Temperature dependent red luminescence from a distorted Mn4+ site in CaAl4O7:Mn4+

Thermal luminescence quenching behavior of a phosphor is essential for application in phosphor converted white light emitting diodes (pc-WLEDs) because the phosphor layer can be heated up to 473K in a working high power WLEDs. Here, we have confirmed indeed a red luminescence of Mn4+ substituting for calcium sites rather than tetrahedral aluminum sites in CaAl4O7:Mn which can be synthesized in pure phase even with boron acid as flux, and examined the low and high temperature luminescent properties in the range of 10 to 500K. We have revealed as well as thermal quenching mechanism that distorted octahedral Mn4+ sites suffer severe thermal quenching. This work, thus, hints a strategy to find a new Mn4+ phosphor with better resistance to thermal impact in the future. (c) 2013 Optical Society of America