Programming structure into 3D nanomaterials

JUNE 2009 | VOLUME 12 | NUMBER 6 28 The selfand directed assembly of materials has been of considerable interest for a number of years, however only recently has it become possible to program structure and properties on the nanoscale with the precision required for a number of important applications. It is now possible to define, with nanometer accuracy, the complete 3D structure of functional solids using various templating approaches. Rapid progress has been made in designing molecular and colloidal templates for inorganic solids at length scales ranging from a few to 100s of nanometers. Despite the many recent advances in forming molecular and colloidal building blocks with increasing complexity, often the resultant self-assembled structures and templates formed from these materials can not generate the desired complex nanostructure. In such cases, other structure programming approaches, such as multibeam optical interference are being utilized to create 3D nanostructured solids with almost limitless structural complexity. Optical interference has the unique ability to create virtually any periodic structure through control of the phase, intensity, polarization and direction of the interfering laser beams, although to date, the minimum characteristic dimension of structures formed via optical interference is greater than those formed via molecular-based templating strategies.