EPR, FTIR, optical absorption and photoluminescence studies of Fe2O3 and CeO2 doped ZnO–Bi2O3–B2O3 glasses

Glasses containing heavy metal oxide of the composition (wt.%) 23B2O3–5ZnO–72Bi2O3–xFe2O3/CeO2 (0 ≤ x ≤ 0.0058 at.% in excess) were prepared by melt quenching technique. The glass formation was confirmed by XRD. FTIR spectra exhibit characteristic absorption bands for B2O3 and Bi2O3 for their various structural units. The EPR spectra exhibit two resonance signals at g ≈ 6.4 and g ≈ 4.2 for Fe2O3 doped glasses. The resonance signals at g ≈ 4.2 and g ≈ 6.4 are attributed to Fe3+ ions in rhombic and axial symmetry sites, respectively. The number of spins participating in resonance (N) and its paramagnetic susceptibility (χ) with composition has been evaluated. The effect of CeO2 and Fe2O3 on optical and structural properties of zinc bismuth borate glass was investigated. From EPR and optical studies it is observed that iron ions are present in trivalent state with distorted octahedral symmetry. The cerium is present in Ce4+ state. Upon 400 nm excitation the emission at 548 and 652 nm are attributed to the Bi2+ species. The emission at 804 nm upon 530 nm excitation suggests that Bi+ ions are present in the sample. It is interesting to observe that the optical band gap energy (Eopt) decreases with the increase of transition metal and rare-earth ion doping.