The VUV-vis luminescent properties of NaYFPO_4: Dy~(3+) phosphor

摘要

Dy ~(3+)-doped monoclinic NaYFPO_4 phosphor has been synthesized by solid-state reaction technique. Its photoluminescence in the vacuum ultraviolet (VUV)-visible region was investigated. The most intensity broadband emission centered at about 171 nm was the host-related absorption. Another broadband at 153 nm could be related to the O_2→Dy~(3+) charge transfer band (CTB) absorption. The excitation peaks located at 178 nm and 256 nm were the spin-allowed (SA) and spin-forbidden (SF) fd transitions of Dy~(3+), respectively. Some sharp lines in the range of 280500 nm were due to the ff transitions of Dy~(3+) within its 4f~(9) configuration. Under the VUV-vis excitation, the Dy~(3+)-doped NaYFPO_4 phosphor showed the characteristic emissions of Dy~(3+) (~4F_(9/2)→ ~6H_(15/2)transitions and ~4F_(9/2)→ ~6H_(13/2) transitions) with a stronger blue emission peaking at about 485 nm. All the chromaticity coordinates of the sample were in the near cold-white region. It can be predicted that this phosphor can be applied in both mercury-free luminescence lamps and white LED.