Light-extraction enhancement of white LEDs with different phases of TiO2:0.01Eu3+ spheres

We report the synthesis of TiO2:0.01Eu3+ spheres by a solvothermal reaction method and their utilization in the enhancement of light-extraction efficiency. The light-extraction efficiency was enhanced by increasing the extraction probability of the internal and external reflected photons in the YAG:Ce3+ yellow phosphor based white light-emitting diodes (WLEDs). The crystalline structure of TiO2:0.01Eu3+ spheres was investigated by an X-ray diffraction analysis. The anatase phased TiO2:0.01Eu3+ spheres exhibited a typical red emission under 463.5 nm wavelength. The diffused reflectance spectra displayed higher reflectance for rutile phase and lower for anatase phase. However, compared to the typically, combination of YAG:Ce3+ yellow phosphor and blue LED chip, fabricated WLED, the light-extraction efficiency of WLED was improved to 80% when TiO2: 0.01Eu3+ spheres were mixed with YAG:Ce3+ phosphor in the fabrication process.