Synthesis, photoluminescence properties and thermal investigation by TG-MS of RE(DAS)3·xH2O (RE = Eu3+, Tb3+)

Abstract

Rare earth (III) diphenyl-4-amine sulfonates (RE(DAS)3·xH2O, RE = Eu3+, Tb3+) phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates. FTIR, TG/DSC coupled to mass spectrometry (TG/DSC/MS), X-ray powder diffraction (XPD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy were utilized to structurally and morphologically characterize the samples. Thermal decomposition of Eu(DAS)3·7H2O and Tb(DAS)3·2H2O at 973 K under dynamic air atmosphere results in crystalline Eu2O2SO4 and Tb2O2SO4 materials, respectively. Accordingly, MS spectra reveal the liberation of thermal decomposition products of precursors, largely as CO2, NO2 and SO2 gases. The diphenyl-4-amine sulfonate (DAS) ligand demonstrats a good stabilizing property for Eu3+ and Tb3+ ions. The Eu(DAS)3·7H2O and Tb(DAS)3·2H2O compounds display efficient red and green emissions, under UV excitation, arising from the 5D0 → 7FJ (J = 0–4) and 5D4 → 7FJ (J = 0–6) transitions of the Eu3+ and Tb3+ ions, respectively.