Preparation And Luminescence Properties Of Rare Earth Doped Alkaline Earth Aluminosilicate Phosphors

In recent years, phosphors have attracted worldwide attention. Consultingliteratures and results, combined with our system, we synthesized a series rare earthdoped aluminosilicate phophors through high temperature solid state method.,such asM₂Al₂SiO₇（M=Ca，Sr，Ba） and MAl₂Si₂O₈（M=Ca, Sr, Ba）. Therefore, this thesisstudies the topic of aluminosilicate phophors doping with rare earth, including the keytechnology improvements and the related application.1. The Tb³⁺and Gd³⁺co-doped M2Al2SiO（7M=Ca，Sr，Ba）green phosphors wereprepared by solid state reaction. The results indicate that the structure of theM₂Al₂SiO₇（M=Ca，Sr）is tetragonal, and the doping of rare earth elements can notaffect the phase composition of the M₂Al₂SiO₇（M=Ca，Sr，Ba）compounds. Theexcitation peak of the series phosphors is at230nm, which is attributed to the4f-5dtransition of Tb³⁺ions, and the emission peak at545nm is attributed to5D4â†'7F5transition of the Tb³⁺ions.. The luminescence intensity increased with the increasingof ionic radius of the alkaline earth (Ca²⁺＞Sr²⁺＞Ba²⁺) in the system and the lifetimeof the Tb³⁺activated M₂Al₂SiO₇phosphor exhibits opposite. In this system, the energytransfer mechanism from Gd³⁺to Tb³⁺was discussed.2. The MAl2Si2O（8M=Ca，Sr，Ba）:Eu³⁺red phosphors were synthesized by solidstate reaction method. In this system, due to a large mismatch in valence betweenEu³⁺and M²⁺, we added the Li+＞Na+＞K+as the charge compensators. The resultsshow that the addition of the charge compensators （Li+＞Na+＞K+） do not affect theshapes of excitation, emission spectra and the emission peak and affect the phasecomposition of the MAl₂Si₂O₈（M=Ca，Sr，Ba）compounds. The emission peak at615nm is attributed to the5D0â†'7F2of Eu³⁺ions. The relative intensity increases withthe increases of the ionic radii of alkali metal ions, which are as charge compensators （Li+＞Na+＞K+）. Take SrAl₂Si₂O₈for example, the doping concentration of Eu³⁺ionsis1.5mol%.3.BaAl₂Si₂O₈has four phases in nature. However, the solid state reaction canlead to creating the hexagonal phase and monoclinic phase. We discussed the Ce³⁺doping different phase how to affect the luminescent intensity. The most favorabletemperatures to formation the hexagonal phase and monoclinic phase are1100℃and1300℃, and the doping concentration of Ce³⁺ions is3mol%and9mol%.