Co-assemblies of Silver Nanoclusters and Fullerenols With Enhanced Third-Order Nonlinear Optical Response

Exploring potential third-order nonlinear optical (NLO) materials attracts ever-increasing attention. Given that the atomically precise and rich adjustable structural features of silver nanoclusters (Ag NCs), as well as the unique π-electron conjugated system of carbon-based nanomaterials, a supramolecular co-assembly amplification strategy to enhance the luminescent intensity and NLO performance of the hybrids of the two components, are constructed and the relationship between structures and optical properties are investigated. By combining water soluble Ag NCs [(NH₄)₆[Ag₆(mna)₆] (H₂mna = 2-mercaptonicotinic acid, abbreviated to Ag₆─NCs hereafter) containing uncoordinated carboxyl groups with water-soluble fullerene derivatives modified with multiple hydroxyl groups (fullerenols, C₆₀─OH), the π-electron delocalization is expanded owing to non-covalent hydrogen bonding effect between Ag6─NCs and C₆₀─OH, which provides a feasible basis for realizing the NLO response. Then, the co-assemblies are doped into a PMMA matrix to prepare composite film and its NLO properties are evaluated by Z-scan technique. Remarkably, the effective nonlinear absorption coefficients β is of two orders magnitude higher than those of the Ag₆─NCs assemblies at the absence of C₆₀─OH. This work showcases a new approach for amplifying NLO responses which greatly facilitates the development of integrated photonic devices.