Nanohybrid systems consisting of semiconductor quantum dots and closely associated or covalently bound organic chromophores can exhibit exciting phenomena—such as Förster-type energy transfer—which have proved useful for expanding the color range in emissive displays and improving the efficiency of dye-sensitized solar cells. However, the heterogeneity of these materials, which originates from polydispersity in quantum dot size/shape and variable chromophore orientation, makes establishing relationships between structure and photophysical properties difficult. Atomically precise nanoclusters allow the absolute structure of nanocrystalline systems to be determined by X-ray crystallography, thereby relieving the issue of nanocrystal heterogeneity and providing a platform to establish robust structure-property relationships. Despite these advances, using atomically precise systems to investigate photophysical interactions between inorganic clusters and organic complexes has remained relatively underexplored. Here, we report the synthesis, structure, and optical properties of a series of nanohybrid cocrystals comprised of [Ag56S(μ6-S)12(StBu)20(EtOCS2)12]2- clusters and precisely oriented triazatriangulenium chromophores. Steady-state and time-resolved spectroscopic characterization reveal energy transfer (&lt; 10 ns) from the photo-excited cluster to the chromophore, thereby limiting non-radiative decay of the longer-lived cluster emission (~35 ns) and providing a potential pathway for enhanced quantum yield. Leveraging the synthetic tunability of triazatriangulenium chromophores, we tune their inter-chromophore distance within the superlattice to enable exciton coupling and split the fluorescence into multiple emission energies. We then correlate the cocrystals’ emission energies and lifetimes to their X-ray crystal structures and build atomically precise relationships—corroborated by time-dependent density functional theory calculations—between these properties and the specific arrangement of components within the hybrid superlattice. In addition, we demonstrate how single-atom manipulation of the cluster’s central atom affects its emission and chromophore coupling in nanohybrid assemblies. These results emphasize how the predictable synthetic control and crystallographic structure determination of atomically precise systems can enable robust structure-property relationships and enhance our understanding of photophysical properties in nanohybrid materials.

Establishing structure-property relationships in atomically precise Ag-S cluster-chromophore systems

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.