Luminescence properties of Pr6O11-doped and PrF3-doped germanate glasses for wideband NIR phosphor

We have synthesized 0.12Pr6O11–45Sb2O3–10ZnO–45GeO2 glass and 0.72PrF3–45Sb2O3–10ZnO–45GeO2 as a wideband near-infrared phosphor for LED-based light-sources. We have achieved an ultra-wideband luminescence from 700 to 1100 nm from both samples. Luminescence intensity around 730 nm (3P0 → 3F4 transition) was lower than that around 1040 nm (1D2 → 3F4 transition) in the Pr6O11-doped sample. On the other hand, luminescence intensity around 730 nm was higher than that around 1040 nm in PrF3-doped sample. These results indicated that a phonon energy around Pr3+ ions should be decreased by substituting PrF3 for Pr6O11. An output power of the PrF3-doped sample was 1.5 times higher than that of the Pr6O11-doped sample. A measured fluorescence lifetime of 1D2 level in the PrF3-doped sample was shorter than that in the Pr6O11-doped one. These results indicated that oxide glasses doped with rare-earth fluoride should be useful for our practical wideband NIR phosphor.