Wideband near-infrared luminescence in Al5BO9: Cr3+, Ga3+ phosphor for near-infrared spectroscopy application

Cr³⁺-activated near-infrared (NIR) light sources have witnessed substantial application in night vision and biomedical imaging. However, enhancing the emission efficiency and thermostability of Cr³⁺-doped NIR emitting materials remains a challenge. Herein, Al₅BO₉: Cr³⁺, Ga³⁺ phosphor was synthesized via the solid-state sintering methodology. Upon 400 nm photoexcitation, the developed phosphor emitted a narrow band at 697 nm accompanied by a broad NIR profile peaking at 750 nm. Remarkably, the system achieved an optimal internal quantum efficiency (IQE) of 61.45 %, and superior thermostability (83.1 % @ 373 K) relative to ambient conditions. The prototype of a packaged NIR phosphor-converted LED (pc-LED) revealed that the Al₅BO₉: Cr³⁺, Ga³⁺ phosphor delivered 140 mW NIR radiation power at 320 mA driving current, and the corresponding photoelectric conversion efficiency reached 13.65 %. The performance of the packaged NIR pc-LED in practical demonstrations further substantiated the phosphor's potential for application in biological imaging and NIR night vision, highlighting its promising prospects.