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 broad-band 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 ³T₂(³F) → ³A₂(³F) transitions of the Ni²⁺ ions, can be controllably adjusted. The observation of SWIR long-persistent 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.

中文翻译：

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Ni ²⁺掺杂钇铝镓石榴石荧光粉：宽带隙可调谐短波红外长持续发光和光致变色的带隙工程

具有短波红外（SWIR）持续发光功能的磷光体吸引了越来越多的科学家兴趣，他们希望拥有可自我持续发光的特性，以实现更深的组织穿透，实时监控和无损分析。在这项工作中，我们首次报告了二价镍掺杂钇铝镓石榴石固溶体的宽带波长可调SWIR发光和光致变色特性。Ni ²⁺的³ T ₂（³ F）→ ³ A ₂（³ F）跃迁归因于SWIR波长范围内的晶体场驱动波长可调超宽带发射离子，可控地调节。带隙工程也可以通过简单地调整Ga / Al比率来修改SWIR长持续发光的观察结果。此外，伴随观察到的光致变色现象，即通过替代的紫外线和可见光照射/加热处理可逆的车身颜色变化，显示出强大的抗疲劳性。通过电子顺磁共振和热致发光研究了陷阱的性质，色心以及电子的俘获和释放。最后，建立了能级示意图以详细讨论SWIR持续发光和光致变色机理。