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Y2O3:Eu3+,Tb3+,Ce3+ phosphors were prepared by the co-precipitation method and the optimal component formulations of the samples were determined by a combination of controlled variable method and orthogonal experiments. The experimental results show that doping with appropriate amounts of Tb3+ and Ce3+ significantly improved the luminescence performance of Y2O3:Eu3+ phosphors. In the Y2O3:Eu3+,Tb3+,Ce3+ phosphors system, Tb3+ could be used as a carrier to transfer energy for Ce3+–Eu3+, eliminating the presence of metal–metal charge transfer (MMCT) between the two ions. The direction of energy transfer which is from Ce3+ → Tb3+ → Eu3+ has been confirmed by emission spectrum and calculation results show that the mechanism of Tb3+ to Eu3+ energy transfer and Ce3+ to Tb3+ energy transfer in Y2O3 matrix are both quaternary–quaternary interactions. As the doping concentration of Tb3+ and Ce3+ increases, the emission peak position of phosphor was shifted toward the blue region. Their structure and micromorphology have been analyzed by X-ray diffraction and scanning electron microscopy, the test results show that ion doping does not cause changes in the crystal structure of Y2O3 and the samples are approximately spherical in shape. This work provides a new idea to study the UV detection and multi-ion inter-energy transfer model. [ABSTRACT FROM AUTHOR]

The red-emitting Ca9Eu(PO4)7 nanophosphors have been successfully synthesized by a facile hydrothermal method. X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, GSAS structural refinement and scanning electron microscopy (SEM) were used to characterize the materials. Rietveld refinement of powder X-ray diffraction patterns of Ca9Eu(PO4)7 demonstrated that the structure of Ca9Eu(PO4)7 consisted of [PO4] tetrahedra. Ca/Eu atoms filled the space between the tetrahedral groups with Eu3+ ions distributed randomly on three individual Ca crystallographic sites. The major red emission peak located at 616 nm under 397 nm excitation attributed to the electric dipole transition 5D0→7F2 of Eu3+ was a parity forbidden f–f configuration transition, which would only occur when Eu3+ occupied lattice sites without inversion symmetry. Introducing Gd, La, and Y ions into samples made luminescence properties of Ca9Eu1−xLnx(PO4)7 (Ln = Gd, La, Y) phosphors decrease. pH value plays a key role in the formation of Ca9Eu(PO4)7 nanophosphor morphology. With increasing pH in the initial reaction solution, the morphology of samples changed from rod to sphere and their aspect ratio also decreased. Different morphologies have different photoluminescence properties, and samples prepared at pH 7 manifested better photoluminescence properties relative to other samples. This novel red-emitting phosphor could be applied in white light-emitting diodes. [ABSTRACT FROM AUTHOR]