KBaBP2O8: Eu2+ : A novel near-ultraviolet converting blue phosphor for white light-emitting diodes

A series of Eu2+-doped borophosphate phosphors, KBa1-xBP2O8: xEu(2+), were first synthesized via high-temperature solid-state reactions. The crystal structure, luminescence properties and concentration quenching of the as-prepared phosphors were systematically investigated. The results indicated that KBa1-xBP2O8: xEu(2+) phosphors could be efficiently excited by the near-ultraviolet to realize a novel blue luminescence corresponding to the electric-dipole allowed 4f-5d transition of the Eu2+ ions. Based on the theoretical calculation, the dipole-dipole interaction was dominantly involved in the mechanism of concentration quenching of Eu2+ in the phosphors, and the critical distance (R-c) was determined to be 22.77 angstrom. Additionally, the crystallographic site-occupation of the Eu2+ ions in the host was assigned and one Eu2+ site was confirmed in terms of photoluminescence spectra. In view of the preferable excitation spectrum profile and the intense blue emission peaking at 445 nm, the Eu2+-doped KBaBP2O8 phosphor is expected to find applications as a new blue-emitting phosphor for phosphor-converted light-emitting diodes. (C) 2012 Elsevier B.V. All rights reserved.