Breaking Through the Luminescence Stability Bottleneck of Oxyfluoride Phosphor for Sun-Like Led Lighting

Sunlight like optical source is the primary objective of healthy lighting. In contrast, achieving full spectrum lighting with high stability remains challenging, mostly due to the scarcity of purple chip-pumped cyan-green phosphors and their inherent emission instability. In this study, a novel strategy is presented that realizes simultaneous enhancements in both humidity stability (increased by 2.9 times) and luminescence quantum efficiency (enhanced by 1.5 times) for cyan-emitting Sr₃AlO₄F:Ce³⁺ phosphor by employing Si/N doping. Theoretical modelling shows that these improvements are attributed to the regulation of energy bands and structural rigidity as well as modulation of the ionicity of chemical bonds. Furthermore, blending the other violet chip-pumped phosphors, sun-like LEDs that accurately replicate solar spectra in different times of the day with an optimal color rendering index of 99 is successfully engineered. Moreover, the universality of this strategy on other oxyfluoride phosphors has also been validated. This groundbreaking outcome offers a practical solution to overcome the inherent luminescence stability limitations in oxyfluoride phosphors, thus catalyzing the application of these cyan-green candidates in sun-like LED lighting.