The Study On The Rare-Earth Luminescent Materials

Because of the excellent optical properties that the Rare-earth Luminescent Materials have been widely used in all fields of our lives,and the rare earth phosphate have become the best of them for their physical chemical properties,La-phosphate(LaPO₄) is more often used as matrix doped other rare earth ion.As the size of the sample which prepared in high-temperature solid-state reaction method can not reach to nano-level,therefore,this paper introduces nano-luminescent materials prepared in the wet coprecipitation method, and by changing the ion concentration of the luminescent center(Eu³⁺) to get more excellent nano-luminescent materials in optical properties.This paper discusses that the nano-luminescent material LaPO₄:Eu³⁺ which is prepared in oxalate precipitation method and the influencing factors of its optical properties.In this experiment,with oxalic acid for the coordination agent,with used the characteristic of the impurities is easy to remove in oxalate precipitation,to prepare the oxalate precipitation of a very small solubility,that is,the oxalate precursor.Dispersing the oxalate precipitation in water,and mixed with the ammonium dihydrogen phosphate(NH₄H₂PO₄) which has been configured,so that the oxalate precipitations transfer into the phosphate precipitations in full,after washing,drying,calcination,the nano light-emitting material LaPO₄:Eu³⁺ can be obtained.In the preparation process,by setting different calcination temperature and changing the concentration of luminescent center,to improve the luminous intensity of the materials,in order to get the rare-earth luminescent material which is met for the performance requirements.By using XRD,SEM, particle size analysis,infrared spectroscopy analysis,optical properties analysis to get samples characterized,comprehensively analysis the relationships between the optical properties and the micro-structure of samples,and their influencing factors.The experimental results show that the optical properties of the samples which are prepared in wet precipitation method closely relate to their calcination temperature, morphology and particle size.The higher the calcination temperature and the more uniform size and the more fine particle size,the more higher luminous intensity of the sample;on the other hand,the luminous intensity is reduced.In addition,the concentration of luminescent center has effect on the luminous intensity of sample.When the concentration of luminescent center to achieve a certain value,the luminous intensity of sample to reach the maximum,and then,with the increasing of the concentration,the luminous intensity decreasing.It does not prove that the more higher concentration of luminescent center,the greater luminous intensity,also proves that the rare-earth elements with the nature of concentration quenching.