Title: Photoinduced Charge Transport Dynamics Probed by Ultrafast Laser
Speaker: Ms. Chhavi Sarma from NPL Delhi
Abstract: Understanding the fast electronic transitions occurring inside a material gives us valuable insights into the photo-physical properties of the material. Common experimental techniques fail to capture such dynamic and fast natured events. However, by using an ultrafast laser based pump probe technique like ultrafast transient absorption to track the dynamics of photo-excited charge carriers at ultrafast timescales of femtosecond to nanoseconds. Such high time resolution can be exploited to investigate dynamic evolution of absorption of excited species. We can also track the real-time dynamics of processes like - intersystem crossing, non-radiative relaxation, internal conversion and vibration relaxation. Knowing this can potentially help us understand about the charge carrier loss pathways involving extremely fast energy or charge transfer processes. CSIR-NPL has established a core research expertise in the area of energy harvesting through their research in the organic, inorganic and oxide materials for the development of solar energy, photovoltaics and thermoelectric. I have been using the ultrafast technique as a tool to characterize such material systems for efficient energy harvesting resulting in various materials advancements. My talk will provide a brief introduction of this technique while giving you insights into its working and advantages over other techniques. I will provide some examples illustrating the potentials of this technique that helped to improve the energy harvesting efficiency in the form of - enhanced power conversion efficiency using luminescent QDs, and efficient charge transfer for sensing application. Further, the talk will touch upon the current studies on semi-metal nanostructures showcasing their photo-physical properties.
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