The exploration of high-performance near-infrared phosphors has attracted widespread attention. In this work, a brand new Rb₂LiAlF₆:Cr³⁺ (denoted as RLAF:Cr) phosphor has been constructed by the substitution of Al³⁺ ions with Cr³⁺ ions. Evidence shows that two sets of near-infrared emission bands, which originated from two types of Cr³⁺ sites, were observed upon blue light excitation. These emission bands merged into a wide emission band locating in the region of 650 nm–1050 nm, with a full width at half maximum (FWHM) of 125 nm. In addition, a high quantum efficiency of 77.7% and an excellent thermal stability at 417 K, with a retention rate of 90.5% of that at room temperature (RT), were witnessed. Profiting from the luminescence properties of the NIR phosphor, clear images of biological tissues and human palm veins were obtained using a light-emitting diode (LED) as a lighting source, which was constructed using an RLAF:Cr phosphor and a blue InGaN chip. These images showed the large potential of the RLAF:Cr phosphor for night vision and bioimaging in LED devices.

中文翻译：

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合理设计双位点 Rb2LiAlF6:Cr3+ 荧光粉的宽近红外发射，具有高效率和热稳定性，适用于光谱应用

高性能近红外荧光粉的探索引起了广泛关注。本工作通过Cr ³⁺离子取代Al ³⁺离子构建了一种全新的Rb ₂ LiAlF ₆ :Cr ³⁺ (记为RLAF:Cr)荧光粉。有证据表明，在蓝光激发下观察到两组近红外发射带，它们源自两种类型的Cr ³⁺位点。这些发射带合并成位于 650 nm–1050 nm 区域的宽发射带，半峰全宽 (FWHM) 为 125 nm。此外，其量子效率高达 77.7%，在 417 K 下具有优异的热稳定性，在室温 (RT) 下的保留率为 90.5%。得益于近红外荧光粉的发光特性，使用 RLAF:Cr 荧光粉和蓝色 InGaN 芯片构建的发光二极管 (LED) 作为光源，可以获得生物组织和人手掌静脉的清晰图像。这些图像显示了 RLAF:Cr 荧光粉在 LED 设备中用于夜视和生物成像的巨大潜力。