Luminous characteristics and 89Y-static NMR in red phosphor, Eu-doped Y2O3

Luminous properties of a red phosphor, Eu-Y2O3 (Eu-doped Y2O3) have been studied by Y-89 (nuclear spin 1/2)static NMR. Pure Y2O3 showed an anisotropic pattern with the peak centered at 299 ppm assigned to the Y atom in the site, where none of the 12 nearest neighbouring Y atoms are substituted by an Eu atom. The signal became broader with increasing doped Eu content. Additionally, a shoulder peak assigned to the Y atom in the site where one of the 12 nearest neighbouring Y atoms was replaced by one Eu atom appeared around 100-110 ppm in the samples with more than 1 mol/% Eu content. The spin-spin relaxation of the centered signal was mainly dominated by the dipole-dipole interaction mechanism between the Y-89 nucleus and the paramagnetic electrons of Eu3+ with 4f(6) electron configuration which substituted at. the second nearest and further neighbouring Y. In conclusion, the line-broadening of Y-89 Signal at constant Eu content was correlated with the Eu distribution on the basis of the facts that the phosphor sample with higher brightness showed broader linewidth and the intensity of the ESR signal corresponding to the lattice defects has no relation to the brightness.