Photoluminescence properties of Eu2+–Mn2+ codoped Ca-α-SiAlON phosphors

Eu2+–Mn2+ codoped Ca-α-SiAlON phosphors, Ca0.736−ySi9.6Al2.4O0.8N15.2:0.064 Eu2+, yMn2+, were firstly synthesized by the high temperature solid state reaction method. The effects of doped Eu2+ and Eu2+–Mn2+ concentrations on the photoluminescence properties of the as-prepared phosphors were investigated systematically. Powder X-ray diffraction shows that pure Ca-α-SiAlON phase is synthesized after sintering at 1700 °C for 2 h under 0.5 MPa N2 atmosphere. The excitation spectra of Eu2+-doped Ca-α-SiAlON phosphors are characterized by two dominant bands centered at 286 nm and 395 nm, respectively. The photoluminescent spectrum of Eu2+-doped Ca-α-SiAlON phosphor exhibits an intense emission band centered at 580 nm due to the allowed 4f 65d→4f 7 transition of Eu2+, showing that the phosphor is a good candidate for creating white light when coupled to a blue LED chip. The intensities of both excitation and emission spectra monotonously decrease with the increment of codoped Mn2+ content (i.e. y value), indicating that energy transfer between Eu2+ and Mn2+ is inefficient in the case of Eu2+–Mn2+ codoped Ca-α-SiAlON phosphors.