Construction And Photoluminescence Properties Of One-dimensional Hierarchically Structure Rare Earth-based Nanofibers

Rare earth-based luminescent materials with one-dimensional nanostructure are widely employed in optical display systems,lasers and optoelectronic devices fields.The research to synthesis the rare earth-based luminescent materials with controlled morphologies and size distribution is a long-term project.In this paper,one-dimensional hierarchically structure of rare earth phosphate and rare earth oxide luminescent materials with large specific surface area and high luminous efficiency were synthesized by electrospinning method.The structure,size and micro-morphology were investigated by X-ray diffraction?XRD?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,thermogravimetric analysis?TG?Brunner-Emmet-Teller?BET?and X-ray photoelectron spectroscopy?XPS?.The photoluminescence properties of the one-dimensional hierarchically structure materials were assessed by photoluminescence spectrum?PL?.The results are as follows:1.In this paper,based on the organic polymer polyvinylpyrrolidone?PVP?as spinning aids,the Eu³⁺doped one-dimensional hierarchically structure lanthanum phosphate?LaPO₄:Eu?nanofibers with different diameters and high quantum yield were synthesized by electrospinning method combined with high-temperature calcination method.One-dimensional hierarchically structure oxygenated phosphate?La₃PO₇:Eu?nanofibers was synthesized by adjusting the amount of spinning aids?PVP?.A series of LaPO₄:Eu nanofibers with lengths exceeding 5?m and diameters of 360-480 nm,320-450 nm,280-420 nm,150-240 nm and 180-290 nm were obtained through adjusting the mass of the spinning aids.TEM images display that the LaPO₄:Eu were one-dimensional hierarchically structure nanofibers formed by ordered arrangement of nanoparticles.BET results showed that the LaPO₄:Eu nanofibers have different specific surface area due to different diameters.The effect of PVP quality on the size,composition and specific surface area of the target products were discussed.The structure-activity relationship between the size,specific surface area and photoluminescence properties of the products was further studied.It was found that the the absolute quantum yield of the lanthanum phosphate product increased with increasing specific surface area.However,there was no correlation between photoluminescence lifetime and specific surface area.LaPO₄:Eu nanofibers with different diameters have long photoluminescence lifetimes which are 3.498 ms?4.612ms?4.728ms?3.443ms and 4.778 ms.When the diameter of LaPO₄:Eu nanofibers was 150-240 nm,its surface area and absolute quantum yield are 264m²/g and 94.6%,respectively.The LaPO₄:Eu nanofibers with high quantum yield are expected to have potential applications in lighting and display fields.2.In this paper,based on the organic polymer polyvinylpyrrolidone?PVP?as spinning aids,one-dimensional hierarchically structure La₂O₃:Ln(Ln=Sm³⁺,Eu³⁺,Dy³⁺)nanofibers with hexagonal phase were synthesized by electrospinning method combined with high-temperature calcination method.A series of La₂O₃:Eu nanofibers with lengths exceeding 10?m and diameters of 260-360 nm?110-170 nm and 180-250 nm were obtained through adjusting the mass of the spinning aids.The effect of the PVP quality on the morphology and size of the target products were discussed.The photoluminescence properties of the one-dimensional hierarchically structure La₂O₃:Ln(Ln=Sm³⁺,Eu³⁺,Dy³⁺)nanofibers were studied.It was found that La₂O₃:Ln(Ln=Sm³⁺,Eu³⁺,Dy³⁺)have strong fluorescence properties,especially La₂O₃:Eu nanofibers have strong red photoluminescence emission,long photoluminescence lifetime and high color purity.The phosphate adsorption performances and adsorption kinetics of La₂O₃:Eu nanofibers have been investigated.The La₂O₃:Eu nanofibers showed an adsorption capacity of 172.7 mg/g for phosphate.It was found that the La₂O₃:Eu³⁺nanofibers had a strong adsorption and removal ability for low-concentration phosphate pollutants in simulated wastewater,and had a high selectivity for concentration phosphate pollutants.The study suggested that the prepared La₂O₃:Eu³⁺nanofibers can be used to removal from utrophication water.3.In this paper,we systematically explore the effect of electrospinning process parameters?such as spinning voltage and receiving distance?and the quality of spinning aids on the electrospinning effect.The effect of calcination temperature on the morphology,structure and composition of the target products was investigated.The optimal electrospinning voltage,receiving distance and the quality of the spinning aids were determined for electrospun rare earth phosphates and rare earth oxide inorganic substances.The results provide a reference for controlled synthesis of other 1D nanostructured rare earth inorganic luminescent materials.