Synthesis of Long Afterglow Phosphors MAl₂O₄∶Eu²⁺, Dy （3+）（M=Ca, Sr, Ba） by Microemulsion Method and Their Luminescent Properties

【Abstract】 Long afterglow phosphors MAl₂O₄∶Eu 2+, Dy 3+ （M=Ca, Sr, Ba） were synthesized by microemulsion method, and their crystal structure and luminescent properties were compared and investigated. XRD patterns of samples indicate that phosphors CaAl₂O₄∶Eu 2+, Dy 3+ and SrAl₂O₄∶Eu 2+, Dy 3+ are with monoclinic crystal structure and phosphor BaAl₂O₄∶Eu 2+, Dy 3+ is with hexagonal crystal structure. The wide range of excitation spectrum of phosphors MAl₂O₄∶Eu 2+, Dy 3+ （M=Ca,Sr,Ba） indicates that the luminescent materials can be excited by light from ultraviolet ray to visible light and the maximum emission wavelength of phosphors MAl₂O₄∶Eu 2+, Dy 3+ （M=Ca, Sr, Ba） is found mainly at λ em of 440 nm （M=Ca）, 520 nm （M=Sr） and 496 nm （M=Ba） respectively, the corresponding colors of emission light are blue, green and cyna-green respectively. The afterglow decay tendency of phosphors can be summarized as three processes: initial rapid decay, intermediate transitional decay and very long slow decay. Afterglow decay curves coincide with formula I=At -n, and the sequence of afterglow intensity and time is Sr>Ca>Ba.更多还原