Enhancing Quantum Efficiency of Narrow Band Green Emitting Phosphor SrGa2S4:Eu2+ via Solid Solution Engineering for Wide Color Gamut Display

The pursuit of high-performance narrow-band green phosphors is crucial for wide color gamut displays including liquid crystal displays and laser-driven displays. SrGa 2 S 4 :Eu 2+ is a well-established narrow-band green-emitting phosphor, but its low external quantum efficiency (EQE) limits its practical application. Herein, Mg 2+ doping strategy is employed to enhance the EQE of SrGa 2 S 4 :Eu 2+ , significantly improving in its EQE from 33.1% to 53.1%. This improvement is attributed to enhanced lattice rigidity induced by Mg 2+ doping, which suppresses lattice vibrations, thereby reducing energy loss via phonon coupling and increasing the probability of radiative emission. This effect is corroborated by Raman spectroscopy, which reveals a shift in vibrational modes consistent with increased rigidity. To evaluate its practical applicability, we integrated the newly obtained narrow green-emitting phosphor into liquid crystal displays (LCDs) and laser-driven projection systems. Prototype tests demonstrate that displays utilizing (Sr,Mg)Ga 2 S 4 :Eu 2+ deliver significantly more vivid and color-saturated images compared to those employing the conventional broad-spectrum yellow-emitting Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) phosphor. These results fully underscore the great potential of the modified phosphor for wide-color-gamut display applications.