Abstract:

LiSrBO₃:Tb³⁺ green phosphor was synthesized by means of a solid state reaction and its spectral characteristics were studied. The emission spectrum of LiSrBO₃:Tb³⁺ consists of four major bands at 486, 544, 595 and 620 nm under the excitation of near ultraviolet irradiation, which are originated from the ⁵D₄→⁷F₆, ⁵D₄→⁷F₅, ⁵D₄→⁷F₄ and ⁵D₄→⁷F₃ characteristic transitions of Tb³⁺, respectively. Monitored at 544 nm, the excitation spectrum of the phosphor extends from 220 nm to 390 nm, with the excitation peaks centered at 242, 277, 368 and 381 nm, respectively. The effect of Tb³⁺ concentration on the emission intensity of LiSrBO₃:Tb³⁺ was also investigated. The results show that firstly the intensity increases with increasing Tb³⁺ concentration, reaches a maximum value at 3%(molar fraction) Tb³⁺ and then decreases, showing a concentration self-quenching, whose mechanism is proposed as a d-d interaction based on Dexter theory. The emission intensity of LiSrBO₃:Tb³⁺ was enhanced by co-doping Li⁺, Na⁺  and K⁺.

Key words: LiSrBO3:Tb3+; Green phosphor; Spectral characteristics