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.