Kinetic parameters and luminescence properties of rare earth (Tb, Nd) doped and transition metal (Mn) doped/co-doped YAlO3 prepared via sol-gel method

Abstract

In this work, phosphor materials with the formula YAlO3 were synthesized via sol-gel method by using the stoichiometric amounts of yttrium nitrate and aluminum nitrate as base materials. The obtained phosphors were doped/co-doped with Tb3+, Nd3+ rare earth ions and Mn2+ transition metal ion. For evaluating the influence of the dopants, the grain size and morphology of the samples by scanning electron microscopy (SEM) and the phase and crystallinity of the synthesized materials by X-ray diffraction (XRD) were investigated. Optical absorption spectra, photoluminescence (PL) and thermoluminescence (TL) were performed to determine a relationship the changing dopant on luminescence properties of YAlO3. Moreover, the kinetic parameters namely activation energy (E), order of kinetics (b) and frequency factor (s) of the synthesized pure and doped materials were calculated using Computerized Glow Curve Deconvolution (CGCD) and Peak Shape Method for a better understanding of the optical properties that change with the doping process. Strong green emission was detected in the sample doped with Mn2+ correspond to 4T1(G)→6A1(S) transition. As for YAlO3: Nd3+, characteristic emissions originated from 4G11/2 → 4I9/2 (∼423 nm), 4G9/2 → 4I9/2 (∼460 nm) and 4G7/2 → 4I9/2 (∼540 nm) transitions were seen. The optical band gap of undoped sample was calculated as 2.79 eV and depending on the presence of Nd3+ and Tb3+ dopant ions this value was decreased to the range 2.46–2.56 eV.