Open gas-cell transmission electron microscopy at 0.5 Å information limit

Transmission electron microscopy (TEM) has reached ∼ 0.5 Å information limit in high vacuum conditions, enabling single-atom sensitive imaging of nanomaterials. Extending this capability to gaseous environments would allow for similar visualizations of nanomaterial dynamics under chemically reactive conditions. Here, we examine a new TEM system that obtains 0.5 Å information limit at pressures up to 1 mbar, demonstrated using nanocrystalline Au immersed in N₂. The system features an open gas-cell with a four-stage differential pumping system, a 5^th order aberration corrector for broad-beam TEM, a monochromatized electron beam, an ultra-stable microscope platform, Nelsonian low electron dose-rate illumination, and direct electron detection. Young's fringe experiments and exit wave phase imaging confirm the atomic resolution and indicate a possible location-dependent vibrational blur at a surface termination. Thus, this platform advances in situ and operando TEM studies of gas-surface interactions in diverse fields, including catalysis, corrosion, and crystal growth.