Local structure regulating effect for the near infrared luminescence of Bi in zinic silicate and germanate glasses

Bi-doped zinic silicate glasses (SG) and germanate glasses (GG) were prepared and the relationship between Bi near infrared (NIR) luminescence and the glass structures were investigated. The absorption, visible luminescence, and X-ray photoelectron spectroscopy (XPS) spectra revealed that the lower valence state of Bi ions containing NIR active centers increased with the decrease of optical basicity in the two sets of glasses. However, the NIR emission in these glasses cannot be merely explained by the theory of optical basicity. In the SG glasses, there is no obvious structural change, the NIR luminescence can be well interpreted by theory of optical basicity. But there is a distinct transformation in the GG glasses, the abnormal fluorescence phenomenon can be connected with the local structure regulating effect. The mechanisms of the NIR emission and local structure regulating effect were discussed.