Cu Vacancies Boost Cation Exchange Reactions in Copper Selenide Nanocrystals

摘要: We have investigated cation exchange reactions in copper selenide nanocrystals using two different divalent ions as guest cations (Zn2+ and Cd2+) comparing the reactivity of close to stoichiometric (that is, Cu2Se) with that nonstoichiometric (Cu2–xSe) nanocrystals, gain insights into mechanism at nanoscale. found presence a large density vacancies significantly accelerated process room temperature corroborated vacancy diffusion one main drivers these reactions. Partially exchanged samples exhibited Janus-like heterostructures made immiscible domains sharing epitaxial interfaces. No alloy or core–shell structures were observed. The role phosphines, like tri-n-octylphosphine, reactions, is multifaceted: besides acting selective solvating ligands for Cu+ exiting nanoparticles during exchange, they also enable anion diffusion, by extracting an appreciable amount selen...