Europium Doped Atomically Precise Bismuth Oxido Nanoclusters as Molecular Building Blocks for Photoluminescent Hybrid Materials

Structural and optical characterization of Eu$^{3+}$ doped atomically precise bismuth oxido nanoclusters (BiO-NCs) of about 2 nm in size is reported. The BiO-NC [Bi$_{38}$O$_{45}$(NO$_3$) 24 (dmso) 28 ]:Eu (C-1D :Eu) is transformed into soluble methacrylate ($^−$OMc) coordinated [Bi$_{38}$O$_{45}$(OMc)$_{24}$(dmso)$_4$]:Eu⋅4dmso⋅4H$_2$O (C-2$_D$:Eu) and [Bi$_{38}$O$_{45}$(OMc)$_{24}$(EtOH)$_{10}$]:Eu⋅4EtOH (C-2$_E$:Eu) by ligand exchange and without changing the amount of Eu$^{3+}$ doping (ω ≈ 1%). Based on SC XRD analysis of C-1$_D$:Eu and C-2$_E$:Eu partial substitution of the bismuth atoms with preference in the inner {Bi$_6$O$_9$} core of the {Bi$_{38}$O$_{45}$} cluster is suggested. Temperature dependent photoluminescence studies show bismuth- and europium-based dual emission at low temperatures, whereas only the latter is preserved at room temperature....