Monodisperse isotropic nanoparticles

At present, most of the related efforts on ligand chemistry of nanociystals are focused on the development of new types of ligands [47, 48] and different passivation strategies [49] to satisfy stability requirements for certain types of applications. Typical ligands for colloidal nanociystals, such as thiolates (deprotonated products of thiols), amines, phosphonates (deprotonated products of phosphonic acids), and carbojg lates (deprotonated products of carboxylic acids), etc., are all Lewis bases. Ligand systems can consit of hexadecylamine, dodecylamine, and octylamine on one side (HD Am, DDAm, and Oct Am) and octanoic acid, oleic acid, and lauric acid on the other (OctA, OA, and LcA) [50]. The presence of a carboxylic acid is essential to obtain monodisperse isotropic nanoparticles but that the nature of the amine and acid ligands has only a very limited influence on the size of the metal particles. This is not the case in pH variation. In... 

In summary, control of the surface chemistry and the presence of clean surfaces allow the coalescence of initially isotropic nanoparticles into regular, often monodisperse, nano-objects of anisotropic shape (cubes, rods, wires). It is possible that the inclusion of the initially present nanoparticles into superlattices play an important role in these coalescence processes. 

Although several reports exist describing a variety of synthetic approaches for isotropic palladium nanoparticles, a major challenge exists in the ability to produce well-defined and monodisperse Pd nanoparticles. For wet-chemical methods used in the preparation of palladium nanoparticles, both organic and inorganic Pd compounds have been used as precursors. The oxidation state of the Pd compounds largely dictates the reaction conditions under which the synthetic procedure will ensue. For example, the decomposition of zerovalent organometallic Pd complexes is usually performed in an air-free environment with well-controlled... 

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