Luminescent characteristics of green emitting Li ₂Ca ₂Si ₂O ₇:Eu ²⁺ phosphor

We present a novel green emitting phosphor of Eu ²⁺-doped Li ₂Ca ₂Si ₂O ₇ which can be excited by ultra-violet light. The phosphors were synthesized at the low temperature of 900°C without any impurity phases by a solid-state reaction. The phosphor shows broad green emission centered at 520 nm under excitation at 350 nm. We found in the phosphor that the critical quenching concentration of Eu ²⁺ and the critical distance of energy transfer between Eu ²⁺ ions are 0.5 mol% and 56.2 Å, respectively. The thermal activation energy of the green luminescence was also measured to be 0.51 eV. The present work suggests that the Li ₂Ca ₂Si ₂O ₇:Eu ²⁺ phosphor is a kind of potential green-emitting phosphor.