Colloquium: Investigating Nanostructure Synthesis Using In Situ TEM
Understanding the fundamental relationship between atomic structure and material properties is the holy grail of the science of materials. Towards this goal we are working to develop a real-time and atomistic understanding of the mechanistic steps taken during the growth and transformation of crystalline materials. To do this we employ a combination of complementary synthetic and characterization approaches, in particular using in situ ultra-high resolution transmission electron microscopy (TEM) to observe key structural transformations in real-time. Our in situ experiments include directly performing nanomaterial synthesis in the TEM, as well as determining the kinetics of structural phase transformations of as-synthesized inorganic nanocrystals. Further, based on an unexpected observation made during one of these in situ measurements, we have developed a new approach to directly synthesize arrays of crystallographically well-defined nanoscale interfaces. Several examples will be presented to illustrate our approach, including: the real-time observation of the solid-state reaction of an individual nanowire; a post-synthetic structural phase transformation within an individual nanorod; and finally, the creation of new nanostructured architectures using liquid metal nanodroplets.