摘要
采用高温固相反应法分别合成了变价稀土镨和镱离子掺杂的绿色荧光粉[Ba(2-n-1.5x)REx]SiO4∶nEu2+(n=0.03,RE=Pr,Yb;x=0,0.02,0.05,0.10)。结果表明:所有合成荧光粉的激发峰均为250~400 nm的宽峰,与近紫外LED的发射光波长相匹配。发射峰位于450~550 nm之间,是Eu2+的5d-4f跃迁的典型发射。Pr3+和Yb3+的掺入并未改变Ba2SiO4∶Eu2+的相组成,但对荧光强度的影响大,且与掺杂元素、掺杂量和煅烧温度相关。当掺杂Pr3+和Yb3+的量为x=0.02时,经1150℃煅烧所得荧光粉的发光强度分别是未掺杂时的595%和168%。证明三价稀土离子掺杂可以导致基质中的电荷缺陷而敏化Eu2+离子的发光,而变价稀土离子的掺杂可以大大提高电荷缺陷,导致荧光强度的进一步提高。
[Ba（2-n-1.5x） REx]SiO4： nEu^2＋ （ n = 0.03, RE = Pr, Yb; x = O, 0.02, 0.05, 0.10） phosphors were prepared by conventional solid-state high temperature reaction in reductive atmosphere. The results showed that the excitation and emission peaks of all the as-synthesized phosphors were wide bands. The excitation band ranged from 250 nm to 400 nm, which matched the wavelength of near ultraviolet LED chip well, could be used as a potential candidate for the fabrication of white LED. The emission band from 450 to 550 nm was typical 5d-4f transition emission of Eu^2＋ and displayed un-symmetry profiles due to the two substitution sites of Ba^2＋ by Eu^2＋. The co-doping of Yb or Pr greatly enhanced the fluorescence intensity of BaESiO4： Eu^2＋ phosphors without change of crystalline phase. The fluorescence intensities of as-synthesized phosphors depended on species and amount of doping elements, as well as the calcinations temperature. The fluorescence intensity of BazSiO4： Eu^2＋ phosphors doped with x =0.2 of Pr or Yb were 595% and 168% as high as that of BaESiO4： Eu^2＋ phosphor calcined at the same temperature of 1150 ℃. These facts demonstrated that it was the charge defects originated from the co-doping of rare earth ions that resulted in the significant enhancement of fluorescence intensity of the phosphors, and the doping of rare earth elements with variable valence could greatly increase the charge defects.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2009年第1期36-39,共4页
Journal of the Chinese Society of Rare Earths
基金
教育部长江学者与创新团队发展计划项目(IRT0730)
江西省主要学科带头人和省科技厅工业攻关计划资助项目
