Bi^(3+)和Eu^(3+)在Ca_2SiO_4中的发光和能量传递

LUMINESCENCE AND ENERGY TRANSFER OF Bi3 + , Eu3+IONS IN Ca2SiO4 HOST

用高温固态反应合成了Ca_2SiO_4:Bi^(3+),Ca_2SiO_4:Eu^(3+)和Ca_2SiO_4:Eu^(3+),Bi^(3+)发光体。讨论了不同掺杂量和掺杂种类时Bi^(3+)对Eu^(3+)的~5D_0-~7F_1,~5D_0-~7F_2发射的影响规律。实验发现,Ca_2SiO_4:Bi^(3+)在紫外线激发下发出明亮的蓝色光,Ca_2SiO_4:Eu^(3+),Bi^(3+)中的Bi^(3+)能将激发能传递给Eu^(3+),使Eu^(3+)的~5D_0-~7F_1和~5D_0-~7F_2两种跃迁都大大加强,同时,Bi^(3+)也发出鲜艳的紫色光。

The luminophors of Bi3+-doped and Bi3 + , Eu3+-co-doped Ca2SiO4 were sythesised. The crystalline phase was checked by X-ray powder diffraction. By contrast, the d values of crystallogram are in agreement with that of ASTM file No.9-351. Therefore the products were determined to be mono-clinic 3-Ba2SiO4. The excitation and emission spectra were measured by RF -510 fluorospectrometer.The luminescent properties of Ca2SiO4:Bi3+ and Ca2SiO4:Eu3+, Bi3+ were investigated.We have found that Ca2SiO4:Bi3+ shows bright indigo-blue luminescence with max about 410nm under UV excitation. There are two bands in its excitation spectra, max = 314nm and max = 352nm respectively. When Bi3+ concentration increases, the excitation band of 314nm decreases rapidly and that of 352nm increases fast, and the ratio of the two band areas shows a linear relationship. The optimum concentration of Bi3+ ion for Ca2SiO4 is 0.02mol corresponding to 352nm excitation.The excitation spectra of Eus+ emission for Ca2SiO4:Eu3+, Bi3 + appear a powerful broad band of Bi3+ with maximum value of 355nm besides excitation lines of Eu3+. Under excitations of 340nm, 355nm and 365nm UV radiation, the emission of Eu3 + (6D0-7F1, 5D0-7F2 transition) for Ca2SiO4 :Eu3+, Bi3+ is increased more greatly than that of Ca2SiO4 :Eu3+ . Moreover, there is an intensive emission of Bi3+ with the maximum value of 390nm.Using 340nm UV radiation as excitation, Ca2SiO4:Eu3+, Bi3+ shows intensive emissions of Eu3+ corresponding ton 5D0-7F1 and 5D0-7F2 transitions, but Ca2SiO4 :Eu3+ shows little emission under the same conditions. Results of these experiments show that there are energy transfer from Bi3 + ions to Eu3+ ions.Because the band overlapping of the emission band of Bi3 + with excita-tion lines of Eu3+ is in good condition, evidently, energy transfer from Bi3+ ions to Eu3 + ions is the cause of luminescence of Eu3+ sensitized by