Electronic structure and optical properties of europium-activated yttrium oxide phosphor

The electronic structure and optical properties of a red phosphor, ${\mathrm{Y}}_2$ ${\mathrm{O}}_3$:Eu, have been studied using the first-principles molecular-orbital and band-structure methods. Using the calculated one-electron energy levels, several properties of the host material and properties of the phosphor based on host-impurity interactions have been explained. However, it has been found that the luminescence properties of ${\mathrm{Eu}}^{3+}$ require the spin-orbit effects to be included in the computational methods.