A broad-band orange-yellow-emitting Lu2Mg2Al2Si2O12: Ce3+ phosphor for application in warm white light-emitting diodes

摘要

A new garnet-type Lu2Mg2Al2Si2O12 compound was successfully synthesized via high-temperature solidstate reaction. The crystal structure was confirmed by the Rietveld refinement method and belongs to a cubic system with a space group of Ia (3) over bard (230) and cell parameters of a = b = c = 11.88310(1) degrees A. There are two different crystallographic positions for Mg2+ with coordination numbers of eight and six, respectively. A relatively large band gap (4.83 eV) was estimated by the diffuse reflectance spectrum, indicating that Lu2Mg2Al2Si2O12 may be a promising host matrix for luminescent materials. The synthetic Ce3+-doped Lu2Mg2Al2Si2O12 phosphor shows intense and broad-band orange-yellow emission peaking at about 575 nm under near-ultraviolet (n-UV) and blue light excitation. Additionally, the quantum efficiency, thermal stability, and packing performance were investigated to evaluate the practical use in white LEDs. The results indicate that Lu2Mg2Al2Si2O12: Ce3+ may be a promising orange-yellow phosphor for warm white LEDs.