Colloidal nanocrystals offer exciting opportunities in the field of solar cells; they can reduce fabrication costs, and show exotic and unique features such as: band gap tuning, multiple exciton generation, or Fermi level and energy band position tuning.
However, thinking of future commercialisation, there is a road block that these devices need to overcome. The best performing solar cells based on colloidal nanocrystals, as well as the new perovskite based solar cells, have lead on their composition, which is highly toxic and should be completely avoided.