An [Ag3(dppy)2(NO3)3] cluster polymer with narrowing fluorescence

Low-dimensional nanomaterials with lattice confinement, including those of nanoclusters (NCs), offer benefits for fluorescence narrowing. Compared to quantum dots of metal NCs, however, one-dimensional structures of such NCs challenge the single-crystal synthesis. Here, we report the synthesis of a novel [Ag3(dppy)2(NO3)3]n cluster polymer through the reduction of AgNO3 with NaBH4 in a dark environment. This cluster polymer incorporates the coordination and passivation of both diminished nitro groups (NO3) and diphenyl-2-pyridylphosphine (dppy) ligands. The weak Ag-Ag metallic bonds within this cluster polymer are governed by argentophilic interactions, with each Ag3 unit connected by a NO3 group. This cluster polymer exhibits photoluminescence with three emission bands at 308, 352, and 620 nm, aligned with the purple (308/352 nm) and red (620 nm) regions, respectively. We synthesized microfibers of this cluster polymer using reprecipitation, resulting in a fluorescence bandwidth reduction to approximately one-tenth in the microfiber samples relative to the diluted solution.