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Keywords:

  • core–shell structure;
  • magic-size seeds;
  • nanotechnology;
  • one-pot synthesis;
  • quantum dots

Abstract

The principal methods for the synthesis of highly luminescent core–shell colloidal quantum dots (QDs) of the most widely used CdSe, CdS, ZnSe, and other AIIBVI nanocrystals are reviewed. One-pot versus multistage core synthesis approaches are discussed. The noninjection one-pot method ensures slow, controllable growth of core nanocrystals starting from magic-size seed recrystallization, which yields defect-free cores with strictly specified sizes and shapes and a high monodispersity. Subsequent injection of shell precursors allows the formation of gradient core–shell QDs with a smooth potential barrier for electrons and holes, without strains or interfacial defects, and, as a consequence, a luminescence quantum yield (QY) approaching 100 %. These general approaches can also be applied to semiconductor core–shell QDs other than AIIBVI ones to cover the broad spectral range from the near-UV to IR regions of the optical spectrum, thus displacing fluorescent organic dyes from their application areas.