Preparation and optical properties of polyethyleneimine-stabilized colloidal CdSe and CdSxSe1–x quantum dots

Using unbranched polyethyleneimine as a stabilizer, we have obtained colloidal aqueous solutions of ultrasmall (1.8-1.9 nm) CdSe particles, characterized by a narrow size distribution and photoluminescence in the visible region of the spectrum with quantum yields up to 12% and decay constants in the range 10 -1 to 10 2 ns. A similar approach was used to obtain colloids of nanoparticles of a CdS x Se 1– x solid solution with a tailored composition.