The effects of Lu 3+ , Gd 3+ and Ga 3+ substitution on the photoluminescence of Y 2.95- x - y Lu x Gd y Al z Ga 5- z O 12 :0.05Ce 3+ phosphors for high-power white AC-LEDs

Various yellowish-green persistent phosphors of Y Lu Gd Al Ga O :0.05Ce ( = 0-1, = 0-1, = 1-4) were successfully synthesized by the one-step high-temperature solid-state reaction method in air. The effects of simultaneous doping of Lu , Gd and Ga on the luminescence properties of the phosphors were investigated in detail for the first time. Herein, the microstructure, morphology, afterglow performance, luminescence properties, thermoluminescence, thermal quenching and flicker index of the efficient blue-light-activated Y Lu Gd Al Ga O :0.05Ce phosphors were tested. The and values of Y LuGd Al Ga O :0.05Ce are 10.8 ms and 33.2 ms, respectively. These parameters are important in terms of effectiveness in reducing flicker in alternating current (AC) LEDs. Compared with the conventional Y Al Ga O :Ce phosphor, the Y LuGd Al Ga O :0.05Ce phosphor has a better luminescence performance, stronger afterglow performance, and lower flicker index. The quantum yield of the Y LuGd Al Ga O :0.05Ce phosphor was 86.42% and the luminous efficiency of the LED devices prepared with it reached 92.12 lm W when operated at 100 mA. Integrating sphere and spectroradiometer tests as well as CIE chromaticity diagrams indicate that the AC-WLEDs assembled by mixing the Y LuGd Al Ga O :0.05Ce phosphor and a commercial red phosphor in an appropriate ratio could obtain ideal white light with a high color-rendering index (87.9) and the flickering index was successfully reduced from 100% to 61.4%.