With its combination of spatial and temporal resolution in water, liquid cell transmission electron microscopy is a useful tool for measuring reaction kinetics and understanding reaction pathways. It has already provided unique insights into processes such as solution-phase nanoparticle formation and electrochemical deposition. However, a challenge in interpreting liquid cell data is determining the local reaction parameters, for example pH or ion concentration, in the region under observation. In this presentation we discuss the reasons for this uncertainty and consider possible solutions. One key issue is the effect of the imaging beam itself on the solution chemistry. The high radiation dose required for imaging drives radiolytic reactions that chemically change the local liquid environment. We find that simulations can be a helpful tool in understanding the effects of irradiation. We consider, in particular, how the geometry of the electron beam and the interfaces between the liquid and its enclosure might be expected to affect the local chemistry. We discuss how the simulations can be tested and assess future prospects for improving the accuracy with which reaction parameters are known. Better quantification is essential in interpreting liquid cell data on nanoparticle synthesis and related areas, and can even lead to strategies that use beam effects to fabricate more complex nanostructures.

Improving quantification in liquid cell electron microscopy of materials reactions

256th National Meeting (2018)

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