BaCl_xBr_(2-x)∶Eu^(2+)材料光激励光谱及色心研究

Photostimulated Luminescence and Color Centers Research in BaCl_xBr_(2-x)∶Eu^(2+) Phosphors

采用高温固相法制备了BaClxBr2-x∶Eu2+光激励发光材料,利用XRD、激发、发射以及激励光谱研究了所制备材料的结构和光学性能。XRD图像表明所制备的材料为单一纯相,随X值增大,衍射角向大角度偏移。发射光谱中位于405nm的窄带谱峰,由Eu2+的4f65d→4f7能级跃迁所引起,监测405nm发射峰,所得激发光谱是位于250～380nm之间的宽带,谱峰位于303nm;光激励波段位于480～800nm,激励峰位于575nm。通过光谱曲线拟合,发现激励光谱由550,610和685nm左右的光谱叠加而成,分别对应F(Cl-),F(Cl-Br),F(Br-)色心,激励峰随Cl/Br比值增加而蓝移。

Eu2＋ doped BaClxBr2-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 that the samples are single phase of BaClxBr2-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 4f65d→4f7. The excitation spectrum excited by 405 nm is a broad band ranging from 250-380 um 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（CI- ）, F（CI-Br） and F（Br- ）centers, respectively. The photostimulation peaks show a blue shift with increasing the ratio of CI/Br.