Magneto-Luminescent\nTwo-Dimensional Nanosheets of\nGadolinium and Gold Nanocluster Assemblies with Surface Molecular\nFunctionalization for White Light Emission

We report the formation of photoluminescent two-dimensional\n(2D)\ncrystalline nanosheet assemblies of gadolinium ions and ligand-stabilized\ngold nanoclusters (Gd–Au NCs). Transmission electron microscopy,\nselected area electron diffraction in conjunction with atomic force\nmicroscopy, and field-emission scanning electron microscopy analyses\nsubstantiated the 2D nature of Gd–Au NC nanosheets. The optical\nand magnetic properties of the nanosheets were investigated by photoluminescence\nmeasurements and vibrating-sample magnetometry analyses. The so-formed\ncrystalline product was further utilized to generate a synchronous\ntricolor (orange, green, and blue) emission from a single excitation\nwavelength through an inorganic surface complexation reaction. The\nindependent emissions were tunable after ligand functionalization\nby acetylsalicylic acid and fluorescein on the Gd–Au NC assembly.\nInterestingly, the assembled superstructure with augmented quantum\nyield led to white light emission at λ<sub>exc</sub> ≈\n325 nm with CIE of (0.34, 0.33) and CRI value of >85 in the liquid\nphase. Furthermore, the ability to modulate the luminescence properties\nthrough the surface complexation of the 2D nanosheets of Au NCs may\nbring about new avenues toward applications in light-emitting devices,\nsensing, and biomedical imaging.