Shape-Controlled Synthesis Of Monodispersed Nano-/Micro-AT（MoO₄）₂and Tunable Luminescent Properties Of Red Phosphor With Blue Exciting

This paper described a simple method of synthesis of a highly efficientphosphor by doping monovalent ions, the trivalent ion and activatorion optical properties of and conditions without any surfactant solutionmethod synthesis of nano/micro structure of the diversity. The sametime, we use X-ray diffraction （XRD）, scanning electron microscopy（SEM）, field emission scanning electron microscope （FESEM）,transmission electron microscopy （TEM）, fluorescence spectra （PL） testmethods for preparation of the product structure, morphology andoptical properties, carried out a detailed characterization, and get thefollowing results:Preparation of Li_1-mAgmLa_0.99-nY_nPr_0.01（MoO₄）₂phosphors was done bya convenient method of solid-state reaction technique in the air. Theelects of synthesis temperature, substitution of Ag⁺, La³⁺ on theLiY（MoO₄）₂crystal structure, and luminescence properties of Pr³⁺ in themolybdate host are investigated systematically. The observedexcitation and emission spectra indicate that the phosphor can beexcited electively by the blue light （440–500nm） and exhibit asatisfactory red emission at605and649nm, respectively. Thesubstitution of a little Ag+for Li+enhances the Pr³⁺ luminescenceintensity drastically. The variability of Y3+and La³⁺ content changes the emission intensity ratio of the¹D₂→³H₄and³P₀→³F₂transition, so that theCIE chromaticity coordinates of the as-prepared LiLa_0.99-nYnPr_0.01（MoO₄）₂phosphors are tuned from （0.639,0.351） to （0.653,0.337）.Theluminescence properties of Ho3+in the molybdate host also beinvestigated to drop the color temperature of white LED application inthe market.Nearly monodispersed NaY（MoO₄）₂architectures with various shapeshave been selectively prepared on a large scale by a capping agentfree hydrothermal process using Y（OH）3nanorods as a precursor. Themolar ratio of Na₂MoO₄/Y（OH）₃, the volume ratio of water/ethanol inthe mixed solvents and temperature have comprehensive and crucialinfluences on the formation of multi morphologies of NaY（MoO₄）₂. Theformation of multi morphologies is explained mainly from the viewpointof the effective concentration of Mo_O4₂-ions. At high temperature, highNa2MoO4/Y（OH）3ratio and high water/ethanol volume ratio, theeffective concentration and reactivity of reactants, especially MoO₄^2-ions, are improved, which is beneficial to the growth of3D NaY（MoO₄）₂architectures. Under UV excitation, without further annealing treatment,NaY（MoO₄）₂:0.05Eu³⁺ bipyramid micro samples show strong red emission,corresponding to the characteristic lines of Eu³⁺.