Pr^（3＋）掺杂的Cd_3M_2Ge_3O_（12）（M＝Al，Ga）石榴石

CATHODOLUMINESCENCE PROPERTIES OF Pr￣(3+) DOPED GERMANATE GARNET

首次报道Ｐｒ￣（３＋）分别激活的Ｃｄ＿３Ａｌ＿２Ｇｅ＿３Ｏ＿（１２）（ＣＡＧＧ）和Ｃｄ＿３Ｇａ＿２Ｇｇｅ＿３Ｏ＿（１２）（ＣＧＧＧ）锗酸盐石榴石的阴极射线发光光谱，Ｐｒ￣（３＋）的４ｆ能级发射强度与ｐｒ￣（３＋）浓度关系以及粉红色较长余辉特性。与ＣＡＧＧ相比，发现在ＣＧＧＧ中Ｐｒ￣（３＋）的所有４ｆ－４ｆ跃迁发射峰位置向短波移动，并分析造成这种光谱“蓝移”的原因。

The cathodoluminescence properties of Pr￣(3+) doped Cd_3Al_2Ge_3O_912) and Cd_3Ga_2Ge_3O_(12) germanate garnets are reported for the first time,the emission intensity of(blue)and(red)transitions depends on Pr￣(3+) concentration。The Cd_3M_2Ge_3O_(12)(M= Al,Ga) phosphors exhibit the longer persistence with the pink colour after the cathode ray excitation is turned off.The cathodoluminesecence(CL)spectra of CAGG:Pr￣(3+) and CGGG:pr￣(3+) phosphors observed at RT consist of the emission band of germanate host and charac- teristic emission lines of 4f-4f transition of Pr￣(3+) ion respectively. The emission peaks of the Pr￣(3+) in Cd_3Ga_2Ge_3O_(12) shift in the direction of shorter wavelength and emission of the level transition is de- creased.The spectral shift may be explained that it is due to the difference in the electronegativity of element,for Ga=1. 6 and Al=1.5,and in covalent bonding in the two germanate garnets.It is known that the higher the electronegativity of the element,the lower is the covalency and nephelauxetic effect,the centre of the gravityin energy of the J levels shift:to the higher position。As a consequence,the absorption and ernission spectra shift in the direction of shorter wavelength.