Colloidal Zn ₃ X ₂ (X = P, As) quantum dots with metal salts and their transformation into (In _y Zn _{1− y} ) ₃ X ₂ via cation-exchange reactions

We synthesized uniform Zn₃X₂ (X = P, As) quantum dots (QDs) for the first time using a stable, environmentally friendly zinc precursor instead of an organometallic precursor such as Me₂Zn or Et₂Zn, and controlled the QD size from about 2.0 nm to 6.0 nm. Moreover, tetragonal Zn₃P₂ and Zn₃As₂ QDs were transformed into zinc blende (In_yZn_1-y)₃P₂ and (In_yZn_1-y)₃As₂ QDs via the In³⁺ cationic-exchange reaction. To ensure the cation exchange reaction, we controlled reaction conditions, and confirmed it with various analytical methods. The replacement of Zn²⁺ by In³⁺ in the Zn₃X₂ QDs did not lead to changes in the particle size, but altered the optical properties and structure. In addition, we presented Cd₃P₂ and Cd₃As₂, which have the same tetragonal structure as the Zn₃X₂ QDs, through the same cationic exchange reaction.