Li_2O－Ln_2O_3－SiO_2：Eu^（3＋），Bi^（3＋）体系的结构

RELATIONSHIP BETWEEN THE STRUCTURE AND LUMINESCENCE PROPERTIES OF THE SYSTEM Li_2O-Ln_2O_3-SiO_2: Eu￣(3+), Bi￣(3+)(Ln = Y, Gd, La)

采用ｓｏｌ－ｇｅｌ法合成了系列发光体Ｌｉ２Ｏ－Ｌｎ２Ｏ３－ＳｉＯ２：Ｅｕ３＋，Ｂｉ３＋，并确定了发光体的物相结构．当Ｌｎ３＋＝Ｙ３＋和Ｌｎ３＋＝Ｌａ３＋时，紫外光激发下Ｅｕ３＋的发射分别以红光和橙光为主，只存在一种Ｅｕ３＋发光中心；Ｌｎ３＋＝Ｇｄ３＋时，至少存在两种Ｅｕ３＋发光中心和两种Ｂｉ３＋发光中心（共掺杂Ｅｕ３＋，Ｂｉ３＋），Ｂｉ３＋的吸收和发射所处的能量位置最低，４ｆ格位的Ｂｉ３＋发生了向Ｅｕ３＋的有效能量传递．

The series silicate luminophors Li2O-Ln2O3-SiO2: Eu3+,Bi3+ were synthesized by sol-gel method, and their phase and structure were determined by XRD. Under the excitation of UV light, Eu3+ ions show red emission and orange emission in the case of Ln3+=Y3+ and Ln3+= La3+, respectively, in which two hosts exist only one Eu3+luminescent center. Nevertheless when Ln3+= Gd3+, at least two kinds of Eu3+and Bi3+ ions luminescent centers were observed. Bi3+has lower excitation and emission energies due to the stronger covalency for Ln3+=Gd3+, in which host an efficient energy transfer from Bi3+at 4f sites to Eu3+has been found.