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

- Hexagonal LaPO4:Tb nanorods have been prepared by the microwave-assisted method.
- XRD peaks were shifted to higher 2θ angle side with increasing Tb3+ concentration.
- Some Raman peaks shifted and broadened to higher energy with rising Tb3+ content.
- The 5D4→7F5 emission of Tb3+ ion exhibits a double-exponential decay.

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 2θ 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 5D4 exited state to the 7FJ (J=0,1-6) ground states; the photoluminescence excitation (PLE) of Tb3+ ions takes place from the 7F6 ground state to the 5DJ (J=0,1-4), 5L10, 5GJ (J=2-4), 5HJ and 5IJ 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 5D4→7F5 emission was observed with lifetimes of ~5 ns and 6.35 ms.