Yb3+ concentration influences UV-Vis to NIR energy conversion in nanostructured Pr3+ and Yb3+ co-doped SiO2-Nb2O5 materials for photonics

We describe the synthesis of Pr3+/Yb3+ co-doped and Pr3+-doped SiO2-Nb2O5 nanocomposites; we also investigate energy transfer processes between the doping ions, which involve UV-Vis to infrared energy conversion. The emission spectra in the near infrared (NIR) region, 900-1650 nm, indicated energy transfer from Pr3+ to Yb3+ upon blue excitation of the Pr3+ ions. UV charge transfer band excitation elicited efficient Yb3+ emission at about 1.0 µm. The nanocomposite co-doped with 0.5 mol% Pr3+ and 1.0 mol% Yb3+ provided maximum energy transfer efficiency. The Pr3+ ion 3P0 excited state lifetime decreased from 11.8 to 3.7 µs as the Yb3+ ion content in the Yb3+/Pr3+ co-doped nanocomposites increased from 0.25 to 1.0 mol%. This observation attests for energy transfer from Pr3+ to Yb3+ ions. On the basis of these results, Pr3+/Yb3+ co-doped SiO2-Nb2O5 nanocomposites are promising materials for UV-Vis to NIR energy conversion.