Nano/micro powders of Nd3+-doped YPO4 and LuPO4 under structural and spectroscopic studies. An abnormal temporal behavior of f-f photoluminescence

Abstract We report a detailed analysis of both structural characterization and high-resolution spectroscopic properties of Nd3+-doped YPO4 and LuPO4 in the form of nano/micro powders. LuPO4, like YPO4 crystalizes in a zircon-type tetragonal system. Nd3+ ion in substitution of Lu3+ or Y3+ cations occupies the main symmetry site D2d and the presence of additional components in the spectra may indicate the presence of Nd3+ clusters, first Nd3+ pairs. For both types of compounds (with Lu 3+ and Y3+ ion in the host lattice) the 4F3/2 excited level decay times recorded at 77 K have shown an abnormal temporal behavior of Nd3+ photoluminescence. This phenomenon is observed both for nano and micro-powdered samples.