Tunable photoluminescence and energy transfer of YBO sub(3):Tb super(3+), Eu super(3+) for white light emitting diodes

Rare-earth (Eu super(3+), Tb super(3+)) ion co-doped YBO sub(3) phosphors with a morphology of uniform flower-like assembly are fabricated by a facile hydrothermal method without the use of surfactant, organic ligands, or further sintering treatment. Photoluminescence (PL) studies have demonstrated that under the excitation of 365 nm ultraviolet (UV) light, YBO sub(3):Tb super(3+), Eu super(3+) emits a white light, including three emissions: a blue band attributed to self-trapped excitons (STEs), a green band due to the Tb super(3+) transition of super(5)D sub(4)- super(7)F sub()j( j= 6, 5, 4, and 3), and a red band due to the Eu super(3+) transition of super(5)D sub(0)- super(7)F sub()j( j= 0, 1, 2, 3, and 4). Energy transfers from host YBO sub(3) to Tb super(3+), and Eu super(3+) and Tb super(3+) to Eu super(3+), as well as tunable emission by varying the relative doping ratios are demonstrated. The combination of blue emission from STEs with green and red emissions from activators provides a novel and efficient technique to make white light emitting diodes (WLEDs).