Vacuum ultraviolet spectroscopic properties of KSrPO4:Tb

KSrPO₄:Tb³⁺ phosphors were prepared by a solid-state method and their photoluminescence properties were investigated under vacuum ultraviolet excitation. In the excitation spectrum monitoring at 544 nm, the band in the region of 120-162 nm can be attributed to be the overlap of host absorption and charge transfer transition of O²⁻ → Tb³⁺, and the band ranging from 162 to 300 nm was assigned to the f-d transition of Tb³⁺. The photoluminescence spectrum shows that the phosphors exhibited a strong green emission around 544 nm corresponding to the ⁵D₄ → ⁷F₅ transition of Tb³⁺ under the excitation of 147 nm. Optimal emission intensity was obtained when x = 7% in KSr_1-xPO₄:xTb³⁺ and the luminescent chromaticity coordinates were calculated to be (x = 0.317, y = 0.522) for KSr_0.93PO₄:7%Tb³⁺.