Novel powellite-based red-emitting phosphors: CaLa1-xNbMoO8:xEu(3+) for white light emitting diodes

摘要

We report the photoluminescence properties of a novel powellite-based red-emitting phosphor material: CaLa1-xNbMoO8:xEu(3+) (0.01, 0.03, 0.05, 0.1) for the first time. The photoluminescence investigations indicated that CaLa1-xNbMoO8:xEu(3+) emits strong red light at 615 nm originating from D-5(0)-> F-7(2) (electric dipole transition) under excitation either into the L-5(0) state with 394 nm or the D-5(2) state with 464 rim, that correspond to the two popular emission lines from near-UV and blue LED chips, respectively. When compared with emission intensity from a CaMoO4:Eu3+, the emission from CaLaNbMoO8:Eu3+ showed greater intensity values under the same excitation wavelength (394 nm). The enhanced red emission is attributed to the enhanced f-f absorption of Eu3+. These materials could be promising red phosphors for use in generating white light in phosphor-converted white light emitting diodes (WLEDs). (C) 2008 Elsevier Inc. All rights reserved.