Abstract:Magic-size nanocrystals (MSNCs) have recently attracted much attention because they are more stable compared to their similar-sized counterparts called regular nanocrystals (RNCs) due to their defined molecular structures.However,the synthesis of MSNCs in pure form has been acknowledged to be challenging since the coexistence of different types of MSNCs and RNCs is difficult to avoid.In the present study,CdTe MSNCs were prepared from cadmium-acetate/carboxylic acid and tri-n-octylphosphine telluride in non-coordinating solvent 1-octadecene.It was generally found that only with small amounts of carboxylic acid it was possible to obtain MSNCs of high purity.Furthermore,two different types of CdTe MSNCs were synthesized by simply varying the reaction temperature.TEM,HRTEM,XRD,EDX and XPS were used to examine the morphology,composition and crystal structure of the as-prepared CdTe MSNCs which exhibit a dot-like morphology,a wurtzite structure and a Cd-rich surface composition.Additional experiments were performed to study the growth mechanism of MSNCs using UV-vis absorption real-time monitoring.The results suggested that larger MSNCs growth at the expense of smaller ones partly dissolving into monomer which serve as growth material similar to Ostwald ripening commonly observed for RNCs.