Magic‐Sized Stoichiometric II–VI Nanoclusters

Abstract

Metal chalcogenide nanomaterials have gained widespread interest in the past two decades for their potential optoelectronic, energy, and catalytic applications. The colloidal growth of various forms of these materials, such as nanowires, platelets, and lamellar assemblies, proceeds through certain thermodynamically stable, ultrasmall (<2 nm) intermediates called magic‐sized nanoclusters (MSCs). Due to quantum confinement and its resultant intriguing properties, isolation or direct synthesis of MSCs and their structure characterization, which is very much challenging, are current topics of fundamental and applied scientific research. By comprehensive understanding of the structure–activity relationships in MSCs, the nucleation and growth processes can be manipulated, resulting in the synthesis of novel metal chalcogenide materials for various applications. This review focuses on recent advances in the chemical synthesis, characterization, and theoretical calculations of CdSe and its related II–VI nanoclusters. It highlights the studies of photophysical and magneto‐optical properties as well as heteroatom doping of MSCs followed by their chemical transformation to high‐dimensional nanostructures. At the end of the review, future directions and possible ways to overcome the challenges in the research of semiconductor MSCs are also presented.

Spontaneous alloying of ultrasmall non-stoichiometric Ag–In–S and Cu–In–S quantum dots in aqueous colloidal solutions

“…The magic-size clusters intermediary between molecular and solid-state of metal chalcogenide semiconductors are currently recognized as ever-present precursors for the formation of many binary II-VI and IV-VI compounds, 13,14 but such species are still to be discovered and studied for ternary metal-chalcogenide semiconductors, like CIS or AIS. The thermally activated redistribution between such magic-size clusters and QDs, from one side, and molecular species, from the other side, can be strongly facilitated by the presence of multifunctional GSH, which can form covalent bonds with the QD surface, coordination bonds with metal cations, ionic bonds with chalcogenide anions, and serve as a universal "shuttle" among CIS and AIS QD and clusters during the spontaneous alloying.…”

To inorganic nanoparticles via nanoclusters: Nonclassical nucleation and growth pathway

“…Nucleation occurs in three different scenarios: classical nucleation, spinodal decomposition, and nonclassical nucleation (Figure 4). 3,16 In the classical nucleation theory, large surface‐to‐volume ratios of the nuclei cause high thermodynamic energy barriers, which form a hurdle to homogeneous nucleation. The thermodynamics of homogeneous nucleation, in terms of the competition between surface energy and bulk free energy, can be expressed as a function of nuclear radius (Equation 2).…”

Magic-sized CdSe nanoclusters: a review on synthesis, properties and white light potential

“…The absorbance of the two peaks having shorter wavelengths is weaker because of the secondary and tertiary electronic transitions of MSNC-415. Recently, Bootharaju et al 103 have also published a review article on II-VI nanoclusters. The challenges faced during synthesis and techniques used for characterization of such MSNCs were very well highlighted.…”