Controlling Ion-Exchange Balance and Morphology in Cation Exchange from Cu3–xP Nanoplatelets into InP Crystals

Abstract

Synthesis of colloidal nanocrystals (NCs), which are not readily available via the wet-chemical approach based on arrested precipitation, has often relied on templated growth. Cation exchange, in which guest cations in bulk solution replace host cations in template NCs, has evolved as one of the most powerful examples. Despite its versatility and facileness, there are caveats because most of the cation-exchange processes presuppose the formation of crystalline defects, which are more or less uncontrolled in terms of population and locations. The defect formation is a consequence of the imbalance between extraction and incorporation of host and guest cations. Here, we demonstrate the controlling of ion-exchange balance in the Cu+-to-In3+ cation-exchange reaction of Cu3–xP nanoplatelets (NPLs), which triggers the nanoscale Kirkendall effect, a representative phenomenon of crystal defect generation, clearly shown by morphology change of NPLs. Cation-exchanged NPLs exhibit various morphologies depending on th...