The photoluminescence properties of dendritic phosphors Ca₂Gd₈(SiO₄)₆O₂:A (A = Eu³⁺ and Dy³⁺) for white-light-emitting diodes

Ca₂Gd₈(SiO₄)₆O₂:A (A = Eu³⁺ and Dy³⁺) phosphors were successfully synthesized by the sol. gel process. X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the diffraction peaks of the phosphor powder agreed well with the standard card. Under short ultraviolet excitation, the doped rare earth ions (A) showed their characteristic emissions in Ca₂Gd₈(SiO₄)₆O₂ phophors, i.e., ⁵D₀→⁷F₂ (615 nm) for Eu³⁺ and ⁴F_9/2→⁶H_15/2 (483 nm) and ⁴F_9/2 →⁶H_13/2 (575 nm) for Dy³⁺. The optimum concentration for doped rare earth ions was determined to be 9 mol% Eu³⁺ and 3 mol% Dy³⁺ of Gd³⁺ in Ca₂Gd₈(SiO₄)₆O₂.