Facile synthesis of water-soluble ZnxCd1−xSe nanocrystals via a two-phase cation exchange method

In this paper, a facile two-phase method was developed to synthesize water-soluble ZnxCd1−xSe nanocrystals through cation exchange reaction of the pre-synthesized ZnSe nanocrystals (in organic phase) with Cd2+ (in water phase) and by adding 3-mercaptopropinonic acid (MPA). High-quality alloy nanocrystals with desired emission wavelengths (ranging from 412 to 570 nm) can be synthesized precisely and reproducibly by varying the reaction temperature and time. For the first time, this new strategy allows the simultaneous execution of ZnxCd1−xSe formation and MPA functionalization. It overcomes the poor crystalline shortcomings in the water-phase synthesis. The obtained alloy nanocrystals not only have high quantum yields (QYs) and stability, but also have good crystallinity. It is expected that the reported simple synthetic strategy can be developed into a very practical approach to produce high-quality water-soluble nanocrystals.

► A two-phase cation exchange method was developed to prepare aqueous ZnxCd1−xSe nanocrystals.
► The new method allows ZnxCd1−xSe formation and MPA functionalization simultaneously.
► The obtained ZnxCd1−xSe nanocrystals have good crystallinity and stability.
► The mechanism involved in the formation of ZnxCd1−xSe nanocrystals has been studied.