Probing integration strength of colloidal spheres self-assembled from TiO2 nanocrystals by in-situ TEM indentation

Small building blocks such as molecules and nanoparticles, with controlled size, shape, and properties, have been recently utilized as artificial building blocks to assemble two- or three-dimensional structures via “bottom up” processes. Unlike the well known ionic, metallic, or covalent bonds combining “real” atoms, the nature of the bonding between these small aggregates, and the mechanical stability of the selfassemblies, are far from clear. Recent development of in-situ TEM nanoindentation technique enables simultaneous monitoring of mechanical and structural responses of a nanosized cluster under externally applied load at real time in high resolution TEM.