Down-shifting photoluminescent properties of Tb3+ doped phosphate glasses for intense green-emitting devices applications

Abstract

Tb3+ doped BZLP glasses were prepared via a melt-quenching route and investigated thoroughly using spectroscopic techniques such as XRD, UV-VIS absorption and photoluminescence (PL) to explore their utility in visible photonic device applications. The information pertaining to glass transition temperature, melting temperature, and thermal stability were understood by using recording the differential scanning calorimetry (DSC) spectrum for an undoped BZLP glass. The total weight loss during the glass composition melting process was analyzed using Thermogravimetric curves. The UV spectral information recorded for the titled glasses reveals the optical bandgap falling in the range from 4.57 to 4.19 eV. The prepared Tb3+ doped BZLP glasses exhibit intense green emission along with relatively less intense blue, yellow, and red peaks under 373 nm excitation. In the resultant PL spectra, the emission intensity increases with the activator concentration of Tb3+ ions from 0.5 to 5.0 mol%. The estimated CIE chromaticity coordinates falling in the green region reveal the aptness of the titled glasses as a green constituent in visible photonic devices. The PL decay curves show the bi-exponential behavior with an average decay time of 2–3 ms. The temperature-dependent PL profile shows fewer changes in spectra and has a relatively high activation energy value, confirming the high thermal stability. Various results obtained for Tb3+ doped BZLP glasses finally reveal their usage as a green emitter needed to fabricate w-LEDs and other green-emitting photonic device applications.