Eu²⁺-actived oxyfluoride glass with highly efficient blue–cyan luminescence for X-ray imaging and white LED applications

Eu²⁺-doped glass has attracted considerable interest due to its dual functionality in X-ray imaging and white light-emitting diodes (LEDs). However, the amorphous nature of glass restricts the improvement of the luminescent efficiency of Eu²⁺-doped glass. Here, four strategies, including selecting oxyfluoride glass as the host, regulating optical basicity, introducing appropriate heavy elements, and adding carbon powders as reducing agents, were proposed to prepare Eu²⁺-doped glass with excellent X-ray excited luminescence (XEL) and efficient blue–cyan photoluminescence (PL). For scintillating performance, the optimal glass exhibits a record-breaking XEL intensity reaching 308% of that of commercial Bi₄Ge₃O₁₂. Together with high transmittance (> 80% at 472 nm), linear response to X-ray dose, and low detection limit (6.0 μGy_air/s), the imaging resolution based on optimal glass reaches 24 lp/mm. For PL performance, the intense blue–cyan light of the optimal glass possesses a high external quantum efficiency of 71.2% and excellent thermal stability (the PL intensity at 423 K is 57.7% of that at room temperature). When combined with the 400-nm chip, the optimal glass effectively fills the cyan gap and elevates the color rendering index of the white LED to 91.8. This work offers valuable guidelines and design principles for improving the XEL and PL performance of Eu²⁺-doped glass.