CdS nanocrystals from a quaternary water-in-oil microemulsion: Preparationand characterization of self-assembled layers

High-crystalline CdS nanocrystals, prepared by means of an improved synthet ic route that exploits a quaternary water-in-oil microemulsion are immobili zed on gold and quartz substrates by self-assembly. The obtained nanocrysta ls and layers are characterised by scanning tunneling microscopy, X-ray pho toelectron spectroscopy, X-ray diffraction, and UV-vis spectroscopy. The re sults indicate that the CdS nanocrystals show a good adherence to the subst rate, are quite stable in air for months, and still retain their size and q uantum properties after immobilization. The data are discussed in terms of the increased stability of the nanocrystals in solution due to the presence of the co-surfactant that acts as capping agent. (C) 2001 Academic Press.