Preparation And Luminescent Properties Of Two New Apatite Structured Luminescent Materials

White LED,as a new lighting source with better development situation,has attracted more and more attention because it conforms to the global trend of environment-friendly,low-carbon emissions and energy saving.There are two most common ways to obtain white LEDs:one is the combination of blue chip and yellow phosphor,but this way is limited by the lack of red components which results in poor color rendering index;the other is using the near UV LED excites red,green and blue phosphors,however,the problem of color reabsorption between the three phosphors greatly reduces the luminous efficiency.Therefore,it is imperative to promote the research on novel single-phase white and red phosphors with excellent performance which can be stimulated by near-ultraviolet or blue light chips.Compounds with apatite structure are regarded as excellent matrix crystals of rare earth luminescent materials owing to their rich crystal field environment.Based on the background,two kinds of new phosphors with apatite structure were prepared by high temperature solid-phase method in this paper,and the effects of structure substitution on their crystal structure and luminescent properties were investigated.The main results of this paper are summarized as follows:?1?NaLa₉?SiO₄?₆O₂:xSm³⁺fluorescence material with novel apatite structure was successfully prepared by high temperature solid phase method.The doped Sm³⁺ions can be successfully introduced into the NaLa₉?SiO₄?₆O₂ lattice and do not change the crystal structure of the matrix,and the fluorescent powder samples are all pure phase apatite structure.The prepared phosphors can emit red light,the strongest emission peak is near 605 nm.With the increase of Sm³⁺concentration,the luminescent intensity first increases and then decreases due to concentration quenching,and the best doping concentration is estimated to be 0.1 mol.In addition,the temperature spectrum and fluorescence lifetime of the sample with the best doping concentration were measured and fitted.The thermal stability of the phosphors is excellent,and the luminescent intensity of the phosphors can be maintained at about 67.9%of the room temperature at 150?.?2?A new single-phase white Sr₄Gd₆?SiO₄?₆F₂:xDy³⁺phosphor was prepared by high temperature solid state method.XRD and structure refinement results show that the samples prepared in the experiment are pure phase.The series phosphors emit white light,and their characteristic emission peaks are located at about 480nm and 573nm respectively.The CIE coordinate values?0.325,0.356?are very close to the ideal white chroma coordinates?0.333,0.333?,which indicates that this series of new single-phase white phosphors have potential application prospects.