Influence of Mg doping on structure and optical properties of red-emitting phosphor Li2TiO3:Mn4+

Li₂TiO₃:Mn⁴⁺ has been previously identified as a potential candidate to replace commercial red-emitting Eu²⁺-activated phosphors. Its luminescent efficiency is limited by the presence of defects and the sensitivity of Mn⁴⁺ to redox processes. A series of co-doped Li₂TiO₃: x Mg²⁺, 0.01 Mn⁴⁺ samples were prepared to gain insight on the effect of electron doping on the structure and photoluminescent properties, through characterization by powder X-ray diffraction, elemental analysis, and optical spectroscopy. As Mg²⁺ substitutes for Li⁺, the ordered arrangement of cations within the honeycomb layers in the parent structure (Li₂SnO₃-type, an ordered derivative of rocksalt) gradually transforms to a more disordered arrangement. The increased cation site disorder leads to less intense and broader emission peaks as well as lower quantum yields.