Narrow-band Red-emitting Phosphor, Gd3Zn2Nb3O14:Eu3+ with High Color Purity for Phosphor-converted White Light Emitting Diodes

Abstract

In this work, we synthesized and characterized a narrow band red emitting Gd3Zn2Nb3O14:Eu3þ phosphor in order to improve the color qualities of warm white light emitting diodes. The phosphors were synthesized via conventional solid state reaction method and investigated the evolution of emission spectra with partial occupation of Zn2þ ions on both A and B site of the fergusonite type structure. The structural and luminescence property analysis corroborates the occupancy of Eu3þ ions in the Gd3þ/Zn2þ ion site (A site). The developed phosphor exhibits a strong red emission peaking at 613 nm with a fwhm of merely ~3.50 nm under the 392 nm excitation. These compounds produce narrow emissions in the visible red spectral regions that are highly professed by human eye and lead to outstanding chromatic saturation of the red spectra. The enhanced electric dipole transition intensity arises from the symmetry distortion of Eu3þ ions caused by the introduction of Zn2þ ions in the lattice. The distortion of the A site symmetry and the red shift of the charge transfer energy leads to an intense 5D0 e 7F2 hypersensitive electric dipole transition under 392 nm excitation. The relative emission intensity was found to be maximum at x ¼ 0.40 and is 3.9 times higher than that of the commercial red phosphor under the 392 nm excitation. These phosphors with remarkable CIE chromaticity coordinates (0.64, 0.35), good CCT values along with high color purity (94.2%) might have significant applications in display devices and evidence as an efficient red phosphor.