Crystal structure and luminescent property of flaky-shaped Sr4Al14O25:Eu2+, Dy3+ phosphor doped with Er3+ ions

Abstract In this study, the afterglow properties of Sr 4 Al 14 O 25 :Eu 2+ , Dy 3+ was successfully improved and the absorption in the visible region (>400 nm) was increased using co-doped Er 3+ ions, thus facilitating the application of Sr 4 Al 14 O 25 :Eu 2+ , Dy 3+ in daylight environment. A series of Sr 3.88−x Al 14 O 25 :0.04Eu 2+ , 0.08Dy 3+ , xEr 3+ (x = 0, 0.04, 0.08, 0.12, 0.16, and 0.20) phosphors were prepared using a conventional high-temperature solid-phase method; their structures were characterized by XRD, TEM, HRTEM, FT-IR, and XPS. The luminescence properties, with excitation at 275 nm and 360 nm, were systematically compared and analyzed by fluorescence spectra, afterglow spectra, and afterglow decay spectra. Interestingly, although the Er 3+ doping slightly affected the crystal structure of Sr 4 Al 14 O 25 :Eu 2+ , Dy 3+ phosphor, the luminescent properties of phosphors were affected to a large extent. After the Er 3+ doping, the emission peak of Eu 2+ at 485 nm split into three peaks at 481 nm, 492 nm, and 529 nm. An appropriate Er 3+ doping significantly enhanced the afterglow performance of the phosphors, whereas excessive Er 3+ doping caused concentration quenching. The absorption in the visible region (>400 nm) increased with Er 3+ doping, which was more suitable for the application of Sr 4 Al 14 O 25 :Eu 2+ , Dy 3+ in daylight environment. The initial afterglow intensities with 360 nm excitation were higher than those with 275 nm excitation, whereas the afterglow time of the former was slightly shorter than that of the later. The one-dimensional and two-dimensional lattice fringe phase of the local particles can be observed clearly from HRTEM of flaky-shaped Sr 3.76 Al 14 O 25 :0.04Eu 2+ , 0.08Dy 3+ , 0.12Er 3+ particle, which was rare in the previous reports. Moreover, the preliminarily enhancing mechanism of Er 3+ on the luminescent properties of Sr 3.88 Al 14 O 25 :0.04Eu 2+ , 0.08Dy 3+ phosphor was analyzed.