Microwave-Assisted Synthesis of Colloidal Inorganic Nanocrystals

Colloidal inorganic nanocrystals stand out as an important class of advanced nanomaterials owing to the flexibility with which their physical-chemical properties can be controlled through size, shape, and compositional engineering in the synthesis stage and the versatility with which they can be implemented into technological applications in fields as diverse as optoelectronics, energy conversion/production, catalysis, and biomedicine. The use of microwave irradiation as a non-classical energy source has become increasingly popular in the preparation of nanocrystals (which generally involves complex and time-consuming processing of molecular precursors in the presence of solvents, ligands and/or surfactants at elevated temperatures). Similar to its now widespread use in organic chemistry, the efficiency of "microwave flash heating" in dramatically reducing overall processing times is one of the main advantages associated with this technique. This Review illustrates microwave-assisted methods that have been developed to synthesize colloidal inorganic nanocrystals and critically evaluates the specific roles that microwave irradiation may play in the formation of these nanomaterials. If you can't stand the heat, get out of the kitchen: Direct volumetric and efficient heating by microwave irradiation enables the generation of colloidal nanocrystals in a fraction of the time required using conventional heating techniques (see picture). Among the advantages of this non-classical heating method is a great control of reaction temperature, allowing better versatility, reproducibility, and reduced processing times in the fabrication of high-quality nanocrystals. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.