Dual-ligand engineering for single-component white-light generation: new opportunities in copper nanoclusters

Achieving single-component white-light emission from atomically precise metal nanoclusters remains a challenge, as most reported systems rely on unstable self-assembly or mixed-species ensembles. Here, we introduce a dual-ligand-engineered, pH-guided structural reconstruction strategy that enables the formation of a compositionally defined copper nanocluster capable of near-ideal white-light emission. Using bromelain and glutathione as co-stabilizing ligands, pH-modulated synthesis yields distinct blue, green, and red-emitting intermediates that undergo sequential reconstruction to form the final single-emissive species, (Bro)₂(GSH)₄Cu₈, as established by MALDI-TOF mass spectrometry. These nanoclusters exhibit white-light emission with CIE coordinates of (0.33, 0.35), a color rendering index of 96, and a correlated color temperature of 6082 K. Encapsulation in agarose enhances the quantum yield from 10.4% to 19.3% and preserves emission stability under continuous excitation, demonstrating compatibility with solid-state environments. These findings provide a ligand-directed route for controlling nanocluster nuclearity and emission, enabling the development of single-component nanocluster phosphors for lighting applications.