Structural Reorganization Of Rare Earth Elements In Anorthite Matrix And Its Spectroscopic Characterization

Rare earth doped luminescent materials based on inorganic materials are important inorganic functional materials,which are active in many optical applications,especially in light emitting diodes(LED).Before the advent of LED,incandescent lamps and fluorescent lamps were widely used.However,LED has many incomparable advantages compared with them,and has now replaced them as a new generation of semiconductor lighting sources.The combination of phosphor and diode is usually the main way to realize LED lighting,so the choice of phosphor has been widely concerned and studied by researchers at home and abroad.Aluminosilicate has many kinds of structures,and because of the stable structure of silicon oxygen tetrahedron[SiO₄]and aluminum oxygen tetrahedron[Al O₄],it shows good physical and chemical stability,so it is suitable to study it as the substrate material of luminescent materials.The luminescent properties of these phosphors are closely related to the absorption band in the near ultraviolet region(NUV)and the electronic energy level transitions of lanthanide rare earth elements.The purpose of this paper is to take a typical structure of sialuminate CaAl₂Si₂O₈ as the research object,to systematically study the luminescent properties of rare earth doped phosphors excited by the near ultraviolet region,at the same time,to systematically study the crystal phase structure,micro morphology,doping and other aspects of phosphors,and to summarize the rare earth elements in the matrix of aluminosilicate luminescent materials.The mode of existence is of great theoretical significance for the nature and mechanism of rare earth luminescent materials.In this paper,a series of rare earth elements doped luminescent materials substrate on calcium feldspar have been synthesized via the traditional solid-state method in the air atmosphere at different sintering temperatures.A series of analysis and characterization methods were used to study the existence of rare earth elements in the substrate and their photoluminescence characteristics in the ultraviolet region.1.The green phosphor CaAl₂Si₂O₈:Tb³⁺with different concentrations of Tb³⁺were successfully synthesized via solid-state method.Under the excitation of 325 nm ultraviolet wave,there is a green emission peak at about 545 nm.In order to explore the existence of Tb3+in the CaAl₂Si₂O₈ substrate,we doped the CaAl₂Si₂O₈substrate with relatively high concentrations of Tb³⁺on the basis of the traditional low concentrations of rare earth elements,and found that when the doping concentration x=0.70,both of the luminescent intensity of the sample and the intensity of the dominant peak at 870.0cm^-1 in the Raman spectra reached the strongest.The chromaticity coordinates of the sample at the doping concentration are(0.2692,0.5610),which is a kind of yellow green light with high color and color development.2.In the CaAl₂Si₂O₈ substrate,the white light emission of the samples are achieved by doping Dy³⁺.In order to explore the existence of Dy³⁺in the CaAl₂Si₂O₈matrix,we doped the CaAl₂Si₂O₈ substrate with a relatively high concentration of Dy³⁺on the basis of the traditional low concentration of rare earth element doping,and found that when the doping concentration x=0.70,the luminescent intensity of the sample and the intensity of the dominant peak at 847.5cm^-1 in the Raman spectra reached the strongest.The chromaticity coordinate value of the sample is(0.3423,0.4125),which is close to the color coordinate of pure white light(0.3101,0.3162).It is a kind of white light with high color temperature and color rendering.3.By doping the single substrate CaAl₂Si₂O₈with two different concentrations of rare earth elements,we found that new phases were formed in both samples.The new phase of Ca₂Tb₈(SiO₄)₆O₂ is formed spontaneously by Tb element and Ca,Si and O elements in the subtrate,which belongs to the oxyapatite system.The new phase of Dy₃Al₂(Al O₄)₃ is formed spontaneously by Dy element and Al and O elements in thesubtrate,which belongs to the garnet system.We have successfully synthesized the pure phase of two new phases,and their Raman spectra are similar.The results show that the nature of luminescent of the samples which doped with different concentrations of rare earth elements is due to the existence of new phase.