Bandgap Tailoring via Si Doping in Inverse-Garnet Mg3Y2Ge3O12:Ce(3+) Persistent Phosphor Potentially Applicable in AC-LED.

The state-of-the-art alternating-current light-emitting diode (AC-LED) technique suffers from adverse lighting flicker during each AC cycle. Aiming to compensate the dimming time of AC-LED, herein, we report a novel Mg3Y2(Ge1-xSix)3O12:Ce(3+) inverse-garnet persistent phosphor whose afterglow is efficiently activated by blue light with persistent luminescence in millisecond range. It is experimentally demonstrated that Si doping tailors the host bandgap, so that both the electron charging and detrapping in the persistent luminescence process are optimized. To explore the origin of the millisecond afterglow, we performed a series of thermoluminescence analyses, revealing three types of continuously distributed traps in the host. Finally, an AC-LED prototype device was fabricated, which exhibits the warm white emission with a reduced percent flicker of 71.7%. These results demonstrate that the newly developed persistent phosphor might be a promising candidate applicable in low flickering AC-LED which has advantages of cheaper price, longer lifetime, and higher energy utilization efficiency.