Ultra-Broad-Band-Excitable Cu-Based Halide (C 4 H 10 N) 4 Cu 4 I 8 with High Stability for LED Applications.

Currently, organic-inorganic hybrid cuprous-based halides are receiving substantial attention for their eco-friendliness, distinctive structures, and outstanding photophysical properties. Nevertheless, most of the reported cuprous-based halides demand deep ultraviolet excitation with a narrow excitation range that can meet the commercial requirement. Herein, zero-dimensional (0D) cuprous-based halide (C 4 H 10 N) 4 Cu 4 I 8 single crystals (SCs) were synthesized, with an ultrabroad band excitation ranging 260-450 nm and a greenish-yellow emission band peaking at 560 nm. Excitingly, (C 4 H 10 N) 4 Cu 4 I 8 also features a large Stokes shift of 300 nm, a high photoluminescence quantum yield (PLQY) of up to 84.66%, and a long lifetime of 137 μs. Furthermore, density functional theory calculations were performed to explore the relationship between structure and photophysical properties, and the photoluminescence performance of (C 4 H 10 N) 4 Cu 4 I 8 originates from the electron interactions in [Cu 2 I 4 ] 2- clusters. Taking advantage of broad band excitation and excellent photoluminescent performances, a high luminescence characteristic UV-pumped light-emitting diode (LED) device with remarkable color stability was fabricated by employing the as-synthesized (C 4 H 10 N) 4 Cu 4 I 8 SCs, which present the promising applications of low-dimensional cuprous-based halides in solid-state lighting.