Luminescence characteristics and kinetic parameters of LiBaPO4: Tb3+, Dy3+ phosphors synthesized by sol-gel method

Abstract

LiBaPO<inf>4</inf>: Tb3+, Dy3+ phosphors were prepared via sol-gel method by using the stoichiometric amounts of lithium nitrate LiNO<inf>3,</inf> barium nitrate Ba(NO<inf>3</inf>)<inf>2</inf> and ammonium dihydrogen phosphate NH<inf>4</inf>H<inf>2</inf>PO<inf>4</inf> as base materials. Morphology by scanning electron microscopy (SEM), structure by X-ray diffraction (XRD), thermal properties by Differential thermal analysis (DTA)/Thermogravimetric Analysis (TGA) and structural characteristics by Fourier transform infrared spectroscopy (FT-IR) were investigated. This paper presents luminescence properties using spectra from radioluminescence (RL), photoluminescence (PL), cathodoluminescence (CL) and, thermoluminescence (TL) and the influence of RE dopants (Tb3+, Dy3+) on the luminescent behavior of LiBaPO<inf>4</inf>. Computerized Glow Curve Deconvolution (CGCD) and Peak Shape Method were used to determine the kinetic parameters and the obtained results were evaluated. The RL results of un-doped LiBaPO<inf>4</inf> showed the presence of a well-defined peak at 417 nm and a weaker band around 685 nm. Strong emissions were detected in the sample doped with Dy3+ correspond to 4F<inf>9/2</inf>?6H<inf>j</inf> transitions. Blue, yellow and red emissions were observed with transitions of 4F<inf>9/2</inf> ? 6H<inf>15/2</inf>, 4F<inf>9/2</inf> ? 6H<inf>13/2</inf> and 4F<inf>9/2</inf> ? 6H<inf>11/2</inf>, respectively. As for LiBaPO<inf>4</inf>: Tb3+, green emissions originated from the characteristic transitions (5D<inf>3</inf> ? 7F<inf>J</inf> (j = 6–3) and 5D<inf>4</inf> ? 7F<inf>J</inf> (j = 6–1)) of Tb+3 ion was seen. The RL, PL and CL spectra were identical, suggesting these green emissions. Dy3+ doped sample has three glow curves located at 72 °C, 145 °C and 204 °C, while the main temperature peak is measured at 240 °C for Tb3+ doped sample. Chromotographic studies of LiBa<inf>0·98</inf>PO<inf>4</inf>: Dy3+<inf>0.02</inf> reveals that calculated x and y color coordinates (0.3122, 0.3233) are very close to the white light. © 2023