Optical properties of CdSe and CdSe/ZnS quantum dots dispersed in solvents of different polarity

Original organic capping TOPO/TOP groups of CdSe and CdSe/ZnS quantum dots (QDs), from mother solution were replaced with 2_mercaptoethanol, which was chosen as model compound, in order to achieve water solubility. Obtained water dispersions of CdSe and CdSe/ZnS QDs were characterized by UV/VIS absorption and luminescence techniques. Luminescence measurements revealed that bare cores are very sensitive to surface capping, transfer into water diminished emission intensity. Core/shell, CdSe/ZnS, QDs are much more resistant to changes of the capping and solvent, and significant part of emission intensity was preserved in water.