In situ electron microscopy experiments can provide the most revealing insights into material behavior. However, in order to take full advantage of the observations, quantitative measurements are required so that the underlying mechanisms are completely interpreted. This approach also ensures that specimen and environmental artifacts do not play a role and that real “bulk” processes are being studied. These points are illustrated in this paper by reference to work on reactions in semiconductor systems, especially at high resolution.The technique and practice of in situ microscopy are quite exacting. Thus it is often necessary to record changes in the same specimen area for extensive periods of time (e.g., hours), under identical imaging conditions. One can never be sure when a significant event will take place, or sometimes whether it has actually occurred -- accordingly a high degree of acuity on behalf of the observer is essential. A number of procedures is recommended to check that the results are representative and reproducible, including comparing the structural evolution with that from ex situ samples both qualitatively and quantitatively (e.g., [1]). Some contemporary applications are given in a recent publication.
Dynamic structural evolution of supported palladium–ceria core–shell catalysts revealed by in situ electron microscopy