采用固相法制备了绿色LiM(M=Ca,Sr,Ba)BO3∶Tb^3+发光材料。测量结果显示材料均可被紫外(350~410nm)光激发,发射绿光。研究了Tb^3+浓度对材料发射光谱的影响,结果显示,随Tb3+浓度的增大,发射光谱峰位未发生变化,但其强度呈现出先增大后减小的趋势,即:存在浓度猝灭效应。加入电荷补偿剂Li^+,Na^+和K^+提高了LiM(M=Ca,Sr,Ba)BO3∶Tb^3+材料的发射强度。
LiM(M=Ca,Sr,Ba)BO3∶Tb^3+ phosphors were synthesized by solid state reaction. The starting materials CaCO3,SrCO3,BaCO3,H3BO3,Li2CO3,Na2CO3,K2CO3 and Tb4O7 (99.99% in mass) in appropriate stoichiometric ratio were mixed in the alumina crucible,then the mixed powders were calcined at 700 ℃ for 2 h,and LiCaBO3∶Tb^3+,LiSrBO3∶Tb^3+ and LiBaBO3∶Tb^3+ phosphors were obtained. The emission and excitation spectra were measured by a Shimadzu RF-540 ultraviolet spectrophotometer. All the photoluminescence properties of these phosphors were measured at room temperature. The emission spectra of LiM(M=Ca,Sr,Ba)BO3∶Tb^3+ phosphors show several bands,and the main emission peaks correspond to the ^5D4→^7F6(486,486,488 nm),^5D4→^7F5(544,544,544 nm),^5D4→^7F4(590,595,593 nm) and ^5D4→^7F3(620,620,616 nm) typical transitions of Tb^3+,and the typical transitions of Tb^3+ happens to split because of the effects of LiM(M=Ca,Sr,Ba)BO3 crystals field. The excitation spectra for the 544 nm green emission of LiM(M=Ca,Sr,Ba)BO3∶Tb^3+ phosphors illuminate that these kinds of phosphors can be effectively excited by ultraviolet (350-410 nm) light,and emit green light,therefore,they are promising phosphors for white light emitting diodes. Effects of activation and charge compensation on the luminescence intensities of LiM(M=Ca,Sr,Ba)BO3∶Tb^3+ phosphors were studied,and the results show that the intensities were obviously effected.