Acid‐Programmed Generation of Coordination, Ionic, and All‐In‐One Cu(I) Chloride Architectures with Highly Efficient Luminescence

Abstract Copper(I)‐based hybrid halides feature highly designable structures, systematic tunability, and excellent photoluminescence; however, developing design rules that can predictably modulate their emission across different structural types remains under explored. Here, we report an acid‐programmed generating approach, in which reaction acidity simultaneously modulates ligand protonation and the nucleation barrier, thereby generating coordination, ionic, and all‐in‐one copper(I) chloride architectures by tuning reaction acidity and affording six new compounds with emissions spanning 520–625 nm. Among these, the AIO compound 3 A‐1H[CuCl 2 ] (A = 4‐(aminomethyl)pyridine, 4AMP) exhibits a record‐high photoluminescence quantum yield (PLQY) of 99%, setting a new benchmark for AIO Cu(I)‐based emitters. Temperature‐dependent photoluminescence and time‐resolved spectroscopy reveal that the ultrahigh PLQY originates from enhanced lattice rigidity and a triplet phosphorescence pathway. Solubility and thin film fabrication demonstrate excellent processability, while long‐term stability stands in stark contrast to the notorious instability of conventional Cu(I) halides. Moreover, mixing compounds yields broad‐range white‐light emission, underscoring the potential of materials for tunable and high‐efficiency solid‐state lighting. This study establishes acid‐driven structural integration as a general strategy for constructing functional copper(I) halide compounds, laying the foundation for stable, solution‐processable, and high‐performance optoelectronic materials.