Eu~(2+) and Mn~(2+) activated single phase white emitting phosphor Na(Sr,Ba)PO_4 for phosphor converted-LEDs

摘要

We synthesized and analyzed single-phased white light emitting phosphors, Na(Sr,Ba)PO_4:Eu , Mn , and found that the energy transfer from the Eu~(2+) to the Mn~(2+) activator followed by the photoemission was more efficient in Na(Sr_(0.5)Ba_(0.5))PO_4 than in the Ba-free host composition, NaSrPO_4. Combining a near UV 390 nm chip and the given Na(Sr_(0.5)Ba_(0.5))PO_4:Eu~(2+), Mn~(2+) phosphor produced a bright white light illuminating phosphor converted-light emitting diodes (pc-LEDs), demonstrating CIE chromaticity coordinates of (0.36,0.31). The emission intensity was substantially changed with an increase of the injection current from 5 to 90 mA, while the shifts of chromaticity coordinates were nearly negligible. Those results suggest that Na(Sr,Ba)PO_4: Eu~(2+), Mn~(2+) can be a promising single component phosphor for cost effective white emitting pc-LEDs.