Blue-yellow emission adjustability with aluminium incorporation for cool to warm white light generation in dysprosium doped borate glasses

Abstract

A series of white light emitting Dy3+ doped lead borate (DY) and lead alumino borate (DYA) glasses have been prepared by melt quench technique and are explored by XRD, FTIR, optical absorptions, fluorescence and density measurements. In this paper an effort has been made to compare the structural changes and luminescence efficiencies of prepared glasses by changing dysprosium oxide content and glass network environment by adding aluminium oxide. The XRD profile of all the glasses confirms their amorphous nature and FTIR study shows the presence of BO3 and BO4 groups. Incorporation of Al2O3 in the glass system is responsible for a strong effect on luminescence of the present glass system. There is a strong correlation between Dy3+ ions concentration and the host glass composition on the energy transfer mechanism. The decay curves deviate gradually from single exponential function at lower concentrations to non-exponential behavior at higher concentrations. The Inokutie Hirayama (IH) model for S= 6 fits well the non-exponential decay curves that indicate dipole-dipole type energy transfer between donor and acceptor ions. The calculated chromaticity coordinates lie in the white region of CIE 1931 chromaticity diagram and are in excellent proximity with the standard equal energy white illuminant (0.333, 0.333). Furthermore, the calculated correlated color temperature and the yellow to blue (Y/B) ratio of the synthesized photonic glasses may offer the possibility of tuning the white light by varying concentration and host environment which could be useful for various photonic based device applications.