Our research focuses on the electronic, chemical and optical properties of semiconductor nanostructures (quantum dots) and hybrid nanoscale materials prepared by means of colloidal syntheses. Such nanoparticles can be chemically manipulated like large molecules and can be coupled to each other or can be incorporated into different types of inorganic or organic matrices.
  
 
 

   


 
 
    Transmission electron microscope images of (ZnSe/CdS)/CdS hetero-NRs fabricated using low (a-d) and high (e-h) concentrations of precursors.
  
 

  
    Type II carrier localization in ZnSe/CdS nanorods and ZnSe/CdS/ZnSe nano-barbells. An offset of band edges at the interface of ZnSe and CdS materials promotes spatial separation of an excited electron-hole pair into opposite parts of the structure (type II carrier confinement), as a result an electron wave function becomes primarily
  
 
localized within CdS and a hole within ZnSe semiconductor materials. The subsequent recombination of spatially-separated excitons occurs across the ZnSe/CdS interface, which leads to a considerable red-shift of the emission peak in ZnSe/CdS nanorods, with respect to the band edge emission in ZnSe (420 nm) and CdS (440 nm) NCs.
  
 
 

    Direct attachment of specific-sized quantum dots (QDs) onto mesoporous TiO2 is required for efficient photoelectrons transfer. Epitaxially grown colloidal PbSe on TiO2 nanorods were obtained using standard Schlenk technique. The TEM images of PbSe/TiO2 heteronanocrystals are shown in Figure. The short fluorescent life time of 2.1 ns attests the fast photoelectron injection from QDs into the TiO2 nanorods. This heterostructure without the presence of organic linker could lead improved light conversion efficiency.
    (a) Schematic of the PbSe/TiO2 synthesis. (b-e) PbSe/TiO2 HNCs that form after the initial (b,c) and the secondary (d, e) injections of Pb and Se precursors. (a) Schematic of the PbSe/TiO2 synthesis. (b-e) PbSe/TiO2 HNCs that form after.
  
Designed by July-2009