Ripening of two-dimensional colloidal CdSe nanocrystals into zero-dimensional nanodots

Understanding the ripening of two-dimensional (2D) colloidal nanocrystals (NCs) is important for the controllable synthesis of NCs with desired morphology and properties. In this study, we systematically investigate the ripening behavior of the 2D CdSe NCs in the presence of a short-chain acetate ligand and a long-chain oleate ligand. We find that a low acetate/oleate ratio, a low Cd/Se ratio, and a low monomer concentration help in the ripening of the 2D NCs to form 0D NCs. Moreover, a porous nanosheet intermediate is observed when there is a high Cd/Se ratio, whereas in the case of a low Cd/Se ratio, the ripening starts from the edge of the nanosheets, resulting in a saw-like nanosheet intermediate. These findings provide necessary insights into the growth and ripening of 2D CdSe NCs that allow for the controlled synthesis of 0D and 2D CdSe NCs.

Automated summary

This study systematically investigates the ripening behavior of 2D CdSe NCs and finds that a low acetate/oleate ratio, low Cd/Se ratio, and low monomer concentration facilitate the formation of 0D NCs. The presence of a high Cd/Se ratio leads to a porous nanosheet intermediate, while a low Cd/Se ratio results in a saw-like nanosheet intermediate during ripening. These insights are crucial for controlled synthesis of 0D and 2D CdSe NCs.