Analysis of fluorescence characteristics of Sm3+-doped B2O3-rich glasses for Orange-light-emitting diodes

Abstract

Optical absorption and visible luminescence aspects including visible emission decay times have been examined for six Sm3+ (1 mol%)-doped B2O3-rich glasses comprising single and mixed alkali oxides which were synthesized via melting-and-quenching approach. Upon intense λexci. = 409 nm, fluorescence spectra displayed four bands peaked at 562 nm, 598 nm, 645 nm, and 706 nm owing to 4G5/2 upper level to 6H5/2, 6H7/2, 6H9/2, and 6H11/2 lower levels transitions respectively. Among identified emissions, orange fluorescence (598 nm) is found to be strong in all samples. Moreover Sm3+: Li ions having sample exhibits the dominant visible emissions band intensity in all samples, so for this sample, Judd–Ofelt (JO) analysis was carried out to calculate JO parameters Ωt (t = 2, 4, 6), and from them, radiative transition probabilities, branching ratios (calculated and experimental), and radiative lifetimes of Sm3+: 4G5/2 level to distinct lower energy states were derived utilizing absorption and emission spectra. CIE (Commission Internationale de l′éclairage) coordinates, correlated color temperature (CCT), color purity, color rendering index, and luminous efficiency of radiation were determined from visible luminescence spectra of all studied glasses, and obtained CIE coordinates and CCT values lie in the reddish-orange light region of CIE diagram, indicating their potential for orange LEDs (light-emitting diodes) application. Here derived CCT values are lower than the typical warm light sources CCT limit (<3200 K). 4G5/2 state luminescence decay patterns revealed double exponential behavior for assessing the measured lifetimes. Effective bandwidth, stimulated emission cross-section, and gain bandwidth were computed for observed luminescence transitions of Sm3+: Li ions possessing sample.