eu³⁺ doped Y₂O₃ nanoplates exhibite strong red photoluminescence emission than the Y₂O₃Eu³⁺ nanorods.Y@C composite carbonaceous spheres was successfully synthesized via the simple hydrothermal approach, and by adjusting the concentration of yttrium nitrate, the content of Y³⁺ ions in the Y@C composite carbonaceous spheres could be controlled. Uniform Y₂O₃ multi-shell hollow spheres with shell number up to quadruple could be successfully synthesized via programed calcination. The research results of Y₂O₃.Eu³⁺ multi-shell hollow spheres revealed that the upconversion photoluminescence intensity enhanced with the shell number increase. Y₂O₃:3mol%Yb³⁺/lmol%Er³⁺multi-shell hollow spheres has the highest upconversion photoluminescence intensity which enhanced with the shell number increase. The excellent luminescent properties of Y₂O₃:Yb³⁺/Er³⁺ multi-shell hollow spheres could be attributed to the multiple reflections of their special multi-shell hollow structures.Herein, we report a novel route of metal ion-carbonaceous composite spheres template strategy for the synthesis of multicomponent complex oxides multi-shell hollow spheres. The composite Y@C spheres are employed as the hard template for the adsorption of VO₃- anion under the hydrothermal treatment. The complex oxide YVO₄ multi-shell hollow spheres with uniform morphology, high crystallinity, and controlled shell number up to the triple could be successfully synthesized under the programmed thermal annealing. Moreover, with doping of Yb³⁺ and Er34, the as-synthesized YVO₄:Yb³⁺/Er³⁺ multi-shell hollow spheres can offer superior upconversion photoluminescence which is much higher than the YVO₄:Yb³⁺/Er³⁺ nanoparticles, and the upconversion photoluminescence intensity enhanced with the shell number increase. The contrast experiment reveal that the enhanced NIR excitation light absorbance is originated from the multiple reflections of the multilevel structure. This is benefits to the enhancement of the upconversion luminescence property. More importantly, a major breakthrough has been achieved on the controlled synthesis of complex oxides hollow-shell spheres with the help of metal ion-carbonaceous composite spheres template approach.