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Seminar on How to Map Ultrafast Carrier Dynamics on Photoactive Material Surfaces and Device Interfaces in Real Space and Time

By Dr. Omar F. Mohammed

Assistant Professor of Chemical Science in Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST)

CENT invited Dr. Omar Muhammed, an Assistant Professor of Chemical Science in Solar and Photovoltaics at the Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST) to deliver a seminar on How to Map Ultrafast Carrier Dynamics on Photoactive Material Surfaces and Device Interfaces in Real Space and Time on Wednesday, 1st of March, 2017at the Research Institute Building 15. The event started with the introduction of the speaker by Dr. Safyan Khan of CENT, the speaker started his presentation with an introduction to KAUST and her research capabilities before introducing the scopes of discussion in the seminar, the scopes are pump-probe in laser spectroscopy and electron microscopy, charge transfer dynamics at interfaces and Four-Dimensional (4D) electron imaging: from concept to unique applications. He described the pump probe concept in spectroscopy as the best technique in probing the surface of materials with minimal interference from the bulk and discussed the unique applications such as in probing carrier dynamics at interface P/N junctions/water splitting, electron injection in QD-Photocatalysis solar cells, carrier dynamics in real space and heat transfer on surfaces highlighting specific applications on how charge transfer can be probe in organic compounds, quantom dots (QD) and perovskites using specific examples from his research works published in different renowned journals. He later discussed how real space mapping of carrier dynamics on material surface and interface can be selectively achieved using 4D imaging where he discussed the experimental set up of a second generation four-dimensional scanning ultrafast electron microscopy (4D S-UEM) at KAUST and demonstrated its ability to take time-resolved secondary electron images of material surfaces with 650fs temporal and approximately 5nm spatial resolution. He highlighted various research work where the 4D S-UEM have been used to successfully detect carrier dynamics in Si P/N junctions, on semiconductor CdSe surfaces, on semiconductor nanowires before and after treatment, on semiconductor QDs before and after treatment, thin films, carrier diffusion on material surfaces, and heat transfer on material surfaces. He concluded the presentation by highlighting the importance and other applications of the 4D S-UEM.

Some event pictures are shown below:

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