Narrow-linewidth red-emission Eu³⁺-doped TiO₂ spheres for light-emitting diodes

In this work, the amorphous Eu³⁺-doped TiO₂ spheres were synthesized by low cost mixed-solvent method, while the anatase and rutile spheres can be obtained by annealing the as-synthesized amorphous TiO₂ spheres at elevated temperatures. The optical properties of Eu³⁺-doped TiO₂ spheres were also investigated, and strong red emission (centered at 610 nm) with narrow line-width of 30 nm was observed under 465 nm or 394 nm excitations for the Eu³⁺-doped anatase TiO₂ spheres. Our findings indicate the potential of using Eu³⁺-doped TiO₂ spheres to achieve red emission with InGaN blue light emitting diodes (LEDs). Owing to the high light extraction efficiency in the GaN-based LEDs using anatase TiO₂ spheres as demonstrated in our previous works, this work shows the strong potential of Eu³⁺-doped TiO₂ spheres as the red phosphor material for high efficiency GaN-based white light-emitting diode.