Structure and luminescence properties of silver-doped NaY(PO3)4 crystal

Single crystals of NaY(PO3)4 and Ag0.07Na0.93Y(PO3)4 have been synthesized by flux method. These new compounds turned out to be isostructural to NaLn(PO3)4, with Ln=La, Nd, Gd and Er [monoclinic, P21/n, a=7.1615(2) A, b=13.0077(1) A, c=9.7032 (3) A, β=90.55 (1)o, V=903.86(14) A3 and Z=4]. The structure is based upon long polyphosphate chains running along the shortest unit-cell direction and made up of PO4 tetrahedra sharing two corners, linked to yttrium and sodium polyhedra. Infrared and Raman spectra at room temperature confirms this atomic arrangement. The luminescence of silver ions was reported in metaphosphate of composition Ag0.07Na0.93Y(PO3)4. One luminescent centre was detected and assigned to single Ag+ ions. - Graphical abstract: The presence of only one Ag+ luminescence centre is the result from the perfect isolation (Ag+-Ag+=5.90 A) of each oxygenated silver site (AgO8 polyhedra) sharing two faces and one corner with three yttrium polyhedra