Preparation And Properties Of Pr And Co Doped Lanthanum Borate Powders

In the past two decades,with the continuous progress of new technology,the research field of fluorescence has made great progress.With the increasing demand for ultraviolet and visible laser sources,borate based fluorescent materials were studied in this paper.After adjusting the synthesis conditions or adding doped ions,borate based fluorescent materials have chemical stability and tunability in the ultraviolet visible range.Excellent properties contribute to the development of high performance electronic and optical devices.In this study,LaBO₃matrix materials,Pr³⁺doped,Co²⁺doped and Pr³⁺,Co²⁺co-doped LaBO₃luminescent materials were prepared by solution combustion method.The experimental conditions,such as the type of combustion agent,the amount of combustion agent,the best crystallization temperature and the best holding time,were investigated.The optimal crystallization temperature and doping ratio of the doped LaBO₃luminescent materials were investigated.The products were characterized by X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy,UV visible diffuse reflectance spectroscopy and fluorescence spectroscopy.The specific research contents are as follows:(1)A series of LaBO₃matrix materials were prepared by solution combustion method.XRD analysis showed that the crystallinity of LaBO₃increased with the increase of crystallization temperature.SEM showed that the sintering phenomenon occurred when the temperature was higher than 900?.The grain size and crystallinity of the material prepared with glycine as combustion agent are better than those prepared with mannitol as combustion agent.The optimum preparation conditions were obtained as follows:glycine as combustion agent,molar ratio of reactants La(NO₃)₃·n H₂O:H₃BO₃:C₂H₅NO₂=3:3:5,crystallization temperature850?,holding time 4 h.The results show that the crystal structure and morphology of the material are the best.(2)A series of LaBO₃:Pr³⁺luminescent materials were prepared by solution combustion method with Pr as doping element.The effects of temperature on X-ray diffraction and morphology of the materials were investigated.The fluorescence results show that the optimum doping amount of LaBO₃:Pr³⁺is 3.0%,and the luminescence intensity decreases with the increase of ion doping ratio,which is attributed to the concentration quenching of the luminescent material.(3)A series of LaBO₃:Co²⁺luminescent materials were prepared by solution combustion method with Co as doping element.The effects of temperature on X-ray diffraction and morphology of the materials were investigated.The doping of Co²⁺can improve the fluorescence intensity.(4)A series of LaBO₃:Pr³⁺and Co²⁺luminescent materials were prepared by solution combustion method,and the effects of temperature on the X-ray diffraction and morphology of the materials were investigated.Compared with single ion doping,the fluorescence intensity of Pr³⁺and Co²⁺co-doping is greatly improved.Near ultraviolet light can be used as excitation source to obtain strong emission spectrum.The prepared luminescent materials have potential application value in the field of luminescence.