The activity of Zn precursors determines the cation exchange reaction kinetics with Ag_(2)S:Zn-doped Ag_(2)S or Ag_(2)S@ZnS QDs

Cation exchange(CE)has been emerged as a promising post-synthesis strategy of colloidal nanocrystals.However,it is unclear how the cation precursor affects the CE process and the final colloidal nanocrystals.Herein,we utilized two Zn-B Lewis acidbase adduct complexes(B=oleylamine(OAM)and methanol(MeOH))as Zn precursors for CE with Ag_(2)S quantum dots(QDs).Our study revealed that the steric hindrance and complexing capabilities of Zn precursor significantly affect the CE kinetics.As a result,the Zn-doped Ag_(2)S(Zn:Ag_(2)S)and Ag_(2)S@ZnS core–shell QDs were successfully obtained with enormous enhancement of their photoluminescence(PL)intensities.Theoretical simulation showed that the Zn-OAM with higher desolvation energy and spatial hindrance tended to form doped Zn:Ag_(2)S QDs due to the inefficient cation exchange.Whereas the Zn-MeOH with lower exchange barrier promoted the conversion of Ag-S to Zn-S,thus forming Ag_(2)S@ZnS core–shell QDs.We anticipate that this finding will enrich the regulatory approaches of post-synthesis of colloidal nanocrystals with desirable properties.