Near‐Unity Green Luminescent and Stable Lead‐Free Cs₃Cu₂Cl₅ Nanocrystals Assisted by MnC₂O₄ Treatment

Abstract

The toxicity and chemical instability shortcomings of lead halide perovskites are major concerns that continue to motivate the search for next generation alternatives. Copper halides are known to be lead‐free, earth‐abundant, low‐cost, and environmentally friendly, and affordable in optoelectronic performance due to their bright luminescence, tunable emission wavelength, and excellent stability. However, the controlled synthesis of low‐dimensional copper halide nanocrystals (NCs) with near‐unity photoluminescence quantum yield (PLQY) and high stability remains a great challenge. In this work, we report a reasonable optimization approach for the preparation of Cs3Cu2Cl5 NCs by hot‐injection colloidal synthesis technology. Specifically, the Cs3Cu2Cl5 NCs synthesized with MnC2O4 as the defect repair agent exhibited negligible self‐absorption, bright green luminosity with PL emission at about 535 nm and PLQY can be increased from 68.7% to 100%. The Cs3Cu2Cl5 NCs shows excellent stability and outstanding optical properties, and is expected to be used as highly efficient green light emitter in high‐efficiency X‐ray scintillator.