Structural and optical characteristics of ZnSe nanocrystals synthesized in the presence of a polymer capping agent

Quantum dots of ZnSe have been precipitated in the presence of polyvinyl pyrrolidine using a modified chemical bath method. Addition of the polymeric capping agent serves to limit particle growth and stabilize nanocrystals. Analysis of X-ray diffraction (XRD) measurements indicates that capped particles attain an average particle diameter of only 15 versus 34 Å for the uncapped material. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) results show nanocrystals to be single crystals encapsulated in polymeric material, while SAED patterns confirm that the cubic phase of ZnSe was obtained with this synthesis route. Observation of a blue shift in the optical absorption and luminescence data is consistent with the reported reduction in nanocrystal size below the ZnSe bulk exciton Bohr diameter of ∼90 Å.