Charge transfer and europium trapped exciton states in Eu3+/Eu2+ doped phosphors

Abstract

Effects of temperature on the luminescence of LiMgPO₄ and β-Ca₂SiO₄ doped with Eu³⁺ and Eu²⁺ is presented. The short distance compensation of the Eu³⁺ in the Ca₂+ sites in β-Ca₂SiO₄:Eu²⁺/Eu³⁺ and the long distance compensation of Eu³⁺ in the Mg²⁺ or other sites in LiMgPO₄:Eu²⁺/Eu³⁺ is responsible for different temperature behaviour of the luminescence in both materials. The importance of the energy of the Fermi level is also discusses.