Colloidal Synthesis of Ternary Copper Halide Nanocrystals for High-Efficiency Deep-Blue Light-Emitting Diodes with a Half-Lifetime above 100 h

Currently, the blue perovskite light-emitting diodes (PeLEDs) suffer from a compromise in lead toxicity and poor operation stability, and most previous studies have struggled to meet the crucial blue NTSC standard. In this study, electrically driven deep-blue LEDs (similar to 445 nm) based on zero-dimensional (0D) Cs(3)Cu(2)I(5 )nanocrystals (NCs) were demonstrated with the color coordinates of (0.16, 0.07) and a high external quantum efficiency of similar to 1.12%, comparable with the best-performing blue LEDs based on lead-halide perovskites. Encouraged by the remarkable stability of Cs3Cu2I5 NCs against heat and environmental oxygen/moisture, the proposed device was operated in a continuous current mode for 170 h, producing a record half-lifetime of similar to 108 h. The device stability was further verified by an aggressive thermal cycling test (300-360-300 K) and a 35-day storage test. Together with the eco-friendly features and facile colloidal synthesis technique, the 0D Cs3Cu2I5 NCs can be therefore regarded as a promising candidate for deep-blue LEDs applications.