Crystal growth, layered structure and luminescence properties of K2Eu(PO4)(WO4)

Abstract

K₂Eu(PO₄)(WO₄) has been prepared via the high-temperature solution growth (HTSG) method using K₂WO₄–KPO₃ molten salts as a self-flux and characterized by single-crystal X-ray diffraction analysis, IR and luminescence spectroscopy. The structure of this new compound features a 2D framework containing [EuPO₆]⁴⁻ layers, which are composed of zigzag chains of [EuO₈]_n interlinked by slightly distorted PO₄ tetrahedra. Isolated WO₄ tetrahedra are attached above and below these layers, leaving space for the K⁺ counter-cations. The photoluminescence (PL) characteristics (spectra, line intensity distribution and decay kinetics) confirm structural data concerning one distinct position for europium ions. The luminescence color coordinates suggest K₂Eu(PO₄)(WO₄) as an efficient red phosphor for lighting applications.