Structural characterization and photoluminescence properties of B2O3–Bi2O3–SiO2 glass containing Dy3+ ions

Abstract

Bismuth borosilicate (BBS) glasses have been widely applied in laser, LED device and nonlinear optics. This work investigates the structural evolution of BBS glasses using the spectral transformation of Dy3+ ions as probe. Glass systems of composition xB2O3-(60-x) Bi2O3–40SiO2-1Dy2O3(x = 10, 20, 30, 40) (mol%) were prepared by the conventional melt quenching technique. The diffraction band of XRD pattern peaked at 2θ = 28.50° slightly shifts to smaller angle with the amount of B2O3 resulting from the more compact network. The absorption cut-off edge in ultraviolet region shifts to the shorter wavelength and band gap energy is enhanced, indicating that the increasing B–O- bonds with the stronger covalence than Bi–O bond. According to Fourier transform infrared (FTIR) and Raman spectra, the conversion of [BiO3] tetrahedral into [BiO6] octahedral takes place. Interestingly, [BO4] tetrahedral began to be transformed into [BO3] triangle when the content of B2O3 exceeds 30mol%, suggesting that the phenomenon of "boron abnormality" exists in BBS glass. The increase in Ω2 values and Y/B ratios reveals the intensifying disorder of glass network. The fluorescence intensity, decay lifetime (τexp) and quantum efficiency (η%) increase due to the enhancement of multi-phonon relaxation process of 4I13/2, 4G11/2 and 4I15/2 level populating 4F9/2 level.