Semiconductor Nanocrystal Engineering by Applying Thiol- and Solvent-Coordinated Cation Exchange Kinetics

Thiol- and solvent-coordinated cation exchange kinetics have been applied to engineer the composition and crystallinity of novel nanocrystals. The detailed thermodynamics and kinetics of the reactions were explored by NMR spectroscopy, time-dependent photoluminescence (PL) characterizations and theoretical simulations. The fine structure of the colloidal semiconductor nanocrystals (CSNCs) was investigated by X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). In this way, high-quality p-type Ag-doped ZnS quantum dots (QDs) and Au@ZnS hetero-nanocrystals with a cubic phase ZnS shell were synthesized successfully.The unprecedented dominant Ag ⁺ -dopant-induced fluorescence and p-type conductivity in the zinc-blende ZnS are reported.