As a promising lead-free metal halide, CsZnCl has the potential to serve as a host for achieving various photoluminescence emissions with different colors through ion doping. Therefore, studying the optical properties of various ions doped into CsZnCl with tetrahedron coordination is of great significance. However, there is still a lack of research on near-infrared (NIR) emission in CsZnCl. In this study, we successfully synthesized CsZnCl:Cr crystals using a simple hydrothermal method. The CsZnCl:Cr exhibits luminescence in the range of 800–1300 nm, with a peak position at 915 nm and a full width at half maximum (FWHM) of 150 nm under 375 nm excitation. Through the analysis of photoluminescence spectra, density functional theory (DFT), lifetime decay curves, temperature-dependent spectra, and time-resolved photoluminescence (TRPL), we confirmed the presence of two potential sites for Cr ion occupancy. Additionally, NIR phosphor-converted light-emitting diodes (pc-LEDs) were fabricated by combining CsZnCl:Cr with a green LED chip. The night-vision camera captured the distribution of blood vessels and bones in the fingers, demonstrating the promising potential of this material in the field of NIR imaging.

中文翻译：

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Cr3+ 掺杂 Cs2ZnCl4 微晶可实现近红外发射

作为一种有前途的无铅金属卤化物，CsZnCl有潜力作为主体，通过离子掺杂实现不同颜色的各种光致发光发射。因此，研究以四面体配位方式掺杂到CsZnCl中的各种离子的光学性质具有重要意义。然而，目前对 CsZnCl 近红外（NIR）发射的研究仍然缺乏。在这项研究中，我们使用简单的水热法成功合成了 CsZnCl:Cr 晶体。 CsZnCl:Cr 的发光波长范围为 800–1300 nm，峰值位置为 915 nm，在 375 nm 激发下半峰全宽 (FWHM) 为 150 nm。通过光致发光光谱、密度泛函理论（DFT）、寿命衰减曲线、温度相关光谱和时间分辨光致发光（TRPL）的分析，我们证实了Cr离子占据的两个潜在位点的存在。此外，通过将 CsZnCl:Cr 与绿色 LED 芯片相结合，制造了近红外荧光粉转换发光二极管 (pc-LED)。夜视摄像头捕捉到了手指中血管和骨骼的分布，展示了这种材料在近红外成像领域的巨大潜力。