A study on the preparation and the luminescent property of Sr₂SiO₄: Tb³⁺ green phosphor by the sol-gel method

A series of(1-X)Sr₂SiO₄:XTb³⁺(X=0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06) green phosphors were synthesized by the sol-gel method, which weresuitable for UV and near-UV excitation. The structure and the luminescence properties of phosphors were characterized by X-ray diffraction, scanning electron microscopy and fluorescence spectra. The results of XRD show that the synthesized samples belong to the monoclinic β-Sr₂SiO₄ phase.It can be seen from the SEM diagram that all synthesized samples are presented as irregular block structures. The main excitation peak of Sr₂SiO₄:Tb³⁺ phosphor appears at 370 nm when the monitoring waveleng this 547 nm, which belongs to the 4f-4f characteristic transition absorption of Tb³⁺. The emission spectra of Sr₂SiO₄:Tb³⁺phosphors shows four strong emission peaks at 488 nm, 547 nm, 586 nm, 623 nm, which originates from ⁵D₄→⁷F₆, ⁵D₄→⁷F₅, ⁵D₄→⁷F₄ and ⁵D₄→⁷F₃ transitions of Tb³⁺when the excitation wavelengths are 285 nm and 250 nm, respectively. The strongest emission peak appears at 547 nm, characterized by green light emission.With the increase of doping amount of Tb³⁺, the emission intensity shows a trend of decreasing after increasing at the beginning period, that is, there is a concentration quenching effect. The luminous intensity of the sample is the strongest when the Tb³⁺ doping amount is X=0.03.