Luminescent properties of CaAl4O7 powders doped with Mn4+ ions

In this work, the effects of firing conditions, the Mn concentration, and a flux on the structural and luminescent properties of Mn4+ ion doped CaAl4O7 (CA2) powders were investigated. The photoluminescence excitation spectra of CA2:Mn4+ powders exhibited a broad band, covering from around 320 to 400 nm. Four red emission bands were observed at around 644, 656, 666, and 671 nm, while the 656 nm emission was observed as the strongest one. CA2:Mn4+ was believed to be a good candidate as a red phosphor for white light emitting diodes (LEDs) using near ultraviolet chips.