论文部分内容阅读
Long afterglow phosphors MAl_2O_4∶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 CaAl_2O_4∶Eu~ 2+, Dy~ 3+ and SrAl_2O_4∶Eu~ 2+, Dy~ 3+ are with monoclinic crystal structure and phosphor BaAl_2O_4∶Eu~ 2+, Dy~ 3+ is with hexagonal crystal structure. The wide range of excitation spectrum of phosphors MAl_2O_4∶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 MAl_2O_4∶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.
Long afterglow phosphors MAl 2 O 4: 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 CaAl 2 O 4: Eu ~ 2+, Dy ~ 3+ and SrAl_2O_4:Eu ~ 2+, Dy ~ 3+ are with monoclinic crystal structure and phosphor BaAl_2O_4: Eu ~ 2+, Dy ~ 3+ is with hexagonal crystal structure. spectrum of phosphors MAl_2O_4: Eu ~ 2+, Dy ~ 3+ (M = Ca, Sr, Ba) indicates that the luminescent materials can be excited by light from ultraviolet rays to visible light and the maximum emission wavelength of phosphors MAl_2O_4: Eu ~ (M = Ca), 520 nm (M = Sr) and 496 nm (M = Ba), respectively 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 transitio nal 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.