Precision synthesis of a CdSe semiconductor nanocluster via cation exchange

Precision nanosynthesis is essential for atomic engineering in nanostructures and for mechanistic understanding of nanoscale reactions. However, emergent complexity in nanostructures and nanosynthesis makes precision synthesis challenging. Here, we report the precision synthesis of a semiconductor nanocluster via synergizing coordination, cluster and colloidal chemistry at the nanoscale. By using a Cu26Se13(PEt2Ph)14 cluster and a CdI2(PPr3)2 coordination complex as precise precursors in a colloidal cation-exchange reaction, an atomically precise Cd26Se17I18(PPr3)10 (CdSe) cluster is produced at near-unity yield. X-ray crystallography reveals that the child CdSe cluster inherits its icosahedral-packed anion lattice and halide-phosphine-rich surface from the parent cluster and complex, respectively. The hybridization of achiral precursors leads to chiral CdSe clusters cocrystallized as a 1:1 mixture of enantiomers. In situ optical spectroscopy is used to map the precise reaction pathways. On the basis of charge and coordination conservations, the atomic structure of the CdSe cluster can be linked to its synthetic precursors via a series of transformations including surface coordination exchange, intracluster reorganization and intercluster digestive ripening. The precision nanosynthesis described here, with atomically defined precursors, pathways and products, is expected to further facilitate the atomic engineering of functional nanostructures. By combining coordination, cluster and colloidal chemistry, precision synthesis is realized in cation-exchange reactions of nanoclusters (Cu2Se to CdSe). The precise transformation unveils the origin of chirality and polarity in semiconductor nanomaterials and enables atomic visualization of complex reaction mechanisms.