Investigating Cationic Distribution,Defect Structure and Phosphor Characteristics of Na2Sm2Ca6(PO4)6F2

摘要

Sm3+ based fluorapatite matrix viz.Na2Sm2Ca6(PO4)6F2 was synthesized and characterized by X-ray diffraction technique,infrared spectroscopy,EDX elemental mapping.Thermal stability was checked by differential thermal analysis technique.Presence of oxygen vacancy related defect centers were confirmed by EPR study,which create several electronic states inside the band gap of the material and give rise to photoemission in the blue and green region in the PL spectra.From the characteristics emission of Sm3+ and its decay profile,it has been confirmed that Sm~(3+)ion prefers to occupy the less crowdedM2 A site where Ca~(2+)ion is having 7-co-ordination and a direct linking to F~-atom.PL decay study also showed that there are two different kinds of oxygen vacancies namely F and F~+ center.Finally,based on calculation of International Commission on Illumination(CIE)color coordinates,it has been observed that the compound is a white light emitting material,which has several advantages over the other white light emitting source being a single phase compound.