Garnet-structured Y2CaGa4ZrO12:Cr3+ NIR phosphor with combined high efficiency and thermal stability toward constructing high-performance pc-NIR-LED

Broadband near-infrared (NIR) emission phosphor with combined high external quantum efficiency (EQE, >30%) and excellent thermal stability requires further inquiry. The crystal/band structure analysis using X-ray diffraction (XRD), diffuse reflectance spectra, and density functional theory (DFT) calculation for the Y 2 CaAl 4− x Ga x ZrO 12 garnets yielded a suitable x  = 4.0 host for the exploration of the novel Y 2 CaGa 4− y ZrO 12 : y Cr 3+ (YCAGZO:Cr) NIR phosphors. The comprehensive investigation using Rietveld refinement and photoluminescence spectroscopy produced the optimal YCAGZO:Cr ( x  = 4.0, y  = 0.04) phosphor with wideband NIR emission (center at ∼764 nm, bandwidth ∼137 nm), high EQE= 32.0% (absorption efficiency ∼43.3%), and outstanding thermal stability ( I 423 K / I 298 K =90.0%, Δ E a =0.36 eV). Further, the satisfactory luminescence (NIR output power of 34.78 mW and photoelectric conversion efficiency of 12.42% at 100 mA) and imaging performance of the fabricated pc-NIR-LED using this optimal garnet phosphor prove that this newly developed phosphor is a promising choice for constructing the pc-NIR-LED devices used in scenarios such as food quality detection, noninvasive medical inspection, and night vision.