  High resolution nanoscale imaging in liquid environments is crucial for
studying molecular interactions in biological and chemical systems. In
particular, electron microscopy is the gold-standard tool for nanoscale
imaging, but its high-vacuum requirements make application to in-liquid samples
extremely challenging. Here we present a new graphene based wet cell device
where high resolution SEM (scanning electron microscope) and Energy Dispersive
X-rays (EDX) analysis can be performed directly inside a liquid environment.
Graphene is an ideal membrane material as its high transparancy, conductivity
and mechanical strength can support the high vacuum and grounding requirements
of a SEM while enabling maximal resolution and signal. In particular, we obtain
high resolution (< 5 nm) SEM video images of nanoparticles undergoing brownian
motion inside the graphene wet cell and EDX analysis of nanoparticle
composition in the liquid enviornment. Our obtained resolution surpasses
current conventional silicon nitride devices imaged in both SEM and TEM under
much higher electron doses.
