Photoluminescence investigations on Sm3+ ions doped borate glasses for tricolor w-LEDs and lasers

Abstract

This work describes mainly the optical absorption, photoluminescence (PL) and decay spectral properties of Sm3+ ions doped borate glasses to understand their possible usage in tricolor w-LEDs and lasers.The XRD spectrum recorded for an un-doped glass confirms glassy nature of the as prepared glass. The Judd-Ofelt (J-O) intensity parameters evaluated from experimental oscillator strengths were used in estimating the various radiative parameters. Under 402 nm excitation, the PL spectra exhibit intense emission at 600 nm for which the decay spectral profiles were recorded.The decay profiles are converting from single exponential to non-exponential with increase in Sm3+ ion concentration ensuing decrease in experimental lifetimes which may be attributed to the efficient energy transfer through cross-relaxation process. The non-exponential decay curves fitted to I-H model reveals the interaction between the Sm3+ ions as dipole-dipole in nature. From the evaluated emission cross-sections, quantum efficiency, branching ratios and CIE co-ordinates, it is concluded that 1 mol% Sm3+ ions in these glasses are aptly suitable to fabricate reddish-orange luminescent devices.