Photoluminescence properties of Tb3Al5O12:Ce3+, Mn2+ phosphor ceramics for high color rendering index warm white LEDs

Tb3Al5O12:Ce3+, Mn2+ (TAG:Ce3+, Mn2+) phosphor ceramics with different doping of Mn2+-Si4+ ions pair were fabricated by the high temperature solid state reaction in a flowing oxygen atmosphere. The emission colors could be changed from yellow-green to orange-red through controlling the doping concentration of Mn2+-Si4+ ions in the TAG:Ce3+, Mn2+ phosphor ceramics. The red emission from the phosphor ceramics mainly came from the 4T1→6A1 transition of Mn2+ ions via the Ce3+→Mn2+ energy transfer under the 460 nm excitation. With the increase of Mn2+ doping concentration, the emission peak of the emission spectrum could reach 605 nm. By combining the optimized phosphor ceramic with the 460 nm commercial blue light emitting diode (LED) chip, the white light with low correlated color temperature (CCT) of 3426 K and high color rendering index (CRI) of 84.4 was obtained, indicating the good potential of TAG:Ce3+, Mn2+ phosphor ceramics for warm white LED applications.