Synthesis, structure and luminescence properties of phosphates A1-3xEuxZr2(PO4)3 (A--alkali metal)

The solid solution row A1−3xEu3+xZr2(PO4)3, where A = Na, K, Rb, Cs and x ranging from 0 to 0.25 was obtained by methods based on sol–gel processes in the presence of the salting-out agent, C2H5OH. The formation of phases of the structural type NaZr2(PO4)3 (NZP) and their crystallization in the crystal forms belonging to the space group R3¯c (0 ≤x≤ 0.1) and P3¯c (x= 0.25) were determined. Morphotropic transition occurred. Trivalent europium was included as a local probe. Its electric and magnetic dipole was used to characterize the substitution rule and the localization of this cation in the structure, which is in agreement with the structural characterization. It appears that europium is located in the M1 and M2 sites as a function of the Eu3+ concentration