Intense green emission from Tb3+ ions doped zinc lead alumino borate glasses for laser and w-LEDs applications

Abstract

Zinc Lead Alumino Borate (ZPAB) glasses doped with varying concentrations of Terbium (Tb3+) ions have been prepared via melt quenching technique. Structural studies like XRD and FT-IR were performed to ascertain the amorphous nature and functional groups present in the as prepared glasses respectively. Photoluminescence (PL) properties of the as prepared glasses were investigated by performing excitation and emission spectral studies under 545 nm and 369 nm wavelengths respectively. Under n-UV excitation, these glasses exhibit four emission peaks due to transitions from the excited 5D4 level of Tb3+ to 7FJ (J = 3 to 6) ground level. Among all, the intense emission band was observed at 545 nm corresponding to the 5D4→7F5 transition and the emission intensity increases up to 1 mol%, beyond concentration quenching took place. The Dexter theory confirms the possibility of energy transfer via electric dipole-dipole interaction between Tb3+-Tb3+ ions. The CIE chromaticity coordinates and color purity were evaluated which falls in intense green region and close to European Broadcasting Union illuminant green. The PL decay studies were carried out to know the experimental lifetimes of the fluorescent levels of Tb3+ ions. The lifetime measured for 5D4→7F5 transition of the as prepared glasses decreasing with increase in Tb3+ ions concentration, may be due to efficient energy transfer between Tb3+-Tb3+ ions. The aforementioned results confirm potentiality of these glasses in solid state green laser and as a green component in tricolor w-LEDs.