Rare Earth Doped Ca₉Gd?PO₄?₇ Structure Luminescent Material Preparation And Performance Studies

As one of the key research directions of the country's new materials,new types of luminescent and display materials have gradually attracted the attention of the society.Phosphate materials have attracted attention in many matrix materials for synthetic luminescence and display materials because of their numerous advantages,such as wide sources,stable performance,good light transmission,and simple synthesis conditions.This article through the domestic and foreign literature research,combined with the research foundation of their own research group,selected Ca₉Gd?PO₄?₇ as a synthetic luminescent material matrix material,through two-step high-temperature solid-state synthesis of phosphors,specific research results are shown below:A novel single-phase yellow-white phosphor Ca₉Gd?PO₄?₇:Dy³⁺was prepared using a traditional high-temperature solid-state method.The crystal structure was investigated by X-ray diffraction to confirm that the prepared sample was a pure phase.Excited by 353 nm UV light,the obtained phosphor showed three strong emission with one peak in the blue region at 486 nm,a yellow region at 576 nm,and another at 667 nm in the weak red emission band.The emission color of all samples was located near the perfect yellow region,and the optimal chromaticity coordinates and interconnect color temperature?CCT?were determined as x=0.35,y=0.40 and4989K.Using a near-UV 390 nm chip as the excitation light source,a Ca₉Gd?PO₄?₇:Dy³⁺phosphor was packaged to produce a LED light that can emit white light.The results show that the prepared Ca₉Gd?PO₄?₇:Dy³⁺phosphor can be applied to the yellow light n-UV-LED emitting device.A series of single-phase phosphors with the structure of Ca₉Gd_1-x?PO₄?₇:xSm³⁺?x=0.01,0.03,0.05,0.07,0.10,0.20,0.30,0.50 mol?were synthesized by two-step high-temperature solid-state reaction.The sample structure was characterized by XRD,indicating that the prepared sample was pure phase.When the excitation wavelength is 406nm and the Sm³⁺doping concentration is 0.20mol,the corresponding highest peak reaches the strongest emission,and then decreases with increasing concentration.Using CIE chromatographic analysis,it is found that the synthesized luminescent material shows a redshift with increasing doping concentration.Phenomenon;color temperature analysis found that synthetic luminescent materials emit warm red light when the concentration is below 0.05 mol.A series of luminescent materials with tunable Ca₉Gd_0.8-x?PO₄?₇:0.20Tb³⁺,xSm³⁺?x=0.03,0.05,0.10,0.20,0.30 mol?were synthesized by high temperature solid-state reaction.By XRD analysis,the sample was confirmed to be pure phase.The energy transfer of Tb³⁺/Sm³⁺in the phosphor was confirmed by fluorescence spectra and fluorescence decay curves,and the energy transfer mechanism was dipole-quadrupole interaction.By adjusting the ion concentration of Sm³⁺,the synthesized luminescent material is tunable under ultraviolet light irradiation,and the luminescent color changes from green to red as the concentration increases.Therefore,Ca₉Gd?PO₄?₇:Tb³⁺,Sm³⁺phosphors can be used as potential materials for n-UV white light emitting diodes and other optical devices.The novel luminescent materials Ca₉Gd?PO₄?₇:Ce³⁺and Mn²⁺which were co-doped into the Ca₉Gd?PO₄?₇ matrix material were synthesized by two-step high-temperature solid-state reaction of carbon in the presence of transition metal divalent manganese ions and trivalent antimony ions.XRD was used to characterize the structure and the energy transfer between the two was analyzed.The stability of the sample under high temperature condition was verified by the variable temperature spectroscopy.