High-efficiency and thermally stable Cr3+-doped BaSiF6 fluoride phosphors for broadband near-infrared LED applications

Broadband near-infrared (NIR) light sources have emerged as crucial components in a wide array of technological applications, spanning from advanced imaging systems to night vision devices and healthcare therapy. The advent of light-emitting diodes (LEDs) has unlocked new opportunities for broadband NIR phosphor-converted LEDs (NIR pc-LEDs), characterized by improved efficiency, compact form factors, and low operating temperatures. However, high-performance NIR phosphors for high-power LEDs remain scarce. In this work, Cr 3+ -doped fluorides BaSiF 6 : x Cr 3+ (where x ranges from 2.5 % to 15 %) have been designed and synthesized, which offer high quantum efficiency and thermal stability to maintain ∼80 % intensity at 450 K. Theoretical simulations demonstrate that BaSiF 6 , with a sufficiently large electronic bandgap of 7.8 eV, possesses the full potential to host NIR luminescent activators. Furthermore, molecular dynamics (MD) simulations validate its good thermal stability , enduring high temperatures exceeding 600 K annealing. The fabricated NIR pc-LED device using BaSiF 6 :Cr 3+ demonstrates high light output power and photoelectric efficiency under multiple driven currents, making it suitable for a wide range of applications as NIR light source. Capitalizing on the above merits, a prototype NIR transmission detector is demonstrated for potential applications in non-invasive material inspection and security systems. This research expands the repertoire of high-performance NIR phosphors for multifunctional use. • Novel broadband NIR phosphors BaSiF 6 :xCr 3+ were synthesized. • DFT simulation suggests a notable thermal stability of BaSiF 6 :xCr 3+ . • BaSiF 6 :xCr 3+ can preserve 80 % luminescence intensity at 450 K. • NIR pc-LEDs fabricated for non-invasive optical inspection.