A novel strategy to synthesize Gd₂O₂S:Eu³⁺ luminescent nanobelts via inheriting the morphology of precursor

Gd₂O₃:Eu³⁺ nanobelts were fabricated by calcination of the electrospun PVP/[Gd(NO₃)₃ + Eu(NO₃)₃] composite nanobelts. For the first time, Gd₂O₂S:Eu³⁺ nanobelts were successfully prepared via inheriting the morphology and sulfurization of the as-prepared Gd₂O₃:Eu³⁺ nanobelts precursor using sulfur powders as sulfur source by a double-crucible method we newly proposed. X-ray diffraction analysis indicated that Gd₂O₂S:Eu³⁺ nanobelts were pure hexagonal in structure with space group P\( \bar{3} \) m1. Scanning electron microscope analysis results showed that the width and thickness of the Gd₂O₂S:Eu³⁺ nanobelts were ca. 2.1 μm and 129 nm, respectively. Under the excitation of 330-nm ultraviolet light, Gd₂O₂S:Eu³⁺ nanobelts emitted red emissions of predominant peaks at 628 and 618 nm which were attributed to the ⁵D₀ → ⁷F₂ energy levels transitions of the Eu³⁺ ions. It was found that the optimum doping molar concentration of Eu³⁺ ions in Gd₂O₂S:Eu³⁺ nanobelts was 5 %. Possible formation and sulfurization mechanisms of Gd₂O₂S:Eu³⁺ nanobelts were also proposed. This new sulfurization technique is of great importance, not only can inherit the morphology of rare earth oxides, but also can fabricate pure-phase rare earth oxysulfides at low temperature compared with conventional sulfurization method.