Visible and near-infrared emission from Gd2O3:Sm3+ phosphor

Abstract

The optical properties of visible and NIR-emitting Gd2O3:Sm3+ (2, 4, 6, 8 and 10 mol%) materials were investigated via absorption, emission spectra and luminescence decay curves. Based on the emission spectra and Judd-Ofelt (JO) theory calculations, the JO intensity parameters (Ωλ, λ = 2, 4 and 6) were determined in order to probe the radiative behaviour of various Sm3+ excited energy levels. In addition, the stimulated emission cross-sections (σ(λp)) of the 4G5/2 → 6H5/2,7/2,9/2,11/2 and 4G5/2 → 6F3/2,5/2,7/2,9/2 transitions were determined. The radiative decay times (τR) calculated from JO theory and the measured lifetimes (τexp) obtained from the experimental decay curves for the 4G5/2 emitting level were employed to estimate the quantum efficiency (η) of Sm3+ ion, which were found to be 46, 47, 46, 46 and 46 %, for Gd2O3:Sm3+ (2, 4, 6, 8 and 10 mol%) samples, respectively. Accordingly, all these phosphors display medium quantum efficiency. The chromaticity coordinates were determined from the emission spectra, exhibiting orange-reddish colour emission for these materials. Nevertheless, the luminescence spectroscopy results indicated that these phosphors can be efficient candidates for visible and near-infrared optoelectronic devices.