Efficient and broadband near-infrared emitting Ca2YHf2Ga3O12: Cr3+ phosphor for anti-counterfeiting applications

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) as efficient and compact light sources widely used in fields such as medicine, food safety, night vision, and more. However, most NIR phosphors manifest drawbacks, including relatively narrow FHWM, low photoluminescence quantum efficiency, and poor thermal and chemical stability, which limit their effectiveness in broadband applications. Therefore, a key challenge lies in designing an NIR phosphor combining a broad emission bandwidth with high quantum efficiency and excellent Thermal stability. A broadband NIR phosphor Ca₂YHf₂Ga₃O₁₂: Cr³⁺ (CYHG: Cr³⁺) was explored. The peak emission of the material occurs at 794 nm, with an FWHM of 189 nm covering 700–1100 nm. The best-performing phosphor presents the internal and external quantum efficiencies (IQE/EQE) of 82 % and 22 %, respectively. At 423 K, its luminescence remains at roughly 60 % of its room-temperature intensity. Utilizing its superior optical properties, a prototype NIR pc-LED incorporating CYHG: Cr³⁺ was developed to assess its practical feasibility. The resulting device, functioning as a compact and broadband NIR source, delivered 62 mW output at 380 mA, making it suitable for applications such as night vision, non-destructive testing, and anti-counterfeiting.