Blue-yellow multicolor phosphor, Eu²⁺-activated Li₃NaSiO₄: Excellent thermal stability and quenching mechanism

A multicolor emission phosphor can become a new luminescent material for emitting devices such as LEDs. However, most multicolor emission phosphors require two or more luminescent ions, such as Eu²⁺/Mn²⁺ and Eu²⁺/Tb³⁺/Mn²⁺. In this study, novel multicolor phosphor materials Li₃NaSiO₄:Eu²⁺ were successfully synthesized using a conventional solid-state reaction. The phosphors showed a unique white color with multicolored blue and yellow emissions under a near-ultraviolet light at 360 nm. Based on this result, there seems to be strong evidence that Eu²⁺ ions are substituted for two cation sites, NaO₆ and LiO₅. Moreover, Eu²⁺-doped Li₃NaSiO₄ phosphors exhibit excellent thermal stability in comparison with Eu²⁺-activated silicate phosphors owing to the presence of electron traps, which can be activated at high temperatures.