Preparation And Luminescence Properties Of Dy³⁺/Eu³⁺doped Glass-ceramics Containing NaGd（WO₄）₂

In this paper,Dy³⁺,Eu³⁺single-doped and Dy³⁺-Eu³⁺double-doped transparent glass ceramics containing Na Gd（WO₄）₂ crystal phase were prepared by the melting-crystallization method.Through the analysis of X-ray diffraction pattern,it is confirmed that the crystal phase of Na Gd（WO₄）₂ precipitates in glass-ceramics.Scanning electron microscope images show that the grains increase and grow with the increase of heat treatment time,and the contact phenomenon occurs when the heat treatment time is longer.Through the analysis of the optical transmittance curve,it is found that the optical transmittance decreases with the increase of heat treatment time.Combining X-ray diffraction,scanning electron micrographs and transmittance curve analysis,which is determined that the best heat treatment condition for Dy³⁺single-doped,Eu³⁺single-doped and Dy³⁺-Eu³⁺double-doped precursor glass were560℃for 2 h,570℃for 2 h and 560℃for 2 h,respectively.The excitation and emission spectra were used to discuss the luminous intensity of glass-ceramics when Dy³⁺and Eu³⁺were doped with different concentrations.The optimal doping percentages of Dy³⁺and Eu³⁺single doping was determined to be 0.8%and 0.9%,respectively,and the optimal doping percentages of Dy³⁺-Eu³⁺double doping were 0.8%-0.8%.Dy³⁺and Eu³⁺single-doped glass-ceramics containing Na Gd（WO₄）₂crystal phase can realize white light and red light emission,respectively.The fluorescence lifetimes of Dy³⁺,Eu³⁺single-doped and Dy³⁺-Eu³⁺double-doped glass ceramic samples were calculated.By analyzing the fluorescence spectrum and fluorescence lifetime curve of Dy³⁺-Eu³⁺co-doped glass ceramic samples,it is found that there is an energy transfer phenomenon between Dy³⁺and Eu³⁺,and the energy transfer efficiency is calculated.Under certain conditions,Dy³⁺-Eu³⁺co-doped glass ceramics can achieve warm white light emission.The critical distances between rare earth ions in Dy³⁺,Eu³⁺single-doped and Dy³⁺-Eu³⁺double-doped glass-ceramics were calculated,and the energy transfer mechanism between rare earth ions was studied.It shows that Dy³⁺/Eu³⁺doped glass-ceramics containing Na Gd（WO₄）₂ crystal phase have potential applications in the W-LED field.