Ni²⁺-Doped Yttrium Aluminum Gallium Garnet Phosphors: Bandgap Engineering for Broad-Band Wavelength-Tunable Shortwave-Infrared Long-Persistent Luminescence and Photochromism

Abstract

Functional phosphors with shortwave infrared (SWIR) persistent luminescence have attracted an ever-increasing interest from scientists owning to the self-sustainable emission for deeper tissue penetration, real-time monitoring, and nondestructive analysis. In this work, we report for the first time on the broadband wavelength-tunable SWIR luminescence and photochromism properties of divalent nickel-doped yttrium aluminum gallium garnet solid solutions. The crystal-field-driven wavelength-tunable superbroad band emission within SWIR wavelength region, attributed to the 3 T 2 ( 3 F) → 3 A 2 ( 3 F) transitions of the Ni 2+ ions, can be controllably adjusted. The observation of SWIR longpersistent luminescence also can be modified by bandgap engineering via the simple adjustment of the Ga/Al ratio. Besides, the accompanied observation of photochromism, i.e., the reversible body color change by alternative UV and visible illumination/ heating treatment, shows robust fatigue resistance. The nature of traps, color centers, and trapping and releasing of electrons are studied by electron paramagnetic resonance and thermoluminescence. Finally, an energy level schematic diagram is established to discuss the SWIR persistent luminescence and photochromism mechanisms in detail. This work opens an avenue to motivate researchers to rationally design and purposely explore novel bifunctional phosphors with broad-band wavelength-tunable SWIR persistent luminescence and photochromism.

Solid‐State Thin‐Film Broadband Short‐Wave Infrared Light Emitters

“…The fundamental challenges in electronic level modification for optical transitions in the SWIR and low stability have hindered the development of SWIR emitting pc‐LEDs with broadband and highly efficient emission. [ 20,21 ] Here, we report a novel class of SWIR broadband thin‐film light‐emitter technology that simultaneously offers high efficiency, low cost, CMOS compatibility, and unprecedentedly broadband response across the SWIR exploiting a tandem multi‐bandgap colloidal quantum dot (CQD) stack.…”

Progress and Viewpoints of Multifunctional Composite Nanomaterials for Glioblastoma Theranostics

“…The range of the wavelength can also avoid autofluorescence efficiently. According to its bio-optical properties, NIR can be divided into 700-1000 nm, 1000-1350 nm, and 1550-1700 nm, known as the NIR-I, NIR-II, and NIR-III windows [39]. The development of NIR-I emission nanoprobes has matured and is widely used for bio-imaging, tracking, and distribution in vivo [40].…”

Optically Stimulated Luminescence Phosphors: Principles, Applications, and Prospects

“…[244,245] In 2007, for the first time, Chermont et al reported the preparation of nanoprobes (MgSiO 3 :Eu 2+ , Dy 3+ , Mn 2+ ) with near-infrared persistent luminescence for in vivo bioimaging. [246] Since then, more and more studies, including TM (Ni 2+ , Cr 3+ , Mn 2+ , Mn 4+ ), [17,75,[247][248][249][250] other metal ions (Bi 3+ ), [251] and Ln ions (Eu 2+ , Pr 3+ , Nd 3+ , Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ , Sm 3+ , Dy 3+ , Yb 2+ ), [59,163,[252][253][254][255][256][257][258] especially Cr 3+ ions doped inorganic micro/nanophosphors with NIR long persistent luminescence, have been reported and are being carried out. However, the persistent luminescence intensity of this kind of persistent phosphors always attenuates over time and finally disappears after the complete depletion of charge carriers from shallow traps.…”

“…The storage of photon energy is similar to that of thermally stimulated luminescence (TSL) except that the stimulation of OSL needs light while TSL requires heating. [8][9][10][11][12][13][14][15][16][17] Unfortunately, TSL inevitably suffers from serious "thermal quenching" at high temperature, which causes the decrease of luminescence intensity. [18,19] In contrast, OSL confers the all-optical features and operation mode at room temperature, and thus OSL materials show many incomparable advantages over TSL counterparts in various practical applications.…”