纳米微晶X_1-Y_2SiO_5: Eu中两种发光中心之间的能量传递研究

INVESTIGATION ON ENERGY TRANSFER BETWEEN THE TWO SITES IN NANOCRYSTALLITES X 1 Y 2SiO 5∶Eu

稀土掺杂的硅酸盐是应用广泛的发光和光学材料．通过低温下格位选择激发的光致发光和衰减曲线测量，详细研究了纳米微晶Ｘ１－Ｙ２ＳｉＯ５Ｅｕ中两种发光中心之间的能量传递，给出了不同浓度下两种发光中心的发光衰减曲线和寿命。

Photoluminescence spectra of nanocrystallites X 1 Y 2SiO 5∶Eu were recorded at 15K using site selective excitation by a dye laser. The results show that there is a pronounced energy transfer from site 2→1 and the transfer rates increases with increasing of Eu 3+ concentration. The fluorescent lifetimes of the two sites were also measured as a function of concentration. As expected, we found that the lifetimes of site 2 decreases with increasing concentration. Decay curve measurement of site 1 under exciting site 2 revealed the transfer process directly. The mechanism of the energy transfer is discussed.