Physical and optical studies of Gd2O2S:Eu3+ nanophosphors by microwave irradiation and γ‐irradiation methods

Gd₂O₂S:Eu³⁺ nanophosphors have been successfully synthesized using microwave irradiation and γ‐irradiation methods with polyvinyl pyrrolidone as a stabilizer. The physical and luminescence spectra were compared. The morphologies of both Gd₂O₂S:Eu³⁺ nanophosphors were in the hexagonal phase and mainly consisted of spherical nanostructures with diameters of ~90 nm and ~50 nm for both microwave irradiation and γ‐irradiation methods. Upon 325 nm of ultraviolet (UV) light excitation, strong red emissions (626 nm) were observed for both methods; these emissions corresponded to the ⁵D₀→⁷F₂ transition of Eu³⁺ ions. However, Gd₂O₂S:Eu³⁺ nanophosphors following microwave treatment showed better luminescence intensity than Gd₂O₂S:Eu³⁺ nanophosphors treated with γ‐irradiation. This difference was attributed to the crystallinity phase and surface quenching effects of Gd₂O₂S:Eu³⁺ nanophosphors. The reaction mechanisms of Gd₂O₂S:Eu³⁺ nanophosphors in both methods are discussed in detail.