Electronic and Optical Properties of Luminescent Centers in Halides and Oxides

Luminescent materials, such as phosphors and scintillators, are widely used for fluorescent lighting, laser, medical imaging, nuclear material detection, etc. . The luminescence is usually activated by impurities (or activators), which act as luminescence centers. The activators are typically multi-valent ions that insert multiple electronic states in the band gap of the host material. In this talk, first-principles calculations of electronic structure and optical transitions are shown for a wide range of activators, including rare-earth ions (e.g., Ce$^{\mathrm{3+}}$, Eu$^{\mathrm{2+}})$, ns$^{\mathrm{2}}$ ions (the ions that have outer electronic configurations of ns$^{\mathrm{2}}$, such as Tl$^{\mathrm{+}}$, Pb$^{\mathrm{2+}}$, Bi$^{\mathrm{3+}})$, and transition-metal ions (e.g., Mn$^{\mathrm{4+}})$, in a large number of halides and oxides. The results reveal how the activator-ligand hybridization affects the emission energy and the luminescence mechanism. New phosphors and scintillators are proposed based on the chemical trends emerging from the calculations of a large number of materials.