Li_2BaSiO_4:Sm^(3+)荧光粉的制备与性能研究

Synthesis and Properties of Li_2BaSiO_4:Sm^(3+) Phosphor

采用高温固相法合成Li2Ba Si O4:Sm3+荧光粉,X-射线衍射(XRD)结果表明,850oC高温制备的Li2Ba Si O4∶Sm3+为六方晶系结构,随着Sm3+掺入量增加,衍射峰向大角度方向偏移,晶格畸变增加。该材料在330~500 nm处有很强的吸收,能被近紫外光和蓝光发光二极管(LED)有效激发,当Sm3+质量分数为1.5%时发光强度最大,且I650/I607比值最小,表明Sm3+优先进入Li2Ba Si O4对称格位。在402 nm激发时,发出518、563、607、650和707 nm发射峰,其中518 nm来源于Li2Ba Si O4∶Sm3+缺陷发光,其他4个峰来源于Sm3+的4G5/2→6HJ(J=5/2,7/2,9/2,11/2)发光。由于缺陷发光,Li2Ba Si O4∶Sm3+的色坐标位于黄光区域,并分析了缺陷发光机理。

Sm^3＋-doped Li2BaSiO4∶Sm^3＋phosphor is prepared by a solid-state reaction method. Through X-ray diffraction（XRD） data, Li2 Ba Si O4∶Sm^3 ＋with hexagonal crystal structure is synthesized at 850 oC, and the diffraction peak of XRD move to the high-angle and the lattice distortion increase as increasing the mass fraction of Sm^3 ＋ions. The Li2 Ba Si O4∶Sm3 ＋material has strong absorption at 330~500 nm and can be excited effectively by near ultraviolet and blue light emitting diode（LED） chip. The maximum emission intensity of Sm^3＋and the minimum ratio of I650/I607 are attained by doping 1.5% Sm^3＋. The results suggest that Sm3＋ions prior to occupy Ba2 ＋with symmetric lattice in the Li2 Ba Si O4 materials. The emission peaks located at 518, 563, 607,650 and 707 nm are presented under the excitation of 402 nm. The spectrum of 518 nm is attributed to defect luminescence in Li2 Ba Si O4∶Sm^3＋, while others are derived from the emission of4G5/2→6HJ（J=5/2,7/2,9/2,11/2） of Sm^3 ＋. The color coordinate of Li2 Ba Si O4∶Sm^3 ＋sites in yellow range due to defect emission, and the formation mechanism for defect luminescence is discussed.