Site distortion in Li₂SrSiO₄: Influence on Pr³⁺ emission and application in wLED

Luminescence of Pr³⁺ in Li₂SrSiO₄ showed a broader f–f emission band compared with YAG:Pr³⁺. Atom parameters of Li₂SrSiO₄ crystal were refined to provide data for quantifying the distortion of [SrO8] polyhedron. The distortion of [SrO8] was compared with that of [YO8] polyhedron in YAG to show the different Pr³⁺ environments in Li₂SrSiO₄ and YAG. Then, Pr³⁺ was co-doped with Eu²⁺ in Li₂SrSiO₄ to provide a single phosphor for wLEDs. Energy transfer processes from 5d of Eu²⁺ to both ³P₂ and ¹D₂ of Pr³⁺ were observed. The interaction type between Eu²⁺–Pr³⁺ was proved to be dipole-quadrupole and kinetics of the energy transfer process was discussed based on Inokuti–Hirayama model.