[Photostimulated luminescence and color centers research in BaCl(x)Br(2-x):Eu2+ phosphors]

Eu2+ doped BaCl(x)Br(2-x), phosphors were prepared by solid state method in the present paper. The crystal structure and luminescent properties were studied by XRD, excitation, emission, and photostimulation. The XRD patterns indicate thatthe samples are single phase of BaCl(x)Br(2-x). The X-ray diffraction peak shifts to larger angle as the value of X increases. The emission spectra is a narrow band with a peak locating at 405 nm, which is attributed to the transition of 4f(6)5d-->4f(7). The excitation spectrum excited by 405 nm is a broad band ranging from 250-380 nm with a peak locating at 303 nm. The photostimulation spectrum is a broad band ranging from 480-800 nm with a peak locating at 575 nm. Through fitting the spectrum curve, the photostimulation spectrum is composed of three bands with peaks locating at about 550, 610 and 685 nm. The three fitting bands correspond to the three color-centers belonging to F(Cl-), F(C1-Br) and F(Br-) centers, respectively. The photostimulation peaks show a blue shift with increasing the ratio of Cl/Br.