Cation/Anion Exchange Reactions toward the Syntheses of Upgraded Nanostructures: Principles and Applications

The last 5 years have witnessed rapid progress in the field of hybrid nanostructures toward enhanced optical and electronic properties. On this topic, we focus on the relevant progress that has been achieved on the basis of cation/anion exchange reactions (CERs/AERs). Different from those direct synthesis strategies, CERs/AERs can offer more freedom in tuning the chemical composition, crystal phases, doping, interfaces, and morphologies, which are key parameters to determine the optical and electronic properties of the target products. We present several examples, e.g., doped quantum dots (QDs), engineered core-shell QDs, metal-semiconductor hybrid nanostructures, hollow structures, and inorganic perovskite nanocrystals. These upgraded structures afforded by CERs/AERs generally exhibit improved properties, such as increased quantum yields, prolonged lifetimes, and well-engineered band gaps for charge transportation and recombination, thus providing more opportunities for further advanced applications.