Executive Summary : | MHP nanocrystals (NCs) with a size of 1-10 nm have become a popular semiconductor material in optoelectronics due to their excellent light harvesting and emitting properties. Current research focuses on shape-controlled synthesis and ligand engineering, with researchers asserting that the optoelectronic performance and colloidal stability of MHP NCs are heavily reliant on their surface chemistry, particularly the shape of the NCs and the choice of capping ligands. Facet modulations of MHP NCs are essential for controlling the surface energetic, which dictates their performance as photocatalysts in various redox reactions, particularly CO2 reduction. However, there are no investigations devoted to exploring the underlying reasons for this activity. Fundamental gaps in literature include understanding how undercoordinated sites contribute to surface energetics and energy level alignment, how electron and holes can be intrinsically localized in different facets by modulating the shape of NCs, and how the extent of uncoordinated sites plays a role in the energy level of electronic states.
The proposal aims to fill these gaps using first-principles based computational modelling using nanocluster models with cutting edge computational techniques. The specific objectives are to obtain trap-free NCs with different shapes and study their surface energetics with respect to the extent of undercoordinated sites. The size of NCs and the role of capping ligands will be thoroughly investigated, with an emphasis on finding a deeper structure-property understanding of MHP NCs as photocatalysts and optoelectronics. |