New Strategies and Synthetic Routes to Synthesize Fluorescent Atomic Quantum Clusters
Atomic quantum clusters (AQCs) of metals typically consist of several to tens of atoms, with sizes below 2 nm, comparable to the Fermi wavelength of electrons. Due to electron confinement and discrete energy levels, these clusters display “molecule-like” properties different from the corresponding bulk/nanoparticle materials. They possess high fluorescent efficiency, excellent photostability, particularly small size, and especially lower toxicity than quantum dots (QDs). Recent advances in synthetic methodologies allow metal quantum clusters protected with different ligands and scaffolds with tunable sizes and emission colors covering the visible spectrum to be obtained. Therefore, they appear to be promising fluorescent materials with a multitude of potential applications, especially in the life sciences.