Tracking Metal Electrodeposition Dynamics from Nucleation and Growth of a Single Atom to Crystalline Nanoparticle
H. E. M. Hussein, R. J. Maurer, H. Amari, J. J. P. Peters, L. Meng, R. Beanland, M. E. Newton, J. V. Macpherson, ACS Nano, in press (2018)
"Identical Location Scanning Transmission Electron Microscopy and Density Functional Theory calculations give the first account of electrochemically-driven gold deposition with single-atom resolution."
In electrodeposition, the key challenge is to obtain better control over nanostructure morphology. Currently, a lack of understanding exists concerning the initial stages of nucleation and growth, which ultimately impact the physicochemical properties of the resulting entities. Using identical location scanning transmission electron microscopy (STEM), with boron-doped diamond (BDD) serving as both an electron transparent TEM substrate and electrode, we follow this process, from the formation of an individual atom through to a crystalline nanoparticle, under potential pulsed conditions. In doing so, we reveal the importance of electrochemically driven atom transport, atom cluster formation, cluster progression to a nanoparticle and the mechanism by which neighboring particles interact during growth. Such information will help formulate new models and promote wider uptake of electrodeposited structures in a wide range of societally important applications. This type of measurement is possible in the TEM because the BDD possesses inherent stability, has an extremely high thermal conductivity, is electron beam transparent, free from contamination and robust enough for multiple depositions and imaging cycles. Moreover, the platform can be operated under conditions such that we have confidence that the dynamic atom events we image are truly due to electrochemically driven deposition and no other factors, such as electron beam induced movement.