Luminescence Luminescence and theoretical calculations of novel red-emitting NaYPO4F:Eu3+ phosphor for LED applications

摘要

A novel red-emitting garnet NaYPO4F:Eu3+ phosphor was synthesized by a high-temperature solid-state method. The crystal structure, emission/excitation spectra, as well as decay curves and thermal stability were investigated in this paper. The excitation spectra varied with the Eu3+ concentration and consisted of one broad and three sharp intense, and several weak peaks. The broad band was assigned to the Eu3+-O2- charge transfer band (CTB) and this CTB has a continuous red-shift with increasing Eu3+ concentration. The sharp bands are related to the 4f-4f transitions of Eu3+ ions in the host lattice. The emission spectra show that the dominated peak at 609 nm corresponds to the D-5(0) -> F-7(2) transitions of Eu3+. The optimal Eu3+-doped concentration in NaYPO4F was found to be 20 at%. The luminescence decay lifetimes of NaYPO4F:xEu(3+) phosphors were in the range of 2.43 to 1.74 ms. The thermal stability indicated that the luminescence only decay 21% at 150 degrees C and decay 35% at 250 degrees C, respectively. (C) 2017 Elsevier B.V. All rights reserved.