Synthesis and photoluminescence properties of a novel BaGe4O9:Eu3+ red emitting phosphor for warm white LEDs

摘要

Novel BaGe4O9:Eu3+ red-emitting phosphors were synthesized by a high-temperature solid-state reaction. The crystal structures, morphological properties, elements analysis, optical properties and fluorescence decay time were investigated systematically. In contrast, the optimal Eu3+ -doping concentration is 30 mol% when monitored at 591 nm with a 394 nm excitation. The energy transfer of Eu3+ ions in BaGe4O9 host lattice is dominated by the exchange interaction with the critical distance (R-c) of 5.28 angstrom. As expected, the red-emitting phosphor BaGe3.7O9:0.3Eu(3+) exhibited a better quantum yield (QY) of 57.9% and an excellent lifetime of 2.25 ms. Consequently, the red-emitting phosphors BaGe3.7O9:0.3Eu(3+) revealed a promising performance in warm WLED device with the CIE coordinates of (0.4365, 0.4130), the color temperature (T-c) of 3079 K and the color rendering index (R-a) of 85.8 under a driven current of 20 mA. These results indicate that the BaGe4O9:Eu3+ phosphors are prospective candidates as red-light component for warm white light-emitting diodes (WLEDs) devices.