Tailoring Förster Resonance Energy Transfer in Copper Nanoclusters‐Polymer Nanoparticles Composites through Ligands.

Atomically precise metal nanoclusters (MNCs) represent an emerging class of nanomaterials for light harvesting materials. Here, we synthesized Cu₉ nanoclusters (NCs) with cysteine (CYS) and reduced glutathione (GSH) ligands, along with poly(N‐vinyl carbazole) (PVK) nanoparticles (PNPs). Nanocomposites of Cu₉ NCs with PVK PNPs via electrostatic attachment have been designed to investigate their energy transfer process. A significant overlap of their absorption spectra with the emission of PVK and the absorption band of Cu NCs facilitated the Förster resonance energy transfer (FRET) from PVK PNPs to the Cu NCs. Steady‐state and time‐resolved spectroscopic studies confirm the FRET dynamics, and parameters, such as energy transfer efficiency, donor‐acceptor distance, rate constants, and the antennae effect were calculated. Our results revealed that Cu CYS/PVK PNP nanocomposite exhibited a higher energy transfer efficiency (77 %), faster energy transfer rate, and higher antennae effect than the Cu GSH/PVK PNP system. This was attributed to the shorter donor‐acceptor distance in the Cu CYS/PVK PNP system. The larger GSH ligand caused steric hindrance, reducing dipole‐dipole interactions and diminishing the FRET efficiency in the Cu GSH/PVK PNP system. These findings demonstrate the role of ligands in modulating FRET performance and designing high‐efficiency MNCs‐based light‐harvesting systems. [ABSTRACT FROM AUTHOR]