Realizing Color‐Tunable and Time‐Dependent Ultralong Afterglow Emission in Antimony‐Doped CsCdCl₃ Metal Halide for Advanced Anti‐Counterfeiting and Information Encryption

Abstract

Long afterglow luminescent materials have captured intense attention for their unique applications in biological imaging, photodynamic therapy, and optical anti-counterfeiting. However, achieving highly efficient and tunable ultralong afterglow emission in all-inorganic metal halides is an open challenge. Herein, Sb 3+ -doped hexagonal CsCdCl 3 metal halide is reported via hydrothermal reaction. Upon photoabsorption, the as-synthesized compounds exhibit dual-emission bands with a photoluminescence quantum yield (PLQY) of 59.6%, which can be attributed to the self-trapped exciton emission out of the strong electron-phonon coupling. After ceasing excitation of 365 nm, bright afterglow emission with the longest duration lasting up to 5000 s is witnessed in Sb 3+ -doped CsCdCl 3 . More importantly, the color-tunable and time-dependent ultralong afterglow emission is realized via regulating the doping concentration of Sb 3+ , which should be due to the trap electrons increase gradually under high doping concentration. Given this unusual afterglow emission characteristics, the optical anti-counterfeiting and information encryption are constructed based on as-synthesized compounds. These findings not only help further understand the tunable afterglow emission mechanism in all-inorganic metal halides, but also provide a new strategy for designing novel ultralong afterglow luminescent materials.

Enhancing Luminescence in Hue-Tunable White-Light Emitting K4CdCl6:Sb3+,Mn2+ All-Inorganic Halide Perovskites: Insights from Defect Engineering and Energy Transfer

“…In Figure S16, the excitation spectrum of KCdCl 3 :Sb 3+ monitored at 554 nm exhibits three bands in the 250−400 nm region, similar to that of CsCdCl 3 :Sb 3+ in previous work. 14 Under excitation at 285, 340, and 327 nm, the emission spectra of KCdCl 3 :Sb 3+ indicate a similar profile with a broad emission covering 400−700 nm. The results demonstrate that there is only one PL center in the KCdCl 3 :Sb 3+ .…”

“…Many derivatives of Cd-based AIHPs have been developed host lattices for various luminescent materials through the substituting the Cd 2+ with different dopants, such as Sb 3+ , Sn 2+ , and Mn 2+ (Table S1). − ,− The Sb 3+ and Mn 2+ -codoped 2D AIHPs Cs 3 Cd 2 Cl 7 :Sb 3+ ,Mn 2+ have ultralong afterglow emission at 579 nm. The Sb 3+ /Mn 2+ doped the hexagonal CsCdCl 3 AIHPs lead to red/orange afterglow emission with the longest duration after removal of the UV excitation, which is expected for application in biological imaging, photodynamic therapy, and optical anticounterfeiting. ,, The Cs 2 CdCl 4 :Sb 3+ nanoplatelets exhibit cyan emission with photoluminescence quantum yield (PLQY) of 20%, highlighting the potential of colloidal chemistry methods to study the full diversity of Ruddlesden–Popper phases .…”

“…The incorporation of Sb 3+ ions in AIHPs is known to induce broad emissions spanning from the blue to the NIR region due to the softening effect of Sb 3+ ions on the structural lattice. This effect enhances the efficiency of self-trapped excitons (STEs), leading to significant advancements in Sb 3+ -triggered photoluminescence AIHPs. − ,, However, understanding the origin of Sb 3+ photoluminescence remains challenging, requiring further elucidation of the contribution of atomic orbitals in the valence band maximum (VBM) and conduction band minima (CBM) of the AIHPs. Additionally, investigating the composition-dependent luminescence and defect chemistry induced by heterovalent doping is crucial for guiding the design of novel photoluminescent AIHPs.…”

“…The Sb 3+ /Mn 2+ doped the hexagonal CsCdCl 3 AIHPs lead to red/orange afterglow emission with the longest duration after removal of the UV excitation, which is expected for application in biological imaging, photodynamic therapy, and optical anticounterfeiting. 4,14,15 The Cs 2 CdCl 4 :Sb 3+ nanoplatelets exhibit cyan emission with photoluminescence quantum yield (PLQY) of 20%, highlighting the potential of colloidal chemistry methods to study the full diversity of Ruddlesden−Popper phases. 5 The incorporation of Sb 3+ ions in AIHPs is known to induce broad emissions spanning from the blue to the NIR region due to the softening effect of Sb 3+ ions on the structural lattice.…”

Afterglow Phosphor Goes Transparent

“…Apart from the double perovskites, CsCdCl 3 has emerged as a novel afterglow material recently. ,,,− He et al first reported a hexagonal-phase Mn 2+ -doped CsCdCl 3 perovskite with a long afterglow duration up to 1480 s . Despite the rich traps, a high PL QY up to 91.4% was realized by adjusting the doping concentration of Mn ions.…”