Synthesis, luminescent properties and white light emitting diode application of Ba7Zr(PO4)6:Eu2+ yellow-emitting phosphor

A yellow-emitting phosphor, Eu2+-activated Ba7Zr(PO4)6 phosphor was synthesized by solid-state reaction method and the luminescence properties were investigated. The phosphor exhibited strong absorption in near ultraviolet (n-UV) region, which matched well with the n-UV chip. Upon excitation at 370 nm, the Ba7Zr(PO4)6:Eu2+ phosphor has a broad yellow emission band with a peak at 585 nm and a full width at half maximum of 178 nm wider than that of the commercial yellow-emitting YAG:Ce3+ phosphor. The mechanism of concentration quenching of Eu2+ ions in Ba7Zr(PO4)6 phosphor is verified to be energy transfer among the nearest neighbor Eu2+ ions. The CIE value and temperature dependence of photoluminescence were also discussed. Furthermore, a white-LED was fabricated using a 370 nm UV chip pumped with a blend of phosphors consisting of yellow-emitting Ba6.97Zr(PO4)6:0.03Eu2+ and blue-emitting BaMgAl10O17:Eu2+ phosphors, which achieved a CIE of (0.3329, 0.3562) with a color-rendering index of 86.4 around the CCT of 5487 K.