Synthesis and luminescent properties of novel Ba2−xEuxZr2−yHfySi3O12 phosphor

A series of Eu2+ activated luminescent materials according to the composition of Ba2−xEuxZr2−yHfySi3O12 were synthesized using a high temperature solid-state reaction method starting from metal oxides and carbonates. Single phase powders were obtained using two annealing steps and boric acid as a flux. Firstly, starting materials were sintered at 1450 °C for 5 h under CO atmosphere and subsequently annealed at 1200 °C for 5 h under N2/H2 (95%/5%) gas flow. All samples were characterized by powder X-ray diffraction (XRD) analysis, thermal quenching (TQ), fluorescence lifetime measurements and photoluminescence (PL) techniques. Moreover, emission colour points, luminous efficacies and quantum efficiencies (QE) were calculated and discussed as a function of Eu2+ concentration and Zr/Hf ratio of the host lattice.

► Novel efficient cyan emitting phosphor.
► Increased Hf4+ content shifts Eu2+ emission maximum towards blue.
► Fluorescence decay time of Eu2+ decreases with higher Hf4+ content.
► Phosphors show less than 50% thermal quenching up to 200 °C.