Research Projects

Ternary chalcogenides (M-M'-Q) are low-bandgap materials with potential applications in electronics, photovoltaics, electrochemical capacitors, and batteries. Due to the multiple oxidation states of transition metals, M-M'-Q can be formed with various compositions, affecting their structure and electronic properties. The solution phase synthesis of M-M'-Q has been exciting for its size-dependent optoelectronic properties. M-M'-Q is composed of transition metals (M and M'), which have different reactivities, making it difficult to form directly. The TCNC can only form due to cation exchange between M and M'. In homovalent cation exchange, M and M' have the same oxidation state, and M' replaces the same numbers of M to form the final M-M'-Q composition. In contrast, aliovalent cation exchange is more complex as M' replaces non-equivalent numbers of M. Researchers have reported that the crystal structure and composition of M-Q binary chalcogenides nanocrystals may vary with passivating ligands and precursors used in the reaction. However, no understanding of the growth mechanism exists in the literature. This proposed work aims to develop a mechanistic picture of the growth mechanism of cation exchanges to synthesize TCNCs. Initial studies suggest that the growth mechanism depends strongly on the initial crystal structure of the BCNCs of M-Q. The main experiments will study the growth mechanism of Cu-M5-Q and Cu-M15-Q TCNCs with different reactive Q precursors in hot-injection and one-pot synthesis. The outcomes of these studies can be extended to the development of heterostructures in TCNCs and TDMCs.