The role of excess Zn2+ ions in improvement of red long lasting phosphorescence (LLP) performance of β-Zn3(PO4)2:Mn phosphor

Influences of excess Zn2+ ions and intrinsic defects on red (lambda = 616 nm) phosphorescence of beta-Zn-3(PO4)(2):Mn2+ are systematically investigated. It is clearly observed that red long lasting phosphorescence (LLP) properties of Mn2+, such as brightness and duration, are largely improved when excess Zn2+ ions are co-doped into the matrix. Photoluminescence (PL), LLP and thermoluminescence (TL) spectra indicate that Mn2+ ion acts as luminescent center whereas oxygen vacancy associated to Zn2+ ion plays a significant role in electron trap. The TL peak for oxygen vacancy is centered at 343 K, the depth of which is suitable for improvement in LLP performance of Mn2+ at room temperature. The possible mechanism for this phenomenon of red LLP of Mn2+ beta-Zn-3(PO4)(2):Mn2+ with excess of Zn2+ is explained by means of a competitively trapping model. (C) 2003 Elsevier Inc. All rights reserved.