Kui Yu1
Sichuan University1
The synthesis of photoluminescent (PL) colloidal semiconductor quantum dots (QDs) has been performed as an empirical art, while colloidal semiconductor magic-sized clusters (MSCs) are reported as a side product. Their growth relation has been addressed only in a limited fashion, with different opinions expressed in the literature. It is critical to develop fundamental understanding, especially regarding the pre-nucleation stage also called the induction period (IP). Here, I will talk about chemical reactions including the effect of the impurity in tri-<i>n</i>-octylphosphine (TOP) in Part 1 and the nucleation pathway with the proposed two-pathway model (Yu) in Part 2. For the latter, we suggest that there are two individual pathways in the prenucleation stage of QDs. The self-assembly of metal (M) and chalcogenide (E) precursors followed by the formation of binary II-VI ME MSCs inside each assemble depicts Pathway 1. The LaMer model of the classical nucleation theory (CNT) describes Pathway 2. The two pathways are inter-connected via a special intermediate, called the precursor compound (PC) of MSCs. I will introduce our latest advances on the PC-enabled pathway (with monomer substitution or addition) for transformations among various MSCs, as well as on the PC-enabled synthesis of various nano-species. Hopefully, this presentation brings a deeper understanding into the prenucleation stage of QDs. We believe that the synthesis of colloidal nanocrystals is slowly and quietly transforming from an empirical art to science.<br/><br/><b>References</b><br/>1. Yu, K. et al Effect of tertiary and secondary phosphines on low-temperature formation of quantum dots. <i>Angew. Chem. Int. Ed.</i> <b>2013</b>, <i>52</i>, 4823–4828.<br/>2. Yu, K. et al A Two-pathway model for the evolution of colloidal compound semiconductor quantum dots and magic-size clusters. <i>Adv. Mater. </i><b>2022,</b> <i>34</i>, e2107940.