掺Bi的MgO-CaO-Al_2O_3-SiO_2玻璃的吸收和近红外发光特性

研究了4种不同Bi_2O_3掺杂量(0.5%,1%,2%和3%,摩尔分数)的23MgO-11CaO-15Al_2O_3-51SiO_2(摩尔比)玻璃的发光特性。测量了吸收光谱、荧光光谱和荧光寿命。通过电子顺磁共振图谱观察了玻璃受γ辐射前后结构的变化,探讨了玻璃颜色变化和近红外发光的机理。结果表明:在500nm激发下,随着Bi_2O_3掺杂量从1%到3%的逐渐增加,发光波长发生红移,荧光半高宽从312nm增加到352 nm;最优的Bi_2O_3掺杂量为1%,玻璃的受激发射截面和荧光寿命的乘积为3.10×10~(-24)cm~2·s;γ辐射后发光强度的增加和玻璃颜色加深的现象说明Bi掺杂玻璃的近红外发光中心可能是低价态的Bi离子或者Bi团簇。

ABSORPTION AND NEAR INFRARED LUMINESCENCE PROPERTIES OF Bi-DOPED MgO-CaO-Al2O3-SiO2 GLASSES

The luminescence properties of 23MgO-11CaO-15Al2O3-51SiO2 glasses (mole ratio) doped with 0.5%,1.0%,2.0% and 3.0% (mole fraction,the same below) Bi2O3 were investigated.Absorption spectra,emission spectra and fluorescence lifetime of the glasses were measured.Electron paramagnetic resonance was used to study the structural change after gamma ray irradiation.The mechanisms of glass coloration and near infrared luminescence were discussed.The results show that under 500nm light excitation,the emission peak was red-shifted and fidl-width at half-maximum changed from 312 to 352 nm with increasing Bi2O3 from 1% to 3%.The optimal doping dosage of Bi2O3 in 23MgO-11CaO-15Al2O3-51SiO2 glass was 1%.The product of the stimulated emission cross section and the lifetime of this glass was 3.10×10-24 cm2·s.The increase of emission intensity and the darkening effect after gamma ray irradiation indicate that near infrared luminescence center of Bi-doped glasses should be contributed to low valence of Bi ions or Bi clusters.