Direction-Specific Interactions Control Crystal Growth by Oriented Attachment

Growing in Liquid The ability to control the growth of materials at the nanometer scale is key to nanotechnology. Materials grown in liquids, however, are difficult to track on a particle-by-particle basis during growth. Two studies used an in situ liquid cell to follow the formation of larger nanoparticles or nanorods grown in solvents using high-resolution transmission electron microscopes. Liao et al. (p. 1011 ) watched platinum iron nanorods form from kinked chains of connected nanoparticles that gradually reoriented and straightened to form rigid rods. Li et al. (p. 1014 ) observed the coalescence of iron oxyhydroxide nanoparticles through an oriented attachment mechanism, whereby two similar particles rotated until their corresponding crystal lattices aligned.