Synthesis and photoluminescence of Eu 3+ and Mn 2+ doped double phosphates KMLa(PO 4) 2 (M = Zn, Mg)

Abstract

Two compounds, KMgLa(PO 4) 2 and KZnLa(PO 4) 2 doped with Eu 3+ and Mn 2+ ions, have been synthesized by a conventional solid-state method at 850 °C. Structures of KMgLa(PO 4) 2 and KZnLa(PO 4) 2 have been investigated and confirmed by X-ray diffraction and photoluminescence spectra. The results indicate that the compounds have remained the monoclinic structure of LaPO 4 with space group of C s when (K +, Mg 2+) or (K +, Zn 2+) could substitute half of the La 3+ ions. Under an ultraviolet source, KMgLa(PO 4) 2:Mn 2+ has shown a bright red phosphorescent color, while KZnLa(PO 4) 2:Mn 2+ has shown an orange–red emission which is assigned to the electronic transition of 4T 1( 4G)– 6A 1( 6S) of Mn 2+ in strong crystal field.