Pure cyan-emitting phosphor NaBaLuSi2O7:Eu2+ with high thermal stability for full-spectrum lighting

Full-spectrum lighting technology plays a crucial role in the development of advanced intelligent light source devices. However, achieving a reliable cyan emitter with both high color purity and minimal luminescence thermal degradation remains a significant challenge. This is mainly due to the lack of effective spectral modulation strategies and high-quality rigid host network structures. In this study, a luminescent Eu²⁺ cation center was incorporated into the tightly connected polyhedral NaBaLuSi₂O₇ host, resulting in an emission band centered at 479 nm under near-ultraviolet excitation, fully covering the cyan spectral region (450-520 nm). Importantly, the cyan emitter displayed improved thermal stability, attributed to its uniquely dense three-dimensional rigid structure, retaining 66% of its luminescence intensity at 473 K. Due to its exceptional cyan luminescence properties, the WLEDs device constructed by combining this emitter with three primary color phosphors achieved an exceptionally high color rendering index 96 and a low correlated color temperature 3731 K, highlighting its significant potential for full-spectrum lighting.