In Situ Ultrafast Carrier Dynamics in Quantum Materials Devices

The understanding of ultrafast carrier dynamics is the foundation of quantum materials applications in renewable energy, nanotechnology, and quantum information and technology. To reveal the ultrafast dynamics, the majority research groups rely on classic ultrafast optical spectroscopies such as pump-probe transient absorption spectroscopy and time-resolved photoluminescence. Although these non-contact photon-in and photon-out approaches have made revolutionary discoveries, which have been demonstrated by our pioneers’ work in Femtochemistry (Zewail, 1999), super resolution microscopy (Hell, 2014), and chirped pulsed amplification (Strickland, 2018), they lack an<i> in-situ</i> feature for characterizing building block devices such as solar cells, LEDs, photoconductors, transistors, etc..<br/>In this talk, I will highlight the ultrafast photocurrent spectroscopy that we have developed to bridge the gap between classic optical spectroscopies and carrier dynamics <i>in-situ</i> devices. In particular, I will focus on quantum materials including perovskite nanocrystals and 2D layer transition metal dichalcogenide (TMDC). Because of their unique quantum confinement effect, leading to the novel phenomena such as hot carrier and exciton condensation, the understanding of ultrafast dynamics may lead to next generation hot carrier solar cells and room temperature superconductors.