La4(P2O7)3：Ce,Gd,Tb磷光体的合成与光谱性质

本文首次采用溶液沉淀法合成了一系列La4(P2O7)3;Ce,Gd,Tb磷光体.经X射线分析表明,它们属于纯的La4(P2O7)3相。测定了这些化合物的激发和发射光谱、相对亮度及Ce3+的发光寿命,观察到在此基质中Ce3+与Gd3+的光谱重叠,它们之间存在着一定的相互作用,使(La0.64Ce0.3Gd0.064(P2O7)3的亮度比(La0.7Ce0.34(P2O7)3和(La0.94Gd0.064(P2O7)3有少许增加.此外,Ce3+能有效地敏化Tb3+9,从而大大增强Tb3+的发射.然而,Gd3+与Tb3+共存时存在着竞争吸收和独自发射,使(La0.80Gd0.06Tb0.144(P2O7)3的亮度与单掺的(La0.86Tb0.144(P2O7)3相比有少许降低.相应地在Ce,Gd和Tb共掺时,由于Gd3+的影响,使Tb3+的发射减弱,从而总的发光相对亮度有所降低。

PREPARATION AND SPECTROSCOPIC PROPERTIES OF La_4 (P_2O_7)_3:Ce,Gd,Tb PHOSPHORS

A series of La4(P2O7)3:Ce,Gd,Tb phosphors have been prepared by precipitation from aqueous solution and subsequent ignition.XRD measurements confirm that the products are pure phase La4(P2O7)3. Excitation and emission spectra,relative brightness and cerium luminescence lifetime of these phosphors have been obtained.It is shown that in the crystalline lattice of La4(P2O7)3,the spectra of Ce and Gd overlap with each other, rendering certain interaction to occur between them and hence bringing about some increase of brightness of (La0.64Ce0.3Gd0.06)4(P2O7)3 as compared to either (La0.7Ce0.3)4(P2O7)3 or(La0.94Gd0.06)4(P2O7)3.On the other hand,Ce effectively sensitizes Tb, enhancing the Tb emission considerably.However,the coexislance of Gd and Tb gives rise to competitive absorption and individual emission, rendering a slight decrease of the brightness of(La0.80Gd0.06Tb0.14)4(P2O7)3 as compared to that of singly doped(La0.86Tb0.14)4(P2O7)3.Consequently in the case of codoping of Ce, Gd,and Tb,the emission is also weakened.