From Magic Size to Atomic Precision: Facile Synthesis of a CdTe Semiconductor Nanocluster
Saryvoudh A. Mech, Joshua O. Gibson, Fuyan Ma, Łukasz Dobrzycki, Chenjie Zeng
Abstract
Facile synthesis of atomically precise semiconductor nanoclusters remains an important challenge, especially for those with heavier chalcogens. Combining coordination and colloidal methods, we developed a simple approach for synthesizing an atomically precise CdTe nanocluster with high purity and stability. Specifically, a precise cadmium–thiolate compound, [Cd 4 (SR) 9 ] n, was reacted with a facile phosphine telluride (TePR 3 ) precursor to produce a CdTe magic-sized cluster with a distinct absorption peak at 377 nm and a narrow linewidth of 20 nm. X-ray crystallography reveals the cluster is Cd 32 Te 14 (SR) 36 (PR 3 ) 4, a homologue of Cd 32 S 14 and Cd 32 Se 14 reported about three decades ago, thus filling the missing link in this family. The cluster features a zincblende core in a truncated tetrahedron shape. While the core is achiral, chirality emerges from the rotational stacking of surface ligands. The left and right enantiomers self-assemble into a highly ordered, atomically coherent cubic superlattice, leading to a rare racemic crystal coined as “kryptoracemate.” This method provides an accessible platform for further atomic engineering of CdTe and related nanoclusters toward their target applications.