Reasearch On Preparation Of Y₂O₃:Eu Nanomaterial And Their Luminescence Properties

Yttrium oxide（Y₂O₃）is an important rare earth oxide with excellent physical and chemical properties.The Y₂O₃:Eu nanomaterial formed by doping Eu³⁺ions into the Y₂O₃ matrix has the advantages of strong fluorescence emission,long fluorescence lifetime,good stability and low toxicity,having attracted much attion of scientific community.At present,the preparation method of nanomaterials is difficult to rapidly synthesize shape-controllable spherical Y₂O₃:Eu nanomaterials in a short time,and the nanomaterials prepared by such mothodes exhibit low fluorescence performances.In order to solve those problems,the microwave-enhanced ultrasonic synthesis method is used to achieve the goal of preparing spherical Y₂O₃:Eu nanomaterials in a short time.The prepared nanomaterials have excellent fluorescence emission intensity,high quantum yield and long fluorescence lifetime.In this paper,spherical Y₂O₃ nanomaterials were prepared using microwave-enhanced ultrasonic synthesis method.By investigating the effects of reaction temperature,reaction time,ultrasonic power and urea concentration on the morphology and particle size of Y₂O₃ precursors,the optimum conditions for preparing spherical Y₂O₃ precursors is as follows:reaction temperature is 90°C,reaction time is 2 h,the ultrasonic power is 300 W and the urea concentration is1.5 mol/L.The prepared spherical Y₂O₃ precursor has minimum particle size of110 nm.The effects of calcination temperature of the precursor on the cubic Y₂O₃nanomaterials were investigated.The results show that Y₂O₃ maintains the spherical morphology of the precursors,and the average particle size ranged from17.2 nm to 34.7 nm.The increase of calcination temperature promotes the formation of Y₂O₃ crystal structure.On this basis,red-emitting spherical Y₂O₃:Eu nanomaterials were prepared.The effects of Eu³⁺ions concentration and calcination temperatures on its morphology and fluorescence properties had been investigated.Studies show that low concentrations of Eu³⁺ions have little effect on the morphology and crystal configuration of the Y₂O₃ matrix.With the increase of Eu³⁺ions concentration,the particle size of Y₂O₃:Eu nanomaterials gradually increases,and the intensity of fluorescence emission increases firstly and then decreases.When the Eu³⁺ion concentration is 3 mol%,the product has the longest fluorescence lifetime of 1.57ms and the maximum quantum yield is 80.88%.Calcination temperatures have little effect on the morphology of spherical Y₂O₃:Eu nanomaterials,but the fluorescence performance has been improved as the calcination temperature increases.When calcination temperature is 850°C,the fluorescence lifetime of the product is up to 1.75 ms.Red-emitting LED devices were assembled using Y₂O₃:Eu nano-fluorescent materials.The electrical and optical properties of the LED devices had been characterized and analyzed.The studies found that the assembled LED devices have the same turn-on voltage of 3.10 V.The increase of Eu³⁺ions concentration and calcination temperature,the electrical and optical properties of LED devices have improved.When Eu³⁺ion concentration is 3 mol%and calcination temperature is 650°C,LED device has the maximum luminescence power of 0.35mW and the maximum color rendering index of 55.3.