Growth arid properties of long-lasting phosphors stored with solar energy

Eu^<2+:>Ba_2SiO_4和Eu^<2+:>\Bs_3SiO_5晶体在紫外或可见光激发下分别产生峰值波长为510 nm和590 nm的宽带发光。测量了持久磷光强度随温度和时间的变化。除了Eu^<2+>的荧光寿命为10^6秒外，辐射衰减时间分布在1 ~ 10^3秒的宽范围内。在100 ~ 500 K温度范围内，1秒以上的衰减曲线拟合t^n（n ~ 1）。长时间磷光强度的温度依赖性集成，在一个时间域。服从修正的阿伦尼乌斯方程。热活化能包括辐射和非辐射衰变过程。这些结果表明，由紫外或可见光激发产生的电子和空穴通过热跳和/或隧穿回到晶体中的Eu2+位点，并在Eu^<2+>处进行辐射重组。

UV or visible excitation for Eu^<2+:>Ba_2SiO_4 and Eu^<2+:>\Bs_3SiO_5 crystals produces broadband luminescence with peak wavelengths of 510 and 590 nm, respectively. The intensities of the long-lasting phosphorescence were measured as functions of temperature and time. The radiative decay times are distributed in the wide range of 1-10^3 seconds besides the Eu^<2+> fluorescence lifetime of 10^6 seconds. The decay curves above one second in the temperature range of 100-500 K fit t^n(n〜1). The temperature dependence of the long-lasting phosphorescene intensities integrated, in a time domain. obeys the modified Arrhenius's equation. with thermal activation energies including radiative and nonradiative decay processes. These results suggest that electrons and holes produced by UV or visible excitation move back to Eu2+ sites in the crystals through thermal hopping and/or tunneling and recombine radiatively at Eu^<2+>.