Broadband near-infrared emitting Sr3Sc4O9: Cr3+ phosphors: Luminescence properties and application in light-emitting diodes

Near-infrared (NIR) phosphors converted to light-emitting diodes (pc-LED) sources have extensive application prospects in medical imaging, foodstuff analysis and plant growth fields. However, there are some shortcomings in NIR phosphors, such as narrow emission band and poor thermal stability. Here a new wide band NIR luminescent phosphor Cr3+-doped Sr3Sc4O9 (SSO) is introduced. The emission spectrum ranges from 600 nm to 1000 nm, with a peak value of 761 nm and the value of full width at half maximum (FWHM) is 120 nm. The internal quantum efficiency (IQE) of sample is about 87% according to the fitting result. The most appropriate doping concentration is x = 0.02 and the best excitation wavelength is 468 nm, which matches the commercial blue chip. At the same time, the phosphor shows good thermal stability in variable temperature spectrum test, and can maintain 70.4% emission intensity at 373 K relative to room temperature. To better understand its practical applications, packaged pc-LED is designed to show good NIR light penetration in spectral penetration tests. This study provides an excellent choice of NIR phosphors.