Near-Infrared Luminescence of Cr³⁺-Doped Ba₂NaNb₅O₁₅ Embedded in Transparent Glass-Ceramics as Solid-State Illumination for Night-Vision Imaging

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs), a widely used NIR light source, are typically prepared by sealing the NIR phosphor powder and an LED chip with epoxy resin. One issue that NIR pc-LEDs frequently encounter is the aging and deterioration of epoxy resin over time, which leads to self-absorption and a sharp decline in emission efficiency. Here, we report the synthesis of a chemically stable NIR luminescent material composed of Cr³⁺-doped Ba₂NaNb₅O₁₅ nanocrystals measuring 10-15 nm, with Cr³⁺ ions located in the octahedral centers of the nanocrystals. Under 460 nm light excitation, the transparent glass-ceramic exhibited a broadband NIR emission in the range of 600-1400 nm, which originated from the electronic transition of Cr³⁺ from the excited state of ⁴T₂ to the ground state of ⁴A₂. The emission peak was located at ∼810 nm, the FWHM was ∼230 nm, and the internal quantum efficiency reached ∼0.81%. We constructed a stable NIR pc-LED device using optimized transparent NIR-emitting glass-ceramics and a commercially available blue LED chip, demonstrating its promising application in night-vision lighting. Our study provides a basis for the preparation of transparent glass-ceramic-based NIR pc-LED devices as an improved alternative for solid-state illumination.