Energy transfer in solution-based complexes of CdTe nanocrystals electrostatically bound by calcium ions

Colloidal semiconductor nanocrystals with controllable surface properties are attractive objects for use as building blocks in different functional structures within the bottom-up assembly approach. We produced stable complexes from differently-sized water soluble CdTe nanocrystals capped by mercaptoacid stabilizers through electrostatic interactions of negatively charged carboxylic groups of capping ligands with positively charged Ca(II) cations. Energy transfer between smaller nanocrystals (donors) and larger nanocrystals (acceptors) in fabricated complexes is demonstrated by means of steady-state and time-resolved photoluminescence spectroscopy, paving the way to nanocrystal-based light harvesting structures