A Study on the Luminescence and Energy Transfer of Single-Phase and Color-Tunable KCaY(PO₄)₂:Eu²⁺,Mn²⁺ Phosphor for Application in White-Light LEDs

Abstract

Novel single-phased white light-emitting KCaY(PO(4))(2):Eu(2+),Mn(2+) phosphors for light-emitting diode (LED) applications were synthesized by conventional solid-state reaction. The emission hue could be controlled by tuning the Eu(2+)/Mn(2+) ratio via the energy transfer; the the emission hue of KCaY(PO(4))(2):Eu(2+),Mn(2+) varied from blue (0.1853, 0.2627) to white-light (0.3350, 0.3203) and eventually to purple (0.3919, 0.2867). The mechanism of energy transfer from a sensitizer Eu(2+) to an activator Mn(2+) in KCaY(PO(4))(2):Eu(2+),Mn(2+) phosphors was demonstrated to be an electric dipole-quadrupole interaction. Combining a NUV 405-nm chip and a white-emitting KCaY(PO(4))(2):1%Eu(2+),4%Mn(2+) phosphor produced a white-light NUV LED, demonstrating CIE chromaticity coordinates of (0.314, 0.329) and a color temperature of 6507 K.