Effect of cerium oxide and niobium oxide addition on absorption and emission properties of bismuth doped silicate glasses

• Various valence state changes of bismuth are acquired and analyzed.
• Near-IR emission originates from low valence Bi ions.
• The broadband NIR emission can be ascribed to the Bi+:3P1 → 3P0 and Bi0:2D3/2 → 4S3/2.

Ce/Bi and contrastive Nb/Bi co-doped silicate glasses were prepared to investigate the effects of CeO2 and Nb2O5 on the absorption and emission properties. Based on the spectrum measurement, interestingly it was found that the changes about valance state of Bi ions in SACB–xCeO2 and SCB–yNb2O5 are different. Furthermore, near-infrared (NIR) emission intensity all decreased with the addition of oxidizing agents. It may provide an evidence for the low valance state bismuth (Bi+, Bi0) ions being the broadband NIR active center. According to the spectral changes, we also discussed the existence form of Ce ions and Nb ions in the chemical environment around NIR active center and the possible energy level transformations of NIR emission.