Toward Ending the Guessing Game: Study of the Formation of Nanostructures Using in Situ Liquid Transmission Electron Microscopy

The field of synthetic nanochemistry has grown tremendously in the past three decades since the discovery of nonaqueous synthesis of monodispersed particles. Almost all classes of materials, from II-VI semiconductor to metal, alloy, and metal oxide can now be prepared in various sizes and shapes. One major challenge has been the development of a technique for direct real-time recording of data during the formation of nanostructures in liquid reaction media where nucleation and growth occur. A viable solution finally arrived with the recent development of static and flow liquid cells for transmission electron microscopy (TEM). This Perspective will showcase a few selected examples in this rapidly growing area, with a focus on using the new capabilities of liquid TEM (LTEM) for quantitative study of nucleation and growth, as well as shape formation of nanocrystals in solution. A discussion on future direction is also presented.