Photoluminescent properties and Judd–Ofelt analysis of novel Na0.5Sr0.25NbO3: Eu3+ red phosphor with high quantum efficiency

Abstract

We report on a novel Na0.5Sr0.25NbO3: Eu3+ phosphor fabricated by a molten salt synthesis method with the potential application in white light-emitting diodes (WLEDs) as a red phosphor. The crystal structure, morphology, emission/excitation spectra, as well as decay curves were characterized with X-ray diffraction, Scanning Electron Microscope and photoluminescence spectrometer, respectively. Concentration quenching occurred when the concentration of Eu3+ was beyond 5 mol% due to the dipole-dipole interaction by nonradiative energy transfer. Besides, the effect of the crystal field surrounding the Eu3+ ions on the luminescent performance under 396 nm and 466 nm excitions has been investigated by the Judd–Ofelt theory. The result indicated that the quantum efficiency of the phosphor was 62.65% excited by 466 nm, which was superior to 41.43% excited by 396 nm. The optimal sample’s CIE coordinates were (0.6471, 0.3504) with the color purity of 97%, showing a potential application in (WLEDs) illumination field.