Reidinger defects induced thermally stable green emission from Eu2+, Mn2+ co-doped Ba0.75Al11O17.25 transparent ceramics

In this paper, Ba0.75Al11O17.25 was selected as the host for the Eu2+ and Mn2+ co-dopants due to the Reidinger defects in its lattice. Upon the 365 nm excitation, the phosphors presented the cyan to green tunable emission by changing the doping concentration of Mn2+. Moreover, this phosphor possesses zero-thermal quenching up to 448 K due to the interaction between the traps and Eu2+/Mn2+. The completely densified ceramic guaranteed the high optical transmittance (∼72 % at 516 nm) and thermal conductivity (4.3 W·m−1·K−1 at room temperature). When combined with a 6 W commercial 365 nm emitting LED chip, the temperature of the ceramic eventually stabilized at 428 K and the luminous efficacy of the LED device was almost not influenced by the thermal quenching effect. This work may open a way for exploring new phosphor conversion materials for HP/HB PC solid state lighting.