Photoluminescence characteristics of red phosphor Eu 3+, Sm 3+ co-doped Y 2O 3 for white light emitting diodes

Abstract

Y 2O 3:Eu, Sm phosphors with red emission were prepared with various doping concentrations of Eu and Sm ions and firing temperatures ranging from 900 to 1400 °C by the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence analysis were used to characterize the phosphors. The crystallinity of the cubic phase of the synthesized sample increased with increasing firing temperature. The particle size of the red phosphor was observed to be about 0.5–1.0 μm. The co-doping with Eu and Sm ions broadened the excitation band of the Y 2O 3:Eu, Sm phosphors and enhanced their emission intensity under 390 and 405 nm light excitation. The weak f–f transition in the range from 350 to 420 nm, due to the ‘ 5H 5/2– 4D 1/2’ and ‘ 5H 5/2– 4K 11/2’ transitions of the Sm ions, has a broad excitation spectra and increased emission intensity.