Halogen-Engineered Copper-Based Materials with Multicolor Emission for Dual-Functional Anticounterfeiting and LED...

Two novel zero-dimensional Cu-based halides (C₆H₇ClN)₄Cu₂X₆ (X = Cl, Br) with excellent emission performances were successfully synthesized by a simple solution method. The hydrogen bonds and distortions of [Cu₂X₆]^4- clusters make (C₆H₇ClN)₄Cu₂Cl₆ and (C₆H₇ClN)₄Cu₂Br₆ crystallize in monoclinic P2₁/c and triclinic P1, respectively. Interestingly, attributed to STE mechanisms, (C₆H₇ClN)₄Cu₂Cl₆ and (C₆H₇ClN)₄Cu₂Br₆ display broadband green-yellow and green emissions, large Stokes shifts, broad fwhms, and long lifetimes of the microsecond level. Notably, the PLQY was enhanced from 59.68 to 71.15% by halogen regulation with Br^- being utilized to replace Cl^-. Furthermore, first-principles calculations were performed to investigate the relationship of structure-performance. Moreover, based on the bright emissions and different emitting colors of (C₆H₇ClN)₄Cu₂Cl₆ and (C₆H₇ClN)₄Cu₂Br₆, multiple anticounterfeiting methods and LED devices in solid-state illumination were designed to explore underlying optoelectronics applications. This work not only provides two novel low-dimensional copper halides with excellent photoluminescence but also promotes practical applications in information security and solid state lighting.