Spectroscopic studies of Pr3+ doped lithium lead alumino borate glasses for visible reddish orange luminescent device applications

Abstract

Abstract Lithium Lead Alumino Borate (LiPbAlB) glasses doped with Pr 3+ ions were prepared via melt quenching technique to study their luminescence behavior using absorption, excitation, photoluminescence (PL) and decay spectral studies. A broad hump observed in XRD confirms the amorphous nature of the as-prepared glass. The glass transition temperature (T g ) and thermal stability (ΔT) were measured from Differential Scanning Calorimetry (DSC). FT-IR and Raman studies were performed to understand the network functional groups involved in the host glass. Various radiative parameters for the prominent fluorescent levels of Pr 3+ were evaluated with in the frame work of Judd-Ofelt theory. PL and confocal images recorded under 445 nm Continuous Wave (CW) diode laser excitation were used to understand the visible emission characteristic features of the as-prepared glasses. The decay profiles of 1 D 2 → 3 H 4 show single exponential for lower concentration and non-exponential for higher concentration resulting decrease in experimental lifetime (τ exp ) with increase in concentration. Such decrease in τ exp and decay conversion from single to non-exponential with increase in rare earth ion concentration has been attributed to the cross-relaxation processes and subsequent concentration quenching observed. From the emission cross-sections, branching ratios, quantum efficiency, CIE coordinates and confocal images, it was concluded that 1 mol % Pr 3+ ion concentration is optimum in LiPbAlB glasses to develop visible reddish orange luminescent devices.