Near-Infrared Long Afterglow in Fe³⁺-Activated Mg₂SnO₄ for Self-Sustainable Night Vision

Abstract

The advent of near-infrared (NIR) afterglow in Cr 3+ -doped materials has stimulated considerable interest in technological applications owing to the sustainable emission of light with good penetrability. However, the development of Cr 3+ -free NIR afterglow phosphors with high efficiency, low cost, and precise spectral tunability is still an open question. Herein, we report a novel Fe 3+ -activated NIR long afterglow phosphor composed of Mg 2 SnO 4 (MSO), in which Fe 3+ ions occupy the tetrahedral [Mg−O 4 ] and octahedral [Sn/ Mg−O 6 ] sites, giving rise to a broadband NIR emission spanning 720−789 nm. On account of energy-level alignment, the electrons released from the traps show a preferential return to the excited energy level of Fe 3+ in tetrahedral sites through tunneling, leading to a single-peak NIR afterglow centered at 789 nm with a full-width at half-maximum (fwhm) of 140 nm. The highefficiency NIR afterglow, showing a record persistent time lasting over 31 h among Fe 3+ -based phosphors, is demonstrated as a self-sustainable light source for night vision applications. This work not only provides a novel Fe 3+ -doped high-efficiency NIR afterglow phosphor for technological applications but also establishes practical guidance for rational tuning of afterglow emissions.

All-inorganic Mn2+-doped metal halide perovskite crystals for the late-time detection of X-ray afterglow imaging

“…Despite tremendous efforts, the vast majority of studies have focused on real-time X-ray imaging for flat objects by virtue of their outstanding scintillation properties, while ignoring time-lapse X-ray imaging due to the lack of efficient afterglow MHPs. [20][21][22] Afterglow, a captivating phenomenon where a material can store light energy by capturing the electrons and/or holes, and then releasing them continuously at room temperature (RT) in the form of a selfsustained photon emission, [23][24][25][26][27][28] is commonly considered to be detrimental to a high-quality scintillator and needs to be avoided in practical applications. However, the utilization of afterglow in MHP scintillators offers incomparable merits, particularly for time-lapse offline X-ray imaging of curved objects, and long-term storage X-ray imaging in some harsh environments.…”

Structural confinement toward suppressing concentration and thermal quenching for improving near-infrared luminescence of Fe3+

“…Fe 3+ ions are characterized by their half-filled 3d 5 electronic configuration, and both octahedral and tetrahedral sites are suitable for Fe 3+ to exhibit NIR luminescence. 17 Similar to Cr 3+ ions, the emission wavelength of Fe 3+ ions can be easily tuned because the bare 3d electrons are susceptible to the host environment. 18 However, the d-d transition of Fe 3+ ions is strictly restricted by the Laporte selection rule, especially in highly symmetric fields, 14,19 and moreover suffers from a strong electron-phonon coupling effect, leading to the poor luminescence property of Fe 3+ ions.…”

Bi3+/Sm3+ co-doped LiTaO3 photochromic perovskites: an ultrafast erasable optical information storage medium

“…This property is called persistent luminescence (PersL) or long afterglow. 32,33 PersL materials have attracted much attention in the fields of night vision surveillance, 34,35 anti-counterfeiting identification, 36,37 and information storage 38,39 due to their unique delayed luminescence characteristics. We envisage that if we can combine photochromic and delayed luminescence properties in a single material, it will be able to write and read data in both light and dark fields, significantly improving the applicability of information storage media.…”