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

摘要

Lithium Lead Alumino Borate (LiPbAlB) glasses doped with Pr3+ 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 (Delta T) 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 Pr3+ 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 D-1(2) -> H-3(4) show single exponential for lower concentration and non-exponential for higher concentration resulting decrease in experimental lifetime (tau(exp)) with increase in concentration. Such decrease in texp 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 % Pr3+ ion concentration is optimum in LiPbAlB glasses to develop visible reddish orange luminescent devices. (C) 2017 Elsevier B.V. All rights reserved.