Single Source Polychromatic Luminescent and White Emitting Copper Nanoclusters

Abstract The low cost and fine‐tunability of the luminescence of copper nanoclusters make them attractive candidates for opto‐electronic, imaging, and sensing applications; their stability, and a precise understanding of the structure–function correlations however, continue to be challenging. A comprehensive chemical etching strategy is developed to synthesize orange, blue, and cyan emitting nanoclusters from a single source of ultrasmall copper nanoparticles; high quantum yields up to ≈34% are realized. Steady state and time‐resolved spectroscopy, electron microscopy, high resolution mass spectrometry, and computational modeling provide critical mechanistic insight into the polychromatic luminescence. A facile method for the fabrication of polymer nanocomposite thin films that sustain and stabilize the luminescent nanoclusters is presented. A subtle variation of the etching strategy without the need to admix multiple components, provides white luminescent thin films with Commission Internationale de l'éclairage (CIE) coordinates, x = 0.35, y = 0.33. The highlights of this work are i) the simple solution synthesis of stable, uniform, and pure ultrasmall Cu nanoparticles, ii) their chemical etching by subtle variations in an optimized protocol to produce highly luminescent, polychromatic nanoclusters, including white‐emitting ones, iii) stabilization of the bright luminescent systems in nanocomposite thin films, and iv) a detailed analysis of the luminescence tuning.