Surface chemistry of semiconductor nanocrystals

The fluorescence properties of CdSe semiconductor nanocrystals are investigated after surface modification with different kinds of molecular ligands. We show that the fluorescence is decreasing after removal of the excess ligands because the ligands are usually not strongly bound to the surface. The ligand exchange by multi-functional dye labelled polymer ligands allows to investigate the nanocrystal-ligand interaction by fluorescence resonance energy transfer (FRET-) experiments. Individual nanocrystal-dye complexes are investigated by single particle fluorescence microscopy and spectroscopy to show large inhomogeneities among the prepared structures.