Multistage Transformation and Lattice Fluctuation at AgCl−Ag Interface

Jingshan S. Du, Jungwon Park, QHwan Kim, Wonho Jhe, Vinayak P. Dravid, Deren Yang, David A. Weitz

Solid-state transformation between diff erent materials is often accompanied

by mechanical expansion and compression due to their volume change and

structural evolution at interfaces. However, these two types of dynamics are usually

diffi cult to monitor in the same time. In this work, we use in situ transmission electron

microscopy to directly study the reduction transformation at the AgCl− Ag interface.

Three stages of lattice fl uctuations were identifi ed and correlated to the structural

evolution. During the steady state, a quasi-layered growth mode of Ag in both vertical and

lateral directions were observed due to the confi nement of AgCl lattices. The development

of planar defects and depletion of AgCl are respectively associated with lattice

compression and relaxation. Topography and structure of decomposing AgCl was further

monitored by in situ scanning transmission electron microscopy. Silver species are

suggested to originate from both the surface and the interior of AgCl, and be transported

to the interface. Such mass transport may have enabled the steady state and lattice

compression in this volume-shrinking transformation.