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https://hku.zoom.us/j/96856803269?pwd=pe5KN7jrazHsxSgY19zeaybJ4CsbKb.1

Meeting ID: 968 5680 3269

Password: 321512

Abstract:

Understanding the dynamics of excited states is essential for comprehending the operational principles of optoelectronic materials and devices. In traditional spectroscopic approaches, transient absorption spectroscopy (pump-probe) and time-resolved photoluminescence measurements are widely employed to probe the behaviour of excited states. However, both methods necessitate the application of algorithms and/or models to decouple the contributions of various excited states, enabling the determination of time constants for distinct photophysical processes. The complexity and variety in modelling can result in a multitude of potential interpretations when analysing spectroscopic signals.

To tackle these challenges, we've developed cutting-edge ultrafast infrared optical activation spectroscopy. This innovative approach involves the introduction of a time-delayed infrared pulse, serving as a "push" pulse, which allows us to experimentally and directly observe the dynamics of hot carriers (via the pump-push-probe technique) and the behaviour of trapped carriers (via the pump-push-photocurrent technique). In this presentation, we not only introduce these state-of-the- art spectroscopic techniques but also showcase their applications on perovskite materials/devices, including hot carrier relaxation and the dynamics of trapped carriers.

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