Transformation Pathways in Colloidal CdTeSe Magic‐Size Clusters

A rarely studied transformation in colloidal ternary magic‐size clusters (MSCs) is addressed. We report the first observation of the transformation from ternary CdTeSe MSC‐399 to MSC‐422, which occurs at room temperature. These two MSC types display sharp optical absorption resonances at 399 and 422 nm, respectively, and are related in that they are quasi isomers, together with their counterpart precursor compounds (PCs). Binary CdTe and CdSe samples were prepared in the prenucleation stage also called the induction period (IP). After they were mixed and placed in a mixture of toluene and octylamine, the transformation was found to take place and to be assisted by the addition of the CdSe IP sample. A binary IP sample contains corresponding binary PCs and monomers (Mo) and fragments (Fr). We argue that the transformation pathway is enabled by the corresponding ternary PCs, involving the substitution reaction, namely CdTeSe PC‐399 + CdSe (Mo/Fr)‐1 ⇒ CdTeSe PC‐422 + CdSe (Mo/Fr)‐2. The present study provides an in‐depth understanding of the formation characteristics of the MSCs. A new type of ternary magic‐size cluster (MSC), CdTeSe MSC‐422 evolved at room temperature while CdTeSe MSC‐399 decreased in a mixture of toluene (Tol) and octylamine (OTA). The transformation goes through corresponding precursor compounds (PCs), with step 1 transforming PC‐399 to PC‐422, which is rate‐determining and features first‐order reaction kinetics.