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.

This work highlights a novel double-perovskite red phosphor Gd2ZnTiO6:Mn4+for UV-based warm white LEDs.

Supporting informationTable 1.R-values of structrue refined by fullprof of six different Sc 3+ tridoping concentration samples.

A novel Na2WO2F4:Mn4+red-emitting phosphor, exhibiting an ultra-intense zero phonon line at 620 nm, is demonstrated to be promising for LED lightings and displays.

The advent of wide color‐gamut LED backlight technology greatly improves the user experience in visions. The bottleneck restricting progress of this technology is to develop red phosphor with satisfactory spectral features and low cost. Herein, a novel non‐rare‐earth K2XF7:Mn4+ (X = Ta, Nb) was successfully designed and synthesized, exhibiting an admirable quantum efficiency of ∼93.5%, an extremely narrow FWHM of ∼2.3 nm, and a high color purity of ∼99.6%. Unlike the previously reported Mn4+ activated fluorides, Mn4+ in K2XF7 suffers highly distorted octahedral environment in C1 (or C2v) group symmetry, enabling the appearance of intense zero phonon line and distinctive vibronic transitions. Systematical high‐resolution spectroscopic analyses down to 10 K disclose the influences of strong crystal field, weak nephelauxetic effect, and intermediate electron‐phonon coupling are responsible for the peculiar spectral features of Mn4+ in K2XF7. Impressively, a wide color‐gamut reaching up to 86.7% NTSC is realized, demonstrating great validity of K2XF7:Mn4+ for LCD backlights. The present study not only brings a brand‐new kind of Mn4+ activated host to the sight of phosphor community (the host can be extended to surges of tantalum/niobium fluorides), but also may enlighten researchers to design highly distorted environment to achieve unique spectral properties of Mn4+.