Broadband near-infrared luminescence from Fe3+-activated NaScSi2O6 phosphors for luminescence thermometry and night-vision applications

Broadband near-infrared (NIR) materials have recently evoked considerable interest for versatile applications, but the choices of efficient emitters for NIR phosphors are rather limited. Herein, an Fe³⁺-activated NaScSi₂O₆ phosphor has been successfully synthesized by a solid-state reaction method. A broad NIR emission band is observed at 900 nm when excited at 300 nm ultraviolet light, reaching a full-width at half maximum (FWHM) of 135 nm and an internal quantum efficiency (IQE) of 13.3%. The luminescence is related to 3d-3d transitions of Fe³⁺ in the octahedral site, and verifies the effectiveness of the Fe³⁺ activator in realizing efficient NIR emission. The emission intensity of Fe³⁺ ions shows a linear quenching tendency in the temperature range of 293-433 K. The feasibility of the as-synthesized phosphors in applications such as NIR luminescence thermometry and NIR patches was also investigated.