Near‐Infrared and Cyan Dual‐Band Emission Copper Iodide Based Halides with [Cu6I9]3− Cluster.

The luminescence property of various compounds is developed in the photoelectric applications field, while the near‐infrared (NIR) dual‐band emission of compounds is extremely challenging. Herein, 0D Cu(I)‐based organic–inorganic module (ETA)3Cu6I9 is synthesized to achieve NIR and cyan dual‐band emission in metal halide systems. Density functional theory (DFT) calculations combined with comprehensive spectroscopic data reveal its emission mechanism. Under the excitation at 371 nm, (ETA)3Cu6I9 shows the broadband NIR emission peaking at 775 nm with a large wavelength, attributed to the triple‐cluster‐center (3CC) transition. Meanwhile, under 286 nm excitation, (ETA)3Cu6I9 shows a bright cyan emission peaking at 490 nm, attributed to the metal‐to‐ligand charge transfer (MLCT) or halide‐to‐ligand charge transfer (XLCT) transitions. Moreover, (ETA)3Cu6I9 presents relatively superior thermal and air stability. Benefiting from the good stability of (ETA)3Cu6I9, the as‐fabricated NIR‐LED device demonstrates great potential in biological imaging and night vision. This study opens up a new way for designing new non‐toxic NIR and cyan dual‐band emission materials, which guides to synthesize new materials in metal halide field. [ABSTRACT FROM AUTHOR]