Molecular precursors for (nano) materials - a one step strategy

摘要

The use of molecular Single Source Precursors (SSP) containing all elements necessary for the formation of the final solid material in CVD (Chemical Vapor Deposition) or sol-gel routes is classified with respect to the control of the reaction. Three different cases have been distinguished: In SSP-I the stoichiometric ratio of the elements in the precursor corresponds to the ratio required in the solid whereas the number and kind of side products of the reaction (ligands) are not controlled. In SSP-II, not only does the ratio of the elemental components of the precursor have the correct stoichiometry but also the ligands are chosen in such a way what a cascade of reactions is induced at moderate temperatures leading to few products and therefore low contamination of the solid material. In SSP-III, the precursor decomposes to form at least two solid phases with perfect stochiometric and structural control. All three processes allow the obtention of nanocrystalline materials.