In-situ

What is in-situ microscopy?

In-situ transmission electron microscopy combines the image formation capabilities of the transmission electron microscope (TEM) with the application of one or more external stimuli to observe real-time sample dynamics. Currently, a wide variety of systems and holders are available to apply different stimuli to evaluate dynamics during electrical biasing, mechanical strain/deformation, heating, cooling, the introduction of gaseous or liquid environments, or simply intense electron beam irradiation.

Historically, movies of various reactions and system kinetics could be recorded onto videotape. Screen capture programs improved upon this allowing low-resolution, qualitative video capture to visualize what is happening at speeds up to video frame rates, e.g., 30 frames per second (fps).

Now with the advent of faster data transfer and processing capabilities, it is possible with Gatan IS cameras to record and manage large datasets directly from the sensor output. The original, quantitative data from each frame captured during an experimental session can be stored directly to disk and treated as individual images or played back as a video. Additionally, various algorithms or scripts (e.g., summing, drift correction, binning) can be applied post-capture to extract the most useful parts of the acquired data, as seen in the videos below. The built-in data management tools available with Gatan IS cameras allow data to be isolated and extracted easily so that post-processing data analysis can be performed to quantify the observed effects of the stimuli applied to the system. This data capture and post-processing workflow greatly increases the number of experiments that can be performed during a microscopy session. This increase enables previously unachievable resolution in time and space, with sub-ms time resolution, allows reactions to be studied that had been too fast to capture, and makes it possible to resolve dynamics that previously were unknown.

This data shows both the stability of the combination of a Gatan OneView^® IS camera with a DENSsolutions Wildfire heating holder at 1300 ⁰C. A change in particle shape is captured with good spatial and temporal resolution immediately following a temperature change. It was not known apriori which particle(s) might transform, but all these particles could be observed with the same spatial resolution simultaneously due to the large field of view of the OneView IS camera.

The main video is played back at 10x speed, but the shape transformation of the particle is played back at 2x speed. The inset is also zoomed in to show that lattice fringes were resolved. 

This video has not been drift-corrected or cropped. Frames were averaged together to improve the signal-to-noise of the video. Sample: Ru on SiO₂. 

The thin-film sintering of Au sputtered on SiNx was captured with the Rio^® 16 IS camera. The sample was heated to 650 °C using a DENSsolutions Wildfire heating holder. This video has been drift-corrected and cropped using the IS player within DigitalMicrograph^® software. 

This data shows the movement of individual atomic columns on the surface of a small CeO₂ nanoparticle at 400 fps. The movement was induced by the incident electron beam at room temperature. The temporal resolution of the K2^® IS camera enables these movements to be seen.

The video plays back at two different speeds (1/2 and 1/10 real speed) so that one section of the video where significant movement takes place can be watched in detail. Even during this slow section, a few frames are skipped, because the video frame rate is 30 fps, while the data is still 40 fps at 1/10th speed.

This video has been drift-corrected, background-subtracted, filtered, and cropped.