Structure and photoluminescence characterization of Tb3+-doped LaPO4 nanorods prepared via the microwave-assisted method

LaPO4 nanopowders doped with 1, 2... 10, 11, 15 and 20 mol% Tb3+ have been prepared by the microwave-assisted method. Transmission electron microscope (TEM) images indicated that the nanopowders are composed of nanorods. X-ray diffraction (XRD) analysis showed that the prepared nanorods exhibit hexagonal crystal structure and the diffraction peaks were shifted towards the higher 2 theta angle side with increasing Tb3+ dopant concentration. Raman scattering measurement found out that some of scattering lines were shifted and broadened to higher wavenumber side with increasing Tb3+ concentration. It is discovered that the photoluminescence (PL) of Tb3+ ions results from the radiative intra-configurational f-f transitions that occur from the D-5(4) exited state to the F-7(J) (J=0,1-6) ground states; the photoluminescence excitation (PLE) of Tb3+ ions takes place from the F-7(6) ground state to the D-5(J) (J=0,1-4), L-5(10), (5)G(J) (J=2-4), H-5(J) and I-5(J) exited states. It was observed that the photoluminescence intensity reached a maximum in the samples doped with 15 mol% Tb3+. Double-exponential decay of the D-5(4)-> F-7(6) emission was observed with lifetimes of similar to 5 ns and 6.35 ms. (C) 2015 Elsevier B.V. All rights reserved.