Synthesis and Photoluminescence Properties of a Blue-Emitting La3Si8N11O4:Eu2+ Phosphor

Abstract

Eu²⁺-doped La₃Si₈N₁₁O₄ phosphors were synthesized by the high temperature solid-state method, and their photoluminescence properties were investigated in this work. La₃Si₈N₁₁O₄:Eu²⁺ exhibits a strong broad absorption band centered at 320 nm, spanning the spectral range of 300-600 nm due to 4f⁷ → 4f⁶5d¹ electronic transitions of Eu²⁺. The emission spectra show a broad and asymmetric band peaking at 481-513 nm depending on the Eu²⁺ concentration, and the emission color can be tuned in a broad range owing to the energy transfer between Eu²⁺ ions occupying two independent crystallographic sites. Compared to the Ce³⁺-doped La₃Si₈N₁₁O₄, the Eu²⁺-doped one shows a larger thermal quenching, predominantly owing to photoionization. Under 320 nm excitation, the internal and external quantum efficiencies are 44 and 33%, respectively.