Tunable broadband near-infrared luminescence from Cr3+-doped gallium oxide-based phosphors for advanced sensing and LED applications

Abstract

Near-infrared (NIR) phosphor-converted light emitting diodes (pc-LEDs) highly demand broadband NIR phosphors for applications in food safety and smart detection. However, the lack of tunable NIR luminescent materials limits their development. Herein, we constructed a series of NIR Cr³⁺ doped Ga₂O₃-based materials with broadband, tunable, efficient emissions by utilizing [Zn²⁺–Ge⁴⁺] and [Ga³⁺–Ga³⁺] co-unit substitution. The obtained results show that the emission peak of NIR phosphors can be modulated from 713 to 765 nm. Meanwhile, the excitation peak remains in the blue light region. NIR phosphor-converted devices were prepared with 450 nm LED chips, which were studied using NIR imaging, penetration imaging, anti-counterfeiting, and pupil recognition technologies. Interestingly, NIR mechanoluminescence (ML) was realized based on the developed phosphors, which were successfully applied for non-destructive measurements of solids and in vivo bioimaging. Our study proposes a series of tunable and broadband luminescent materials and devices for NIR applications.