Optical absorption and photoluminescence studies of Dy3+ doped alkaline earth bismuth borate glasses

Abstract

Dy3+ doped alkaline earth bismuth borate glasses were prepared by the conventional melt-quenching method. The prepared glasses were characterized by absorption, excitation, emission and decay curves. Judd–Ofelt parameters were obtained from the absorption spectra recorded at 400–2000nm. All the samples were excited at different wavelengths from UV (350 nm) to blue (450--470 nm) light and respective emission spectra are recorded. The intensity ratio of yellow to blue (Y/B) indicates that Dy3+ ions are present in low symmetry site. B2O3–Bi2O3RO (R = Ba, Sr & Ca) glasses emit efficient white light under different excitation wavelengths, which match well with the emission of commercial GaN-based blue LEDs and InGaN-based LEDs respectively. CIE coordinates were calculated from the emission spectra and found that they fall in white light region. Decay curves show single exponential nature up to 1mol% of Dy3+ concentrations and then turn into non-exponential for 2mol% of Dy3+ ions. Lifetime of these glasses decreases with increase of Dy3+ ion concentration.