Rapid Production of Ln2O2S:Eu3+/Tb3+ (Ln = Sm, La, Gd, and Y) Phosphors by Molten Salt Electrolysis

In this paper, a facile one-pot molten salt electrolysis method has been proposed for the synthesis of hexagonal sheet-like Ln2O2S:Eu3+/Tb3+ (Ln = Sm, La, Gd and Y) phosphors. The phase, composition, morphology, and optical properties of the phosphors were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and photoluminescence. The results showed that doping Eu3+ or Tb3+ causes no great changes to the crystal structure. Under the excitation of 394 nm light, sheet-like Ln2O2S:Eu3+ (Ln = Sm, La, Gd, and Y) exhibited predominantly red emission at around 627 nm, which corresponds to the absorption of host crystals and the energy level transitions of 5D0 to 7F2 configuration of Eu3+ ions. The sheet-like Ln2O2S:Tb3+ exhibited characteristic excitation of Tb3+ under 364 nm. The emission spectra of Ln2O2S:Tb3+ (Ln = Sm, La, Gd, and Y) were measured, and those emission lines between 450 and 650 nm corresponded to the transitions of 5D4 to 7FJ (J = 0–6) groun...