Novel red-emitting Sr2LaSbO6:Eu3+ phosphor with enhanced 5D0→7F4 transition for warm white light-emitting diodes

Eu3+-activated double perovskite Sr2LaSbO6 phosphors with two red-emitting bands centered at 610 and 707 nm have been synthesized by the conventional solid-state reaction method. The phase purity and luminescent properties of the fabricated samples were characterized by X-ray diffraction (XRD), photoluminescence excitation (PLE) and emission (PL) spectra, decay curves as well as temperature dependent PL. The XRD results certified that all the samples demonstrated a pure cubic phase. Under the excitation of 465 nm, the phosphors show a deep red-emitting with chromaticity coordinates (0.634, 0354) due to the emission at 707 nm from D-5(0)-> F-7(4) transition of Eu3+ ion. The PL emission intensity of the sample increased by the increment of Eu3+ ion concentration until the concentration quenching occurred when x = 20 mol%. Additionally, the obtained Sr2LaSbO6:Eu3+ phosphor exhibited good thermal stability with the PL intensity of Eu3+ at 423 K maintains 71.2% of that at room temperature. Furthermore, the fabricated LED device using a 465 nm blue-InGaN chip combined with a blend of commercial yellow phosphor Y3Al5O12:Ce3+ and red-emitting phosphor Sr2LaSbO6:Eu3+ can get a white light possessing a low CCT (5260 K) and a high CRI (763). (C) 2017 Elsevier Ltd. All rights reserved.