Hydrothermal synthesis and luminescent properties of Ca3(PO4)2: Dy3+ white-emitting phosphors

The white-emitting Ca-3(PO4)(2): Dy3+ phosphors were prepared via hydrothermal synthesis. The phosphors were characterized by XRD, TEM, SEM, EDS, GSAS structural refinement and PL spectroscopy, respectively. Rietveld refinement demonstrated that the Ca-3(PO4)(2) crystal structure consisted of [PO4] tetrahedrons filled with Ca atoms. Dy3+ ions occupied high-symmetry sites due to the emission intensity of F-4(9/2) -> H-6(15/2) was strongest. Moreover, the pH value and calcination temperature had important effects on the phosphor morphology and luminescent properties. The morphology of the samples changed from long-rod to short-rod and sphere and the size reduced as the pH value in the initial reaction solution increased. The samples with pH of 7 had the best luminescence properties, and the precursor before calcination corresponded to Ca4P2O9. With the calcination temperature of the precursor with pH of 7 increased, the phosphor morphology changed from nanorods to grains with diameters of about 1 mu m, and the luminescence properties were improved continuously. The CIE coordinate of Ca-3(PO4)(2): Dy3+ phosphor was (0.283, 0.343). The Ca-3(PO4)(2): Dy3+ phosphor has better application prospects for white light-emitting diodes. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

White-emitting Ca-3(PO4)(2): Dy3+ phosphors were synthesized via hydrothermal method. The pH value and calcination temperature significantly influenced the phosphor morphology and luminescent properties, with samples at pH 7 exhibiting the best luminescence properties.