Upconversion luminescence in Er³⁺/Yb³⁺ codoped PbO-Bi₂O₃-AI₂O₃-B₂O₃ glasses

Abstract

Er3+/Yb3+ co-doped glasses with the composition PbO-Bi2O3-Al2O3-B2O3 were prepared by melt quenching method. Optical absorption (OA) and photoluminescence (PL) and FT-IR spectra of all the glasses were recorded at room temperature. Green and red upconversion emissions centered at 525, 545 and 654 nm corresponding to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions have been obtained under the excitation of 980 nm laser at room temperature. From emission spectra it was observed that the intensity of red emission increases with increasing the concentration of Er3+ ions upto 0.8 mol% and decreases with the further increase in the concentration of Er3+ ions. The spectra have been analyzed in the light of structural modifications in the vicinity of the dopant rare earth ions, due to relative variations in the concentration of Al2O3 and B2O3 in the glass network.