Tuning of crystal phase and luminescence properties of Gd2(MoO4)3:Dy3+ phosphors

The orthorhombic and monoclinic Gd2(MoO4)3:Dy3+ were successfully synthesized by a hydrothermal process with a subsequent annealing treatment at 800 °C for 4 h. The crystal phase of Gd2(MoO4)3:Dy3+ was controlled as a function of the pH value of the solution. The crystallization and microstructures of the samples were characterized by Powder X-ray diffraction (XRD) and scanning electron micrograph (SEM). Furthermore, the optical properties were investigated by the diffuse reflection, excitation and emission spectra. The mechanisms of different crystal phases affected on the luminescence properties of Gd2(MoO4)3:Dy3+ were discussed. The electric dipole–dipole interaction between Dy3+ ions was identified as the main mechanism for the concentration quenching of the two structures. Finally, the chromatic natures of all the samples were analyzed in detail. The results indicate that the orthorhombic phosphor Gd1.84(MoO4)3:Dy0.163+ can be considered as a suitable candidate for white light emitting diodes (W-LEDs).

The optical properties of Dy3+ were found to be sensitive to the crystal phase of the as-synthesized Gd2(MoO4)3:Dy3+ phosphors, especially the distinct features of the charge transfer (CT) transition. The mechanism involved was discussed in detail based on the experiments and theoretic calculations.Figure optionsDownload as PowerPoint slideHighlights
► The crystal phase of Gd2(MoO4)3:Dy3+ was tuned by changing the pH value of the solution in hydrothermal system.
► The optical properties of Dy3+ were found to be sensitive to the crystal phase of Gd2(MoO4)3:Dy3+.
► The mechanisms of different crystal phases affected on the luminescence properties of Gd2(MoO4)3:Dy3+ were discussed.