Morphology Transformation of Chalcogenide Nanoparticles Triggered by Cation Exchange Reactions

Plenty of chalcogenide families with tremendous potential for functional applications remain unexplored due to the limitations of conventional synthesis methods. However, cation exchange reactions in colloidal synthesis offer an alternative way to overcome these limitations and provide a route to synthesize pure phases and morphologies that otherwise are challenging to achieve. In this work, we demonstrate the possibility of Sb ³⁺ to undergo cation exchange reactions with Cu ⁺ in Cu _2-x Se nanoparticles and study an uncommon morphology transformation from Cu _2-x Se nanoparticles to Cu ₃ SbSe ₃ nanoplates. The morphology transformation is dictated by a growth process of assembly and merging of primary nanoparticles triggered by the incorporation of Sb cations into the Cu _2-x Se lattice and the rearrangement of the anion framework. By studying this unprecedented phenomenon in cation exchange reactions and adding Sb to the list of available elements for exchange, this work provides insight into the unexplored potential of cation exchange reactions and opens the possibility to synthesize complex Cu-based chalcogenide materials.