One-pot synthesis of Cs3Cu2I5 nanocrystals based on thermodynamic equilibrium

Abstract

Copper halide Cs₃Cu₂X₅ (X = Cl, Br, I) nanocrystals (NCs) have become a research hotspot in recent years. Compared with perovskite NCs, they have a large Stokes shift with a self-absorption-free effect and convenient solution processability, which endows them with potential applications in high-resolution flexible X-ray imaging and ultraviolet detection. However, the synthesis of Cs₃Cu₂I₅ NCs is limited to the hot-injection method, which needs tedious operation procedures. Here, a one-pot fabrication strategy was designed based on the principle of chemical potential and thermodynamic equilibrium to achieve the mass production of Cs₃Cu₂I₅ NCs. With the assistance of I⁻, Cs₃Cu₂I₅ NCs were successfully fabricated with a reaction yield of about 70%, with the emission peak located at 445 nm and a high photoluminescence quantum yield (PLQY) of 72.6%. By scaling up the initial reaction volume tenfold, we successfully demonstrated mass production. Furthermore, Cs₃Cu₂Br₅ and Cs₃Cu₂Cl₅ NCs were also fabricated using this approach, indicating the versatility of this method. This strategy effectively optimizes the experimental process and cost, providing convenience for subsequent research based on this kind of material, such as optical electronic devices, ion-doping studies and so on.