Crystal structure and luminescence properties of a novel near-infrared phosphor LiAlO2:Fe3+

Cr3+-free near-infrared (NIR) phosphors are currently gaining significant attention in various application fields. A novel Fe3+-activated LiAlO2 NIR phosphor was successfully synthesized by high-temperature solid-state method. Under excitation of 391 nm and 467 nm, the phosphor emits near-infrared light with wavelengths ranging from 600 to 850 nm. The emission bands with peaks at 725 nm correspond to the transition from 4T1(4G) to the ground state energy level 6A1(6S). The optical band gap of LiAlO2 was calculated using Density Function Theory (DFT) and diffuse reflectance spectrum, respectively. The thermal stability of the sample was measured under 391 nm and 467 nm excitation, showing that the emission intensity at 413 K is 55.3 % and 52.4 % of the emission intensity at room temperature.