Synthesis and Photoluminescence Properties of the Novel Red Phosphor Gd2MoB2O9: Eu

A novel phosphor, Gd₂MoB₂O₉:Eu³⁺ has been synthesized by solid-state reaction and its photoluminescence in UV-VUV range are investigated. A sharp excitation band is observed in the region of 120–135 nm, which is related to the charge-transfer (CT) band of Gd³⁺. The broad band around 135–160 nm can be assigned to the BO₃ host absorption. The broad bands around 248 nm are assigned to the CT band of Eu³⁺-O2-. The phosphors emit strong red luminescence centered at about 591 nm, 614 nm and 626 nm due to the⁵D₀–⁷F₁ and ⁵D₀–⁷F₂ transitions of Eu³⁺. The main emission peak under 254 and 147 nm excitations also shows different shifts with increasing Eu³⁺ concentration. This could be due to the different luminescence sites selected at high doping concentrations of Eu³⁺. Gd₂MoB₂O₉:Eu³⁺ shows the pure red emission under both 254 and 147 nm excitations.