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 (C4 H10 N)4 Cu4 I8 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, (C4 H10 N)4 Cu4 I8 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 (C4 H10 N)4 Cu4 I8 originates from the electron interactions in [Cu2 I4 ]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 (C4 H10 N)4 Cu4 I8 SCs, which present the promising applications of low-dimensional cuprous-based halides in solid-state lighting.