In Situ Glass Crystallization Enables Narrowband Blue Luminescence for Full‐Spectrum Lighting and Transparent Display

Abstract Currently, narrowband light‐convertor is critically urgent for preeminent color representation in lighting and display fields, however, the development of target materials still remains challenging. Herein, glass ceramic (GC) composite based on in situ glass crystallization, where the condense glass network structure acts as effective obstructors for long distance ion diffusion, is elaborately designed to inhibit activators’ multi‐sites occupation for acquiring narrowband emitting. Following this strategy, an unprecedented narrowband blue emission of Eu 2+ ‐activators with a peak at 447 nm and full‐width of half maximum (FWHM) of ≈30 nm is developed in a new type of Sr 5 (PO 4 ) 3 Cl (SPOCl) GC composite. The Eu 2+ ‐activators’ hindered diffusion inside the GC composite makes preferential and limit occupation of the [Sr1O 9 ] sites, enabling narrowband blue luminescence. Furthermore, the GC composite highlights remarkable performance in high‐power violet‐excitable full‐spectrum lighting and transparent display (TD) prototype fields, due to its high color purity (≈98.1%), photoluminescence quantum field (PLQY, ≈80.5%) and thermal stability (≈82.1%@150 °C). This work not only promotes the profound understanding of the relationship between light manipulation and glass crystallization, but also paves the way toward the implementation of high‐quality lighting and display of GC composites.