Ultra-Broad-Band-Excitable Cu(I)-Based Organometallic Halide with Near-Unity Emission for Light-Emitting Diode Applications

Low-dimensional hybrid metal halides demonstrate broad-band emission and high photoluminescence quantum yield (PLQY) acting as excellent candidates for a new generation of luminescent materials in lighting fields. However, most luminescent metal halides can only be excited by ultraviolet radiation, and the discovery of high-efficient emitters with broad-band excitation characteristics, especially upon efficient blue light irradiation, is a challenge. Herein, a zero-dimensional (0D) Cu(I)-based organometallic halide (18-crown-6)2Na2(H2O)3Cu4I6 (CNCI) was prepared with a green emission band centered at 536 nm and a near-unity PLQY (91.8%) upon excitation of 450 nm. Importantly, the ultrabroad excitation band covering a 300–500 nm range was observed in CNCI, and the luminescence mechanism has been discussed in detail. A white light-emitting diode (WLED) was fabricated with high luminous efficiency of 156 lm/W and a high color rendering index of 89.6. This work provides guidance for designing high-performance luminescent metal halides with suitable excitation characteristics and also promotes the application prospects of such materials in WLED fields.