Nanocrystals By The Kilogram

Kilogram-scale batches of uniform-sized nanocrystals can be prepared via a simple synthesis procedure, according to researchers in South Korea. The availability of a low-cost method for making bulk quantities of monodisperse (single-sized) nanocrystals may speed up development of nanotechnology applications. Several methods for preparing monodisperse nanocrystals have already been reported, but typically those methods yield gram quantities of product and require size-sorting steps. Taeghwan Hyeon, a professor of chemical engineering at Seoul National University, reported that his research group, in collaboration with Wan-Jae Myeong and coworkers at Hanwha Chemical, also in Seoul, have synthesized kilogram-scale batches of uniformly sized 11-nm-diameter magnetite (Fe₃O₄) crystals via a procedure they developed. The method, which takes less than seven hours to complete and does not require size-sorting steps, calls for reacting a surfactant with hydrated iron chloride, an inexpensive reagent, and then heating the complex slowly in a high-boiling-point solvent. Scaling the synthesis even further may be particularly useful for applications in data storage, medical imaging, and magnetically directed drug delivery.