Photoluminescence of Red-Emitting Phosphor Sr_2CeO_4: Eu~(3+), Sm~(3+) for Light-Emitting Diodes

摘要

The red-emitting phosphor Sr_2CeO_4: Eu~(3+), Sm~(3+) was synthesized by conventional high-temperature solid-state method. X-ray diffraction, and photoluminescence spectra were used to characterize the as-synthesized phosphor. In Eu~(3+) singly doped Sr_2CeO_4 phosphors, Eu~(3+) ion showed a weaker 7F0-5L6 transition at 395 nm with a narrow line and could not be efficiently excited by the NUV-LED chip. In Sm~(3+), Eu~(3+) co-doped Sr_2CeO_4 phosphors, the energy transfer from Sm~(3+) to Eu~(3+) in Sr_2CeO_4 host is observed and investigated in detail. The absorption band around 404nm was broadened and the intensities of the main emission line (5D0→7F2 transition of Eu~(3+) at 614nm) were strengthened because the energy transfer from Sm~(3+) to Eu~(3+). Moreover, The chromaticity coordinates of Sr_2CeO_4: Sm~(3+) can be regulated to approach the NTSC standard values of red phosphor by codoping Eu3+ ions. The photoluminescence properties suggest that novel Sr_2CeO_4: Eu~(3+), Sm~(3+) phosphor might have a potential research value on white-LEDs.