Phosphor in glass with Eu3+ and Pr3+-doped silicate glasses for LED color conversion

• Phosphor-in-glasses (PiGs) using rare earth ion doped silicate glasses were fabricated.
• Glasses doped with Eu2O3 and Pr2O3 improved CRI and CCT of white LEDs.
• PiGs with rare earth ions showed practical feasibility for LED application.
• Spectral interaction and the limitation of rare earth ions were discussed.

Phosphor-in-glasses (PiGs) with rare earth (RE) doped SiO2–B2O3–RO glasses were prepared by embedding YAG:Ce3+ as the yellow phosphor. Eu3+ and Pr3+ were used to dope the glass, varying their concentrations in order to provide red emissions for possible chromaticity-control of white-light emitting diodes (WLEDs). The glass-to-phosphor mixing ratio was also varied to find the proper combination for color-controlled white LEDs. PiGs with RE-doped glasses were sintered at 750 °C and polished to 250 μm in thickness for blue LED color conversion. The photoluminescence spectra of the PiGs were monitored after they were mounted on commercial blue LED chips. Variation of color coordination, color rendering index and correlated color temperature were observed due to red emissions from the doped RE-ions. The spectral contribution of Eu3+ and Pr3+ ions to white LEDs under 450 nm LED excitation was discussed. The spatial distribution of phosphors within the glass matrix, and their possible interaction, was inspected by SEM. The thermal quenching effect was also investigated.