A Novel Orange-Red Emitting ZnB4O7:Eu3+Phosphor with Urchin-Like Nanostructure

A novel phosphor, ZnB 4 O 7 :Eu 3+ , with urchin-like structure consisting of radially arranged high density nanorods was successfully synthesized by hydrothermal process at 150°C for 24 h. The nanorods were measured from 200 to 400 nm in diameter and several µ m in length. The urchins were few µ m to 40 µ m in diameter. The ZnB 4 O 7 :Eu 3+ phosphors were efficiently excited by ultraviolet (UV ~ 254 nm) to visible light of ~ 220 to 450 nm and exhibited intense orange-red emission consisting of main peaks at 590, 615, and 695 nm due to the charge transfer in the host andf→ftransitions ( 5 D 0 to 7 F 1,2,4 ) of the Eu 3+ ions. Effect of the Eu 3+ ions concentration on the photoluminescence (PL) emission intensity was investigated and it was found that 5 at% Eu 3+ is the optimum concentration. Meanwhile, the concentration quenching mechanism was discussed. The key parameters, such as temperature dependent PL and CIE values of ZnB 4 O 7 :Eu 3+ phosphors, were studied. The ZnB 4 O 7 :Eu 3+ phosphor exhibited good thermal stability and better absorption cross section compared to the commercial Y 2 O 2 S:Eu 3+ phosphor. All these characteristics indicate that the phosphor will be a potential candidate for the UV based white LEDs.