White light emission from NaLa(PO3)(4): Dy3+ single-phase phosphors for light-emitting diodes

White light emission phosphors NaLa(PO3)(4): Dy3+ were synthesized by a solid-state method. XRD analysis confirmed that all the Dy3+ doped phosphors are single phase. The photoluminescence excitation and emission spectra, concentration effect, decay property, and CIE coordinates were investigated. Strong excitation peaks of NaLa(PO3)(4): Dy3+ were found around 350-400 nm, which matched well with those of the near-UV LED chips. Under 350 nm excitation the NaLa(PO3)(4): Dy3+ exhibits intense white emission by combining the two emission peaks at 485 nm and 571 nm, attributed to the characteristic F-4(9/2)-H-6(15/2) and F-4(9/2)-H-6(13/2) transitions of Dy3+. The optimum doped concentration of Dy3+ ions is around 6 mol% and the critical transfer distance of Dy3+ is calculated as 15.4 angstrom. In addition, the CIE chromaticity coordinates of NaLa(PO3)(4): Dy3+ phosphors are (0.2923,0.3359). The results indicate that the NaLa(PO3)(4): Dy3+ phosphors have great potential as a single-component white-light-emitting phosphor for UV-light-emitting diodes. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.